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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / f82a52fb5a4bc94c5ad725c74c234da86c5e9063 / . / docs / LangRef.html
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4<head>
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>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]44 </ol>
45 </li>
46 <li><a href="#t_derived">Derived Types</a>
47 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]48 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#t_array">Array Type</a></li>
50 <li><a href="#t_function">Function Type</a></li>
51 <li><a href="#t_pointer">Pointer Type</a></li>
52 <li><a href="#t_struct">Structure Type</a></li>
53 <li><a href="#t_pstruct">Packed Structure Type</a></li>
54 <li><a href="#t_vector">Vector Type</a></li>
55 <li><a href="#t_opaque">Opaque Type</a></li>
56 </ol>
57 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]58 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 </ol>
60 </li>
61 <li><a href="#constants">Constants</a>
62 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]63 <li><a href="#simpleconstants">Simple Constants</a></li>
64 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
65 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
66 <li><a href="#undefvalues">Undefined Values</a></li>
67 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]68 </ol>
69 </li>
70 <li><a href="#othervalues">Other Values</a>
71 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]72 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]73 </ol>
74 </li>
75 <li><a href="#instref">Instruction Reference</a>
76 <ol>
77 <li><a href="#terminators">Terminator Instructions</a>
78 <ol>
79 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
80 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
81 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
82 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
83 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
84 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
85 </ol>
86 </li>
87 <li><a href="#binaryops">Binary Operations</a>
88 <ol>
89 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
90 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
91 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
92 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
93 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
94 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
95 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
96 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
97 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
98 </ol>
99 </li>
100 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
101 <ol>
102 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
103 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
104 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
105 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
106 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
107 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
108 </ol>
109 </li>
110 <li><a href="#vectorops">Vector Operations</a>
111 <ol>
112 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
113 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
114 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
115 </ol>
116 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]117 <li><a href="#aggregateops">Aggregate Operations</a>
118 <ol>
119 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
120 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
121 </ol>
122 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
124 <ol>
125 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
126 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
127 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
128 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
129 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
130 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
131 </ol>
132 </li>
133 <li><a href="#convertops">Conversion Operations</a>
134 <ol>
135 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
141 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
142 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
143 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
144 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
145 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
146 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
147 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]148 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]149 <li><a href="#otherops">Other Operations</a>
150 <ol>
151 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
152 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]153 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
154 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]155 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
156 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
157 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
158 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
159 </ol>
160 </li>
161 </ol>
162 </li>
163 <li><a href="#intrinsics">Intrinsic Functions</a>
164 <ol>
165 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
166 <ol>
167 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
168 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
169 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
170 </ol>
171 </li>
172 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
173 <ol>
174 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
175 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
176 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
177 </ol>
178 </li>
179 <li><a href="#int_codegen">Code Generator Intrinsics</a>
180 <ol>
181 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
182 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
183 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
184 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
185 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
186 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
187 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
188 </ol>
189 </li>
190 <li><a href="#int_libc">Standard C Library Intrinsics</a>
191 <ol>
192 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]197 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]200 </ol>
201 </li>
202 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
203 <ol>
204 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
205 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
210 </ol>
211 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]212 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
213 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]214 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
215 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
218 <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]219 <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]220 </ol>
221 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]222 <li><a href="#int_debugger">Debugger intrinsics</a></li>
223 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]224 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]225 <ol>
226 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]227 </ol>
228 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]229 <li><a href="#int_atomics">Atomic intrinsics</a>
230 <ol>
231 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
232 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
233 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
234 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
235 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
236 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
237 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
238 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
239 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
240 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
241 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
242 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
243 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
244 </ol>
245 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]246 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]247 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]248 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]249 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]250 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]251 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]252 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]253 '<tt>llvm.trap</tt>' Intrinsic</a></li>
254 <li><a href="#int_stackprotector">
255 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]256 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]257 </li>
258 </ol>
259 </li>
260</ol>
261
262<div class="doc_author">
263 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
264 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
265</div>
266
267<!-- *********************************************************************** -->
268<div class="doc_section"> <a name="abstract">Abstract </a></div>
269<!-- *********************************************************************** -->
270
271<div class="doc_text">
272<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]273LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]274type safety, low-level operations, flexibility, and the capability of
275representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]276representation used throughout all phases of the LLVM compilation
277strategy.</p>
278</div>
279
280<!-- *********************************************************************** -->
281<div class="doc_section"> <a name="introduction">Introduction</a> </div>
282<!-- *********************************************************************** -->
283
284<div class="doc_text">
285
286<p>The LLVM code representation is designed to be used in three
287different forms: as an in-memory compiler IR, as an on-disk bitcode
288representation (suitable for fast loading by a Just-In-Time compiler),
289and as a human readable assembly language representation. This allows
290LLVM to provide a powerful intermediate representation for efficient
291compiler transformations and analysis, while providing a natural means
292to debug and visualize the transformations. The three different forms
293of LLVM are all equivalent. This document describes the human readable
294representation and notation.</p>
295
296<p>The LLVM representation aims to be light-weight and low-level
297while being expressive, typed, and extensible at the same time. It
298aims to be a "universal IR" of sorts, by being at a low enough level
299that high-level ideas may be cleanly mapped to it (similar to how
300microprocessors are "universal IR's", allowing many source languages to
301be mapped to them). By providing type information, LLVM can be used as
302the target of optimizations: for example, through pointer analysis, it
303can be proven that a C automatic variable is never accessed outside of
304the current function... allowing it to be promoted to a simple SSA
305value instead of a memory location.</p>
306
307</div>
308
309<!-- _______________________________________________________________________ -->
310<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
311
312<div class="doc_text">
313
314<p>It is important to note that this document describes 'well formed'
315LLVM assembly language. There is a difference between what the parser
316accepts and what is considered 'well formed'. For example, the
317following instruction is syntactically okay, but not well formed:</p>
318
319<div class="doc_code">
320<pre>
321%x = <a href="#i_add">add</a> i32 1, %x
322</pre>
323</div>
324
325<p>...because the definition of <tt>%x</tt> does not dominate all of
326its uses. The LLVM infrastructure provides a verification pass that may
327be used to verify that an LLVM module is well formed. This pass is
328automatically run by the parser after parsing input assembly and by
329the optimizer before it outputs bitcode. The violations pointed out
330by the verifier pass indicate bugs in transformation passes or input to
331the parser.</p>
332</div>
333
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]334<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]335
336<!-- *********************************************************************** -->
337<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
338<!-- *********************************************************************** -->
339
340<div class="doc_text">
341
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]342 <p>LLVM identifiers come in two basic types: global and local. Global
343 identifiers (functions, global variables) begin with the @ character. Local
344 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]345 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]348 <li>Named values are represented as a string of characters with their prefix.
349 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
350 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]351 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]352 with quotes. Special characters may be escaped using "\xx" where xx is the
353 ASCII code for the character in hexadecimal. In this way, any character can
354 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]356 <li>Unnamed values are represented as an unsigned numeric value with their
357 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]358
359 <li>Constants, which are described in a <a href="#constants">section about
360 constants</a>, below.</li>
361</ol>
362
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]363<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]364don't need to worry about name clashes with reserved words, and the set of
365reserved words may be expanded in the future without penalty. Additionally,
366unnamed identifiers allow a compiler to quickly come up with a temporary
367variable without having to avoid symbol table conflicts.</p>
368
369<p>Reserved words in LLVM are very similar to reserved words in other
370languages. There are keywords for different opcodes
371('<tt><a href="#i_add">add</a></tt>',
372 '<tt><a href="#i_bitcast">bitcast</a></tt>',
373 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
374href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
375and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]376none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]377
378<p>Here is an example of LLVM code to multiply the integer variable
379'<tt>%X</tt>' by 8:</p>
380
381<p>The easy way:</p>
382
383<div class="doc_code">
384<pre>
385%result = <a href="#i_mul">mul</a> i32 %X, 8
386</pre>
387</div>
388
389<p>After strength reduction:</p>
390
391<div class="doc_code">
392<pre>
393%result = <a href="#i_shl">shl</a> i32 %X, i8 3
394</pre>
395</div>
396
397<p>And the hard way:</p>
398
399<div class="doc_code">
400<pre>
401<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
402<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
403%result = <a href="#i_add">add</a> i32 %1, %1
404</pre>
405</div>
406
407<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
408important lexical features of LLVM:</p>
409
410<ol>
411
412 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
413 line.</li>
414
415 <li>Unnamed temporaries are created when the result of a computation is not
416 assigned to a named value.</li>
417
418 <li>Unnamed temporaries are numbered sequentially</li>
419
420</ol>
421
422<p>...and it also shows a convention that we follow in this document. When
423demonstrating instructions, we will follow an instruction with a comment that
424defines the type and name of value produced. Comments are shown in italic
425text.</p>
426
427</div>
428
429<!-- *********************************************************************** -->
430<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
431<!-- *********************************************************************** -->
432
433<!-- ======================================================================= -->
434<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
435</div>
436
437<div class="doc_text">
438
439<p>LLVM programs are composed of "Module"s, each of which is a
440translation unit of the input programs. Each module consists of
441functions, global variables, and symbol table entries. Modules may be
442combined together with the LLVM linker, which merges function (and
443global variable) definitions, resolves forward declarations, and merges
444symbol table entries. Here is an example of the "hello world" module:</p>
445
446<div class="doc_code">
447<pre><i>; Declare the string constant as a global constant...</i>
448<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
449 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
450
451<i>; External declaration of the puts function</i>
452<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
453
454<i>; Definition of main function</i>
455define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]456 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]457 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]458 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]459
460 <i>; Call puts function to write out the string to stdout...</i>
461 <a
462 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
463 <a
464 href="#i_ret">ret</a> i32 0<br>}<br>
465</pre>
466</div>
467
468<p>This example is made up of a <a href="#globalvars">global variable</a>
469named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
470function, and a <a href="#functionstructure">function definition</a>
471for "<tt>main</tt>".</p>
472
473<p>In general, a module is made up of a list of global values,
474where both functions and global variables are global values. Global values are
475represented by a pointer to a memory location (in this case, a pointer to an
476array of char, and a pointer to a function), and have one of the following <a
477href="#linkage">linkage types</a>.</p>
478
479</div>
480
481<!-- ======================================================================= -->
482<div class="doc_subsection">
483 <a name="linkage">Linkage Types</a>
484</div>
485
486<div class="doc_text">
487
488<p>
489All Global Variables and Functions have one of the following types of linkage:
490</p>
491
492<dl>
493
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]494 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
495
496 <dd>Global values with private linkage are only directly accessible by
497 objects in the current module. In particular, linking code into a module with
498 an private global value may cause the private to be renamed as necessary to
499 avoid collisions. Because the symbol is private to the module, all
500 references can be updated. This doesn't show up in any symbol table in the
501 object file.
502 </dd>
503
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]504 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]505
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]506 <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]507 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]508 '<tt>static</tt>' keyword in C.
509 </dd>
510
511 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
512
513 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
514 the same name when linkage occurs. This is typically used to implement
515 inline functions, templates, or other code which must be generated in each
516 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
517 allowed to be discarded.
518 </dd>
519
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]520 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
521
522 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
523 linkage, except that unreferenced <tt>common</tt> globals may not be
524 discarded. This is used for globals that may be emitted in multiple
525 translation units, but that are not guaranteed to be emitted into every
526 translation unit that uses them. One example of this is tentative
527 definitions in C, such as "<tt>int X;</tt>" at global scope.
528 </dd>
529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
531
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]532 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
533 that some targets may choose to emit different assembly sequences for them
534 for target-dependent reasons. This is used for globals that are declared
535 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]536 </dd>
537
538 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
539
540 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
541 pointer to array type. When two global variables with appending linkage are
542 linked together, the two global arrays are appended together. This is the
543 LLVM, typesafe, equivalent of having the system linker append together
544 "sections" with identical names when .o files are linked.
545 </dd>
546
547 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]548 <dd>The semantics of this linkage follow the ELF object file model: the
549 symbol is weak until linked, if not linked, the symbol becomes null instead
550 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]551 </dd>
552
553 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
554
555 <dd>If none of the above identifiers are used, the global is externally
556 visible, meaning that it participates in linkage and can be used to resolve
557 external symbol references.
558 </dd>
559</dl>
560
561 <p>
562 The next two types of linkage are targeted for Microsoft Windows platform
563 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]564 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]565 </p>
566
567 <dl>
568 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
569
570 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
571 or variable via a global pointer to a pointer that is set up by the DLL
572 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]573 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]574 </dd>
575
576 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
577
578 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
579 pointer to a pointer in a DLL, so that it can be referenced with the
580 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]581 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]582 name.
583 </dd>
584
585</dl>
586
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]587<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
589variable and was linked with this one, one of the two would be renamed,
590preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
591external (i.e., lacking any linkage declarations), they are accessible
592outside of the current module.</p>
593<p>It is illegal for a function <i>declaration</i>
594to have any linkage type other than "externally visible", <tt>dllimport</tt>,
595or <tt>extern_weak</tt>.</p>
596<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]597linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]598</div>
599
600<!-- ======================================================================= -->
601<div class="doc_subsection">
602 <a name="callingconv">Calling Conventions</a>
603</div>
604
605<div class="doc_text">
606
607<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
608and <a href="#i_invoke">invokes</a> can all have an optional calling convention
609specified for the call. The calling convention of any pair of dynamic
610caller/callee must match, or the behavior of the program is undefined. The
611following calling conventions are supported by LLVM, and more may be added in
612the future:</p>
613
614<dl>
615 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
616
617 <dd>This calling convention (the default if no other calling convention is
618 specified) matches the target C calling conventions. This calling convention
619 supports varargs function calls and tolerates some mismatch in the declared
620 prototype and implemented declaration of the function (as does normal C).
621 </dd>
622
623 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
624
625 <dd>This calling convention attempts to make calls as fast as possible
626 (e.g. by passing things in registers). This calling convention allows the
627 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]628 without having to conform to an externally specified ABI (Application Binary
629 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]630 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
631 supported. This calling convention does not support varargs and requires the
632 prototype of all callees to exactly match the prototype of the function
633 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]634 </dd>
635
636 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
637
638 <dd>This calling convention attempts to make code in the caller as efficient
639 as possible under the assumption that the call is not commonly executed. As
640 such, these calls often preserve all registers so that the call does not break
641 any live ranges in the caller side. This calling convention does not support
642 varargs and requires the prototype of all callees to exactly match the
643 prototype of the function definition.
644 </dd>
645
646 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
647
648 <dd>Any calling convention may be specified by number, allowing
649 target-specific calling conventions to be used. Target specific calling
650 conventions start at 64.
651 </dd>
652</dl>
653
654<p>More calling conventions can be added/defined on an as-needed basis, to
655support pascal conventions or any other well-known target-independent
656convention.</p>
657
658</div>
659
660<!-- ======================================================================= -->
661<div class="doc_subsection">
662 <a name="visibility">Visibility Styles</a>
663</div>
664
665<div class="doc_text">
666
667<p>
668All Global Variables and Functions have one of the following visibility styles:
669</p>
670
671<dl>
672 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
673
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]674 <dd>On targets that use the ELF object file format, default visibility means
675 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]676 modules and, in shared libraries, means that the declared entity may be
677 overridden. On Darwin, default visibility means that the declaration is
678 visible to other modules. Default visibility corresponds to "external
679 linkage" in the language.
680 </dd>
681
682 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
683
684 <dd>Two declarations of an object with hidden visibility refer to the same
685 object if they are in the same shared object. Usually, hidden visibility
686 indicates that the symbol will not be placed into the dynamic symbol table,
687 so no other module (executable or shared library) can reference it
688 directly.
689 </dd>
690
691 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
692
693 <dd>On ELF, protected visibility indicates that the symbol will be placed in
694 the dynamic symbol table, but that references within the defining module will
695 bind to the local symbol. That is, the symbol cannot be overridden by another
696 module.
697 </dd>
698</dl>
699
700</div>
701
702<!-- ======================================================================= -->
703<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]704 <a name="namedtypes">Named Types</a>
705</div>
706
707<div class="doc_text">
708
709<p>LLVM IR allows you to specify name aliases for certain types. This can make
710it easier to read the IR and make the IR more condensed (particularly when
711recursive types are involved). An example of a name specification is:
712</p>
713
714<div class="doc_code">
715<pre>
716%mytype = type { %mytype*, i32 }
717</pre>
718</div>
719
720<p>You may give a name to any <a href="#typesystem">type</a> except "<a
721href="t_void">void</a>". Type name aliases may be used anywhere a type is
722expected with the syntax "%mytype".</p>
723
724<p>Note that type names are aliases for the structural type that they indicate,
725and that you can therefore specify multiple names for the same type. This often
726leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
727structural typing, the name is not part of the type. When printing out LLVM IR,
728the printer will pick <em>one name</em> to render all types of a particular
729shape. This means that if you have code where two different source types end up
730having the same LLVM type, that the dumper will sometimes print the "wrong" or
731unexpected type. This is an important design point and isn't going to
732change.</p>
733
734</div>
735
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]736<!-- ======================================================================= -->
737<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]738 <a name="globalvars">Global Variables</a>
739</div>
740
741<div class="doc_text">
742
743<p>Global variables define regions of memory allocated at compilation time
744instead of run-time. Global variables may optionally be initialized, may have
745an explicit section to be placed in, and may have an optional explicit alignment
746specified. A variable may be defined as "thread_local", which means that it
747will not be shared by threads (each thread will have a separated copy of the
748variable). A variable may be defined as a global "constant," which indicates
749that the contents of the variable will <b>never</b> be modified (enabling better
750optimization, allowing the global data to be placed in the read-only section of
751an executable, etc). Note that variables that need runtime initialization
752cannot be marked "constant" as there is a store to the variable.</p>
753
754<p>
755LLVM explicitly allows <em>declarations</em> of global variables to be marked
756constant, even if the final definition of the global is not. This capability
757can be used to enable slightly better optimization of the program, but requires
758the language definition to guarantee that optimizations based on the
759'constantness' are valid for the translation units that do not include the
760definition.
