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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / edd7d11690027b9ff9387d85b7c235cd7fd2cf20 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]25 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26 <li><a href="#globalvars">Global Variables</a></li>
27 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]28 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]30 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]31 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]32 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
33 <li><a href="#datalayout">Data Layout</a></li>
34 </ol>
35 </li>
36 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]38 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39 <li><a href="#t_primitive">Primitive Types</a>
40 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]41 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]44 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]45 </ol>
46 </li>
47 <li><a href="#t_derived">Derived Types</a>
48 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]49 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50 <li><a href="#t_array">Array Type</a></li>
51 <li><a href="#t_function">Function Type</a></li>
52 <li><a href="#t_pointer">Pointer Type</a></li>
53 <li><a href="#t_struct">Structure Type</a></li>
54 <li><a href="#t_pstruct">Packed Structure Type</a></li>
55 <li><a href="#t_vector">Vector Type</a></li>
56 <li><a href="#t_opaque">Opaque Type</a></li>
57 </ol>
58 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]59 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]60 </ol>
61 </li>
62 <li><a href="#constants">Constants</a>
63 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]64 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]65 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]66 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
67 <li><a href="#undefvalues">Undefined Values</a></li>
68 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]69 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]70 </ol>
71 </li>
72 <li><a href="#othervalues">Other Values</a>
73 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]74 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]75 </ol>
76 </li>
77 <li><a href="#instref">Instruction Reference</a>
78 <ol>
79 <li><a href="#terminators">Terminator Instructions</a>
80 <ol>
81 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
82 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
83 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
84 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
85 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
86 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
87 </ol>
88 </li>
89 <li><a href="#binaryops">Binary Operations</a>
90 <ol>
91 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]92 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]93 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]94 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]95 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]96 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]97 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
98 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
99 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
100 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
101 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
102 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
103 </ol>
104 </li>
105 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
106 <ol>
107 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
108 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
109 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
110 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
111 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
112 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
113 </ol>
114 </li>
115 <li><a href="#vectorops">Vector Operations</a>
116 <ol>
117 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
118 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
119 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
120 </ol>
121 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]122 <li><a href="#aggregateops">Aggregate Operations</a>
123 <ol>
124 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
125 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
126 </ol>
127 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
129 <ol>
130 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
131 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
132 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
133 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
134 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
135 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
136 </ol>
137 </li>
138 <li><a href="#convertops">Conversion Operations</a>
139 <ol>
140 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
141 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
142 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
143 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
144 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
145 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
146 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
147 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
148 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
149 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
150 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
151 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
152 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]153 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]154 <li><a href="#otherops">Other Operations</a>
155 <ol>
156 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
157 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
158 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
159 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
160 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
161 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
162 </ol>
163 </li>
164 </ol>
165 </li>
166 <li><a href="#intrinsics">Intrinsic Functions</a>
167 <ol>
168 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
169 <ol>
170 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
171 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
172 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
173 </ol>
174 </li>
175 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
176 <ol>
177 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
178 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
179 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
180 </ol>
181 </li>
182 <li><a href="#int_codegen">Code Generator Intrinsics</a>
183 <ol>
184 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
185 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
186 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
187 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
188 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
189 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
190 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
191 </ol>
192 </li>
193 <li><a href="#int_libc">Standard C Library Intrinsics</a>
194 <ol>
195 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]200 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
201 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
202 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]203 </ol>
204 </li>
205 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
206 <ol>
207 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
208 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
210 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]211 </ol>
212 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]213 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
214 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]215 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
219 <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]220 <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]221 </ol>
222 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]223 <li><a href="#int_debugger">Debugger intrinsics</a></li>
224 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]225 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]226 <ol>
227 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]228 </ol>
229 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]230 <li><a href="#int_atomics">Atomic intrinsics</a>
231 <ol>
232 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
233 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
234 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
235 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
236 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
237 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
238 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
239 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
240 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
241 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
242 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
243 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
244 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
245 </ol>
246 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]247 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]248 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]249 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]250 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]251 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]252 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]253 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]254 '<tt>llvm.trap</tt>' Intrinsic</a></li>
255 <li><a href="#int_stackprotector">
256 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]257 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]258 </li>
259 </ol>
260 </li>
261</ol>
262
263<div class="doc_author">
264 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
265 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
266</div>
267
268<!-- *********************************************************************** -->
269<div class="doc_section"> <a name="abstract">Abstract </a></div>
270<!-- *********************************************************************** -->
271
272<div class="doc_text">
273<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]274LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]275type safety, low-level operations, flexibility, and the capability of
276representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]277representation used throughout all phases of the LLVM compilation
278strategy.</p>
279</div>
280
281<!-- *********************************************************************** -->
282<div class="doc_section"> <a name="introduction">Introduction</a> </div>
283<!-- *********************************************************************** -->
284
285<div class="doc_text">
286
287<p>The LLVM code representation is designed to be used in three
288different forms: as an in-memory compiler IR, as an on-disk bitcode
289representation (suitable for fast loading by a Just-In-Time compiler),
290and as a human readable assembly language representation. This allows
291LLVM to provide a powerful intermediate representation for efficient
292compiler transformations and analysis, while providing a natural means
293to debug and visualize the transformations. The three different forms
294of LLVM are all equivalent. This document describes the human readable
295representation and notation.</p>
296
297<p>The LLVM representation aims to be light-weight and low-level
298while being expressive, typed, and extensible at the same time. It
299aims to be a "universal IR" of sorts, by being at a low enough level
300that high-level ideas may be cleanly mapped to it (similar to how
301microprocessors are "universal IR's", allowing many source languages to
302be mapped to them). By providing type information, LLVM can be used as
303the target of optimizations: for example, through pointer analysis, it
304can be proven that a C automatic variable is never accessed outside of
305the current function... allowing it to be promoted to a simple SSA
306value instead of a memory location.</p>
307
308</div>
309
310<!-- _______________________________________________________________________ -->
311<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
312
313<div class="doc_text">
314
315<p>It is important to note that this document describes 'well formed'
316LLVM assembly language. There is a difference between what the parser
317accepts and what is considered 'well formed'. For example, the
318following instruction is syntactically okay, but not well formed:</p>
319
320<div class="doc_code">
321<pre>
322%x = <a href="#i_add">add</a> i32 1, %x
323</pre>
324</div>
325
326<p>...because the definition of <tt>%x</tt> does not dominate all of
327its uses. The LLVM infrastructure provides a verification pass that may
328be used to verify that an LLVM module is well formed. This pass is
329automatically run by the parser after parsing input assembly and by
330the optimizer before it outputs bitcode. The violations pointed out
331by the verifier pass indicate bugs in transformation passes or input to
332the parser.</p>
333</div>
334
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]335<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]336
337<!-- *********************************************************************** -->
338<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
339<!-- *********************************************************************** -->
340
341<div class="doc_text">
342
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]343 <p>LLVM identifiers come in two basic types: global and local. Global
344 identifiers (functions, global variables) begin with the @ character. Local
345 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]346 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]347
348<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]349 <li>Named values are represented as a string of characters with their prefix.
350 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
351 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]352 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]353 with quotes. Special characters may be escaped using "\xx" where xx is the
354 ASCII code for the character in hexadecimal. In this way, any character can
355 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]356
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]357 <li>Unnamed values are represented as an unsigned numeric value with their
358 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]359
360 <li>Constants, which are described in a <a href="#constants">section about
361 constants</a>, below.</li>
362</ol>
363
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]364<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]365don't need to worry about name clashes with reserved words, and the set of
366reserved words may be expanded in the future without penalty. Additionally,
367unnamed identifiers allow a compiler to quickly come up with a temporary
368variable without having to avoid symbol table conflicts.</p>
369
370<p>Reserved words in LLVM are very similar to reserved words in other
371languages. There are keywords for different opcodes
372('<tt><a href="#i_add">add</a></tt>',
373 '<tt><a href="#i_bitcast">bitcast</a></tt>',
374 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
375href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
376and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]377none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]378
379<p>Here is an example of LLVM code to multiply the integer variable
380'<tt>%X</tt>' by 8:</p>
381
382<p>The easy way:</p>
383
384<div class="doc_code">
385<pre>
386%result = <a href="#i_mul">mul</a> i32 %X, 8
387</pre>
388</div>
389
390<p>After strength reduction:</p>
391
392<div class="doc_code">
393<pre>
394%result = <a href="#i_shl">shl</a> i32 %X, i8 3
395</pre>
396</div>
397
398<p>And the hard way:</p>
399
400<div class="doc_code">
401<pre>
402<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
403<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
404%result = <a href="#i_add">add</a> i32 %1, %1
405</pre>
406</div>
407
408<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
409important lexical features of LLVM:</p>
410
411<ol>
412
413 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
414 line.</li>
415
416 <li>Unnamed temporaries are created when the result of a computation is not
417 assigned to a named value.</li>
418
419 <li>Unnamed temporaries are numbered sequentially</li>
420
421</ol>
422
423<p>...and it also shows a convention that we follow in this document. When
424demonstrating instructions, we will follow an instruction with a comment that
425defines the type and name of value produced. Comments are shown in italic
426text.</p>
427
428</div>
429
430<!-- *********************************************************************** -->
431<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
432<!-- *********************************************************************** -->
433
434<!-- ======================================================================= -->
435<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
436</div>
437
438<div class="doc_text">
439
440<p>LLVM programs are composed of "Module"s, each of which is a
441translation unit of the input programs. Each module consists of
442functions, global variables, and symbol table entries. Modules may be
443combined together with the LLVM linker, which merges function (and
444global variable) definitions, resolves forward declarations, and merges
445symbol table entries. Here is an example of the "hello world" module:</p>
446
447<div class="doc_code">
448<pre><i>; Declare the string constant as a global constant...</i>
449<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
450 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
451
452<i>; External declaration of the puts function</i>
453<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
454
455<i>; Definition of main function</i>
456define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]457 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]458 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]459 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]460
461 <i>; Call puts function to write out the string to stdout...</i>
462 <a
463 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
464 <a
465 href="#i_ret">ret</a> i32 0<br>}<br>
466</pre>
467</div>
468
469<p>This example is made up of a <a href="#globalvars">global variable</a>
470named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
471function, and a <a href="#functionstructure">function definition</a>
472for "<tt>main</tt>".</p>
473
474<p>In general, a module is made up of a list of global values,
475where both functions and global variables are global values. Global values are
476represented by a pointer to a memory location (in this case, a pointer to an
477array of char, and a pointer to a function), and have one of the following <a
478href="#linkage">linkage types</a>.</p>
479
480</div>
481
482<!-- ======================================================================= -->
483<div class="doc_subsection">
484 <a name="linkage">Linkage Types</a>
485</div>
486
487<div class="doc_text">
488
489<p>
490All Global Variables and Functions have one of the following types of linkage:
491</p>
492
493<dl>
494
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]495 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
496
497 <dd>Global values with private linkage are only directly accessible by
498 objects in the current module. In particular, linking code into a module with
499 an private global value may cause the private to be renamed as necessary to
500 avoid collisions. Because the symbol is private to the module, all
501 references can be updated. This doesn't show up in any symbol table in the
502 object file.
503 </dd>
504
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]505 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]506
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]507 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]508 the case of ELF) in the object file. This corresponds to the notion of the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]509 '<tt>static</tt>' keyword in C.
510 </dd>
511
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]512 <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
513 </dt>
514
515 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
516 into the object file corresponding to the LLVM module. They exist to
517 allow inlining and other optimizations to take place given knowledge of the
518 definition of the global, which is known to be somewhere outside the module.
519 Globals with <tt>available_externally</tt> linkage are allowed to be discarded
520 at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
521 type is only allowed on definitions, not declarations.</dd>
522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]523 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
524
525 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
526 the same name when linkage occurs. This is typically used to implement
527 inline functions, templates, or other code which must be generated in each
528 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
529 allowed to be discarded.
530 </dd>
531
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]532 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
533
534 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
535 linkage, except that unreferenced <tt>common</tt> globals may not be
536 discarded. This is used for globals that may be emitted in multiple
537 translation units, but that are not guaranteed to be emitted into every
538 translation unit that uses them. One example of this is tentative
539 definitions in C, such as "<tt>int X;</tt>" at global scope.
540 </dd>
541
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]542 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
543
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]544 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
545 that some targets may choose to emit different assembly sequences for them
546 for target-dependent reasons. This is used for globals that are declared
547 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]548 </dd>
549
550 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
551
552 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
553 pointer to array type. When two global variables with appending linkage are
554 linked together, the two global arrays are appended together. This is the
555 LLVM, typesafe, equivalent of having the system linker append together
556 "sections" with identical names when .o files are linked.
557 </dd>
558
559 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]560
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]561 <dd>The semantics of this linkage follow the ELF object file model: the
562 symbol is weak until linked, if not linked, the symbol becomes null instead
563 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]564 </dd>
565
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]566 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]568 <dd>Some languages allow differing globals to be merged, such as two
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]569 functions with different semantics. Other languages, such as <tt>C++</tt>,
570 ensure that only equivalent globals are ever merged (the "one definition
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]571 rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Duncan Sandsb95df792009-03-11 20:14:15 +0000[diff] [blame]572 and <tt>weak_odr</tt> linkage types to indicate that the global will only
573 be merged with equivalent globals. These linkage types are otherwise the
574 same as their non-<tt>odr</tt> versions.
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]575 </dd>
576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]577 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
578
579 <dd>If none of the above identifiers are used, the global is externally
580 visible, meaning that it participates in linkage and can be used to resolve
581 external symbol references.
582 </dd>
583</dl>
584
585 <p>
586 The next two types of linkage are targeted for Microsoft Windows platform
587 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]588 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]589 </p>
590
591 <dl>
592 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
593
594 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
595 or variable via a global pointer to a pointer that is set up by the DLL
596 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]597 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]598 </dd>
599
600 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
601
602 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
603 pointer to a pointer in a DLL, so that it can be referenced with the
604 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]605 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]606 name.
607 </dd>
608
609</dl>
610
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]611<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]612variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
613variable and was linked with this one, one of the two would be renamed,
614preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
615external (i.e., lacking any linkage declarations), they are accessible
616outside of the current module.</p>
617<p>It is illegal for a function <i>declaration</i>
Duncan Sands565f65d2009-03-11 08:08:06 +0000[diff] [blame]618to have any linkage type other than "externally visible", <tt>dllimport</tt>
619or <tt>extern_weak</tt>.</p>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]620<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
621or <tt>weak_odr</tt> linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]622</div>
623
624<!-- ======================================================================= -->
625<div class="doc_subsection">
626 <a name="callingconv">Calling Conventions</a>
627</div>
628
629<div class="doc_text">
630
631<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
632and <a href="#i_invoke">invokes</a> can all have an optional calling convention
633specified for the call. The calling convention of any pair of dynamic
634caller/callee must match, or the behavior of the program is undefined. The
635following calling conventions are supported by LLVM, and more may be added in
636the future:</p>
637
638<dl>
639 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
640
641 <dd>This calling convention (the default if no other calling convention is
642 specified) matches the target C calling conventions. This calling convention
643 supports varargs function calls and tolerates some mismatch in the declared
644 prototype and implemented declaration of the function (as does normal C).
645 </dd>
646
647 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
648
649 <dd>This calling convention attempts to make calls as fast as possible
650 (e.g. by passing things in registers). This calling convention allows the
651 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]652 without having to conform to an externally specified ABI (Application Binary
653 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]654 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
655 supported. This calling convention does not support varargs and requires the
656 prototype of all callees to exactly match the prototype of the function
657 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]658 </dd>
659
660 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
661
662 <dd>This calling convention attempts to make code in the caller as efficient
663 as possible under the assumption that the call is not commonly executed. As
664 such, these calls often preserve all registers so that the call does not break
665 any live ranges in the caller side. This calling convention does not support
666 varargs and requires the prototype of all callees to exactly match the
667 prototype of the function definition.
668 </dd>
669
670 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
671
672 <dd>Any calling convention may be specified by number, allowing
673 target-specific calling conventions to be used. Target specific calling
674 conventions start at 64.
675 </dd>
676</dl>
677
678<p>More calling conventions can be added/defined on an as-needed basis, to
679support pascal conventions or any other well-known target-independent
680convention.</p>
681
682</div>
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
686 <a name="visibility">Visibility Styles</a>
687</div>
688
689<div class="doc_text">
690
691<p>
692All Global Variables and Functions have one of the following visibility styles:
693</p>
694
695<dl>
696 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
697
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]698 <dd>On targets that use the ELF object file format, default visibility means
699 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]700 modules and, in shared libraries, means that the declared entity may be
701 overridden. On Darwin, default visibility means that the declaration is
702 visible to other modules. Default visibility corresponds to "external
703 linkage" in the language.
704 </dd>
705
706 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
707
708 <dd>Two declarations of an object with hidden visibility refer to the same
709 object if they are in the same shared object. Usually, hidden visibility
710 indicates that the symbol will not be placed into the dynamic symbol table,
711 so no other module (executable or shared library) can reference it
712 directly.
713 </dd>
714
715 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
716
717 <dd>On ELF, protected visibility indicates that the symbol will be placed in
718 the dynamic symbol table, but that references within the defining module will
719 bind to the local symbol. That is, the symbol cannot be overridden by another
720 module.
721 </dd>
722</dl>
723
724</div>
725
726<!-- ======================================================================= -->
727<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]728 <a name="namedtypes">Named Types</a>
729</div>
730
731<div class="doc_text">
732
733<p>LLVM IR allows you to specify name aliases for certain types. This can make
734it easier to read the IR and make the IR more condensed (particularly when
735recursive types are involved). An example of a name specification is:
736</p>
737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
744<p>You may give a name to any <a href="#typesystem">type</a> except "<a
745href="t_void">void</a>". Type name aliases may be used anywhere a type is
746expected with the syntax "%mytype".</p>
747
748<p>Note that type names are aliases for the structural type that they indicate,
749and that you can therefore specify multiple names for the same type. This often
750leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
751structural typing, the name is not part of the type. When printing out LLVM IR,
752the printer will pick <em>one name</em> to render all types of a particular
753shape. This means that if you have code where two different source types end up
754having the same LLVM type, that the dumper will sometimes print the "wrong" or
755unexpected type. This is an important design point and isn't going to
756change.</p>
757
758</div>
759
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]760<!-- ======================================================================= -->
761<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
767<p>Global variables define regions of memory allocated at compilation time
768instead of run-time. Global variables may optionally be initialized, may have
769an explicit section to be placed in, and may have an optional explicit alignment
770specified. A variable may be defined as "thread_local", which means that it
771will not be shared by threads (each thread will have a separated copy of the
772variable). A variable may be defined as a global "constant," which indicates
773that the contents of the variable will <b>never</b> be modified (enabling better
774optimization, allowing the global data to be placed in the read-only section of
775an executable, etc). Note that variables that need runtime initialization
776cannot be marked "constant" as there is a store to the variable.</p>
777
778<p>
779LLVM explicitly allows <em>declarations</em> of global variables to be marked
780constant, even if the final definition of the global is not. This capability
781can be used to enable slightly better optimization of the program, but requires
782the language definition to guarantee that optimizations based on the
783'constantness' are valid for the translation units that do not include the
784definition.
