Gitiles
Code Review Sign In
gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 8100d38cfab4874ff1676b37529abc281c8665c0 / . / docs / LangRef.html
blob: 72bd76d2ae09a5ab8f3f60e595e1d5c533049816 [file] [log] [blame]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
3<html>
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>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]897declare i32 @printf(i8* noalias nocapture, ...)
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
Nick Lewycky09482712009-02-28 17:30:06 +0000[diff] [blame]1954 aggregate types to any aggregate type, as long as they have the same bit
1955 width. Vector types may also be casted to and from any other type as long as
1956 they have the same bit width. For pointers it is only valid to cast to
1957 another pointer type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1958 </dd>
1959
1960 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1961
1962 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1963 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1964 instruction, the index list may have zero or more indexes, which are required
1965 to make sense for the type of "CSTPTR".</dd>
1966
1967 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1968
1969 <dd>Perform the <a href="#i_select">select operation</a> on
1970 constants.</dd>
1971
1972 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1973 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1974
1975 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1976 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1977
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1978 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1979 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1980
1981 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1982 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1983
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1984 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1985
1986 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1987 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988
1989 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1990
1991 <dd>Perform the <a href="#i_insertelement">insertelement
1992 operation</a> on constants.</dd>
1993
1994
1995 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1996
1997 <dd>Perform the <a href="#i_shufflevector">shufflevector
1998 operation</a> on constants.</dd>
1999
2000 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2001
2002 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2003 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2004 binary</a> operations. The constraints on operands are the same as those for
2005 the corresponding instruction (e.g. no bitwise operations on floating point
2006 values are allowed).</dd>
2007</dl>
2008</div>
2009
2010<!-- *********************************************************************** -->
2011<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2012<!-- *********************************************************************** -->
2013
2014<!-- ======================================================================= -->
2015<div class="doc_subsection">
2016<a name="inlineasm">Inline Assembler Expressions</a>
2017</div>
2018
2019<div class="doc_text">
2020
2021<p>
2022LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2023Module-Level Inline Assembly</a>) through the use of a special value. This
2024value represents the inline assembler as a string (containing the instructions
2025to emit), a list of operand constraints (stored as a string), and a flag that
2026indicates whether or not the inline asm expression has side effects. An example
2027inline assembler expression is:
2028</p>
2029
2030<div class="doc_code">
2031<pre>
2032i32 (i32) asm "bswap $0", "=r,r"
2033</pre>
2034</div>
2035
2036<p>
2037Inline assembler expressions may <b>only</b> be used as the callee operand of
2038a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2039</p>
2040
2041<div class="doc_code">
2042<pre>
2043%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2044</pre>
2045</div>
2046
2047<p>
2048Inline asms with side effects not visible in the constraint list must be marked
2049as having side effects. This is done through the use of the
2050'<tt>sideeffect</tt>' keyword, like so:
2051</p>
2052
2053<div class="doc_code">
2054<pre>
2055call void asm sideeffect "eieio", ""()
2056</pre>
2057</div>
2058
2059<p>TODO: The format of the asm and constraints string still need to be
2060documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2061need to be documented). This is probably best done by reference to another
2062document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2063</p>
2064
2065</div>
2066
2067<!-- *********************************************************************** -->
2068<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2069<!-- *********************************************************************** -->
2070
2071<div class="doc_text">
2072
2073<p>The LLVM instruction set consists of several different
2074classifications of instructions: <a href="#terminators">terminator
2075instructions</a>, <a href="#binaryops">binary instructions</a>,
2076<a href="#bitwiseops">bitwise binary instructions</a>, <a
2077 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2078instructions</a>.</p>
2079
2080</div>
2081
2082<!-- ======================================================================= -->
2083<div class="doc_subsection"> <a name="terminators">Terminator
2084Instructions</a> </div>
2085
2086<div class="doc_text">
2087
2088<p>As mentioned <a href="#functionstructure">previously</a>, every
2089basic block in a program ends with a "Terminator" instruction, which
2090indicates which block should be executed after the current block is
2091finished. These terminator instructions typically yield a '<tt>void</tt>'
2092value: they produce control flow, not values (the one exception being
2093the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2094<p>There are six different terminator instructions: the '<a
2095 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2096instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2097the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2098 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2099 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2100
2101</div>
2102
2103<!-- _______________________________________________________________________ -->
2104<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2105Instruction</a> </div>
2106<div class="doc_text">
2107<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2108<pre>
2109 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]2110 ret void <i>; Return from void function</i>
2111</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2112
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2113<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2114