761</p>
762
763<p>As SSA values, global variables define pointer values that are in
764scope (i.e. they dominate) all basic blocks in the program. Global
765variables always define a pointer to their "content" type because they
766describe a region of memory, and all memory objects in LLVM are
767accessed through pointers.</p>
768
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]769<p>A global variable may be declared to reside in a target-specifc numbered
770address space. For targets that support them, address spaces may affect how
771optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]772the variable. The default address space is zero. The address space qualifier
773must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]775<p>LLVM allows an explicit section to be specified for globals. If the target
776supports it, it will emit globals to the section specified.</p>
777
778<p>An explicit alignment may be specified for a global. If not present, or if
779the alignment is set to zero, the alignment of the global is set by the target
780to whatever it feels convenient. If an explicit alignment is specified, the
781global is forced to have at least that much alignment. All alignments must be
782a power of 2.</p>
783
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]784<p>For example, the following defines a global in a numbered address space with
785an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]786
787<div class="doc_code">
788<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]789@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]790</pre>
791</div>
792
793</div>
794
795
796<!-- ======================================================================= -->
797<div class="doc_subsection">
798 <a name="functionstructure">Functions</a>
799</div>
800
801<div class="doc_text">
802
803<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
804an optional <a href="#linkage">linkage type</a>, an optional
805<a href="#visibility">visibility style</a>, an optional
806<a href="#callingconv">calling convention</a>, a return type, an optional
807<a href="#paramattrs">parameter attribute</a> for the return type, a function
808name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]809<a href="#paramattrs">parameter attributes</a>), optional
810<a href="#fnattrs">function attributes</a>, an optional section,
811an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]812an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813
814LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
815optional <a href="#linkage">linkage type</a>, an optional
816<a href="#visibility">visibility style</a>, an optional
817<a href="#callingconv">calling convention</a>, a return type, an optional
818<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]819name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]820<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]821
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]822<p>A function definition contains a list of basic blocks, forming the CFG
823(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]824the function. Each basic block may optionally start with a label (giving the
825basic block a symbol table entry), contains a list of instructions, and ends
826with a <a href="#terminators">terminator</a> instruction (such as a branch or
827function return).</p>
828
829<p>The first basic block in a function is special in two ways: it is immediately
830executed on entrance to the function, and it is not allowed to have predecessor
831basic blocks (i.e. there can not be any branches to the entry block of a
832function). Because the block can have no predecessors, it also cannot have any
833<a href="#i_phi">PHI nodes</a>.</p>
834
835<p>LLVM allows an explicit section to be specified for functions. If the target
836supports it, it will emit functions to the section specified.</p>
837
838<p>An explicit alignment may be specified for a function. If not present, or if
839the alignment is set to zero, the alignment of the function is set by the target
840to whatever it feels convenient. If an explicit alignment is specified, the
841function is forced to have at least that much alignment. All alignments must be
842a power of 2.</p>
843
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]844 <h5>Syntax:</h5>
845
846<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]847<tt>
848define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
849 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
850 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
851 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
852 [<a href="#gc">gc</a>] { ... }
853</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]854</div>
855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856</div>
857
858
859<!-- ======================================================================= -->
860<div class="doc_subsection">
861 <a name="aliasstructure">Aliases</a>
862</div>
863<div class="doc_text">
864 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]865 function, global variable, another alias or bitcast of global value). Aliases
866 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]867 optional <a href="#visibility">visibility style</a>.</p>
868
869 <h5>Syntax:</h5>
870
871<div class="doc_code">
872<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]873@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]874</pre>
875</div>
876
877</div>
878
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
883<div class="doc_text">
884 <p>The return type and each parameter of a function type may have a set of
885 <i>parameter attributes</i> associated with them. Parameter attributes are
886 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]887 a function. Parameter attributes are considered to be part of the function,
888 not of the function type, so functions with different parameter attributes
889 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890
891 <p>Parameter attributes are simple keywords that follow the type specified. If
892 multiple parameter attributes are needed, they are space separated. For
893 example:</p>
894
895<div class="doc_code">
896<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]897declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]898declare i32 @atoi(i8 zeroext)
899declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]900</pre>
901</div>
902
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]903 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
904 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]905
906 <p>Currently, only the following parameter attributes are defined:</p>
907 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]908 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]909 <dd>This indicates to the code generator that the parameter or return value
910 should be zero-extended to a 32-bit value by the caller (for a parameter)
911 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]912
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]913 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]914 <dd>This indicates to the code generator that the parameter or return value
915 should be sign-extended to a 32-bit value by the caller (for a parameter)
916 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]917
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]918 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]919 <dd>This indicates that this parameter or return value should be treated
920 in a special target-dependent fashion during while emitting code for a
921 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]922 to memory, though some targets use it to distinguish between two different
923 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]924
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]925 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]926 <dd>This indicates that the pointer parameter should really be passed by
927 value to the function. The attribute implies that a hidden copy of the
928 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]929 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]930 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]931 value, but is also valid on pointers to scalars. The copy is considered to
932 belong to the caller not the callee (for example,
933 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]934 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]935 values. The byval attribute also supports specifying an alignment with the
936 align attribute. This has a target-specific effect on the code generator
937 that usually indicates a desired alignment for the synthesized stack
938 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]940 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]941 <dd>This indicates that the pointer parameter specifies the address of a
942 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]943 This pointer must be guaranteed by the caller to be valid: loads and stores
944 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]945 be applied to the first parameter. This is not a valid attribute for
946 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]947
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]948 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]949 <dd>This indicates that the pointer does not alias any global or any other
950 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]951 case. On a function return value, <tt>noalias</tt> additionally indicates
952 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]953 caller. For further details, please see the discussion of the NoAlias
954 response in
955 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
956 analysis</a>.</dd>
957
958 <dt><tt>nocapture</tt></dt>
959 <dd>This indicates that the callee does not make any copies of the pointer
960 that outlive the callee itself. This is not a valid attribute for return
961 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]962
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]963 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]964 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]965 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
966 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]967 </dl>
968
969</div>
970
971<!-- ======================================================================= -->
972<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]973 <a name="gc">Garbage Collector Names</a>
974</div>
975
976<div class="doc_text">
977<p>Each function may specify a garbage collector name, which is simply a
978string.</p>
979
980<div class="doc_code"><pre
981>define void @f() gc "name" { ...</pre></div>
982
983<p>The compiler declares the supported values of <i>name</i>. Specifying a
984collector which will cause the compiler to alter its output in order to support
985the named garbage collection algorithm.</p>
986</div>
987
988<!-- ======================================================================= -->
989<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]990 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]991</div>
992
993<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]994
995<p>Function attributes are set to communicate additional information about
996 a function. Function attributes are considered to be part of the function,
997 not of the function type, so functions with different parameter attributes
998 can have the same function type.</p>
999
1000 <p>Function attributes are simple keywords that follow the type specified. If
1001 multiple attributes are needed, they are space separated. For
1002 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1003
1004<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1005<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1006define void @f() noinline { ... }
1007define void @f() alwaysinline { ... }
1008define void @f() alwaysinline optsize { ... }
1009define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1010</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1011</div>
1012
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1013<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1014<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1015<dd>This attribute indicates that the inliner should attempt to inline this
1016function into callers whenever possible, ignoring any active inlining size
1017threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1018
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1019<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1020<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1021in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1022<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1023
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1024<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1025<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1026make choices that keep the code size of this function low, and otherwise do
1027optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1028
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1029<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1030<dd>This function attribute indicates that the function never returns normally.
1031This produces undefined behavior at runtime if the function ever does
1032dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1033
1034<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1035<dd>This function attribute indicates that the function never returns with an
1036unwind or exceptional control flow. If the function does unwind, its runtime
1037behavior is undefined.</dd>
1038
1039<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1040<dd>This attribute indicates that the function computes its result (or the
1041exception it throws) based strictly on its arguments, without dereferencing any
1042pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1043registers, etc) visible to caller functions. It does not write through any
1044pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
1045never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1046
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1047<dt><tt><a name="readonly">readonly</a></tt></dt>
1048<dd>This attribute indicates that the function does not write through any
1049pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1050or otherwise modify any state (e.g. memory, control registers, etc) visible to
1051caller functions. It may dereference pointer arguments and read state that may
1052be set in the caller. A readonly function always returns the same value (or
1053throws the same exception) when called with the same set of arguments and global
1054state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1055
1056<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1057<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1058protector. It is in the form of a "canary"&mdash;a random value placed on the
1059stack before the local variables that's checked upon return from the function to
1060see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1061needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1062
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1063<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1064that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1065have an <tt>ssp</tt> attribute.</p></dd>
1066
1067<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1068<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1069stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1070function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1071
1072<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1073function that doesn't have an <tt>sspreq</tt> attribute or which has
1074an <tt>ssp</tt> attribute, then the resulting function will have
1075an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1076</dl>
1077
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1078</div>
1079
1080<!-- ======================================================================= -->
1081<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1082 <a name="moduleasm">Module-Level Inline Assembly</a>
1083</div>
1084
1085<div class="doc_text">
1086<p>
1087Modules may contain "module-level inline asm" blocks, which corresponds to the
1088GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1089LLVM and treated as a single unit, but may be separated in the .ll file if
1090desired. The syntax is very simple:
1091</p>
1092
1093<div class="doc_code">
1094<pre>
1095module asm "inline asm code goes here"
1096module asm "more can go here"
1097</pre>
1098</div>
1099
1100<p>The strings can contain any character by escaping non-printable characters.
1101 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1102 for the number.
1103</p>
1104
1105<p>
1106 The inline asm code is simply printed to the machine code .s file when
1107 assembly code is generated.
1108</p>
1109</div>
1110
1111<!-- ======================================================================= -->
1112<div class="doc_subsection">
1113 <a name="datalayout">Data Layout</a>
1114</div>
1115
1116<div class="doc_text">
1117<p>A module may specify a target specific data layout string that specifies how
1118data is to be laid out in memory. The syntax for the data layout is simply:</p>
1119<pre> target datalayout = "<i>layout specification</i>"</pre>
1120<p>The <i>layout specification</i> consists of a list of specifications
1121separated by the minus sign character ('-'). Each specification starts with a
1122letter and may include other information after the letter to define some
1123aspect of the data layout. The specifications accepted are as follows: </p>
1124<dl>
1125 <dt><tt>E</tt></dt>
1126 <dd>Specifies that the target lays out data in big-endian form. That is, the
1127 bits with the most significance have the lowest address location.</dd>
1128 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1129 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1130 the bits with the least significance have the lowest address location.</dd>
1131 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1132 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1133 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1134 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1135 too.</dd>
1136 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1137 <dd>This specifies the alignment for an integer type of a given bit
1138 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1139 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1140 <dd>This specifies the alignment for a vector type of a given bit
1141 <i>size</i>.</dd>
1142 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1143 <dd>This specifies the alignment for a floating point type of a given bit
1144 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1145 (double).</dd>
1146 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1147 <dd>This specifies the alignment for an aggregate type of a given bit
1148 <i>size</i>.</dd>
1149</dl>
1150<p>When constructing the data layout for a given target, LLVM starts with a
1151default set of specifications which are then (possibly) overriden by the
1152specifications in the <tt>datalayout</tt> keyword. The default specifications
1153are given in this list:</p>
1154<ul>
1155 <li><tt>E</tt> - big endian</li>
1156 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1157 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1158 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1159 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1160 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1161 <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]1162 alignment of 64-bits</li>
1163 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1164 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1165 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1166 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1167 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1168</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1169<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1170following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1171<ol>
1172 <li>If the type sought is an exact match for one of the specifications, that
1173 specification is used.</li>
1174 <li>If no match is found, and the type sought is an integer type, then the
1175 smallest integer type that is larger than the bitwidth of the sought type is
1176 used. If none of the specifications are larger than the bitwidth then the the
1177 largest integer type is used. For example, given the default specifications
1178 above, the i7 type will use the alignment of i8 (next largest) while both
1179 i65 and i256 will use the alignment of i64 (largest specified).</li>
1180 <li>If no match is found, and the type sought is a vector type, then the
1181 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1182 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1183 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1184</ol>
1185</div>
1186
1187<!-- *********************************************************************** -->
1188<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1189<!-- *********************************************************************** -->
1190
1191<div class="doc_text">
1192
1193<p>The LLVM type system is one of the most important features of the
1194intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1195optimizations to be performed on the intermediate representation directly,
1196without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1197extra analyses on the side before the transformation. A strong type
1198system makes it easier to read the generated code and enables novel
1199analyses and transformations that are not feasible to perform on normal
1200three address code representations.</p>
1201
1202</div>
1203
1204<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1205<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1206Classifications</a> </div>
1207<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1208<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1209classifications:</p>
1210
1211<table border="1" cellspacing="0" cellpadding="4">
1212 <tbody>
1213 <tr><th>Classification</th><th>Types</th></tr>
1214 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1215 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1216 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1217 </tr>
1218 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1219 <td><a href="#t_floating">floating point</a></td>
1220 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1221 </tr>
1222 <tr>
1223 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1224 <td><a href="#t_integer">integer</a>,
1225 <a href="#t_floating">floating point</a>,
1226 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1227 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1228 <a href="#t_struct">structure</a>,
1229 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1230 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1231 </td>
1232 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1233 <tr>
1234 <td><a href="#t_primitive">primitive</a></td>
1235 <td><a href="#t_label">label</a>,
1236 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1237 <a href="#t_floating">floating point</a>.</td>
1238 </tr>
1239 <tr>
1240 <td><a href="#t_derived">derived</a></td>
1241 <td><a href="#t_integer">integer</a>,
1242 <a href="#t_array">array</a>,
1243 <a href="#t_function">function</a>,
1244 <a href="#t_pointer">pointer</a>,
1245 <a href="#t_struct">structure</a>,
1246 <a href="#t_pstruct">packed structure</a>,
1247 <a href="#t_vector">vector</a>,
1248 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1249 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1250 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1251 </tbody>
1252</table>
1253
1254<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1255most important. Values of these types are the only ones which can be
1256produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1257instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1258</div>
1259
1260<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1261<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1262
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1263<div class="doc_text">
1264<p>The primitive types are the fundamental building blocks of the LLVM
1265system.</p>
1266
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1267</div>
1268
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1269<!-- _______________________________________________________________________ -->
1270<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1271
1272<div class="doc_text">
1273 <table>
1274 <tbody>
1275 <tr><th>Type</th><th>Description</th></tr>
1276 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1277 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1278 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1279 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1280 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1281 </tbody>
1282 </table>
1283</div>
1284
1285<!-- _______________________________________________________________________ -->
1286<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1287
1288<div class="doc_text">
1289<h5>Overview:</h5>
1290<p>The void type does not represent any value and has no size.</p>
1291
1292<h5>Syntax:</h5>
1293
1294<pre>
1295 void
1296</pre>
1297</div>
1298
1299<!-- _______________________________________________________________________ -->
1300<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1301
1302<div class="doc_text">
1303<h5>Overview:</h5>
1304<p>The label type represents code labels.</p>
1305
1306<h5>Syntax:</h5>
1307
1308<pre>
1309 label
1310</pre>
1311</div>
1312
1313
1314<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1315<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1316
1317<div class="doc_text">
1318
1319<p>The real power in LLVM comes from the derived types in the system.
1320This is what allows a programmer to represent arrays, functions,
1321pointers, and other useful types. Note that these derived types may be
1322recursive: For example, it is possible to have a two dimensional array.</p>
1323
1324</div>
1325
1326<!-- _______________________________________________________________________ -->
1327<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1328
1329<div class="doc_text">
1330
1331<h5>Overview:</h5>
1332<p>The integer type is a very simple derived type that simply specifies an
1333arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13342^23-1 (about 8 million) can be specified.</p>
1335
1336<h5>Syntax:</h5>
1337
1338<pre>
1339 iN
1340</pre>
1341
1342<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1343value.</p>
1344
1345<h5>Examples:</h5>
1346<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1347 <tbody>
1348 <tr>
1349 <td><tt>i1</tt></td>
1350 <td>a single-bit integer.</td>
1351 </tr><tr>
1352 <td><tt>i32</tt></td>
1353 <td>a 32-bit integer.</td>
1354 </tr><tr>
1355 <td><tt>i1942652</tt></td>
1356 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1357 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1358 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1359</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1360
1361<p>Note that the code generator does not yet support large integer types
1362to be used as function return types. The specific limit on how large a
1363return type the code generator can currently handle is target-dependent;
1364currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1365targets.</p>
1366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1367</div>
1368
1369<!-- _______________________________________________________________________ -->
1370<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1371
1372<div class="doc_text">
1373
1374<h5>Overview:</h5>
1375
1376<p>The array type is a very simple derived type that arranges elements
1377sequentially in memory. The array type requires a size (number of
1378elements) and an underlying data type.</p>
1379
1380<h5>Syntax:</h5>
1381
1382<pre>
1383 [&lt;# elements&gt; x &lt;elementtype&gt;]
1384</pre>
1385
1386<p>The number of elements is a constant integer value; elementtype may
1387be any type with a size.</p>
1388
1389<h5>Examples:</h5>
1390<table class="layout">
1391 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1392 <td class="left"><tt>[40 x i32]</tt></td>
1393 <td class="left">Array of 40 32-bit integer values.</td>
1394 </tr>
1395 <tr class="layout">
1396 <td class="left"><tt>[41 x i32]</tt></td>
1397 <td class="left">Array of 41 32-bit integer values.</td>
1398 </tr>
1399 <tr class="layout">
1400 <td class="left"><tt>[4 x i8]</tt></td>
1401 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1402 </tr>
1403</table>
1404<p>Here are some examples of multidimensional arrays:</p>
1405<table class="layout">
1406 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1407 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1408 <td class="left">3x4 array of 32-bit integer values.</td>
1409 </tr>
1410 <tr class="layout">
1411 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1412 <td class="left">12x10 array of single precision floating point values.</td>
1413 </tr>
1414 <tr class="layout">
1415 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1416 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1417 </tr>
1418</table>
1419
1420<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1421length array. Normally, accesses past the end of an array are undefined in
1422LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1423As a special case, however, zero length arrays are recognized to be variable
1424length. This allows implementation of 'pascal style arrays' with the LLVM
1425type "{ i32, [0 x float]}", for example.</p>
1426
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1427<p>Note that the code generator does not yet support large aggregate types
1428to be used as function return types. The specific limit on how large an
1429aggregate return type the code generator can currently handle is
1430target-dependent, and also dependent on the aggregate element types.</p>
1431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1432</div>
1433
1434<!-- _______________________________________________________________________ -->
1435<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1436<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1437
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1438<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1440<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1441consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1442return 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]1443If 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]1444class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1445
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1446<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1447
1448<pre>
1449 &lt;returntype list&gt; (&lt;parameter list&gt;)
1450</pre>
1451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1452<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1453specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1454which indicates that the function takes a variable number of arguments.
1455Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1456 href="#int_varargs">variable argument handling intrinsic</a> functions.
1457'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1458<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1459
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1460<h5>Examples:</h5>
1461<table class="layout">
1462 <tr class="layout">
1463 <td class="left"><tt>i32 (i32)</tt></td>
1464 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1465 </td>
1466 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1467 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1468 </tt></td>
1469 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1470 an <tt>i16</tt> that should be sign extended and a
1471 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1472 <tt>float</tt>.
1473 </td>
1474 </tr><tr class="layout">
1475 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1476 <td class="left">A vararg function that takes at least one
1477 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1478 which returns an integer. This is the signature for <tt>printf</tt> in
1479 LLVM.
1480 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1481 </tr><tr class="layout">
1482 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1483 <td class="left">A function taking an <tt>i32</tt>, returning two
1484 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1485 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1486 </tr>
1487</table>
1488
1489</div>
1490<!-- _______________________________________________________________________ -->
1491<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1492<div class="doc_text">
1493<h5>Overview:</h5>
1494<p>The structure type is used to represent a collection of data members
1495together in memory. The packing of the field types is defined to match
1496the ABI of the underlying processor. The elements of a structure may
1497be any type that has a size.</p>
1498<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1499and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1500field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1501instruction.</p>
1502<h5>Syntax:</h5>
1503<pre> { &lt;type list&gt; }<br></pre>
1504<h5>Examples:</h5>
1505<table class="layout">
1506 <tr class="layout">
1507 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1508 <td class="left">A triple of three <tt>i32</tt> values</td>
1509 </tr><tr class="layout">
1510 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1511 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1512 second element is a <a href="#t_pointer">pointer</a> to a
1513 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1514 an <tt>i32</tt>.</td>
1515 </tr>
1516</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1517
1518<p>Note that the code generator does not yet support large aggregate types
1519to be used as function return types. The specific limit on how large an
1520aggregate return type the code generator can currently handle is
1521target-dependent, and also dependent on the aggregate element types.</p>
1522
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1523</div>
1524
1525<!-- _______________________________________________________________________ -->
1526<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1527</div>
1528<div class="doc_text">
1529<h5>Overview:</h5>
1530<p>The packed structure type is used to represent a collection of data members
1531together in memory. There is no padding between fields. Further, the alignment
1532of a packed structure is 1 byte. The elements of a packed structure may
1533be any type that has a size.</p>
1534<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1535and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1536field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1537instruction.</p>
1538<h5>Syntax:</h5>
1539<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1540<h5>Examples:</h5>
1541<table class="layout">
1542 <tr class="layout">
1543 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1544 <td class="left">A triple of three <tt>i32</tt> values</td>
1545 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1546 <td class="left">
1547<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1548 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1549 second element is a <a href="#t_pointer">pointer</a> to a
1550 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1551 an <tt>i32</tt>.</td>
1552 </tr>
1553</table>
1554</div>
1555
1556<!-- _______________________________________________________________________ -->
1557<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1558<div class="doc_text">
1559<h5>Overview:</h5>
1560<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1561reference to another object, which must live in memory. Pointer types may have
1562an optional address space attribute defining the target-specific numbered
1563address space where the pointed-to object resides. The default address space is
1564zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1565
1566<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]1567it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1568
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1569<h5>Syntax:</h5>
1570<pre> &lt;type&gt; *<br></pre>
1571<h5>Examples:</h5>
1572<table class="layout">
1573 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1574 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1575 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1576 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1577 </tr>
1578 <tr class="layout">
1579 <td class="left"><tt>i32 (i32 *) *</tt></td>
1580 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1581 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1582 <tt>i32</tt>.</td>
1583 </tr>
1584 <tr class="layout">
1585 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1586 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1587 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1588 </tr>
1589</table>
1590</div>
1591
1592<!-- _______________________________________________________________________ -->
1593<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1594<div class="doc_text">
1595
1596<h5>Overview:</h5>
1597
1598<p>A vector type is a simple derived type that represents a vector
1599of elements. Vector types are used when multiple primitive data
1600are operated in parallel using a single instruction (SIMD).
1601A vector type requires a size (number of
1602elements) and an underlying primitive data type. Vectors must have a power
1603of two length (1, 2, 4, 8, 16 ...). Vector types are
1604considered <a href="#t_firstclass">first class</a>.</p>
1605
1606<h5>Syntax:</h5>
1607
1608<pre>
1609 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1610</pre>
1611
1612<p>The number of elements is a constant integer value; elementtype may
1613be any integer or floating point type.</p>
1614
1615<h5>Examples:</h5>
1616
1617<table class="layout">
1618 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1619 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1620 <td class="left">Vector of 4 32-bit integer values.</td>
1621 </tr>
1622 <tr class="layout">
1623 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1624 <td class="left">Vector of 8 32-bit floating-point values.</td>
1625 </tr>
1626 <tr class="layout">
1627 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1628 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1629 </tr>
1630</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1631
1632<p>Note that the code generator does not yet support large vector types
1633to be used as function return types. The specific limit on how large a
1634vector return type codegen can currently handle is target-dependent;
1635currently it's often a few times longer than a hardware vector register.</p>
1636
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1637</div>
1638
1639<!-- _______________________________________________________________________ -->
1640<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1641<div class="doc_text">
1642
1643<h5>Overview:</h5>
1644
1645<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1646corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1647In LLVM, opaque types can eventually be resolved to any type (not just a
1648structure type).</p>
1649
1650<h5>Syntax:</h5>
1651
1652<pre>
1653 opaque
1654</pre>
1655
1656<h5>Examples:</h5>
1657
1658<table class="layout">
1659 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1660 <td class="left"><tt>opaque</tt></td>
1661 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1662 </tr>
1663</table>
1664</div>
1665
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1666<!-- ======================================================================= -->
1667<div class="doc_subsection">
1668 <a name="t_uprefs">Type Up-references</a>
1669</div>
1670
1671<div class="doc_text">
1672<h5>Overview:</h5>
1673<p>
1674An "up reference" allows you to refer to a lexically enclosing type without
1675requiring it to have a name. For instance, a structure declaration may contain a
1676pointer to any of the types it is lexically a member of. Example of up
1677references (with their equivalent as named type declarations) include:</p>
1678
1679<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1680 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1681 { \2 }* %y = type { %y }*
1682 \1* %z = type %z*
1683</pre>
1684
1685<p>
1686An up reference is needed by the asmprinter for printing out cyclic types when
1687there is no declared name for a type in the cycle. Because the asmprinter does
1688not want to print out an infinite type string, it needs a syntax to handle
1689recursive types that have no names (all names are optional in llvm IR).