785</p>
786
787<p>As SSA values, global variables define pointer values that are in
788scope (i.e. they dominate) all basic blocks in the program. Global
789variables always define a pointer to their "content" type because they
790describe a region of memory, and all memory objects in LLVM are
791accessed through pointers.</p>
792
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]793<p>A global variable may be declared to reside in a target-specifc numbered
794address space. For targets that support them, address spaces may affect how
795optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]796the variable. The default address space is zero. The address space qualifier
797must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]799<p>LLVM allows an explicit section to be specified for globals. If the target
800supports it, it will emit globals to the section specified.</p>
801
802<p>An explicit alignment may be specified for a global. If not present, or if
803the alignment is set to zero, the alignment of the global is set by the target
804to whatever it feels convenient. If an explicit alignment is specified, the
805global is forced to have at least that much alignment. All alignments must be
806a power of 2.</p>
807
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]808<p>For example, the following defines a global in a numbered address space with
809an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]810
811<div class="doc_code">
812<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]813@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814</pre>
815</div>
816
817</div>
818
819
820<!-- ======================================================================= -->
821<div class="doc_subsection">
822 <a name="functionstructure">Functions</a>
823</div>
824
825<div class="doc_text">
826
827<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
828an optional <a href="#linkage">linkage type</a>, an optional
829<a href="#visibility">visibility style</a>, an optional
830<a href="#callingconv">calling convention</a>, a return type, an optional
831<a href="#paramattrs">parameter attribute</a> for the return type, a function
832name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]833<a href="#paramattrs">parameter attributes</a>), optional
834<a href="#fnattrs">function attributes</a>, an optional section,
835an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]836an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
838LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
839optional <a href="#linkage">linkage type</a>, an optional
840<a href="#visibility">visibility style</a>, an optional
841<a href="#callingconv">calling convention</a>, a return type, an optional
842<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]843name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]844<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]845
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]846<p>A function definition contains a list of basic blocks, forming the CFG
847(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]848the function. Each basic block may optionally start with a label (giving the
849basic block a symbol table entry), contains a list of instructions, and ends
850with a <a href="#terminators">terminator</a> instruction (such as a branch or
851function return).</p>
852
853<p>The first basic block in a function is special in two ways: it is immediately
854executed on entrance to the function, and it is not allowed to have predecessor
855basic blocks (i.e. there can not be any branches to the entry block of a
856function). Because the block can have no predecessors, it also cannot have any
857<a href="#i_phi">PHI nodes</a>.</p>
858
859<p>LLVM allows an explicit section to be specified for functions. If the target
860supports it, it will emit functions to the section specified.</p>
861
862<p>An explicit alignment may be specified for a function. If not present, or if
863the alignment is set to zero, the alignment of the function is set by the target
864to whatever it feels convenient. If an explicit alignment is specified, the
865function is forced to have at least that much alignment. All alignments must be
866a power of 2.</p>
867
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]868 <h5>Syntax:</h5>
869
870<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]871<tt>
872define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
873 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
874 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
875 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
876 [<a href="#gc">gc</a>] { ... }
877</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]878</div>
879
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]880</div>
881
882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
885 <a name="aliasstructure">Aliases</a>
886</div>
887<div class="doc_text">
888 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]889 function, global variable, another alias or bitcast of global value). Aliases
890 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]891 optional <a href="#visibility">visibility style</a>.</p>
892
893 <h5>Syntax:</h5>
894
895<div class="doc_code">
896<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]897@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]898</pre>
899</div>
900
901</div>
902
903
904
905<!-- ======================================================================= -->
906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
907<div class="doc_text">
908 <p>The return type and each parameter of a function type may have a set of
909 <i>parameter attributes</i> associated with them. Parameter attributes are
910 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]911 a function. Parameter attributes are considered to be part of the function,
912 not of the function type, so functions with different parameter attributes
913 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]914
915 <p>Parameter attributes are simple keywords that follow the type specified. If
916 multiple parameter attributes are needed, they are space separated. For
917 example:</p>
918
919<div class="doc_code">
920<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]921declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]922declare i32 @atoi(i8 zeroext)
923declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]924</pre>
925</div>
926
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]927 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
928 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]929
930 <p>Currently, only the following parameter attributes are defined:</p>
931 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]932 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]933 <dd>This indicates to the code generator that the parameter or return value
934 should be zero-extended to a 32-bit value by the caller (for a parameter)
935 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]936
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]937 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]938 <dd>This indicates to the code generator that the parameter or return value
939 should be sign-extended to a 32-bit value by the caller (for a parameter)
940 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]942 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]943 <dd>This indicates that this parameter or return value should be treated
944 in a special target-dependent fashion during while emitting code for a
945 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]946 to memory, though some targets use it to distinguish between two different
947 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]948
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]949 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]950 <dd>This indicates that the pointer parameter should really be passed by
951 value to the function. The attribute implies that a hidden copy of the
952 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]953 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]954 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]955 value, but is also valid on pointers to scalars. The copy is considered to
956 belong to the caller not the callee (for example,
957 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]958 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]959 values. The byval attribute also supports specifying an alignment with the
960 align attribute. This has a target-specific effect on the code generator
961 that usually indicates a desired alignment for the synthesized stack
962 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]963
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]964 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]965 <dd>This indicates that the pointer parameter specifies the address of a
966 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]967 This pointer must be guaranteed by the caller to be valid: loads and stores
968 to the structure may be assumed by the callee to not to trap. This may only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]969 be applied to the first parameter. This is not a valid attribute for
970 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]972 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]973 <dd>This indicates that the pointer does not alias any global or any other
974 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]975 case. On a function return value, <tt>noalias</tt> additionally indicates
976 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]977 caller. For further details, please see the discussion of the NoAlias
978 response in
979 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
980 analysis</a>.</dd>
981
982 <dt><tt>nocapture</tt></dt>
983 <dd>This indicates that the callee does not make any copies of the pointer
984 that outlive the callee itself. This is not a valid attribute for return
985 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]986
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]987 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]988 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]989 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
990 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]991 </dl>
992
993</div>
994
995<!-- ======================================================================= -->
996<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]997 <a name="gc">Garbage Collector Names</a>
998</div>
999
1000<div class="doc_text">
1001<p>Each function may specify a garbage collector name, which is simply a
1002string.</p>
1003
1004<div class="doc_code"><pre
1005>define void @f() gc "name" { ...</pre></div>
1006
1007<p>The compiler declares the supported values of <i>name</i>. Specifying a
1008collector which will cause the compiler to alter its output in order to support
1009the named garbage collection algorithm.</p>
1010</div>
1011
1012<!-- ======================================================================= -->
1013<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1014 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1015</div>
1016
1017<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1018
1019<p>Function attributes are set to communicate additional information about
1020 a function. Function attributes are considered to be part of the function,
1021 not of the function type, so functions with different parameter attributes
1022 can have the same function type.</p>
1023
1024 <p>Function attributes are simple keywords that follow the type specified. If
1025 multiple attributes are needed, they are space separated. For
1026 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1027
1028<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1029<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1030define void @f() noinline { ... }
1031define void @f() alwaysinline { ... }
1032define void @f() alwaysinline optsize { ... }
1033define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1034</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1035</div>
1036
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1037<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1038<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1039<dd>This attribute indicates that the inliner should attempt to inline this
1040function into callers whenever possible, ignoring any active inlining size
1041threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1042
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1043<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1044<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1045in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1046<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1047
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1048<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1049<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1050make choices that keep the code size of this function low, and otherwise do
1051optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1052
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1053<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1054<dd>This function attribute indicates that the function never returns normally.
1055This produces undefined behavior at runtime if the function ever does
1056dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1057
1058<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1059<dd>This function attribute indicates that the function never returns with an
1060unwind or exceptional control flow. If the function does unwind, its runtime
1061behavior is undefined.</dd>
1062
1063<dt><tt>readnone</tt></dt>
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1064<dd>This attribute indicates that the function computes its result (or decides to
1065unwind an exception) based strictly on its arguments, without dereferencing any
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1066pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1067registers, etc) visible to caller functions. It does not write through any
1068pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1069never changes any state visible to callers. This means that it cannot unwind
1070exceptions by calling the <tt>C++</tt> exception throwing methods, but could
1071use the <tt>unwind</tt> instruction.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1072
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1073<dt><tt><a name="readonly">readonly</a></tt></dt>
1074<dd>This attribute indicates that the function does not write through any
1075pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1076or otherwise modify any state (e.g. memory, control registers, etc) visible to
1077caller functions. It may dereference pointer arguments and read state that may
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1078be set in the caller. A readonly function always returns the same value (or
1079unwinds an exception identically) when called with the same set of arguments
1080and global state. It cannot unwind an exception by calling the <tt>C++</tt>
1081exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1082
1083<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1084<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1085protector. It is in the form of a "canary"&mdash;a random value placed on the
1086stack before the local variables that's checked upon return from the function to
1087see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1088needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1089
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1090<br><br>If a function that has an <tt>ssp</tt> attribute is inlined into a function
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1091that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1092have an <tt>ssp</tt> attribute.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1093
1094<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1095<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1096stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1097function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1098
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1099If a function that has an <tt>sspreq</tt> attribute is inlined into a
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1100function that doesn't have an <tt>sspreq</tt> attribute or which has
1101an <tt>ssp</tt> attribute, then the resulting function will have
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1102an <tt>sspreq</tt> attribute.</dd>
1103
1104<dt><tt>noredzone</tt></dt>
Dan Gohman06c9b732009-06-15 17:37:09 +0000[diff] [blame]1105<dd>This attribute indicates that the code generator should not use a
Dan Gohmanf958d5c2009-06-15 21:18:01 +0000[diff] [blame]1106red zone, even if the target-specific ABI normally permits it.
Dan Gohman06c9b732009-06-15 17:37:09 +0000[diff] [blame]1107</dd>
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame]1108
1109<dt><tt>noimplicitfloat</tt></dt>
1110<dd>This attributes disables implicit floating point instructions.</dd>
1111
Anton Korobeynikovedd7d112009-07-17 18:07:26 +0000[diff] [blame^]1112<dt><tt>naked</tt></dt>
1113<dd>This attribute disables prologue / epilogue emission for the function</dd>
1114
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1115</dl>
1116
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1117</div>
1118
1119<!-- ======================================================================= -->
1120<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1121 <a name="moduleasm">Module-Level Inline Assembly</a>
1122</div>
1123
1124<div class="doc_text">
1125<p>
1126Modules may contain "module-level inline asm" blocks, which corresponds to the
1127GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1128LLVM and treated as a single unit, but may be separated in the .ll file if
1129desired. The syntax is very simple:
1130</p>
1131
1132<div class="doc_code">
1133<pre>
1134module asm "inline asm code goes here"
1135module asm "more can go here"
1136</pre>
1137</div>
1138
1139<p>The strings can contain any character by escaping non-printable characters.
1140 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1141 for the number.
1142</p>
1143
1144<p>
1145 The inline asm code is simply printed to the machine code .s file when
1146 assembly code is generated.
1147</p>
1148</div>
1149
1150<!-- ======================================================================= -->
1151<div class="doc_subsection">
1152 <a name="datalayout">Data Layout</a>
1153</div>
1154
1155<div class="doc_text">
1156<p>A module may specify a target specific data layout string that specifies how
1157data is to be laid out in memory. The syntax for the data layout is simply:</p>
1158<pre> target datalayout = "<i>layout specification</i>"</pre>
1159<p>The <i>layout specification</i> consists of a list of specifications
1160separated by the minus sign character ('-'). Each specification starts with a
1161letter and may include other information after the letter to define some
1162aspect of the data layout. The specifications accepted are as follows: </p>
1163<dl>
1164 <dt><tt>E</tt></dt>
1165 <dd>Specifies that the target lays out data in big-endian form. That is, the
1166 bits with the most significance have the lowest address location.</dd>
1167 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1168 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1169 the bits with the least significance have the lowest address location.</dd>
1170 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1171 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1172 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1173 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1174 too.</dd>
1175 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1176 <dd>This specifies the alignment for an integer type of a given bit
1177 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1178 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1179 <dd>This specifies the alignment for a vector type of a given bit
1180 <i>size</i>.</dd>
1181 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1182 <dd>This specifies the alignment for a floating point type of a given bit
1183 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1184 (double).</dd>
1185 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1186 <dd>This specifies the alignment for an aggregate type of a given bit
1187 <i>size</i>.</dd>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1188 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1189 <dd>This specifies the alignment for a stack object of a given bit
1190 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1191</dl>
1192<p>When constructing the data layout for a given target, LLVM starts with a
1193default set of specifications which are then (possibly) overriden by the
1194specifications in the <tt>datalayout</tt> keyword. The default specifications
1195are given in this list:</p>
1196<ul>
1197 <li><tt>E</tt> - big endian</li>
1198 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1199 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1200 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1201 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1202 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1203 <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]1204 alignment of 64-bits</li>
1205 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1206 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1207 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1208 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1209 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1210 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1211</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1212<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1213following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1214<ol>
1215 <li>If the type sought is an exact match for one of the specifications, that
1216 specification is used.</li>
1217 <li>If no match is found, and the type sought is an integer type, then the
1218 smallest integer type that is larger than the bitwidth of the sought type is
1219 used. If none of the specifications are larger than the bitwidth then the the
1220 largest integer type is used. For example, given the default specifications
1221 above, the i7 type will use the alignment of i8 (next largest) while both
1222 i65 and i256 will use the alignment of i64 (largest specified).</li>
1223 <li>If no match is found, and the type sought is a vector type, then the
1224 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1225 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1226 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227</ol>
1228</div>
1229
1230<!-- *********************************************************************** -->
1231<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1232<!-- *********************************************************************** -->
1233
1234<div class="doc_text">
1235
1236<p>The LLVM type system is one of the most important features of the
1237intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1238optimizations to be performed on the intermediate representation directly,
1239without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1240extra analyses on the side before the transformation. A strong type
1241system makes it easier to read the generated code and enables novel
1242analyses and transformations that are not feasible to perform on normal
1243three address code representations.</p>
1244
1245</div>
1246
1247<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1248<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1249Classifications</a> </div>
1250<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1251<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252classifications:</p>
1253
1254<table border="1" cellspacing="0" cellpadding="4">
1255 <tbody>
1256 <tr><th>Classification</th><th>Types</th></tr>
1257 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1258 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1260 </tr>
1261 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1262 <td><a href="#t_floating">floating point</a></td>
1263 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264 </tr>
1265 <tr>
1266 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1267 <td><a href="#t_integer">integer</a>,
1268 <a href="#t_floating">floating point</a>,
1269 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1270 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1271 <a href="#t_struct">structure</a>,
1272 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1273 <a href="#t_label">label</a>,
1274 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1275 </td>
1276 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1277 <tr>
1278 <td><a href="#t_primitive">primitive</a></td>
1279 <td><a href="#t_label">label</a>,
1280 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1281 <a href="#t_floating">floating point</a>,
1282 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1283 </tr>
1284 <tr>
1285 <td><a href="#t_derived">derived</a></td>
1286 <td><a href="#t_integer">integer</a>,
1287 <a href="#t_array">array</a>,
1288 <a href="#t_function">function</a>,
1289 <a href="#t_pointer">pointer</a>,
1290 <a href="#t_struct">structure</a>,
1291 <a href="#t_pstruct">packed structure</a>,
1292 <a href="#t_vector">vector</a>,
1293 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1294 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1295 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1296 </tbody>
1297</table>
1298
1299<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1300most important. Values of these types are the only ones which can be
1301produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1302instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1303</div>
1304
1305<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1306<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1307
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1308<div class="doc_text">
1309<p>The primitive types are the fundamental building blocks of the LLVM
1310system.</p>
1311
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1312</div>
1313
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1314<!-- _______________________________________________________________________ -->
1315<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1316
1317<div class="doc_text">
1318 <table>
1319 <tbody>
1320 <tr><th>Type</th><th>Description</th></tr>
1321 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1322 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1323 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1324 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1325 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1326 </tbody>
1327 </table>
1328</div>
1329
1330<!-- _______________________________________________________________________ -->
1331<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1332
1333<div class="doc_text">
1334<h5>Overview:</h5>
1335<p>The void type does not represent any value and has no size.</p>
1336
1337<h5>Syntax:</h5>
1338
1339<pre>
1340 void
1341</pre>
1342</div>
1343
1344<!-- _______________________________________________________________________ -->
1345<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1346
1347<div class="doc_text">
1348<h5>Overview:</h5>
1349<p>The label type represents code labels.</p>
1350
1351<h5>Syntax:</h5>
1352
1353<pre>
1354 label
1355</pre>
1356</div>
1357
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1358<!-- _______________________________________________________________________ -->
1359<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1360
1361<div class="doc_text">
1362<h5>Overview:</h5>
1363<p>The metadata type represents embedded metadata. The only derived type that
1364may contain metadata is <tt>metadata*</tt> or a function type that returns or
1365takes metadata typed parameters, but not pointer to metadata types.</p>
1366
1367<h5>Syntax:</h5>
1368
1369<pre>
1370 metadata
1371</pre>
1372</div>
1373
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1374
1375<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1376<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1377
1378<div class="doc_text">
1379
1380<p>The real power in LLVM comes from the derived types in the system.
1381This is what allows a programmer to represent arrays, functions,
1382pointers, and other useful types. Note that these derived types may be
1383recursive: For example, it is possible to have a two dimensional array.</p>
1384
1385</div>
1386
1387<!-- _______________________________________________________________________ -->
1388<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1389
1390<div class="doc_text">
1391
1392<h5>Overview:</h5>
1393<p>The integer type is a very simple derived type that simply specifies an
1394arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13952^23-1 (about 8 million) can be specified.</p>
1396
1397<h5>Syntax:</h5>
1398
1399<pre>
1400 iN
1401</pre>
1402
1403<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1404value.</p>
1405
1406<h5>Examples:</h5>
1407<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1408 <tr class="layout">
1409 <td class="left"><tt>i1</tt></td>
1410 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1411 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1412 <tr class="layout">
1413 <td class="left"><tt>i32</tt></td>
1414 <td class="left">a 32-bit integer.</td>
1415 </tr>
1416 <tr class="layout">
1417 <td class="left"><tt>i1942652</tt></td>
1418 <td class="left">a really big integer of over 1 million bits.</td>
1419 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1420</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1421
1422<p>Note that the code generator does not yet support large integer types
1423to be used as function return types. The specific limit on how large a
1424return type the code generator can currently handle is target-dependent;
1425currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1426targets.</p>
1427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1428</div>
1429
1430<!-- _______________________________________________________________________ -->
1431<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1432
1433<div class="doc_text">
1434
1435<h5>Overview:</h5>
1436
1437<p>The array type is a very simple derived type that arranges elements
1438sequentially in memory. The array type requires a size (number of
1439elements) and an underlying data type.</p>
1440
1441<h5>Syntax:</h5>
1442
1443<pre>
1444 [&lt;# elements&gt; x &lt;elementtype&gt;]
1445</pre>
1446
1447<p>The number of elements is a constant integer value; elementtype may
1448be any type with a size.</p>
1449
1450<h5>Examples:</h5>
1451<table class="layout">
1452 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1453 <td class="left"><tt>[40 x i32]</tt></td>
1454 <td class="left">Array of 40 32-bit integer values.</td>
1455 </tr>
1456 <tr class="layout">
1457 <td class="left"><tt>[41 x i32]</tt></td>
1458 <td class="left">Array of 41 32-bit integer values.</td>
1459 </tr>
1460 <tr class="layout">
1461 <td class="left"><tt>[4 x i8]</tt></td>
1462 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1463 </tr>
1464</table>
1465<p>Here are some examples of multidimensional arrays:</p>
1466<table class="layout">
1467 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1468 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1469 <td class="left">3x4 array of 32-bit integer values.</td>
1470 </tr>
1471 <tr class="layout">
1472 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1473 <td class="left">12x10 array of single precision floating point values.</td>
1474 </tr>
1475 <tr class="layout">
1476 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1477 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1478 </tr>
1479</table>
1480
1481<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1482length array. Normally, accesses past the end of an array are undefined in
1483LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1484As a special case, however, zero length arrays are recognized to be variable
1485length. This allows implementation of 'pascal style arrays' with the LLVM
1486type "{ i32, [0 x float]}", for example.</p>
1487
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1488<p>Note that the code generator does not yet support large aggregate types
1489to be used as function return types. The specific limit on how large an
1490aggregate return type the code generator can currently handle is
1491target-dependent, and also dependent on the aggregate element types.</p>
1492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1493</div>
1494
1495<!-- _______________________________________________________________________ -->
1496<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1497<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1499<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1501<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1502consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1503return type of a function type is a scalar type, a void type, or a struct type.
Devang Pateld5404c02008-03-24 20:52:42 +0000[diff] [blame]1504If the return type is a struct type then all struct elements must be of first
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1505class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1507<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1508
1509<pre>
1510 &lt;returntype list&gt; (&lt;parameter list&gt;)
1511</pre>
1512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1513<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1514specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1515which indicates that the function takes a variable number of arguments.
1516Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1517 href="#int_varargs">variable argument handling intrinsic</a> functions.
1518'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1519<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1521<h5>Examples:</h5>
1522<table class="layout">
1523 <tr class="layout">
1524 <td class="left"><tt>i32 (i32)</tt></td>
1525 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1526 </td>
1527 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1528 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1529 </tt></td>
1530 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1531 an <tt>i16</tt> that should be sign extended and a
1532 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1533 <tt>float</tt>.
1534 </td>
1535 </tr><tr class="layout">
1536 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1537 <td class="left">A vararg function that takes at least one
1538 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1539 which returns an integer. This is the signature for <tt>printf</tt> in
1540 LLVM.
1541 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1542 </tr><tr class="layout">
1543 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1544 <td class="left">A function taking an <tt>i32</tt>, returning two
1545 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1546 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547 </tr>
1548</table>
1549
1550</div>
1551<!-- _______________________________________________________________________ -->
1552<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1553<div class="doc_text">
1554<h5>Overview:</h5>
1555<p>The structure type is used to represent a collection of data members
1556together in memory. The packing of the field types is defined to match
1557the ABI of the underlying processor. The elements of a structure may
1558be any type that has a size.</p>
1559<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1560and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1561field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1562instruction.</p>
1563<h5>Syntax:</h5>
1564<pre> { &lt;type list&gt; }<br></pre>
1565<h5>Examples:</h5>
1566<table class="layout">
1567 <tr class="layout">
1568 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1569 <td class="left">A triple of three <tt>i32</tt> values</td>
1570 </tr><tr class="layout">
1571 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1572 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1573 second element is a <a href="#t_pointer">pointer</a> to a
1574 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1575 an <tt>i32</tt>.</td>
1576 </tr>
1577</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1578
1579<p>Note that the code generator does not yet support large aggregate types
1580to be used as function return types. The specific limit on how large an
1581aggregate return type the code generator can currently handle is
1582target-dependent, and also dependent on the aggregate element types.</p>
1583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1584</div>
1585
1586<!-- _______________________________________________________________________ -->
1587<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1588</div>
1589<div class="doc_text">
1590<h5>Overview:</h5>
1591<p>The packed structure type is used to represent a collection of data members
1592together in memory. There is no padding between fields. Further, the alignment
1593of a packed structure is 1 byte. The elements of a packed structure may
1594be any type that has a size.</p>
1595<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1596and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1597field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1598instruction.</p>
1599<h5>Syntax:</h5>
1600<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1601<h5>Examples:</h5>
1602<table class="layout">
1603 <tr class="layout">
1604 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1605 <td class="left">A triple of three <tt>i32</tt> values</td>
1606 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1607 <td class="left">
1608<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1609 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1610 second element is a <a href="#t_pointer">pointer</a> to a
1611 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1612 an <tt>i32</tt>.</td>
1613 </tr>
1614</table>
1615</div>
1616
1617<!-- _______________________________________________________________________ -->
1618<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1619<div class="doc_text">
1620<h5>Overview:</h5>
1621<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1622reference to another object, which must live in memory. Pointer types may have
1623an optional address space attribute defining the target-specific numbered
1624address space where the pointed-to object resides. The default address space is
1625zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1626
1627<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does
Chris Lattner0d879e02009-02-08 22:21:28 +0000[diff] [blame]1628it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630<h5>Syntax:</h5>
1631<pre> &lt;type&gt; *<br></pre>
1632<h5>Examples:</h5>
1633<table class="layout">
1634 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1635 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1636 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1637 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1638 </tr>
1639 <tr class="layout">
1640 <td class="left"><tt>i32 (i32 *) *</tt></td>
1641 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1643 <tt>i32</tt>.</td>
1644 </tr>
1645 <tr class="layout">
1646 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1647 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1648 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649 </tr>
1650</table>
1651</div>
1652
1653<!-- _______________________________________________________________________ -->
1654<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1655<div class="doc_text">
1656
1657<h5>Overview:</h5>
1658
1659<p>A vector type is a simple derived type that represents a vector
1660of elements. Vector types are used when multiple primitive data
1661are operated in parallel using a single instruction (SIMD).