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2115<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2116optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2117<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2118returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2119control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2121<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2122
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2123<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2124the return value. The type of the return value must be a
2125'<a href="#t_firstclass">first class</a>' type.</p>
2126
2127<p>A function is not <a href="#wellformed">well formed</a> if
2128it it has a non-void return type and contains a '<tt>ret</tt>'
2129instruction with no return value or a return value with a type that
2130does not match its type, or if it has a void return type and contains
2131a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2132
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2133<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2134
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2135<p>When the '<tt>ret</tt>' instruction is executed, control flow
2136returns back to the calling function's context. If the caller is a "<a
2137 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2138the instruction after the call. If the caller was an "<a
2139 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2140at the beginning of the "normal" destination block. If the instruction
2141returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2142return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2143
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2144<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2145
2146<pre>
2147 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2148 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2149 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]2150</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2151
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2152<p>Note that the code generator does not yet fully support large
2153 return values. The specific sizes that are currently supported are
2154 dependent on the target. For integers, on 32-bit targets the limit
2155 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2156 For aggregate types, the current limits are dependent on the element
2157 types; for example targets are often limited to 2 total integer
2158 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2160</div>
2161<!-- _______________________________________________________________________ -->
2162<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2163<div class="doc_text">
2164<h5>Syntax:</h5>
2165<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2166</pre>
2167<h5>Overview:</h5>
2168<p>The '<tt>br</tt>' instruction is used to cause control flow to
2169transfer to a different basic block in the current function. There are
2170two forms of this instruction, corresponding to a conditional branch
2171and an unconditional branch.</p>
2172<h5>Arguments:</h5>
2173<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2174single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2175unconditional form of the '<tt>br</tt>' instruction takes a single
2176'<tt>label</tt>' value as a target.</p>
2177<h5>Semantics:</h5>
2178<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2179argument is evaluated. If the value is <tt>true</tt>, control flows
2180to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2181control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2182<h5>Example:</h5>
2183<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
2184 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2185</div>
2186<!-- _______________________________________________________________________ -->
2187<div class="doc_subsubsection">
2188 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2189</div>
2190
2191<div class="doc_text">
2192<h5>Syntax:</h5>
2193
2194<pre>
2195 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2196</pre>
2197
2198<h5>Overview:</h5>
2199
2200<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2201several different places. It is a generalization of the '<tt>br</tt>'
2202instruction, allowing a branch to occur to one of many possible
2203destinations.</p>
2204
2205
2206<h5>Arguments:</h5>
2207
2208<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2209comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2210an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2211table is not allowed to contain duplicate constant entries.</p>
2212
2213<h5>Semantics:</h5>
2214
2215<p>The <tt>switch</tt> instruction specifies a table of values and
2216destinations. When the '<tt>switch</tt>' instruction is executed, this
2217table is searched for the given value. If the value is found, control flow is
2218transfered to the corresponding destination; otherwise, control flow is
2219transfered to the default destination.</p>
2220
2221<h5>Implementation:</h5>
2222
2223<p>Depending on properties of the target machine and the particular
2224<tt>switch</tt> instruction, this instruction may be code generated in different
2225ways. For example, it could be generated as a series of chained conditional
2226branches or with a lookup table.</p>
2227
2228<h5>Example:</h5>
2229
2230<pre>
2231 <i>; Emulate a conditional br instruction</i>
2232 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2233 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2234
2235 <i>; Emulate an unconditional br instruction</i>
2236 switch i32 0, label %dest [ ]
2237
2238 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2239 switch i32 %val, label %otherwise [ i32 0, label %onzero
2240 i32 1, label %onone
2241 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2242</pre>
2243</div>
2244
2245<!-- _______________________________________________________________________ -->
2246<div class="doc_subsubsection">
2247 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2248</div>
2249
2250<div class="doc_text">
2251
2252<h5>Syntax:</h5>
2253
2254<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2255 &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]2256 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2257</pre>
2258
2259<h5>Overview:</h5>
2260
2261<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2262function, with the possibility of control flow transfer to either the
2263'<tt>normal</tt>' label or the
2264'<tt>exception</tt>' label. If the callee function returns with the
2265"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2266"normal" label. If the callee (or any indirect callees) returns with the "<a
2267href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2268continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2269
2270<h5>Arguments:</h5>
2271
2272<p>This instruction requires several arguments:</p>
2273
2274<ol>
2275 <li>
2276 The optional "cconv" marker indicates which <a href="#callingconv">calling
2277 convention</a> the call should use. If none is specified, the call defaults
2278 to using C calling conventions.