1690</p>
1691
1692<h5>Syntax:</h5>
1693<pre>
1694 \&lt;level&gt;
1695</pre>
1696
1697<p>
1698The level is the count of the lexical type that is being referred to.
1699</p>
1700
1701<h5>Examples:</h5>
1702
1703<table class="layout">
1704 <tr class="layout">
1705 <td class="left"><tt>\1*</tt></td>
1706 <td class="left">Self-referential pointer.</td>
1707 </tr>
1708 <tr class="layout">
1709 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1710 <td class="left">Recursive structure where the upref refers to the out-most
1711 structure.</td>
1712 </tr>
1713</table>
1714</div>
1715
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1716
1717<!-- *********************************************************************** -->
1718<div class="doc_section"> <a name="constants">Constants</a> </div>
1719<!-- *********************************************************************** -->
1720
1721<div class="doc_text">
1722
1723<p>LLVM has several different basic types of constants. This section describes
1724them all and their syntax.</p>
1725
1726</div>
1727
1728<!-- ======================================================================= -->
1729<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1730
1731<div class="doc_text">
1732
1733<dl>
1734 <dt><b>Boolean constants</b></dt>
1735
1736 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1737 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1738 </dd>
1739
1740 <dt><b>Integer constants</b></dt>
1741
1742 <dd>Standard integers (such as '4') are constants of the <a
1743 href="#t_integer">integer</a> type. Negative numbers may be used with
1744 integer types.
1745 </dd>
1746
1747 <dt><b>Floating point constants</b></dt>
1748
1749 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1750 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1751 notation (see below). The assembler requires the exact decimal value of
1752 a floating-point constant. For example, the assembler accepts 1.25 but
1753 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1754 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1755
1756 <dt><b>Null pointer constants</b></dt>
1757
1758 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1759 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1760
1761</dl>
1762
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame^]1763<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1764of floating point constants. For example, the form '<tt>double
17650x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
17664.5e+15</tt>'. The only time hexadecimal floating point constants are required
1767(and the only time that they are generated by the disassembler) is when a
1768floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame^]1769decimal floating point number in a reasonable number of digits. For example,
1770NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1771special values are represented in their IEEE hexadecimal format so that
1772assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame^]1773<p>When using the hexadecimal form, constants of types float and double are
1774represented using the 16-digit form shown above (which matches the IEEE754
1775representation for double); float values must, however, be exactly representable
1776as IEE754 single precision.
1777Hexadecimal format is always used for long
1778double, and there are three forms of long double. The 80-bit
1779format used by x86 is represented as <tt>0xK</tt>
1780followed by 20 hexadecimal digits.
1781The 128-bit format used by PowerPC (two adjacent doubles) is represented
1782by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1783format is represented
1784by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1785target uses this format. Long doubles will only work if they match
1786the long double format on your target. All hexadecimal formats are big-endian
1787(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1788</div>
1789
1790<!-- ======================================================================= -->
1791<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1792</div>
1793
1794<div class="doc_text">
1795<p>Aggregate constants arise from aggregation of simple constants
1796and smaller aggregate constants.</p>
1797
1798<dl>
1799 <dt><b>Structure constants</b></dt>
1800
1801 <dd>Structure constants are represented with notation similar to structure
1802 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1803 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1804 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]1805 must have <a href="#t_struct">structure type</a>, and the number and
1806 types of elements must match those specified by the type.
1807 </dd>
1808
1809 <dt><b>Array constants</b></dt>
1810
1811 <dd>Array constants are represented with notation similar to array type
1812 definitions (a comma separated list of elements, surrounded by square brackets
1813 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1814 constants must have <a href="#t_array">array type</a>, and the number and
1815 types of elements must match those specified by the type.
1816 </dd>
1817
1818 <dt><b>Vector constants</b></dt>
1819
1820 <dd>Vector constants are represented with notation similar to vector type
1821 definitions (a comma separated list of elements, surrounded by
1822 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1823 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1824 href="#t_vector">vector type</a>, and the number and types of elements must
1825 match those specified by the type.
1826 </dd>
1827
1828 <dt><b>Zero initialization</b></dt>
1829
1830 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1831 value to zero of <em>any</em> type, including scalar and aggregate types.
1832 This is often used to avoid having to print large zero initializers (e.g. for
1833 large arrays) and is always exactly equivalent to using explicit zero
1834 initializers.
1835 </dd>
1836</dl>
1837
1838</div>
1839
1840<!-- ======================================================================= -->
1841<div class="doc_subsection">
1842 <a name="globalconstants">Global Variable and Function Addresses</a>
1843</div>
1844
1845<div class="doc_text">
1846
1847<p>The addresses of <a href="#globalvars">global variables</a> and <a
1848href="#functionstructure">functions</a> are always implicitly valid (link-time)
1849constants. These constants are explicitly referenced when the <a
1850href="#identifiers">identifier for the global</a> is used and always have <a
1851href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1852file:</p>
1853
1854<div class="doc_code">
1855<pre>
1856@X = global i32 17
1857@Y = global i32 42
1858@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1859</pre>
1860</div>
1861
1862</div>
1863
1864<!-- ======================================================================= -->
1865<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1866<div class="doc_text">
1867 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1868 no specific value. Undefined values may be of any type and be used anywhere
1869 a constant is permitted.</p>
1870
1871 <p>Undefined values indicate to the compiler that the program is well defined
1872 no matter what value is used, giving the compiler more freedom to optimize.
1873 </p>
1874</div>
1875
1876<!-- ======================================================================= -->
1877<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1878</div>
1879
1880<div class="doc_text">
1881
1882<p>Constant expressions are used to allow expressions involving other constants
1883to be used as constants. Constant expressions may be of any <a
1884href="#t_firstclass">first class</a> type and may involve any LLVM operation
1885that does not have side effects (e.g. load and call are not supported). The
1886following is the syntax for constant expressions:</p>
1887
1888<dl>
1889 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1890 <dd>Truncate a constant to another type. The bit size of CST must be larger
1891 than the bit size of TYPE. Both types must be integers.</dd>
1892
1893 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1894 <dd>Zero extend a constant to another type. The bit size of CST must be
1895 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1896
1897 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1898 <dd>Sign extend a constant to another type. The bit size of CST must be
1899 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1900
1901 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1902 <dd>Truncate a floating point constant to another floating point type. The
1903 size of CST must be larger than the size of TYPE. Both types must be
1904 floating point.</dd>
1905
1906 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1907 <dd>Floating point extend a constant to another type. The size of CST must be
1908 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1909
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1910 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1911 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1912 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1913 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1914 of the same number of elements. If the value won't fit in the integer type,
1915 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1916
1917 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1918 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1919 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1920 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1921 of the same number of elements. If the value won't fit in the integer type,
1922 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1923
1924 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1925 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1926 constant. TYPE must be a scalar or vector floating point type. CST must be of
1927 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1928 of the same number of elements. If the value won't fit in the floating point
1929 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1930
1931 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1932 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1933 constant. TYPE must be a scalar or vector floating point type. CST must be of
1934 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1935 of the same number of elements. If the value won't fit in the floating point
1936 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1937
1938 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1939 <dd>Convert a pointer typed constant to the corresponding integer constant
1940 TYPE must be an integer type. CST must be of pointer type. The CST value is
1941 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1942
1943 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1944 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1945 pointer type. CST must be of integer type. The CST value is zero extended,
1946 truncated, or unchanged to make it fit in a pointer size. This one is
1947 <i>really</i> dangerous!</dd>
1948
1949 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1950 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1951 identical (same number of bits). The conversion is done as if the CST value
1952 was stored to memory and read back as TYPE. In other words, no bits change
1953 with this operator, just the type. This can be used for conversion of
1954 vector types to any other type, as long as they have the same bit width. For
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]1955 pointers it is only valid to cast to another pointer type. It is not valid
1956 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1957 </dd>
1958
1959 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1960
1961 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1962 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1963 instruction, the index list may have zero or more indexes, which are required
1964 to make sense for the type of "CSTPTR".</dd>
1965
1966 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1967
1968 <dd>Perform the <a href="#i_select">select operation</a> on
1969 constants.</dd>
1970
1971 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1972 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1973
1974 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1975 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1976
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1977 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1978 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1979
1980 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1981 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1982
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1984
1985 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1986 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1987
1988 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1989
1990 <dd>Perform the <a href="#i_insertelement">insertelement
1991 operation</a> on constants.</dd>
1992
1993
1994 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1995
1996 <dd>Perform the <a href="#i_shufflevector">shufflevector
1997 operation</a> on constants.</dd>
1998
1999 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2000
2001 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2002 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2003 binary</a> operations. The constraints on operands are the same as those for
2004 the corresponding instruction (e.g. no bitwise operations on floating point
2005 values are allowed).</dd>
2006</dl>
2007</div>
2008
2009<!-- *********************************************************************** -->
2010<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2011<!-- *********************************************************************** -->
2012
2013<!-- ======================================================================= -->
2014<div class="doc_subsection">
2015<a name="inlineasm">Inline Assembler Expressions</a>
2016</div>
2017
2018<div class="doc_text">
2019
2020<p>
2021LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2022Module-Level Inline Assembly</a>) through the use of a special value. This
2023value represents the inline assembler as a string (containing the instructions
2024to emit), a list of operand constraints (stored as a string), and a flag that
2025indicates whether or not the inline asm expression has side effects. An example
2026inline assembler expression is:
2027</p>
2028
2029<div class="doc_code">
2030<pre>
2031i32 (i32) asm "bswap $0", "=r,r"
2032</pre>
2033</div>
2034
2035<p>
2036Inline assembler expressions may <b>only</b> be used as the callee operand of
2037a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2038</p>
2039
2040<div class="doc_code">
2041<pre>
2042%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2043</pre>
2044</div>
2045
2046<p>
2047Inline asms with side effects not visible in the constraint list must be marked
2048as having side effects. This is done through the use of the
2049'<tt>sideeffect</tt>' keyword, like so:
2050</p>
2051
2052<div class="doc_code">
2053<pre>
2054call void asm sideeffect "eieio", ""()
2055</pre>
2056</div>
2057
2058<p>TODO: The format of the asm and constraints string still need to be
2059documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2060need to be documented). This is probably best done by reference to another
2061document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2062</p>
2063
2064</div>
2065
2066<!-- *********************************************************************** -->
2067<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2068<!-- *********************************************************************** -->
2069
2070<div class="doc_text">
2071
2072<p>The LLVM instruction set consists of several different
2073classifications of instructions: <a href="#terminators">terminator
2074instructions</a>, <a href="#binaryops">binary instructions</a>,
2075<a href="#bitwiseops">bitwise binary instructions</a>, <a
2076 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2077instructions</a>.</p>
2078
2079</div>
2080
2081<!-- ======================================================================= -->
2082<div class="doc_subsection"> <a name="terminators">Terminator
2083Instructions</a> </div>
2084
2085<div class="doc_text">
2086
2087<p>As mentioned <a href="#functionstructure">previously</a>, every
2088basic block in a program ends with a "Terminator" instruction, which
2089indicates which block should be executed after the current block is
2090finished. These terminator instructions typically yield a '<tt>void</tt>'
2091value: they produce control flow, not values (the one exception being
2092the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2093<p>There are six different terminator instructions: the '<a
2094 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2095instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2096the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2097 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2098 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2099
2100</div>
2101
2102<!-- _______________________________________________________________________ -->
2103<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2104Instruction</a> </div>
2105<div class="doc_text">
2106<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2107<pre>
2108 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]2109 ret void <i>; Return from void function</i>
2110</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2111
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2112<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2113
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2114<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2115optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2116<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2117returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2118control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2119
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2120<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2121
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2122<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2123the return value. The type of the return value must be a
2124'<a href="#t_firstclass">first class</a>' type.</p>
2125
2126<p>A function is not <a href="#wellformed">well formed</a> if
2127it it has a non-void return type and contains a '<tt>ret</tt>'
2128instruction with no return value or a return value with a type that
2129does not match its type, or if it has a void return type and contains
2130a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2131
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2132<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2134<p>When the '<tt>ret</tt>' instruction is executed, control flow
2135returns back to the calling function's context. If the caller is a "<a
2136 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2137the instruction after the call. If the caller was an "<a
2138 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2139at the beginning of the "normal" destination block. If the instruction
2140returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2141return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2142
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2143<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2144
2145<pre>
2146 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2147 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2148 ret { i32, i8 } { i32 4, i8 2 } <i>; Return an aggregate of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2149</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2150
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2151<p>Note that the code generator does not yet fully support large
2152 return values. The specific sizes that are currently supported are
2153 dependent on the target. For integers, on 32-bit targets the limit
2154 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2155 For aggregate types, the current limits are dependent on the element
2156 types; for example targets are often limited to 2 total integer
2157 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2158
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2159</div>
2160<!-- _______________________________________________________________________ -->
2161<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2162<div class="doc_text">
2163<h5>Syntax:</h5>
2164<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2165</pre>
2166<h5>Overview:</h5>
2167<p>The '<tt>br</tt>' instruction is used to cause control flow to
2168transfer to a different basic block in the current function. There are
2169two forms of this instruction, corresponding to a conditional branch
2170and an unconditional branch.</p>
2171<h5>Arguments:</h5>
2172<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2173single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2174unconditional form of the '<tt>br</tt>' instruction takes a single
2175'<tt>label</tt>' value as a target.</p>
2176<h5>Semantics:</h5>
2177<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2178argument is evaluated. If the value is <tt>true</tt>, control flows
2179to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2180control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2181<h5>Example:</h5>
2182<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
2183 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2184</div>
2185<!-- _______________________________________________________________________ -->
2186<div class="doc_subsubsection">
2187 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2188</div>
2189
2190<div class="doc_text">
2191<h5>Syntax:</h5>
2192
2193<pre>
2194 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2195</pre>
2196
2197<h5>Overview:</h5>
2198
2199<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2200several different places. It is a generalization of the '<tt>br</tt>'
2201instruction, allowing a branch to occur to one of many possible
2202destinations.</p>
2203
2204
2205<h5>Arguments:</h5>
2206
2207<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2208comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2209an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2210table is not allowed to contain duplicate constant entries.</p>
2211
2212<h5>Semantics:</h5>
2213
2214<p>The <tt>switch</tt> instruction specifies a table of values and
2215destinations. When the '<tt>switch</tt>' instruction is executed, this
2216table is searched for the given value. If the value is found, control flow is
2217transfered to the corresponding destination; otherwise, control flow is
2218transfered to the default destination.</p>
2219
2220<h5>Implementation:</h5>
2221
2222<p>Depending on properties of the target machine and the particular
2223<tt>switch</tt> instruction, this instruction may be code generated in different
2224ways. For example, it could be generated as a series of chained conditional
2225branches or with a lookup table.</p>
2226
2227<h5>Example:</h5>
2228
2229<pre>
2230 <i>; Emulate a conditional br instruction</i>
2231 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2232 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2233
2234 <i>; Emulate an unconditional br instruction</i>
2235 switch i32 0, label %dest [ ]
2236
2237 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2238 switch i32 %val, label %otherwise [ i32 0, label %onzero
2239 i32 1, label %onone
2240 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2241</pre>
2242</div>
2243
2244<!-- _______________________________________________________________________ -->
2245<div class="doc_subsubsection">
2246 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2247</div>
2248
2249<div class="doc_text">
2250
2251<h5>Syntax:</h5>
2252
2253<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2254 &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]2255 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2256</pre>
2257
2258<h5>Overview:</h5>
2259
2260<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2261function, with the possibility of control flow transfer to either the
2262'<tt>normal</tt>' label or the
2263'<tt>exception</tt>' label. If the callee function returns with the
2264"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2265"normal" label. If the callee (or any indirect callees) returns with the "<a
2266href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2267continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2268
2269<h5>Arguments:</h5>
2270
2271<p>This instruction requires several arguments:</p>
2272
2273<ol>
2274 <li>
2275 The optional "cconv" marker indicates which <a href="#callingconv">calling
2276 convention</a> the call should use. If none is specified, the call defaults
2277 to using C calling conventions.
2278 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2279
2280 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2281 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2282 and '<tt>inreg</tt>' attributes are valid here.</li>
2283
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2284 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2285 function value being invoked. In most cases, this is a direct function
2286 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2287 an arbitrary pointer to function value.
