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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 66bd777e9009fd6a606532f9ed96745e86f3937c / . / 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>
92 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
93 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
94 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
95 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
96 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
97 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
98 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
99 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
100 </ol>
101 </li>
102 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
103 <ol>
104 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
105 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
106 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
107 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
108 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
109 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
110 </ol>
111 </li>
112 <li><a href="#vectorops">Vector Operations</a>
113 <ol>
114 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
115 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
116 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
117 </ol>
118 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]119 <li><a href="#aggregateops">Aggregate Operations</a>
120 <ol>
121 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
122 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
123 </ol>
124 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]125 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
126 <ol>
127 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
128 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
129 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
130 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
131 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
132 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
133 </ol>
134 </li>
135 <li><a href="#convertops">Conversion Operations</a>
136 <ol>
137 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
138 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
139 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
141 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
142 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
143 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
144 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
145 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
146 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
147 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
148 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
149 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]150 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]151 <li><a href="#otherops">Other Operations</a>
152 <ol>
153 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
154 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]155 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
156 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]157 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
158 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
159 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
160 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
161 </ol>
162 </li>
163 </ol>
164 </li>
165 <li><a href="#intrinsics">Intrinsic Functions</a>
166 <ol>
167 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
168 <ol>
169 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
170 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
171 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
172 </ol>
173 </li>
174 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
175 <ol>
176 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
177 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
178 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
179 </ol>
180 </li>
181 <li><a href="#int_codegen">Code Generator Intrinsics</a>
182 <ol>
183 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
184 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
185 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
186 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
187 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
188 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
189 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
190 </ol>
191 </li>
192 <li><a href="#int_libc">Standard C Library Intrinsics</a>
193 <ol>
194 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]199 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
201 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]202 </ol>
203 </li>
204 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
205 <ol>
206 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
207 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
210 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
211 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
212 </ol>
213 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]214 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
215 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]216 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
219 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
220 <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]221 <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]222 </ol>
223 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]224 <li><a href="#int_debugger">Debugger intrinsics</a></li>
225 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]226 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]227 <ol>
228 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]229 </ol>
230 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]231 <li><a href="#int_atomics">Atomic intrinsics</a>
232 <ol>
233 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
234 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
235 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
236 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
237 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
238 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
239 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
240 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
241 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
242 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
243 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
244 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
245 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
246 </ol>
247 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]248 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]249 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]250 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]251 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]252 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]253 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]254 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]255 '<tt>llvm.trap</tt>' Intrinsic</a></li>
256 <li><a href="#int_stackprotector">
257 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]258 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]259 </li>
260 </ol>
261 </li>
262</ol>
263
264<div class="doc_author">
265 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
266 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
267</div>
268
269<!-- *********************************************************************** -->
270<div class="doc_section"> <a name="abstract">Abstract </a></div>
271<!-- *********************************************************************** -->
272
273<div class="doc_text">
274<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]275LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]276type safety, low-level operations, flexibility, and the capability of
277representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]278representation used throughout all phases of the LLVM compilation
279strategy.</p>
280</div>
281
282<!-- *********************************************************************** -->
283<div class="doc_section"> <a name="introduction">Introduction</a> </div>
284<!-- *********************************************************************** -->
285
286<div class="doc_text">
287
288<p>The LLVM code representation is designed to be used in three
289different forms: as an in-memory compiler IR, as an on-disk bitcode
290representation (suitable for fast loading by a Just-In-Time compiler),
291and as a human readable assembly language representation. This allows
292LLVM to provide a powerful intermediate representation for efficient
293compiler transformations and analysis, while providing a natural means
294to debug and visualize the transformations. The three different forms
295of LLVM are all equivalent. This document describes the human readable
296representation and notation.</p>
297
298<p>The LLVM representation aims to be light-weight and low-level
299while being expressive, typed, and extensible at the same time. It
300aims to be a "universal IR" of sorts, by being at a low enough level
301that high-level ideas may be cleanly mapped to it (similar to how
302microprocessors are "universal IR's", allowing many source languages to
303be mapped to them). By providing type information, LLVM can be used as
304the target of optimizations: for example, through pointer analysis, it
305can be proven that a C automatic variable is never accessed outside of
306the current function... allowing it to be promoted to a simple SSA
307value instead of a memory location.</p>
308
309</div>
310
311<!-- _______________________________________________________________________ -->
312<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
313
314<div class="doc_text">
315
316<p>It is important to note that this document describes 'well formed'
317LLVM assembly language. There is a difference between what the parser
318accepts and what is considered 'well formed'. For example, the
319following instruction is syntactically okay, but not well formed:</p>
320
321<div class="doc_code">
322<pre>
323%x = <a href="#i_add">add</a> i32 1, %x
324</pre>
325</div>
326
327<p>...because the definition of <tt>%x</tt> does not dominate all of
328its uses. The LLVM infrastructure provides a verification pass that may
329be used to verify that an LLVM module is well formed. This pass is
330automatically run by the parser after parsing input assembly and by
331the optimizer before it outputs bitcode. The violations pointed out
332by the verifier pass indicate bugs in transformation passes or input to
333the parser.</p>
334</div>
335
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]336<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]337
338<!-- *********************************************************************** -->
339<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
340<!-- *********************************************************************** -->
341
342<div class="doc_text">
343
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]344 <p>LLVM identifiers come in two basic types: global and local. Global
345 identifiers (functions, global variables) begin with the @ character. Local
346 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]347 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]348
349<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]350 <li>Named values are represented as a string of characters with their prefix.
351 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
352 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]353 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]354 with quotes. Special characters may be escaped using "\xx" where xx is the
355 ASCII code for the character in hexadecimal. In this way, any character can
356 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]357
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]358 <li>Unnamed values are represented as an unsigned numeric value with their
359 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]360
361 <li>Constants, which are described in a <a href="#constants">section about
362 constants</a>, below.</li>
363</ol>
364
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]365<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]366don't need to worry about name clashes with reserved words, and the set of
367reserved words may be expanded in the future without penalty. Additionally,
368unnamed identifiers allow a compiler to quickly come up with a temporary
369variable without having to avoid symbol table conflicts.</p>
370
371<p>Reserved words in LLVM are very similar to reserved words in other
372languages. There are keywords for different opcodes
373('<tt><a href="#i_add">add</a></tt>',
374 '<tt><a href="#i_bitcast">bitcast</a></tt>',
375 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
376href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
377and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]378none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]379
380<p>Here is an example of LLVM code to multiply the integer variable
381'<tt>%X</tt>' by 8:</p>
382
383<p>The easy way:</p>
384
385<div class="doc_code">
386<pre>
387%result = <a href="#i_mul">mul</a> i32 %X, 8
388</pre>
389</div>
390
391<p>After strength reduction:</p>
392
393<div class="doc_code">
394<pre>
395%result = <a href="#i_shl">shl</a> i32 %X, i8 3
396</pre>
397</div>
398
399<p>And the hard way:</p>
400
401<div class="doc_code">
402<pre>
403<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
404<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
405%result = <a href="#i_add">add</a> i32 %1, %1
406</pre>
407</div>
408
409<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
410important lexical features of LLVM:</p>
411
412<ol>
413
414 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
415 line.</li>
416
417 <li>Unnamed temporaries are created when the result of a computation is not
418 assigned to a named value.</li>
419
420 <li>Unnamed temporaries are numbered sequentially</li>
421
422</ol>
423
424<p>...and it also shows a convention that we follow in this document. When
425demonstrating instructions, we will follow an instruction with a comment that
426defines the type and name of value produced. Comments are shown in italic
427text.</p>
428
429</div>
430
431<!-- *********************************************************************** -->
432<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
433<!-- *********************************************************************** -->
434
435<!-- ======================================================================= -->
436<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
437</div>
438
439<div class="doc_text">
440
441<p>LLVM programs are composed of "Module"s, each of which is a
442translation unit of the input programs. Each module consists of
443functions, global variables, and symbol table entries. Modules may be
444combined together with the LLVM linker, which merges function (and
445global variable) definitions, resolves forward declarations, and merges
446symbol table entries. Here is an example of the "hello world" module:</p>
447
448<div class="doc_code">
449<pre><i>; Declare the string constant as a global constant...</i>
450<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
451 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
452
453<i>; External declaration of the puts function</i>
454<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
455
456<i>; Definition of main function</i>
457define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]458 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]459 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]460 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]461
462 <i>; Call puts function to write out the string to stdout...</i>
463 <a
464 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
465 <a
466 href="#i_ret">ret</a> i32 0<br>}<br>
467</pre>
468</div>
469
470<p>This example is made up of a <a href="#globalvars">global variable</a>
471named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
472function, and a <a href="#functionstructure">function definition</a>
473for "<tt>main</tt>".</p>
474
475<p>In general, a module is made up of a list of global values,
476where both functions and global variables are global values. Global values are
477represented by a pointer to a memory location (in this case, a pointer to an
478array of char, and a pointer to a function), and have one of the following <a
479href="#linkage">linkage types</a>.</p>
480
481</div>
482
483<!-- ======================================================================= -->
484<div class="doc_subsection">
485 <a name="linkage">Linkage Types</a>
486</div>
487
488<div class="doc_text">
489
490<p>
491All Global Variables and Functions have one of the following types of linkage:
492</p>
493
494<dl>
495
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]496 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
497
498 <dd>Global values with private linkage are only directly accessible by
499 objects in the current module. In particular, linking code into a module with
500 an private global value may cause the private to be renamed as necessary to
501 avoid collisions. Because the symbol is private to the module, all
502 references can be updated. This doesn't show up in any symbol table in the
503 object file.
504 </dd>
505
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]506 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]507
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]508 <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]509 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]510 '<tt>static</tt>' keyword in C.
511 </dd>
512
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]513 <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
514 </dt>
515
516 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
517 into the object file corresponding to the LLVM module. They exist to
518 allow inlining and other optimizations to take place given knowledge of the
519 definition of the global, which is known to be somewhere outside the module.
520 Globals with <tt>available_externally</tt> linkage are allowed to be discarded
521 at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
522 type is only allowed on definitions, not declarations.</dd>
523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]524 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
525
526 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
527 the same name when linkage occurs. This is typically used to implement
528 inline functions, templates, or other code which must be generated in each
529 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
530 allowed to be discarded.
531 </dd>
532
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]533 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
534
535 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
536 linkage, except that unreferenced <tt>common</tt> globals may not be
537 discarded. This is used for globals that may be emitted in multiple
538 translation units, but that are not guaranteed to be emitted into every
539 translation unit that uses them. One example of this is tentative
540 definitions in C, such as "<tt>int X;</tt>" at global scope.
541 </dd>
542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]543 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
544
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]545 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
546 that some targets may choose to emit different assembly sequences for them
547 for target-dependent reasons. This is used for globals that are declared
548 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]549 </dd>
550
551 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
552
553 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
554 pointer to array type. When two global variables with appending linkage are
555 linked together, the two global arrays are appended together. This is the
556 LLVM, typesafe, equivalent of having the system linker append together
557 "sections" with identical names when .o files are linked.
558 </dd>
559
560 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]561
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]562 <dd>The semantics of this linkage follow the ELF object file model: the
563 symbol is weak until linked, if not linked, the symbol becomes null instead
564 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]565 </dd>
566
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]567 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]568 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]569 <dd>Some languages allow differing globals to be merged, such as two
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]570 functions with different semantics. Other languages, such as <tt>C++</tt>,
571 ensure that only equivalent globals are ever merged (the "one definition
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]572 rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Duncan Sandsb95df792009-03-11 20:14:15 +0000[diff] [blame]573 and <tt>weak_odr</tt> linkage types to indicate that the global will only
574 be merged with equivalent globals. These linkage types are otherwise the
575 same as their non-<tt>odr</tt> versions.
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]576 </dd>
577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]578 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
579
580 <dd>If none of the above identifiers are used, the global is externally
581 visible, meaning that it participates in linkage and can be used to resolve
582 external symbol references.
583 </dd>
584</dl>
585
586 <p>
587 The next two types of linkage are targeted for Microsoft Windows platform
588 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]589 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]590 </p>
591
592 <dl>
593 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
594
595 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
596 or variable via a global pointer to a pointer that is set up by the DLL
597 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]598 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]599 </dd>
600
601 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
602
603 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
604 pointer to a pointer in a DLL, so that it can be referenced with the
605 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]606 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]607 name.
608 </dd>
609
610</dl>
611
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]612<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]613variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
614variable and was linked with this one, one of the two would be renamed,
615preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
616external (i.e., lacking any linkage declarations), they are accessible
617outside of the current module.</p>
618<p>It is illegal for a function <i>declaration</i>
Duncan Sands565f65d2009-03-11 08:08:06 +0000[diff] [blame]619to have any linkage type other than "externally visible", <tt>dllimport</tt>
620or <tt>extern_weak</tt>.</p>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]621<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
622or <tt>weak_odr</tt> linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]623</div>
624
625<!-- ======================================================================= -->
626<div class="doc_subsection">
627 <a name="callingconv">Calling Conventions</a>
628</div>
629
630<div class="doc_text">
631
632<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
633and <a href="#i_invoke">invokes</a> can all have an optional calling convention
634specified for the call. The calling convention of any pair of dynamic
635caller/callee must match, or the behavior of the program is undefined. The
636following calling conventions are supported by LLVM, and more may be added in
637the future:</p>
638
639<dl>
640 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
641
642 <dd>This calling convention (the default if no other calling convention is
643 specified) matches the target C calling conventions. This calling convention
644 supports varargs function calls and tolerates some mismatch in the declared
645 prototype and implemented declaration of the function (as does normal C).
646 </dd>
647
648 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
649
650 <dd>This calling convention attempts to make calls as fast as possible
651 (e.g. by passing things in registers). This calling convention allows the
652 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]653 without having to conform to an externally specified ABI (Application Binary
654 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]655 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
656 supported. This calling convention does not support varargs and requires the
657 prototype of all callees to exactly match the prototype of the function
658 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]659 </dd>
660
661 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
662
663 <dd>This calling convention attempts to make code in the caller as efficient
664 as possible under the assumption that the call is not commonly executed. As
665 such, these calls often preserve all registers so that the call does not break
666 any live ranges in the caller side. This calling convention does not support
667 varargs and requires the prototype of all callees to exactly match the
668 prototype of the function definition.
669 </dd>
670
671 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
672
673 <dd>Any calling convention may be specified by number, allowing
674 target-specific calling conventions to be used. Target specific calling
675 conventions start at 64.
676 </dd>
677</dl>
678
679<p>More calling conventions can be added/defined on an as-needed basis, to
680support pascal conventions or any other well-known target-independent
681convention.</p>
682
683</div>
684
685<!-- ======================================================================= -->
686<div class="doc_subsection">
687 <a name="visibility">Visibility Styles</a>
688</div>
689
690<div class="doc_text">
691
692<p>
693All Global Variables and Functions have one of the following visibility styles:
694</p>
695
696<dl>
697 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
698
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]699 <dd>On targets that use the ELF object file format, default visibility means
700 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]701 modules and, in shared libraries, means that the declared entity may be
702 overridden. On Darwin, default visibility means that the declaration is
703 visible to other modules. Default visibility corresponds to "external
704 linkage" in the language.
705 </dd>
706
707 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
708
709 <dd>Two declarations of an object with hidden visibility refer to the same
710 object if they are in the same shared object. Usually, hidden visibility
711 indicates that the symbol will not be placed into the dynamic symbol table,
712 so no other module (executable or shared library) can reference it
713 directly.
714 </dd>
715
716 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
717
718 <dd>On ELF, protected visibility indicates that the symbol will be placed in
719 the dynamic symbol table, but that references within the defining module will
720 bind to the local symbol. That is, the symbol cannot be overridden by another
721 module.
722 </dd>
723</dl>
724
725</div>
726
727<!-- ======================================================================= -->
728<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]729 <a name="namedtypes">Named Types</a>
730</div>
731
732<div class="doc_text">
733
734<p>LLVM IR allows you to specify name aliases for certain types. This can make
735it easier to read the IR and make the IR more condensed (particularly when
736recursive types are involved). An example of a name specification is:
737</p>
738
739<div class="doc_code">
740<pre>
741%mytype = type { %mytype*, i32 }
742</pre>
743</div>
744
745<p>You may give a name to any <a href="#typesystem">type</a> except "<a
746href="t_void">void</a>". Type name aliases may be used anywhere a type is
747expected with the syntax "%mytype".</p>
748
749<p>Note that type names are aliases for the structural type that they indicate,
750and that you can therefore specify multiple names for the same type. This often
751leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
752structural typing, the name is not part of the type. When printing out LLVM IR,
753the printer will pick <em>one name</em> to render all types of a particular
754shape. This means that if you have code where two different source types end up
755having the same LLVM type, that the dumper will sometimes print the "wrong" or
756unexpected type. This is an important design point and isn't going to
757change.</p>
758
759</div>
760
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]761<!-- ======================================================================= -->
762<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]763 <a name="globalvars">Global Variables</a>
764</div>
765
766<div class="doc_text">
767
768<p>Global variables define regions of memory allocated at compilation time
769instead of run-time. Global variables may optionally be initialized, may have
770an explicit section to be placed in, and may have an optional explicit alignment
771specified. A variable may be defined as "thread_local", which means that it
772will not be shared by threads (each thread will have a separated copy of the
773variable). A variable may be defined as a global "constant," which indicates
774that the contents of the variable will <b>never</b> be modified (enabling better
775optimization, allowing the global data to be placed in the read-only section of
776an executable, etc). Note that variables that need runtime initialization
777cannot be marked "constant" as there is a store to the variable.</p>
778
779<p>
780LLVM explicitly allows <em>declarations</em> of global variables to be marked
781constant, even if the final definition of the global is not. This capability
782can be used to enable slightly better optimization of the program, but requires
783the language definition to guarantee that optimizations based on the
784'constantness' are valid for the translation units that do not include the
785definition.