1662A vector type requires a size (number of
1663elements) and an underlying primitive data type. Vectors must have a power
1664of two length (1, 2, 4, 8, 16 ...). Vector types are
1665considered <a href="#t_firstclass">first class</a>.</p>
1666
1667<h5>Syntax:</h5>
1668
1669<pre>
1670 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1671</pre>
1672
1673<p>The number of elements is a constant integer value; elementtype may
1674be any integer or floating point type.</p>
1675
1676<h5>Examples:</h5>
1677
1678<table class="layout">
1679 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1680 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1681 <td class="left">Vector of 4 32-bit integer values.</td>
1682 </tr>
1683 <tr class="layout">
1684 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1685 <td class="left">Vector of 8 32-bit floating-point values.</td>
1686 </tr>
1687 <tr class="layout">
1688 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1689 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1690 </tr>
1691</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1692
1693<p>Note that the code generator does not yet support large vector types
1694to be used as function return types. The specific limit on how large a
1695vector return type codegen can currently handle is target-dependent;
1696currently it's often a few times longer than a hardware vector register.</p>
1697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1698</div>
1699
1700<!-- _______________________________________________________________________ -->
1701<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1702<div class="doc_text">
1703
1704<h5>Overview:</h5>
1705
1706<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1707corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1708In LLVM, opaque types can eventually be resolved to any type (not just a
1709structure type).</p>
1710
1711<h5>Syntax:</h5>
1712
1713<pre>
1714 opaque
1715</pre>
1716
1717<h5>Examples:</h5>
1718
1719<table class="layout">
1720 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1721 <td class="left"><tt>opaque</tt></td>
1722 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1723 </tr>
1724</table>
1725</div>
1726
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1727<!-- ======================================================================= -->
1728<div class="doc_subsection">
1729 <a name="t_uprefs">Type Up-references</a>
1730</div>
1731
1732<div class="doc_text">
1733<h5>Overview:</h5>
1734<p>
1735An "up reference" allows you to refer to a lexically enclosing type without
1736requiring it to have a name. For instance, a structure declaration may contain a
1737pointer to any of the types it is lexically a member of. Example of up
1738references (with their equivalent as named type declarations) include:</p>
1739
1740<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1741 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1742 { \2 }* %y = type { %y }*
1743 \1* %z = type %z*
1744</pre>
1745
1746<p>
1747An up reference is needed by the asmprinter for printing out cyclic types when
1748there is no declared name for a type in the cycle. Because the asmprinter does
1749not want to print out an infinite type string, it needs a syntax to handle
1750recursive types that have no names (all names are optional in llvm IR).
1751</p>
1752
1753<h5>Syntax:</h5>
1754<pre>
1755 \&lt;level&gt;
1756</pre>
1757
1758<p>
1759The level is the count of the lexical type that is being referred to.
1760</p>
1761
1762<h5>Examples:</h5>
1763
1764<table class="layout">
1765 <tr class="layout">
1766 <td class="left"><tt>\1*</tt></td>
1767 <td class="left">Self-referential pointer.</td>
1768 </tr>
1769 <tr class="layout">
1770 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1771 <td class="left">Recursive structure where the upref refers to the out-most
1772 structure.</td>
1773 </tr>
1774</table>
1775</div>
1776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777
1778<!-- *********************************************************************** -->
1779<div class="doc_section"> <a name="constants">Constants</a> </div>
1780<!-- *********************************************************************** -->
1781
1782<div class="doc_text">
1783
1784<p>LLVM has several different basic types of constants. This section describes
1785them all and their syntax.</p>
1786
1787</div>
1788
1789<!-- ======================================================================= -->
1790<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1791
1792<div class="doc_text">
1793
1794<dl>
1795 <dt><b>Boolean constants</b></dt>
1796
1797 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1798 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1799 </dd>
1800
1801 <dt><b>Integer constants</b></dt>
1802
1803 <dd>Standard integers (such as '4') are constants of the <a
1804 href="#t_integer">integer</a> type. Negative numbers may be used with
1805 integer types.
1806 </dd>
1807
1808 <dt><b>Floating point constants</b></dt>
1809
1810 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1811 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1812 notation (see below). The assembler requires the exact decimal value of
1813 a floating-point constant. For example, the assembler accepts 1.25 but
1814 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1815 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1816
1817 <dt><b>Null pointer constants</b></dt>
1818
1819 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1820 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1821
1822</dl>
1823
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1824<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825of floating point constants. For example, the form '<tt>double
18260x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
18274.5e+15</tt>'. The only time hexadecimal floating point constants are required
1828(and the only time that they are generated by the disassembler) is when a
1829floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1830decimal floating point number in a reasonable number of digits. For example,
1831NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1832special values are represented in their IEEE hexadecimal format so that
1833assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1834<p>When using the hexadecimal form, constants of types float and double are
1835represented using the 16-digit form shown above (which matches the IEEE754
1836representation for double); float values must, however, be exactly representable
1837as IEE754 single precision.
1838Hexadecimal format is always used for long
1839double, and there are three forms of long double. The 80-bit
1840format used by x86 is represented as <tt>0xK</tt>
1841followed by 20 hexadecimal digits.
1842The 128-bit format used by PowerPC (two adjacent doubles) is represented
1843by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1844format is represented
1845by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1846target uses this format. Long doubles will only work if they match
1847the long double format on your target. All hexadecimal formats are big-endian
1848(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1849</div>
1850
1851<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1852<div class="doc_subsection">
1853<a name="aggregateconstants"> <!-- old anchor -->
1854<a name="complexconstants">Complex Constants</a></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1855</div>
1856
1857<div class="doc_text">
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1858<p>Complex constants are a (potentially recursive) combination of simple
1859constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1860
1861<dl>
1862 <dt><b>Structure constants</b></dt>
1863
1864 <dd>Structure constants are represented with notation similar to structure
1865 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1866 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1867 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1868 must have <a href="#t_struct">structure type</a>, and the number and
1869 types of elements must match those specified by the type.
1870 </dd>
1871
1872 <dt><b>Array constants</b></dt>
1873
1874 <dd>Array constants are represented with notation similar to array type
1875 definitions (a comma separated list of elements, surrounded by square brackets
1876 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1877 constants must have <a href="#t_array">array type</a>, and the number and
1878 types of elements must match those specified by the type.
1879 </dd>
1880
1881 <dt><b>Vector constants</b></dt>
1882
1883 <dd>Vector constants are represented with notation similar to vector type
1884 definitions (a comma separated list of elements, surrounded by
1885 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1886 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1887 href="#t_vector">vector type</a>, and the number and types of elements must
1888 match those specified by the type.
1889 </dd>
1890
1891 <dt><b>Zero initialization</b></dt>
1892
1893 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1894 value to zero of <em>any</em> type, including scalar and aggregate types.
1895 This is often used to avoid having to print large zero initializers (e.g. for
1896 large arrays) and is always exactly equivalent to using explicit zero
1897 initializers.
1898 </dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1899
1900 <dt><b>Metadata node</b></dt>
1901
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1902 <dd>A metadata node is a structure-like constant with
1903 <a href="#t_metadata">metadata type</a>. For example:
1904 "<tt>metadata !{ i32 0, metadata !"test" }</tt>". Unlike other constants
1905 that are meant to be interpreted as part of the instruction stream, metadata
1906 is a place to attach additional information such as debug info.
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1907 </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1908</dl>
1909
1910</div>
1911
1912<!-- ======================================================================= -->
1913<div class="doc_subsection">
1914 <a name="globalconstants">Global Variable and Function Addresses</a>
1915</div>
1916
1917<div class="doc_text">
1918
1919<p>The addresses of <a href="#globalvars">global variables</a> and <a
1920href="#functionstructure">functions</a> are always implicitly valid (link-time)
1921constants. These constants are explicitly referenced when the <a
1922href="#identifiers">identifier for the global</a> is used and always have <a
1923href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1924file:</p>
1925
1926<div class="doc_code">
1927<pre>
1928@X = global i32 17
1929@Y = global i32 42
1930@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1931</pre>
1932</div>
1933
1934</div>
1935
1936<!-- ======================================================================= -->
1937<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1938<div class="doc_text">
1939 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1940 no specific value. Undefined values may be of any type and be used anywhere
1941 a constant is permitted.</p>
1942
1943 <p>Undefined values indicate to the compiler that the program is well defined
1944 no matter what value is used, giving the compiler more freedom to optimize.
1945 </p>
1946</div>
1947
1948<!-- ======================================================================= -->
1949<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1950</div>
1951
1952<div class="doc_text">
1953
1954<p>Constant expressions are used to allow expressions involving other constants
1955to be used as constants. Constant expressions may be of any <a
1956href="#t_firstclass">first class</a> type and may involve any LLVM operation
1957that does not have side effects (e.g. load and call are not supported). The
1958following is the syntax for constant expressions:</p>
1959
1960<dl>
1961 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1962 <dd>Truncate a constant to another type. The bit size of CST must be larger
1963 than the bit size of TYPE. Both types must be integers.</dd>
1964
1965 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1966 <dd>Zero extend a constant to another type. The bit size of CST must be
1967 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1968
1969 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1970 <dd>Sign extend a constant to another type. The bit size of CST must be
1971 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1972
1973 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1974 <dd>Truncate a floating point constant to another floating point type. The
1975 size of CST must be larger than the size of TYPE. Both types must be
1976 floating point.</dd>
1977
1978 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1979 <dd>Floating point extend a constant to another type. The size of CST must be
1980 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1981
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1982 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1984 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1985 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1986 of the same number of elements. If the value won't fit in the integer type,
1987 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988
1989 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1990 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1991 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1992 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1993 of the same number of elements. If the value won't fit in the integer type,
1994 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1995
1996 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1997 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1998 constant. TYPE must be a scalar or vector floating point type. CST must be of
1999 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
2000 of the same number of elements. If the value won't fit in the floating point
2001 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2002
2003 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2004 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]2005 constant. TYPE must be a scalar or vector floating point type. CST must be of
2006 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
2007 of the same number of elements. If the value won't fit in the floating point
2008 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2009
2010 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2011 <dd>Convert a pointer typed constant to the corresponding integer constant
2012 TYPE must be an integer type. CST must be of pointer type. The CST value is
2013 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
2014
2015 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
2016 <dd>Convert a integer constant to a pointer constant. TYPE must be a
2017 pointer type. CST must be of integer type. The CST value is zero extended,
2018 truncated, or unchanged to make it fit in a pointer size. This one is
2019 <i>really</i> dangerous!</dd>
2020
2021 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2022 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2023 are the same as those for the <a href="#i_bitcast">bitcast
2024 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2025
2026 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
2027
2028 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
2029 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2030 instruction, the index list may have zero or more indexes, which are required
2031 to make sense for the type of "CSTPTR".</dd>
2032
2033 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
2034
2035 <dd>Perform the <a href="#i_select">select operation</a> on
2036 constants.</dd>
2037
2038 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2039 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2040
2041 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2042 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2043
2044 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2045
2046 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2047 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2048
2049 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2050
2051 <dd>Perform the <a href="#i_insertelement">insertelement
2052 operation</a> on constants.</dd>
2053
2054
2055 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2056
2057 <dd>Perform the <a href="#i_shufflevector">shufflevector
2058 operation</a> on constants.</dd>
2059
2060 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2061
2062 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2063 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2064 binary</a> operations. The constraints on operands are the same as those for
2065 the corresponding instruction (e.g. no bitwise operations on floating point
2066 values are allowed).</dd>
2067</dl>
2068</div>
2069
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2070<!-- ======================================================================= -->
2071<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2072</div>
2073
2074<div class="doc_text">
2075
2076<p>Embedded metadata provides a way to attach arbitrary data to the
2077instruction stream without affecting the behaviour of the program. There are
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2078two metadata primitives, strings and nodes. All metadata has the
2079<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2080point ('<tt>!</tt>').
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2081</p>
2082
2083<p>A metadata string is a string surrounded by double quotes. It can contain
2084any character by escaping non-printable characters with "\xx" where "xx" is
2085the two digit hex code. For example: "<tt>!"test\00"</tt>".
2086</p>
2087
2088<p>Metadata nodes are represented with notation similar to structure constants
2089(a comma separated list of elements, surrounded by braces and preceeded by an
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2090exclamation point). For example: "<tt>!{ metadata !"test\00", i32 10}</tt>".
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2091</p>
2092
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2093<p>A metadata node will attempt to track changes to the values it holds. In
2094the event that a value is deleted, it will be replaced with a typeless
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2095"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2096
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2097<p>Optimizations may rely on metadata to provide additional information about
2098the program that isn't available in the instructions, or that isn't easily
2099computable. Similarly, the code generator may expect a certain metadata format
2100to be used to express debugging information.</p>
2101</div>
2102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2103<!-- *********************************************************************** -->
2104<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2105<!-- *********************************************************************** -->
2106
2107<!-- ======================================================================= -->
2108<div class="doc_subsection">
2109<a name="inlineasm">Inline Assembler Expressions</a>
2110</div>
2111
2112<div class="doc_text">
2113
2114<p>
2115LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2116Module-Level Inline Assembly</a>) through the use of a special value. This
2117value represents the inline assembler as a string (containing the instructions
2118to emit), a list of operand constraints (stored as a string), and a flag that
2119indicates whether or not the inline asm expression has side effects. An example
2120inline assembler expression is:
2121</p>
2122
2123<div class="doc_code">
2124<pre>
2125i32 (i32) asm "bswap $0", "=r,r"
2126</pre>
2127</div>
2128
2129<p>
2130Inline assembler expressions may <b>only</b> be used as the callee operand of
2131a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2132</p>
2133
2134<div class="doc_code">
2135<pre>
2136%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2137</pre>
2138</div>
2139
2140<p>
2141Inline asms with side effects not visible in the constraint list must be marked
2142as having side effects. This is done through the use of the
2143'<tt>sideeffect</tt>' keyword, like so:
2144</p>
2145
2146<div class="doc_code">
2147<pre>
2148call void asm sideeffect "eieio", ""()
2149</pre>
2150</div>
2151
2152<p>TODO: The format of the asm and constraints string still need to be
2153documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2154need to be documented). This is probably best done by reference to another
2155document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2156</p>
2157
2158</div>
2159
2160<!-- *********************************************************************** -->
2161<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2162<!-- *********************************************************************** -->
2163
2164<div class="doc_text">
2165
2166<p>The LLVM instruction set consists of several different
2167classifications of instructions: <a href="#terminators">terminator
2168instructions</a>, <a href="#binaryops">binary instructions</a>,
2169<a href="#bitwiseops">bitwise binary instructions</a>, <a
2170 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2171instructions</a>.</p>
2172
2173</div>
2174
2175<!-- ======================================================================= -->
2176<div class="doc_subsection"> <a name="terminators">Terminator
2177Instructions</a> </div>
2178
2179<div class="doc_text">
2180
2181<p>As mentioned <a href="#functionstructure">previously</a>, every
2182basic block in a program ends with a "Terminator" instruction, which
2183indicates which block should be executed after the current block is
2184finished. These terminator instructions typically yield a '<tt>void</tt>'
2185value: they produce control flow, not values (the one exception being
2186the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2187<p>There are six different terminator instructions: the '<a
2188 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2189instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2190the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2191 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2192 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2193
2194</div>
2195
2196<!-- _______________________________________________________________________ -->
2197<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2198Instruction</a> </div>
2199<div class="doc_text">
2200<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2201<pre>
2202 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]2203 ret void <i>; Return from void function</i>
2204</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2205
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2206<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2207
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2208<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2209optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2210<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2211returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2212control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2213
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2214<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2215
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2216<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2217the return value. The type of the return value must be a
2218'<a href="#t_firstclass">first class</a>' type.</p>
2219
2220<p>A function is not <a href="#wellformed">well formed</a> if
2221it it has a non-void return type and contains a '<tt>ret</tt>'
2222instruction with no return value or a return value with a type that
2223does not match its type, or if it has a void return type and contains
2224a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2226<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2228<p>When the '<tt>ret</tt>' instruction is executed, control flow
2229returns back to the calling function's context. If the caller is a "<a
2230 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2231the instruction after the call. If the caller was an "<a
2232 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2233at the beginning of the "normal" destination block. If the instruction
2234returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2235return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2236
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2237<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2238
2239<pre>
2240 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2241 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2242 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]2243</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2244
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2245<p>Note that the code generator does not yet fully support large
2246 return values. The specific sizes that are currently supported are
2247 dependent on the target. For integers, on 32-bit targets the limit
2248 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2249 For aggregate types, the current limits are dependent on the element
2250 types; for example targets are often limited to 2 total integer
2251 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2253</div>
2254<!-- _______________________________________________________________________ -->
2255<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2256<div class="doc_text">
2257<h5>Syntax:</h5>
2258<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2259</pre>
2260<h5>Overview:</h5>
2261<p>The '<tt>br</tt>' instruction is used to cause control flow to
2262transfer to a different basic block in the current function. There are
2263two forms of this instruction, corresponding to a conditional branch
2264and an unconditional branch.</p>
2265<h5>Arguments:</h5>
2266<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2267single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2268unconditional form of the '<tt>br</tt>' instruction takes a single
2269'<tt>label</tt>' value as a target.</p>
2270<h5>Semantics:</h5>
2271<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2272argument is evaluated. If the value is <tt>true</tt>, control flows
2273to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2274control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2275<h5>Example:</h5>
Chris Lattner95127832009-05-09 18:11:50 +0000[diff] [blame]2276<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2277 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2278</div>
2279<!-- _______________________________________________________________________ -->
2280<div class="doc_subsubsection">
2281 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2282</div>
2283
2284<div class="doc_text">
2285<h5>Syntax:</h5>
2286
2287<pre>
2288 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2289</pre>
2290
2291<h5>Overview:</h5>
2292
2293<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2294several different places. It is a generalization of the '<tt>br</tt>'
2295instruction, allowing a branch to occur to one of many possible
2296destinations.</p>
2297
2298
2299<h5>Arguments:</h5>
2300
2301<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2302comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2303an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2304table is not allowed to contain duplicate constant entries.</p>
2305
2306<h5>Semantics:</h5>
2307
2308<p>The <tt>switch</tt> instruction specifies a table of values and
2309destinations. When the '<tt>switch</tt>' instruction is executed, this
2310table is searched for the given value. If the value is found, control flow is
2311transfered to the corresponding destination; otherwise, control flow is
2312transfered to the default destination.</p>
2313
2314<h5>Implementation:</h5>
2315
2316<p>Depending on properties of the target machine and the particular
2317<tt>switch</tt> instruction, this instruction may be code generated in different
2318ways. For example, it could be generated as a series of chained conditional
2319branches or with a lookup table.</p>
2320
2321<h5>Example:</h5>
2322
2323<pre>
2324 <i>; Emulate a conditional br instruction</i>
2325 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2326 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2327
2328 <i>; Emulate an unconditional br instruction</i>
2329 switch i32 0, label %dest [ ]
2330
2331 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2332 switch i32 %val, label %otherwise [ i32 0, label %onzero
2333 i32 1, label %onone
2334 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2335</pre>
2336</div>
2337
2338<!-- _______________________________________________________________________ -->
2339<div class="doc_subsubsection">
2340 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2341</div>
2342
2343<div class="doc_text">
2344
2345<h5>Syntax:</h5>
2346
2347<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2348 &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]2349 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2350</pre>
2351
2352<h5>Overview:</h5>
2353
2354<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2355function, with the possibility of control flow transfer to either the
2356'<tt>normal</tt>' label or the
2357'<tt>exception</tt>' label. If the callee function returns with the
2358"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2359"normal" label. If the callee (or any indirect callees) returns with the "<a
2360href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2361continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2362
2363<h5>Arguments:</h5>
2364
2365<p>This instruction requires several arguments:</p>
2366
2367<ol>
2368 <li>
2369 The optional "cconv" marker indicates which <a href="#callingconv">calling
2370 convention</a> the call should use. If none is specified, the call defaults
2371 to using C calling conventions.