2288 </li>
2289
2290 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2291 function to be invoked. </li>
2292
2293 <li>'<tt>function args</tt>': argument list whose types match the function
2294 signature argument types. If the function signature indicates the function
2295 accepts a variable number of arguments, the extra arguments can be
2296 specified. </li>
2297
2298 <li>'<tt>normal label</tt>': the label reached when the called function
2299 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2300
2301 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2302 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2303
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2304 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2305 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2306 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2307</ol>
2308
2309<h5>Semantics:</h5>
2310
2311<p>This instruction is designed to operate as a standard '<tt><a
2312href="#i_call">call</a></tt>' instruction in most regards. The primary
2313difference is that it establishes an association with a label, which is used by
2314the runtime library to unwind the stack.</p>
2315
2316<p>This instruction is used in languages with destructors to ensure that proper
2317cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2318exception. Additionally, this is important for implementation of
2319'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2320
2321<h5>Example:</h5>
2322<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2323 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2324 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2325 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2326 unwind label %TestCleanup <i>; {i32}:retval set</i>
2327</pre>
2328</div>
2329
2330
2331<!-- _______________________________________________________________________ -->
2332
2333<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2334Instruction</a> </div>
2335
2336<div class="doc_text">
2337
2338<h5>Syntax:</h5>
2339<pre>
2340 unwind
2341</pre>
2342
2343<h5>Overview:</h5>
2344
2345<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2346at the first callee in the dynamic call stack which used an <a
2347href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2348primarily used to implement exception handling.</p>
2349
2350<h5>Semantics:</h5>
2351
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2352<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2353immediately halt. The dynamic call stack is then searched for the first <a
2354href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2355execution continues at the "exceptional" destination block specified by the
2356<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2357dynamic call chain, undefined behavior results.</p>
2358</div>
2359
2360<!-- _______________________________________________________________________ -->
2361
2362<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2363Instruction</a> </div>
2364
2365<div class="doc_text">
2366
2367<h5>Syntax:</h5>
2368<pre>
2369 unreachable
2370</pre>
2371
2372<h5>Overview:</h5>
2373
2374<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2375instruction is used to inform the optimizer that a particular portion of the
2376code is not reachable. This can be used to indicate that the code after a
2377no-return function cannot be reached, and other facts.</p>
2378
2379<h5>Semantics:</h5>
2380
2381<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2382</div>
2383
2384
2385
2386<!-- ======================================================================= -->
2387<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2388<div class="doc_text">
2389<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2390program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2391produce a single value. The operands might represent
2392multiple 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]2393The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2394<p>There are several different binary operators:</p>
2395</div>
2396<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2397<div class="doc_subsubsection">
2398 <a name="i_add">'<tt>add</tt>' Instruction</a>
2399</div>
2400
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2401<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2403<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2404
2405<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2406 &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]2407</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2409<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2411<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2413<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2414
2415<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2416 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2417 <a href="#t_vector">vector</a> values. Both arguments must have identical
2418 types.</p>
2419
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2420<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2422<p>The value produced is the integer or floating point sum of the two
2423operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2424
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2425<p>If an integer sum has unsigned overflow, the result returned is the
2426mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2427the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2428
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2429<p>Because LLVM integers use a two's complement representation, this
2430instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2432<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2433
2434<pre>
2435 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2436</pre>
2437</div>
2438<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2439<div class="doc_subsubsection">
2440 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2441</div>
2442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2443<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2445<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2446
2447<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2448 &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]2449</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2450
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2451<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2452
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2453<p>The '<tt>sub</tt>' instruction returns the difference of its two
2454operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2455
2456<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2457'<tt>neg</tt>' instruction present in most other intermediate
2458representations.</p>
2459
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2460<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2461
2462<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2463 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2464 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2465 types.</p>
2466
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2467<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2469<p>The value produced is the integer or floating point difference of
2470the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2471
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2472<p>If an integer difference has unsigned overflow, the result returned is the
2473mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2474the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2475
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2476<p>Because LLVM integers use a two's complement representation, this
2477instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2479<h5>Example:</h5>
2480<pre>
2481 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2482 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2483</pre>
2484</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2486<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487<div class="doc_subsubsection">
2488 <a name="i_mul">'<tt>mul</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>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2494<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]2495</pre>
2496<h5>Overview:</h5>
2497<p>The '<tt>mul</tt>' instruction returns the product of its two
2498operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2499
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2500<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2501
2502<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2503href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2504or <a href="#t_vector">vector</a> values. Both arguments must have identical
2505types.</p>
2506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2507<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2509<p>The value produced is the integer or floating point product of the
2510two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2511
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2512<p>If the result of an integer multiplication has unsigned overflow,
2513the result returned is the mathematical result modulo
25142<sup>n</sup>, where n is the bit width of the result.</p>
2515<p>Because LLVM integers use a two's complement representation, and the
2516result is the same width as the operands, this instruction returns the
2517correct result for both signed and unsigned integers. If a full product
2518(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2519should be sign-extended or zero-extended as appropriate to the
2520width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2521<h5>Example:</h5>
2522<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2523</pre>
2524</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2525
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2526<!-- _______________________________________________________________________ -->
2527<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2528</a></div>
2529<div class="doc_text">
2530<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2531<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]2532</pre>
2533<h5>Overview:</h5>
2534<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2535operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2536
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2537<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2538
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2539<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2540<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2541values. Both arguments must have identical types.</p>
2542
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2543<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2544
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2545<p>The value produced is the unsigned integer quotient of the two operands.</p>
2546<p>Note that unsigned integer division and signed integer division are distinct
2547operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2548<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2549<h5>Example:</h5>
2550<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2551</pre>
2552</div>
2553<!-- _______________________________________________________________________ -->
2554<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2555</a> </div>
2556<div class="doc_text">
2557<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2558<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2559 &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]2560</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2562<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2563
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2564<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2565operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2566
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2567<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2568
2569<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2570<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2571values. Both arguments must have identical types.</p>
2572
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2573<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2574<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]2575<p>Note that signed integer division and unsigned integer division are distinct
2576operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2577<p>Division by zero leads to undefined behavior. Overflow also leads to
2578undefined behavior; this is a rare case, but can occur, for example,
2579by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580<h5>Example:</h5>
2581<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2582</pre>
2583</div>
2584<!-- _______________________________________________________________________ -->
2585<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2586Instruction</a> </div>
2587<div class="doc_text">
2588<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2589<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2590 &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]2591</pre>
2592<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2595operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597<h5>Arguments:</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 two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2600<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2601of floating point values. Both arguments must have identical types.</p>
2602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2603<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2604
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2605<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2606
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2607<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2608
2609<pre>
2610 &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]2611</pre>
2612</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<!-- _______________________________________________________________________ -->
2615<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2616</div>
2617<div class="doc_text">
2618<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2619<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]2620</pre>
2621<h5>Overview:</h5>
2622<p>The '<tt>urem</tt>' instruction returns the remainder from the
2623unsigned division of its two arguments.</p>
2624<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2625<p>The two arguments to the '<tt>urem</tt>' instruction must be
2626<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2627values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2628<h5>Semantics:</h5>
2629<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2630This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2631<p>Note that unsigned integer remainder and signed integer remainder are
2632distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2633<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2634<h5>Example:</h5>
2635<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2636</pre>
2637
2638</div>
2639<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2640<div class="doc_subsubsection">
2641 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2642</div>
2643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2644<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2645
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2646<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2647
2648<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2649 &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]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>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2655signed division of its two operands. This instruction can also take
2656<a href="#t_vector">vector</a> versions of the values in which case
2657the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2658
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2660
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2661<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2662<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2663values. Both arguments must have identical types.</p>
2664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2665<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2666
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2668has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2669operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670a value. For more information about the difference, see <a
2671 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2672Math Forum</a>. For a table of how this is implemented in various languages,
2673please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2674Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2675<p>Note that signed integer remainder and unsigned integer remainder are
2676distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2677<p>Taking the remainder of a division by zero leads to undefined behavior.
2678Overflow also leads to undefined behavior; this is a rare case, but can occur,
2679for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2680(The remainder doesn't actually overflow, but this rule lets srem be
2681implemented using instructions that return both the result of the division
2682and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2683<h5>Example:</h5>
2684<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2685</pre>
2686
2687</div>
2688<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2689<div class="doc_subsubsection">
2690 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2691
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2692<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2693
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2694<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2695<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]2696</pre>
2697<h5>Overview:</h5>
2698<p>The '<tt>frem</tt>' instruction returns the remainder from the
2699division of its two operands.</p>
2700<h5>Arguments:</h5>
2701<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2702<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2703of floating point values. Both arguments must have identical types.</p>
2704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2705<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2706
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2707<p>This instruction returns the <i>remainder</i> of a division.
2708The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2710<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2711
2712<pre>
2713 &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]2714</pre>
2715</div>
2716
2717<!-- ======================================================================= -->
2718<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2719Operations</a> </div>
2720<div class="doc_text">
2721<p>Bitwise binary operators are used to do various forms of
2722bit-twiddling in a program. They are generally very efficient
2723instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2724instructions. They require two operands of the same type, execute an operation on them,
2725and 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]2726</div>
2727
2728<!-- _______________________________________________________________________ -->
2729<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2730Instruction</a> </div>
2731<div class="doc_text">
2732<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2733<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]2734</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2739the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2740
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2741<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2742
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2743<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2744 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2745type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2746
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2748
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2749<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2750where 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]2751equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2752If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2753corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2754
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2755<h5>Example:</h5><pre>
2756 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2757 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2758 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2759 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2760 &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]2761</pre>
2762</div>
2763<!-- _______________________________________________________________________ -->
2764<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2765Instruction</a> </div>
2766<div class="doc_text">
2767<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2768<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]2769</pre>
2770
2771<h5>Overview:</h5>
2772<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2773operand shifted to the right a specified number of bits with zero fill.</p>
2774
2775<h5>Arguments:</h5>
2776<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2777<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]2778type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2779
2780<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2781
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2782<p>This instruction always performs a logical shift right operation. The most
2783significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2784shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2785the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2786vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2787amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2788
2789<h5>Example:</h5>
2790<pre>
2791 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2792 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2793 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2794 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2795 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2796 &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]2797</pre>
2798</div>
2799
2800<!-- _______________________________________________________________________ -->
2801<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2802Instruction</a> </div>
2803<div class="doc_text">
2804
2805<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2806<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]2807</pre>
2808
2809<h5>Overview:</h5>
2810<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2811operand shifted to the right a specified number of bits with sign extension.</p>
2812
2813<h5>Arguments:</h5>
2814<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2815<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]2816type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2817
2818<h5>Semantics:</h5>
2819<p>This instruction always performs an arithmetic shift right operation,
2820The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2821of <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]2822larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2823arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2824corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2825
2826<h5>Example:</h5>
2827<pre>
2828 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2829 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2830 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2831 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2832 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2833 &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]2834</pre>
2835</div>
2836
2837<!-- _______________________________________________________________________ -->
2838<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2839Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2843<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2844
2845<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2846 &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]2847</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2849<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2851<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2852its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2855
2856<p>The two arguments to the '<tt>and</tt>' instruction must be
2857<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2858values. Both arguments must have identical types.</p>
2859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2860<h5>Semantics:</h5>
2861<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2862<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2863<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2864<table border="1" cellspacing="0" cellpadding="4">
2865 <tbody>
2866 <tr>
2867 <td>In0</td>
2868 <td>In1</td>
2869 <td>Out</td>
2870 </tr>
2871 <tr>
2872 <td>0</td>
2873 <td>0</td>
2874 <td>0</td>
2875 </tr>
2876 <tr>
2877 <td>0</td>
2878 <td>1</td>
2879 <td>0</td>
2880 </tr>
2881 <tr>
2882 <td>1</td>
2883 <td>0</td>
2884 <td>0</td>
2885 </tr>
2886 <tr>
2887 <td>1</td>
2888 <td>1</td>
2889 <td>1</td>
2890 </tr>
2891 </tbody>
2892</table>
2893</div>
2894<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2895<pre>
2896 &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]2897 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2898 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2899</pre>
2900</div>
2901<!-- _______________________________________________________________________ -->
2902<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2903<div class="doc_text">
2904<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2905<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]2906</pre>
2907<h5>Overview:</h5>
2908<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2909or of its two operands.</p>
2910<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2911
2912<p>The two arguments to the '<tt>or</tt>' instruction must be
2913<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2914values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2915<h5>Semantics:</h5>
2916<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2917<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2918<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2919<table border="1" cellspacing="0" cellpadding="4">
2920 <tbody>
2921 <tr>
2922 <td>In0</td>
2923 <td>In1</td>
2924 <td>Out</td>
2925 </tr>
2926 <tr>
2927 <td>0</td>
2928 <td>0</td>
2929 <td>0</td>
2930 </tr>
2931 <tr>
2932 <td>0</td>
2933 <td>1</td>
2934 <td>1</td>
2935 </tr>
2936 <tr>
2937 <td>1</td>
2938 <td>0</td>
2939 <td>1</td>
2940 </tr>
2941 <tr>
2942 <td>1</td>
2943 <td>1</td>
2944 <td>1</td>
2945 </tr>
2946 </tbody>
2947</table>
2948</div>
2949<h5>Example:</h5>
2950<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2951 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2952 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2953</pre>
2954</div>
2955<!-- _______________________________________________________________________ -->
2956<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2957Instruction</a> </div>
2958<div class="doc_text">
2959<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2960<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]2961</pre>
2962<h5>Overview:</h5>
2963<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2964or of its two operands. The <tt>xor</tt> is used to implement the
2965"one's complement" operation, which is the "~" operator in C.</p>
2966<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2967<p>The two arguments to the '<tt>xor</tt>' instruction must be
2968<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2969values. Both arguments must have identical types.</p>
2970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2971<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2972
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2973<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2974<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2975<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2976<table border="1" cellspacing="0" cellpadding="4">
2977 <tbody>
2978 <tr>
2979 <td>In0</td>
2980 <td>In1</td>
2981 <td>Out</td>
2982 </tr>
2983 <tr>
2984 <td>0</td>
2985 <td>0</td>
2986 <td>0</td>
2987 </tr>
2988 <tr>
2989 <td>0</td>
2990 <td>1</td>
2991 <td>1</td>
2992 </tr>
2993 <tr>
2994 <td>1</td>
2995 <td>0</td>
2996 <td>1</td>
2997 </tr>
2998 <tr>
2999 <td>1</td>
3000 <td>1</td>
3001 <td>0</td>
3002 </tr>
3003 </tbody>
3004</table>
3005</div>
3006<p> </p>
3007<h5>Example:</h5>
3008<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3009 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3010 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3011 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3012</pre>
3013</div>
3014
3015<!-- ======================================================================= -->
3016<div class="doc_subsection">
3017 <a name="vectorops">Vector Operations</a>
3018</div>
3019
3020<div class="doc_text">
3021
3022<p>LLVM supports several instructions to represent vector operations in a
3023target-independent manner. These instructions cover the element-access and
3024vector-specific operations needed to process vectors effectively. While LLVM
3025does directly support these vector operations, many sophisticated algorithms
3026will want to use target-specific intrinsics to take full advantage of a specific
3027target.</p>
3028
3029</div>
3030
3031<!-- _______________________________________________________________________ -->
3032<div class="doc_subsubsection">
3033 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3034</div>
3035
3036<div class="doc_text">
3037
3038<h5>Syntax:</h5>
3039
3040<pre>
3041 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3042</pre>
3043
3044<h5>Overview:</h5>
3045
3046<p>
3047The '<tt>extractelement</tt>' instruction extracts a single scalar
3048element from a vector at a specified index.
3049</p>
3050
3051
3052<h5>Arguments:</h5>
3053
3054<p>
3055The first operand of an '<tt>extractelement</tt>' instruction is a
3056value of <a href="#t_vector">vector</a> type. The second operand is
3057an index indicating the position from which to extract the element.
3058The index may be a variable.</p>
3059
3060<h5>Semantics:</h5>
3061
3062<p>
3063The result is a scalar of the same type as the element type of
3064<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3065<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3066results are undefined.
3067</p>
3068
3069<h5>Example:</h5>
3070
3071<pre>
3072 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3073</pre>
3074</div>
3075
3076
3077<!-- _______________________________________________________________________ -->
3078<div class="doc_subsubsection">
3079 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3080</div>
3081
3082<div class="doc_text">
3083
3084<h5>Syntax:</h5>
3085
3086<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3087 &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]3088</pre>
3089
3090<h5>Overview:</h5>
3091
3092<p>
3093The '<tt>insertelement</tt>' instruction inserts a scalar
3094element into a vector at a specified index.
3095</p>
3096
3097
3098<h5>Arguments:</h5>
3099
3100<p>
3101The first operand of an '<tt>insertelement</tt>' instruction is a
3102value of <a href="#t_vector">vector</a> type. The second operand is a
3103scalar value whose type must equal the element type of the first
3104operand. The third operand is an index indicating the position at
3105which to insert the value. The index may be a variable.</p>
3106
3107<h5>Semantics:</h5>
3108
3109<p>
3110The result is a vector of the same type as <tt>val</tt>. Its
3111element values are those of <tt>val</tt> except at position
3112<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3113exceeds the length of <tt>val</tt>, the results are undefined.
3114</p>
3115
3116<h5>Example:</h5>
3117
3118<pre>
3119 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3120</pre>
3121</div>
3122
3123<!-- _______________________________________________________________________ -->
3124<div class="doc_subsubsection">
3125 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3126</div>
3127
3128<div class="doc_text">
3129
3130<h5>Syntax:</h5>
3131
3132<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3133 &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]3134</pre>
3135
3136<h5>Overview:</h5>
3137
3138<p>
3139The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3140from two input vectors, returning a vector with the same element type as
3141the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3142</p>
3143
3144<h5>Arguments:</h5>
3145
3146<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3147The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3148with types that match each other. The third argument is a shuffle mask whose
3149element type is always 'i32'. The result of the instruction is a vector whose
3150length is the same as the shuffle mask and whose element type is the same as
3151the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3152</p>
3153
3154<p>
3155The shuffle mask operand is required to be a constant vector with either
3156constant integer or undef values.
3157</p>
3158
3159<h5>Semantics:</h5>
3160
3161<p>
3162The elements of the two input vectors are numbered from left to right across
3163both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3164the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3165gets. The element selector may be undef (meaning "don't care") and the second
3166operand may be undef if performing a shuffle from only one vector.
3167</p>
3168
3169<h5>Example:</h5>
3170
3171<pre>
3172 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3173 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3174 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3175 &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]3176 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3177 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3178 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3179 &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]3180</pre>
3181</div>
3182
3183
3184<!-- ======================================================================= -->
3185<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3186 <a name="aggregateops">Aggregate Operations</a>
3187</div>
3188
3189<div class="doc_text">
3190
3191<p>LLVM supports several instructions for working with aggregate values.
3192</p>
3193
3194</div>
3195
3196<!-- _______________________________________________________________________ -->
3197<div class="doc_subsubsection">
3198 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3199</div>
3200
3201<div class="doc_text">
3202
3203<h5>Syntax:</h5>
3204
3205<pre>
3206 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3207</pre>
3208
3209<h5>Overview:</h5>
3210
3211<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3212The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3213or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3214</p>
3215
3216
3217<h5>Arguments:</h5>
3218
3219<p>
3220The first operand of an '<tt>extractvalue</tt>' instruction is a
3221value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3222type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3223in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3224'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3225</p>
3226
3227<h5>Semantics:</h5>
3228
3229<p>
3230The result is the value at the position in the aggregate specified by
3231the index operands.
3232</p>
3233
3234<h5>Example:</h5>
3235
3236<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3237 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3238</pre>
3239</div>
3240
3241
3242<!-- _______________________________________________________________________ -->
3243<div class="doc_subsubsection">
3244 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3245</div>
3246
3247<div class="doc_text">
3248
3249<h5>Syntax:</h5>
3250
3251<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3252 &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]3253</pre>
3254
3255<h5>Overview:</h5>
3256
3257<p>
3258The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3259into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3260</p>
3261
3262
3263<h5>Arguments:</h5>
3264
3265<p>
3266The first operand of an '<tt>insertvalue</tt>' instruction is a
3267value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3268The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3269The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3270indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3271indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3272'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3273The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3274by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3275</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3276
3277<h5>Semantics:</h5>
3278
3279<p>
3280The result is an aggregate of the same type as <tt>val</tt>. Its
3281value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3282specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3283</p>
3284
3285<h5>Example:</h5>
3286
3287<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3288 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3289</pre>
3290</div>
3291
3292
3293<!-- ======================================================================= -->
3294<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3295 <a name="memoryops">Memory Access and Addressing Operations</a>
3296</div>
3297
3298<div class="doc_text">
3299
3300<p>A key design point of an SSA-based representation is how it
3301represents memory. In LLVM, no memory locations are in SSA form, which
3302makes things very simple. This section describes how to read, write,
3303allocate, and free memory in LLVM.</p>
3304
3305</div>
3306
3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection">
3309 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3310</div>
3311
3312<div class="doc_text">
3313
3314<h5>Syntax:</h5>
3315
3316<pre>
3317 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3318</pre>
3319
3320<h5>Overview:</h5>
3321
3322<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3323heap and returns a pointer to it. The object is always allocated in the generic
3324address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3325
3326<h5>Arguments:</h5>
3327
3328<p>The '<tt>malloc</tt>' instruction allocates
3329<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3330bytes of memory from the operating system and returns a pointer of the
3331appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3332number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3333If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3334be aligned to at least that boundary. If not specified, or if zero, the target can
3335choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3336
3337<p>'<tt>type</tt>' must be a sized type.</p>
3338
3339<h5>Semantics:</h5>
3340
3341<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3342a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3343result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344
3345<h5>Example:</h5>
3346
3347<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3348 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3349
3350 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3351 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3352 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3353 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3354 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3355</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3356
3357<p>Note that the code generator does not yet respect the
3358 alignment value.</p>
3359
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3360</div>
3361
3362<!-- _______________________________________________________________________ -->
3363<div class="doc_subsubsection">
3364 <a name="i_free">'<tt>free</tt>' Instruction</a>
3365</div>
3366
3367<div class="doc_text">
3368
3369<h5>Syntax:</h5>
3370
3371<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3372 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3373</pre>
3374
3375<h5>Overview:</h5>
3376
3377<p>The '<tt>free</tt>' instruction returns memory back to the unused
3378memory heap to be reallocated in the future.</p>
3379
3380<h5>Arguments:</h5>
3381
3382<p>'<tt>value</tt>' shall be a pointer value that points to a value
3383that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3384instruction.</p>
3385
3386<h5>Semantics:</h5>
3387
3388<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3389after this instruction executes. If the pointer is null, the operation
3390is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3391
3392<h5>Example:</h5>
3393
3394<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3395 %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]3396 free [4 x i8]* %array
3397</pre>
3398</div>
3399
3400<!-- _______________________________________________________________________ -->
3401<div class="doc_subsubsection">
3402 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3403</div>
3404
3405<div class="doc_text">
3406
3407<h5>Syntax:</h5>
3408
3409<pre>
3410 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3411</pre>
3412
3413<h5>Overview:</h5>
3414
3415<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3416currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3417returns to its caller. The object is always allocated in the generic address
3418space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3419
3420<h5>Arguments:</h5>
3421
3422<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3423bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3424appropriate type to the program. If "NumElements" is specified, it is the
3425number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3426If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3427to be aligned to at least that boundary. If not specified, or if zero, the target
3428can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3429
3430<p>'<tt>type</tt>' may be any sized type.</p>
3431
3432<h5>Semantics:</h5>
3433
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3434<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3435there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3436memory is automatically released when the function returns. The '<tt>alloca</tt>'
3437instruction is commonly used to represent automatic variables that must
3438have an address available. When the function returns (either with the <tt><a
3439 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]3440instructions), the memory is reclaimed. Allocating zero bytes
3441is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3442
3443<h5>Example:</h5>
3444
3445<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3446 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3447 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3448 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3449 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3450</pre>
3451</div>
3452
3453<!-- _______________________________________________________________________ -->
3454<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3455Instruction</a> </div>
3456<div class="doc_text">
3457<h5>Syntax:</h5>
3458<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>
3459<h5>Overview:</h5>
3460<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3461<h5>Arguments:</h5>
3462<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3463address from which to load. The pointer must point to a <a
3464 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3465marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3466the number or order of execution of this <tt>load</tt> with other
3467volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3468instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3469<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3470The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3471(that is, the alignment of the memory address). A value of 0 or an
3472omitted "align" argument means that the operation has the preferential
3473alignment for the target. It is the responsibility of the code emitter
3474to ensure that the alignment information is correct. Overestimating
3475the alignment results in an undefined behavior. Underestimating the
3476alignment may produce less efficient code. An alignment of 1 is always
3477safe.