786</p>
787
788<p>As SSA values, global variables define pointer values that are in
789scope (i.e. they dominate) all basic blocks in the program. Global
790variables always define a pointer to their "content" type because they
791describe a region of memory, and all memory objects in LLVM are
792accessed through pointers.</p>
793
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]794<p>A global variable may be declared to reside in a target-specifc numbered
795address space. For targets that support them, address spaces may affect how
796optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]797the variable. The default address space is zero. The address space qualifier
798must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]800<p>LLVM allows an explicit section to be specified for globals. If the target
801supports it, it will emit globals to the section specified.</p>
802
803<p>An explicit alignment may be specified for a global. If not present, or if
804the alignment is set to zero, the alignment of the global is set by the target
805to whatever it feels convenient. If an explicit alignment is specified, the
806global is forced to have at least that much alignment. All alignments must be
807a power of 2.</p>
808
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]809<p>For example, the following defines a global in a numbered address space with
810an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]811
812<div class="doc_code">
813<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]814@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]815</pre>
816</div>
817
818</div>
819
820
821<!-- ======================================================================= -->
822<div class="doc_subsection">
823 <a name="functionstructure">Functions</a>
824</div>
825
826<div class="doc_text">
827
828<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
829an optional <a href="#linkage">linkage type</a>, an optional
830<a href="#visibility">visibility style</a>, an optional
831<a href="#callingconv">calling convention</a>, a return type, an optional
832<a href="#paramattrs">parameter attribute</a> for the return type, a function
833name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]834<a href="#paramattrs">parameter attributes</a>), optional
835<a href="#fnattrs">function attributes</a>, an optional section,
836an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]837an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]838
839LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
840optional <a href="#linkage">linkage type</a>, an optional
841<a href="#visibility">visibility style</a>, an optional
842<a href="#callingconv">calling convention</a>, a return type, an optional
843<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]844name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]845<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]846
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]847<p>A function definition contains a list of basic blocks, forming the CFG
848(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]849the function. Each basic block may optionally start with a label (giving the
850basic block a symbol table entry), contains a list of instructions, and ends
851with a <a href="#terminators">terminator</a> instruction (such as a branch or
852function return).</p>
853
854<p>The first basic block in a function is special in two ways: it is immediately
855executed on entrance to the function, and it is not allowed to have predecessor
856basic blocks (i.e. there can not be any branches to the entry block of a
857function). Because the block can have no predecessors, it also cannot have any
858<a href="#i_phi">PHI nodes</a>.</p>
859
860<p>LLVM allows an explicit section to be specified for functions. If the target
861supports it, it will emit functions to the section specified.</p>
862
863<p>An explicit alignment may be specified for a function. If not present, or if
864the alignment is set to zero, the alignment of the function is set by the target
865to whatever it feels convenient. If an explicit alignment is specified, the
866function is forced to have at least that much alignment. All alignments must be
867a power of 2.</p>
868
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]869 <h5>Syntax:</h5>
870
871<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]872<tt>
873define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
874 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
875 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
876 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
877 [<a href="#gc">gc</a>] { ... }
878</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]879</div>
880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]881</div>
882
883
884<!-- ======================================================================= -->
885<div class="doc_subsection">
886 <a name="aliasstructure">Aliases</a>
887</div>
888<div class="doc_text">
889 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]890 function, global variable, another alias or bitcast of global value). Aliases
891 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892 optional <a href="#visibility">visibility style</a>.</p>
893
894 <h5>Syntax:</h5>
895
896<div class="doc_code">
897<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]898@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]899</pre>
900</div>
901
902</div>
903
904
905
906<!-- ======================================================================= -->
907<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
908<div class="doc_text">
909 <p>The return type and each parameter of a function type may have a set of
910 <i>parameter attributes</i> associated with them. Parameter attributes are
911 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]912 a function. Parameter attributes are considered to be part of the function,
913 not of the function type, so functions with different parameter attributes
914 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]915
916 <p>Parameter attributes are simple keywords that follow the type specified. If
917 multiple parameter attributes are needed, they are space separated. For
918 example:</p>
919
920<div class="doc_code">
921<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]922declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]923declare i32 @atoi(i8 zeroext)
924declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]925</pre>
926</div>
927
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]928 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
929 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]930
931 <p>Currently, only the following parameter attributes are defined:</p>
932 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]933 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]934 <dd>This indicates to the code generator that the parameter or return value
935 should be zero-extended to a 32-bit value by the caller (for a parameter)
936 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]937
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]938 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]939 <dd>This indicates to the code generator that the parameter or return value
940 should be sign-extended to a 32-bit value by the caller (for a parameter)
941 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]942
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]943 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]944 <dd>This indicates that this parameter or return value should be treated
945 in a special target-dependent fashion during while emitting code for a
946 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]947 to memory, though some targets use it to distinguish between two different
948 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]949
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]950 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]951 <dd>This indicates that the pointer parameter should really be passed by
952 value to the function. The attribute implies that a hidden copy of the
953 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]954 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]955 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]956 value, but is also valid on pointers to scalars. The copy is considered to
957 belong to the caller not the callee (for example,
958 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]959 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]960 values. The byval attribute also supports specifying an alignment with the
961 align attribute. This has a target-specific effect on the code generator
962 that usually indicates a desired alignment for the synthesized stack
963 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]965 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]966 <dd>This indicates that the pointer parameter specifies the address of a
967 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]968 This pointer must be guaranteed by the caller to be valid: loads and stores
969 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]970 be applied to the first parameter. This is not a valid attribute for
971 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]973 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]974 <dd>This indicates that the pointer does not alias any global or any other
975 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]976 case. On a function return value, <tt>noalias</tt> additionally indicates
977 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]978 caller. For further details, please see the discussion of the NoAlias
979 response in
980 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
981 analysis</a>.</dd>
982
983 <dt><tt>nocapture</tt></dt>
984 <dd>This indicates that the callee does not make any copies of the pointer
985 that outlive the callee itself. This is not a valid attribute for return
986 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]987
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]988 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]989 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]990 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
991 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]992 </dl>
993
994</div>
995
996<!-- ======================================================================= -->
997<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]998 <a name="gc">Garbage Collector Names</a>
999</div>
1000
1001<div class="doc_text">
1002<p>Each function may specify a garbage collector name, which is simply a
1003string.</p>
1004
1005<div class="doc_code"><pre
1006>define void @f() gc "name" { ...</pre></div>
1007
1008<p>The compiler declares the supported values of <i>name</i>. Specifying a
1009collector which will cause the compiler to alter its output in order to support
1010the named garbage collection algorithm.</p>
1011</div>
1012
1013<!-- ======================================================================= -->
1014<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1015 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1016</div>
1017
1018<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1019
1020<p>Function attributes are set to communicate additional information about
1021 a function. Function attributes are considered to be part of the function,
1022 not of the function type, so functions with different parameter attributes
1023 can have the same function type.</p>
1024
1025 <p>Function attributes are simple keywords that follow the type specified. If
1026 multiple attributes are needed, they are space separated. For
1027 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1028
1029<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1030<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1031define void @f() noinline { ... }
1032define void @f() alwaysinline { ... }
1033define void @f() alwaysinline optsize { ... }
1034define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1035</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1036</div>
1037
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1038<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1039<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1040<dd>This attribute indicates that the inliner should attempt to inline this
1041function into callers whenever possible, ignoring any active inlining size
1042threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1043
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1044<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1045<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1046in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1047<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1048
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1049<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1050<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1051make choices that keep the code size of this function low, and otherwise do
1052optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1053
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1054<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1055<dd>This function attribute indicates that the function never returns normally.
1056This produces undefined behavior at runtime if the function ever does
1057dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1058
1059<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1060<dd>This function attribute indicates that the function never returns with an
1061unwind or exceptional control flow. If the function does unwind, its runtime
1062behavior is undefined.</dd>
1063
1064<dt><tt>readnone</tt></dt>
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1065<dd>This attribute indicates that the function computes its result (or decides to
1066unwind an exception) based strictly on its arguments, without dereferencing any
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1067pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1068registers, etc) visible to caller functions. It does not write through any
1069pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1070never changes any state visible to callers. This means that it cannot unwind
1071exceptions by calling the <tt>C++</tt> exception throwing methods, but could
1072use the <tt>unwind</tt> instruction.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1073
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1074<dt><tt><a name="readonly">readonly</a></tt></dt>
1075<dd>This attribute indicates that the function does not write through any
1076pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1077or otherwise modify any state (e.g. memory, control registers, etc) visible to
1078caller functions. It may dereference pointer arguments and read state that may
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1079be set in the caller. A readonly function always returns the same value (or
1080unwinds an exception identically) when called with the same set of arguments
1081and global state. It cannot unwind an exception by calling the <tt>C++</tt>
1082exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1083
1084<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1085<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1086protector. It is in the form of a "canary"&mdash;a random value placed on the
1087stack before the local variables that's checked upon return from the function to
1088see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1089needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1090
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1091<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1092that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1093have an <tt>ssp</tt> attribute.</p></dd>
1094
1095<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1096<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1097stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1098function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1099
1100<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1101function that doesn't have an <tt>sspreq</tt> attribute or which has
1102an <tt>ssp</tt> attribute, then the resulting function will have
1103an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1104</dl>
1105
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1106</div>
1107
1108<!-- ======================================================================= -->
1109<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1110 <a name="moduleasm">Module-Level Inline Assembly</a>
1111</div>
1112
1113<div class="doc_text">
1114<p>
1115Modules may contain "module-level inline asm" blocks, which corresponds to the
1116GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1117LLVM and treated as a single unit, but may be separated in the .ll file if
1118desired. The syntax is very simple:
1119</p>
1120
1121<div class="doc_code">
1122<pre>
1123module asm "inline asm code goes here"
1124module asm "more can go here"
1125</pre>
1126</div>
1127
1128<p>The strings can contain any character by escaping non-printable characters.
1129 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1130 for the number.
1131</p>
1132
1133<p>
1134 The inline asm code is simply printed to the machine code .s file when
1135 assembly code is generated.
1136</p>
1137</div>
1138
1139<!-- ======================================================================= -->
1140<div class="doc_subsection">
1141 <a name="datalayout">Data Layout</a>
1142</div>
1143
1144<div class="doc_text">
1145<p>A module may specify a target specific data layout string that specifies how
1146data is to be laid out in memory. The syntax for the data layout is simply:</p>
1147<pre> target datalayout = "<i>layout specification</i>"</pre>
1148<p>The <i>layout specification</i> consists of a list of specifications
1149separated by the minus sign character ('-'). Each specification starts with a
1150letter and may include other information after the letter to define some
1151aspect of the data layout. The specifications accepted are as follows: </p>
1152<dl>
1153 <dt><tt>E</tt></dt>
1154 <dd>Specifies that the target lays out data in big-endian form. That is, the
1155 bits with the most significance have the lowest address location.</dd>
1156 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1157 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158 the bits with the least significance have the lowest address location.</dd>
1159 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1160 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1161 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1162 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1163 too.</dd>
1164 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1165 <dd>This specifies the alignment for an integer type of a given bit
1166 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1167 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1168 <dd>This specifies the alignment for a vector type of a given bit
1169 <i>size</i>.</dd>
1170 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1171 <dd>This specifies the alignment for a floating point type of a given bit
1172 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1173 (double).</dd>
1174 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1175 <dd>This specifies the alignment for an aggregate type of a given bit
1176 <i>size</i>.</dd>
1177</dl>
1178<p>When constructing the data layout for a given target, LLVM starts with a
1179default set of specifications which are then (possibly) overriden by the
1180specifications in the <tt>datalayout</tt> keyword. The default specifications
1181are given in this list:</p>
1182<ul>
1183 <li><tt>E</tt> - big endian</li>
1184 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1185 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1186 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1187 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1188 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1189 <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]1190 alignment of 64-bits</li>
1191 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1192 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1193 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1194 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1195 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1196</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1197<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1198following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1199<ol>
1200 <li>If the type sought is an exact match for one of the specifications, that
1201 specification is used.</li>
1202 <li>If no match is found, and the type sought is an integer type, then the
1203 smallest integer type that is larger than the bitwidth of the sought type is
1204 used. If none of the specifications are larger than the bitwidth then the the
1205 largest integer type is used. For example, given the default specifications
1206 above, the i7 type will use the alignment of i8 (next largest) while both
1207 i65 and i256 will use the alignment of i64 (largest specified).</li>
1208 <li>If no match is found, and the type sought is a vector type, then the
1209 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1210 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1211 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1212</ol>
1213</div>
1214
1215<!-- *********************************************************************** -->
1216<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1217<!-- *********************************************************************** -->
1218
1219<div class="doc_text">
1220
1221<p>The LLVM type system is one of the most important features of the
1222intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1223optimizations to be performed on the intermediate representation directly,
1224without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1225extra analyses on the side before the transformation. A strong type
1226system makes it easier to read the generated code and enables novel
1227analyses and transformations that are not feasible to perform on normal
1228three address code representations.</p>
1229
1230</div>
1231
1232<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1233<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1234Classifications</a> </div>
1235<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1236<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1237classifications:</p>
1238
1239<table border="1" cellspacing="0" cellpadding="4">
1240 <tbody>
1241 <tr><th>Classification</th><th>Types</th></tr>
1242 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1243 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1244 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1245 </tr>
1246 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1247 <td><a href="#t_floating">floating point</a></td>
1248 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1249 </tr>
1250 <tr>
1251 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1252 <td><a href="#t_integer">integer</a>,
1253 <a href="#t_floating">floating point</a>,
1254 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1255 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1256 <a href="#t_struct">structure</a>,
1257 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1258 <a href="#t_label">label</a>,
1259 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1260 </td>
1261 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1262 <tr>
1263 <td><a href="#t_primitive">primitive</a></td>
1264 <td><a href="#t_label">label</a>,
1265 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1266 <a href="#t_floating">floating point</a>,
1267 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1268 </tr>
1269 <tr>
1270 <td><a href="#t_derived">derived</a></td>
1271 <td><a href="#t_integer">integer</a>,
1272 <a href="#t_array">array</a>,
1273 <a href="#t_function">function</a>,
1274 <a href="#t_pointer">pointer</a>,
1275 <a href="#t_struct">structure</a>,
1276 <a href="#t_pstruct">packed structure</a>,
1277 <a href="#t_vector">vector</a>,
1278 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1279 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1280 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1281 </tbody>
1282</table>
1283
1284<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1285most important. Values of these types are the only ones which can be
1286produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1287instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1288</div>
1289
1290<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1291<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1292
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1293<div class="doc_text">
1294<p>The primitive types are the fundamental building blocks of the LLVM
1295system.</p>
1296
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1297</div>
1298
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1299<!-- _______________________________________________________________________ -->
1300<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1301
1302<div class="doc_text">
1303 <table>
1304 <tbody>
1305 <tr><th>Type</th><th>Description</th></tr>
1306 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1307 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1308 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1309 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1310 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1311 </tbody>
1312 </table>
1313</div>
1314
1315<!-- _______________________________________________________________________ -->
1316<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1317
1318<div class="doc_text">
1319<h5>Overview:</h5>
1320<p>The void type does not represent any value and has no size.</p>
1321
1322<h5>Syntax:</h5>
1323
1324<pre>
1325 void
1326</pre>
1327</div>
1328
1329<!-- _______________________________________________________________________ -->
1330<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1331
1332<div class="doc_text">
1333<h5>Overview:</h5>
1334<p>The label type represents code labels.</p>
1335
1336<h5>Syntax:</h5>
1337
1338<pre>
1339 label
1340</pre>
1341</div>
1342
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1343<!-- _______________________________________________________________________ -->
1344<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1345
1346<div class="doc_text">
1347<h5>Overview:</h5>
1348<p>The metadata type represents embedded metadata. The only derived type that
1349may contain metadata is <tt>metadata*</tt> or a function type that returns or
1350takes metadata typed parameters, but not pointer to metadata types.</p>
1351
1352<h5>Syntax:</h5>
1353
1354<pre>
1355 metadata
1356</pre>
1357</div>
1358
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1359
1360<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1361<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1362
1363<div class="doc_text">
1364
1365<p>The real power in LLVM comes from the derived types in the system.
1366This is what allows a programmer to represent arrays, functions,
1367pointers, and other useful types. Note that these derived types may be
1368recursive: For example, it is possible to have a two dimensional array.</p>
1369
1370</div>
1371
1372<!-- _______________________________________________________________________ -->
1373<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1374
1375<div class="doc_text">
1376
1377<h5>Overview:</h5>
1378<p>The integer type is a very simple derived type that simply specifies an
1379arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13802^23-1 (about 8 million) can be specified.</p>
1381
1382<h5>Syntax:</h5>
1383
1384<pre>
1385 iN
1386</pre>
1387
1388<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1389value.</p>
1390
1391<h5>Examples:</h5>
1392<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1393 <tr class="layout">
1394 <td class="left"><tt>i1</tt></td>
1395 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1396 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1397 <tr class="layout">
1398 <td class="left"><tt>i32</tt></td>
1399 <td class="left">a 32-bit integer.</td>
1400 </tr>
1401 <tr class="layout">
1402 <td class="left"><tt>i1942652</tt></td>
1403 <td class="left">a really big integer of over 1 million bits.</td>
1404 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1405</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1406
1407<p>Note that the code generator does not yet support large integer types
1408to be used as function return types. The specific limit on how large a
1409return type the code generator can currently handle is target-dependent;
1410currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1411targets.</p>
1412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1413</div>
1414
1415<!-- _______________________________________________________________________ -->
1416<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1417
1418<div class="doc_text">
1419
1420<h5>Overview:</h5>
1421
1422<p>The array type is a very simple derived type that arranges elements
1423sequentially in memory. The array type requires a size (number of
1424elements) and an underlying data type.</p>
1425
1426<h5>Syntax:</h5>
1427
1428<pre>
1429 [&lt;# elements&gt; x &lt;elementtype&gt;]
1430</pre>
1431
1432<p>The number of elements is a constant integer value; elementtype may
1433be any type with a size.</p>
1434
1435<h5>Examples:</h5>
1436<table class="layout">
1437 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1438 <td class="left"><tt>[40 x i32]</tt></td>
1439 <td class="left">Array of 40 32-bit integer values.</td>
1440 </tr>
1441 <tr class="layout">
1442 <td class="left"><tt>[41 x i32]</tt></td>
1443 <td class="left">Array of 41 32-bit integer values.</td>
1444 </tr>
1445 <tr class="layout">
1446 <td class="left"><tt>[4 x i8]</tt></td>
1447 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1448 </tr>
1449</table>
1450<p>Here are some examples of multidimensional arrays:</p>
1451<table class="layout">
1452 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1453 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1454 <td class="left">3x4 array of 32-bit integer values.</td>
1455 </tr>
1456 <tr class="layout">
1457 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1458 <td class="left">12x10 array of single precision floating point values.</td>
1459 </tr>
1460 <tr class="layout">
1461 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1462 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1463 </tr>
1464</table>
1465
1466<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1467length array. Normally, accesses past the end of an array are undefined in
1468LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1469As a special case, however, zero length arrays are recognized to be variable
1470length. This allows implementation of 'pascal style arrays' with the LLVM
1471type "{ i32, [0 x float]}", for example.</p>
1472
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1473<p>Note that the code generator does not yet support large aggregate types
1474to be used as function return types. The specific limit on how large an
1475aggregate return type the code generator can currently handle is
1476target-dependent, and also dependent on the aggregate element types.</p>
1477
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1478</div>
1479
1480<!-- _______________________________________________________________________ -->
1481<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1482<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1484<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1486<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1487consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1488return 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]1489If 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]1490class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1492<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1493
1494<pre>
1495 &lt;returntype list&gt; (&lt;parameter list&gt;)
1496</pre>
1497
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1498<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1499specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1500which indicates that the function takes a variable number of arguments.
1501Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1502 href="#int_varargs">variable argument handling intrinsic</a> functions.
1503'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1504<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1505
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1506<h5>Examples:</h5>
1507<table class="layout">
1508 <tr class="layout">
1509 <td class="left"><tt>i32 (i32)</tt></td>
1510 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1511 </td>
1512 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1513 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1514 </tt></td>
1515 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1516 an <tt>i16</tt> that should be sign extended and a
1517 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1518 <tt>float</tt>.
1519 </td>
1520 </tr><tr class="layout">
1521 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1522 <td class="left">A vararg function that takes at least one
1523 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1524 which returns an integer. This is the signature for <tt>printf</tt> in
1525 LLVM.
1526 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1527 </tr><tr class="layout">
1528 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1529 <td class="left">A function taking an <tt>i32</tt>, returning two
1530 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1531 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1532 </tr>
1533</table>
1534
1535</div>
1536<!-- _______________________________________________________________________ -->
1537<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1538<div class="doc_text">
1539<h5>Overview:</h5>
1540<p>The structure type is used to represent a collection of data members
1541together in memory. The packing of the field types is defined to match
1542the ABI of the underlying processor. The elements of a structure may
1543be any type that has a size.</p>
1544<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1545and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1546field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1547instruction.</p>
1548<h5>Syntax:</h5>
1549<pre> { &lt;type list&gt; }<br></pre>
1550<h5>Examples:</h5>
1551<table class="layout">
1552 <tr class="layout">
1553 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1554 <td class="left">A triple of three <tt>i32</tt> values</td>
1555 </tr><tr class="layout">
1556 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1557 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1558 second element is a <a href="#t_pointer">pointer</a> to a
1559 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1560 an <tt>i32</tt>.</td>
1561 </tr>
1562</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1563
1564<p>Note that the code generator does not yet support large aggregate types
1565to be used as function return types. The specific limit on how large an
1566aggregate return type the code generator can currently handle is
1567target-dependent, and also dependent on the aggregate element types.</p>
1568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1569</div>
1570
1571<!-- _______________________________________________________________________ -->
1572<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1573</div>
1574<div class="doc_text">
1575<h5>Overview:</h5>
1576<p>The packed structure type is used to represent a collection of data members
1577together in memory. There is no padding between fields. Further, the alignment
1578of a packed structure is 1 byte. The elements of a packed structure may
1579be any type that has a size.</p>
1580<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1581and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1582field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1583instruction.</p>
1584<h5>Syntax:</h5>
1585<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1586<h5>Examples:</h5>
1587<table class="layout">
1588 <tr class="layout">
1589 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1590 <td class="left">A triple of three <tt>i32</tt> values</td>
1591 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1592 <td class="left">
1593<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1594 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1595 second element is a <a href="#t_pointer">pointer</a> to a
1596 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1597 an <tt>i32</tt>.</td>
1598 </tr>
1599</table>
1600</div>
1601
1602<!-- _______________________________________________________________________ -->
1603<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1604<div class="doc_text">
1605<h5>Overview:</h5>
1606<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1607reference to another object, which must live in memory. Pointer types may have
1608an optional address space attribute defining the target-specific numbered
1609address space where the pointed-to object resides. The default address space is
1610zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1611
1612<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]1613it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1615<h5>Syntax:</h5>
1616<pre> &lt;type&gt; *<br></pre>
1617<h5>Examples:</h5>
1618<table class="layout">
1619 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1620 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1621 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1622 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1623 </tr>
1624 <tr class="layout">
1625 <td class="left"><tt>i32 (i32 *) *</tt></td>
1626 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1627 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1628 <tt>i32</tt>.</td>
1629 </tr>
1630 <tr class="layout">
1631 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1632 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1633 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1634 </tr>
1635</table>
1636</div>
1637
1638<!-- _______________________________________________________________________ -->
1639<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1640<div class="doc_text">
1641
1642<h5>Overview:</h5>
1643
1644<p>A vector type is a simple derived type that represents a vector
1645of elements. Vector types are used when multiple primitive data
1646are operated in parallel using a single instruction (SIMD).
1647A vector type requires a size (number of
1648elements) and an underlying primitive data type. Vectors must have a power
1649of two length (1, 2, 4, 8, 16 ...). Vector types are
1650considered <a href="#t_firstclass">first class</a>.</p>
1651
1652<h5>Syntax:</h5>
1653
1654<pre>
1655 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1656</pre>
1657
1658<p>The number of elements is a constant integer value; elementtype may
1659be any integer or floating point type.</p>
1660
1661<h5>Examples:</h5>
1662
1663<table class="layout">
1664 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1665 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1666 <td class="left">Vector of 4 32-bit integer values.</td>
1667 </tr>
1668 <tr class="layout">
1669 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1670 <td class="left">Vector of 8 32-bit floating-point values.</td>
1671 </tr>
1672 <tr class="layout">
1673 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1674 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1675 </tr>
1676</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1677
1678<p>Note that the code generator does not yet support large vector types
1679to be used as function return types. The specific limit on how large a
1680vector return type codegen can currently handle is target-dependent;
1681currently it's often a few times longer than a hardware vector register.</p>
1682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1683</div>
1684
1685<!-- _______________________________________________________________________ -->
1686<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1687<div class="doc_text">
1688
1689<h5>Overview:</h5>
1690
1691<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1692corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1693In LLVM, opaque types can eventually be resolved to any type (not just a
1694structure type).</p>
1695
1696<h5>Syntax:</h5>
1697
1698<pre>
1699 opaque
1700</pre>
1701
1702<h5>Examples:</h5>
1703
1704<table class="layout">
1705 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1706 <td class="left"><tt>opaque</tt></td>
1707 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1708 </tr>
1709</table>
1710</div>
1711
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1712<!-- ======================================================================= -->
1713<div class="doc_subsection">
1714 <a name="t_uprefs">Type Up-references</a>
1715</div>
1716
1717<div class="doc_text">
1718<h5>Overview:</h5>
1719<p>
1720An "up reference" allows you to refer to a lexically enclosing type without
1721requiring it to have a name. For instance, a structure declaration may contain a
1722pointer to any of the types it is lexically a member of. Example of up
1723references (with their equivalent as named type declarations) include:</p>
1724
1725<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1726 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1727 { \2 }* %y = type { %y }*
1728 \1* %z = type %z*
1729</pre>
1730
1731<p>
1732An up reference is needed by the asmprinter for printing out cyclic types when
1733there is no declared name for a type in the cycle. Because the asmprinter does
1734not want to print out an infinite type string, it needs a syntax to handle
1735recursive types that have no names (all names are optional in llvm IR).