2279 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2280
2281 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2282 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2283 and '<tt>inreg</tt>' attributes are valid here.</li>
2284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2285 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2286 function value being invoked. In most cases, this is a direct function
2287 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2288 an arbitrary pointer to function value.
2289 </li>
2290
2291 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2292 function to be invoked. </li>
2293
2294 <li>'<tt>function args</tt>': argument list whose types match the function
2295 signature argument types. If the function signature indicates the function
2296 accepts a variable number of arguments, the extra arguments can be
2297 specified. </li>
2298
2299 <li>'<tt>normal label</tt>': the label reached when the called function
2300 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2301
2302 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2303 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2304
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2305 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2306 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2307 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2308</ol>
2309
2310<h5>Semantics:</h5>
2311
2312<p>This instruction is designed to operate as a standard '<tt><a
2313href="#i_call">call</a></tt>' instruction in most regards. The primary
2314difference is that it establishes an association with a label, which is used by
2315the runtime library to unwind the stack.</p>
2316
2317<p>This instruction is used in languages with destructors to ensure that proper
2318cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2319exception. Additionally, this is important for implementation of
2320'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2321
2322<h5>Example:</h5>
2323<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2324 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2325 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2326 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2327 unwind label %TestCleanup <i>; {i32}:retval set</i>
2328</pre>
2329</div>
2330
2331
2332<!-- _______________________________________________________________________ -->
2333
2334<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2335Instruction</a> </div>
2336
2337<div class="doc_text">
2338
2339<h5>Syntax:</h5>
2340<pre>
2341 unwind
2342</pre>
2343
2344<h5>Overview:</h5>
2345
2346<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2347at the first callee in the dynamic call stack which used an <a
2348href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2349primarily used to implement exception handling.</p>
2350
2351<h5>Semantics:</h5>
2352
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2353<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2354immediately halt. The dynamic call stack is then searched for the first <a
2355href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2356execution continues at the "exceptional" destination block specified by the
2357<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2358dynamic call chain, undefined behavior results.</p>
2359</div>
2360
2361<!-- _______________________________________________________________________ -->
2362
2363<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2364Instruction</a> </div>
2365
2366<div class="doc_text">
2367
2368<h5>Syntax:</h5>
2369<pre>
2370 unreachable
2371</pre>
2372
2373<h5>Overview:</h5>
2374
2375<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2376instruction is used to inform the optimizer that a particular portion of the
2377code is not reachable. This can be used to indicate that the code after a
2378no-return function cannot be reached, and other facts.</p>
2379
2380<h5>Semantics:</h5>
2381
2382<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2383</div>
2384
2385
2386
2387<!-- ======================================================================= -->
2388<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2389<div class="doc_text">
2390<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2391program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2392produce a single value. The operands might represent
2393multiple 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]2394The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2395<p>There are several different binary operators:</p>
2396</div>
2397<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2398<div class="doc_subsubsection">
2399 <a name="i_add">'<tt>add</tt>' Instruction</a>
2400</div>
2401
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2402<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2405
2406<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2407 &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]2408</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2409
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2410<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2411
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2412<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2415
2416<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2417 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2418 <a href="#t_vector">vector</a> values. Both arguments must have identical
2419 types.</p>
2420
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2421<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2423<p>The value produced is the integer or floating point sum of the two
2424operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2425
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2426<p>If an integer sum has unsigned overflow, the result returned is the
2427mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2428the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2429
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2430<p>Because LLVM integers use a two's complement representation, this
2431instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2433<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2434
2435<pre>
2436 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2437</pre>
2438</div>
2439<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2440<div class="doc_subsubsection">
2441 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2442</div>
2443
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2444<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2445
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2446<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2447
2448<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2449 &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]2450</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2452<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2453
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2454<p>The '<tt>sub</tt>' instruction returns the difference of its two
2455operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2456
2457<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2458'<tt>neg</tt>' instruction present in most other intermediate
2459representations.</p>
2460
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2461<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2462
2463<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2464 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2465 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2466 types.</p>
2467
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2468<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2469
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2470<p>The value produced is the integer or floating point difference of
2471the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2472
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2473<p>If an integer difference has unsigned overflow, the result returned is the
2474mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2475the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2476
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2477<p>Because LLVM integers use a two's complement representation, this
2478instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480<h5>Example:</h5>
2481<pre>