2372 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2373
2374 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2375 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2376 and '<tt>inreg</tt>' attributes are valid here.</li>
2377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2378 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2379 function value being invoked. In most cases, this is a direct function
2380 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2381 an arbitrary pointer to function value.
2382 </li>
2383
2384 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2385 function to be invoked. </li>
2386
2387 <li>'<tt>function args</tt>': argument list whose types match the function
2388 signature argument types. If the function signature indicates the function
2389 accepts a variable number of arguments, the extra arguments can be
2390 specified. </li>
2391
2392 <li>'<tt>normal label</tt>': the label reached when the called function
2393 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2394
2395 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2396 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2397
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2398 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2399 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2400 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2401</ol>
2402
2403<h5>Semantics:</h5>
2404
2405<p>This instruction is designed to operate as a standard '<tt><a
2406href="#i_call">call</a></tt>' instruction in most regards. The primary
2407difference is that it establishes an association with a label, which is used by
2408the runtime library to unwind the stack.</p>
2409
2410<p>This instruction is used in languages with destructors to ensure that proper
2411cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2412exception. Additionally, this is important for implementation of
2413'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2414
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]2415<p>For the purposes of the SSA form, the definition of the value
2416returned by the '<tt>invoke</tt>' instruction is deemed to occur on
2417the edge from the current block to the "normal" label. If the callee
2418unwinds then no return value is available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2420<h5>Example:</h5>
2421<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2422 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2423 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2424 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2425 unwind label %TestCleanup <i>; {i32}:retval set</i>
2426</pre>
2427</div>
2428
2429
2430<!-- _______________________________________________________________________ -->
2431
2432<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2433Instruction</a> </div>
2434
2435<div class="doc_text">
2436
2437<h5>Syntax:</h5>
2438<pre>
2439 unwind
2440</pre>
2441
2442<h5>Overview:</h5>
2443
2444<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2445at the first callee in the dynamic call stack which used an <a
2446href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2447primarily used to implement exception handling.</p>
2448
2449<h5>Semantics:</h5>
2450
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2451<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2452immediately halt. The dynamic call stack is then searched for the first <a
2453href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2454execution continues at the "exceptional" destination block specified by the
2455<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2456dynamic call chain, undefined behavior results.</p>
2457</div>
2458
2459<!-- _______________________________________________________________________ -->
2460
2461<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2462Instruction</a> </div>
2463
2464<div class="doc_text">
2465
2466<h5>Syntax:</h5>
2467<pre>
2468 unreachable
2469</pre>
2470
2471<h5>Overview:</h5>
2472
2473<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2474instruction is used to inform the optimizer that a particular portion of the
2475code is not reachable. This can be used to indicate that the code after a
2476no-return function cannot be reached, and other facts.</p>
2477
2478<h5>Semantics:</h5>
2479
2480<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2481</div>
2482
2483
2484
2485<!-- ======================================================================= -->
2486<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2487<div class="doc_text">
2488<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2489program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2490produce a single value. The operands might represent
2491multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2492The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2493<p>There are several different binary operators:</p>
2494</div>
2495<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2496<div class="doc_subsubsection">
2497 <a name="i_add">'<tt>add</tt>' Instruction</a>
2498</div>
2499
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2500<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2502<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2503
2504<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2505 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2510<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2513
2514<p>The two arguments to the '<tt>add</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2515 href="#t_integer">integer</a> or
2516 <a href="#t_vector">vector</a> of integer values. Both arguments must
2517 have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2520
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2521<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2522
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2523<p>If the sum has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2524mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2525the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2526
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2527<p>Because LLVM integers use a two's complement representation, this
2528instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2531
2532<pre>
2533 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2534</pre>
2535</div>
2536<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2537<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2538 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2539</div>
2540
2541<div class="doc_text">
2542
2543<h5>Syntax:</h5>
2544
2545<pre>
2546 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2547</pre>
2548
2549<h5>Overview:</h5>
2550
2551<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2552
2553<h5>Arguments:</h5>
2554
2555<p>The two arguments to the '<tt>fadd</tt>' instruction must be
2556<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2557floating point values. Both arguments must have identical types.</p>
2558
2559<h5>Semantics:</h5>
2560
2561<p>The value produced is the floating point sum of the two operands.</p>
2562
2563<h5>Example:</h5>
2564
2565<pre>
2566 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2567</pre>
2568</div>
2569<!-- _______________________________________________________________________ -->
2570<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2571 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2572</div>
2573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2574<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2577
2578<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2579 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2584<p>The '<tt>sub</tt>' instruction returns the difference of its two
2585operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2586
2587<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2588'<tt>neg</tt>' instruction present in most other intermediate
2589representations.</p>
2590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2592
2593<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2594 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2595 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2598
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2599<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2600
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2601<p>If the difference has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2602mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2603the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2604
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2605<p>Because LLVM integers use a two's complement representation, this
2606instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608<h5>Example:</h5>
2609<pre>
2610 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2611 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2612</pre>
2613</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2616<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2617 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2618</div>
2619
2620<div class="doc_text">
2621
2622<h5>Syntax:</h5>
2623
2624<pre>
2625 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2626</pre>
2627
2628<h5>Overview:</h5>
2629
2630<p>The '<tt>fsub</tt>' instruction returns the difference of its two
2631operands.</p>
2632
2633<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
2634'<tt>fneg</tt>' instruction present in most other intermediate
2635representations.</p>
2636
2637<h5>Arguments:</h5>
2638
2639<p>The two arguments to the '<tt>fsub</tt>' instruction must be <a
2640 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2641 of floating point values. Both arguments must have identical types.</p>
2642
2643<h5>Semantics:</h5>
2644
2645<p>The value produced is the floating point difference of the two operands.</p>
2646
2647<h5>Example:</h5>
2648<pre>
2649 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2650 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2651</pre>
2652</div>
2653
2654<!-- _______________________________________________________________________ -->
2655<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2656 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2657</div>
2658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2661<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2662<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663</pre>
2664<h5>Overview:</h5>
2665<p>The '<tt>mul</tt>' instruction returns the product of its two
2666operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2669
2670<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2671href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2672values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2674<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2675
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2676<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2677
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2678<p>If the result of the multiplication has unsigned overflow,
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2679the result returned is the mathematical result modulo
26802<sup>n</sup>, where n is the bit width of the result.</p>
2681<p>Because LLVM integers use a two's complement representation, and the
2682result is the same width as the operands, this instruction returns the
2683correct result for both signed and unsigned integers. If a full product
2684(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2685should be sign-extended or zero-extended as appropriate to the
2686width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2687<h5>Example:</h5>
2688<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2689</pre>
2690</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2692<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2693<div class="doc_subsubsection">
2694 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2695</div>
2696
2697<div class="doc_text">
2698
2699<h5>Syntax:</h5>
2700<pre> &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2701</pre>
2702<h5>Overview:</h5>
2703<p>The '<tt>fmul</tt>' instruction returns the product of its two
2704operands.</p>
2705
2706<h5>Arguments:</h5>
2707
2708<p>The two arguments to the '<tt>fmul</tt>' instruction must be
2709<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2710of floating point values. Both arguments must have identical types.</p>
2711
2712<h5>Semantics:</h5>
2713
2714<p>The value produced is the floating point product of the two operands.</p>
2715
2716<h5>Example:</h5>
2717<pre> &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
2718</pre>
2719</div>
2720
2721<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2722<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2723</a></div>
2724<div class="doc_text">
2725<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2726<pre> &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]2727</pre>
2728<h5>Overview:</h5>
2729<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2730operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2734<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2735<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2736values. Both arguments must have identical types.</p>
2737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2739
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2740<p>The value produced is the unsigned integer quotient of the two operands.</p>
2741<p>Note that unsigned integer division and signed integer division are distinct
2742operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2743<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744<h5>Example:</h5>
2745<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2746</pre>
2747</div>
2748<!-- _______________________________________________________________________ -->
2749<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2750</a> </div>
2751<div class="doc_text">
2752<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2753<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2754 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2755</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2758
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2759<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2760operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2762<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2763
2764<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2765<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2766values. Both arguments must have identical types.</p>
2767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2769<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2770<p>Note that signed integer division and unsigned integer division are distinct
2771operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2772<p>Division by zero leads to undefined behavior. Overflow also leads to
2773undefined behavior; this is a rare case, but can occur, for example,
2774by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2775<h5>Example:</h5>
2776<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2777</pre>
2778</div>
2779<!-- _______________________________________________________________________ -->
2780<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2781Instruction</a> </div>
2782<div class="doc_text">
2783<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2784<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2785 &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]2786</pre>
2787<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2788
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2789<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2790operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2795<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2796of floating point values. Both arguments must have identical types.</p>
2797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2800<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2801
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2802<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2803
2804<pre>
2805 &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]2806</pre>
2807</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809<!-- _______________________________________________________________________ -->
2810<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2811</div>
2812<div class="doc_text">
2813<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2814<pre> &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]2815</pre>
2816<h5>Overview:</h5>
2817<p>The '<tt>urem</tt>' instruction returns the remainder from the
2818unsigned division of its two arguments.</p>
2819<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2820<p>The two arguments to the '<tt>urem</tt>' instruction must be
2821<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2822values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2823<h5>Semantics:</h5>
2824<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2825This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2826<p>Note that unsigned integer remainder and signed integer remainder are
2827distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2828<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2829<h5>Example:</h5>
2830<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2831</pre>
2832
2833</div>
2834<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2835<div class="doc_subsubsection">
2836 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2837</div>
2838
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2839<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2842
2843<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2844 &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]2845</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2847<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2849<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2850signed division of its two operands. This instruction can also take
2851<a href="#t_vector">vector</a> versions of the values in which case
2852the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2856<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2857<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2858values. Both arguments must have identical types.</p>
2859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2860<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2863has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2864operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865a value. For more information about the difference, see <a
2866 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2867Math Forum</a>. For a table of how this is implemented in various languages,
2868please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2869Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2870<p>Note that signed integer remainder and unsigned integer remainder are
2871distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2872<p>Taking the remainder of a division by zero leads to undefined behavior.
2873Overflow also leads to undefined behavior; this is a rare case, but can occur,
2874for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2875(The remainder doesn't actually overflow, but this rule lets srem be
2876implemented using instructions that return both the result of the division
2877and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2878<h5>Example:</h5>
2879<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2880</pre>
2881
2882</div>
2883<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2884<div class="doc_subsubsection">
2885 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2886
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2887<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2889<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2890<pre> &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]2891</pre>
2892<h5>Overview:</h5>
2893<p>The '<tt>frem</tt>' instruction returns the remainder from the
2894division of its two operands.</p>
2895<h5>Arguments:</h5>
2896<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2897<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2898of floating point values. Both arguments must have identical types.</p>
2899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2900<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2901
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2902<p>This instruction returns the <i>remainder</i> of a division.
2903The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2905<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2906
2907<pre>
2908 &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]2909</pre>
2910</div>
2911
2912<!-- ======================================================================= -->
2913<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2914Operations</a> </div>
2915<div class="doc_text">
2916<p>Bitwise binary operators are used to do various forms of
2917bit-twiddling in a program. They are generally very efficient
2918instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2919instructions. They require two operands of the same type, execute an operation on them,
2920and produce a single value. The resulting value is the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2921</div>
2922
2923<!-- _______________________________________________________________________ -->
2924<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2925Instruction</a> </div>
2926<div class="doc_text">
2927<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2928<pre> &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]2929</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2931<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2932
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2933<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2934the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2936<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2937
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2938<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2939 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2940type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2943
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2944<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2945where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2946equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2947If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2948corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2950<h5>Example:</h5><pre>
2951 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2952 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2953 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2954 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2955 &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]2956</pre>
2957</div>
2958<!-- _______________________________________________________________________ -->
2959<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2960Instruction</a> </div>
2961<div class="doc_text">
2962<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2963<pre> &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]2964</pre>
2965
2966<h5>Overview:</h5>
2967<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2968operand shifted to the right a specified number of bits with zero fill.</p>
2969
2970<h5>Arguments:</h5>
2971<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2972<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2973type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2974
2975<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2977<p>This instruction always performs a logical shift right operation. The most
2978significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2979shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2980the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2981vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2982amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2983
2984<h5>Example:</h5>
2985<pre>
2986 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2987 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2988 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2989 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2990 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2991 &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]2992</pre>
2993</div>
2994
2995<!-- _______________________________________________________________________ -->
2996<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2997Instruction</a> </div>
2998<div class="doc_text">
2999
3000<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3001<pre> &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]3002</pre>
3003
3004<h5>Overview:</h5>
3005<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3006operand shifted to the right a specified number of bits with sign extension.</p>
3007
3008<h5>Arguments:</h5>
3009<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]3010<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3011type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3012
3013<h5>Semantics:</h5>
3014<p>This instruction always performs an arithmetic shift right operation,
3015The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3016of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]3017larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
3018arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
3019corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3020
3021<h5>Example:</h5>
3022<pre>
3023 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3024 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3025 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3026 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3027 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3028 &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]3029</pre>
3030</div>
3031
3032<!-- _______________________________________________________________________ -->
3033<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3034Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3035
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3036<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3037
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3038<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3039
3040<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3041 &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]3042</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3044<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3045
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3046<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
3047its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3050
3051<p>The two arguments to the '<tt>and</tt>' instruction must be
3052<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3053values. Both arguments must have identical types.</p>
3054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3055<h5>Semantics:</h5>
3056<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
3057<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3058<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3059<table border="1" cellspacing="0" cellpadding="4">
3060 <tbody>
3061 <tr>
3062 <td>In0</td>
3063 <td>In1</td>
3064 <td>Out</td>
3065 </tr>
3066 <tr>
3067 <td>0</td>
3068 <td>0</td>
3069 <td>0</td>
3070 </tr>
3071 <tr>
3072 <td>0</td>
3073 <td>1</td>
3074 <td>0</td>
3075 </tr>
3076 <tr>
3077 <td>1</td>
3078 <td>0</td>
3079 <td>0</td>
3080 </tr>
3081 <tr>
3082 <td>1</td>
3083 <td>1</td>
3084 <td>1</td>
3085 </tr>
3086 </tbody>
3087</table>
3088</div>
3089<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3090<pre>
3091 &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]3092 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3093 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3094</pre>
3095</div>
3096<!-- _______________________________________________________________________ -->
3097<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
3098<div class="doc_text">
3099<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3100<pre> &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3101</pre>
3102<h5>Overview:</h5>
3103<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
3104or of its two operands.</p>
3105<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3106
3107<p>The two arguments to the '<tt>or</tt>' instruction must be
3108<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3109values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3110<h5>Semantics:</h5>
3111<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
3112<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3113<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3114<table border="1" cellspacing="0" cellpadding="4">
3115 <tbody>
3116 <tr>
3117 <td>In0</td>
3118 <td>In1</td>
3119 <td>Out</td>
3120 </tr>
3121 <tr>
3122 <td>0</td>
3123 <td>0</td>
3124 <td>0</td>
3125 </tr>
3126 <tr>
3127 <td>0</td>
3128 <td>1</td>
3129 <td>1</td>
3130 </tr>
3131 <tr>
3132 <td>1</td>
3133 <td>0</td>
3134 <td>1</td>
3135 </tr>
3136 <tr>
3137 <td>1</td>
3138 <td>1</td>
3139 <td>1</td>
3140 </tr>
3141 </tbody>
3142</table>
3143</div>
3144<h5>Example:</h5>
3145<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3146 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3147 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3148</pre>
3149</div>
3150<!-- _______________________________________________________________________ -->
3151<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3152Instruction</a> </div>
3153<div class="doc_text">
3154<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3155<pre> &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]3156</pre>
3157<h5>Overview:</h5>
3158<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3159or of its two operands. The <tt>xor</tt> is used to implement the
3160"one's complement" operation, which is the "~" operator in C.</p>
3161<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3162<p>The two arguments to the '<tt>xor</tt>' instruction must be
3163<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3164values. Both arguments must have identical types.</p>
3165
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3166<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3167
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3168<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3169<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3170<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3171<table border="1" cellspacing="0" cellpadding="4">
3172 <tbody>
3173 <tr>
3174 <td>In0</td>
3175 <td>In1</td>
3176 <td>Out</td>
3177 </tr>
3178 <tr>
3179 <td>0</td>
3180 <td>0</td>
3181 <td>0</td>
3182 </tr>
3183 <tr>
3184 <td>0</td>
3185 <td>1</td>
3186 <td>1</td>
3187 </tr>
3188 <tr>
3189 <td>1</td>
3190 <td>0</td>
3191 <td>1</td>
3192 </tr>
3193 <tr>
3194 <td>1</td>
3195 <td>1</td>
3196 <td>0</td>
3197 </tr>
3198 </tbody>
3199</table>
3200</div>
3201<p> </p>
3202<h5>Example:</h5>
3203<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3204 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3205 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3206 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3207</pre>
3208</div>
3209
3210<!-- ======================================================================= -->
3211<div class="doc_subsection">
3212 <a name="vectorops">Vector Operations</a>
3213</div>
3214
3215<div class="doc_text">
3216
3217<p>LLVM supports several instructions to represent vector operations in a
3218target-independent manner. These instructions cover the element-access and
3219vector-specific operations needed to process vectors effectively. While LLVM
3220does directly support these vector operations, many sophisticated algorithms
3221will want to use target-specific intrinsics to take full advantage of a specific
3222target.</p>
3223
3224</div>
3225
3226<!-- _______________________________________________________________________ -->
3227<div class="doc_subsubsection">
3228 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3229</div>
3230
3231<div class="doc_text">
3232
3233<h5>Syntax:</h5>
3234
3235<pre>
3236 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3237</pre>
3238
3239<h5>Overview:</h5>
3240
3241<p>
3242The '<tt>extractelement</tt>' instruction extracts a single scalar
3243element from a vector at a specified index.
3244</p>
3245
3246
3247<h5>Arguments:</h5>
3248
3249<p>
3250The first operand of an '<tt>extractelement</tt>' instruction is a
3251value of <a href="#t_vector">vector</a> type. The second operand is
3252an index indicating the position from which to extract the element.
3253The index may be a variable.</p>
3254
3255<h5>Semantics:</h5>
3256
3257<p>
3258The result is a scalar of the same type as the element type of
3259<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3260<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3261results are undefined.
3262</p>
3263
3264<h5>Example:</h5>
3265
3266<pre>
3267 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3268</pre>
3269</div>
3270
3271
3272<!-- _______________________________________________________________________ -->
3273<div class="doc_subsubsection">
3274 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3275</div>
3276
3277<div class="doc_text">
3278
3279<h5>Syntax:</h5>
3280
3281<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3282 &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]3283</pre>
3284
3285<h5>Overview:</h5>
3286
3287<p>
3288The '<tt>insertelement</tt>' instruction inserts a scalar
3289element into a vector at a specified index.
3290</p>
3291
3292
3293<h5>Arguments:</h5>
3294
3295<p>
3296The first operand of an '<tt>insertelement</tt>' instruction is a
3297value of <a href="#t_vector">vector</a> type. The second operand is a
3298scalar value whose type must equal the element type of the first
3299operand. The third operand is an index indicating the position at
3300which to insert the value. The index may be a variable.</p>
3301
3302<h5>Semantics:</h5>
3303
3304<p>
3305The result is a vector of the same type as <tt>val</tt>. Its
3306element values are those of <tt>val</tt> except at position
3307<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3308exceeds the length of <tt>val</tt>, the results are undefined.
3309</p>
3310
3311<h5>Example:</h5>
3312
3313<pre>
3314 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3315</pre>
3316</div>
3317
3318<!-- _______________________________________________________________________ -->
3319<div class="doc_subsubsection">
3320 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3321</div>
3322
3323<div class="doc_text">
3324
3325<h5>Syntax:</h5>
3326
3327<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3328 &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]3329</pre>
3330
3331<h5>Overview:</h5>
3332
3333<p>
3334The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3335from two input vectors, returning a vector with the same element type as
3336the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3337</p>
3338
3339<h5>Arguments:</h5>
3340
3341<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3342The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3343with types that match each other. The third argument is a shuffle mask whose
3344element type is always 'i32'. The result of the instruction is a vector whose
3345length is the same as the shuffle mask and whose element type is the same as
3346the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3347</p>
3348
3349<p>
3350The shuffle mask operand is required to be a constant vector with either
3351constant integer or undef values.
3352</p>
3353
3354<h5>Semantics:</h5>
3355
3356<p>
3357The elements of the two input vectors are numbered from left to right across
3358both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3359the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3360gets. The element selector may be undef (meaning "don't care") and the second
3361operand may be undef if performing a shuffle from only one vector.
3362</p>
3363
3364<h5>Example:</h5>
3365
3366<pre>
3367 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3368 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3369 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3370 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3371 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3372 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3373 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3374 &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]3375</pre>
3376</div>
3377
3378
3379<!-- ======================================================================= -->
3380<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3381 <a name="aggregateops">Aggregate Operations</a>
3382</div>
3383
3384<div class="doc_text">
3385
3386<p>LLVM supports several instructions for working with aggregate values.