3478</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3479<h5>Semantics:</h5>
3480<p>The location of memory pointed to is loaded.</p>
3481<h5>Examples:</h5>
3482<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3483 <a
3484 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3485 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3486</pre>
3487</div>
3488<!-- _______________________________________________________________________ -->
3489<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3490Instruction</a> </div>
3491<div class="doc_text">
3492<h5>Syntax:</h5>
3493<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3494 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3495</pre>
3496<h5>Overview:</h5>
3497<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3498<h5>Arguments:</h5>
3499<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3500to 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]3501operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3502of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3503operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3504optimizer is not allowed to modify the number or order of execution of
3505this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3506 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3507<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3508The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3509(that is, the alignment of the memory address). A value of 0 or an
3510omitted "align" argument means that the operation has the preferential
3511alignment for the target. It is the responsibility of the code emitter
3512to ensure that the alignment information is correct. Overestimating
3513the alignment results in an undefined behavior. Underestimating the
3514alignment may produce less efficient code. An alignment of 1 is always
3515safe.
3516</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3517<h5>Semantics:</h5>
3518<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3519at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3520<h5>Example:</h5>
3521<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3522 store i32 3, i32* %ptr <i>; yields {void}</i>
3523 %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]3524</pre>
3525</div>
3526
3527<!-- _______________________________________________________________________ -->
3528<div class="doc_subsubsection">
3529 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3530</div>
3531
3532<div class="doc_text">
3533<h5>Syntax:</h5>
3534<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3535 &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]3536</pre>
3537
3538<h5>Overview:</h5>
3539
3540<p>
3541The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3542subelement of an aggregate data structure. It performs address calculation only
3543and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3544
3545<h5>Arguments:</h5>
3546
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3547<p>The first argument is always a pointer, and forms the basis of the
3548calculation. The remaining arguments are indices, that indicate which of the
3549elements of the aggregate object are indexed. The interpretation of each index
3550is dependent on the type being indexed into. The first index always indexes the
3551pointer value given as the first argument, the second index indexes a value of
3552the type pointed to (not necessarily the value directly pointed to, since the
3553first index can be non-zero), etc. The first type indexed into must be a pointer
3554value, subsequent types can be arrays, vectors and structs. Note that subsequent
3555types being indexed into can never be pointers, since that would require loading
3556the pointer before continuing calculation.</p>
3557
3558<p>The type of each index argument depends on the type it is indexing into.
3559When indexing into a (packed) structure, only <tt>i32</tt> integer
3560<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3561only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3562will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3563
3564<p>For example, let's consider a C code fragment and how it gets
3565compiled to LLVM:</p>
3566
3567<div class="doc_code">
3568<pre>
3569struct RT {
3570 char A;
3571 int B[10][20];
3572 char C;
3573};
3574struct ST {
3575 int X;
3576 double Y;
3577 struct RT Z;
3578};
3579
3580int *foo(struct ST *s) {
3581 return &amp;s[1].Z.B[5][13];
3582}
3583</pre>
3584</div>
3585
3586<p>The LLVM code generated by the GCC frontend is:</p>
3587
3588<div class="doc_code">
3589<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3590%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3591%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592
3593define i32* %foo(%ST* %s) {
3594entry:
3595 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3596 ret i32* %reg
3597}
3598</pre>
3599</div>
3600
3601<h5>Semantics:</h5>
3602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3603<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3604type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3605}</tt>' type, a structure. The second index indexes into the third element of
3606the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3607i8 }</tt>' type, another structure. The third index indexes into the second
3608element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3609array. The two dimensions of the array are subscripted into, yielding an
3610'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3611to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3612
3613<p>Note that it is perfectly legal to index partially through a
3614structure, returning a pointer to an inner element. Because of this,
3615the LLVM code for the given testcase is equivalent to:</p>
3616
3617<pre>
3618 define i32* %foo(%ST* %s) {
3619 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3620 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3621 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3622 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3623 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3624 ret i32* %t5
3625 }
3626</pre>
3627
3628<p>Note that it is undefined to access an array out of bounds: array and
3629pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3630The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3631defined to be accessible as variable length arrays, which requires access
3632beyond the zero'th element.</p>
3633
3634<p>The getelementptr instruction is often confusing. For some more insight
3635into how it works, see <a href="GetElementPtr.html">the getelementptr
3636FAQ</a>.</p>
3637
3638<h5>Example:</h5>
3639
3640<pre>
3641 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3642 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3643 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3644 %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]3645 <i>; yields i8*:eptr</i>
3646 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3647</pre>
3648</div>
3649
3650<!-- ======================================================================= -->
3651<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3652</div>
3653<div class="doc_text">
3654<p>The instructions in this category are the conversion instructions (casting)
3655which all take a single operand and a type. They perform various bit conversions
3656on the operand.</p>
3657</div>
3658
3659<!-- _______________________________________________________________________ -->
3660<div class="doc_subsubsection">
3661 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3662</div>
3663<div class="doc_text">
3664
3665<h5>Syntax:</h5>
3666<pre>
3667 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3668</pre>
3669
3670<h5>Overview:</h5>
3671<p>
3672The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3673</p>
3674
3675<h5>Arguments:</h5>
3676<p>
3677The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3678be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3679and type of the result, which must be an <a href="#t_integer">integer</a>
3680type. The bit size of <tt>value</tt> must be larger than the bit size of
3681<tt>ty2</tt>. Equal sized types are not allowed.</p>
3682
3683<h5>Semantics:</h5>
3684<p>
3685The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3686and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3687larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3688It will always truncate bits.</p>
3689
3690<h5>Example:</h5>
3691<pre>
3692 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3693 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3694 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3695</pre>
3696</div>
3697
3698<!-- _______________________________________________________________________ -->
3699<div class="doc_subsubsection">
3700 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3701</div>
3702<div class="doc_text">
3703
3704<h5>Syntax:</h5>
3705<pre>
3706 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3707</pre>
3708
3709<h5>Overview:</h5>
3710<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3711<tt>ty2</tt>.</p>
3712
3713
3714<h5>Arguments:</h5>
3715<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3716<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3717also be of <a href="#t_integer">integer</a> type. The bit size of the
3718<tt>value</tt> must be smaller than the bit size of the destination type,
3719<tt>ty2</tt>.</p>
3720
3721<h5>Semantics:</h5>
3722<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3723bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3724
3725<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3726
3727<h5>Example:</h5>
3728<pre>
3729 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3730 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3731</pre>
3732</div>
3733
3734<!-- _______________________________________________________________________ -->
3735<div class="doc_subsubsection">
3736 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3737</div>
3738<div class="doc_text">
3739
3740<h5>Syntax:</h5>
3741<pre>
3742 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3743</pre>
3744
3745<h5>Overview:</h5>
3746<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3747
3748<h5>Arguments:</h5>
3749<p>
3750The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3751<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3752also be of <a href="#t_integer">integer</a> type. The bit size of the
3753<tt>value</tt> must be smaller than the bit size of the destination type,
3754<tt>ty2</tt>.</p>
3755
3756<h5>Semantics:</h5>
3757<p>
3758The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3759bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3760the type <tt>ty2</tt>.</p>
3761
3762<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3763
3764<h5>Example:</h5>
3765<pre>
3766 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3767 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3768</pre>
3769</div>
3770
3771<!-- _______________________________________________________________________ -->
3772<div class="doc_subsubsection">
3773 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3774</div>
3775
3776<div class="doc_text">
3777
3778<h5>Syntax:</h5>
3779
3780<pre>
3781 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3782</pre>
3783
3784<h5>Overview:</h5>
3785<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3786<tt>ty2</tt>.</p>
3787
3788
3789<h5>Arguments:</h5>
3790<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3791 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3792cast it to. The size of <tt>value</tt> must be larger than the size of
3793<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3794<i>no-op cast</i>.</p>
3795
3796<h5>Semantics:</h5>
3797<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3798<a href="#t_floating">floating point</a> type to a smaller
3799<a href="#t_floating">floating point</a> type. If the value cannot fit within
3800the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3801
3802<h5>Example:</h5>
3803<pre>
3804 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3805 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3806</pre>
3807</div>
3808
3809<!-- _______________________________________________________________________ -->
3810<div class="doc_subsubsection">
3811 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3812</div>
3813<div class="doc_text">
3814
3815<h5>Syntax:</h5>
3816<pre>
3817 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3818</pre>
3819
3820<h5>Overview:</h5>
3821<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3822floating point value.</p>
3823
3824<h5>Arguments:</h5>
3825<p>The '<tt>fpext</tt>' instruction takes a
3826<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3827and a <a href="#t_floating">floating point</a> type to cast it to. The source
3828type must be smaller than the destination type.</p>
3829
3830<h5>Semantics:</h5>
3831<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3832<a href="#t_floating">floating point</a> type to a larger
3833<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3834used to make a <i>no-op cast</i> because it always changes bits. Use
3835<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3836
3837<h5>Example:</h5>
3838<pre>
3839 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3840 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3841</pre>
3842</div>
3843
3844<!-- _______________________________________________________________________ -->
3845<div class="doc_subsubsection">
3846 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3847</div>
3848<div class="doc_text">
3849
3850<h5>Syntax:</h5>
3851<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3852 &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]3853</pre>
3854
3855<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3856<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3857unsigned integer equivalent of type <tt>ty2</tt>.
3858</p>
3859
3860<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3861<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]3862scalar or vector <a href="#t_floating">floating point</a> value, and a type
3863to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3864type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3865vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3866
3867<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3868<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3869<a href="#t_floating">floating point</a> operand into the nearest (rounding
3870towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3871the results are undefined.</p>
3872
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3873<h5>Example:</h5>
3874<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3875 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3876 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3877 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3878</pre>
3879</div>
3880
3881<!-- _______________________________________________________________________ -->
3882<div class="doc_subsubsection">
3883 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3884</div>
3885<div class="doc_text">
3886
3887<h5>Syntax:</h5>
3888<pre>
3889 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3890</pre>
3891
3892<h5>Overview:</h5>
3893<p>The '<tt>fptosi</tt>' instruction converts
3894<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3895</p>
3896
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3897<h5>Arguments:</h5>
3898<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]3899scalar or vector <a href="#t_floating">floating point</a> value, and a type
3900to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3901type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3902vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3903
3904<h5>Semantics:</h5>
3905<p>The '<tt>fptosi</tt>' instruction converts its
3906<a href="#t_floating">floating point</a> operand into the nearest (rounding
3907towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3908the results are undefined.</p>
3909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3910<h5>Example:</h5>
3911<pre>
3912 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3913 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3914 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3915</pre>
3916</div>
3917
3918<!-- _______________________________________________________________________ -->
3919<div class="doc_subsubsection">
3920 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3921</div>
3922<div class="doc_text">
3923
3924<h5>Syntax:</h5>
3925<pre>
3926 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3927</pre>
3928
3929<h5>Overview:</h5>
3930<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3931integer and converts that value to the <tt>ty2</tt> type.</p>
3932
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3933<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3934<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3935scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3936to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3937type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3938floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3939
3940<h5>Semantics:</h5>
3941<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3942integer quantity and converts it to the corresponding floating point value. If
3943the value cannot fit in the floating point value, the results are undefined.</p>
3944
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3945<h5>Example:</h5>
3946<pre>
3947 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3948 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949</pre>
3950</div>
3951
3952<!-- _______________________________________________________________________ -->
3953<div class="doc_subsubsection">
3954 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3955</div>
3956<div class="doc_text">
3957
3958<h5>Syntax:</h5>
3959<pre>
3960 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3961</pre>
3962
3963<h5>Overview:</h5>
3964<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3965integer and converts that value to the <tt>ty2</tt> type.</p>
3966
3967<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3968<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3969scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3970to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3971type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3972floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3973
3974<h5>Semantics:</h5>
3975<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3976integer quantity and converts it to the corresponding floating point value. If
3977the value cannot fit in the floating point value, the results are undefined.</p>
3978
3979<h5>Example:</h5>
3980<pre>
3981 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3982 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3983</pre>
3984</div>
3985
3986<!-- _______________________________________________________________________ -->
3987<div class="doc_subsubsection">
3988 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3989</div>
3990<div class="doc_text">
3991
3992<h5>Syntax:</h5>
3993<pre>
3994 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3995</pre>
3996
3997<h5>Overview:</h5>
3998<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3999the integer type <tt>ty2</tt>.</p>
4000
4001<h5>Arguments:</h5>
4002<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4003must 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]4004<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]4005
4006<h5>Semantics:</h5>
4007<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4008<tt>ty2</tt> by interpreting the pointer value as an integer and either
4009truncating or zero extending that value to the size of the integer type. If
4010<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4011<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4012are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4013change.</p>
4014
4015<h5>Example:</h5>
4016<pre>
4017 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4018 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4019</pre>
4020</div>
4021
4022<!-- _______________________________________________________________________ -->
4023<div class="doc_subsubsection">
4024 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4025</div>
4026<div class="doc_text">
4027
4028<h5>Syntax:</h5>
4029<pre>
4030 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4031</pre>
4032
4033<h5>Overview:</h5>
4034<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4035a pointer type, <tt>ty2</tt>.</p>
4036
4037<h5>Arguments:</h5>
4038<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4039value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4040<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041
4042<h5>Semantics:</h5>
4043<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4044<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4045the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4046size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4047the size of a pointer then a zero extension is done. If they are the same size,
4048nothing is done (<i>no-op cast</i>).</p>
4049
4050<h5>Example:</h5>
4051<pre>
4052 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4053 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4054 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4055</pre>
4056</div>
4057
4058<!-- _______________________________________________________________________ -->
4059<div class="doc_subsubsection">
4060 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4061</div>
4062<div class="doc_text">
4063
4064<h5>Syntax:</h5>
4065<pre>
4066 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4067</pre>
4068
4069<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4071<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4072<tt>ty2</tt> without changing any bits.</p>
4073
4074<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4075
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4077a non-aggregate first class value, and a type to cast it to, which must also be
4078a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4079<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4081type is a pointer, the destination type must also be a pointer. This
4082instruction supports bitwise conversion of vectors to integers and to vectors
4083of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084
4085<h5>Semantics:</h5>
4086<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4087<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4088this conversion. The conversion is done as if the <tt>value</tt> had been
4089stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4090converted to other pointer types with this instruction. To convert pointers to
4091other types, use the <a href="#i_inttoptr">inttoptr</a> or
4092<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4093
4094<h5>Example:</h5>
4095<pre>
4096 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4097 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4098 %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]4099</pre>
4100</div>
4101
4102<!-- ======================================================================= -->
4103<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4104<div class="doc_text">
4105<p>The instructions in this category are the "miscellaneous"
4106instructions, which defy better classification.</p>
4107</div>
4108
4109<!-- _______________________________________________________________________ -->
4110<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4111</div>
4112<div class="doc_text">
4113<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4114<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]4115</pre>
4116<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4117<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4118a vector of boolean values based on comparison
4119of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120<h5>Arguments:</h5>
4121<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4122the condition code indicating the kind of comparison to perform. It is not
4123a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4124</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4125<ol>
4126 <li><tt>eq</tt>: equal</li>
4127 <li><tt>ne</tt>: not equal </li>
4128 <li><tt>ugt</tt>: unsigned greater than</li>
4129 <li><tt>uge</tt>: unsigned greater or equal</li>
4130 <li><tt>ult</tt>: unsigned less than</li>
4131 <li><tt>ule</tt>: unsigned less or equal</li>
4132 <li><tt>sgt</tt>: signed greater than</li>
4133 <li><tt>sge</tt>: signed greater or equal</li>
4134 <li><tt>slt</tt>: signed less than</li>
4135 <li><tt>sle</tt>: signed less or equal</li>
4136</ol>
4137<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4138<a href="#t_pointer">pointer</a>
4139or integer <a href="#t_vector">vector</a> typed.
4140They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4142<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]4143the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4144yields 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]4145</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4146<ol>
4147 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4148 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4149 </li>
4150 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4151 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4152 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4153 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4154 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4155 <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]4156 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4157 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4158 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4159 <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]4160 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4161 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4162 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4163 <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]4164 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4165 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4166 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4167 <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]4168</ol>
4169<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4170values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4171<p>If the operands are integer vectors, then they are compared
4172element by element. The result is an <tt>i1</tt> vector with
4173the same number of elements as the values being compared.
4174Otherwise, the result is an <tt>i1</tt>.
4175</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4176
4177<h5>Example:</h5>
4178<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4179 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4180 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4181 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4182 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4183 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4184</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4185
4186<p>Note that the code generator does not yet support vector types with
4187 the <tt>icmp</tt> instruction.</p>
4188
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4189</div>
4190
4191<!-- _______________________________________________________________________ -->
4192<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4193</div>
4194<div class="doc_text">
4195<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4196<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]4197</pre>
4198<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4199<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4200or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4201of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4202<p>
4203If the operands are floating point scalars, then the result
4204type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4205</p>
4206<p>If the operands are floating point vectors, then the result type
4207is a vector of boolean with the same number of elements as the
4208operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4209<h5>Arguments:</h5>
4210<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4211the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4212a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4213<ol>
4214 <li><tt>false</tt>: no comparison, always returns false</li>
4215 <li><tt>oeq</tt>: ordered and equal</li>
4216 <li><tt>ogt</tt>: ordered and greater than </li>
4217 <li><tt>oge</tt>: ordered and greater than or equal</li>
4218 <li><tt>olt</tt>: ordered and less than </li>
4219 <li><tt>ole</tt>: ordered and less than or equal</li>
4220 <li><tt>one</tt>: ordered and not equal</li>
4221 <li><tt>ord</tt>: ordered (no nans)</li>
4222 <li><tt>ueq</tt>: unordered or equal</li>
4223 <li><tt>ugt</tt>: unordered or greater than </li>
4224 <li><tt>uge</tt>: unordered or greater than or equal</li>
4225 <li><tt>ult</tt>: unordered or less than </li>
4226 <li><tt>ule</tt>: unordered or less than or equal</li>
4227 <li><tt>une</tt>: unordered or not equal</li>
4228 <li><tt>uno</tt>: unordered (either nans)</li>
4229 <li><tt>true</tt>: no comparison, always returns true</li>
4230</ol>
4231<p><i>Ordered</i> means that neither operand is a QNAN while
4232<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4233<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4234either a <a href="#t_floating">floating point</a> type
4235or a <a href="#t_vector">vector</a> of floating point type.
4236They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4237<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4238<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4239according to the condition code given as <tt>cond</tt>.
4240If the operands are vectors, then the vectors are compared
4241element by element.