1736</p>
1737
1738<h5>Syntax:</h5>
1739<pre>
1740 \&lt;level&gt;
1741</pre>
1742
1743<p>
1744The level is the count of the lexical type that is being referred to.
1745</p>
1746
1747<h5>Examples:</h5>
1748
1749<table class="layout">
1750 <tr class="layout">
1751 <td class="left"><tt>\1*</tt></td>
1752 <td class="left">Self-referential pointer.</td>
1753 </tr>
1754 <tr class="layout">
1755 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1756 <td class="left">Recursive structure where the upref refers to the out-most
1757 structure.</td>
1758 </tr>
1759</table>
1760</div>
1761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1762
1763<!-- *********************************************************************** -->
1764<div class="doc_section"> <a name="constants">Constants</a> </div>
1765<!-- *********************************************************************** -->
1766
1767<div class="doc_text">
1768
1769<p>LLVM has several different basic types of constants. This section describes
1770them all and their syntax.</p>
1771
1772</div>
1773
1774<!-- ======================================================================= -->
1775<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1776
1777<div class="doc_text">
1778
1779<dl>
1780 <dt><b>Boolean constants</b></dt>
1781
1782 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1783 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1784 </dd>
1785
1786 <dt><b>Integer constants</b></dt>
1787
1788 <dd>Standard integers (such as '4') are constants of the <a
1789 href="#t_integer">integer</a> type. Negative numbers may be used with
1790 integer types.
1791 </dd>
1792
1793 <dt><b>Floating point constants</b></dt>
1794
1795 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1796 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1797 notation (see below). The assembler requires the exact decimal value of
1798 a floating-point constant. For example, the assembler accepts 1.25 but
1799 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1800 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1801
1802 <dt><b>Null pointer constants</b></dt>
1803
1804 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1805 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1806
1807</dl>
1808
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1809<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1810of floating point constants. For example, the form '<tt>double
18110x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
18124.5e+15</tt>'. The only time hexadecimal floating point constants are required
1813(and the only time that they are generated by the disassembler) is when a
1814floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1815decimal floating point number in a reasonable number of digits. For example,
1816NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817special values are represented in their IEEE hexadecimal format so that
1818assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1819<p>When using the hexadecimal form, constants of types float and double are
1820represented using the 16-digit form shown above (which matches the IEEE754
1821representation for double); float values must, however, be exactly representable
1822as IEE754 single precision.
1823Hexadecimal format is always used for long
1824double, and there are three forms of long double. The 80-bit
1825format used by x86 is represented as <tt>0xK</tt>
1826followed by 20 hexadecimal digits.
1827The 128-bit format used by PowerPC (two adjacent doubles) is represented
1828by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1829format is represented
1830by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1831target uses this format. Long doubles will only work if they match
1832the long double format on your target. All hexadecimal formats are big-endian
1833(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1834</div>
1835
1836<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1837<div class="doc_subsection">
1838<a name="aggregateconstants"> <!-- old anchor -->
1839<a name="complexconstants">Complex Constants</a></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1840</div>
1841
1842<div class="doc_text">
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1843<p>Complex constants are a (potentially recursive) combination of simple
1844constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1845
1846<dl>
1847 <dt><b>Structure constants</b></dt>
1848
1849 <dd>Structure constants are represented with notation similar to structure
1850 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1851 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1852 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]1853 must have <a href="#t_struct">structure type</a>, and the number and
1854 types of elements must match those specified by the type.
1855 </dd>
1856
1857 <dt><b>Array constants</b></dt>
1858
1859 <dd>Array constants are represented with notation similar to array type
1860 definitions (a comma separated list of elements, surrounded by square brackets
1861 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1862 constants must have <a href="#t_array">array type</a>, and the number and
1863 types of elements must match those specified by the type.
1864 </dd>
1865
1866 <dt><b>Vector constants</b></dt>
1867
1868 <dd>Vector constants are represented with notation similar to vector type
1869 definitions (a comma separated list of elements, surrounded by
1870 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1871 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1872 href="#t_vector">vector type</a>, and the number and types of elements must
1873 match those specified by the type.
1874 </dd>
1875
1876 <dt><b>Zero initialization</b></dt>
1877
1878 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1879 value to zero of <em>any</em> type, including scalar and aggregate types.
1880 This is often used to avoid having to print large zero initializers (e.g. for
1881 large arrays) and is always exactly equivalent to using explicit zero
1882 initializers.
1883 </dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1884
1885 <dt><b>Metadata node</b></dt>
1886
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1887 <dd>A metadata node is a structure-like constant with
1888 <a href="#t_metadata">metadata type</a>. For example:
1889 "<tt>metadata !{ i32 0, metadata !"test" }</tt>". Unlike other constants
1890 that are meant to be interpreted as part of the instruction stream, metadata
1891 is a place to attach additional information such as debug info.
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1892 </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1893</dl>
1894
1895</div>
1896
1897<!-- ======================================================================= -->
1898<div class="doc_subsection">
1899 <a name="globalconstants">Global Variable and Function Addresses</a>
1900</div>
1901
1902<div class="doc_text">
1903
1904<p>The addresses of <a href="#globalvars">global variables</a> and <a
1905href="#functionstructure">functions</a> are always implicitly valid (link-time)
1906constants. These constants are explicitly referenced when the <a
1907href="#identifiers">identifier for the global</a> is used and always have <a
1908href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1909file:</p>
1910
1911<div class="doc_code">
1912<pre>
1913@X = global i32 17
1914@Y = global i32 42
1915@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1916</pre>
1917</div>
1918
1919</div>
1920
1921<!-- ======================================================================= -->
1922<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1923<div class="doc_text">
1924 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1925 no specific value. Undefined values may be of any type and be used anywhere
1926 a constant is permitted.</p>
1927
1928 <p>Undefined values indicate to the compiler that the program is well defined
1929 no matter what value is used, giving the compiler more freedom to optimize.
1930 </p>
1931</div>
1932
1933<!-- ======================================================================= -->
1934<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1935</div>
1936
1937<div class="doc_text">
1938
1939<p>Constant expressions are used to allow expressions involving other constants
1940to be used as constants. Constant expressions may be of any <a
1941href="#t_firstclass">first class</a> type and may involve any LLVM operation
1942that does not have side effects (e.g. load and call are not supported). The
1943following is the syntax for constant expressions:</p>
1944
1945<dl>
1946 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1947 <dd>Truncate a constant to another type. The bit size of CST must be larger
1948 than the bit size of TYPE. Both types must be integers.</dd>
1949
1950 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1951 <dd>Zero extend a constant to another type. The bit size of CST must be
1952 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1953
1954 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1955 <dd>Sign extend a constant to another type. The bit size of CST must be
1956 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1957
1958 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1959 <dd>Truncate a floating point constant to another floating point type. The
1960 size of CST must be larger than the size of TYPE. Both types must be
1961 floating point.</dd>
1962
1963 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1964 <dd>Floating point extend a constant to another type. The size of CST must be
1965 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1966
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1967 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1968 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1969 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1970 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1971 of the same number of elements. If the value won't fit in the integer type,
1972 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1973
1974 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1975 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1976 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1977 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1978 of the same number of elements. If the value won't fit in the integer type,
1979 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1980
1981 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1982 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1983 constant. TYPE must be a scalar or vector floating point type. CST must be of
1984 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1985 of the same number of elements. If the value won't fit in the floating point
1986 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1987
1988 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1989 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1990 constant. TYPE must be a scalar or vector floating point type. CST must be of
1991 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1992 of the same number of elements. If the value won't fit in the floating point
1993 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1994
1995 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1996 <dd>Convert a pointer typed constant to the corresponding integer constant
1997 TYPE must be an integer type. CST must be of pointer type. The CST value is
1998 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1999
2000 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
2001 <dd>Convert a integer constant to a pointer constant. TYPE must be a
2002 pointer type. CST must be of integer type. The CST value is zero extended,
2003 truncated, or unchanged to make it fit in a pointer size. This one is
2004 <i>really</i> dangerous!</dd>
2005
2006 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2007 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2008 are the same as those for the <a href="#i_bitcast">bitcast
2009 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2010
2011 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
2012
2013 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
2014 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2015 instruction, the index list may have zero or more indexes, which are required
2016 to make sense for the type of "CSTPTR".</dd>
2017
2018 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
2019
2020 <dd>Perform the <a href="#i_select">select operation</a> on
2021 constants.</dd>
2022
2023 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2024 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2025
2026 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2027 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2028
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]2029 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
2030 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
2031
2032 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
2033 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
2034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2035 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2036
2037 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2038 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2039
2040 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2041
2042 <dd>Perform the <a href="#i_insertelement">insertelement
2043 operation</a> on constants.</dd>
2044
2045
2046 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2047
2048 <dd>Perform the <a href="#i_shufflevector">shufflevector
2049 operation</a> on constants.</dd>
2050
2051 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2052
2053 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2054 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2055 binary</a> operations. The constraints on operands are the same as those for
2056 the corresponding instruction (e.g. no bitwise operations on floating point
2057 values are allowed).</dd>
2058</dl>
2059</div>
2060
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2061<!-- ======================================================================= -->
2062<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2063</div>
2064
2065<div class="doc_text">
2066
2067<p>Embedded metadata provides a way to attach arbitrary data to the
2068instruction stream without affecting the behaviour of the program. There are
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2069two metadata primitives, strings and nodes. All metadata has the
2070<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2071point ('<tt>!</tt>').
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2072</p>
2073
2074<p>A metadata string is a string surrounded by double quotes. It can contain
2075any character by escaping non-printable characters with "\xx" where "xx" is
2076the two digit hex code. For example: "<tt>!"test\00"</tt>".
2077</p>
2078
2079<p>Metadata nodes are represented with notation similar to structure constants
2080(a comma separated list of elements, surrounded by braces and preceeded by an
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2081exclamation point). For example: "<tt>!{ metadata !"test\00", i32 10}</tt>".
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2082</p>
2083
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2084<p>A metadata node will attempt to track changes to the values it holds. In
2085the event that a value is deleted, it will be replaced with a typeless
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2086"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2087
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2088<p>Optimizations may rely on metadata to provide additional information about
2089the program that isn't available in the instructions, or that isn't easily
2090computable. Similarly, the code generator may expect a certain metadata format
2091to be used to express debugging information.</p>
2092</div>
2093
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2094<!-- *********************************************************************** -->
2095<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2096<!-- *********************************************************************** -->
2097
2098<!-- ======================================================================= -->
2099<div class="doc_subsection">
2100<a name="inlineasm">Inline Assembler Expressions</a>
2101</div>
2102
2103<div class="doc_text">
2104
2105<p>
2106LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2107Module-Level Inline Assembly</a>) through the use of a special value. This
2108value represents the inline assembler as a string (containing the instructions
2109to emit), a list of operand constraints (stored as a string), and a flag that
2110indicates whether or not the inline asm expression has side effects. An example
2111inline assembler expression is:
2112</p>
2113
2114<div class="doc_code">
2115<pre>
2116i32 (i32) asm "bswap $0", "=r,r"
2117</pre>
2118</div>
2119
2120<p>
2121Inline assembler expressions may <b>only</b> be used as the callee operand of
2122a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2123</p>
2124
2125<div class="doc_code">
2126<pre>
2127%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2128</pre>
2129</div>
2130
2131<p>
2132Inline asms with side effects not visible in the constraint list must be marked
2133as having side effects. This is done through the use of the
2134'<tt>sideeffect</tt>' keyword, like so:
2135</p>
2136
2137<div class="doc_code">
2138<pre>
2139call void asm sideeffect "eieio", ""()
2140</pre>
2141</div>
2142
2143<p>TODO: The format of the asm and constraints string still need to be
2144documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2145need to be documented). This is probably best done by reference to another
2146document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2147</p>
2148
2149</div>
2150
2151<!-- *********************************************************************** -->
2152<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2153<!-- *********************************************************************** -->
2154
2155<div class="doc_text">
2156
2157<p>The LLVM instruction set consists of several different
2158classifications of instructions: <a href="#terminators">terminator
2159instructions</a>, <a href="#binaryops">binary instructions</a>,
2160<a href="#bitwiseops">bitwise binary instructions</a>, <a
2161 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2162instructions</a>.</p>
2163
2164</div>
2165
2166<!-- ======================================================================= -->
2167<div class="doc_subsection"> <a name="terminators">Terminator
2168Instructions</a> </div>
2169
2170<div class="doc_text">
2171
2172<p>As mentioned <a href="#functionstructure">previously</a>, every
2173basic block in a program ends with a "Terminator" instruction, which
2174indicates which block should be executed after the current block is
2175finished. These terminator instructions typically yield a '<tt>void</tt>'
2176value: they produce control flow, not values (the one exception being
2177the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2178<p>There are six different terminator instructions: the '<a
2179 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2180instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2181the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2182 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2183 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2184
2185</div>
2186
2187<!-- _______________________________________________________________________ -->
2188<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2189Instruction</a> </div>
2190<div class="doc_text">
2191<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2192<pre>
2193 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]2194 ret void <i>; Return from void function</i>
2195</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2196
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2197<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2198
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2199<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2200optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2201<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2202returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2203control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2204
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2205<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2206
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2207<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2208the return value. The type of the return value must be a
2209'<a href="#t_firstclass">first class</a>' type.</p>
2210
2211<p>A function is not <a href="#wellformed">well formed</a> if
2212it it has a non-void return type and contains a '<tt>ret</tt>'
2213instruction with no return value or a return value with a type that
2214does not match its type, or if it has a void return type and contains
2215a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2217<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2218
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2219<p>When the '<tt>ret</tt>' instruction is executed, control flow
2220returns back to the calling function's context. If the caller is a "<a
2221 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2222the instruction after the call. If the caller was an "<a
2223 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2224at the beginning of the "normal" destination block. If the instruction
2225returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2226return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2228<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2229
2230<pre>
2231 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2232 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2233 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]2234</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2235
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2236<p>Note that the code generator does not yet fully support large
2237 return values. The specific sizes that are currently supported are
2238 dependent on the target. For integers, on 32-bit targets the limit
2239 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2240 For aggregate types, the current limits are dependent on the element
2241 types; for example targets are often limited to 2 total integer
2242 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2243
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2244</div>
2245<!-- _______________________________________________________________________ -->
2246<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2247<div class="doc_text">
2248<h5>Syntax:</h5>
2249<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2250</pre>
2251<h5>Overview:</h5>
2252<p>The '<tt>br</tt>' instruction is used to cause control flow to
2253transfer to a different basic block in the current function. There are
2254two forms of this instruction, corresponding to a conditional branch
2255and an unconditional branch.</p>
2256<h5>Arguments:</h5>
2257<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2258single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2259unconditional form of the '<tt>br</tt>' instruction takes a single
2260'<tt>label</tt>' value as a target.</p>
2261<h5>Semantics:</h5>
2262<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2263argument is evaluated. If the value is <tt>true</tt>, control flows
2264to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2265control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2266<h5>Example:</h5>
Chris Lattner95127832009-05-09 18:11:50 +0000[diff] [blame]2267<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]2268 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2269</div>
2270<!-- _______________________________________________________________________ -->
2271<div class="doc_subsubsection">
2272 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2273</div>
2274
2275<div class="doc_text">
2276<h5>Syntax:</h5>
2277
2278<pre>
2279 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2280</pre>
2281
2282<h5>Overview:</h5>
2283
2284<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2285several different places. It is a generalization of the '<tt>br</tt>'
2286instruction, allowing a branch to occur to one of many possible
2287destinations.</p>
2288
2289
2290<h5>Arguments:</h5>
2291
2292<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2293comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2294an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2295table is not allowed to contain duplicate constant entries.</p>
2296
2297<h5>Semantics:</h5>
2298
2299<p>The <tt>switch</tt> instruction specifies a table of values and
2300destinations. When the '<tt>switch</tt>' instruction is executed, this
2301table is searched for the given value. If the value is found, control flow is
2302transfered to the corresponding destination; otherwise, control flow is
2303transfered to the default destination.</p>
2304
2305<h5>Implementation:</h5>
2306
2307<p>Depending on properties of the target machine and the particular
2308<tt>switch</tt> instruction, this instruction may be code generated in different
2309ways. For example, it could be generated as a series of chained conditional
2310branches or with a lookup table.</p>
2311
2312<h5>Example:</h5>
2313
2314<pre>
2315 <i>; Emulate a conditional br instruction</i>
2316 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2317 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2318
2319 <i>; Emulate an unconditional br instruction</i>
2320 switch i32 0, label %dest [ ]
2321
2322 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2323 switch i32 %val, label %otherwise [ i32 0, label %onzero
2324 i32 1, label %onone
2325 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2326</pre>
2327</div>
2328
2329<!-- _______________________________________________________________________ -->
2330<div class="doc_subsubsection">
2331 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2332</div>
2333
2334<div class="doc_text">
2335
2336<h5>Syntax:</h5>
2337
2338<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2339 &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]2340 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2341</pre>
2342
2343<h5>Overview:</h5>
2344
2345<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2346function, with the possibility of control flow transfer to either the
2347'<tt>normal</tt>' label or the
2348'<tt>exception</tt>' label. If the callee function returns with the
2349"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2350"normal" label. If the callee (or any indirect callees) returns with the "<a
2351href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2352continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353
2354<h5>Arguments:</h5>
2355
2356<p>This instruction requires several arguments:</p>
2357
2358<ol>
2359 <li>
2360 The optional "cconv" marker indicates which <a href="#callingconv">calling
2361 convention</a> the call should use. If none is specified, the call defaults
2362 to using C calling conventions.
2363 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2364
2365 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2366 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2367 and '<tt>inreg</tt>' attributes are valid here.</li>
2368
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2369 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2370 function value being invoked. In most cases, this is a direct function
2371 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2372 an arbitrary pointer to function value.