3387</p>
3388
3389</div>
3390
3391<!-- _______________________________________________________________________ -->
3392<div class="doc_subsubsection">
3393 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3394</div>
3395
3396<div class="doc_text">
3397
3398<h5>Syntax:</h5>
3399
3400<pre>
3401 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3402</pre>
3403
3404<h5>Overview:</h5>
3405
3406<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3407The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3408or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3409</p>
3410
3411
3412<h5>Arguments:</h5>
3413
3414<p>
3415The first operand of an '<tt>extractvalue</tt>' instruction is a
3416value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3417type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3418in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3419'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3420</p>
3421
3422<h5>Semantics:</h5>
3423
3424<p>
3425The result is the value at the position in the aggregate specified by
3426the index operands.
3427</p>
3428
3429<h5>Example:</h5>
3430
3431<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3432 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3433</pre>
3434</div>
3435
3436
3437<!-- _______________________________________________________________________ -->
3438<div class="doc_subsubsection">
3439 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3440</div>
3441
3442<div class="doc_text">
3443
3444<h5>Syntax:</h5>
3445
3446<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3447 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3448</pre>
3449
3450<h5>Overview:</h5>
3451
3452<p>
3453The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3454into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3455</p>
3456
3457
3458<h5>Arguments:</h5>
3459
3460<p>
3461The first operand of an '<tt>insertvalue</tt>' instruction is a
3462value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3463The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3464The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3465indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3466indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3467'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3468The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3469by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3470</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3471
3472<h5>Semantics:</h5>
3473
3474<p>
3475The result is an aggregate of the same type as <tt>val</tt>. Its
3476value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3477specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3478</p>
3479
3480<h5>Example:</h5>
3481
3482<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3483 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3484</pre>
3485</div>
3486
3487
3488<!-- ======================================================================= -->
3489<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3490 <a name="memoryops">Memory Access and Addressing Operations</a>
3491</div>
3492
3493<div class="doc_text">
3494
3495<p>A key design point of an SSA-based representation is how it
3496represents memory. In LLVM, no memory locations are in SSA form, which
3497makes things very simple. This section describes how to read, write,
3498allocate, and free memory in LLVM.</p>
3499
3500</div>
3501
3502<!-- _______________________________________________________________________ -->
3503<div class="doc_subsubsection">
3504 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3505</div>
3506
3507<div class="doc_text">
3508
3509<h5>Syntax:</h5>
3510
3511<pre>
3512 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3513</pre>
3514
3515<h5>Overview:</h5>
3516
3517<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3518heap and returns a pointer to it. The object is always allocated in the generic
3519address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3520
3521<h5>Arguments:</h5>
3522
3523<p>The '<tt>malloc</tt>' instruction allocates
3524<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3525bytes of memory from the operating system and returns a pointer of the
3526appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3527number of elements allocated, otherwise "NumElements" is defaulted to be one.
Duncan Sandsb38ce6f2009-06-20 13:26:06 +0000[diff] [blame]3528If a constant alignment is specified, the value result of the allocation is
3529guaranteed to be aligned to at least that boundary. If not specified, or if
3530zero, the target can choose to align the allocation on any convenient boundary
3531compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3532
3533<p>'<tt>type</tt>' must be a sized type.</p>
3534
3535<h5>Semantics:</h5>
3536
3537<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3538a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3539result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3540
3541<h5>Example:</h5>
3542
3543<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3544 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3545
3546 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3547 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3548 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3549 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3550 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3551</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3552
3553<p>Note that the code generator does not yet respect the
3554 alignment value.</p>
3555
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3556</div>
3557
3558<!-- _______________________________________________________________________ -->
3559<div class="doc_subsubsection">
3560 <a name="i_free">'<tt>free</tt>' Instruction</a>
3561</div>
3562
3563<div class="doc_text">
3564
3565<h5>Syntax:</h5>
3566
3567<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3568 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3569</pre>
3570
3571<h5>Overview:</h5>
3572
3573<p>The '<tt>free</tt>' instruction returns memory back to the unused
3574memory heap to be reallocated in the future.</p>
3575
3576<h5>Arguments:</h5>
3577
3578<p>'<tt>value</tt>' shall be a pointer value that points to a value
3579that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3580instruction.</p>
3581
3582<h5>Semantics:</h5>
3583
3584<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3585after this instruction executes. If the pointer is null, the operation
3586is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3587
3588<h5>Example:</h5>
3589
3590<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3591 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592 free [4 x i8]* %array
3593</pre>
3594</div>
3595
3596<!-- _______________________________________________________________________ -->
3597<div class="doc_subsubsection">
3598 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3599</div>
3600
3601<div class="doc_text">
3602
3603<h5>Syntax:</h5>
3604
3605<pre>
3606 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3607</pre>
3608
3609<h5>Overview:</h5>
3610
3611<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3612currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3613returns to its caller. The object is always allocated in the generic address
3614space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3615
3616<h5>Arguments:</h5>
3617
3618<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3619bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3620appropriate type to the program. If "NumElements" is specified, it is the
3621number of elements allocated, otherwise "NumElements" is defaulted to be one.
Duncan Sandsb38ce6f2009-06-20 13:26:06 +0000[diff] [blame]3622If a constant alignment is specified, the value result of the allocation is
3623guaranteed to be aligned to at least that boundary. If not specified, or if
3624zero, the target can choose to align the allocation on any convenient boundary
3625compatible with the type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626
3627<p>'<tt>type</tt>' may be any sized type.</p>
3628
3629<h5>Semantics:</h5>
3630
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3631<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3632there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3633memory is automatically released when the function returns. The '<tt>alloca</tt>'
3634instruction is commonly used to represent automatic variables that must
3635have an address available. When the function returns (either with the <tt><a
3636 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3637instructions), the memory is reclaimed. Allocating zero bytes
3638is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3639
3640<h5>Example:</h5>
3641
3642<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3643 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3644 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3645 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3646 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647</pre>
3648</div>
3649
3650<!-- _______________________________________________________________________ -->
3651<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3652Instruction</a> </div>
3653<div class="doc_text">
3654<h5>Syntax:</h5>
3655<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
3656<h5>Overview:</h5>
3657<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3658<h5>Arguments:</h5>
3659<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3660address from which to load. The pointer must point to a <a
3661 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3662marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3663the number or order of execution of this <tt>load</tt> with other
3664volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3665instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3666<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3667The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3668(that is, the alignment of the memory address). A value of 0 or an
3669omitted "align" argument means that the operation has the preferential
3670alignment for the target. It is the responsibility of the code emitter
3671to ensure that the alignment information is correct. Overestimating
3672the alignment results in an undefined behavior. Underestimating the
3673alignment may produce less efficient code. An alignment of 1 is always
3674safe.
3675</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3676<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3677<p>The location of memory pointed to is loaded. If the value being loaded
3678is of scalar type then the number of bytes read does not exceed the minimum
3679number of bytes needed to hold all bits of the type. For example, loading an
3680<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3681<tt>i20</tt> with a size that is not an integral number of bytes, the result
3682is undefined if the value was not originally written using a store of the
3683same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3684<h5>Examples:</h5>
3685<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3686 <a
3687 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3688 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3689</pre>
3690</div>
3691<!-- _______________________________________________________________________ -->
3692<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3693Instruction</a> </div>
3694<div class="doc_text">
3695<h5>Syntax:</h5>
3696<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3697 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3698</pre>
3699<h5>Overview:</h5>
3700<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3701<h5>Arguments:</h5>
3702<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3703to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3704operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3705of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3706operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3707optimizer is not allowed to modify the number or order of execution of
3708this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3709 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3710<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3711The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3712(that is, the alignment of the memory address). A value of 0 or an
3713omitted "align" argument means that the operation has the preferential
3714alignment for the target. It is the responsibility of the code emitter
3715to ensure that the alignment information is correct. Overestimating
3716the alignment results in an undefined behavior. Underestimating the
3717alignment may produce less efficient code. An alignment of 1 is always
3718safe.
3719</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3720<h5>Semantics:</h5>
3721<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3722at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3723If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3724written does not exceed the minimum number of bytes needed to hold all
3725bits of the type. For example, storing an <tt>i24</tt> writes at most
3726three bytes. When writing a value of a type like <tt>i20</tt> with a
3727size that is not an integral number of bytes, it is unspecified what
3728happens to the extra bits that do not belong to the type, but they will
3729typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3730<h5>Example:</h5>
3731<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3732 store i32 3, i32* %ptr <i>; yields {void}</i>
3733 %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]3734</pre>
3735</div>
3736
3737<!-- _______________________________________________________________________ -->
3738<div class="doc_subsubsection">
3739 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3740</div>
3741
3742<div class="doc_text">
3743<h5>Syntax:</h5>
3744<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3745 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746</pre>
3747
3748<h5>Overview:</h5>
3749
3750<p>
3751The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3752subelement of an aggregate data structure. It performs address calculation only
3753and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3754
3755<h5>Arguments:</h5>
3756
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3757<p>The first argument is always a pointer, and forms the basis of the
3758calculation. The remaining arguments are indices, that indicate which of the
3759elements of the aggregate object are indexed. The interpretation of each index
3760is dependent on the type being indexed into. The first index always indexes the
3761pointer value given as the first argument, the second index indexes a value of
3762the type pointed to (not necessarily the value directly pointed to, since the
3763first index can be non-zero), etc. The first type indexed into must be a pointer
3764value, subsequent types can be arrays, vectors and structs. Note that subsequent
3765types being indexed into can never be pointers, since that would require loading
3766the pointer before continuing calculation.</p>
3767
3768<p>The type of each index argument depends on the type it is indexing into.
3769When indexing into a (packed) structure, only <tt>i32</tt> integer
3770<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3771integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3772
3773<p>For example, let's consider a C code fragment and how it gets
3774compiled to LLVM:</p>
3775
3776<div class="doc_code">
3777<pre>
3778struct RT {
3779 char A;
3780 int B[10][20];
3781 char C;
3782};
3783struct ST {
3784 int X;
3785 double Y;
3786 struct RT Z;
3787};
3788
3789int *foo(struct ST *s) {
3790 return &amp;s[1].Z.B[5][13];
3791}
3792</pre>
3793</div>
3794
3795<p>The LLVM code generated by the GCC frontend is:</p>
3796
3797<div class="doc_code">
3798<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3799%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3800%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3801
3802define i32* %foo(%ST* %s) {
3803entry:
3804 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3805 ret i32* %reg
3806}
3807</pre>
3808</div>
3809
3810<h5>Semantics:</h5>
3811
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3812<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3813type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3814}</tt>' type, a structure. The second index indexes into the third element of
3815the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3816i8 }</tt>' type, another structure. The third index indexes into the second
3817element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3818array. The two dimensions of the array are subscripted into, yielding an
3819'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3820to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3821
3822<p>Note that it is perfectly legal to index partially through a
3823structure, returning a pointer to an inner element. Because of this,
3824the LLVM code for the given testcase is equivalent to:</p>
3825
3826<pre>
3827 define i32* %foo(%ST* %s) {
3828 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3829 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3830 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3831 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3832 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3833 ret i32* %t5
3834 }
3835</pre>
3836
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3837<p>Note that it is undefined to access an array out of bounds: array
3838and pointer indexes must always be within the defined bounds of the
3839array type when accessed with an instruction that dereferences the
3840pointer (e.g. a load or store instruction). The one exception for
3841this rule is zero length arrays. These arrays are defined to be
3842accessible as variable length arrays, which requires access beyond the
3843zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3844
3845<p>The getelementptr instruction is often confusing. For some more insight
3846into how it works, see <a href="GetElementPtr.html">the getelementptr
3847FAQ</a>.</p>
3848
3849<h5>Example:</h5>
3850
3851<pre>
3852 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3853 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3854 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3855 %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]3856 <i>; yields i8*:eptr</i>
3857 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3858 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3859 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3860</pre>
3861</div>
3862
3863<!-- ======================================================================= -->
3864<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3865</div>
3866<div class="doc_text">
3867<p>The instructions in this category are the conversion instructions (casting)
3868which all take a single operand and a type. They perform various bit conversions
3869on the operand.</p>
3870</div>
3871
3872<!-- _______________________________________________________________________ -->
3873<div class="doc_subsubsection">
3874 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3875</div>
3876<div class="doc_text">
3877
3878<h5>Syntax:</h5>
3879<pre>
3880 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3881</pre>
3882
3883<h5>Overview:</h5>
3884<p>
3885The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3886</p>
3887
3888<h5>Arguments:</h5>
3889<p>
3890The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3891be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3892and type of the result, which must be an <a href="#t_integer">integer</a>
3893type. The bit size of <tt>value</tt> must be larger than the bit size of
3894<tt>ty2</tt>. Equal sized types are not allowed.</p>
3895
3896<h5>Semantics:</h5>
3897<p>
3898The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3899and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3900larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3901It will always truncate bits.</p>
3902
3903<h5>Example:</h5>
3904<pre>
3905 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3906 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3907 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3908</pre>
3909</div>
3910
3911<!-- _______________________________________________________________________ -->
3912<div class="doc_subsubsection">
3913 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3914</div>
3915<div class="doc_text">
3916
3917<h5>Syntax:</h5>
3918<pre>
3919 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3920</pre>
3921
3922<h5>Overview:</h5>
3923<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3924<tt>ty2</tt>.</p>
3925
3926
3927<h5>Arguments:</h5>
3928<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3929<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3930also be of <a href="#t_integer">integer</a> type. The bit size of the
3931<tt>value</tt> must be smaller than the bit size of the destination type,
3932<tt>ty2</tt>.</p>
3933
3934<h5>Semantics:</h5>
3935<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3936bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3937
3938<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3939
3940<h5>Example:</h5>
3941<pre>
3942 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3943 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3944</pre>
3945</div>
3946
3947<!-- _______________________________________________________________________ -->
3948<div class="doc_subsubsection">
3949 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3950</div>
3951<div class="doc_text">
3952
3953<h5>Syntax:</h5>
3954<pre>
3955 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3956</pre>
3957
3958<h5>Overview:</h5>
3959<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3960
3961<h5>Arguments:</h5>
3962<p>
3963The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3964<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3965also be of <a href="#t_integer">integer</a> type. The bit size of the
3966<tt>value</tt> must be smaller than the bit size of the destination type,
3967<tt>ty2</tt>.</p>
3968
3969<h5>Semantics:</h5>
3970<p>
3971The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3972bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3973the type <tt>ty2</tt>.</p>
3974
3975<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3976
3977<h5>Example:</h5>
3978<pre>
3979 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3980 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3981</pre>
3982</div>
3983
3984<!-- _______________________________________________________________________ -->
3985<div class="doc_subsubsection">
3986 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3987</div>
3988
3989<div class="doc_text">
3990
3991<h5>Syntax:</h5>
3992
3993<pre>
3994 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3995</pre>
3996
3997<h5>Overview:</h5>
3998<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3999<tt>ty2</tt>.</p>
4000
4001
4002<h5>Arguments:</h5>
4003<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
4004 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
4005cast it to. The size of <tt>value</tt> must be larger than the size of
4006<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4007<i>no-op cast</i>.</p>
4008
4009<h5>Semantics:</h5>
4010<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4011<a href="#t_floating">floating point</a> type to a smaller
4012<a href="#t_floating">floating point</a> type. If the value cannot fit within
4013the destination type, <tt>ty2</tt>, then the results are undefined.</p>
4014
4015<h5>Example:</h5>
4016<pre>
4017 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4018 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4019</pre>
4020</div>
4021
4022<!-- _______________________________________________________________________ -->
4023<div class="doc_subsubsection">
4024 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4025</div>
4026<div class="doc_text">
4027
4028<h5>Syntax:</h5>
4029<pre>
4030 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4031</pre>
4032
4033<h5>Overview:</h5>
4034<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
4035floating point value.</p>
4036
4037<h5>Arguments:</h5>
4038<p>The '<tt>fpext</tt>' instruction takes a
4039<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
4040and a <a href="#t_floating">floating point</a> type to cast it to. The source
4041type must be smaller than the destination type.</p>
4042
4043<h5>Semantics:</h5>
4044<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
4045<a href="#t_floating">floating point</a> type to a larger
4046<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4047used to make a <i>no-op cast</i> because it always changes bits. Use
4048<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
4049
4050<h5>Example:</h5>
4051<pre>
4052 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4053 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4054</pre>
4055</div>
4056
4057<!-- _______________________________________________________________________ -->
4058<div class="doc_subsubsection">
4059 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4060</div>
4061<div class="doc_text">
4062
4063<h5>Syntax:</h5>
4064<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4065 &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]4066</pre>
4067
4068<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4069<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070unsigned integer equivalent of type <tt>ty2</tt>.
4071</p>
4072
4073<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4074<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4075scalar or vector <a href="#t_floating">floating point</a> value, and a type
4076to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4077type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4078vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4079
4080<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4081<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4082<a href="#t_floating">floating point</a> operand into the nearest (rounding
4083towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
4084the results are undefined.</p>
4085
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4086<h5>Example:</h5>
4087<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4088 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4089 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4090 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4091</pre>
4092</div>
4093
4094<!-- _______________________________________________________________________ -->
4095<div class="doc_subsubsection">
4096 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4097</div>
4098<div class="doc_text">
4099
4100<h5>Syntax:</h5>
4101<pre>
4102 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4103</pre>
4104
4105<h5>Overview:</h5>
4106<p>The '<tt>fptosi</tt>' instruction converts
4107<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
4108</p>
4109
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4110<h5>Arguments:</h5>
4111<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4112scalar or vector <a href="#t_floating">floating point</a> value, and a type
4113to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4114type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4115vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4116
4117<h5>Semantics:</h5>
4118<p>The '<tt>fptosi</tt>' instruction converts its
4119<a href="#t_floating">floating point</a> operand into the nearest (rounding
4120towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4121the results are undefined.</p>
4122
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4123<h5>Example:</h5>
4124<pre>
4125 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4126 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4127 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4128</pre>
4129</div>
4130
4131<!-- _______________________________________________________________________ -->
4132<div class="doc_subsubsection">
4133 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4134</div>
4135<div class="doc_text">
4136
4137<h5>Syntax:</h5>
4138<pre>
4139 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4140</pre>
4141
4142<h5>Overview:</h5>
4143<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4144integer and converts that value to the <tt>ty2</tt> type.</p>
4145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4146<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4147<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4148scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4149to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4150type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4151floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4152
4153<h5>Semantics:</h5>
4154<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4155integer quantity and converts it to the corresponding floating point value. If
4156the value cannot fit in the floating point value, the results are undefined.</p>
4157
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4158<h5>Example:</h5>
4159<pre>
4160 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4161 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4162</pre>
4163</div>
4164
4165<!-- _______________________________________________________________________ -->
4166<div class="doc_subsubsection">
4167 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4168</div>
4169<div class="doc_text">
4170
4171<h5>Syntax:</h5>
4172<pre>
4173 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4174</pre>
4175
4176<h5>Overview:</h5>
4177<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4178integer and converts that value to the <tt>ty2</tt> type.</p>
4179
4180<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4181<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4182scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4183to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4184type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4185floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4186
4187<h5>Semantics:</h5>
4188<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4189integer quantity and converts it to the corresponding floating point value. If
4190the value cannot fit in the floating point value, the results are undefined.</p>
4191
4192<h5>Example:</h5>
4193<pre>
4194 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4195 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4196</pre>
4197</div>
4198
4199<!-- _______________________________________________________________________ -->
4200<div class="doc_subsubsection">
4201 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4202</div>
4203<div class="doc_text">
4204
4205<h5>Syntax:</h5>
4206<pre>
4207 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4208</pre>
4209
4210<h5>Overview:</h5>
4211<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4212the integer type <tt>ty2</tt>.</p>
4213
4214<h5>Arguments:</h5>
4215<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4216must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4217<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]4218
4219<h5>Semantics:</h5>
4220<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4221<tt>ty2</tt> by interpreting the pointer value as an integer and either
4222truncating or zero extending that value to the size of the integer type. If
4223<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4224<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4225are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4226change.</p>
4227
4228<h5>Example:</h5>
4229<pre>
4230 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4231 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4232</pre>
4233</div>
4234
4235<!-- _______________________________________________________________________ -->
4236<div class="doc_subsubsection">
4237 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4238</div>
4239<div class="doc_text">
4240
4241<h5>Syntax:</h5>
4242<pre>
4243 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4244</pre>
4245
4246<h5>Overview:</h5>
4247<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4248a pointer type, <tt>ty2</tt>.</p>
4249
4250<h5>Arguments:</h5>
4251<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4252value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4253<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4254
4255<h5>Semantics:</h5>
4256<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4257<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4258the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4259size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4260the size of a pointer then a zero extension is done. If they are the same size,
4261nothing is done (<i>no-op cast</i>).</p>
4262
4263<h5>Example:</h5>
4264<pre>
4265 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4266 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4267 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4268</pre>
4269</div>
4270
4271<!-- _______________________________________________________________________ -->
4272<div class="doc_subsubsection">
4273 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4274</div>
4275<div class="doc_text">
4276
4277<h5>Syntax:</h5>
4278<pre>
4279 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4280</pre>
4281
4282<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4284<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4285<tt>ty2</tt> without changing any bits.</p>
4286
4287<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4289<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4290a non-aggregate first class value, and a type to cast it to, which must also be
4291a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4292<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4293and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4294type is a pointer, the destination type must also be a pointer. This
4295instruction supports bitwise conversion of vectors to integers and to vectors
4296of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4297
4298<h5>Semantics:</h5>
4299<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4300<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4301this conversion. The conversion is done as if the <tt>value</tt> had been
4302stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4303converted to other pointer types with this instruction. To convert pointers to
4304other types, use the <a href="#i_inttoptr">inttoptr</a> or
4305<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4306
4307<h5>Example:</h5>
4308<pre>
4309 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4310 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4311 %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]4312</pre>
4313</div>
4314
4315<!-- ======================================================================= -->
4316<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4317<div class="doc_text">
4318<p>The instructions in this category are the "miscellaneous"
4319instructions, which defy better classification.</p>
4320</div>
4321
4322<!-- _______________________________________________________________________ -->
4323<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4324</div>
4325<div class="doc_text">
4326<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4327<pre> &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]4328</pre>
4329<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4330<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4331a vector of boolean values based on comparison
4332of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333<h5>Arguments:</h5>
4334<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4335the condition code indicating the kind of comparison to perform. It is not
4336a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4337</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4338<ol>
4339 <li><tt>eq</tt>: equal</li>
4340 <li><tt>ne</tt>: not equal </li>
4341 <li><tt>ugt</tt>: unsigned greater than</li>
4342 <li><tt>uge</tt>: unsigned greater or equal</li>
4343 <li><tt>ult</tt>: unsigned less than</li>
4344 <li><tt>ule</tt>: unsigned less or equal</li>
4345 <li><tt>sgt</tt>: signed greater than</li>
4346 <li><tt>sge</tt>: signed greater or equal</li>
4347 <li><tt>slt</tt>: signed less than</li>
4348 <li><tt>sle</tt>: signed less or equal</li>
4349</ol>
4350<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4351<a href="#t_pointer">pointer</a>
4352or integer <a href="#t_vector">vector</a> typed.