4242Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4243always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4244<ol>
4245 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4246 <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]4247 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4248 <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]4249 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4250 <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]4251 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4252 <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]4253 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4254 <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]4255 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4256 <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]4257 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4259 <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]4260 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4261 <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]4262 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4263 <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]4264 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4265 <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]4266 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4267 <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]4268 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4269 <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]4270 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4271 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4272 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4273</ol>
4274
4275<h5>Example:</h5>
4276<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]4277 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4278 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4279 &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]4280</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4281
4282<p>Note that the code generator does not yet support vector types with
4283 the <tt>fcmp</tt> instruction.</p>
4284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4285</div>
4286
4287<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4288<div class="doc_subsubsection">
4289 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4290</div>
4291<div class="doc_text">
4292<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4293<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]4294</pre>
4295<h5>Overview:</h5>
4296<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4297element-wise comparison of its two integer vector operands.</p>
4298<h5>Arguments:</h5>
4299<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4300the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4301a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4302<ol>
4303 <li><tt>eq</tt>: equal</li>
4304 <li><tt>ne</tt>: not equal </li>
4305 <li><tt>ugt</tt>: unsigned greater than</li>
4306 <li><tt>uge</tt>: unsigned greater or equal</li>
4307 <li><tt>ult</tt>: unsigned less than</li>
4308 <li><tt>ule</tt>: unsigned less or equal</li>
4309 <li><tt>sgt</tt>: signed greater than</li>
4310 <li><tt>sge</tt>: signed greater or equal</li>
4311 <li><tt>slt</tt>: signed less than</li>
4312 <li><tt>sle</tt>: signed less or equal</li>
4313</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4314<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4315<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4316<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4317<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4318according to the condition code given as <tt>cond</tt>. The comparison yields a
4319<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4320identical type as the values being compared. The most significant bit in each
4321element is 1 if the element-wise comparison evaluates to true, and is 0
4322otherwise. All other bits of the result are undefined. The condition codes
4323are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4324instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4325
4326<h5>Example:</h5>
4327<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4328 &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>
4329 &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]4330</pre>
4331</div>
4332
4333<!-- _______________________________________________________________________ -->
4334<div class="doc_subsubsection">
4335 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4336</div>
4337<div class="doc_text">
4338<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4339<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]4340<h5>Overview:</h5>
4341<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4342element-wise comparison of its two floating point vector operands. The output
4343elements have the same width as the input elements.</p>
4344<h5>Arguments:</h5>
4345<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4346the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4347a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4348<ol>
4349 <li><tt>false</tt>: no comparison, always returns false</li>
4350 <li><tt>oeq</tt>: ordered and equal</li>
4351 <li><tt>ogt</tt>: ordered and greater than </li>
4352 <li><tt>oge</tt>: ordered and greater than or equal</li>
4353 <li><tt>olt</tt>: ordered and less than </li>
4354 <li><tt>ole</tt>: ordered and less than or equal</li>
4355 <li><tt>one</tt>: ordered and not equal</li>
4356 <li><tt>ord</tt>: ordered (no nans)</li>
4357 <li><tt>ueq</tt>: unordered or equal</li>
4358 <li><tt>ugt</tt>: unordered or greater than </li>
4359 <li><tt>uge</tt>: unordered or greater than or equal</li>
4360 <li><tt>ult</tt>: unordered or less than </li>
4361 <li><tt>ule</tt>: unordered or less than or equal</li>
4362 <li><tt>une</tt>: unordered or not equal</li>
4363 <li><tt>uno</tt>: unordered (either nans)</li>
4364 <li><tt>true</tt>: no comparison, always returns true</li>
4365</ol>
4366<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4367<a href="#t_floating">floating point</a> typed. They must also be identical
4368types.</p>
4369<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4370<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4371according to the condition code given as <tt>cond</tt>. The comparison yields a
4372<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4373an identical number of elements as the values being compared, and each element
4374having identical with to the width of the floating point elements. The most
4375significant bit in each element is 1 if the element-wise comparison evaluates to
4376true, and is 0 otherwise. All other bits of the result are undefined. The
4377condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4378<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4379
4380<h5>Example:</h5>
4381<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4382 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4383 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4384
4385 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4386 &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]4387</pre>
4388</div>
4389
4390<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4391<div class="doc_subsubsection">
4392 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4393</div>
4394
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4395<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4397<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4398
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4399<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4400<h5>Overview:</h5>
4401<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4402the SSA graph representing the function.</p>
4403<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4404
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4405<p>The type of the incoming values is specified with the first type
4406field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4407as arguments, with one pair for each predecessor basic block of the
4408current block. Only values of <a href="#t_firstclass">first class</a>
4409type may be used as the value arguments to the PHI node. Only labels
4410may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4412<p>There must be no non-phi instructions between the start of a basic
4413block and the PHI instructions: i.e. PHI instructions must be first in
4414a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4416<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4417
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4418<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4419specified by the pair corresponding to the predecessor basic block that executed
4420just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4422<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4423<pre>
4424Loop: ; Infinite loop that counts from 0 on up...
4425 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4426 %nextindvar = add i32 %indvar, 1
4427 br label %Loop
4428</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4429</div>
4430
4431<!-- _______________________________________________________________________ -->
4432<div class="doc_subsubsection">
4433 <a name="i_select">'<tt>select</tt>' Instruction</a>
4434</div>
4435
4436<div class="doc_text">
4437
4438<h5>Syntax:</h5>
4439
4440<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4441 &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>
4442
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4443 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4444</pre>
4445
4446<h5>Overview:</h5>
4447
4448<p>
4449The '<tt>select</tt>' instruction is used to choose one value based on a
4450condition, without branching.
4451</p>
4452
4453
4454<h5>Arguments:</h5>
4455
4456<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4457The '<tt>select</tt>' instruction requires an 'i1' value or
4458a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4459condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4460type. If the val1/val2 are vectors and
4461the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4462individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4463</p>
4464
4465<h5>Semantics:</h5>
4466
4467<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4468If 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]4469value argument; otherwise, it returns the second value argument.
4470</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4471<p>
4472If the condition is a vector of i1, then the value arguments must
4473be vectors of the same size, and the selection is done element
4474by element.
4475</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476
4477<h5>Example:</h5>
4478
4479<pre>
4480 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4481</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4482
4483<p>Note that the code generator does not yet support conditions
4484 with vector type.</p>
4485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486</div>
4487
4488
4489<!-- _______________________________________________________________________ -->
4490<div class="doc_subsubsection">
4491 <a name="i_call">'<tt>call</tt>' Instruction</a>
4492</div>
4493
4494<div class="doc_text">
4495
4496<h5>Syntax:</h5>
4497<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4498 &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]4499</pre>
4500
4501<h5>Overview:</h5>
4502
4503<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4504
4505<h5>Arguments:</h5>
4506
4507<p>This instruction requires several arguments:</p>
4508
4509<ol>
4510 <li>
4511 <p>The optional "tail" marker indicates whether the callee function accesses
4512 any allocas or varargs in the caller. If the "tail" marker is present, the
4513 function call is eligible for tail call optimization. Note that calls may
4514 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4515 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516 </li>
4517 <li>
4518 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4519 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4520 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4521 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4522
4523 <li>
4524 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4525 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4526 and '<tt>inreg</tt>' attributes are valid here.</p>
4527 </li>
4528
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4529 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4530 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4531 the type of the return value. Functions that return no value are marked
4532 <tt><a href="#t_void">void</a></tt>.</p>
4533 </li>
4534 <li>
4535 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4536 value being invoked. The argument types must match the types implied by
4537 this signature. This type can be omitted if the function is not varargs
4538 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4539 </li>
4540 <li>
4541 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4542 be invoked. In most cases, this is a direct function invocation, but
4543 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4544 to function value.</p>
4545 </li>
4546 <li>
4547 <p>'<tt>function args</tt>': argument list whose types match the
4548 function signature argument types. All arguments must be of
4549 <a href="#t_firstclass">first class</a> type. If the function signature
4550 indicates the function accepts a variable number of arguments, the extra
4551 arguments can be specified.</p>
4552 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4553 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4554 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4555 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4556 '<tt>readnone</tt>' attributes are valid here.</p>
4557 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4558</ol>
4559
4560<h5>Semantics:</h5>
4561
4562<p>The '<tt>call</tt>' instruction is used to cause control flow to
4563transfer to a specified function, with its incoming arguments bound to
4564the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4565instruction in the called function, control flow continues with the
4566instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4567function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4568
4569<h5>Example:</h5>
4570
4571<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4572 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4573 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4574 %X = tail call i32 @foo() <i>; yields i32</i>
4575 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4576 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4577
4578 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4579 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4580 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4581 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4582 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4583 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4584</pre>
4585
4586</div>
4587
4588<!-- _______________________________________________________________________ -->
4589<div class="doc_subsubsection">
4590 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4591</div>
4592
4593<div class="doc_text">
4594
4595<h5>Syntax:</h5>
4596
4597<pre>
4598 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4599</pre>
4600
4601<h5>Overview:</h5>
4602
4603<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4604the "variable argument" area of a function call. It is used to implement the
4605<tt>va_arg</tt> macro in C.</p>
4606
4607<h5>Arguments:</h5>
4608
4609<p>This instruction takes a <tt>va_list*</tt> value and the type of
4610the argument. It returns a value of the specified argument type and
4611increments the <tt>va_list</tt> to point to the next argument. The
4612actual type of <tt>va_list</tt> is target specific.</p>
4613
4614<h5>Semantics:</h5>
4615
4616<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4617type from the specified <tt>va_list</tt> and causes the
4618<tt>va_list</tt> to point to the next argument. For more information,
4619see the variable argument handling <a href="#int_varargs">Intrinsic
4620Functions</a>.</p>
4621
4622<p>It is legal for this instruction to be called in a function which does not
4623take a variable number of arguments, for example, the <tt>vfprintf</tt>
4624function.</p>
4625
4626<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4627href="#intrinsics">intrinsic function</a> because it takes a type as an
4628argument.</p>
4629
4630<h5>Example:</h5>
4631
4632<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4633
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4634<p>Note that the code generator does not yet fully support va_arg
4635 on many targets. Also, it does not currently support va_arg with
4636 aggregate types on any target.</p>
4637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4638</div>
4639
4640<!-- *********************************************************************** -->
4641<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4642<!-- *********************************************************************** -->
4643
4644<div class="doc_text">
4645
4646<p>LLVM supports the notion of an "intrinsic function". These functions have
4647well known names and semantics and are required to follow certain restrictions.
4648Overall, these intrinsics represent an extension mechanism for the LLVM
4649language that does not require changing all of the transformations in LLVM when
4650adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4651
4652<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4653prefix is reserved in LLVM for intrinsic names; thus, function names may not
4654begin with this prefix. Intrinsic functions must always be external functions:
4655you cannot define the body of intrinsic functions. Intrinsic functions may
4656only be used in call or invoke instructions: it is illegal to take the address
4657of an intrinsic function. Additionally, because intrinsic functions are part
4658of the LLVM language, it is required if any are added that they be documented
4659here.</p>
4660
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4661<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4662a family of functions that perform the same operation but on different data
4663types. Because LLVM can represent over 8 million different integer types,
4664overloading is used commonly to allow an intrinsic function to operate on any
4665integer type. One or more of the argument types or the result type can be
4666overloaded to accept any integer type. Argument types may also be defined as
4667exactly matching a previous argument's type or the result type. This allows an
4668intrinsic function which accepts multiple arguments, but needs all of them to
4669be of the same type, to only be overloaded with respect to a single argument or
4670the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4671
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4672<p>Overloaded intrinsics will have the names of its overloaded argument types
4673encoded into its function name, each preceded by a period. Only those types
4674which are overloaded result in a name suffix. Arguments whose type is matched
4675against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4676take an integer of any width and returns an integer of exactly the same integer
4677width. This leads to a family of functions such as
4678<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4679Only one type, the return type, is overloaded, and only one type suffix is
4680required. Because the argument's type is matched against the return type, it
4681does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4682
4683<p>To learn how to add an intrinsic function, please see the
4684<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4685</p>
4686
4687</div>
4688
4689<!-- ======================================================================= -->
4690<div class="doc_subsection">
4691 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4692</div>
4693
4694<div class="doc_text">
4695
4696<p>Variable argument support is defined in LLVM with the <a
4697 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4698intrinsic functions. These functions are related to the similarly
4699named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4700
4701<p>All of these functions operate on arguments that use a
4702target-specific value type "<tt>va_list</tt>". The LLVM assembly
4703language reference manual does not define what this type is, so all
4704transformations should be prepared to handle these functions regardless of
4705the type used.</p>
4706
4707<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4708instruction and the variable argument handling intrinsic functions are
4709used.</p>
4710
4711<div class="doc_code">
4712<pre>
4713define i32 @test(i32 %X, ...) {
4714 ; Initialize variable argument processing
4715 %ap = alloca i8*
4716 %ap2 = bitcast i8** %ap to i8*
4717 call void @llvm.va_start(i8* %ap2)
4718
4719 ; Read a single integer argument
4720 %tmp = va_arg i8** %ap, i32
4721
4722 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4723 %aq = alloca i8*
4724 %aq2 = bitcast i8** %aq to i8*
4725 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4726 call void @llvm.va_end(i8* %aq2)
4727
4728 ; Stop processing of arguments.
4729 call void @llvm.va_end(i8* %ap2)
4730 ret i32 %tmp
4731}
4732
4733declare void @llvm.va_start(i8*)
4734declare void @llvm.va_copy(i8*, i8*)
4735declare void @llvm.va_end(i8*)
4736</pre>
4737</div>
4738
4739</div>
4740
4741<!-- _______________________________________________________________________ -->
4742<div class="doc_subsubsection">
4743 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4744</div>
4745
4746
4747<div class="doc_text">
4748<h5>Syntax:</h5>
4749<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4750<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4751<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4752<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4753href="#i_va_arg">va_arg</a></tt>.</p>
4754
4755<h5>Arguments:</h5>
4756
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4757<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]4758
4759<h5>Semantics:</h5>
4760
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4761<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]4762macro available in C. In a target-dependent way, it initializes the
4763<tt>va_list</tt> element to which the argument points, so that the next call to
4764<tt>va_arg</tt> will produce the first variable argument passed to the function.
4765Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4766last argument of the function as the compiler can figure that out.</p>
4767
4768</div>
4769
4770<!-- _______________________________________________________________________ -->
4771<div class="doc_subsubsection">
4772 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4773</div>
4774
4775<div class="doc_text">
4776<h5>Syntax:</h5>
4777<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4778<h5>Overview:</h5>
4779
4780<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4781which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4782or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4783
4784<h5>Arguments:</h5>
4785
4786<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4787
4788<h5>Semantics:</h5>
4789
4790<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4791macro available in C. In a target-dependent way, it destroys the
4792<tt>va_list</tt> element to which the argument points. Calls to <a
4793href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4794<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4795<tt>llvm.va_end</tt>.</p>
4796
4797</div>
4798
4799<!-- _______________________________________________________________________ -->
4800<div class="doc_subsubsection">
4801 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4802</div>
4803
4804<div class="doc_text">
4805
4806<h5>Syntax:</h5>
4807
4808<pre>
4809 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4810</pre>
4811
4812<h5>Overview:</h5>
4813
4814<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4815from the source argument list to the destination argument list.</p>
4816
4817<h5>Arguments:</h5>
4818
4819<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4820The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4821
4822
4823<h5>Semantics:</h5>
4824
4825<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4826macro available in C. In a target-dependent way, it copies the source
4827<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4828intrinsic is necessary because the <tt><a href="#int_va_start">
4829llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4830example, memory allocation.</p>
4831
4832</div>
4833
4834<!-- ======================================================================= -->
4835<div class="doc_subsection">
4836 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4837</div>
4838
4839<div class="doc_text">
4840
4841<p>
4842LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4843Collection</a> (GC) requires the implementation and generation of these
4844intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4845These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4846stack</a>, as well as garbage collector implementations that require <a
4847href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4848Front-ends for type-safe garbage collected languages should generate these
4849intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4850href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4851</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4852
4853<p>The garbage collection intrinsics only operate on objects in the generic
4854 address space (address space zero).</p>
4855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4856</div>
4857
4858<!-- _______________________________________________________________________ -->
4859<div class="doc_subsubsection">
4860 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4861</div>
4862
4863<div class="doc_text">
4864
4865<h5>Syntax:</h5>
4866
4867<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4868 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4869</pre>
4870
4871<h5>Overview:</h5>
4872
4873<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4874the code generator, and allows some metadata to be associated with it.</p>
4875
4876<h5>Arguments:</h5>
4877
4878<p>The first argument specifies the address of a stack object that contains the
4879root pointer. The second pointer (which must be either a constant or a global
4880value address) contains the meta-data to be associated with the root.</p>
4881
4882<h5>Semantics:</h5>
4883
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4884<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]4885location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4886the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4887intrinsic may only be used in a function which <a href="#gc">specifies a GC
4888algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4889
4890</div>
4891
4892
4893<!-- _______________________________________________________________________ -->
4894<div class="doc_subsubsection">
4895 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4896</div>
4897
4898<div class="doc_text">
4899
4900<h5>Syntax:</h5>
4901
4902<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4903 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4904</pre>
4905
4906<h5>Overview:</h5>
4907
4908<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4909locations, allowing garbage collector implementations that require read
4910barriers.</p>
4911
4912<h5>Arguments:</h5>
4913
4914<p>The second argument is the address to read from, which should be an address
4915allocated from the garbage collector. The first object is a pointer to the
4916start of the referenced object, if needed by the language runtime (otherwise
4917null).</p>
4918
4919<h5>Semantics:</h5>
4920
4921<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4922instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4923garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4924may only be used in a function which <a href="#gc">specifies a GC
4925algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4926
4927</div>
4928
4929
4930<!-- _______________________________________________________________________ -->
4931<div class="doc_subsubsection">
4932 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4933</div>
4934
4935<div class="doc_text">
4936
4937<h5>Syntax:</h5>
4938
4939<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4940 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4941</pre>
4942
4943<h5>Overview:</h5>
4944
4945<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4946locations, allowing garbage collector implementations that require write
4947barriers (such as generational or reference counting collectors).</p>
4948
4949<h5>Arguments:</h5>
4950
4951<p>The first argument is the reference to store, the second is the start of the
4952object to store it to, and the third is the address of the field of Obj to
4953store to. If the runtime does not require a pointer to the object, Obj may be
4954null.</p>
4955
4956<h5>Semantics:</h5>
4957
4958<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4959instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4960garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4961may only be used in a function which <a href="#gc">specifies a GC
4962algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4963
4964</div>
4965
4966
4967
4968<!-- ======================================================================= -->
4969<div class="doc_subsection">
4970 <a name="int_codegen">Code Generator Intrinsics</a>
4971</div>
4972
4973<div class="doc_text">
4974<p>
4975These intrinsics are provided by LLVM to expose special features that may only
4976be implemented with code generator support.
4977</p>
4978
4979</div>
4980
4981<!-- _______________________________________________________________________ -->
4982<div class="doc_subsubsection">
4983 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4984</div>
4985
4986<div class="doc_text">
4987
4988<h5>Syntax:</h5>
4989<pre>
4990 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4991</pre>
4992
4993<h5>Overview:</h5>
4994
4995<p>
4996The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4997target-specific value indicating the return address of the current function
4998or one of its callers.
4999</p>
5000
5001<h5>Arguments:</h5>
5002
5003<p>
5004The argument to this intrinsic indicates which function to return the address
5005for. Zero indicates the calling function, one indicates its caller, etc. The
5006argument is <b>required</b> to be a constant integer value.
5007</p>
5008
5009<h5>Semantics:</h5>
5010
5011<p>
5012The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5013the return address of the specified call frame, or zero if it cannot be
5014identified. The value returned by this intrinsic is likely to be incorrect or 0
5015for arguments other than zero, so it should only be used for debugging purposes.
5016</p>
5017
5018<p>
5019Note that calling this intrinsic does not prevent function inlining or other
5020aggressive transformations, so the value returned may not be that of the obvious
5021source-language caller.
5022</p>
5023</div>
5024
5025
5026<!-- _______________________________________________________________________ -->
5027<div class="doc_subsubsection">
5028 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5029</div>
5030
5031<div class="doc_text">
5032
5033<h5>Syntax:</h5>
5034<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5035 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5036</pre>
5037
5038<h5>Overview:</h5>
5039
5040<p>
5041The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5042target-specific frame pointer value for the specified stack frame.
5043</p>
5044
5045<h5>Arguments:</h5>
5046
5047<p>
5048The argument to this intrinsic indicates which function to return the frame
5049pointer for. Zero indicates the calling function, one indicates its caller,
5050etc. The argument is <b>required</b> to be a constant integer value.
5051</p>
5052
5053<h5>Semantics:</h5>
5054
5055<p>
5056The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5057the frame address of the specified call frame, or zero if it cannot be
5058identified. The value returned by this intrinsic is likely to be incorrect or 0
5059for arguments other than zero, so it should only be used for debugging purposes.
5060</p>
5061
5062<p>
5063Note that calling this intrinsic does not prevent function inlining or other
5064aggressive transformations, so the value returned may not be that of the obvious
5065source-language caller.
5066</p>
5067</div>
5068
5069<!-- _______________________________________________________________________ -->
5070<div class="doc_subsubsection">
5071 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5072</div>
5073
5074<div class="doc_text">
5075
5076<h5>Syntax:</h5>
5077<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5078 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079</pre>
5080
5081<h5>Overview:</h5>
5082
5083<p>
5084The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5085the function stack, for use with <a href="#int_stackrestore">
5086<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5087features like scoped automatic variable sized arrays in C99.
5088</p>
5089
5090<h5>Semantics:</h5>
5091
5092<p>
5093This intrinsic returns a opaque pointer value that can be passed to <a
5094href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5095<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5096<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5097state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5098practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5099that were allocated after the <tt>llvm.stacksave</tt> was executed.
5100</p>
5101
5102</div>
5103
5104<!-- _______________________________________________________________________ -->
5105<div class="doc_subsubsection">
5106 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5107</div>
5108
5109<div class="doc_text">
5110
5111<h5>Syntax:</h5>
5112<pre>
5113 declare void @llvm.stackrestore(i8 * %ptr)
5114</pre>
5115
5116<h5>Overview:</h5>
5117
5118<p>
5119The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5120the function stack to the state it was in when the corresponding <a
5121href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5122useful for implementing language features like scoped automatic variable sized
5123arrays in C99.
5124</p>
5125
5126<h5>Semantics:</h5>
5127
5128<p>
5129See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5130</p>
5131
5132</div>
5133
5134
5135<!-- _______________________________________________________________________ -->
5136<div class="doc_subsubsection">
5137 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5138</div>
5139
5140<div class="doc_text">
5141
5142<h5>Syntax:</h5>
5143<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5144 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]5145</pre>
5146
5147<h5>Overview:</h5>
5148
5149
5150<p>
5151The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5152a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5153no
5154effect on the behavior of the program but can change its performance
5155characteristics.
5156</p>
5157
5158<h5>Arguments:</h5>
5159
5160<p>
5161<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5162determining if the fetch should be for a read (0) or write (1), and
5163<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5164locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5165<tt>locality</tt> arguments must be constant integers.
5166</p>
5167
5168<h5>Semantics:</h5>
5169
5170<p>
5171This intrinsic does not modify the behavior of the program. In particular,
5172prefetches cannot trap and do not produce a value. On targets that support this
5173intrinsic, the prefetch can provide hints to the processor cache for better
5174performance.