2373 </li>
2374
2375 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2376 function to be invoked. </li>
2377
2378 <li>'<tt>function args</tt>': argument list whose types match the function
2379 signature argument types. If the function signature indicates the function
2380 accepts a variable number of arguments, the extra arguments can be
2381 specified. </li>
2382
2383 <li>'<tt>normal label</tt>': the label reached when the called function
2384 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2385
2386 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2387 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2388
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2389 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2390 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2391 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2392</ol>
2393
2394<h5>Semantics:</h5>
2395
2396<p>This instruction is designed to operate as a standard '<tt><a
2397href="#i_call">call</a></tt>' instruction in most regards. The primary
2398difference is that it establishes an association with a label, which is used by
2399the runtime library to unwind the stack.</p>
2400
2401<p>This instruction is used in languages with destructors to ensure that proper
2402cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2403exception. Additionally, this is important for implementation of
2404'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2405
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]2406<p>For the purposes of the SSA form, the definition of the value
2407returned by the '<tt>invoke</tt>' instruction is deemed to occur on
2408the edge from the current block to the "normal" label. If the callee
2409unwinds then no return value is available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2411<h5>Example:</h5>
2412<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2413 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2415 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2416 unwind label %TestCleanup <i>; {i32}:retval set</i>
2417</pre>
2418</div>
2419
2420
2421<!-- _______________________________________________________________________ -->
2422
2423<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2424Instruction</a> </div>
2425
2426<div class="doc_text">
2427
2428<h5>Syntax:</h5>
2429<pre>
2430 unwind
2431</pre>
2432
2433<h5>Overview:</h5>
2434
2435<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2436at the first callee in the dynamic call stack which used an <a
2437href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2438primarily used to implement exception handling.</p>
2439
2440<h5>Semantics:</h5>
2441
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2442<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2443immediately halt. The dynamic call stack is then searched for the first <a
2444href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2445execution continues at the "exceptional" destination block specified by the
2446<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2447dynamic call chain, undefined behavior results.</p>
2448</div>
2449
2450<!-- _______________________________________________________________________ -->
2451
2452<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2453Instruction</a> </div>
2454
2455<div class="doc_text">
2456
2457<h5>Syntax:</h5>
2458<pre>
2459 unreachable
2460</pre>
2461
2462<h5>Overview:</h5>
2463
2464<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2465instruction is used to inform the optimizer that a particular portion of the
2466code is not reachable. This can be used to indicate that the code after a
2467no-return function cannot be reached, and other facts.</p>
2468
2469<h5>Semantics:</h5>
2470
2471<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2472</div>
2473
2474
2475
2476<!-- ======================================================================= -->
2477<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2478<div class="doc_text">
2479<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2480program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2481produce a single value. The operands might represent
2482multiple 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]2483The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2484<p>There are several different binary operators:</p>
2485</div>
2486<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487<div class="doc_subsubsection">
2488 <a name="i_add">'<tt>add</tt>' Instruction</a>
2489</div>
2490
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2491<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2493<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2494
2495<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2496 &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]2497</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2504
2505<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2506 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2507 <a href="#t_vector">vector</a> values. Both arguments must have identical
2508 types.</p>
2509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2510<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2511
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512<p>The value produced is the integer or floating point sum of the two
2513operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2514
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2515<p>If an integer sum has unsigned overflow, the result returned is the
2516mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2517the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2518
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2519<p>Because LLVM integers use a two's complement representation, this
2520instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2521
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2522<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2523
2524<pre>
2525 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2526</pre>
2527</div>
2528<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2529<div class="doc_subsubsection">
2530 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2531</div>
2532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2533<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2536
2537<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2538 &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]2539</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2541<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543<p>The '<tt>sub</tt>' instruction returns the difference of its two
2544operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2545
2546<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2547'<tt>neg</tt>' instruction present in most other intermediate
2548representations.</p>
2549
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2551
2552<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2553 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2554 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2555 types.</p>
2556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2557<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2558
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559<p>The value produced is the integer or floating point difference of
2560the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2561
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2562<p>If an integer difference has unsigned overflow, the result returned is the
2563mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2564the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2565
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2566<p>Because LLVM integers use a two's complement representation, this
2567instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2569<h5>Example:</h5>
2570<pre>
2571 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2572 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2573</pre>
2574</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2577<div class="doc_subsubsection">
2578 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2579</div>
2580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2581<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2584<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]2585</pre>
2586<h5>Overview:</h5>
2587<p>The '<tt>mul</tt>' instruction returns the product of its two
2588operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2591
2592<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2593href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2594or <a href="#t_vector">vector</a> values. Both arguments must have identical
2595types.</p>
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 Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2599<p>The value produced is the integer or floating point product of the
2600two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2601
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2602<p>If the result of an integer multiplication has unsigned overflow,
2603the result returned is the mathematical result modulo
26042<sup>n</sup>, where n is the bit width of the result.</p>
2605<p>Because LLVM integers use a two's complement representation, and the
2606result is the same width as the operands, this instruction returns the
2607correct result for both signed and unsigned integers. If a full product
2608(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2609should be sign-extended or zero-extended as appropriate to the
2610width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2611<h5>Example:</h5>
2612<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2613</pre>
2614</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616<!-- _______________________________________________________________________ -->
2617<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2618</a></div>
2619<div class="doc_text">
2620<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2621<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]2622</pre>
2623<h5>Overview:</h5>
2624<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2625operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2626
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2630<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2631values. Both arguments must have identical types.</p>
2632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2634
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2635<p>The value produced is the unsigned integer quotient of the two operands.</p>
2636<p>Note that unsigned integer division and signed integer division are distinct
2637operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2638<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2639<h5>Example:</h5>
2640<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2641</pre>
2642</div>
2643<!-- _______________________________________________________________________ -->
2644<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2645</a> </div>
2646<div class="doc_text">
2647<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2648<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2649 &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]2650</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2651
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2652<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2655operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2656
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2657<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2658
2659<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2660<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2661values. Both arguments must have identical types.</p>
2662
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2663<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2664<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]2665<p>Note that signed integer division and unsigned integer division are distinct
2666operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2667<p>Division by zero leads to undefined behavior. Overflow also leads to
2668undefined behavior; this is a rare case, but can occur, for example,
2669by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670<h5>Example:</h5>
2671<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2672</pre>
2673</div>
2674<!-- _______________________________________________________________________ -->
2675<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2676Instruction</a> </div>
2677<div class="doc_text">
2678<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2679<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2680 &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]2681</pre>
2682<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2683
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2684<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2685operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2687<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2689<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2690<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2691of floating point values. Both arguments must have identical types.</p>
2692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2697<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2698
2699<pre>
2700 &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]2701</pre>
2702</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2703
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2704<!-- _______________________________________________________________________ -->
2705<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2706</div>
2707<div class="doc_text">
2708<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2709<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]2710</pre>
2711<h5>Overview:</h5>
2712<p>The '<tt>urem</tt>' instruction returns the remainder from the
2713unsigned division of its two arguments.</p>
2714<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2715<p>The two arguments to the '<tt>urem</tt>' instruction must be
2716<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2717values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2718<h5>Semantics:</h5>
2719<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2720This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2721<p>Note that unsigned integer remainder and signed integer remainder are
2722distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2723<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2724<h5>Example:</h5>
2725<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2726</pre>
2727
2728</div>
2729<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2730<div class="doc_subsubsection">
2731 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2732</div>
2733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2734<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2737
2738<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2739 &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]2740</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2742<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2745signed division of its two operands. This instruction can also take
2746<a href="#t_vector">vector</a> versions of the values in which case
2747the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2749<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2751<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2752<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2753values. Both arguments must have identical types.</p>
2754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2755<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2758has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2759operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2760a value. For more information about the difference, see <a
2761 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2762Math Forum</a>. For a table of how this is implemented in various languages,
2763please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2764Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2765<p>Note that signed integer remainder and unsigned integer remainder are
2766distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2767<p>Taking the remainder of a division by zero leads to undefined behavior.
2768Overflow also leads to undefined behavior; this is a rare case, but can occur,
2769for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2770(The remainder doesn't actually overflow, but this rule lets srem be
2771implemented using instructions that return both the result of the division
2772and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2773<h5>Example:</h5>
2774<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2775</pre>
2776
2777</div>
2778<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2779<div class="doc_subsubsection">
2780 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2783
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2784<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2785<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]2786</pre>
2787<h5>Overview:</h5>
2788<p>The '<tt>frem</tt>' instruction returns the remainder from the
2789division of its two operands.</p>
2790<h5>Arguments:</h5>
2791<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2792<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2793of floating point values. Both arguments must have identical types.</p>
2794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2796
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2797<p>This instruction returns the <i>remainder</i> of a division.
2798The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2800<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2801
2802<pre>
2803 &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]2804</pre>
2805</div>
2806
2807<!-- ======================================================================= -->
2808<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2809Operations</a> </div>
2810<div class="doc_text">
2811<p>Bitwise binary operators are used to do various forms of
2812bit-twiddling in a program. They are generally very efficient
2813instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2814instructions. They require two operands of the same type, execute an operation on them,
2815and 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]2816</div>
2817
2818<!-- _______________________________________________________________________ -->
2819<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2820Instruction</a> </div>
2821<div class="doc_text">
2822<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2823<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]2824</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2825
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2826<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2828<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2829the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2830
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2831<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2833<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2834 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2835type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2836
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2837<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2838
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2839<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2840where 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]2841equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2842If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2843corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2845<h5>Example:</h5><pre>
2846 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2847 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2848 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2849 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2850 &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]2851</pre>
2852</div>
2853<!-- _______________________________________________________________________ -->
2854<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2855Instruction</a> </div>
2856<div class="doc_text">
2857<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2858<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]2859</pre>
2860
2861<h5>Overview:</h5>
2862<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2863operand shifted to the right a specified number of bits with zero fill.</p>
2864
2865<h5>Arguments:</h5>
2866<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2867<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]2868type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2869
2870<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2871
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2872<p>This instruction always performs a logical shift right operation. The most
2873significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2874shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2875the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2876vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2877amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2878
2879<h5>Example:</h5>
2880<pre>
2881 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2882 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2883 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2884 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2885 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2886 &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]2887</pre>
2888</div>
2889
2890<!-- _______________________________________________________________________ -->
2891<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2892Instruction</a> </div>
2893<div class="doc_text">
2894
2895<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2896<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]2897</pre>
2898
2899<h5>Overview:</h5>
2900<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2901operand shifted to the right a specified number of bits with sign extension.</p>
2902
2903<h5>Arguments:</h5>
2904<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2905<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]2906type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2907
2908<h5>Semantics:</h5>
2909<p>This instruction always performs an arithmetic shift right operation,
2910The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2911of <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]2912larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2913arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2914corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915
2916<h5>Example:</h5>
2917<pre>
2918 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2919 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2920 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2921 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2922 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2923 &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]2924</pre>
2925</div>
2926
2927<!-- _______________________________________________________________________ -->
2928<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2929Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2930
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2931<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2932
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2933<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2934
2935<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2936 &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]2937</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2939<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2940
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2941<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2942its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2944<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2945
2946<p>The two arguments to the '<tt>and</tt>' instruction must be
2947<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2948values. Both arguments must have identical types.</p>
2949
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2950<h5>Semantics:</h5>
2951<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2952<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2953<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2954<table border="1" cellspacing="0" cellpadding="4">
2955 <tbody>
2956 <tr>
2957 <td>In0</td>
2958 <td>In1</td>
2959 <td>Out</td>
2960 </tr>
2961 <tr>
2962 <td>0</td>
2963 <td>0</td>
2964 <td>0</td>
2965 </tr>
2966 <tr>
2967 <td>0</td>
2968 <td>1</td>
2969 <td>0</td>
2970 </tr>
2971 <tr>
2972 <td>1</td>
2973 <td>0</td>
2974 <td>0</td>
2975 </tr>
2976 <tr>
2977 <td>1</td>
2978 <td>1</td>
2979 <td>1</td>
2980 </tr>
2981 </tbody>
2982</table>
2983</div>
2984<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2985<pre>
2986 &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]2987 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2988 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2989</pre>
2990</div>
2991<!-- _______________________________________________________________________ -->
2992<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2993<div class="doc_text">
2994<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2995<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]2996</pre>
2997<h5>Overview:</h5>
2998<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2999or of its two operands.</p>
3000<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3001
3002<p>The two arguments to the '<tt>or</tt>' instruction must be
3003<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3004values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3005<h5>Semantics:</h5>
3006<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
3007<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3008<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3009<table border="1" cellspacing="0" cellpadding="4">
3010 <tbody>
3011 <tr>
3012 <td>In0</td>
3013 <td>In1</td>
3014 <td>Out</td>
3015 </tr>
3016 <tr>
3017 <td>0</td>
3018 <td>0</td>
3019 <td>0</td>
3020 </tr>
3021 <tr>
3022 <td>0</td>
3023 <td>1</td>
3024 <td>1</td>
3025 </tr>
3026 <tr>
3027 <td>1</td>
3028 <td>0</td>
3029 <td>1</td>
3030 </tr>
3031 <tr>
3032 <td>1</td>
3033 <td>1</td>
3034 <td>1</td>
3035 </tr>
3036 </tbody>
3037</table>
3038</div>
3039<h5>Example:</h5>
3040<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3041 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3042 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3043</pre>
3044</div>
3045<!-- _______________________________________________________________________ -->
3046<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3047Instruction</a> </div>
3048<div class="doc_text">
3049<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3050<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]3051</pre>
3052<h5>Overview:</h5>
3053<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3054or of its two operands. The <tt>xor</tt> is used to implement the
3055"one's complement" operation, which is the "~" operator in C.</p>
3056<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3057<p>The two arguments to the '<tt>xor</tt>' instruction must be
3058<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3059values. Both arguments must have identical types.</p>
3060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3061<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3062
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3063<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3064<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3065<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3066<table border="1" cellspacing="0" cellpadding="4">
3067 <tbody>
3068 <tr>
3069 <td>In0</td>
3070 <td>In1</td>
3071 <td>Out</td>
3072 </tr>
3073 <tr>
3074 <td>0</td>
3075 <td>0</td>
3076 <td>0</td>
3077 </tr>
3078 <tr>
3079 <td>0</td>
3080 <td>1</td>
3081 <td>1</td>
3082 </tr>
3083 <tr>
3084 <td>1</td>
3085 <td>0</td>
3086 <td>1</td>
3087 </tr>
3088 <tr>
3089 <td>1</td>
3090 <td>1</td>
3091 <td>0</td>
3092 </tr>
3093 </tbody>
3094</table>
3095</div>
3096<p> </p>
3097<h5>Example:</h5>
3098<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3099 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3100 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3101 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3102</pre>
3103</div>
3104
3105<!-- ======================================================================= -->
3106<div class="doc_subsection">
3107 <a name="vectorops">Vector Operations</a>
3108</div>
3109
3110<div class="doc_text">
3111
3112<p>LLVM supports several instructions to represent vector operations in a
3113target-independent manner. These instructions cover the element-access and
3114vector-specific operations needed to process vectors effectively. While LLVM
3115does directly support these vector operations, many sophisticated algorithms
3116will want to use target-specific intrinsics to take full advantage of a specific
3117target.</p>
3118
3119</div>
3120
3121<!-- _______________________________________________________________________ -->
3122<div class="doc_subsubsection">
3123 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3124</div>
3125
3126<div class="doc_text">
3127
3128<h5>Syntax:</h5>
3129
3130<pre>
3131 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3132</pre>
3133
3134<h5>Overview:</h5>
3135
3136<p>
3137The '<tt>extractelement</tt>' instruction extracts a single scalar
3138element from a vector at a specified index.
3139</p>
3140
3141
3142<h5>Arguments:</h5>
3143
3144<p>
3145The first operand of an '<tt>extractelement</tt>' instruction is a
3146value of <a href="#t_vector">vector</a> type. The second operand is
3147an index indicating the position from which to extract the element.
3148The index may be a variable.</p>
3149
3150<h5>Semantics:</h5>
3151
3152<p>
3153The result is a scalar of the same type as the element type of
3154<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3155<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3156results are undefined.
3157</p>
3158
3159<h5>Example:</h5>
3160
3161<pre>
3162 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3163</pre>
3164</div>
3165
3166
3167<!-- _______________________________________________________________________ -->
3168<div class="doc_subsubsection">
3169 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3170</div>
3171
3172<div class="doc_text">
3173
3174<h5>Syntax:</h5>
3175
3176<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3177 &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]3178</pre>
3179
3180<h5>Overview:</h5>
3181
3182<p>
3183The '<tt>insertelement</tt>' instruction inserts a scalar
3184element into a vector at a specified index.
3185</p>
3186
3187
3188<h5>Arguments:</h5>
3189
3190<p>
3191The first operand of an '<tt>insertelement</tt>' instruction is a
3192value of <a href="#t_vector">vector</a> type. The second operand is a
3193scalar value whose type must equal the element type of the first
3194operand. The third operand is an index indicating the position at
3195which to insert the value. The index may be a variable.</p>
3196
3197<h5>Semantics:</h5>
3198
3199<p>
3200The result is a vector of the same type as <tt>val</tt>. Its
3201element values are those of <tt>val</tt> except at position
3202<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3203exceeds the length of <tt>val</tt>, the results are undefined.
3204</p>
3205
3206<h5>Example:</h5>
3207
3208<pre>
3209 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3210</pre>
3211</div>
3212
3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection">
3215 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3216</div>
3217
3218<div class="doc_text">
3219
3220<h5>Syntax:</h5>
3221
3222<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3223 &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]3224</pre>
3225
3226<h5>Overview:</h5>
3227
3228<p>
3229The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3230from two input vectors, returning a vector with the same element type as
3231the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3232</p>
3233
3234<h5>Arguments:</h5>
3235
3236<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3237The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3238with types that match each other. The third argument is a shuffle mask whose
3239element type is always 'i32'. The result of the instruction is a vector whose
3240length is the same as the shuffle mask and whose element type is the same as
3241the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3242</p>
3243
3244<p>
3245The shuffle mask operand is required to be a constant vector with either
3246constant integer or undef values.
3247</p>
3248
3249<h5>Semantics:</h5>
3250
3251<p>
3252The elements of the two input vectors are numbered from left to right across
3253both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3254the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255gets. The element selector may be undef (meaning "don't care") and the second
3256operand may be undef if performing a shuffle from only one vector.
3257</p>
3258
3259<h5>Example:</h5>
3260
3261<pre>
3262 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3263 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3264 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3265 &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]3266 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3267 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3268 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3269 &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]3270</pre>
3271</div>
3272
3273
3274<!-- ======================================================================= -->
3275<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3276 <a name="aggregateops">Aggregate Operations</a>
3277</div>
3278
3279<div class="doc_text">
3280
3281<p>LLVM supports several instructions for working with aggregate values.
3282</p>
3283
3284</div>
3285
3286<!-- _______________________________________________________________________ -->
3287<div class="doc_subsubsection">
3288 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3289</div>
3290
3291<div class="doc_text">
3292
3293<h5>Syntax:</h5>
3294
3295<pre>
3296 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3297</pre>
3298
3299<h5>Overview:</h5>
3300
3301<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3302The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3303or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3304</p>
3305
3306
3307<h5>Arguments:</h5>
3308
3309<p>
3310The first operand of an '<tt>extractvalue</tt>' instruction is a
3311value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3312type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3313in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3314'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3315</p>
3316
3317<h5>Semantics:</h5>
3318
3319<p>
3320The result is the value at the position in the aggregate specified by
3321the index operands.
3322</p>
3323
3324<h5>Example:</h5>
3325
3326<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3327 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3328</pre>
3329</div>
3330
3331
3332<!-- _______________________________________________________________________ -->
3333<div class="doc_subsubsection">
3334 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3335</div>
3336
3337<div class="doc_text">
3338
3339<h5>Syntax:</h5>
3340
3341<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3342 &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]3343</pre>
3344
3345<h5>Overview:</h5>
3346
3347<p>
3348The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3349into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3350</p>
3351
3352
3353<h5>Arguments:</h5>
3354
3355<p>
3356The first operand of an '<tt>insertvalue</tt>' instruction is a
3357value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3358The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3359The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3360indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3361indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3362'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3363The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3364by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3365</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3366
3367<h5>Semantics:</h5>
3368
3369<p>
3370The result is an aggregate of the same type as <tt>val</tt>. Its
3371value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3372specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3373</p>
3374
3375<h5>Example:</h5>
3376
3377<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3378 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3379</pre>
3380</div>
3381
3382
3383<!-- ======================================================================= -->
3384<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3385 <a name="memoryops">Memory Access and Addressing Operations</a>
3386</div>
3387
3388<div class="doc_text">
3389
3390<p>A key design point of an SSA-based representation is how it
3391represents memory. In LLVM, no memory locations are in SSA form, which
3392makes things very simple. This section describes how to read, write,
3393allocate, and free memory in LLVM.</p>
3394
3395</div>
3396
3397<!-- _______________________________________________________________________ -->
3398<div class="doc_subsubsection">
3399 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3400</div>
3401
3402<div class="doc_text">
3403
3404<h5>Syntax:</h5>
3405
3406<pre>
3407 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3408</pre>
3409
3410<h5>Overview:</h5>
3411
3412<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3413heap and returns a pointer to it. The object is always allocated in the generic
3414address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3415
3416<h5>Arguments:</h5>
3417
3418<p>The '<tt>malloc</tt>' instruction allocates
3419<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3420bytes of memory from the operating system and returns a pointer of the
3421appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3422number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3423If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3424be aligned to at least that boundary. If not specified, or if zero, the target can
3425choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3426
3427<p>'<tt>type</tt>' must be a sized type.</p>
3428
3429<h5>Semantics:</h5>
3430
3431<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3432a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3433result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3434
3435<h5>Example:</h5>
3436
3437<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3438 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3439
3440 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3441 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3442 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3443 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3444 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3445</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3446
3447<p>Note that the code generator does not yet respect the
3448 alignment value.</p>
3449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450</div>
3451
3452<!-- _______________________________________________________________________ -->
3453<div class="doc_subsubsection">
3454 <a name="i_free">'<tt>free</tt>' Instruction</a>
3455</div>
3456
3457<div class="doc_text">
3458
3459<h5>Syntax:</h5>
3460
3461<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3462 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3463</pre>
3464
3465<h5>Overview:</h5>
3466
3467<p>The '<tt>free</tt>' instruction returns memory back to the unused
3468memory heap to be reallocated in the future.</p>
3469
3470<h5>Arguments:</h5>
3471
3472<p>'<tt>value</tt>' shall be a pointer value that points to a value
3473that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3474instruction.</p>
3475
3476<h5>Semantics:</h5>
3477
3478<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3479after this instruction executes. If the pointer is null, the operation
3480is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3481
3482<h5>Example:</h5>
3483
3484<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3485 %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]3486 free [4 x i8]* %array
3487</pre>
3488</div>
3489
3490<!-- _______________________________________________________________________ -->
3491<div class="doc_subsubsection">
3492 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3493</div>
3494
3495<div class="doc_text">
3496
3497<h5>Syntax:</h5>
3498
3499<pre>
3500 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3501</pre>
3502
3503<h5>Overview:</h5>
3504
3505<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3506currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3507returns to its caller. The object is always allocated in the generic address
3508space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3509
3510<h5>Arguments:</h5>
3511
3512<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3513bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3514appropriate type to the program. If "NumElements" is specified, it is the
3515number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3516If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3517to be aligned to at least that boundary. If not specified, or if zero, the target
3518can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3519
3520<p>'<tt>type</tt>' may be any sized type.</p>
3521
3522<h5>Semantics:</h5>
3523
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3524<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3525there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3526memory is automatically released when the function returns. The '<tt>alloca</tt>'
3527instruction is commonly used to represent automatic variables that must
3528have an address available. When the function returns (either with the <tt><a
3529 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]3530instructions), the memory is reclaimed. Allocating zero bytes
3531is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3532
3533<h5>Example:</h5>
3534
3535<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3536 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3537 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3538 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3539 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3540</pre>
3541</div>
3542
3543<!-- _______________________________________________________________________ -->
3544<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3545Instruction</a> </div>
3546<div class="doc_text">
3547<h5>Syntax:</h5>
3548<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>
3549<h5>Overview:</h5>
3550<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3551<h5>Arguments:</h5>
3552<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3553address from which to load. The pointer must point to a <a
3554 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3555marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3556the number or order of execution of this <tt>load</tt> with other
3557volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3558instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3559<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3560The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3561(that is, the alignment of the memory address). A value of 0 or an
3562omitted "align" argument means that the operation has the preferential
3563alignment for the target. It is the responsibility of the code emitter
3564to ensure that the alignment information is correct. Overestimating
3565the alignment results in an undefined behavior. Underestimating the
3566alignment may produce less efficient code. An alignment of 1 is always
3567safe.