4353They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4355<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4356the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4357yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4358</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359<ol>
4360 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4361 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4362 </li>
4363 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4364 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4365 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4366 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4367 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4368 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4370 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4371 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4372 <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]4373 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4374 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4376 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4377 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4378 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4379 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4380 <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]4381</ol>
4382<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4383values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4384<p>If the operands are integer vectors, then they are compared
4385element by element. The result is an <tt>i1</tt> vector with
4386the same number of elements as the values being compared.
4387Otherwise, the result is an <tt>i1</tt>.
4388</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4389
4390<h5>Example:</h5>
4391<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4392 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4393 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4394 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4395 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4396 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4397</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4398
4399<p>Note that the code generator does not yet support vector types with
4400 the <tt>icmp</tt> instruction.</p>
4401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4402</div>
4403
4404<!-- _______________________________________________________________________ -->
4405<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4406</div>
4407<div class="doc_text">
4408<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4409<pre> &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]4410</pre>
4411<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4412<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4413or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4414of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4415<p>
4416If the operands are floating point scalars, then the result
4417type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4418</p>
4419<p>If the operands are floating point vectors, then the result type
4420is a vector of boolean with the same number of elements as the
4421operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4422<h5>Arguments:</h5>
4423<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4424the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4425a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426<ol>
4427 <li><tt>false</tt>: no comparison, always returns false</li>
4428 <li><tt>oeq</tt>: ordered and equal</li>
4429 <li><tt>ogt</tt>: ordered and greater than </li>
4430 <li><tt>oge</tt>: ordered and greater than or equal</li>
4431 <li><tt>olt</tt>: ordered and less than </li>
4432 <li><tt>ole</tt>: ordered and less than or equal</li>
4433 <li><tt>one</tt>: ordered and not equal</li>
4434 <li><tt>ord</tt>: ordered (no nans)</li>
4435 <li><tt>ueq</tt>: unordered or equal</li>
4436 <li><tt>ugt</tt>: unordered or greater than </li>
4437 <li><tt>uge</tt>: unordered or greater than or equal</li>
4438 <li><tt>ult</tt>: unordered or less than </li>
4439 <li><tt>ule</tt>: unordered or less than or equal</li>
4440 <li><tt>une</tt>: unordered or not equal</li>
4441 <li><tt>uno</tt>: unordered (either nans)</li>
4442 <li><tt>true</tt>: no comparison, always returns true</li>
4443</ol>
4444<p><i>Ordered</i> means that neither operand is a QNAN while
4445<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4446<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4447either a <a href="#t_floating">floating point</a> type
4448or a <a href="#t_vector">vector</a> of floating point type.
4449They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4450<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4451<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4452according to the condition code given as <tt>cond</tt>.
4453If the operands are vectors, then the vectors are compared
4454element by element.
4455Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4456always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4457<ol>
4458 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4459 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4460 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4461 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4462 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4463 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4464 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4465 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4466 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4467 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4468 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4470 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4471 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4472 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4473 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4475 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4477 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4478 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4479 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4481 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4483 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4485 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4486</ol>
4487
4488<h5>Example:</h5>
4489<pre> &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]4490 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4491 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4492 &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]4493</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4494
4495<p>Note that the code generator does not yet support vector types with
4496 the <tt>fcmp</tt> instruction.</p>
4497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4498</div>
4499
4500<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4501<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4502 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4503</div>
4504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4505<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4507<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4509<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4510<h5>Overview:</h5>
4511<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4512the SSA graph representing the function.</p>
4513<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4515<p>The type of the incoming values is specified with the first type
4516field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4517as arguments, with one pair for each predecessor basic block of the
4518current block. Only values of <a href="#t_firstclass">first class</a>
4519type may be used as the value arguments to the PHI node. Only labels
4520may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522<p>There must be no non-phi instructions between the start of a basic
4523block and the PHI instructions: i.e. PHI instructions must be first in
4524a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4525
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4526<p>For the purposes of the SSA form, the use of each incoming value is
4527deemed to occur on the edge from the corresponding predecessor block
4528to the current block (but after any definition of an '<tt>invoke</tt>'
4529instruction's return value on the same edge).</p>
4530
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4531<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4533<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4534specified by the pair corresponding to the predecessor basic block that executed
4535just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4537<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4538<pre>
4539Loop: ; Infinite loop that counts from 0 on up...
4540 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4541 %nextindvar = add i32 %indvar, 1
4542 br label %Loop
4543</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4544</div>
4545
4546<!-- _______________________________________________________________________ -->
4547<div class="doc_subsubsection">
4548 <a name="i_select">'<tt>select</tt>' Instruction</a>
4549</div>
4550
4551<div class="doc_text">
4552
4553<h5>Syntax:</h5>
4554
4555<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4556 &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>
4557
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4558 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4559</pre>
4560
4561<h5>Overview:</h5>
4562
4563<p>
4564The '<tt>select</tt>' instruction is used to choose one value based on a
4565condition, without branching.
4566</p>
4567
4568
4569<h5>Arguments:</h5>
4570
4571<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4572The '<tt>select</tt>' instruction requires an 'i1' value or
4573a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4574condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4575type. If the val1/val2 are vectors and
4576the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4577individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4578</p>
4579
4580<h5>Semantics:</h5>
4581
4582<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4583If the condition is an i1 and it evaluates to 1, the instruction returns the first
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584value argument; otherwise, it returns the second value argument.
4585</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4586<p>
4587If the condition is a vector of i1, then the value arguments must
4588be vectors of the same size, and the selection is done element
4589by element.
4590</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4591
4592<h5>Example:</h5>
4593
4594<pre>
4595 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4596</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4597
4598<p>Note that the code generator does not yet support conditions
4599 with vector type.</p>
4600
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4601</div>
4602
4603
4604<!-- _______________________________________________________________________ -->
4605<div class="doc_subsubsection">
4606 <a name="i_call">'<tt>call</tt>' Instruction</a>
4607</div>
4608
4609<div class="doc_text">
4610
4611<h5>Syntax:</h5>
4612<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4613 &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]4614</pre>
4615
4616<h5>Overview:</h5>
4617
4618<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4619
4620<h5>Arguments:</h5>
4621
4622<p>This instruction requires several arguments:</p>
4623
4624<ol>
4625 <li>
4626 <p>The optional "tail" marker indicates whether the callee function accesses
4627 any allocas or varargs in the caller. If the "tail" marker is present, the
4628 function call is eligible for tail call optimization. Note that calls may
4629 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4630 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4631 </li>
4632 <li>
4633 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4634 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4635 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4636 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4637
4638 <li>
4639 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4640 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4641 and '<tt>inreg</tt>' attributes are valid here.</p>
4642 </li>
4643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4644 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4645 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4646 the type of the return value. Functions that return no value are marked
4647 <tt><a href="#t_void">void</a></tt>.</p>
4648 </li>
4649 <li>
4650 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4651 value being invoked. The argument types must match the types implied by
4652 this signature. This type can be omitted if the function is not varargs
4653 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4654 </li>
4655 <li>
4656 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4657 be invoked. In most cases, this is a direct function invocation, but
4658 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4659 to function value.</p>
4660 </li>
4661 <li>
4662 <p>'<tt>function args</tt>': argument list whose types match the
4663 function signature argument types. All arguments must be of
4664 <a href="#t_firstclass">first class</a> type. If the function signature
4665 indicates the function accepts a variable number of arguments, the extra
4666 arguments can be specified.</p>
4667 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4668 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4669 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4670 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4671 '<tt>readnone</tt>' attributes are valid here.</p>
4672 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673</ol>
4674
4675<h5>Semantics:</h5>
4676
4677<p>The '<tt>call</tt>' instruction is used to cause control flow to
4678transfer to a specified function, with its incoming arguments bound to
4679the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4680instruction in the called function, control flow continues with the
4681instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4682function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4683
4684<h5>Example:</h5>
4685
4686<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4687 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4688 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4689 %X = tail call i32 @foo() <i>; yields i32</i>
4690 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4691 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4692
4693 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4694 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4695 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4696 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4697 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4698 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4699</pre>
4700
4701</div>
4702
4703<!-- _______________________________________________________________________ -->
4704<div class="doc_subsubsection">
4705 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4706</div>
4707
4708<div class="doc_text">
4709
4710<h5>Syntax:</h5>
4711
4712<pre>
4713 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4714</pre>
4715
4716<h5>Overview:</h5>
4717
4718<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4719the "variable argument" area of a function call. It is used to implement the
4720<tt>va_arg</tt> macro in C.</p>
4721
4722<h5>Arguments:</h5>
4723
4724<p>This instruction takes a <tt>va_list*</tt> value and the type of
4725the argument. It returns a value of the specified argument type and
4726increments the <tt>va_list</tt> to point to the next argument. The
4727actual type of <tt>va_list</tt> is target specific.</p>
4728
4729<h5>Semantics:</h5>
4730
4731<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4732type from the specified <tt>va_list</tt> and causes the
4733<tt>va_list</tt> to point to the next argument. For more information,
4734see the variable argument handling <a href="#int_varargs">Intrinsic
4735Functions</a>.</p>
4736
4737<p>It is legal for this instruction to be called in a function which does not
4738take a variable number of arguments, for example, the <tt>vfprintf</tt>
4739function.</p>
4740
4741<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4742href="#intrinsics">intrinsic function</a> because it takes a type as an
4743argument.</p>
4744
4745<h5>Example:</h5>
4746
4747<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4748
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4749<p>Note that the code generator does not yet fully support va_arg
4750 on many targets. Also, it does not currently support va_arg with
4751 aggregate types on any target.</p>
4752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753</div>
4754
4755<!-- *********************************************************************** -->
4756<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4757<!-- *********************************************************************** -->
4758
4759<div class="doc_text">
4760
4761<p>LLVM supports the notion of an "intrinsic function". These functions have
4762well known names and semantics and are required to follow certain restrictions.
4763Overall, these intrinsics represent an extension mechanism for the LLVM
4764language that does not require changing all of the transformations in LLVM when
4765adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4766
4767<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4768prefix is reserved in LLVM for intrinsic names; thus, function names may not
4769begin with this prefix. Intrinsic functions must always be external functions:
4770you cannot define the body of intrinsic functions. Intrinsic functions may
4771only be used in call or invoke instructions: it is illegal to take the address
4772of an intrinsic function. Additionally, because intrinsic functions are part
4773of the LLVM language, it is required if any are added that they be documented
4774here.</p>
4775
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4776<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4777a family of functions that perform the same operation but on different data
4778types. Because LLVM can represent over 8 million different integer types,
4779overloading is used commonly to allow an intrinsic function to operate on any
4780integer type. One or more of the argument types or the result type can be
4781overloaded to accept any integer type. Argument types may also be defined as
4782exactly matching a previous argument's type or the result type. This allows an
4783intrinsic function which accepts multiple arguments, but needs all of them to
4784be of the same type, to only be overloaded with respect to a single argument or
4785the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4786
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4787<p>Overloaded intrinsics will have the names of its overloaded argument types
4788encoded into its function name, each preceded by a period. Only those types
4789which are overloaded result in a name suffix. Arguments whose type is matched
4790against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4791take an integer of any width and returns an integer of exactly the same integer
4792width. This leads to a family of functions such as
4793<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4794Only one type, the return type, is overloaded, and only one type suffix is
4795required. Because the argument's type is matched against the return type, it
4796does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4797
4798<p>To learn how to add an intrinsic function, please see the
4799<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4800</p>
4801
4802</div>
4803
4804<!-- ======================================================================= -->
4805<div class="doc_subsection">
4806 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4807</div>
4808
4809<div class="doc_text">
4810
4811<p>Variable argument support is defined in LLVM with the <a
4812 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4813intrinsic functions. These functions are related to the similarly
4814named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4815
4816<p>All of these functions operate on arguments that use a
4817target-specific value type "<tt>va_list</tt>". The LLVM assembly
4818language reference manual does not define what this type is, so all
4819transformations should be prepared to handle these functions regardless of
4820the type used.</p>
4821
4822<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4823instruction and the variable argument handling intrinsic functions are
4824used.</p>
4825
4826<div class="doc_code">
4827<pre>
4828define i32 @test(i32 %X, ...) {
4829 ; Initialize variable argument processing
4830 %ap = alloca i8*
4831 %ap2 = bitcast i8** %ap to i8*
4832 call void @llvm.va_start(i8* %ap2)
4833
4834 ; Read a single integer argument
4835 %tmp = va_arg i8** %ap, i32
4836
4837 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4838 %aq = alloca i8*
4839 %aq2 = bitcast i8** %aq to i8*
4840 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4841 call void @llvm.va_end(i8* %aq2)
4842
4843 ; Stop processing of arguments.
4844 call void @llvm.va_end(i8* %ap2)
4845 ret i32 %tmp
4846}
4847
4848declare void @llvm.va_start(i8*)
4849declare void @llvm.va_copy(i8*, i8*)
4850declare void @llvm.va_end(i8*)
4851</pre>
4852</div>
4853
4854</div>
4855
4856<!-- _______________________________________________________________________ -->
4857<div class="doc_subsubsection">
4858 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4859</div>
4860
4861
4862<div class="doc_text">
4863<h5>Syntax:</h5>
4864<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4865<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4866<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4867<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4868href="#i_va_arg">va_arg</a></tt>.</p>
4869
4870<h5>Arguments:</h5>
4871
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4872<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]4873
4874<h5>Semantics:</h5>
4875
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4876<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4877macro available in C. In a target-dependent way, it initializes the
4878<tt>va_list</tt> element to which the argument points, so that the next call to
4879<tt>va_arg</tt> will produce the first variable argument passed to the function.
4880Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4881last argument of the function as the compiler can figure that out.</p>
4882
4883</div>
4884
4885<!-- _______________________________________________________________________ -->
4886<div class="doc_subsubsection">
4887 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4888</div>
4889
4890<div class="doc_text">
4891<h5>Syntax:</h5>
4892<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4893<h5>Overview:</h5>
4894
4895<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4896which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4897or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4898
4899<h5>Arguments:</h5>
4900
4901<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4902
4903<h5>Semantics:</h5>
4904
4905<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4906macro available in C. In a target-dependent way, it destroys the
4907<tt>va_list</tt> element to which the argument points. Calls to <a
4908href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4909<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4910<tt>llvm.va_end</tt>.</p>
4911
4912</div>
4913
4914<!-- _______________________________________________________________________ -->
4915<div class="doc_subsubsection">
4916 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4917</div>
4918
4919<div class="doc_text">
4920
4921<h5>Syntax:</h5>
4922
4923<pre>
4924 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4925</pre>
4926
4927<h5>Overview:</h5>
4928
4929<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4930from the source argument list to the destination argument list.</p>
4931
4932<h5>Arguments:</h5>
4933
4934<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4935The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4936
4937
4938<h5>Semantics:</h5>
4939
4940<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4941macro available in C. In a target-dependent way, it copies the source
4942<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4943intrinsic is necessary because the <tt><a href="#int_va_start">
4944llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4945example, memory allocation.</p>
4946
4947</div>
4948
4949<!-- ======================================================================= -->
4950<div class="doc_subsection">
4951 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4952</div>
4953
4954<div class="doc_text">
4955
4956<p>
4957LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4958Collection</a> (GC) requires the implementation and generation of these
4959intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4960These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4961stack</a>, as well as garbage collector implementations that require <a
4962href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4963Front-ends for type-safe garbage collected languages should generate these
4964intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4965href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4966</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4967
4968<p>The garbage collection intrinsics only operate on objects in the generic
4969 address space (address space zero).</p>
4970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4971</div>
4972
4973<!-- _______________________________________________________________________ -->
4974<div class="doc_subsubsection">
4975 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4976</div>
4977
4978<div class="doc_text">
4979
4980<h5>Syntax:</h5>
4981
4982<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4983 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4984</pre>
4985
4986<h5>Overview:</h5>
4987
4988<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4989the code generator, and allows some metadata to be associated with it.</p>
4990
4991<h5>Arguments:</h5>
4992
4993<p>The first argument specifies the address of a stack object that contains the
4994root pointer. The second pointer (which must be either a constant or a global
4995value address) contains the meta-data to be associated with the root.</p>
4996
4997<h5>Semantics:</h5>
4998
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4999<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5000location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5001the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5002intrinsic may only be used in a function which <a href="#gc">specifies a GC
5003algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5004
5005</div>
5006
5007
5008<!-- _______________________________________________________________________ -->
5009<div class="doc_subsubsection">
5010 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5011</div>
5012
5013<div class="doc_text">
5014
5015<h5>Syntax:</h5>
5016
5017<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5018 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5019</pre>
5020
5021<h5>Overview:</h5>
5022
5023<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
5024locations, allowing garbage collector implementations that require read
5025barriers.</p>
5026
5027<h5>Arguments:</h5>
5028
5029<p>The second argument is the address to read from, which should be an address
5030allocated from the garbage collector. The first object is a pointer to the
5031start of the referenced object, if needed by the language runtime (otherwise
5032null).</p>
5033
5034<h5>Semantics:</h5>
5035
5036<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5037instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5038garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5039may only be used in a function which <a href="#gc">specifies a GC
5040algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5041
5042</div>
5043
5044
5045<!-- _______________________________________________________________________ -->
5046<div class="doc_subsubsection">
5047 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5048</div>
5049
5050<div class="doc_text">
5051
5052<h5>Syntax:</h5>
5053
5054<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5055 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5056</pre>
5057
5058<h5>Overview:</h5>
5059
5060<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5061locations, allowing garbage collector implementations that require write
5062barriers (such as generational or reference counting collectors).</p>
5063
5064<h5>Arguments:</h5>
5065
5066<p>The first argument is the reference to store, the second is the start of the
5067object to store it to, and the third is the address of the field of Obj to
5068store to. If the runtime does not require a pointer to the object, Obj may be
5069null.</p>
5070
5071<h5>Semantics:</h5>
5072
5073<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5074instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5075garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5076may only be used in a function which <a href="#gc">specifies a GC
5077algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078
5079</div>
5080
5081
5082
5083<!-- ======================================================================= -->
5084<div class="doc_subsection">
5085 <a name="int_codegen">Code Generator Intrinsics</a>
5086</div>
5087
5088<div class="doc_text">
5089<p>
5090These intrinsics are provided by LLVM to expose special features that may only
5091be implemented with code generator support.
5092</p>
5093
5094</div>
5095
5096<!-- _______________________________________________________________________ -->
5097<div class="doc_subsubsection">
5098 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5099</div>
5100
5101<div class="doc_text">
5102
5103<h5>Syntax:</h5>
5104<pre>
5105 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5106</pre>
5107
5108<h5>Overview:</h5>
5109
5110<p>
5111The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5112target-specific value indicating the return address of the current function
5113or one of its callers.
5114</p>
5115
5116<h5>Arguments:</h5>
5117
5118<p>
5119The argument to this intrinsic indicates which function to return the address
5120for. Zero indicates the calling function, one indicates its caller, etc. The
5121argument is <b>required</b> to be a constant integer value.
5122</p>
5123
5124<h5>Semantics:</h5>
5125
5126<p>
5127The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5128the return address of the specified call frame, or zero if it cannot be
5129identified. The value returned by this intrinsic is likely to be incorrect or 0
5130for arguments other than zero, so it should only be used for debugging purposes.
5131</p>
5132
5133<p>
5134Note that calling this intrinsic does not prevent function inlining or other
5135aggressive transformations, so the value returned may not be that of the obvious
5136source-language caller.
5137</p>
5138</div>
5139
5140
5141<!-- _______________________________________________________________________ -->
5142<div class="doc_subsubsection">
5143 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5144</div>
5145
5146<div class="doc_text">
5147
5148<h5>Syntax:</h5>
5149<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5150 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5151</pre>
5152
5153<h5>Overview:</h5>
5154
5155<p>
5156The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5157target-specific frame pointer value for the specified stack frame.