5175</p>
5176
5177</div>
5178
5179<!-- _______________________________________________________________________ -->
5180<div class="doc_subsubsection">
5181 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5182</div>
5183
5184<div class="doc_text">
5185
5186<h5>Syntax:</h5>
5187<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5188 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5189</pre>
5190
5191<h5>Overview:</h5>
5192
5193
5194<p>
5195The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5196(PC) in a region of
5197code to simulators and other tools. The method is target specific, but it is
5198expected that the marker will use exported symbols to transmit the PC of the
5199marker.
5200The marker makes no guarantees that it will remain with any specific instruction
5201after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202optimizations. The intended use is to be inserted after optimizations to allow
5203correlations of simulation runs.
5204</p>
5205
5206<h5>Arguments:</h5>
5207
5208<p>
5209<tt>id</tt> is a numerical id identifying the marker.
5210</p>
5211
5212<h5>Semantics:</h5>
5213
5214<p>
5215This intrinsic does not modify the behavior of the program. Backends that do not
5216support this intrinisic may ignore it.
5217</p>
5218
5219</div>
5220
5221<!-- _______________________________________________________________________ -->
5222<div class="doc_subsubsection">
5223 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5224</div>
5225
5226<div class="doc_text">
5227
5228<h5>Syntax:</h5>
5229<pre>
5230 declare i64 @llvm.readcyclecounter( )
5231</pre>
5232
5233<h5>Overview:</h5>
5234
5235
5236<p>
5237The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5238counter register (or similar low latency, high accuracy clocks) on those targets
5239that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5240As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5241should only be used for small timings.
5242</p>
5243
5244<h5>Semantics:</h5>
5245
5246<p>
5247When directly supported, reading the cycle counter should not modify any memory.
5248Implementations are allowed to either return a application specific value or a
5249system wide value. On backends without support, this is lowered to a constant 0.
5250</p>
5251
5252</div>
5253
5254<!-- ======================================================================= -->
5255<div class="doc_subsection">
5256 <a name="int_libc">Standard C Library Intrinsics</a>
5257</div>
5258
5259<div class="doc_text">
5260<p>
5261LLVM provides intrinsics for a few important standard C library functions.
5262These intrinsics allow source-language front-ends to pass information about the
5263alignment of the pointer arguments to the code generator, providing opportunity
5264for more efficient code generation.
5265</p>
5266
5267</div>
5268
5269<!-- _______________________________________________________________________ -->
5270<div class="doc_subsubsection">
5271 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5272</div>
5273
5274<div class="doc_text">
5275
5276<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5277<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5278width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5280 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5281 i8 &lt;len&gt;, i32 &lt;align&gt;)
5282 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5283 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5284 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5285 i32 &lt;len&gt;, i32 &lt;align&gt;)
5286 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5287 i64 &lt;len&gt;, i32 &lt;align&gt;)
5288</pre>
5289
5290<h5>Overview:</h5>
5291
5292<p>
5293The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5294location to the destination location.
5295</p>
5296
5297<p>
5298Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5299intrinsics do not return a value, and takes an extra alignment argument.
5300</p>
5301
5302<h5>Arguments:</h5>
5303
5304<p>
5305The first argument is a pointer to the destination, the second is a pointer to
5306the source. The third argument is an integer argument
5307specifying the number of bytes to copy, and the fourth argument is the alignment
5308of the source and destination locations.
5309</p>
5310
5311<p>
5312If the call to this intrinisic has an alignment value that is not 0 or 1, then
5313the caller guarantees that both the source and destination pointers are aligned
5314to that boundary.
5315</p>
5316
5317<h5>Semantics:</h5>
5318
5319<p>
5320The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5321location to the destination location, which are not allowed to overlap. It
5322copies "len" bytes of memory over. If the argument is known to be aligned to
5323some boundary, this can be specified as the fourth argument, otherwise it should
5324be set to 0 or 1.
5325</p>
5326</div>
5327
5328
5329<!-- _______________________________________________________________________ -->
5330<div class="doc_subsubsection">
5331 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5332</div>
5333
5334<div class="doc_text">
5335
5336<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5337<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5338width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5340 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5341 i8 &lt;len&gt;, i32 &lt;align&gt;)
5342 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5343 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5344 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5345 i32 &lt;len&gt;, i32 &lt;align&gt;)
5346 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5347 i64 &lt;len&gt;, i32 &lt;align&gt;)
5348</pre>
5349
5350<h5>Overview:</h5>
5351
5352<p>
5353The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5354location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5355'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5356</p>
5357
5358<p>
5359Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5360intrinsics do not return a value, and takes an extra alignment argument.
5361</p>
5362
5363<h5>Arguments:</h5>
5364
5365<p>
5366The first argument is a pointer to the destination, the second is a pointer to
5367the source. The third argument is an integer argument
5368specifying the number of bytes to copy, and the fourth argument is the alignment
5369of the source and destination locations.
5370</p>
5371
5372<p>
5373If the call to this intrinisic has an alignment value that is not 0 or 1, then
5374the caller guarantees that the source and destination pointers are aligned to
5375that boundary.
5376</p>
5377
5378<h5>Semantics:</h5>
5379
5380<p>
5381The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5382location to the destination location, which may overlap. It
5383copies "len" bytes of memory over. If the argument is known to be aligned to
5384some boundary, this can be specified as the fourth argument, otherwise it should
5385be set to 0 or 1.
5386</p>
5387</div>
5388
5389
5390<!-- _______________________________________________________________________ -->
5391<div class="doc_subsubsection">
5392 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5393</div>
5394
5395<div class="doc_text">
5396
5397<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5398<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5399width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5401 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5402 i8 &lt;len&gt;, i32 &lt;align&gt;)
5403 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5404 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5405 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5406 i32 &lt;len&gt;, i32 &lt;align&gt;)
5407 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5408 i64 &lt;len&gt;, i32 &lt;align&gt;)
5409</pre>
5410
5411<h5>Overview:</h5>
5412
5413<p>
5414The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5415byte value.
5416</p>
5417
5418<p>
5419Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5420does not return a value, and takes an extra alignment argument.
5421</p>
5422
5423<h5>Arguments:</h5>
5424
5425<p>
5426The first argument is a pointer to the destination to fill, the second is the
5427byte value to fill it with, the third argument is an integer
5428argument specifying the number of bytes to fill, and the fourth argument is the
5429known alignment of destination location.
5430</p>
5431
5432<p>
5433If the call to this intrinisic has an alignment value that is not 0 or 1, then
5434the caller guarantees that the destination pointer is aligned to that boundary.
5435</p>
5436
5437<h5>Semantics:</h5>
5438
5439<p>
5440The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5441the
5442destination location. If the argument is known to be aligned to some boundary,
5443this can be specified as the fourth argument, otherwise it should be set to 0 or
54441.
5445</p>
5446</div>
5447
5448
5449<!-- _______________________________________________________________________ -->
5450<div class="doc_subsubsection">
5451 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5452</div>
5453
5454<div class="doc_text">
5455
5456<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5457<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]5458floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5459types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5460<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5461 declare float @llvm.sqrt.f32(float %Val)
5462 declare double @llvm.sqrt.f64(double %Val)
5463 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5464 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5465 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5466</pre>
5467
5468<h5>Overview:</h5>
5469
5470<p>
5471The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5472returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5473<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5474negative numbers other than -0.0 (which allows for better optimization, because
5475there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5476defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5477</p>
5478
5479<h5>Arguments:</h5>
5480
5481<p>
5482The argument and return value are floating point numbers of the same type.
5483</p>
5484
5485<h5>Semantics:</h5>
5486
5487<p>
5488This function returns the sqrt of the specified operand if it is a nonnegative
5489floating point number.
5490</p>
5491</div>
5492
5493<!-- _______________________________________________________________________ -->
5494<div class="doc_subsubsection">
5495 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5496</div>
5497
5498<div class="doc_text">
5499
5500<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5501<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]5502floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5503types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5504<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5505 declare float @llvm.powi.f32(float %Val, i32 %power)
5506 declare double @llvm.powi.f64(double %Val, i32 %power)
5507 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5508 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5509 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5510</pre>
5511
5512<h5>Overview:</h5>
5513
5514<p>
5515The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5516specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5517multiplications is not defined. When a vector of floating point type is
5518used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519</p>
5520
5521<h5>Arguments:</h5>
5522
5523<p>
5524The second argument is an integer power, and the first is a value to raise to
5525that power.
5526</p>
5527
5528<h5>Semantics:</h5>
5529
5530<p>
5531This function returns the first value raised to the second power with an
5532unspecified sequence of rounding operations.</p>
5533</div>
5534
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5535<!-- _______________________________________________________________________ -->
5536<div class="doc_subsubsection">
5537 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5538</div>
5539
5540<div class="doc_text">
5541
5542<h5>Syntax:</h5>
5543<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5544floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5545types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5546<pre>
5547 declare float @llvm.sin.f32(float %Val)
5548 declare double @llvm.sin.f64(double %Val)
5549 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5550 declare fp128 @llvm.sin.f128(fp128 %Val)
5551 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5552</pre>
5553
5554<h5>Overview:</h5>
5555
5556<p>
5557The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5558</p>
5559
5560<h5>Arguments:</h5>
5561
5562<p>
5563The argument and return value are floating point numbers of the same type.
5564</p>
5565
5566<h5>Semantics:</h5>
5567
5568<p>
5569This function returns the sine of the specified operand, returning the
5570same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5571conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5572</div>
5573
5574<!-- _______________________________________________________________________ -->
5575<div class="doc_subsubsection">
5576 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5577</div>
5578
5579<div class="doc_text">
5580
5581<h5>Syntax:</h5>
5582<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5583floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5584types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5585<pre>
5586 declare float @llvm.cos.f32(float %Val)
5587 declare double @llvm.cos.f64(double %Val)
5588 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5589 declare fp128 @llvm.cos.f128(fp128 %Val)
5590 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5591</pre>
5592
5593<h5>Overview:</h5>
5594
5595<p>
5596The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5597</p>
5598
5599<h5>Arguments:</h5>
5600
5601<p>
5602The argument and return value are floating point numbers of the same type.
5603</p>
5604
5605<h5>Semantics:</h5>
5606
5607<p>
5608This function returns the cosine of the specified operand, returning the
5609same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5610conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5611</div>
5612
5613<!-- _______________________________________________________________________ -->
5614<div class="doc_subsubsection">
5615 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5616</div>
5617
5618<div class="doc_text">
5619
5620<h5>Syntax:</h5>
5621<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5622floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5623types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5624<pre>
5625 declare float @llvm.pow.f32(float %Val, float %Power)
5626 declare double @llvm.pow.f64(double %Val, double %Power)
5627 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5628 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5629 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5630</pre>
5631
5632<h5>Overview:</h5>
5633
5634<p>
5635The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5636specified (positive or negative) power.
5637</p>
5638
5639<h5>Arguments:</h5>
5640
5641<p>
5642The second argument is a floating point power, and the first is a value to
5643raise to that power.
5644</p>
5645
5646<h5>Semantics:</h5>
5647
5648<p>
5649This function returns the first value raised to the second power,
5650returning the
5651same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5652conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5653</div>
5654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5655
5656<!-- ======================================================================= -->
5657<div class="doc_subsection">
5658 <a name="int_manip">Bit Manipulation Intrinsics</a>
5659</div>
5660
5661<div class="doc_text">
5662<p>
5663LLVM provides intrinsics for a few important bit manipulation operations.
5664These allow efficient code generation for some algorithms.
5665</p>
5666
5667</div>
5668
5669<!-- _______________________________________________________________________ -->
5670<div class="doc_subsubsection">
5671 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5672</div>
5673
5674<div class="doc_text">
5675
5676<h5>Syntax:</h5>
5677<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5678type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5679<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5680 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5681 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5682 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5683</pre>
5684
5685<h5>Overview:</h5>
5686
5687<p>
5688The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5689values with an even number of bytes (positive multiple of 16 bits). These are
5690useful for performing operations on data that is not in the target's native
5691byte order.
5692</p>
5693
5694<h5>Semantics:</h5>
5695
5696<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5697The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5698and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5699intrinsic returns an i32 value that has the four bytes of the input i32
5700swapped, 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]5701i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5702<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5703additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5704</p>
5705
5706</div>
5707
5708<!-- _______________________________________________________________________ -->
5709<div class="doc_subsubsection">
5710 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5711</div>
5712
5713<div class="doc_text">
5714
5715<h5>Syntax:</h5>
5716<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]5717width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5718<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5719 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5720 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5721 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5722 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5723 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5724</pre>
5725
5726<h5>Overview:</h5>
5727
5728<p>
5729The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5730value.
5731</p>
5732
5733<h5>Arguments:</h5>
5734
5735<p>
5736The only argument is the value to be counted. The argument may be of any
5737integer type. The return type must match the argument type.
5738</p>
5739
5740<h5>Semantics:</h5>
5741
5742<p>
5743The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5744</p>
5745</div>
5746
5747<!-- _______________________________________________________________________ -->
5748<div class="doc_subsubsection">
5749 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5750</div>
5751
5752<div class="doc_text">
5753
5754<h5>Syntax:</h5>
5755<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]5756integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5757<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5758 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5759 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5760 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5761 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5762 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5763</pre>
5764
5765<h5>Overview:</h5>
5766
5767<p>
5768The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5769leading zeros in a variable.
5770</p>
5771
5772<h5>Arguments:</h5>
5773
5774<p>
5775The only argument is the value to be counted. The argument may be of any
5776integer type. The return type must match the argument type.
5777</p>
5778
5779<h5>Semantics:</h5>
5780
5781<p>
5782The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5783in a variable. If the src == 0 then the result is the size in bits of the type
5784of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5785</p>
5786</div>
5787
5788
5789
5790<!-- _______________________________________________________________________ -->
5791<div class="doc_subsubsection">
5792 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5793</div>
5794
5795<div class="doc_text">
5796
5797<h5>Syntax:</h5>
5798<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]5799integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5800<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5801 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5802 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5803 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5804 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5805 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5806</pre>
5807
5808<h5>Overview:</h5>
5809
5810<p>
5811The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5812trailing zeros.
5813</p>
5814
5815<h5>Arguments:</h5>
5816
5817<p>
5818The only argument is the value to be counted. The argument may be of any
5819integer type. The return type must match the argument type.
5820</p>
5821
5822<h5>Semantics:</h5>
5823
5824<p>
5825The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5826in a variable. If the src == 0 then the result is the size in bits of the type
5827of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5828</p>
5829</div>
5830
5831<!-- _______________________________________________________________________ -->
5832<div class="doc_subsubsection">
5833 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5834</div>
5835
5836<div class="doc_text">
5837
5838<h5>Syntax:</h5>
5839<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5840on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5841<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5842 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5843 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5844</pre>
5845
5846<h5>Overview:</h5>
5847<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5848range of bits from an integer value and returns them in the same bit width as
5849the original value.</p>
5850
5851<h5>Arguments:</h5>
5852<p>The first argument, <tt>%val</tt> and the result may be integer types of
5853any bit width but they must have the same bit width. The second and third
5854arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5855
5856<h5>Semantics:</h5>
5857<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5858of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5859<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5860operates in forward mode.</p>
5861<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5862right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5863only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5864<ol>
5865 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5866 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5867 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5868 to determine the number of bits to retain.</li>
5869 <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]5870 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5871</ol>
5872<p>In reverse mode, a similar computation is made except that the bits are
5873returned in the reverse order. So, for example, if <tt>X</tt> has the value
5874<tt>i16 0x0ACF (101011001111)</tt> and we apply
5875<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5876<tt>i16 0x0026 (000000100110)</tt>.</p>
5877</div>
5878
5879<div class="doc_subsubsection">
5880 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5881</div>
5882
5883<div class="doc_text">
5884
5885<h5>Syntax:</h5>
5886<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5887on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5888<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5889 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5890 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]5891</pre>
5892
5893<h5>Overview:</h5>
5894<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5895of bits in an integer value with another integer value. It returns the integer
5896with the replaced bits.</p>
5897
5898<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5899<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5900any 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]5901whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5902integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5903type since they specify only a bit index.</p>
5904
5905<h5>Semantics:</h5>
5906<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5907of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5908<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5909operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5910
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5911<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5912truncating it down to the size of the replacement area or zero extending it
5913up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5915<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5916are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5917in <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]5918to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5919
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5920<p>In reverse mode, a similar computation is made except that the bits are
5921reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5922<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]5923
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5924<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5925
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5926<pre>
5927 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5928 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5929 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5930 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5931 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5932</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5933
5934</div>
5935
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5936<!-- ======================================================================= -->
5937<div class="doc_subsection">
5938 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5939</div>
5940
5941<div class="doc_text">
5942<p>
5943LLVM provides intrinsics for some arithmetic with overflow operations.
5944</p>
5945
5946</div>
5947
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5948<!-- _______________________________________________________________________ -->
5949<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5950 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5951</div>
5952
5953<div class="doc_text">
5954
5955<h5>Syntax:</h5>
5956
5957<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]5958on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5959
5960<pre>
5961 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5962 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5963 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5964</pre>
5965
5966<h5>Overview:</h5>
5967
5968<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5969a signed addition of the two arguments, and indicate whether an overflow
5970occurred during the signed summation.</p>
5971
5972<h5>Arguments:</h5>
5973
5974<p>The arguments (%a and %b) and the first element of the result structure may
5975be of integer types of any bit width, but they must have the same bit width. The
5976second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5977and <tt>%b</tt> are the two values that will undergo signed addition.</p>
5978
5979<h5>Semantics:</h5>
5980
5981<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5982a signed addition of the two variables. They return a structure &mdash; the
5983first element of which is the signed summation, and the second element of which
5984is a bit specifying if the signed summation resulted in an overflow.</p>
5985
5986<h5>Examples:</h5>
5987<pre>
5988 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5989 %sum = extractvalue {i32, i1} %res, 0
5990 %obit = extractvalue {i32, i1} %res, 1
5991 br i1 %obit, label %overflow, label %normal
5992</pre>
5993
5994</div>
5995
5996<!-- _______________________________________________________________________ -->
5997<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5998 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5999</div>
6000
6001<div class="doc_text">
6002
6003<h5>Syntax:</h5>
6004
6005<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]6006on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6007
6008<pre>
6009 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6010 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6011 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6012</pre>
6013
6014<h5>Overview:</h5>
6015
6016<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6017an unsigned addition of the two arguments, and indicate whether a carry occurred
6018during the unsigned summation.</p>
6019
6020<h5>Arguments:</h5>
6021
6022<p>The arguments (%a and %b) and the first element of the result structure may
6023be of integer types of any bit width, but they must have the same bit width. The
6024second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6025and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6026
6027<h5>Semantics:</h5>
6028
6029<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6030an unsigned addition of the two arguments. They return a structure &mdash; the
6031first element of which is the sum, and the second element of which is a bit
6032specifying if the unsigned summation resulted in a carry.</p>
6033
6034<h5>Examples:</h5>
6035<pre>
6036 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6037 %sum = extractvalue {i32, i1} %res, 0
6038 %obit = extractvalue {i32, i1} %res, 1
6039 br i1 %obit, label %carry, label %normal
6040</pre>
6041
6042</div>
6043
6044<!-- _______________________________________________________________________ -->
6045<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6046 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6047</div>
6048
6049<div class="doc_text">
6050
6051<h5>Syntax:</h5>
6052
6053<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]6054on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6055
6056<pre>
6057 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6058 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6059 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6060</pre>
6061
6062<h5>Overview:</h5>
6063
6064<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6065a signed subtraction of the two arguments, and indicate whether an overflow
6066occurred during the signed subtraction.</p>
6067
6068<h5>Arguments:</h5>
6069
6070<p>The arguments (%a and %b) and the first element of the result structure may
6071be of integer types of any bit width, but they must have the same bit width. The
6072second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6073and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6074
6075<h5>Semantics:</h5>
6076
6077<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6078a signed subtraction of the two arguments. They return a structure &mdash; the
6079first element of which is the subtraction, and the second element of which is a bit
6080specifying if the signed subtraction resulted in an overflow.</p>
6081
6082<h5>Examples:</h5>
6083<pre>
6084 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6085 %sum = extractvalue {i32, i1} %res, 0
6086 %obit = extractvalue {i32, i1} %res, 1
6087 br i1 %obit, label %overflow, label %normal
6088</pre>
6089
6090</div>
6091
6092<!-- _______________________________________________________________________ -->
6093<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6094 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6095</div>
6096
6097<div class="doc_text">
6098
6099<h5>Syntax:</h5>
6100
6101<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]6102on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6103
6104<pre>
6105 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6106 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6107 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6108</pre>
6109
6110<h5>Overview:</h5>
6111
6112<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6113an unsigned subtraction of the two arguments, and indicate whether an overflow
6114occurred during the unsigned subtraction.</p>
6115
6116<h5>Arguments:</h5>
6117
6118<p>The arguments (%a and %b) and the first element of the result structure may
6119be of integer types of any bit width, but they must have the same bit width. The
6120second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6121and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6122
6123<h5>Semantics:</h5>
6124
6125<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6126an unsigned subtraction of the two arguments. They return a structure &mdash; the
6127first element of which is the subtraction, and the second element of which is a bit
6128specifying if the unsigned subtraction resulted in an overflow.</p>
6129
6130<h5>Examples:</h5>
6131<pre>
6132 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6133 %sum = extractvalue {i32, i1} %res, 0
6134 %obit = extractvalue {i32, i1} %res, 1
6135 br i1 %obit, label %overflow, label %normal
6136</pre>
6137
6138</div>
6139
6140<!-- _______________________________________________________________________ -->
6141<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6142 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6143</div>
6144
6145<div class="doc_text">
6146
6147<h5>Syntax:</h5>
6148
6149<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]6150on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6151
6152<pre>
6153 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6154 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6155 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6156</pre>
6157
6158<h5>Overview:</h5>
6159
6160<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6161a signed multiplication of the two arguments, and indicate whether an overflow
6162occurred during the signed multiplication.</p>
6163
6164<h5>Arguments:</h5>
6165
6166<p>The arguments (%a and %b) and the first element of the result structure may
6167be of integer types of any bit width, but they must have the same bit width. The
6168second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6169and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6170
6171<h5>Semantics:</h5>
6172
6173<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6174a signed multiplication of the two arguments. They return a structure &mdash;
6175the first element of which is the multiplication, and the second element of
6176which is a bit specifying if the signed multiplication resulted in an
6177overflow.</p>
6178
6179<h5>Examples:</h5>
6180<pre>
6181 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6182 %sum = extractvalue {i32, i1} %res, 0
6183 %obit = extractvalue {i32, i1} %res, 1
6184 br i1 %obit, label %overflow, label %normal
6185</pre>
6186
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6187</div>
6188
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6189<!-- _______________________________________________________________________ -->
6190<div class="doc_subsubsection">
6191 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6192</div>
6193
6194<div class="doc_text">
6195
6196<h5>Syntax:</h5>
6197
6198<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6199on any integer bit width.</p>
6200
6201<pre>
6202 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6203 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6204 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6205</pre>
6206
6207<h5>Overview:</h5>
6208
6209<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6210actively being fixed, but it should not currently be used!</i></p>
6211
6212<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6213a unsigned multiplication of the two arguments, and indicate whether an overflow
6214occurred during the unsigned multiplication.</p>
6215
6216<h5>Arguments:</h5>
6217
6218<p>The arguments (%a and %b) and the first element of the result structure may
6219be of integer types of any bit width, but they must have the same bit width. The
6220second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6221and <tt>%b</tt> are the two values that will undergo unsigned
6222multiplication.</p>
6223
6224<h5>Semantics:</h5>
6225
6226<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6227an unsigned multiplication of the two arguments. They return a structure &mdash;
6228the first element of which is the multiplication, and the second element of
6229which is a bit specifying if the unsigned multiplication resulted in an
6230overflow.</p>
6231
6232<h5>Examples:</h5>
6233<pre>
6234 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6235 %sum = extractvalue {i32, i1} %res, 0
6236 %obit = extractvalue {i32, i1} %res, 1
6237 br i1 %obit, label %overflow, label %normal
6238</pre>
6239
6240</div>
6241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6242<!-- ======================================================================= -->
6243<div class="doc_subsection">
6244 <a name="int_debugger">Debugger Intrinsics</a>
6245</div>
6246
6247<div class="doc_text">
6248<p>
6249The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6250are described in the <a
6251href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6252Debugging</a> document.