2482 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2483 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2484</pre>
2485</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2487<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2488<div class="doc_subsubsection">
2489 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2490</div>
2491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2495<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]2496</pre>
2497<h5>Overview:</h5>
2498<p>The '<tt>mul</tt>' instruction returns the product of its two
2499operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
2503<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2504href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2505or <a href="#t_vector">vector</a> values. Both arguments must have identical
2506types.</p>
2507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2509
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2510<p>The value produced is the integer or floating point product of the
2511two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2512
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2513<p>If the result of an integer multiplication has unsigned overflow,
2514the result returned is the mathematical result modulo
25152<sup>n</sup>, where n is the bit width of the result.</p>
2516<p>Because LLVM integers use a two's complement representation, and the
2517result is the same width as the operands, this instruction returns the
2518correct result for both signed and unsigned integers. If a full product
2519(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2520should be sign-extended or zero-extended as appropriate to the
2521width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2522<h5>Example:</h5>
2523<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2524</pre>
2525</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2527<!-- _______________________________________________________________________ -->
2528<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2529</a></div>
2530<div class="doc_text">
2531<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2532<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]2533</pre>
2534<h5>Overview:</h5>
2535<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2536operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2539
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2541<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2542values. Both arguments must have identical types.</p>
2543
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2545
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2546<p>The value produced is the unsigned integer quotient of the two operands.</p>
2547<p>Note that unsigned integer division and signed integer division are distinct
2548operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2549<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2550<h5>Example:</h5>
2551<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2552</pre>
2553</div>
2554<!-- _______________________________________________________________________ -->
2555<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2556</a> </div>
2557<div class="doc_text">
2558<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2559<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2560 &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]2561</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2563<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2564
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2565<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2566operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2568<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2569
2570<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2571<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2572values. Both arguments must have identical types.</p>
2573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2574<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2575<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]2576<p>Note that signed integer division and unsigned integer division are distinct
2577operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2578<p>Division by zero leads to undefined behavior. Overflow also leads to
2579undefined behavior; this is a rare case, but can occur, for example,
2580by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2581<h5>Example:</h5>
2582<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2583</pre>
2584</div>
2585<!-- _______________________________________________________________________ -->
2586<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2587Instruction</a> </div>
2588<div class="doc_text">
2589<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2590<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2591 &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]2592</pre>
2593<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2594
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2595<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2596operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2599
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2600<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2601<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2602of floating point values. Both arguments must have identical types.</p>
2603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2605
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2606<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2607
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2609
2610<pre>
2611 &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]2612</pre>
2613</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615<!-- _______________________________________________________________________ -->
2616<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2617</div>
2618<div class="doc_text">
2619<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2620<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]2621</pre>
2622<h5>Overview:</h5>
2623<p>The '<tt>urem</tt>' instruction returns the remainder from the
2624unsigned division of its two arguments.</p>
2625<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2626<p>The two arguments to the '<tt>urem</tt>' instruction must be
2627<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2628values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<h5>Semantics:</h5>
2630<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2631This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2632<p>Note that unsigned integer remainder and signed integer remainder are
2633distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2634<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2635<h5>Example:</h5>
2636<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2637</pre>
2638
2639</div>
2640<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2641<div class="doc_subsubsection">
2642 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2643</div>
2644
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2645<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2647<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2648
2649<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2650 &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]2651</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2655<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2656signed division of its two operands. This instruction can also take
2657<a href="#t_vector">vector</a> versions of the values in which case
2658the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2663<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2664values. Both arguments must have identical types.</p>
2665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2669has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2670operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671a value. For more information about the difference, see <a
2672 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2673Math Forum</a>. For a table of how this is implemented in various languages,
2674please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2675Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2676<p>Note that signed integer remainder and unsigned integer remainder are
2677distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2678<p>Taking the remainder of a division by zero leads to undefined behavior.