5158</p>
5159
5160<h5>Arguments:</h5>
5161
5162<p>
5163The argument to this intrinsic indicates which function to return the frame
5164pointer for. Zero indicates the calling function, one indicates its caller,
5165etc. The argument is <b>required</b> to be a constant integer value.
5166</p>
5167
5168<h5>Semantics:</h5>
5169
5170<p>
5171The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5172the frame address of the specified call frame, or zero if it cannot be
5173identified. The value returned by this intrinsic is likely to be incorrect or 0
5174for arguments other than zero, so it should only be used for debugging purposes.
5175</p>
5176
5177<p>
5178Note that calling this intrinsic does not prevent function inlining or other
5179aggressive transformations, so the value returned may not be that of the obvious
5180source-language caller.
5181</p>
5182</div>
5183
5184<!-- _______________________________________________________________________ -->
5185<div class="doc_subsubsection">
5186 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5187</div>
5188
5189<div class="doc_text">
5190
5191<h5>Syntax:</h5>
5192<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5193 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5194</pre>
5195
5196<h5>Overview:</h5>
5197
5198<p>
5199The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5200the function stack, for use with <a href="#int_stackrestore">
5201<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5202features like scoped automatic variable sized arrays in C99.
5203</p>
5204
5205<h5>Semantics:</h5>
5206
5207<p>
5208This intrinsic returns a opaque pointer value that can be passed to <a
5209href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5210<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5211<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5212state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5213practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5214that were allocated after the <tt>llvm.stacksave</tt> was executed.
5215</p>
5216
5217</div>
5218
5219<!-- _______________________________________________________________________ -->
5220<div class="doc_subsubsection">
5221 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5222</div>
5223
5224<div class="doc_text">
5225
5226<h5>Syntax:</h5>
5227<pre>
5228 declare void @llvm.stackrestore(i8 * %ptr)
5229</pre>
5230
5231<h5>Overview:</h5>
5232
5233<p>
5234The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5235the function stack to the state it was in when the corresponding <a
5236href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5237useful for implementing language features like scoped automatic variable sized
5238arrays in C99.
5239</p>
5240
5241<h5>Semantics:</h5>
5242
5243<p>
5244See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5245</p>
5246
5247</div>
5248
5249
5250<!-- _______________________________________________________________________ -->
5251<div class="doc_subsubsection">
5252 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5253</div>
5254
5255<div class="doc_text">
5256
5257<h5>Syntax:</h5>
5258<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5259 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]5260</pre>
5261
5262<h5>Overview:</h5>
5263
5264
5265<p>
5266The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5267a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5268no
5269effect on the behavior of the program but can change its performance
5270characteristics.
5271</p>
5272
5273<h5>Arguments:</h5>
5274
5275<p>
5276<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5277determining if the fetch should be for a read (0) or write (1), and
5278<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5279locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5280<tt>locality</tt> arguments must be constant integers.
5281</p>
5282
5283<h5>Semantics:</h5>
5284
5285<p>
5286This intrinsic does not modify the behavior of the program. In particular,
5287prefetches cannot trap and do not produce a value. On targets that support this
5288intrinsic, the prefetch can provide hints to the processor cache for better
5289performance.
5290</p>
5291
5292</div>
5293
5294<!-- _______________________________________________________________________ -->
5295<div class="doc_subsubsection">
5296 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5297</div>
5298
5299<div class="doc_text">
5300
5301<h5>Syntax:</h5>
5302<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5303 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5304</pre>
5305
5306<h5>Overview:</h5>
5307
5308
5309<p>
5310The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5311(PC) in a region of
5312code to simulators and other tools. The method is target specific, but it is
5313expected that the marker will use exported symbols to transmit the PC of the
5314marker.
5315The marker makes no guarantees that it will remain with any specific instruction
5316after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5317optimizations. The intended use is to be inserted after optimizations to allow
5318correlations of simulation runs.
5319</p>
5320
5321<h5>Arguments:</h5>
5322
5323<p>
5324<tt>id</tt> is a numerical id identifying the marker.
5325</p>
5326
5327<h5>Semantics:</h5>
5328
5329<p>
5330This intrinsic does not modify the behavior of the program. Backends that do not
5331support this intrinisic may ignore it.
5332</p>
5333
5334</div>
5335
5336<!-- _______________________________________________________________________ -->
5337<div class="doc_subsubsection">
5338 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5339</div>
5340
5341<div class="doc_text">
5342
5343<h5>Syntax:</h5>
5344<pre>
5345 declare i64 @llvm.readcyclecounter( )
5346</pre>
5347
5348<h5>Overview:</h5>
5349
5350
5351<p>
5352The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5353counter register (or similar low latency, high accuracy clocks) on those targets
5354that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5355As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5356should only be used for small timings.
5357</p>
5358
5359<h5>Semantics:</h5>
5360
5361<p>
5362When directly supported, reading the cycle counter should not modify any memory.
5363Implementations are allowed to either return a application specific value or a
5364system wide value. On backends without support, this is lowered to a constant 0.
5365</p>
5366
5367</div>
5368
5369<!-- ======================================================================= -->
5370<div class="doc_subsection">
5371 <a name="int_libc">Standard C Library Intrinsics</a>
5372</div>
5373
5374<div class="doc_text">
5375<p>
5376LLVM provides intrinsics for a few important standard C library functions.
5377These intrinsics allow source-language front-ends to pass information about the
5378alignment of the pointer arguments to the code generator, providing opportunity
5379for more efficient code generation.
5380</p>
5381
5382</div>
5383
5384<!-- _______________________________________________________________________ -->
5385<div class="doc_subsubsection">
5386 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5387</div>
5388
5389<div class="doc_text">
5390
5391<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5392<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5393width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5394<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5395 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5396 i8 &lt;len&gt;, i32 &lt;align&gt;)
5397 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5398 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5400 i32 &lt;len&gt;, i32 &lt;align&gt;)
5401 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5402 i64 &lt;len&gt;, i32 &lt;align&gt;)
5403</pre>
5404
5405<h5>Overview:</h5>
5406
5407<p>
5408The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5409location to the destination location.
5410</p>
5411
5412<p>
5413Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5414intrinsics do not return a value, and takes an extra alignment argument.
5415</p>
5416
5417<h5>Arguments:</h5>
5418
5419<p>
5420The first argument is a pointer to the destination, the second is a pointer to
5421the source. The third argument is an integer argument
5422specifying the number of bytes to copy, and the fourth argument is the alignment
5423of the source and destination locations.
5424</p>
5425
5426<p>
5427If the call to this intrinisic has an alignment value that is not 0 or 1, then
5428the caller guarantees that both the source and destination pointers are aligned
5429to that boundary.
5430</p>
5431
5432<h5>Semantics:</h5>
5433
5434<p>
5435The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5436location to the destination location, which are not allowed to overlap. It
5437copies "len" bytes of memory over. If the argument is known to be aligned to
5438some boundary, this can be specified as the fourth argument, otherwise it should
5439be set to 0 or 1.
5440</p>
5441</div>
5442
5443
5444<!-- _______________________________________________________________________ -->
5445<div class="doc_subsubsection">
5446 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5447</div>
5448
5449<div class="doc_text">
5450
5451<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5452<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5453width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5454<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5455 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5456 i8 &lt;len&gt;, i32 &lt;align&gt;)
5457 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5458 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5459 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5460 i32 &lt;len&gt;, i32 &lt;align&gt;)
5461 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5462 i64 &lt;len&gt;, i32 &lt;align&gt;)
5463</pre>
5464
5465<h5>Overview:</h5>
5466
5467<p>
5468The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5469location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5470'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5471</p>
5472
5473<p>
5474Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5475intrinsics do not return a value, and takes an extra alignment argument.
5476</p>
5477
5478<h5>Arguments:</h5>
5479
5480<p>
5481The first argument is a pointer to the destination, the second is a pointer to
5482the source. The third argument is an integer argument
5483specifying the number of bytes to copy, and the fourth argument is the alignment
5484of the source and destination locations.
5485</p>
5486
5487<p>
5488If the call to this intrinisic has an alignment value that is not 0 or 1, then
5489the caller guarantees that the source and destination pointers are aligned to
5490that boundary.
5491</p>
5492
5493<h5>Semantics:</h5>
5494
5495<p>
5496The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5497location to the destination location, which may overlap. It
5498copies "len" bytes of memory over. If the argument is known to be aligned to
5499some boundary, this can be specified as the fourth argument, otherwise it should
5500be set to 0 or 1.
5501</p>
5502</div>
5503
5504
5505<!-- _______________________________________________________________________ -->
5506<div class="doc_subsubsection">
5507 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5508</div>
5509
5510<div class="doc_text">
5511
5512<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5513<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5514width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5515<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5516 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5517 i8 &lt;len&gt;, i32 &lt;align&gt;)
5518 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5519 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5520 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5521 i32 &lt;len&gt;, i32 &lt;align&gt;)
5522 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5523 i64 &lt;len&gt;, i32 &lt;align&gt;)
5524</pre>
5525
5526<h5>Overview:</h5>
5527
5528<p>
5529The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5530byte value.
5531</p>
5532
5533<p>
5534Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5535does not return a value, and takes an extra alignment argument.
5536</p>
5537
5538<h5>Arguments:</h5>
5539
5540<p>
5541The first argument is a pointer to the destination to fill, the second is the
5542byte value to fill it with, the third argument is an integer
5543argument specifying the number of bytes to fill, and the fourth argument is the
5544known alignment of destination location.
5545</p>
5546
5547<p>
5548If the call to this intrinisic has an alignment value that is not 0 or 1, then
5549the caller guarantees that the destination pointer is aligned to that boundary.
5550</p>
5551
5552<h5>Semantics:</h5>
5553
5554<p>
5555The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5556the
5557destination location. If the argument is known to be aligned to some boundary,
5558this can be specified as the fourth argument, otherwise it should be set to 0 or
55591.
5560</p>
5561</div>
5562
5563
5564<!-- _______________________________________________________________________ -->
5565<div class="doc_subsubsection">
5566 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5567</div>
5568
5569<div class="doc_text">
5570
5571<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5572<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5573floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5574types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5575<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5576 declare float @llvm.sqrt.f32(float %Val)
5577 declare double @llvm.sqrt.f64(double %Val)
5578 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5579 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5580 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5581</pre>
5582
5583<h5>Overview:</h5>
5584
5585<p>
5586The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5587returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5588<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5589negative numbers other than -0.0 (which allows for better optimization, because
5590there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5591defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5592</p>
5593
5594<h5>Arguments:</h5>
5595
5596<p>
5597The argument and return value are floating point numbers of the same type.
5598</p>
5599
5600<h5>Semantics:</h5>
5601
5602<p>
5603This function returns the sqrt of the specified operand if it is a nonnegative
5604floating point number.
5605</p>
5606</div>
5607
5608<!-- _______________________________________________________________________ -->
5609<div class="doc_subsubsection">
5610 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5611</div>
5612
5613<div class="doc_text">
5614
5615<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5616<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5617floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5618types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5619<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5620 declare float @llvm.powi.f32(float %Val, i32 %power)
5621 declare double @llvm.powi.f64(double %Val, i32 %power)
5622 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5623 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5624 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5625</pre>
5626
5627<h5>Overview:</h5>
5628
5629<p>
5630The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5631specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5632multiplications is not defined. When a vector of floating point type is
5633used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5634</p>
5635
5636<h5>Arguments:</h5>
5637
5638<p>
5639The second argument is an integer power, and the first is a value to raise to
5640that power.
5641</p>
5642
5643<h5>Semantics:</h5>
5644
5645<p>
5646This function returns the first value raised to the second power with an
5647unspecified sequence of rounding operations.</p>
5648</div>
5649
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5650<!-- _______________________________________________________________________ -->
5651<div class="doc_subsubsection">
5652 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5653</div>
5654
5655<div class="doc_text">
5656
5657<h5>Syntax:</h5>
5658<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5659floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5660types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5661<pre>
5662 declare float @llvm.sin.f32(float %Val)
5663 declare double @llvm.sin.f64(double %Val)
5664 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5665 declare fp128 @llvm.sin.f128(fp128 %Val)
5666 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5667</pre>
5668
5669<h5>Overview:</h5>
5670
5671<p>
5672The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5673</p>
5674
5675<h5>Arguments:</h5>
5676
5677<p>
5678The argument and return value are floating point numbers of the same type.
5679</p>
5680
5681<h5>Semantics:</h5>
5682
5683<p>
5684This function returns the sine of the specified operand, returning the
5685same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5686conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5687</div>
5688
5689<!-- _______________________________________________________________________ -->
5690<div class="doc_subsubsection">
5691 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5692</div>
5693
5694<div class="doc_text">
5695
5696<h5>Syntax:</h5>
5697<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5698floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5699types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5700<pre>
5701 declare float @llvm.cos.f32(float %Val)
5702 declare double @llvm.cos.f64(double %Val)
5703 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5704 declare fp128 @llvm.cos.f128(fp128 %Val)
5705 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5706</pre>
5707
5708<h5>Overview:</h5>
5709
5710<p>
5711The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5712</p>
5713
5714<h5>Arguments:</h5>
5715
5716<p>
5717The argument and return value are floating point numbers of the same type.
5718</p>
5719
5720<h5>Semantics:</h5>
5721
5722<p>
5723This function returns the cosine of the specified operand, returning the
5724same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5725conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5726</div>
5727
5728<!-- _______________________________________________________________________ -->
5729<div class="doc_subsubsection">
5730 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5731</div>
5732
5733<div class="doc_text">
5734
5735<h5>Syntax:</h5>
5736<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5737floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5738types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5739<pre>
5740 declare float @llvm.pow.f32(float %Val, float %Power)
5741 declare double @llvm.pow.f64(double %Val, double %Power)
5742 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5743 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5744 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5745</pre>
5746
5747<h5>Overview:</h5>
5748
5749<p>
5750The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5751specified (positive or negative) power.
5752</p>
5753
5754<h5>Arguments:</h5>
5755
5756<p>
5757The second argument is a floating point power, and the first is a value to
5758raise to that power.
5759</p>
5760
5761<h5>Semantics:</h5>
5762
5763<p>
5764This function returns the first value raised to the second power,
5765returning the
5766same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5767conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5768</div>
5769
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5770
5771<!-- ======================================================================= -->
5772<div class="doc_subsection">
5773 <a name="int_manip">Bit Manipulation Intrinsics</a>
5774</div>
5775
5776<div class="doc_text">
5777<p>
5778LLVM provides intrinsics for a few important bit manipulation operations.
5779These allow efficient code generation for some algorithms.
5780</p>
5781
5782</div>
5783
5784<!-- _______________________________________________________________________ -->
5785<div class="doc_subsubsection">
5786 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5787</div>
5788
5789<div class="doc_text">
5790
5791<h5>Syntax:</h5>
5792<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5793type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5794<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5795 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5796 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5797 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798</pre>
5799
5800<h5>Overview:</h5>
5801
5802<p>
5803The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5804values with an even number of bytes (positive multiple of 16 bits). These are
5805useful for performing operations on data that is not in the target's native
5806byte order.
5807</p>
5808
5809<h5>Semantics:</h5>
5810
5811<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5812The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5813and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5814intrinsic returns an i32 value that has the four bytes of the input i32
5815swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5816i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5817<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5818additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5819</p>
5820
5821</div>
5822
5823<!-- _______________________________________________________________________ -->
5824<div class="doc_subsubsection">
5825 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5826</div>
5827
5828<div class="doc_text">
5829
5830<h5>Syntax:</h5>
5831<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5832width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5833<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5834 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5835 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5837 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5838 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5839</pre>
5840
5841<h5>Overview:</h5>
5842
5843<p>
5844The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5845value.
5846</p>
5847
5848<h5>Arguments:</h5>
5849
5850<p>
5851The only argument is the value to be counted. The argument may be of any
5852integer type. The return type must match the argument type.
5853</p>
5854
5855<h5>Semantics:</h5>
5856
5857<p>
5858The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5859</p>
5860</div>
5861
5862<!-- _______________________________________________________________________ -->
5863<div class="doc_subsubsection">
5864 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5865</div>
5866
5867<div class="doc_text">
5868
5869<h5>Syntax:</h5>
5870<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5871integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5872<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5873 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5874 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5875 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5876 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5877 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5878</pre>
5879
5880<h5>Overview:</h5>
5881
5882<p>
5883The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5884leading zeros in a variable.
5885</p>
5886
5887<h5>Arguments:</h5>
5888
5889<p>
5890The only argument is the value to be counted. The argument may be of any
5891integer type. The return type must match the argument type.
5892</p>
5893
5894<h5>Semantics:</h5>
5895
5896<p>
5897The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5898in a variable. If the src == 0 then the result is the size in bits of the type
5899of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5900</p>
5901</div>
5902
5903
5904
5905<!-- _______________________________________________________________________ -->
5906<div class="doc_subsubsection">
5907 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5908</div>
5909
5910<div class="doc_text">
5911
5912<h5>Syntax:</h5>
5913<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5914integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5915<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5916 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5917 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5918 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5919 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5920 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5921</pre>
5922
5923<h5>Overview:</h5>
5924
5925<p>
5926The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5927trailing zeros.
5928</p>
5929
5930<h5>Arguments:</h5>
5931
5932<p>
5933The only argument is the value to be counted. The argument may be of any
5934integer type. The return type must match the argument type.
5935</p>
5936
5937<h5>Semantics:</h5>
5938
5939<p>
5940The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5941in a variable. If the src == 0 then the result is the size in bits of the type
5942of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5943</p>
5944</div>
5945
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5946
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5947<!-- ======================================================================= -->
5948<div class="doc_subsection">
5949 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5950</div>
5951
5952<div class="doc_text">
5953<p>
5954LLVM provides intrinsics for some arithmetic with overflow operations.