3568</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3569<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3570<p>The location of memory pointed to is loaded. If the value being loaded
3571is of scalar type then the number of bytes read does not exceed the minimum
3572number of bytes needed to hold all bits of the type. For example, loading an
3573<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3574<tt>i20</tt> with a size that is not an integral number of bytes, the result
3575is undefined if the value was not originally written using a store of the
3576same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3577<h5>Examples:</h5>
3578<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3579 <a
3580 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3581 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3582</pre>
3583</div>
3584<!-- _______________________________________________________________________ -->
3585<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3586Instruction</a> </div>
3587<div class="doc_text">
3588<h5>Syntax:</h5>
3589<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3590 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3591</pre>
3592<h5>Overview:</h5>
3593<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3594<h5>Arguments:</h5>
3595<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3596to 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]3597operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3598of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3599operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3600optimizer is not allowed to modify the number or order of execution of
3601this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3602 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3603<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3604The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3605(that is, the alignment of the memory address). A value of 0 or an
3606omitted "align" argument means that the operation has the preferential
3607alignment for the target. It is the responsibility of the code emitter
3608to ensure that the alignment information is correct. Overestimating
3609the alignment results in an undefined behavior. Underestimating the
3610alignment may produce less efficient code. An alignment of 1 is always
3611safe.
3612</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3613<h5>Semantics:</h5>
3614<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3615at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3616If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3617written does not exceed the minimum number of bytes needed to hold all
3618bits of the type. For example, storing an <tt>i24</tt> writes at most
3619three bytes. When writing a value of a type like <tt>i20</tt> with a
3620size that is not an integral number of bytes, it is unspecified what
3621happens to the extra bits that do not belong to the type, but they will
3622typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3623<h5>Example:</h5>
3624<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3625 store i32 3, i32* %ptr <i>; yields {void}</i>
3626 %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]3627</pre>
3628</div>
3629
3630<!-- _______________________________________________________________________ -->
3631<div class="doc_subsubsection">
3632 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3633</div>
3634
3635<div class="doc_text">
3636<h5>Syntax:</h5>
3637<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3638 &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]3639</pre>
3640
3641<h5>Overview:</h5>
3642
3643<p>
3644The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3645subelement of an aggregate data structure. It performs address calculation only
3646and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647
3648<h5>Arguments:</h5>
3649
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3650<p>The first argument is always a pointer, and forms the basis of the
3651calculation. The remaining arguments are indices, that indicate which of the
3652elements of the aggregate object are indexed. The interpretation of each index
3653is dependent on the type being indexed into. The first index always indexes the
3654pointer value given as the first argument, the second index indexes a value of
3655the type pointed to (not necessarily the value directly pointed to, since the
3656first index can be non-zero), etc. The first type indexed into must be a pointer
3657value, subsequent types can be arrays, vectors and structs. Note that subsequent
3658types being indexed into can never be pointers, since that would require loading
3659the pointer before continuing calculation.</p>
3660
3661<p>The type of each index argument depends on the type it is indexing into.
3662When indexing into a (packed) structure, only <tt>i32</tt> integer
3663<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3664integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3665
3666<p>For example, let's consider a C code fragment and how it gets
3667compiled to LLVM:</p>
3668
3669<div class="doc_code">
3670<pre>
3671struct RT {
3672 char A;
3673 int B[10][20];
3674 char C;
3675};
3676struct ST {
3677 int X;
3678 double Y;
3679 struct RT Z;
3680};
3681
3682int *foo(struct ST *s) {
3683 return &amp;s[1].Z.B[5][13];
3684}
3685</pre>
3686</div>
3687
3688<p>The LLVM code generated by the GCC frontend is:</p>
3689
3690<div class="doc_code">
3691<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3692%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3693%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3694
3695define i32* %foo(%ST* %s) {
3696entry:
3697 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3698 ret i32* %reg
3699}
3700</pre>
3701</div>
3702
3703<h5>Semantics:</h5>
3704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3706type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3707}</tt>' type, a structure. The second index indexes into the third element of
3708the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3709i8 }</tt>' type, another structure. The third index indexes into the second
3710element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3711array. The two dimensions of the array are subscripted into, yielding an
3712'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3713to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3714
3715<p>Note that it is perfectly legal to index partially through a
3716structure, returning a pointer to an inner element. Because of this,
3717the LLVM code for the given testcase is equivalent to:</p>
3718
3719<pre>
3720 define i32* %foo(%ST* %s) {
3721 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3722 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3723 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3724 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3725 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3726 ret i32* %t5
3727 }
3728</pre>
3729
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3730<p>Note that it is undefined to access an array out of bounds: array
3731and pointer indexes must always be within the defined bounds of the
3732array type when accessed with an instruction that dereferences the
3733pointer (e.g. a load or store instruction). The one exception for
3734this rule is zero length arrays. These arrays are defined to be
3735accessible as variable length arrays, which requires access beyond the
3736zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3737
3738<p>The getelementptr instruction is often confusing. For some more insight
3739into how it works, see <a href="GetElementPtr.html">the getelementptr
3740FAQ</a>.</p>
3741
3742<h5>Example:</h5>
3743
3744<pre>
3745 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3746 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3747 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3748 %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]3749 <i>; yields i8*:eptr</i>
3750 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3751 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3752 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3753</pre>
3754</div>
3755
3756<!-- ======================================================================= -->
3757<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3758</div>
3759<div class="doc_text">
3760<p>The instructions in this category are the conversion instructions (casting)
3761which all take a single operand and a type. They perform various bit conversions
3762on the operand.</p>
3763</div>
3764
3765<!-- _______________________________________________________________________ -->
3766<div class="doc_subsubsection">
3767 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3768</div>
3769<div class="doc_text">
3770
3771<h5>Syntax:</h5>
3772<pre>
3773 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3774</pre>
3775
3776<h5>Overview:</h5>
3777<p>
3778The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3779</p>
3780
3781<h5>Arguments:</h5>
3782<p>
3783The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3784be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3785and type of the result, which must be an <a href="#t_integer">integer</a>
3786type. The bit size of <tt>value</tt> must be larger than the bit size of
3787<tt>ty2</tt>. Equal sized types are not allowed.</p>
3788
3789<h5>Semantics:</h5>
3790<p>
3791The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3792and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3793larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3794It will always truncate bits.</p>
3795
3796<h5>Example:</h5>
3797<pre>
3798 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3799 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3800 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3801</pre>
3802</div>
3803
3804<!-- _______________________________________________________________________ -->
3805<div class="doc_subsubsection">
3806 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3807</div>
3808<div class="doc_text">
3809
3810<h5>Syntax:</h5>
3811<pre>
3812 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3813</pre>
3814
3815<h5>Overview:</h5>
3816<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3817<tt>ty2</tt>.</p>
3818
3819
3820<h5>Arguments:</h5>
3821<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3822<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3823also be of <a href="#t_integer">integer</a> type. The bit size of the
3824<tt>value</tt> must be smaller than the bit size of the destination type,
3825<tt>ty2</tt>.</p>
3826
3827<h5>Semantics:</h5>
3828<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3829bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3830
3831<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3832
3833<h5>Example:</h5>
3834<pre>
3835 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3836 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3837</pre>
3838</div>
3839
3840<!-- _______________________________________________________________________ -->
3841<div class="doc_subsubsection">
3842 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3843</div>
3844<div class="doc_text">
3845
3846<h5>Syntax:</h5>
3847<pre>
3848 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3849</pre>
3850
3851<h5>Overview:</h5>
3852<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3853
3854<h5>Arguments:</h5>
3855<p>
3856The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3857<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3858also be of <a href="#t_integer">integer</a> type. The bit size of the
3859<tt>value</tt> must be smaller than the bit size of the destination type,
3860<tt>ty2</tt>.</p>
3861
3862<h5>Semantics:</h5>
3863<p>
3864The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3865bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3866the type <tt>ty2</tt>.</p>
3867
3868<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3869
3870<h5>Example:</h5>
3871<pre>
3872 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3873 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3874</pre>
3875</div>
3876
3877<!-- _______________________________________________________________________ -->
3878<div class="doc_subsubsection">
3879 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3880</div>
3881
3882<div class="doc_text">
3883
3884<h5>Syntax:</h5>
3885
3886<pre>
3887 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3888</pre>
3889
3890<h5>Overview:</h5>
3891<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3892<tt>ty2</tt>.</p>
3893
3894
3895<h5>Arguments:</h5>
3896<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3897 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3898cast it to. The size of <tt>value</tt> must be larger than the size of
3899<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3900<i>no-op cast</i>.</p>
3901
3902<h5>Semantics:</h5>
3903<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3904<a href="#t_floating">floating point</a> type to a smaller
3905<a href="#t_floating">floating point</a> type. If the value cannot fit within
3906the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3907
3908<h5>Example:</h5>
3909<pre>
3910 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3911 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3912</pre>
3913</div>
3914
3915<!-- _______________________________________________________________________ -->
3916<div class="doc_subsubsection">
3917 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3918</div>
3919<div class="doc_text">
3920
3921<h5>Syntax:</h5>
3922<pre>
3923 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3924</pre>
3925
3926<h5>Overview:</h5>
3927<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3928floating point value.</p>
3929
3930<h5>Arguments:</h5>
3931<p>The '<tt>fpext</tt>' instruction takes a
3932<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3933and a <a href="#t_floating">floating point</a> type to cast it to. The source
3934type must be smaller than the destination type.</p>
3935
3936<h5>Semantics:</h5>
3937<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3938<a href="#t_floating">floating point</a> type to a larger
3939<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3940used to make a <i>no-op cast</i> because it always changes bits. Use
3941<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3942
3943<h5>Example:</h5>
3944<pre>
3945 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3946 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3947</pre>
3948</div>
3949
3950<!-- _______________________________________________________________________ -->
3951<div class="doc_subsubsection">
3952 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3953</div>
3954<div class="doc_text">
3955
3956<h5>Syntax:</h5>
3957<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3958 &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]3959</pre>
3960
3961<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3962<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3963unsigned integer equivalent of type <tt>ty2</tt>.
3964</p>
3965
3966<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3967<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]3968scalar or vector <a href="#t_floating">floating point</a> value, and a type
3969to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3970type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3971vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3972
3973<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3974<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3975<a href="#t_floating">floating point</a> operand into the nearest (rounding
3976towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3977the results are undefined.</p>
3978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979<h5>Example:</h5>
3980<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3981 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3982 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3983 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3984</pre>
3985</div>
3986
3987<!-- _______________________________________________________________________ -->
3988<div class="doc_subsubsection">
3989 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3990</div>
3991<div class="doc_text">
3992
3993<h5>Syntax:</h5>
3994<pre>
3995 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3996</pre>
3997
3998<h5>Overview:</h5>
3999<p>The '<tt>fptosi</tt>' instruction converts
4000<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
4001</p>
4002
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4003<h5>Arguments:</h5>
4004<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]4005scalar or vector <a href="#t_floating">floating point</a> value, and a type
4006to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4007type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4008vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4009
4010<h5>Semantics:</h5>
4011<p>The '<tt>fptosi</tt>' instruction converts its
4012<a href="#t_floating">floating point</a> operand into the nearest (rounding
4013towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4014the results are undefined.</p>
4015
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4016<h5>Example:</h5>
4017<pre>
4018 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4019 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4020 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4021</pre>
4022</div>
4023
4024<!-- _______________________________________________________________________ -->
4025<div class="doc_subsubsection">
4026 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4027</div>
4028<div class="doc_text">
4029
4030<h5>Syntax:</h5>
4031<pre>
4032 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4033</pre>
4034
4035<h5>Overview:</h5>
4036<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4037integer and converts that value to the <tt>ty2</tt> type.</p>
4038
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4039<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4040<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4041scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4042to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4043type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4044floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4045
4046<h5>Semantics:</h5>
4047<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4048integer quantity and converts it to the corresponding floating point value. If
4049the value cannot fit in the floating point value, the results are undefined.</p>
4050
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4051<h5>Example:</h5>
4052<pre>
4053 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4054 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4055</pre>
4056</div>
4057
4058<!-- _______________________________________________________________________ -->
4059<div class="doc_subsubsection">
4060 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4061</div>
4062<div class="doc_text">
4063
4064<h5>Syntax:</h5>
4065<pre>
4066 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4067</pre>
4068
4069<h5>Overview:</h5>
4070<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4071integer and converts that value to the <tt>ty2</tt> type.</p>
4072
4073<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4074<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4075scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4076to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4077type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4078floating point 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>
4081<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4082integer quantity and converts it to the corresponding floating point value. If
4083the value cannot fit in the floating point value, the results are undefined.</p>
4084
4085<h5>Example:</h5>
4086<pre>
4087 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4088 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4089</pre>
4090</div>
4091
4092<!-- _______________________________________________________________________ -->
4093<div class="doc_subsubsection">
4094 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4095</div>
4096<div class="doc_text">
4097
4098<h5>Syntax:</h5>
4099<pre>
4100 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4101</pre>
4102
4103<h5>Overview:</h5>
4104<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4105the integer type <tt>ty2</tt>.</p>
4106
4107<h5>Arguments:</h5>
4108<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4109must 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]4110<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]4111
4112<h5>Semantics:</h5>
4113<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4114<tt>ty2</tt> by interpreting the pointer value as an integer and either
4115truncating or zero extending that value to the size of the integer type. If
4116<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4117<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4118are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4119change.</p>
4120
4121<h5>Example:</h5>
4122<pre>
4123 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4124 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4125</pre>
4126</div>
4127
4128<!-- _______________________________________________________________________ -->
4129<div class="doc_subsubsection">
4130 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4131</div>
4132<div class="doc_text">
4133
4134<h5>Syntax:</h5>
4135<pre>
4136 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4137</pre>
4138
4139<h5>Overview:</h5>
4140<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4141a pointer type, <tt>ty2</tt>.</p>
4142
4143<h5>Arguments:</h5>
4144<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4145value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4146<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147
4148<h5>Semantics:</h5>
4149<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4150<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4151the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4152size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4153the size of a pointer then a zero extension is done. If they are the same size,
4154nothing is done (<i>no-op cast</i>).</p>
4155
4156<h5>Example:</h5>
4157<pre>
4158 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4159 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4160 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4161</pre>
4162</div>
4163
4164<!-- _______________________________________________________________________ -->
4165<div class="doc_subsubsection">
4166 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4167</div>
4168<div class="doc_text">
4169
4170<h5>Syntax:</h5>
4171<pre>
4172 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4173</pre>
4174
4175<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4176
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4177<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4178<tt>ty2</tt> without changing any bits.</p>
4179
4180<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4182<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4183a non-aggregate first class value, and a type to cast it to, which must also be
4184a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4185<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4186and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4187type is a pointer, the destination type must also be a pointer. This
4188instruction supports bitwise conversion of vectors to integers and to vectors
4189of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4190
4191<h5>Semantics:</h5>
4192<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4193<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4194this conversion. The conversion is done as if the <tt>value</tt> had been
4195stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4196converted to other pointer types with this instruction. To convert pointers to
4197other types, use the <a href="#i_inttoptr">inttoptr</a> or
4198<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4199
4200<h5>Example:</h5>
4201<pre>
4202 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4203 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4204 %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]4205</pre>
4206</div>
4207
4208<!-- ======================================================================= -->
4209<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4210<div class="doc_text">
4211<p>The instructions in this category are the "miscellaneous"
4212instructions, which defy better classification.</p>
4213</div>
4214
4215<!-- _______________________________________________________________________ -->
4216<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4217</div>
4218<div class="doc_text">
4219<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4220<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]4221</pre>
4222<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4223<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4224a vector of boolean values based on comparison
4225of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4226<h5>Arguments:</h5>
4227<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4228the condition code indicating the kind of comparison to perform. It is not
4229a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4230</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4231<ol>
4232 <li><tt>eq</tt>: equal</li>
4233 <li><tt>ne</tt>: not equal </li>
4234 <li><tt>ugt</tt>: unsigned greater than</li>
4235 <li><tt>uge</tt>: unsigned greater or equal</li>
4236 <li><tt>ult</tt>: unsigned less than</li>
4237 <li><tt>ule</tt>: unsigned less or equal</li>
4238 <li><tt>sgt</tt>: signed greater than</li>
4239 <li><tt>sge</tt>: signed greater or equal</li>
4240 <li><tt>slt</tt>: signed less than</li>
4241 <li><tt>sle</tt>: signed less or equal</li>
4242</ol>
4243<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4244<a href="#t_pointer">pointer</a>
4245or integer <a href="#t_vector">vector</a> typed.
4246They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4248<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]4249the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4250yields 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]4251</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4252<ol>
4253 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4254 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4255 </li>
4256 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4257 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4259 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4261 <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]4262 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4263 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4265 <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]4266 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4267 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4269 <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]4270 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4271 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4273 <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]4274</ol>
4275<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4276values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4277<p>If the operands are integer vectors, then they are compared
4278element by element. The result is an <tt>i1</tt> vector with
4279the same number of elements as the values being compared.
4280Otherwise, the result is an <tt>i1</tt>.
4281</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4282
4283<h5>Example:</h5>
4284<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4285 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4286 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4287 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4288 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4289 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4290</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4291
4292<p>Note that the code generator does not yet support vector types with
4293 the <tt>icmp</tt> instruction.</p>
4294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4295</div>
4296
4297<!-- _______________________________________________________________________ -->
4298<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4299</div>
4300<div class="doc_text">
4301<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4302<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]4303</pre>
4304<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4305<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4306or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4307of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4308<p>
4309If the operands are floating point scalars, then the result
4310type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4311</p>
4312<p>If the operands are floating point vectors, then the result type
4313is a vector of boolean with the same number of elements as the
4314operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4315<h5>Arguments:</h5>
4316<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4317the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4318a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4319<ol>
4320 <li><tt>false</tt>: no comparison, always returns false</li>
4321 <li><tt>oeq</tt>: ordered and equal</li>
4322 <li><tt>ogt</tt>: ordered and greater than </li>
4323 <li><tt>oge</tt>: ordered and greater than or equal</li>
4324 <li><tt>olt</tt>: ordered and less than </li>
4325 <li><tt>ole</tt>: ordered and less than or equal</li>
4326 <li><tt>one</tt>: ordered and not equal</li>
4327 <li><tt>ord</tt>: ordered (no nans)</li>
4328 <li><tt>ueq</tt>: unordered or equal</li>
4329 <li><tt>ugt</tt>: unordered or greater than </li>
4330 <li><tt>uge</tt>: unordered or greater than or equal</li>
4331 <li><tt>ult</tt>: unordered or less than </li>
4332 <li><tt>ule</tt>: unordered or less than or equal</li>
4333 <li><tt>une</tt>: unordered or not equal</li>
4334 <li><tt>uno</tt>: unordered (either nans)</li>
4335 <li><tt>true</tt>: no comparison, always returns true</li>
4336</ol>
4337<p><i>Ordered</i> means that neither operand is a QNAN while
4338<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4339<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4340either a <a href="#t_floating">floating point</a> type
4341or a <a href="#t_vector">vector</a> of floating point type.
4342They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4343<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4344<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4345according to the condition code given as <tt>cond</tt>.
4346If the operands are vectors, then the vectors are compared
4347element by element.