2679Overflow also leads to undefined behavior; this is a rare case, but can occur,
2680for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2681(The remainder doesn't actually overflow, but this rule lets srem be
2682implemented using instructions that return both the result of the division
2683and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2684<h5>Example:</h5>
2685<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2686</pre>
2687
2688</div>
2689<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2690<div class="doc_subsubsection">
2691 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2694
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2695<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2696<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]2697</pre>
2698<h5>Overview:</h5>
2699<p>The '<tt>frem</tt>' instruction returns the remainder from the
2700division of its two operands.</p>
2701<h5>Arguments:</h5>
2702<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2703<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2704of floating point values. Both arguments must have identical types.</p>
2705
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2706<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2707
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2708<p>This instruction returns the <i>remainder</i> of a division.
2709The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2711<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2712
2713<pre>
2714 &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]2715</pre>
2716</div>
2717
2718<!-- ======================================================================= -->
2719<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2720Operations</a> </div>
2721<div class="doc_text">
2722<p>Bitwise binary operators are used to do various forms of
2723bit-twiddling in a program. They are generally very efficient
2724instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2725instructions. They require two operands of the same type, execute an operation on them,
2726and 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]2727</div>
2728
2729<!-- _______________________________________________________________________ -->
2730<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2731Instruction</a> </div>
2732<div class="doc_text">
2733<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2734<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]2735</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2736
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2737<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2739<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2740the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2742<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2745 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2746type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2748<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2749
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2750<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2751where 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]2752equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2753If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2754corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756<h5>Example:</h5><pre>
2757 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2758 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2759 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2760 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2761 &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]2762</pre>
2763</div>
2764<!-- _______________________________________________________________________ -->
2765<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2766Instruction</a> </div>
2767<div class="doc_text">
2768<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2769<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]2770</pre>
2771
2772<h5>Overview:</h5>
2773<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2774operand shifted to the right a specified number of bits with zero fill.</p>
2775
2776<h5>Arguments:</h5>
2777<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2778<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]2779type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2780
2781<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783<p>This instruction always performs a logical shift right operation. The most
2784significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2785shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2786the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2787vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2788amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2789
2790<h5>Example:</h5>
2791<pre>
2792 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2793 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2794 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2795 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2796 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2797 &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]2798</pre>
2799</div>
2800
2801<!-- _______________________________________________________________________ -->
2802<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2803Instruction</a> </div>
2804<div class="doc_text">
2805
2806<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2807<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]2808</pre>
2809
2810<h5>Overview:</h5>
2811<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2812operand shifted to the right a specified number of bits with sign extension.</p>
2813
2814<h5>Arguments:</h5>
2815<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2816<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]2817type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2818
2819<h5>Semantics:</h5>
2820<p>This instruction always performs an arithmetic shift right operation,
2821The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2822of <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]2823larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2824arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2825corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2826
2827<h5>Example:</h5>
2828<pre>
2829 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2830 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2831 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2832 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2833 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2834 &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]2835</pre>
2836</div>
2837
2838<!-- _______________________________________________________________________ -->
2839<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2840Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2841
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2842<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2845