6253</p>
6254</div>
6255
6256
6257<!-- ======================================================================= -->
6258<div class="doc_subsection">
6259 <a name="int_eh">Exception Handling Intrinsics</a>
6260</div>
6261
6262<div class="doc_text">
6263<p> The LLVM exception handling intrinsics (which all start with
6264<tt>llvm.eh.</tt> prefix), are described in the <a
6265href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6266Handling</a> document. </p>
6267</div>
6268
6269<!-- ======================================================================= -->
6270<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6271 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6272</div>
6273
6274<div class="doc_text">
6275<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6276 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6277 the <tt>nest</tt> attribute, from a function. The result is a callable
6278 function pointer lacking the nest parameter - the caller does not need
6279 to provide a value for it. Instead, the value to use is stored in
6280 advance in a "trampoline", a block of memory usually allocated
6281 on the stack, which also contains code to splice the nest value into the
6282 argument list. This is used to implement the GCC nested function address
6283 extension.
6284</p>
6285<p>
6286 For example, if the function is
6287 <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]6288 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]6289<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6290 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6291 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6292 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6293 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6294</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6295 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6296 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6297</div>
6298
6299<!-- _______________________________________________________________________ -->
6300<div class="doc_subsubsection">
6301 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6302</div>
6303<div class="doc_text">
6304<h5>Syntax:</h5>
6305<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6306declare 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]6307</pre>
6308<h5>Overview:</h5>
6309<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6310 This fills the memory pointed to by <tt>tramp</tt> with code
6311 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6312</p>
6313<h5>Arguments:</h5>
6314<p>
6315 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6316 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6317 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6318 intrinsic. Note that the size and the alignment are target-specific - LLVM
6319 currently provides no portable way of determining them, so a front-end that
6320 generates this intrinsic needs to have some target-specific knowledge.
6321 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]6322</p>
6323<h5>Semantics:</h5>
6324<p>
6325 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6326 dependent code, turning it into a function. A pointer to this function is
6327 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6328 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6329 before being called. The new function's signature is the same as that of
6330 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6331 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6332 of pointer type. Calling the new function is equivalent to calling
6333 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6334 missing <tt>nest</tt> argument. If, after calling
6335 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6336 modified, then the effect of any later call to the returned function pointer is
6337 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6338</p>
6339</div>
6340
6341<!-- ======================================================================= -->
6342<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6343 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6344</div>
6345
6346<div class="doc_text">
6347<p>
6348 These intrinsic functions expand the "universal IR" of LLVM to represent
6349 hardware constructs for atomic operations and memory synchronization. This
6350 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6351 is aimed at a low enough level to allow any programming models or APIs
6352 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6353 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6354 hardware behavior. Just as hardware provides a "universal IR" for source
6355 languages, it also provides a starting point for developing a "universal"
6356 atomic operation and synchronization IR.
6357</p>
6358<p>
6359 These do <em>not</em> form an API such as high-level threading libraries,
6360 software transaction memory systems, atomic primitives, and intrinsic
6361 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6362 application libraries. The hardware interface provided by LLVM should allow
6363 a clean implementation of all of these APIs and parallel programming models.
6364 No one model or paradigm should be selected above others unless the hardware
6365 itself ubiquitously does so.
6366
6367</p>
6368</div>
6369
6370<!-- _______________________________________________________________________ -->
6371<div class="doc_subsubsection">
6372 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6373</div>
6374<div class="doc_text">
6375<h5>Syntax:</h5>
6376<pre>
6377declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6378i1 &lt;device&gt; )
6379
6380</pre>
6381<h5>Overview:</h5>
6382<p>
6383 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6384 specific pairs of memory access types.
6385</p>
6386<h5>Arguments:</h5>
6387<p>
6388 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6389 The first four arguments enables a specific barrier as listed below. The fith
6390 argument specifies that the barrier applies to io or device or uncached memory.
6391
6392</p>
6393 <ul>
6394 <li><tt>ll</tt>: load-load barrier</li>
6395 <li><tt>ls</tt>: load-store barrier</li>
6396 <li><tt>sl</tt>: store-load barrier</li>
6397 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6398 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6399 </ul>
6400<h5>Semantics:</h5>
6401<p>
6402 This intrinsic causes the system to enforce some ordering constraints upon
6403 the loads and stores of the program. This barrier does not indicate
6404 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6405 which they occur. For any of the specified pairs of load and store operations
6406 (f.ex. load-load, or store-load), all of the first operations preceding the
6407 barrier will complete before any of the second operations succeeding the
6408 barrier begin. Specifically the semantics for each pairing is as follows:
6409</p>
6410 <ul>
6411 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6412 after the barrier begins.</li>
6413
6414 <li><tt>ls</tt>: All loads before the barrier must complete before any
6415 store after the barrier begins.</li>
6416 <li><tt>ss</tt>: All stores before the barrier must complete before any
6417 store after the barrier begins.</li>
6418 <li><tt>sl</tt>: All stores before the barrier must complete before any
6419 load after the barrier begins.</li>
6420 </ul>
6421<p>
6422 These semantics are applied with a logical "and" behavior when more than one
6423 is enabled in a single memory barrier intrinsic.
6424</p>
6425<p>
6426 Backends may implement stronger barriers than those requested when they do not
6427 support as fine grained a barrier as requested. Some architectures do not
6428 need all types of barriers and on such architectures, these become noops.
6429</p>
6430<h5>Example:</h5>
6431<pre>
6432%ptr = malloc i32
6433 store i32 4, %ptr
6434
6435%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6436 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6437 <i>; guarantee the above finishes</i>
6438 store i32 8, %ptr <i>; before this begins</i>
6439</pre>
6440</div>
6441
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6442<!-- _______________________________________________________________________ -->
6443<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6444 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6445</div>
6446<div class="doc_text">
6447<h5>Syntax:</h5>
6448<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6449 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6450 any integer bit width and for different address spaces. Not all targets
6451 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6452
6453<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6454declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6455declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6456declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6457declare 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]6458
6459</pre>
6460<h5>Overview:</h5>
6461<p>
6462 This loads a value in memory and compares it to a given value. If they are
6463 equal, it stores a new value into the memory.
6464</p>
6465<h5>Arguments:</h5>
6466<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6467 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6468 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6469 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6470 this integer type. While any bit width integer may be used, targets may only
6471 lower representations they support in hardware.
6472
6473</p>
6474<h5>Semantics:</h5>
6475<p>
6476 This entire intrinsic must be executed atomically. It first loads the value
6477 in memory pointed to by <tt>ptr</tt> and compares it with the value
6478 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6479 loaded value is yielded in all cases. This provides the equivalent of an
6480 atomic compare-and-swap operation within the SSA framework.
6481</p>
6482<h5>Examples:</h5>
6483
6484<pre>
6485%ptr = malloc i32
6486 store i32 4, %ptr
6487
6488%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6489%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6490 <i>; yields {i32}:result1 = 4</i>
6491%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6492%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6493
6494%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6495%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6496 <i>; yields {i32}:result2 = 8</i>
6497%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6498
6499%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6500</pre>
6501</div>
6502
6503<!-- _______________________________________________________________________ -->
6504<div class="doc_subsubsection">
6505 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6506</div>
6507<div class="doc_text">
6508<h5>Syntax:</h5>
6509
6510<p>
6511 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6512 integer bit width. Not all targets support all bit widths however.</p>
6513<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6514declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6515declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6516declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6517declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6518
6519</pre>
6520<h5>Overview:</h5>
6521<p>
6522 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6523 the value from memory. It then stores the value in <tt>val</tt> in the memory
6524 at <tt>ptr</tt>.
6525</p>
6526<h5>Arguments:</h5>
6527
6528<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6529 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6530 <tt>val</tt> argument and the result must be integers of the same bit width.
6531 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6532 integer type. The targets may only lower integer representations they
6533 support.
6534</p>
6535<h5>Semantics:</h5>
6536<p>
6537 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6538 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6539 equivalent of an atomic swap operation within the SSA framework.
6540
6541</p>
6542<h5>Examples:</h5>
6543<pre>
6544%ptr = malloc i32
6545 store i32 4, %ptr
6546
6547%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6548%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6549 <i>; yields {i32}:result1 = 4</i>
6550%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6551%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6552
6553%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6554%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6555 <i>; yields {i32}:result2 = 8</i>
6556
6557%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6558%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6559</pre>
6560</div>
6561
6562<!-- _______________________________________________________________________ -->
6563<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6564 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6565
6566</div>
6567<div class="doc_text">
6568<h5>Syntax:</h5>
6569<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6570 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]6571 integer bit width. Not all targets support all bit widths however.</p>
6572<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6573declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6574declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6575declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6576declare 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]6577
6578</pre>
6579<h5>Overview:</h5>
6580<p>
6581 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6582 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6583</p>
6584<h5>Arguments:</h5>
6585<p>
6586
6587 The intrinsic takes two arguments, the first a pointer to an integer value
6588 and the second an integer value. The result is also an integer value. These
6589 integer types can have any bit width, but they must all have the same bit
6590 width. The targets may only lower integer representations they support.
6591</p>
6592<h5>Semantics:</h5>
6593<p>
6594 This intrinsic does a series of operations atomically. It first loads the
6595 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6596 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6597</p>
6598
6599<h5>Examples:</h5>
6600<pre>
6601%ptr = malloc i32
6602 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6603%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6604 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6605%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6606 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6607%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6608 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6609%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6610</pre>
6611</div>
6612
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6613<!-- _______________________________________________________________________ -->
6614<div class="doc_subsubsection">
6615 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6616
6617</div>
6618<div class="doc_text">
6619<h5>Syntax:</h5>
6620<p>
6621 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]6622 any integer bit width and for different address spaces. Not all targets
6623 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6624<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6625declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6626declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6627declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6628declare 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]6629
6630</pre>
6631<h5>Overview:</h5>
6632<p>
6633 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6634 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6635</p>
6636<h5>Arguments:</h5>
6637<p>
6638
6639 The intrinsic takes two arguments, the first a pointer to an integer value
6640 and the second an integer value. The result is also an integer value. These
6641 integer types can have any bit width, but they must all have the same bit
6642 width. The targets may only lower integer representations they support.
6643</p>
6644<h5>Semantics:</h5>
6645<p>
6646 This intrinsic does a series of operations atomically. It first loads the
6647 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6648 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6649</p>
6650
6651<h5>Examples:</h5>
6652<pre>
6653%ptr = malloc i32
6654 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6655%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6656 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6657%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6658 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6659%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6660 <i>; yields {i32}:result3 = 2</i>
6661%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6662</pre>
6663</div>
6664
6665<!-- _______________________________________________________________________ -->
6666<div class="doc_subsubsection">
6667 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6668 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6669 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6670 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6671
6672</div>
6673<div class="doc_text">
6674<h5>Syntax:</h5>
6675<p>
6676 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6677 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6678 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6679 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6680<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6681declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6682declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6683declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6684declare 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]6685
6686</pre>
6687
6688<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6689declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6690declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6691declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6692declare 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]6693
6694</pre>
6695
6696<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6697declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6698declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6699declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6700declare 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]6701
6702</pre>
6703
6704<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6705declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6706declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6707declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6708declare 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]6709
6710</pre>
6711<h5>Overview:</h5>
6712<p>
6713 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6714 the value stored in memory at <tt>ptr</tt>. It yields the original value
6715 at <tt>ptr</tt>.
6716</p>
6717<h5>Arguments:</h5>
6718<p>
6719
6720 These intrinsics take two arguments, the first a pointer to an integer value
6721 and the second an integer value. The result is also an integer value. These
6722 integer types can have any bit width, but they must all have the same bit
6723 width. The targets may only lower integer representations they support.
6724</p>
6725<h5>Semantics:</h5>
6726<p>
6727 These intrinsics does a series of operations atomically. They first load the
6728 value stored at <tt>ptr</tt>. They then do the bitwise operation
6729 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6730 value stored at <tt>ptr</tt>.
6731</p>
6732
6733<h5>Examples:</h5>
6734<pre>
6735%ptr = malloc i32
6736 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6737%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6738 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6739%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6740 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6741%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6742 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6743%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6744 <i>; yields {i32}:result3 = FF</i>
6745%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6746</pre>
6747</div>
6748
6749
6750<!-- _______________________________________________________________________ -->
6751<div class="doc_subsubsection">
6752 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6753 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6754 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6755 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6756
6757</div>
6758<div class="doc_text">
6759<h5>Syntax:</h5>
6760<p>
6761 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6762 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6763 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6764 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6765 support all bit widths however.</p>
6766<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6767declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6768declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6769declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6770declare 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]6771
6772</pre>
6773
6774<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6775declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6776declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6777declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6778declare 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]6779
6780</pre>
6781
6782<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6783declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6784declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6785declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6786declare 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]6787
6788</pre>
6789
6790<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6791declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6792declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6793declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6794declare 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]6795
6796</pre>
6797<h5>Overview:</h5>
6798<p>
6799 These intrinsics takes the signed or unsigned minimum or maximum of
6800 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6801 original value at <tt>ptr</tt>.
6802</p>
6803<h5>Arguments:</h5>
6804<p>
6805
6806 These intrinsics take two arguments, the first a pointer to an integer value
6807 and the second an integer value. The result is also an integer value. These
6808 integer types can have any bit width, but they must all have the same bit
6809 width. The targets may only lower integer representations they support.
6810</p>
6811<h5>Semantics:</h5>
6812<p>
6813 These intrinsics does a series of operations atomically. They first load the
6814 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6815 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6816 the original value stored at <tt>ptr</tt>.
6817</p>
6818
6819<h5>Examples:</h5>
6820<pre>
6821%ptr = malloc i32
6822 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6823%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6824 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6825%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6826 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6827%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6828 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6829%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6830 <i>; yields {i32}:result3 = 8</i>
6831%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6832</pre>
6833</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6834
6835<!-- ======================================================================= -->
6836<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6837 <a name="int_general">General Intrinsics</a>
6838</div>
6839
6840<div class="doc_text">
6841<p> This class of intrinsics is designed to be generic and has
6842no specific purpose. </p>
6843</div>
6844
6845<!-- _______________________________________________________________________ -->
6846<div class="doc_subsubsection">
6847 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6848</div>
6849
6850<div class="doc_text">
6851
6852<h5>Syntax:</h5>
6853<pre>
6854 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6855</pre>
6856
6857<h5>Overview:</h5>
6858
6859<p>
6860The '<tt>llvm.var.annotation</tt>' intrinsic
6861</p>
6862
6863<h5>Arguments:</h5>
6864
6865<p>
6866The first argument is a pointer to a value, the second is a pointer to a
6867global string, the third is a pointer to a global string which is the source
6868file name, and the last argument is the line number.
6869</p>
6870
6871<h5>Semantics:</h5>
6872
6873<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6874This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6875This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6876annotations. These have no other defined use, they are ignored by code
6877generation and optimization.
6878</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6879</div>
6880
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6881<!-- _______________________________________________________________________ -->
6882<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6883 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6884</div>
6885
6886<div class="doc_text">
6887
6888<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6889<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6890any integer bit width.
6891</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6892<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6893 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6894 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6895 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6896 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6897 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]6898</pre>
6899
6900<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6901
6902<p>
6903The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6904</p>
6905
6906<h5>Arguments:</h5>
6907
6908<p>
6909The first argument is an integer value (result of some expression),
6910the second is a pointer to a global string, the third is a pointer to a global
6911string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6912It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6913</p>
6914
6915<h5>Semantics:</h5>
6916
6917<p>
6918This intrinsic allows annotations to be put on arbitrary expressions
6919with arbitrary strings. This can be useful for special purpose optimizations
6920that want to look for these annotations. These have no other defined use, they
6921are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6922</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6923</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6924
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6925<!-- _______________________________________________________________________ -->
6926<div class="doc_subsubsection">
6927 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6928</div>
6929
6930<div class="doc_text">
6931
6932<h5>Syntax:</h5>
6933<pre>
6934 declare void @llvm.trap()
6935</pre>
6936
6937<h5>Overview:</h5>
6938
6939<p>
6940The '<tt>llvm.trap</tt>' intrinsic
6941</p>
6942
6943<h5>Arguments:</h5>
6944
6945<p>
6946None
6947</p>
6948
6949<h5>Semantics:</h5>
6950
6951<p>
6952This intrinsics is lowered to the target dependent trap instruction. If the
6953target does not have a trap instruction, this intrinsic will be lowered to the
6954call of the abort() function.
6955</p>
6956</div>
6957
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6958<!-- _______________________________________________________________________ -->
6959<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6960 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6961</div>
6962<div class="doc_text">
6963<h5>Syntax:</h5>
6964<pre>
6965declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6966
6967</pre>
6968<h5>Overview:</h5>
6969<p>
6970 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6971 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6972 it is placed on the stack before local variables.
6973</p>
6974<h5>Arguments:</h5>
6975<p>
6976 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6977 first argument is the value loaded from the stack guard
6978 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6979 has enough space to hold the value of the guard.
6980</p>
6981<h5>Semantics:</h5>
6982<p>
6983 This intrinsic causes the prologue/epilogue inserter to force the position of
6984 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6985 stack. This is to ensure that if a local variable on the stack is overwritten,
6986 it will destroy the value of the guard. When the function exits, the guard on
6987 the stack is checked against the original guard. If they're different, then
6988 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6989</p>
6990</div>
6991
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6992<!-- *********************************************************************** -->
6993<hr>
6994<address>
6995 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6996 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6997 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6998 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]6999
7000 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7001 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7004
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