4348Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4349always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4350<ol>
4351 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4352 <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]4353 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4354 <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]4355 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4356 <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]4357 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4358 <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]4359 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4360 <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]4361 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4362 <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]4363 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4364 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4365 <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]4366 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4367 <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]4368 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369 <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]4370 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4371 <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]4372 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4373 <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]4374 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375 <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]4376 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4377 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4378 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4379</ol>
4380
4381<h5>Example:</h5>
4382<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]4383 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4384 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4385 &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]4386</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4387
4388<p>Note that the code generator does not yet support vector types with
4389 the <tt>fcmp</tt> instruction.</p>
4390
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4391</div>
4392
4393<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4394<div class="doc_subsubsection">
4395 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4396</div>
4397<div class="doc_text">
4398<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4399<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4400</pre>
4401<h5>Overview:</h5>
4402<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4403element-wise comparison of its two integer vector operands.</p>
4404<h5>Arguments:</h5>
4405<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4406the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4407a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4408<ol>
4409 <li><tt>eq</tt>: equal</li>
4410 <li><tt>ne</tt>: not equal </li>
4411 <li><tt>ugt</tt>: unsigned greater than</li>
4412 <li><tt>uge</tt>: unsigned greater or equal</li>
4413 <li><tt>ult</tt>: unsigned less than</li>
4414 <li><tt>ule</tt>: unsigned less or equal</li>
4415 <li><tt>sgt</tt>: signed greater than</li>
4416 <li><tt>sge</tt>: signed greater or equal</li>
4417 <li><tt>slt</tt>: signed less than</li>
4418 <li><tt>sle</tt>: signed less or equal</li>
4419</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4420<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4421<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4422<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4423<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4424according to the condition code given as <tt>cond</tt>. The comparison yields a
4425<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4426identical type as the values being compared. The most significant bit in each
4427element is 1 if the element-wise comparison evaluates to true, and is 0
4428otherwise. All other bits of the result are undefined. The condition codes
4429are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4430instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4431
4432<h5>Example:</h5>
4433<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4434 &lt;result&gt; = vicmp eq &lt;2 x i32&gt; &lt; i32 4, i32 0&gt;, &lt; i32 5, i32 0&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4435 &lt;result&gt; = vicmp ult &lt;2 x i8 &gt; &lt; i8 1, i8 2&gt;, &lt; i8 2, i8 2 &gt; <i>; yields: result=&lt;2 x i8&gt; &lt; i8 -1, i8 0 &gt;</i>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4436</pre>
4437</div>
4438
4439<!-- _______________________________________________________________________ -->
4440<div class="doc_subsubsection">
4441 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4442</div>
4443<div class="doc_text">
4444<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4445<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt;</pre>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4446<h5>Overview:</h5>
4447<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4448element-wise comparison of its two floating point vector operands. The output
4449elements have the same width as the input elements.</p>
4450<h5>Arguments:</h5>
4451<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4452the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4453a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4454<ol>
4455 <li><tt>false</tt>: no comparison, always returns false</li>
4456 <li><tt>oeq</tt>: ordered and equal</li>
4457 <li><tt>ogt</tt>: ordered and greater than </li>
4458 <li><tt>oge</tt>: ordered and greater than or equal</li>
4459 <li><tt>olt</tt>: ordered and less than </li>
4460 <li><tt>ole</tt>: ordered and less than or equal</li>
4461 <li><tt>one</tt>: ordered and not equal</li>
4462 <li><tt>ord</tt>: ordered (no nans)</li>
4463 <li><tt>ueq</tt>: unordered or equal</li>
4464 <li><tt>ugt</tt>: unordered or greater than </li>
4465 <li><tt>uge</tt>: unordered or greater than or equal</li>
4466 <li><tt>ult</tt>: unordered or less than </li>
4467 <li><tt>ule</tt>: unordered or less than or equal</li>
4468 <li><tt>une</tt>: unordered or not equal</li>
4469 <li><tt>uno</tt>: unordered (either nans)</li>
4470 <li><tt>true</tt>: no comparison, always returns true</li>
4471</ol>
4472<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4473<a href="#t_floating">floating point</a> typed. They must also be identical
4474types.</p>
4475<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4476<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4477according to the condition code given as <tt>cond</tt>. The comparison yields a
4478<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4479an identical number of elements as the values being compared, and each element
4480having identical with to the width of the floating point elements. The most
4481significant bit in each element is 1 if the element-wise comparison evaluates to
4482true, and is 0 otherwise. All other bits of the result are undefined. The
4483condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4484<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4485
4486<h5>Example:</h5>
4487<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4488 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4489 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4490
4491 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4492 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt;
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4493</pre>
4494</div>
4495
4496<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4497<div class="doc_subsubsection">
4498 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4499</div>
4500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4501<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4503<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4504
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4505<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4506<h5>Overview:</h5>
4507<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4508the SSA graph representing the function.</p>
4509<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511<p>The type of the incoming values is specified with the first type
4512field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4513as arguments, with one pair for each predecessor basic block of the
4514current block. Only values of <a href="#t_firstclass">first class</a>
4515type may be used as the value arguments to the PHI node. Only labels
4516may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4518<p>There must be no non-phi instructions between the start of a basic
4519block and the PHI instructions: i.e. PHI instructions must be first in
4520a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4521
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4522<p>For the purposes of the SSA form, the use of each incoming value is
4523deemed to occur on the edge from the corresponding predecessor block
4524to the current block (but after any definition of an '<tt>invoke</tt>'
4525instruction's return value on the same edge).</p>
4526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4527<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4530specified by the pair corresponding to the predecessor basic block that executed
4531just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4532
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4533<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4534<pre>
4535Loop: ; Infinite loop that counts from 0 on up...
4536 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4537 %nextindvar = add i32 %indvar, 1
4538 br label %Loop
4539</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540</div>
4541
4542<!-- _______________________________________________________________________ -->
4543<div class="doc_subsubsection">
4544 <a name="i_select">'<tt>select</tt>' Instruction</a>
4545</div>
4546
4547<div class="doc_text">
4548
4549<h5>Syntax:</h5>
4550
4551<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4552 &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>
4553
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4554 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4555</pre>
4556
4557<h5>Overview:</h5>
4558
4559<p>
4560The '<tt>select</tt>' instruction is used to choose one value based on a
4561condition, without branching.
4562</p>
4563
4564
4565<h5>Arguments:</h5>
4566
4567<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4568The '<tt>select</tt>' instruction requires an 'i1' value or
4569a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4570condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4571type. If the val1/val2 are vectors and
4572the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4573individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4574</p>
4575
4576<h5>Semantics:</h5>
4577
4578<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4579If 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]4580value argument; otherwise, it returns the second value argument.
4581</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4582<p>
4583If the condition is a vector of i1, then the value arguments must
4584be vectors of the same size, and the selection is done element
4585by element.
4586</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4587
4588<h5>Example:</h5>
4589
4590<pre>
4591 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4592</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4593
4594<p>Note that the code generator does not yet support conditions
4595 with vector type.</p>
4596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4597</div>
4598
4599
4600<!-- _______________________________________________________________________ -->
4601<div class="doc_subsubsection">
4602 <a name="i_call">'<tt>call</tt>' Instruction</a>
4603</div>
4604
4605<div class="doc_text">
4606
4607<h5>Syntax:</h5>
4608<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4609 &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]4610</pre>
4611
4612<h5>Overview:</h5>
4613
4614<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4615
4616<h5>Arguments:</h5>
4617
4618<p>This instruction requires several arguments:</p>
4619
4620<ol>
4621 <li>
4622 <p>The optional "tail" marker indicates whether the callee function accesses
4623 any allocas or varargs in the caller. If the "tail" marker is present, the
4624 function call is eligible for tail call optimization. Note that calls may
4625 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4626 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4627 </li>
4628 <li>
4629 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4630 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4631 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4632 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4633
4634 <li>
4635 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4636 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4637 and '<tt>inreg</tt>' attributes are valid here.</p>
4638 </li>
4639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4640 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4641 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4642 the type of the return value. Functions that return no value are marked
4643 <tt><a href="#t_void">void</a></tt>.</p>
4644 </li>
4645 <li>
4646 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4647 value being invoked. The argument types must match the types implied by
4648 this signature. This type can be omitted if the function is not varargs
4649 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4650 </li>
4651 <li>
4652 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4653 be invoked. In most cases, this is a direct function invocation, but
4654 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4655 to function value.</p>
4656 </li>
4657 <li>
4658 <p>'<tt>function args</tt>': argument list whose types match the
4659 function signature argument types. All arguments must be of
4660 <a href="#t_firstclass">first class</a> type. If the function signature
4661 indicates the function accepts a variable number of arguments, the extra
4662 arguments can be specified.</p>
4663 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4664 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4665 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4666 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4667 '<tt>readnone</tt>' attributes are valid here.</p>
4668 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4669</ol>
4670
4671<h5>Semantics:</h5>
4672
4673<p>The '<tt>call</tt>' instruction is used to cause control flow to
4674transfer to a specified function, with its incoming arguments bound to
4675the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4676instruction in the called function, control flow continues with the
4677instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4678function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4679
4680<h5>Example:</h5>
4681
4682<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4683 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4684 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4685 %X = tail call i32 @foo() <i>; yields i32</i>
4686 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4687 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4688
4689 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4690 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4691 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4692 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4693 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4694 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4695</pre>
4696
4697</div>
4698
4699<!-- _______________________________________________________________________ -->
4700<div class="doc_subsubsection">
4701 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4702</div>
4703
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707
4708<pre>
4709 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4710</pre>
4711
4712<h5>Overview:</h5>
4713
4714<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4715the "variable argument" area of a function call. It is used to implement the
4716<tt>va_arg</tt> macro in C.</p>
4717
4718<h5>Arguments:</h5>
4719
4720<p>This instruction takes a <tt>va_list*</tt> value and the type of
4721the argument. It returns a value of the specified argument type and
4722increments the <tt>va_list</tt> to point to the next argument. The
4723actual type of <tt>va_list</tt> is target specific.</p>
4724
4725<h5>Semantics:</h5>
4726
4727<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4728type from the specified <tt>va_list</tt> and causes the
4729<tt>va_list</tt> to point to the next argument. For more information,
4730see the variable argument handling <a href="#int_varargs">Intrinsic
4731Functions</a>.</p>
4732
4733<p>It is legal for this instruction to be called in a function which does not
4734take a variable number of arguments, for example, the <tt>vfprintf</tt>
4735function.</p>
4736
4737<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4738href="#intrinsics">intrinsic function</a> because it takes a type as an
4739argument.</p>
4740
4741<h5>Example:</h5>
4742
4743<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4744
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4745<p>Note that the code generator does not yet fully support va_arg
4746 on many targets. Also, it does not currently support va_arg with
4747 aggregate types on any target.</p>
4748
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4749</div>
4750
4751<!-- *********************************************************************** -->
4752<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4753<!-- *********************************************************************** -->
4754
4755<div class="doc_text">
4756
4757<p>LLVM supports the notion of an "intrinsic function". These functions have
4758well known names and semantics and are required to follow certain restrictions.
4759Overall, these intrinsics represent an extension mechanism for the LLVM
4760language that does not require changing all of the transformations in LLVM when
4761adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4762
4763<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4764prefix is reserved in LLVM for intrinsic names; thus, function names may not
4765begin with this prefix. Intrinsic functions must always be external functions:
4766you cannot define the body of intrinsic functions. Intrinsic functions may
4767only be used in call or invoke instructions: it is illegal to take the address
4768of an intrinsic function. Additionally, because intrinsic functions are part
4769of the LLVM language, it is required if any are added that they be documented
4770here.</p>
4771
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4772<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4773a family of functions that perform the same operation but on different data
4774types. Because LLVM can represent over 8 million different integer types,
4775overloading is used commonly to allow an intrinsic function to operate on any
4776integer type. One or more of the argument types or the result type can be
4777overloaded to accept any integer type. Argument types may also be defined as
4778exactly matching a previous argument's type or the result type. This allows an
4779intrinsic function which accepts multiple arguments, but needs all of them to
4780be of the same type, to only be overloaded with respect to a single argument or
4781the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4782
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4783<p>Overloaded intrinsics will have the names of its overloaded argument types
4784encoded into its function name, each preceded by a period. Only those types
4785which are overloaded result in a name suffix. Arguments whose type is matched
4786against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4787take an integer of any width and returns an integer of exactly the same integer
4788width. This leads to a family of functions such as
4789<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4790Only one type, the return type, is overloaded, and only one type suffix is
4791required. Because the argument's type is matched against the return type, it
4792does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4793
4794<p>To learn how to add an intrinsic function, please see the
4795<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4796</p>
4797
4798</div>
4799
4800<!-- ======================================================================= -->
4801<div class="doc_subsection">
4802 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4803</div>
4804
4805<div class="doc_text">
4806
4807<p>Variable argument support is defined in LLVM with the <a
4808 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4809intrinsic functions. These functions are related to the similarly
4810named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4811
4812<p>All of these functions operate on arguments that use a
4813target-specific value type "<tt>va_list</tt>". The LLVM assembly
4814language reference manual does not define what this type is, so all
4815transformations should be prepared to handle these functions regardless of
4816the type used.</p>
4817
4818<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4819instruction and the variable argument handling intrinsic functions are
4820used.</p>
4821
4822<div class="doc_code">
4823<pre>
4824define i32 @test(i32 %X, ...) {
4825 ; Initialize variable argument processing
4826 %ap = alloca i8*
4827 %ap2 = bitcast i8** %ap to i8*
4828 call void @llvm.va_start(i8* %ap2)
4829
4830 ; Read a single integer argument
4831 %tmp = va_arg i8** %ap, i32
4832
4833 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4834 %aq = alloca i8*
4835 %aq2 = bitcast i8** %aq to i8*
4836 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4837 call void @llvm.va_end(i8* %aq2)
4838
4839 ; Stop processing of arguments.
4840 call void @llvm.va_end(i8* %ap2)
4841 ret i32 %tmp
4842}
4843
4844declare void @llvm.va_start(i8*)
4845declare void @llvm.va_copy(i8*, i8*)
4846declare void @llvm.va_end(i8*)
4847</pre>
4848</div>
4849
4850</div>
4851
4852<!-- _______________________________________________________________________ -->
4853<div class="doc_subsubsection">
4854 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4855</div>
4856
4857
4858<div class="doc_text">
4859<h5>Syntax:</h5>
4860<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4861<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4862<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4863<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4864href="#i_va_arg">va_arg</a></tt>.</p>
4865
4866<h5>Arguments:</h5>
4867
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4868<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]4869
4870<h5>Semantics:</h5>
4871
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4872<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]4873macro available in C. In a target-dependent way, it initializes the
4874<tt>va_list</tt> element to which the argument points, so that the next call to
4875<tt>va_arg</tt> will produce the first variable argument passed to the function.
4876Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4877last argument of the function as the compiler can figure that out.</p>
4878
4879</div>
4880
4881<!-- _______________________________________________________________________ -->
4882<div class="doc_subsubsection">
4883 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4884</div>
4885
4886<div class="doc_text">
4887<h5>Syntax:</h5>
4888<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4889<h5>Overview:</h5>
4890
4891<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4892which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4893or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4894
4895<h5>Arguments:</h5>
4896
4897<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4898
4899<h5>Semantics:</h5>
4900
4901<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4902macro available in C. In a target-dependent way, it destroys the
4903<tt>va_list</tt> element to which the argument points. Calls to <a
4904href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4905<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4906<tt>llvm.va_end</tt>.</p>
4907
4908</div>
4909
4910<!-- _______________________________________________________________________ -->
4911<div class="doc_subsubsection">
4912 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4913</div>
4914
4915<div class="doc_text">
4916
4917<h5>Syntax:</h5>
4918
4919<pre>
4920 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4921</pre>
4922
4923<h5>Overview:</h5>
4924
4925<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4926from the source argument list to the destination argument list.</p>
4927
4928<h5>Arguments:</h5>
4929
4930<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4931The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4932
4933
4934<h5>Semantics:</h5>
4935
4936<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4937macro available in C. In a target-dependent way, it copies the source
4938<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4939intrinsic is necessary because the <tt><a href="#int_va_start">
4940llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4941example, memory allocation.</p>
4942
4943</div>
4944
4945<!-- ======================================================================= -->
4946<div class="doc_subsection">
4947 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4948</div>
4949
4950<div class="doc_text">
4951
4952<p>
4953LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4954Collection</a> (GC) requires the implementation and generation of these
4955intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4956These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4957stack</a>, as well as garbage collector implementations that require <a
4958href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4959Front-ends for type-safe garbage collected languages should generate these
4960intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4961href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4962</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4963
4964<p>The garbage collection intrinsics only operate on objects in the generic
4965 address space (address space zero).</p>
4966
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4967</div>
4968
4969<!-- _______________________________________________________________________ -->
4970<div class="doc_subsubsection">
4971 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4972</div>
4973
4974<div class="doc_text">
4975
4976<h5>Syntax:</h5>
4977
4978<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4979 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4980</pre>
4981
4982<h5>Overview:</h5>
4983
4984<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4985the code generator, and allows some metadata to be associated with it.</p>
4986
4987<h5>Arguments:</h5>
4988
4989<p>The first argument specifies the address of a stack object that contains the
4990root pointer. The second pointer (which must be either a constant or a global
4991value address) contains the meta-data to be associated with the root.</p>
4992
4993<h5>Semantics:</h5>
4994
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4995<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]4996location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4997the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4998intrinsic may only be used in a function which <a href="#gc">specifies a GC
4999algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5000
5001</div>
5002
5003
5004<!-- _______________________________________________________________________ -->
5005<div class="doc_subsubsection">
5006 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5007</div>
5008
5009<div class="doc_text">
5010
5011<h5>Syntax:</h5>
5012
5013<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5014 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5015</pre>
5016
5017<h5>Overview:</h5>
5018
5019<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
5020locations, allowing garbage collector implementations that require read
5021barriers.</p>
5022
5023<h5>Arguments:</h5>
5024
5025<p>The second argument is the address to read from, which should be an address
5026allocated from the garbage collector. The first object is a pointer to the
5027start of the referenced object, if needed by the language runtime (otherwise
5028null).</p>
5029
5030<h5>Semantics:</h5>
5031
5032<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5033instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5034garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5035may only be used in a function which <a href="#gc">specifies a GC
5036algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5037
5038</div>
5039
5040
5041<!-- _______________________________________________________________________ -->
5042<div class="doc_subsubsection">
5043 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5044</div>
5045
5046<div class="doc_text">
5047
5048<h5>Syntax:</h5>
5049
5050<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5051 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5052</pre>
5053
5054<h5>Overview:</h5>
5055
5056<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5057locations, allowing garbage collector implementations that require write
5058barriers (such as generational or reference counting collectors).</p>
5059
5060<h5>Arguments:</h5>
5061
5062<p>The first argument is the reference to store, the second is the start of the
5063object to store it to, and the third is the address of the field of Obj to
5064store to. If the runtime does not require a pointer to the object, Obj may be
5065null.</p>
5066
5067<h5>Semantics:</h5>
5068
5069<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5070instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5071garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5072may only be used in a function which <a href="#gc">specifies a GC
5073algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074
5075</div>
5076
5077
5078
5079<!-- ======================================================================= -->
5080<div class="doc_subsection">
5081 <a name="int_codegen">Code Generator Intrinsics</a>
5082</div>
5083
5084<div class="doc_text">
5085<p>
5086These intrinsics are provided by LLVM to expose special features that may only
5087be implemented with code generator support.
5088</p>
5089
5090</div>
5091
5092<!-- _______________________________________________________________________ -->
5093<div class="doc_subsubsection">
5094 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5095</div>
5096
5097<div class="doc_text">
5098
5099<h5>Syntax:</h5>
5100<pre>
5101 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5102</pre>
5103
5104<h5>Overview:</h5>
5105
5106<p>
5107The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5108target-specific value indicating the return address of the current function
5109or one of its callers.
5110</p>
5111
5112<h5>Arguments:</h5>
5113
5114<p>
5115The argument to this intrinsic indicates which function to return the address
5116for. Zero indicates the calling function, one indicates its caller, etc. The
5117argument is <b>required</b> to be a constant integer value.
5118</p>
5119
5120<h5>Semantics:</h5>
5121
5122<p>
5123The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5124the return address of the specified call frame, or zero if it cannot be
5125identified. The value returned by this intrinsic is likely to be incorrect or 0
5126for arguments other than zero, so it should only be used for debugging purposes.
5127</p>
5128
5129<p>
5130Note that calling this intrinsic does not prevent function inlining or other
5131aggressive transformations, so the value returned may not be that of the obvious
5132source-language caller.
5133</p>
5134</div>
5135
5136
5137<!-- _______________________________________________________________________ -->
5138<div class="doc_subsubsection">
5139 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5140</div>
5141
5142<div class="doc_text">
5143
5144<h5>Syntax:</h5>
5145<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5146 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5147</pre>
5148
5149<h5>Overview:</h5>
5150
5151<p>
5152The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5153target-specific frame pointer value for the specified stack frame.
5154</p>
5155
5156<h5>Arguments:</h5>
5157
5158<p>
5159The argument to this intrinsic indicates which function to return the frame
5160pointer for. Zero indicates the calling function, one indicates its caller,
5161etc. The argument is <b>required</b> to be a constant integer value.
5162</p>
5163
5164<h5>Semantics:</h5>
5165
5166<p>
5167The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5168the frame address of the specified call frame, or zero if it cannot be
5169identified. The value returned by this intrinsic is likely to be incorrect or 0
5170for arguments other than zero, so it should only be used for debugging purposes.
5171</p>
5172
5173<p>
5174Note that calling this intrinsic does not prevent function inlining or other
5175aggressive transformations, so the value returned may not be that of the obvious
5176source-language caller.
5177</p>
5178</div>
5179
5180<!-- _______________________________________________________________________ -->
5181<div class="doc_subsubsection">
5182 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5183</div>
5184
5185<div class="doc_text">
5186
5187<h5>Syntax:</h5>
5188<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5189 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190</pre>
5191
5192<h5>Overview:</h5>
5193
5194<p>
5195The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5196the function stack, for use with <a href="#int_stackrestore">
5197<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5198features like scoped automatic variable sized arrays in C99.
5199</p>
5200
5201<h5>Semantics:</h5>
5202
5203<p>
5204This intrinsic returns a opaque pointer value that can be passed to <a
5205href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5206<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5207<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5208state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5209practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5210that were allocated after the <tt>llvm.stacksave</tt> was executed.
5211</p>
5212
5213</div>
5214
5215<!-- _______________________________________________________________________ -->
5216<div class="doc_subsubsection">
5217 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5218</div>
5219
5220<div class="doc_text">
5221
5222<h5>Syntax:</h5>
5223<pre>
5224 declare void @llvm.stackrestore(i8 * %ptr)
5225</pre>
5226
5227<h5>Overview:</h5>
5228
5229<p>
5230The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5231the function stack to the state it was in when the corresponding <a
5232href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5233useful for implementing language features like scoped automatic variable sized
5234arrays in C99.
5235</p>
5236
5237<h5>Semantics:</h5>
5238
5239<p>
5240See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5241</p>
5242
5243</div>
5244
5245
5246<!-- _______________________________________________________________________ -->
5247<div class="doc_subsubsection">
5248 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5249</div>
5250
5251<div class="doc_text">
5252
5253<h5>Syntax:</h5>
5254<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5255 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]5256</pre>
5257
5258<h5>Overview:</h5>
5259
5260
5261<p>
5262The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5263a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5264no
5265effect on the behavior of the program but can change its performance
5266characteristics.