5955</p>
5956
5957</div>
5958
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5959<!-- _______________________________________________________________________ -->
5960<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5961 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5962</div>
5963
5964<div class="doc_text">
5965
5966<h5>Syntax:</h5>
5967
5968<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5969on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5970
5971<pre>
5972 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5973 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5974 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5975</pre>
5976
5977<h5>Overview:</h5>
5978
5979<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5980a signed addition of the two arguments, and indicate whether an overflow
5981occurred during the signed summation.</p>
5982
5983<h5>Arguments:</h5>
5984
5985<p>The arguments (%a and %b) and the first element of the result structure may
5986be of integer types of any bit width, but they must have the same bit width. The
5987second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5988and <tt>%b</tt> are the two values that will undergo signed addition.</p>
5989
5990<h5>Semantics:</h5>
5991
5992<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5993a signed addition of the two variables. They return a structure &mdash; the
5994first element of which is the signed summation, and the second element of which
5995is a bit specifying if the signed summation resulted in an overflow.</p>
5996
5997<h5>Examples:</h5>
5998<pre>
5999 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6000 %sum = extractvalue {i32, i1} %res, 0
6001 %obit = extractvalue {i32, i1} %res, 1
6002 br i1 %obit, label %overflow, label %normal
6003</pre>
6004
6005</div>
6006
6007<!-- _______________________________________________________________________ -->
6008<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6009 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6010</div>
6011
6012<div class="doc_text">
6013
6014<h5>Syntax:</h5>
6015
6016<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6017on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6018
6019<pre>
6020 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6021 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6022 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6023</pre>
6024
6025<h5>Overview:</h5>
6026
6027<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6028an unsigned addition of the two arguments, and indicate whether a carry occurred
6029during the unsigned summation.</p>
6030
6031<h5>Arguments:</h5>
6032
6033<p>The arguments (%a and %b) and the first element of the result structure may
6034be of integer types of any bit width, but they must have the same bit width. The
6035second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6036and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6037
6038<h5>Semantics:</h5>
6039
6040<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6041an unsigned addition of the two arguments. They return a structure &mdash; the
6042first element of which is the sum, and the second element of which is a bit
6043specifying if the unsigned summation resulted in a carry.</p>
6044
6045<h5>Examples:</h5>
6046<pre>
6047 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6048 %sum = extractvalue {i32, i1} %res, 0
6049 %obit = extractvalue {i32, i1} %res, 1
6050 br i1 %obit, label %carry, label %normal
6051</pre>
6052
6053</div>
6054
6055<!-- _______________________________________________________________________ -->
6056<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6057 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6058</div>
6059
6060<div class="doc_text">
6061
6062<h5>Syntax:</h5>
6063
6064<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6065on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6066
6067<pre>
6068 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6069 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6070 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6071</pre>
6072
6073<h5>Overview:</h5>
6074
6075<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6076a signed subtraction of the two arguments, and indicate whether an overflow
6077occurred during the signed subtraction.</p>
6078
6079<h5>Arguments:</h5>
6080
6081<p>The arguments (%a and %b) and the first element of the result structure may
6082be of integer types of any bit width, but they must have the same bit width. The
6083second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6084and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6085
6086<h5>Semantics:</h5>
6087
6088<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6089a signed subtraction of the two arguments. They return a structure &mdash; the
6090first element of which is the subtraction, and the second element of which is a bit
6091specifying if the signed subtraction resulted in an overflow.</p>
6092
6093<h5>Examples:</h5>
6094<pre>
6095 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6096 %sum = extractvalue {i32, i1} %res, 0
6097 %obit = extractvalue {i32, i1} %res, 1
6098 br i1 %obit, label %overflow, label %normal
6099</pre>
6100
6101</div>
6102
6103<!-- _______________________________________________________________________ -->
6104<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6105 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6106</div>
6107
6108<div class="doc_text">
6109
6110<h5>Syntax:</h5>
6111
6112<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6113on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6114
6115<pre>
6116 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6117 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6118 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6119</pre>
6120
6121<h5>Overview:</h5>
6122
6123<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6124an unsigned subtraction of the two arguments, and indicate whether an overflow
6125occurred during the unsigned subtraction.</p>
6126
6127<h5>Arguments:</h5>
6128
6129<p>The arguments (%a and %b) and the first element of the result structure may
6130be of integer types of any bit width, but they must have the same bit width. The
6131second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6132and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6133
6134<h5>Semantics:</h5>
6135
6136<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6137an unsigned subtraction of the two arguments. They return a structure &mdash; the
6138first element of which is the subtraction, and the second element of which is a bit
6139specifying if the unsigned subtraction resulted in an overflow.</p>
6140
6141<h5>Examples:</h5>
6142<pre>
6143 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6144 %sum = extractvalue {i32, i1} %res, 0
6145 %obit = extractvalue {i32, i1} %res, 1
6146 br i1 %obit, label %overflow, label %normal
6147</pre>
6148
6149</div>
6150
6151<!-- _______________________________________________________________________ -->
6152<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6153 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6154</div>
6155
6156<div class="doc_text">
6157
6158<h5>Syntax:</h5>
6159
6160<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6161on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6162
6163<pre>
6164 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6165 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6166 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6167</pre>
6168
6169<h5>Overview:</h5>
6170
6171<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6172a signed multiplication of the two arguments, and indicate whether an overflow
6173occurred during the signed multiplication.</p>
6174
6175<h5>Arguments:</h5>
6176
6177<p>The arguments (%a and %b) and the first element of the result structure may
6178be of integer types of any bit width, but they must have the same bit width. The
6179second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6180and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6181
6182<h5>Semantics:</h5>
6183
6184<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6185a signed multiplication of the two arguments. They return a structure &mdash;
6186the first element of which is the multiplication, and the second element of
6187which is a bit specifying if the signed multiplication resulted in an
6188overflow.</p>
6189
6190<h5>Examples:</h5>
6191<pre>
6192 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6193 %sum = extractvalue {i32, i1} %res, 0
6194 %obit = extractvalue {i32, i1} %res, 1
6195 br i1 %obit, label %overflow, label %normal
6196</pre>
6197
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6198</div>
6199
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6200<!-- _______________________________________________________________________ -->
6201<div class="doc_subsubsection">
6202 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6203</div>
6204
6205<div class="doc_text">
6206
6207<h5>Syntax:</h5>
6208
6209<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6210on any integer bit width.</p>
6211
6212<pre>
6213 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6214 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6215 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6216</pre>
6217
6218<h5>Overview:</h5>
6219
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6220<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6221a unsigned multiplication of the two arguments, and indicate whether an overflow
6222occurred during the unsigned multiplication.</p>
6223
6224<h5>Arguments:</h5>
6225
6226<p>The arguments (%a and %b) and the first element of the result structure may
6227be of integer types of any bit width, but they must have the same bit width. The
6228second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6229and <tt>%b</tt> are the two values that will undergo unsigned
6230multiplication.</p>
6231
6232<h5>Semantics:</h5>
6233
6234<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6235an unsigned multiplication of the two arguments. They return a structure &mdash;
6236the first element of which is the multiplication, and the second element of
6237which is a bit specifying if the unsigned multiplication resulted in an
6238overflow.</p>
6239
6240<h5>Examples:</h5>
6241<pre>
6242 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6243 %sum = extractvalue {i32, i1} %res, 0
6244 %obit = extractvalue {i32, i1} %res, 1
6245 br i1 %obit, label %overflow, label %normal
6246</pre>
6247
6248</div>
6249
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6250<!-- ======================================================================= -->
6251<div class="doc_subsection">
6252 <a name="int_debugger">Debugger Intrinsics</a>
6253</div>
6254
6255<div class="doc_text">
6256<p>
6257The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6258are described in the <a
6259href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6260Debugging</a> document.
6261</p>
6262</div>
6263
6264
6265<!-- ======================================================================= -->
6266<div class="doc_subsection">
6267 <a name="int_eh">Exception Handling Intrinsics</a>
6268</div>
6269
6270<div class="doc_text">
6271<p> The LLVM exception handling intrinsics (which all start with
6272<tt>llvm.eh.</tt> prefix), are described in the <a
6273href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6274Handling</a> document. </p>
6275</div>
6276
6277<!-- ======================================================================= -->
6278<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6279 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6280</div>
6281
6282<div class="doc_text">
6283<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6284 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6285 the <tt>nest</tt> attribute, from a function. The result is a callable
6286 function pointer lacking the nest parameter - the caller does not need
6287 to provide a value for it. Instead, the value to use is stored in
6288 advance in a "trampoline", a block of memory usually allocated
6289 on the stack, which also contains code to splice the nest value into the
6290 argument list. This is used to implement the GCC nested function address
6291 extension.
6292</p>
6293<p>
6294 For example, if the function is
6295 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6296 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6297<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6298 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6299 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6300 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6301 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6302</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6303 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6304 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6305</div>
6306
6307<!-- _______________________________________________________________________ -->
6308<div class="doc_subsubsection">
6309 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6310</div>
6311<div class="doc_text">
6312<h5>Syntax:</h5>
6313<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6314declare 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]6315</pre>
6316<h5>Overview:</h5>
6317<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6318 This fills the memory pointed to by <tt>tramp</tt> with code
6319 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6320</p>
6321<h5>Arguments:</h5>
6322<p>
6323 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6324 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6325 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6326 intrinsic. Note that the size and the alignment are target-specific - LLVM
6327 currently provides no portable way of determining them, so a front-end that
6328 generates this intrinsic needs to have some target-specific knowledge.
6329 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6330</p>
6331<h5>Semantics:</h5>
6332<p>
6333 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6334 dependent code, turning it into a function. A pointer to this function is
6335 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6336 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6337 before being called. The new function's signature is the same as that of
6338 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6339 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6340 of pointer type. Calling the new function is equivalent to calling
6341 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6342 missing <tt>nest</tt> argument. If, after calling
6343 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6344 modified, then the effect of any later call to the returned function pointer is
6345 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6346</p>
6347</div>
6348
6349<!-- ======================================================================= -->
6350<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6351 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6352</div>
6353
6354<div class="doc_text">
6355<p>
6356 These intrinsic functions expand the "universal IR" of LLVM to represent
6357 hardware constructs for atomic operations and memory synchronization. This
6358 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6359 is aimed at a low enough level to allow any programming models or APIs
6360 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6361 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6362 hardware behavior. Just as hardware provides a "universal IR" for source
6363 languages, it also provides a starting point for developing a "universal"
6364 atomic operation and synchronization IR.
6365</p>
6366<p>
6367 These do <em>not</em> form an API such as high-level threading libraries,
6368 software transaction memory systems, atomic primitives, and intrinsic
6369 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6370 application libraries. The hardware interface provided by LLVM should allow
6371 a clean implementation of all of these APIs and parallel programming models.
6372 No one model or paradigm should be selected above others unless the hardware
6373 itself ubiquitously does so.
6374
6375</p>
6376</div>
6377
6378<!-- _______________________________________________________________________ -->
6379<div class="doc_subsubsection">
6380 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6381</div>
6382<div class="doc_text">
6383<h5>Syntax:</h5>
6384<pre>
6385declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6386i1 &lt;device&gt; )
6387
6388</pre>
6389<h5>Overview:</h5>
6390<p>
6391 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6392 specific pairs of memory access types.
6393</p>
6394<h5>Arguments:</h5>
6395<p>
6396 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6397 The first four arguments enables a specific barrier as listed below. The fith
6398 argument specifies that the barrier applies to io or device or uncached memory.
6399
6400</p>
6401 <ul>
6402 <li><tt>ll</tt>: load-load barrier</li>
6403 <li><tt>ls</tt>: load-store barrier</li>
6404 <li><tt>sl</tt>: store-load barrier</li>
6405 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6406 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6407 </ul>
6408<h5>Semantics:</h5>
6409<p>
6410 This intrinsic causes the system to enforce some ordering constraints upon
6411 the loads and stores of the program. This barrier does not indicate
6412 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6413 which they occur. For any of the specified pairs of load and store operations
6414 (f.ex. load-load, or store-load), all of the first operations preceding the
6415 barrier will complete before any of the second operations succeeding the
6416 barrier begin. Specifically the semantics for each pairing is as follows:
6417</p>
6418 <ul>
6419 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6420 after the barrier begins.</li>
6421
6422 <li><tt>ls</tt>: All loads before the barrier must complete before any
6423 store after the barrier begins.</li>
6424 <li><tt>ss</tt>: All stores before the barrier must complete before any
6425 store after the barrier begins.</li>
6426 <li><tt>sl</tt>: All stores before the barrier must complete before any
6427 load after the barrier begins.</li>
6428 </ul>
6429<p>
6430 These semantics are applied with a logical "and" behavior when more than one
6431 is enabled in a single memory barrier intrinsic.
6432</p>
6433<p>
6434 Backends may implement stronger barriers than those requested when they do not
6435 support as fine grained a barrier as requested. Some architectures do not
6436 need all types of barriers and on such architectures, these become noops.
6437</p>
6438<h5>Example:</h5>
6439<pre>
6440%ptr = malloc i32
6441 store i32 4, %ptr
6442
6443%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6444 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6445 <i>; guarantee the above finishes</i>
6446 store i32 8, %ptr <i>; before this begins</i>
6447</pre>
6448</div>
6449
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6450<!-- _______________________________________________________________________ -->
6451<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6452 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6453</div>
6454<div class="doc_text">
6455<h5>Syntax:</h5>
6456<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6457 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6458 any integer bit width and for different address spaces. Not all targets
6459 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6460
6461<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6462declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6463declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6464declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6465declare 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]6466
6467</pre>
6468<h5>Overview:</h5>
6469<p>
6470 This loads a value in memory and compares it to a given value. If they are
6471 equal, it stores a new value into the memory.
6472</p>
6473<h5>Arguments:</h5>
6474<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6475 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6476 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6477 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6478 this integer type. While any bit width integer may be used, targets may only
6479 lower representations they support in hardware.
6480
6481</p>
6482<h5>Semantics:</h5>
6483<p>
6484 This entire intrinsic must be executed atomically. It first loads the value
6485 in memory pointed to by <tt>ptr</tt> and compares it with the value
6486 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6487 loaded value is yielded in all cases. This provides the equivalent of an
6488 atomic compare-and-swap operation within the SSA framework.
6489</p>
6490<h5>Examples:</h5>
6491
6492<pre>
6493%ptr = malloc i32
6494 store i32 4, %ptr
6495
6496%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6497%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6498 <i>; yields {i32}:result1 = 4</i>
6499%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6500%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6501
6502%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6503%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6504 <i>; yields {i32}:result2 = 8</i>
6505%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6506
6507%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6508</pre>
6509</div>
6510
6511<!-- _______________________________________________________________________ -->
6512<div class="doc_subsubsection">
6513 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6514</div>
6515<div class="doc_text">
6516<h5>Syntax:</h5>
6517
6518<p>
6519 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6520 integer bit width. Not all targets support all bit widths however.</p>
6521<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6522declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6523declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6524declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6525declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6526
6527</pre>
6528<h5>Overview:</h5>
6529<p>
6530 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6531 the value from memory. It then stores the value in <tt>val</tt> in the memory
6532 at <tt>ptr</tt>.
6533</p>
6534<h5>Arguments:</h5>
6535
6536<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6537 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6538 <tt>val</tt> argument and the result must be integers of the same bit width.
6539 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6540 integer type. The targets may only lower integer representations they
6541 support.
6542</p>
6543<h5>Semantics:</h5>
6544<p>
6545 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6546 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6547 equivalent of an atomic swap operation within the SSA framework.
6548
6549</p>
6550<h5>Examples:</h5>
6551<pre>
6552%ptr = malloc i32
6553 store i32 4, %ptr
6554
6555%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6556%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6557 <i>; yields {i32}:result1 = 4</i>
6558%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6559%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6560
6561%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6562%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6563 <i>; yields {i32}:result2 = 8</i>
6564
6565%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6566%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6567</pre>
6568</div>
6569
6570<!-- _______________________________________________________________________ -->
6571<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6572 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6573
6574</div>
6575<div class="doc_text">
6576<h5>Syntax:</h5>
6577<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6578 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6579 integer bit width. Not all targets support all bit widths however.</p>
6580<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6581declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6582declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6583declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6584declare 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]6585
6586</pre>
6587<h5>Overview:</h5>
6588<p>
6589 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6590 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6591</p>
6592<h5>Arguments:</h5>
6593<p>
6594
6595 The intrinsic takes two arguments, the first a pointer to an integer value
6596 and the second an integer value. The result is also an integer value. These
6597 integer types can have any bit width, but they must all have the same bit
6598 width. The targets may only lower integer representations they support.
6599</p>
6600<h5>Semantics:</h5>
6601<p>
6602 This intrinsic does a series of operations atomically. It first loads the
6603 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6604 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6605</p>
6606
6607<h5>Examples:</h5>
6608<pre>
6609%ptr = malloc i32
6610 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6611%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6612 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6613%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6614 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6615%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6616 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6617%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6618</pre>
6619</div>
6620
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6621<!-- _______________________________________________________________________ -->
6622<div class="doc_subsubsection">
6623 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6624
6625</div>
6626<div class="doc_text">
6627<h5>Syntax:</h5>
6628<p>
6629 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6630 any integer bit width and for different address spaces. Not all targets
6631 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6632<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6633declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6634declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6635declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6636declare 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]6637
6638</pre>
6639<h5>Overview:</h5>
6640<p>
6641 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6642 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6643</p>
6644<h5>Arguments:</h5>
6645<p>
6646
6647 The intrinsic takes two arguments, the first a pointer to an integer value
6648 and the second an integer value. The result is also an integer value. These
6649 integer types can have any bit width, but they must all have the same bit
6650 width. The targets may only lower integer representations they support.
6651</p>
6652<h5>Semantics:</h5>
6653<p>
6654 This intrinsic does a series of operations atomically. It first loads the
6655 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6656 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6657</p>
6658
6659<h5>Examples:</h5>
6660<pre>
6661%ptr = malloc i32
6662 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6663%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6664 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6665%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6666 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6667%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6668 <i>; yields {i32}:result3 = 2</i>
6669%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6670</pre>
6671</div>
6672
6673<!-- _______________________________________________________________________ -->
6674<div class="doc_subsubsection">
6675 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6676 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6677 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6678 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6679
6680</div>
6681<div class="doc_text">
6682<h5>Syntax:</h5>
6683<p>
6684 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6685 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6686 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6687 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6688<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6689declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6690declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6691declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6692declare 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]6693
6694</pre>
6695
6696<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6697declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6698declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6699declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6700declare 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]6701
6702</pre>
6703
6704<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6705declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6706declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6707declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6708declare 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]6709
6710</pre>
6711
6712<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6713declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6714declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6715declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6716declare 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]6717
6718</pre>
6719<h5>Overview:</h5>
6720<p>
6721 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6722 the value stored in memory at <tt>ptr</tt>. It yields the original value
6723 at <tt>ptr</tt>.
6724</p>
6725<h5>Arguments:</h5>
6726<p>
6727
6728 These intrinsics take two arguments, the first a pointer to an integer value
6729 and the second an integer value. The result is also an integer value. These
6730 integer types can have any bit width, but they must all have the same bit
6731 width. The targets may only lower integer representations they support.
6732</p>
6733<h5>Semantics:</h5>
6734<p>
6735 These intrinsics does a series of operations atomically. They first load the
6736 value stored at <tt>ptr</tt>. They then do the bitwise operation
6737 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6738 value stored at <tt>ptr</tt>.
6739</p>
6740
6741<h5>Examples:</h5>
6742<pre>
6743%ptr = malloc i32
6744 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6745%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6746 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6747%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6748 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6749%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6750 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6751%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6752 <i>; yields {i32}:result3 = FF</i>
6753%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6754</pre>
6755</div>
6756
6757
6758<!-- _______________________________________________________________________ -->
6759<div class="doc_subsubsection">
6760 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6761 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6762 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6763 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6764
6765</div>
6766<div class="doc_text">
6767<h5>Syntax:</h5>
6768<p>
6769 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6770 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6771 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6772 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6773 support all bit widths however.</p>
6774<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6775declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6776declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6777declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6778declare 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]6779
6780</pre>
6781
6782<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6783declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6784declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6785declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6786declare 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]6787
6788</pre>
6789
6790<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6791declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6792declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6793declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6794declare 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]6795
6796</pre>
6797
6798<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6799declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6800declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6801declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6802declare 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]6803
6804</pre>
6805<h5>Overview:</h5>
6806<p>
6807 These intrinsics takes the signed or unsigned minimum or maximum of
6808 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6809 original value at <tt>ptr</tt>.
6810</p>
6811<h5>Arguments:</h5>
6812<p>
6813
6814 These intrinsics take two arguments, the first a pointer to an integer value
6815 and the second an integer value. The result is also an integer value. These
6816 integer types can have any bit width, but they must all have the same bit
6817 width. The targets may only lower integer representations they support.
6818</p>
6819<h5>Semantics:</h5>
6820<p>
6821 These intrinsics does a series of operations atomically. They first load the
6822 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6823 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6824 the original value stored at <tt>ptr</tt>.
6825</p>
6826
6827<h5>Examples:</h5>
6828<pre>
6829%ptr = malloc i32
6830 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6831%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6832 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6833%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6834 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6835%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6836 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6837%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6838 <i>; yields {i32}:result3 = 8</i>
6839%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6840</pre>
6841</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6842
6843<!-- ======================================================================= -->
6844<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6845 <a name="int_general">General Intrinsics</a>
6846</div>
6847
6848<div class="doc_text">
6849<p> This class of intrinsics is designed to be generic and has
6850no specific purpose. </p>
6851</div>
6852
6853<!-- _______________________________________________________________________ -->
6854<div class="doc_subsubsection">
6855 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6856</div>
6857
6858<div class="doc_text">
6859
6860<h5>Syntax:</h5>
6861<pre>
6862 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6863</pre>
6864
6865<h5>Overview:</h5>
6866
6867<p>
6868The '<tt>llvm.var.annotation</tt>' intrinsic
6869</p>
6870
6871<h5>Arguments:</h5>
6872
6873<p>
6874The first argument is a pointer to a value, the second is a pointer to a
6875global string, the third is a pointer to a global string which is the source
6876file name, and the last argument is the line number.
6877</p>
6878
6879<h5>Semantics:</h5>
6880
6881<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6882This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6883This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6884annotations. These have no other defined use, they are ignored by code
6885generation and optimization.
6886</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6887</div>
6888
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6889<!-- _______________________________________________________________________ -->
6890<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6891 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6892</div>
6893
6894<div class="doc_text">
6895
6896<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6897<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6898any integer bit width.
6899</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6900<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6901 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6902 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6903 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6904 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6905 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]6906</pre>
6907
6908<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6909
6910<p>
6911The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6912</p>
6913
6914<h5>Arguments:</h5>
6915
6916<p>
6917The first argument is an integer value (result of some expression),
6918the second is a pointer to a global string, the third is a pointer to a global
6919string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6920It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6921</p>
6922
6923<h5>Semantics:</h5>
6924
6925<p>
6926This intrinsic allows annotations to be put on arbitrary expressions
6927with arbitrary strings. This can be useful for special purpose optimizations
6928that want to look for these annotations. These have no other defined use, they
6929are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6930</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6931</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6932
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6933<!-- _______________________________________________________________________ -->
6934<div class="doc_subsubsection">
6935 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6936</div>
6937
6938<div class="doc_text">
6939
6940<h5>Syntax:</h5>
6941<pre>
6942 declare void @llvm.trap()
6943</pre>
6944
6945<h5>Overview:</h5>
6946
6947<p>
6948The '<tt>llvm.trap</tt>' intrinsic
6949</p>
6950
6951<h5>Arguments:</h5>
6952
6953<p>
6954None
6955</p>
6956
6957<h5>Semantics:</h5>
6958
6959<p>
6960This intrinsics is lowered to the target dependent trap instruction. If the
6961target does not have a trap instruction, this intrinsic will be lowered to the
6962call of the abort() function.
6963</p>
6964</div>
6965
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6966<!-- _______________________________________________________________________ -->
6967<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6968 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6969</div>
6970<div class="doc_text">
6971<h5>Syntax:</h5>
6972<pre>
6973declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6974
6975</pre>
6976<h5>Overview:</h5>
6977<p>
6978 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6979 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6980 it is placed on the stack before local variables.
6981</p>
6982<h5>Arguments:</h5>
6983<p>
6984 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6985 first argument is the value loaded from the stack guard
6986 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6987 has enough space to hold the value of the guard.
6988</p>
6989<h5>Semantics:</h5>
6990<p>
6991 This intrinsic causes the prologue/epilogue inserter to force the position of
6992 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6993 stack. This is to ensure that if a local variable on the stack is overwritten,
6994 it will destroy the value of the guard. When the function exits, the guard on
6995 the stack is checked against the original guard. If they're different, then
6996 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6997</p>
6998</div>
6999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7000<!-- *********************************************************************** -->
7001<hr>
7002<address>
7003 <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]7007
7008 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7009 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7010 Last modified: $Date$
7011</address>
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