5267</p>
5268
5269<h5>Arguments:</h5>
5270
5271<p>
5272<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5273determining if the fetch should be for a read (0) or write (1), and
5274<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5275locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5276<tt>locality</tt> arguments must be constant integers.
5277</p>
5278
5279<h5>Semantics:</h5>
5280
5281<p>
5282This intrinsic does not modify the behavior of the program. In particular,
5283prefetches cannot trap and do not produce a value. On targets that support this
5284intrinsic, the prefetch can provide hints to the processor cache for better
5285performance.
5286</p>
5287
5288</div>
5289
5290<!-- _______________________________________________________________________ -->
5291<div class="doc_subsubsection">
5292 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5293</div>
5294
5295<div class="doc_text">
5296
5297<h5>Syntax:</h5>
5298<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5299 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5300</pre>
5301
5302<h5>Overview:</h5>
5303
5304
5305<p>
5306The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5307(PC) in a region of
5308code to simulators and other tools. The method is target specific, but it is
5309expected that the marker will use exported symbols to transmit the PC of the
5310marker.
5311The marker makes no guarantees that it will remain with any specific instruction
5312after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5313optimizations. The intended use is to be inserted after optimizations to allow
5314correlations of simulation runs.
5315</p>
5316
5317<h5>Arguments:</h5>
5318
5319<p>
5320<tt>id</tt> is a numerical id identifying the marker.
5321</p>
5322
5323<h5>Semantics:</h5>
5324
5325<p>
5326This intrinsic does not modify the behavior of the program. Backends that do not
5327support this intrinisic may ignore it.
5328</p>
5329
5330</div>
5331
5332<!-- _______________________________________________________________________ -->
5333<div class="doc_subsubsection">
5334 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5335</div>
5336
5337<div class="doc_text">
5338
5339<h5>Syntax:</h5>
5340<pre>
5341 declare i64 @llvm.readcyclecounter( )
5342</pre>
5343
5344<h5>Overview:</h5>
5345
5346
5347<p>
5348The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5349counter register (or similar low latency, high accuracy clocks) on those targets
5350that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5351As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5352should only be used for small timings.
5353</p>
5354
5355<h5>Semantics:</h5>
5356
5357<p>
5358When directly supported, reading the cycle counter should not modify any memory.
5359Implementations are allowed to either return a application specific value or a
5360system wide value. On backends without support, this is lowered to a constant 0.
5361</p>
5362
5363</div>
5364
5365<!-- ======================================================================= -->
5366<div class="doc_subsection">
5367 <a name="int_libc">Standard C Library Intrinsics</a>
5368</div>
5369
5370<div class="doc_text">
5371<p>
5372LLVM provides intrinsics for a few important standard C library functions.
5373These intrinsics allow source-language front-ends to pass information about the
5374alignment of the pointer arguments to the code generator, providing opportunity
5375for more efficient code generation.
5376</p>
5377
5378</div>
5379
5380<!-- _______________________________________________________________________ -->
5381<div class="doc_subsubsection">
5382 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5383</div>
5384
5385<div class="doc_text">
5386
5387<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5388<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5389width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5390<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5391 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5392 i8 &lt;len&gt;, i32 &lt;align&gt;)
5393 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5394 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5396 i32 &lt;len&gt;, i32 &lt;align&gt;)
5397 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5398 i64 &lt;len&gt;, i32 &lt;align&gt;)
5399</pre>
5400
5401<h5>Overview:</h5>
5402
5403<p>
5404The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5405location to the destination location.
5406</p>
5407
5408<p>
5409Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5410intrinsics do not return a value, and takes an extra alignment argument.
5411</p>
5412
5413<h5>Arguments:</h5>
5414
5415<p>
5416The first argument is a pointer to the destination, the second is a pointer to
5417the source. The third argument is an integer argument
5418specifying the number of bytes to copy, and the fourth argument is the alignment
5419of the source and destination locations.
5420</p>
5421
5422<p>
5423If the call to this intrinisic has an alignment value that is not 0 or 1, then
5424the caller guarantees that both the source and destination pointers are aligned
5425to that boundary.
5426</p>
5427
5428<h5>Semantics:</h5>
5429
5430<p>
5431The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5432location to the destination location, which are not allowed to overlap. It
5433copies "len" bytes of memory over. If the argument is known to be aligned to
5434some boundary, this can be specified as the fourth argument, otherwise it should
5435be set to 0 or 1.
5436</p>
5437</div>
5438
5439
5440<!-- _______________________________________________________________________ -->
5441<div class="doc_subsubsection">
5442 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5443</div>
5444
5445<div class="doc_text">
5446
5447<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5448<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5449width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5450<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5451 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5452 i8 &lt;len&gt;, i32 &lt;align&gt;)
5453 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5454 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5456 i32 &lt;len&gt;, i32 &lt;align&gt;)
5457 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5458 i64 &lt;len&gt;, i32 &lt;align&gt;)
5459</pre>
5460
5461<h5>Overview:</h5>
5462
5463<p>
5464The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5465location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5466'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467</p>
5468
5469<p>
5470Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5471intrinsics do not return a value, and takes an extra alignment argument.
5472</p>
5473
5474<h5>Arguments:</h5>
5475
5476<p>
5477The first argument is a pointer to the destination, the second is a pointer to
5478the source. The third argument is an integer argument
5479specifying the number of bytes to copy, and the fourth argument is the alignment
5480of the source and destination locations.
5481</p>
5482
5483<p>
5484If the call to this intrinisic has an alignment value that is not 0 or 1, then
5485the caller guarantees that the source and destination pointers are aligned to
5486that boundary.
5487</p>
5488
5489<h5>Semantics:</h5>
5490
5491<p>
5492The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5493location to the destination location, which may overlap. It
5494copies "len" bytes of memory over. If the argument is known to be aligned to
5495some boundary, this can be specified as the fourth argument, otherwise it should
5496be set to 0 or 1.
5497</p>
5498</div>
5499
5500
5501<!-- _______________________________________________________________________ -->
5502<div class="doc_subsubsection">
5503 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5504</div>
5505
5506<div class="doc_text">
5507
5508<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5509<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5510width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5511<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5512 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5513 i8 &lt;len&gt;, i32 &lt;align&gt;)
5514 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5515 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5516 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5517 i32 &lt;len&gt;, i32 &lt;align&gt;)
5518 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5519 i64 &lt;len&gt;, i32 &lt;align&gt;)
5520</pre>
5521
5522<h5>Overview:</h5>
5523
5524<p>
5525The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5526byte value.
5527</p>
5528
5529<p>
5530Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5531does not return a value, and takes an extra alignment argument.
5532</p>
5533
5534<h5>Arguments:</h5>
5535
5536<p>
5537The first argument is a pointer to the destination to fill, the second is the
5538byte value to fill it with, the third argument is an integer
5539argument specifying the number of bytes to fill, and the fourth argument is the
5540known alignment of destination location.
5541</p>
5542
5543<p>
5544If the call to this intrinisic has an alignment value that is not 0 or 1, then
5545the caller guarantees that the destination pointer is aligned to that boundary.
5546</p>
5547
5548<h5>Semantics:</h5>
5549
5550<p>
5551The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5552the
5553destination location. If the argument is known to be aligned to some boundary,
5554this can be specified as the fourth argument, otherwise it should be set to 0 or
55551.
5556</p>
5557</div>
5558
5559
5560<!-- _______________________________________________________________________ -->
5561<div class="doc_subsubsection">
5562 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5563</div>
5564
5565<div class="doc_text">
5566
5567<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5568<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]5569floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5570types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5571<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5572 declare float @llvm.sqrt.f32(float %Val)
5573 declare double @llvm.sqrt.f64(double %Val)
5574 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5575 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5576 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5577</pre>
5578
5579<h5>Overview:</h5>
5580
5581<p>
5582The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5583returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5584<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5585negative numbers other than -0.0 (which allows for better optimization, because
5586there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5587defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5588</p>
5589
5590<h5>Arguments:</h5>
5591
5592<p>
5593The argument and return value are floating point numbers of the same type.
5594</p>
5595
5596<h5>Semantics:</h5>
5597
5598<p>
5599This function returns the sqrt of the specified operand if it is a nonnegative
5600floating point number.
5601</p>
5602</div>
5603
5604<!-- _______________________________________________________________________ -->
5605<div class="doc_subsubsection">
5606 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5607</div>
5608
5609<div class="doc_text">
5610
5611<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5612<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]5613floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5614types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5615<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5616 declare float @llvm.powi.f32(float %Val, i32 %power)
5617 declare double @llvm.powi.f64(double %Val, i32 %power)
5618 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5619 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5620 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5621</pre>
5622
5623<h5>Overview:</h5>
5624
5625<p>
5626The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5627specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5628multiplications is not defined. When a vector of floating point type is
5629used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5630</p>
5631
5632<h5>Arguments:</h5>
5633
5634<p>
5635The second argument is an integer power, and the first is a value to raise to
5636that power.
5637</p>
5638
5639<h5>Semantics:</h5>
5640
5641<p>
5642This function returns the first value raised to the second power with an
5643unspecified sequence of rounding operations.</p>
5644</div>
5645
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5646<!-- _______________________________________________________________________ -->
5647<div class="doc_subsubsection">
5648 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5649</div>
5650
5651<div class="doc_text">
5652
5653<h5>Syntax:</h5>
5654<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5655floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5656types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5657<pre>
5658 declare float @llvm.sin.f32(float %Val)
5659 declare double @llvm.sin.f64(double %Val)
5660 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5661 declare fp128 @llvm.sin.f128(fp128 %Val)
5662 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5663</pre>
5664
5665<h5>Overview:</h5>
5666
5667<p>
5668The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5669</p>
5670
5671<h5>Arguments:</h5>
5672
5673<p>
5674The argument and return value are floating point numbers of the same type.
5675</p>
5676
5677<h5>Semantics:</h5>
5678
5679<p>
5680This function returns the sine of the specified operand, returning the
5681same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5682conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5683</div>
5684
5685<!-- _______________________________________________________________________ -->
5686<div class="doc_subsubsection">
5687 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5688</div>
5689
5690<div class="doc_text">
5691
5692<h5>Syntax:</h5>
5693<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5694floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5695types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5696<pre>
5697 declare float @llvm.cos.f32(float %Val)
5698 declare double @llvm.cos.f64(double %Val)
5699 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5700 declare fp128 @llvm.cos.f128(fp128 %Val)
5701 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5702</pre>
5703
5704<h5>Overview:</h5>
5705
5706<p>
5707The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5708</p>
5709
5710<h5>Arguments:</h5>
5711
5712<p>
5713The argument and return value are floating point numbers of the same type.
5714</p>
5715
5716<h5>Semantics:</h5>
5717
5718<p>
5719This function returns the cosine of the specified operand, returning the
5720same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5721conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5722</div>
5723
5724<!-- _______________________________________________________________________ -->
5725<div class="doc_subsubsection">
5726 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5727</div>
5728
5729<div class="doc_text">
5730
5731<h5>Syntax:</h5>
5732<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5733floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5734types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5735<pre>
5736 declare float @llvm.pow.f32(float %Val, float %Power)
5737 declare double @llvm.pow.f64(double %Val, double %Power)
5738 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5739 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5740 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5741</pre>
5742
5743<h5>Overview:</h5>
5744
5745<p>
5746The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5747specified (positive or negative) power.
5748</p>
5749
5750<h5>Arguments:</h5>
5751
5752<p>
5753The second argument is a floating point power, and the first is a value to
5754raise to that power.
5755</p>
5756
5757<h5>Semantics:</h5>
5758
5759<p>
5760This function returns the first value raised to the second power,
5761returning the
5762same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5763conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5764</div>
5765
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5766
5767<!-- ======================================================================= -->
5768<div class="doc_subsection">
5769 <a name="int_manip">Bit Manipulation Intrinsics</a>
5770</div>
5771
5772<div class="doc_text">
5773<p>
5774LLVM provides intrinsics for a few important bit manipulation operations.
5775These allow efficient code generation for some algorithms.
5776</p>
5777
5778</div>
5779
5780<!-- _______________________________________________________________________ -->
5781<div class="doc_subsubsection">
5782 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5783</div>
5784
5785<div class="doc_text">
5786
5787<h5>Syntax:</h5>
5788<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5789type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5790<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5791 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5792 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5793 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5794</pre>
5795
5796<h5>Overview:</h5>
5797
5798<p>
5799The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5800values with an even number of bytes (positive multiple of 16 bits). These are
5801useful for performing operations on data that is not in the target's native
5802byte order.
5803</p>
5804
5805<h5>Semantics:</h5>
5806
5807<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5808The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5809and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5810intrinsic returns an i32 value that has the four bytes of the input i32
5811swapped, 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]5812i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5813<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5814additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5815</p>
5816
5817</div>
5818
5819<!-- _______________________________________________________________________ -->
5820<div class="doc_subsubsection">
5821 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5822</div>
5823
5824<div class="doc_text">
5825
5826<h5>Syntax:</h5>
5827<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]5828width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5829<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5830 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5831 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5832 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5833 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5834 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5835</pre>
5836
5837<h5>Overview:</h5>
5838
5839<p>
5840The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5841value.
5842</p>
5843
5844<h5>Arguments:</h5>
5845
5846<p>
5847The only argument is the value to be counted. The argument may be of any
5848integer type. The return type must match the argument type.
5849</p>
5850
5851<h5>Semantics:</h5>
5852
5853<p>
5854The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5855</p>
5856</div>
5857
5858<!-- _______________________________________________________________________ -->
5859<div class="doc_subsubsection">
5860 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5861</div>
5862
5863<div class="doc_text">
5864
5865<h5>Syntax:</h5>
5866<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]5867integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5868<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5869 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5870 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5871 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5872 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5873 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5874</pre>
5875
5876<h5>Overview:</h5>
5877
5878<p>
5879The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5880leading zeros in a variable.
5881</p>
5882
5883<h5>Arguments:</h5>
5884
5885<p>
5886The only argument is the value to be counted. The argument may be of any
5887integer type. The return type must match the argument type.
5888</p>
5889
5890<h5>Semantics:</h5>
5891
5892<p>
5893The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5894in a variable. If the src == 0 then the result is the size in bits of the type
5895of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5896</p>
5897</div>
5898
5899
5900
5901<!-- _______________________________________________________________________ -->
5902<div class="doc_subsubsection">
5903 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5904</div>
5905
5906<div class="doc_text">
5907
5908<h5>Syntax:</h5>
5909<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]5910integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5911<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5912 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5913 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5914 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5915 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5916 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5917</pre>
5918
5919<h5>Overview:</h5>
5920
5921<p>
5922The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5923trailing zeros.
5924</p>
5925
5926<h5>Arguments:</h5>
5927
5928<p>
5929The only argument is the value to be counted. The argument may be of any
5930integer type. The return type must match the argument type.
5931</p>
5932
5933<h5>Semantics:</h5>
5934
5935<p>
5936The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5937in a variable. If the src == 0 then the result is the size in bits of the type
5938of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5939</p>
5940</div>
5941
5942<!-- _______________________________________________________________________ -->
5943<div class="doc_subsubsection">
5944 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5945</div>
5946
5947<div class="doc_text">
5948
5949<h5>Syntax:</h5>
5950<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5951on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5952<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5953 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5954 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5955</pre>
5956
5957<h5>Overview:</h5>
5958<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5959range of bits from an integer value and returns them in the same bit width as
5960the original value.</p>
5961
5962<h5>Arguments:</h5>
5963<p>The first argument, <tt>%val</tt> and the result may be integer types of
5964any bit width but they must have the same bit width. The second and third
5965arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5966
5967<h5>Semantics:</h5>
5968<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5969of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5970<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5971operates in forward mode.</p>
5972<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5973right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5974only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5975<ol>
5976 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5977 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5978 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5979 to determine the number of bits to retain.</li>
5980 <li>A mask of the retained bits is created by shifting a -1 value.</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5981 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5982</ol>
5983<p>In reverse mode, a similar computation is made except that the bits are
5984returned in the reverse order. So, for example, if <tt>X</tt> has the value
5985<tt>i16 0x0ACF (101011001111)</tt> and we apply
5986<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5987<tt>i16 0x0026 (000000100110)</tt>.</p>
5988</div>
5989
5990<div class="doc_subsubsection">
5991 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5992</div>
5993
5994<div class="doc_text">
5995
5996<h5>Syntax:</h5>
5997<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5998on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5999<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6000 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
6001 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6002</pre>
6003
6004<h5>Overview:</h5>
6005<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
6006of bits in an integer value with another integer value. It returns the integer
6007with the replaced bits.</p>
6008
6009<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6010<p>The first argument, <tt>%val</tt>, and the result may be integer types of
6011any bit width, but they must have the same bit width. <tt>%val</tt> is the value
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6012whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
6013integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
6014type since they specify only a bit index.</p>
6015
6016<h5>Semantics:</h5>
6017<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
6018of operation: forwards and reverse. If <tt>%lo</tt> is greater than
6019<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
6020operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6021
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6022<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
6023truncating it down to the size of the replacement area or zero extending it
6024up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6025
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6026<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
6027are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
6028in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6029to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6030
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6031<p>In reverse mode, a similar computation is made except that the bits are
6032reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6033<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6034
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6035<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6036
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6037<pre>
6038 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
6039 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
6040 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
6041 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
6042 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
6043</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6044
6045</div>
6046
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6047<!-- ======================================================================= -->
6048<div class="doc_subsection">
6049 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6050</div>
6051
6052<div class="doc_text">
6053<p>
6054LLVM provides intrinsics for some arithmetic with overflow operations.
6055</p>
6056
6057</div>
6058
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6059<!-- _______________________________________________________________________ -->
6060<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6061 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6062</div>
6063
6064<div class="doc_text">
6065
6066<h5>Syntax:</h5>
6067
6068<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]6069on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6070
6071<pre>
6072 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6073 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6074 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6075</pre>
6076
6077<h5>Overview:</h5>
6078
6079<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6080a signed addition of the two arguments, and indicate whether an overflow
6081occurred during the signed summation.</p>
6082
6083<h5>Arguments:</h5>
6084
6085<p>The arguments (%a and %b) and the first element of the result structure may
6086be of integer types of any bit width, but they must have the same bit width. The
6087second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6088and <tt>%b</tt> are the two values that will undergo signed addition.</p>
6089
6090<h5>Semantics:</h5>
6091
6092<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6093a signed addition of the two variables. They return a structure &mdash; the
6094first element of which is the signed summation, and the second element of which
6095is a bit specifying if the signed summation resulted in an overflow.</p>
6096
6097<h5>Examples:</h5>
6098<pre>
6099 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6100 %sum = extractvalue {i32, i1} %res, 0
6101 %obit = extractvalue {i32, i1} %res, 1
6102 br i1 %obit, label %overflow, label %normal
6103</pre>
6104
6105</div>
6106
6107<!-- _______________________________________________________________________ -->
6108<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6109 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6110</div>
6111
6112<div class="doc_text">
6113
6114<h5>Syntax:</h5>
6115
6116<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]6117on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6118
6119<pre>
6120 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6121 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6122 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6123</pre>
6124
6125<h5>Overview:</h5>
6126
6127<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6128an unsigned addition of the two arguments, and indicate whether a carry occurred
6129during the unsigned summation.</p>
6130
6131<h5>Arguments:</h5>
6132
6133<p>The arguments (%a and %b) and the first element of the result structure may
6134be of integer types of any bit width, but they must have the same bit width. The
6135second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6136and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6137
6138<h5>Semantics:</h5>
6139
6140<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6141an unsigned addition of the two arguments. They return a structure &mdash; the
6142first element of which is the sum, and the second element of which is a bit
6143specifying if the unsigned summation resulted in a carry.</p>
6144
6145<h5>Examples:</h5>
6146<pre>
6147 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6148 %sum = extractvalue {i32, i1} %res, 0
6149 %obit = extractvalue {i32, i1} %res, 1
6150 br i1 %obit, label %carry, label %normal
6151</pre>
6152
6153</div>
6154
6155<!-- _______________________________________________________________________ -->
6156<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6157 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6158</div>
6159
6160<div class="doc_text">
6161
6162<h5>Syntax:</h5>
6163
6164<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]6165on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6166
6167<pre>
6168 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6169 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6170 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6171</pre>
6172
6173<h5>Overview:</h5>
6174
6175<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6176a signed subtraction of the two arguments, and indicate whether an overflow
6177occurred during the signed subtraction.</p>
6178
6179<h5>Arguments:</h5>
6180
6181<p>The arguments (%a and %b) and the first element of the result structure may
6182be of integer types of any bit width, but they must have the same bit width. The
6183second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6184and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6185
6186<h5>Semantics:</h5>
6187
6188<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6189a signed subtraction of the two arguments. They return a structure &mdash; the
6190first element of which is the subtraction, and the second element of which is a bit
6191specifying if the signed subtraction resulted in an overflow.</p>
6192
6193<h5>Examples:</h5>
6194<pre>
6195 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6196 %sum = extractvalue {i32, i1} %res, 0
6197 %obit = extractvalue {i32, i1} %res, 1
6198 br i1 %obit, label %overflow, label %normal
6199</pre>
6200
6201</div>
6202
6203<!-- _______________________________________________________________________ -->
6204<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6205 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6206</div>
6207
6208<div class="doc_text">
6209
6210<h5>Syntax:</h5>
6211
6212<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]6213on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6214
6215<pre>
6216 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6217 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6218 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6219</pre>
6220
6221<h5>Overview:</h5>
6222
6223<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6224an unsigned subtraction of the two arguments, and indicate whether an overflow
6225occurred during the unsigned subtraction.</p>
6226
6227<h5>Arguments:</h5>
6228
6229<p>The arguments (%a and %b) and the first element of the result structure may
6230be of integer types of any bit width, but they must have the same bit width. The
6231second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6232and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6233
6234<h5>Semantics:</h5>
6235
6236<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6237an unsigned subtraction of the two arguments. They return a structure &mdash; the
6238first element of which is the subtraction, and the second element of which is a bit
6239specifying if the unsigned subtraction resulted in an overflow.</p>
6240
6241<h5>Examples:</h5>
6242<pre>
6243 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6244 %sum = extractvalue {i32, i1} %res, 0
6245 %obit = extractvalue {i32, i1} %res, 1
6246 br i1 %obit, label %overflow, label %normal
6247</pre>
6248
6249</div>
6250
6251<!-- _______________________________________________________________________ -->
6252<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6253 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6254</div>
6255
6256<div class="doc_text">
6257
6258<h5>Syntax:</h5>
6259
6260<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]6261on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6262
6263<pre>
6264 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6265 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6266 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6267</pre>
6268
6269<h5>Overview:</h5>
6270
6271<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6272a signed multiplication of the two arguments, and indicate whether an overflow
6273occurred during the signed multiplication.</p>
6274
6275<h5>Arguments:</h5>
6276
6277<p>The arguments (%a and %b) and the first element of the result structure may
6278be of integer types of any bit width, but they must have the same bit width. The
6279second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6280and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6281
6282<h5>Semantics:</h5>
6283
6284<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6285a signed multiplication of the two arguments. They return a structure &mdash;
6286the first element of which is the multiplication, and the second element of
6287which is a bit specifying if the signed multiplication resulted in an
6288overflow.</p>
6289
6290<h5>Examples:</h5>
6291<pre>
6292 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6293 %sum = extractvalue {i32, i1} %res, 0
6294 %obit = extractvalue {i32, i1} %res, 1
6295 br i1 %obit, label %overflow, label %normal
6296</pre>
6297
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6298</div>
6299
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6300<!-- _______________________________________________________________________ -->
6301<div class="doc_subsubsection">
6302 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6303</div>
6304
6305<div class="doc_text">
6306
6307<h5>Syntax:</h5>
6308
6309<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6310on any integer bit width.</p>
6311
6312<pre>
6313 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6314 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6315 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6316</pre>
6317
6318<h5>Overview:</h5>
6319
6320<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6321actively being fixed, but it should not currently be used!</i></p>
6322
6323<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6324a unsigned multiplication of the two arguments, and indicate whether an overflow
6325occurred during the unsigned multiplication.</p>
6326
6327<h5>Arguments:</h5>
6328
6329<p>The arguments (%a and %b) and the first element of the result structure may
6330be of integer types of any bit width, but they must have the same bit width. The
6331second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6332and <tt>%b</tt> are the two values that will undergo unsigned
6333multiplication.</p>
6334
6335<h5>Semantics:</h5>
6336
6337<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6338an unsigned multiplication of the two arguments. They return a structure &mdash;
6339the first element of which is the multiplication, and the second element of
6340which is a bit specifying if the unsigned multiplication resulted in an
6341overflow.</p>
6342
6343<h5>Examples:</h5>
6344<pre>
6345 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6346 %sum = extractvalue {i32, i1} %res, 0
6347 %obit = extractvalue {i32, i1} %res, 1
6348 br i1 %obit, label %overflow, label %normal
6349</pre>
6350
6351</div>
6352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6353<!-- ======================================================================= -->
6354<div class="doc_subsection">
6355 <a name="int_debugger">Debugger Intrinsics</a>
6356</div>
6357
6358<div class="doc_text">
6359<p>
6360The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6361are described in the <a
6362href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6363Debugging</a> document.
6364</p>
6365</div>
6366
6367
6368<!-- ======================================================================= -->
6369<div class="doc_subsection">
6370 <a name="int_eh">Exception Handling Intrinsics</a>
6371</div>
6372
6373<div class="doc_text">
6374<p> The LLVM exception handling intrinsics (which all start with
6375<tt>llvm.eh.</tt> prefix), are described in the <a
6376href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6377Handling</a> document. </p>
6378</div>
6379
6380<!-- ======================================================================= -->
6381<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6382 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6383</div>
6384
6385<div class="doc_text">
6386<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6387 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6388 the <tt>nest</tt> attribute, from a function. The result is a callable
6389 function pointer lacking the nest parameter - the caller does not need
6390 to provide a value for it. Instead, the value to use is stored in
6391 advance in a "trampoline", a block of memory usually allocated
6392 on the stack, which also contains code to splice the nest value into the
6393 argument list. This is used to implement the GCC nested function address
6394 extension.
6395</p>
6396<p>
6397 For example, if the function is
6398 <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]6399 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]6400<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6401 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6402 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6403 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6404 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6405</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6406 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6407 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6408</div>
6409
6410<!-- _______________________________________________________________________ -->
6411<div class="doc_subsubsection">
6412 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6413</div>
6414<div class="doc_text">
6415<h5>Syntax:</h5>
6416<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6417declare 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]6418</pre>
6419<h5>Overview:</h5>
6420<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6421 This fills the memory pointed to by <tt>tramp</tt> with code
6422 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6423</p>
6424<h5>Arguments:</h5>
6425<p>
6426 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6427 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6428 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6429 intrinsic. Note that the size and the alignment are target-specific - LLVM
6430 currently provides no portable way of determining them, so a front-end that
6431 generates this intrinsic needs to have some target-specific knowledge.
6432 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]6433</p>
6434<h5>Semantics:</h5>
6435<p>
6436 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6437 dependent code, turning it into a function. A pointer to this function is
6438 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6439 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6440 before being called. The new function's signature is the same as that of
6441 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6442 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6443 of pointer type. Calling the new function is equivalent to calling
6444 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6445 missing <tt>nest</tt> argument. If, after calling
6446 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6447 modified, then the effect of any later call to the returned function pointer is
6448 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6449</p>
6450</div>
6451
6452<!-- ======================================================================= -->
6453<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6454 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6455</div>
6456
6457<div class="doc_text">
6458<p>
6459 These intrinsic functions expand the "universal IR" of LLVM to represent
6460 hardware constructs for atomic operations and memory synchronization. This
6461 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6462 is aimed at a low enough level to allow any programming models or APIs
6463 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6464 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6465 hardware behavior. Just as hardware provides a "universal IR" for source
6466 languages, it also provides a starting point for developing a "universal"
6467 atomic operation and synchronization IR.
6468</p>
6469<p>
6470 These do <em>not</em> form an API such as high-level threading libraries,
6471 software transaction memory systems, atomic primitives, and intrinsic
6472 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6473 application libraries. The hardware interface provided by LLVM should allow
6474 a clean implementation of all of these APIs and parallel programming models.
6475 No one model or paradigm should be selected above others unless the hardware
6476 itself ubiquitously does so.
6477
6478</p>
6479</div>
6480
6481<!-- _______________________________________________________________________ -->
6482<div class="doc_subsubsection">
6483 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6484</div>
6485<div class="doc_text">
6486<h5>Syntax:</h5>
6487<pre>
6488declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6489i1 &lt;device&gt; )
6490
6491</pre>
6492<h5>Overview:</h5>
6493<p>
6494 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6495 specific pairs of memory access types.
6496</p>
6497<h5>Arguments:</h5>
6498<p>
6499 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6500 The first four arguments enables a specific barrier as listed below. The fith
6501 argument specifies that the barrier applies to io or device or uncached memory.
6502
6503</p>
6504 <ul>
6505 <li><tt>ll</tt>: load-load barrier</li>
6506 <li><tt>ls</tt>: load-store barrier</li>
6507 <li><tt>sl</tt>: store-load barrier</li>
6508 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6509 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6510 </ul>
6511<h5>Semantics:</h5>
6512<p>
6513 This intrinsic causes the system to enforce some ordering constraints upon
6514 the loads and stores of the program. This barrier does not indicate
6515 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6516 which they occur. For any of the specified pairs of load and store operations
6517 (f.ex. load-load, or store-load), all of the first operations preceding the
6518 barrier will complete before any of the second operations succeeding the
6519 barrier begin. Specifically the semantics for each pairing is as follows:
6520</p>
6521 <ul>
6522 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6523 after the barrier begins.</li>
6524
6525 <li><tt>ls</tt>: All loads before the barrier must complete before any
6526 store after the barrier begins.</li>
6527 <li><tt>ss</tt>: All stores before the barrier must complete before any
6528 store after the barrier begins.</li>
6529 <li><tt>sl</tt>: All stores before the barrier must complete before any
6530 load after the barrier begins.</li>
6531 </ul>
6532<p>
6533 These semantics are applied with a logical "and" behavior when more than one
6534 is enabled in a single memory barrier intrinsic.
6535</p>
6536<p>
6537 Backends may implement stronger barriers than those requested when they do not
6538 support as fine grained a barrier as requested. Some architectures do not
6539 need all types of barriers and on such architectures, these become noops.
6540</p>
6541<h5>Example:</h5>
6542<pre>
6543%ptr = malloc i32
6544 store i32 4, %ptr
6545
6546%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6547 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6548 <i>; guarantee the above finishes</i>
6549 store i32 8, %ptr <i>; before this begins</i>
6550</pre>
6551</div>
6552
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6553<!-- _______________________________________________________________________ -->
6554<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6555 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6556</div>
6557<div class="doc_text">
6558<h5>Syntax:</h5>
6559<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6560 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6561 any integer bit width and for different address spaces. Not all targets
6562 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6563
6564<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6565declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6566declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6567declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6568declare 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]6569
6570</pre>
6571<h5>Overview:</h5>
6572<p>
6573 This loads a value in memory and compares it to a given value. If they are
6574 equal, it stores a new value into the memory.
6575</p>
6576<h5>Arguments:</h5>
6577<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6578 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6579 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6580 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6581 this integer type. While any bit width integer may be used, targets may only
6582 lower representations they support in hardware.
6583
6584</p>
6585<h5>Semantics:</h5>
6586<p>
6587 This entire intrinsic must be executed atomically. It first loads the value
6588 in memory pointed to by <tt>ptr</tt> and compares it with the value
6589 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6590 loaded value is yielded in all cases. This provides the equivalent of an
6591 atomic compare-and-swap operation within the SSA framework.
6592</p>
6593<h5>Examples:</h5>
6594
6595<pre>
6596%ptr = malloc i32
6597 store i32 4, %ptr
6598
6599%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6600%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6601 <i>; yields {i32}:result1 = 4</i>
6602%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6603%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6604
6605%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6606%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6607 <i>; yields {i32}:result2 = 8</i>
6608%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6609
6610%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6611</pre>
6612</div>
6613
6614<!-- _______________________________________________________________________ -->
6615<div class="doc_subsubsection">
6616 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6617</div>
6618<div class="doc_text">
6619<h5>Syntax:</h5>
6620
6621<p>
6622 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6623 integer bit width. Not all targets support all bit widths however.</p>
6624<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6625declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6626declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6627declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6628declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6629
6630</pre>
6631<h5>Overview:</h5>
6632<p>
6633 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6634 the value from memory. It then stores the value in <tt>val</tt> in the memory
6635 at <tt>ptr</tt>.
6636</p>
6637<h5>Arguments:</h5>
6638
6639<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6640 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6641 <tt>val</tt> argument and the result must be integers of the same bit width.
6642 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6643 integer type. The targets may only lower integer representations they
6644 support.
6645</p>
6646<h5>Semantics:</h5>
6647<p>
6648 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6649 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6650 equivalent of an atomic swap operation within the SSA framework.
6651
6652</p>
6653<h5>Examples:</h5>
6654<pre>
6655%ptr = malloc i32
6656 store i32 4, %ptr
6657
6658%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6659%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6660 <i>; yields {i32}:result1 = 4</i>
6661%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6662%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6663
6664%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6665%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6666 <i>; yields {i32}:result2 = 8</i>
6667
6668%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6669%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6670</pre>
6671</div>
6672
6673<!-- _______________________________________________________________________ -->
6674<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6675 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6676
6677</div>
6678<div class="doc_text">
6679<h5>Syntax:</h5>
6680<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6681 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]6682 integer bit width. Not all targets support all bit widths however.</p>
6683<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6684declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6685declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6686declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6687declare 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]6688
6689</pre>
6690<h5>Overview:</h5>
6691<p>
6692 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6693 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6694</p>
6695<h5>Arguments:</h5>
6696<p>
6697
6698 The intrinsic takes two arguments, the first a pointer to an integer value
6699 and the second an integer value. The result is also an integer value. These
6700 integer types can have any bit width, but they must all have the same bit
6701 width. The targets may only lower integer representations they support.
6702</p>
6703<h5>Semantics:</h5>
6704<p>
6705 This intrinsic does a series of operations atomically. It first loads the
6706 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6707 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6708</p>
6709
6710<h5>Examples:</h5>
6711<pre>
6712%ptr = malloc i32
6713 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6714%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6715 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6716%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6717 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6718%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6719 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6720%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6721</pre>
6722</div>
6723
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6724<!-- _______________________________________________________________________ -->
6725<div class="doc_subsubsection">
6726 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6727
6728</div>
6729<div class="doc_text">
6730<h5>Syntax:</h5>
6731<p>
6732 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]6733 any integer bit width and for different address spaces. Not all targets
6734 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6735<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6736declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6737declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6738declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6739declare 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]6740
6741</pre>
6742<h5>Overview:</h5>
6743<p>
6744 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6745 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6746</p>
6747<h5>Arguments:</h5>
6748<p>
6749
6750 The intrinsic takes two arguments, the first a pointer to an integer value
6751 and the second an integer value. The result is also an integer value. These
6752 integer types can have any bit width, but they must all have the same bit
6753 width. The targets may only lower integer representations they support.
6754</p>
6755<h5>Semantics:</h5>
6756<p>
6757 This intrinsic does a series of operations atomically. It first loads the
6758 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6759 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6760</p>
6761
6762<h5>Examples:</h5>
6763<pre>
6764%ptr = malloc i32
6765 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6766%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6767 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6768%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6769 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6770%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6771 <i>; yields {i32}:result3 = 2</i>
6772%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6773</pre>
6774</div>
6775
6776<!-- _______________________________________________________________________ -->
6777<div class="doc_subsubsection">
6778 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6779 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6780 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6781 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6782
6783</div>
6784<div class="doc_text">
6785<h5>Syntax:</h5>
6786<p>
6787 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6788 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6789 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6790 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6791<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6792declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6793declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6794declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6795declare 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]6796
6797</pre>
6798
6799<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6800declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6801declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6802declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6803declare 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]6804
6805</pre>
6806
6807<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6808declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6809declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6810declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6811declare 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]6812
6813</pre>
6814
6815<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6816declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6817declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6818declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6819declare 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]6820
6821</pre>
6822<h5>Overview:</h5>
6823<p>
6824 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6825 the value stored in memory at <tt>ptr</tt>. It yields the original value
6826 at <tt>ptr</tt>.
6827</p>
6828<h5>Arguments:</h5>
6829<p>
6830
6831 These intrinsics take two arguments, the first a pointer to an integer value
6832 and the second an integer value. The result is also an integer value. These
6833 integer types can have any bit width, but they must all have the same bit
6834 width. The targets may only lower integer representations they support.
6835</p>
6836<h5>Semantics:</h5>
6837<p>
6838 These intrinsics does a series of operations atomically. They first load the
6839 value stored at <tt>ptr</tt>. They then do the bitwise operation
6840 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6841 value stored at <tt>ptr</tt>.
6842</p>
6843
6844<h5>Examples:</h5>
6845<pre>
6846%ptr = malloc i32
6847 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6848%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6849 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6850%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6851 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6852%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6853 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6854%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6855 <i>; yields {i32}:result3 = FF</i>
6856%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6857</pre>
6858</div>
6859
6860
6861<!-- _______________________________________________________________________ -->
6862<div class="doc_subsubsection">
6863 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6864 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6865 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6866 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6867
6868</div>
6869<div class="doc_text">
6870<h5>Syntax:</h5>
6871<p>
6872 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6873 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6874 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6875 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6876 support all bit widths however.</p>
6877<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6878declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6879declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6880declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6881declare 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]6882
6883</pre>
6884
6885<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6886declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6887declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6888declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6889declare 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]6890
6891</pre>
6892
6893<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6894declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6895declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6896declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6897declare 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]6898
6899</pre>
6900
6901<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6902declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6903declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6904declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6905declare 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]6906
6907</pre>
6908<h5>Overview:</h5>
6909<p>
6910 These intrinsics takes the signed or unsigned minimum or maximum of
6911 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6912 original value at <tt>ptr</tt>.
6913</p>
6914<h5>Arguments:</h5>
6915<p>
6916
6917 These intrinsics take two arguments, the first a pointer to an integer value
6918 and the second an integer value. The result is also an integer value. These
6919 integer types can have any bit width, but they must all have the same bit
6920 width. The targets may only lower integer representations they support.
6921</p>
6922<h5>Semantics:</h5>
6923<p>
6924 These intrinsics does a series of operations atomically. They first load the
6925 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6926 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6927 the original value stored at <tt>ptr</tt>.
6928</p>
6929
6930<h5>Examples:</h5>
6931<pre>
6932%ptr = malloc i32
6933 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6934%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6935 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6936%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6937 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6938%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6939 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6940%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6941 <i>; yields {i32}:result3 = 8</i>
6942%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6943</pre>
6944</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6945
6946<!-- ======================================================================= -->
6947<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6948 <a name="int_general">General Intrinsics</a>
6949</div>
6950
6951<div class="doc_text">
6952<p> This class of intrinsics is designed to be generic and has
6953no specific purpose. </p>
6954</div>
6955
6956<!-- _______________________________________________________________________ -->
6957<div class="doc_subsubsection">
6958 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6959</div>
6960
6961<div class="doc_text">
6962
6963<h5>Syntax:</h5>
6964<pre>
6965 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6966</pre>
6967
6968<h5>Overview:</h5>
6969
6970<p>
6971The '<tt>llvm.var.annotation</tt>' intrinsic
6972</p>
6973
6974<h5>Arguments:</h5>
6975
6976<p>
6977The first argument is a pointer to a value, the second is a pointer to a
6978global string, the third is a pointer to a global string which is the source
6979file name, and the last argument is the line number.
6980</p>
6981
6982<h5>Semantics:</h5>
6983
6984<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6985This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6986This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6987annotations. These have no other defined use, they are ignored by code
6988generation and optimization.
6989</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6990</div>
6991
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6992<!-- _______________________________________________________________________ -->
6993<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6994 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6995</div>
6996
6997<div class="doc_text">
6998
6999<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7000<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7001any integer bit width.
7002</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7003<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7004 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7005 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7006 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7007 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7008 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]7009</pre>
7010
7011<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7012
7013<p>
7014The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7015</p>
7016
7017<h5>Arguments:</h5>
7018
7019<p>
7020The first argument is an integer value (result of some expression),
7021the second is a pointer to a global string, the third is a pointer to a global
7022string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7023It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7024</p>
7025
7026<h5>Semantics:</h5>
7027
7028<p>
7029This intrinsic allows annotations to be put on arbitrary expressions
7030with arbitrary strings. This can be useful for special purpose optimizations
7031that want to look for these annotations. These have no other defined use, they
7032are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]7033</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7034</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7035
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7036<!-- _______________________________________________________________________ -->
7037<div class="doc_subsubsection">
7038 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7039</div>
7040
7041<div class="doc_text">
7042
7043<h5>Syntax:</h5>
7044<pre>
7045 declare void @llvm.trap()
7046</pre>
7047
7048<h5>Overview:</h5>
7049
7050<p>
7051The '<tt>llvm.trap</tt>' intrinsic
7052</p>
7053
7054<h5>Arguments:</h5>
7055
7056<p>
7057None
7058</p>
7059
7060<h5>Semantics:</h5>
7061
7062<p>
7063This intrinsics is lowered to the target dependent trap instruction. If the
7064target does not have a trap instruction, this intrinsic will be lowered to the
7065call of the abort() function.
7066</p>
7067</div>
7068
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7069<!-- _______________________________________________________________________ -->
7070<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7071 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7072</div>
7073<div class="doc_text">
7074<h5>Syntax:</h5>
7075<pre>
7076declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
7077
7078</pre>
7079<h5>Overview:</h5>
7080<p>
7081 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
7082 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
7083 it is placed on the stack before local variables.
7084</p>
7085<h5>Arguments:</h5>
7086<p>
7087 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
7088 first argument is the value loaded from the stack guard
7089 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
7090 has enough space to hold the value of the guard.
7091</p>
7092<h5>Semantics:</h5>
7093<p>
7094 This intrinsic causes the prologue/epilogue inserter to force the position of
7095 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7096 stack. This is to ensure that if a local variable on the stack is overwritten,
7097 it will destroy the value of the guard. When the function exits, the guard on
7098 the stack is checked against the original guard. If they're different, then
7099 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
7100</p>
7101</div>
7102
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7103<!-- *********************************************************************** -->
7104<hr>
7105<address>
7106 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7107 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7108 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7109 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7110
7111 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7112 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7113 Last modified: $Date$
7114</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7115
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7116</body>
7117</html>