2846<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2847 &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]2848</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2850<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2851
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2852<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2853its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2856
2857<p>The two arguments to the '<tt>and</tt>' instruction must be
2858<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2859values. Both arguments must have identical types.</p>
2860
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2861<h5>Semantics:</h5>
2862<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2863<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2864<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2865<table border="1" cellspacing="0" cellpadding="4">
2866 <tbody>
2867 <tr>
2868 <td>In0</td>
2869 <td>In1</td>
2870 <td>Out</td>
2871 </tr>
2872 <tr>
2873 <td>0</td>
2874 <td>0</td>
2875 <td>0</td>
2876 </tr>
2877 <tr>
2878 <td>0</td>
2879 <td>1</td>
2880 <td>0</td>
2881 </tr>
2882 <tr>
2883 <td>1</td>
2884 <td>0</td>
2885 <td>0</td>
2886 </tr>
2887 <tr>
2888 <td>1</td>
2889 <td>1</td>
2890 <td>1</td>
2891 </tr>
2892 </tbody>
2893</table>
2894</div>
2895<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2896<pre>
2897 &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]2898 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2899 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2900</pre>
2901</div>
2902<!-- _______________________________________________________________________ -->
2903<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2904<div class="doc_text">
2905<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2906<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]2907</pre>
2908<h5>Overview:</h5>
2909<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2910or of its two operands.</p>
2911<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2912
2913<p>The two arguments to the '<tt>or</tt>' instruction must be
2914<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2915values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2916<h5>Semantics:</h5>
2917<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2918<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2919<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2920<table border="1" cellspacing="0" cellpadding="4">
2921 <tbody>
2922 <tr>
2923 <td>In0</td>
2924 <td>In1</td>
2925 <td>Out</td>
2926 </tr>
2927 <tr>
2928 <td>0</td>
2929 <td>0</td>
2930 <td>0</td>
2931 </tr>
2932 <tr>
2933 <td>0</td>
2934 <td>1</td>
2935 <td>1</td>
2936 </tr>
2937 <tr>
2938 <td>1</td>
2939 <td>0</td>
2940 <td>1</td>
2941 </tr>
2942 <tr>
2943 <td>1</td>
2944 <td>1</td>
2945 <td>1</td>
2946 </tr>
2947 </tbody>
2948</table>
2949</div>
2950<h5>Example:</h5>
2951<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2952 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2953 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2954</pre>
2955</div>
2956<!-- _______________________________________________________________________ -->
2957<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2958Instruction</a> </div>
2959<div class="doc_text">
2960<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2961<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]2962</pre>
2963<h5>Overview:</h5>
2964<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2965or of its two operands. The <tt>xor</tt> is used to implement the
2966"one's complement" operation, which is the "~" operator in C.</p>
2967<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2968<p>The two arguments to the '<tt>xor</tt>' instruction must be
2969<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2970values. Both arguments must have identical types.</p>
2971
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2972<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2973
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2974<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2975<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2976<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2977<table border="1" cellspacing="0" cellpadding="4">
2978 <tbody>
2979 <tr>
2980 <td>In0</td>
2981 <td>In1</td>
2982 <td>Out</td>
2983 </tr>
2984 <tr>
2985 <td>0</td>
2986 <td>0</td>
2987 <td>0</td>
2988 </tr>
2989 <tr>
2990 <td>0</td>
2991 <td>1</td>
2992 <td>1</td>
2993 </tr>
2994 <tr>
2995 <td>1</td>
2996 <td>0</td>
2997 <td>1</td>
2998 </tr>
2999 <tr>
3000 <td>1</td>
3001 <td>1</td>
3002 <td>0</td>
3003 </tr>
3004 </tbody>
3005</table>
3006</div>
3007<p> </p>
3008<h5>Example:</h5>
3009<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3010 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3011 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3012 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3013</pre>
3014</div>
3015
3016<!-- ======================================================================= -->
3017<div class="doc_subsection">
3018 <a name="vectorops">Vector Operations</a>
3019</div>
3020
3021<div class="doc_text">
3022
3023<p>LLVM supports several instructions to represent vector operations in a
3024target-independent manner. These instructions cover the element-access and
3025vector-specific operations needed to process vectors effectively. While LLVM
3026does directly support these vector operations, many sophisticated algorithms
3027will want to use target-specific intrinsics to take full advantage of a specific
3028target.</p>
3029
3030</div>
3031
3032<!-- _______________________________________________________________________ -->
3033<div class="doc_subsubsection">
3034 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3035</div>
3036
3037<div class="doc_text">
3038
3039<h5>Syntax:</h5>
3040
3041<pre>
3042 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3043</pre>
3044
3045<h5>Overview:</h5>
3046
3047<p>
3048The '<tt>extractelement</tt>' instruction extracts a single scalar
3049element from a vector at a specified index.
3050</p>
3051
3052
3053<h5>Arguments:</h5>
3054
3055<p>
3056The first operand of an '<tt>extractelement</tt>' instruction is a
3057value of <a href="#t_vector">vector</a> type. The second operand is
3058an index indicating the position from which to extract the element.
3059The index may be a variable.</p>
3060
3061<h5>Semantics:</h5>
3062
3063<p>
3064The result is a scalar of the same type as the element type of
3065<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3066<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3067results are undefined.
3068</p>
3069
3070<h5>Example:</h5>
3071
3072<pre>
3073 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3074</pre>
3075</div>
3076
3077
3078<!-- _______________________________________________________________________ -->
3079<div class="doc_subsubsection">
3080 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3081</div>
3082
3083<div class="doc_text">
3084
3085<h5>Syntax:</h5>
3086
3087<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3088 &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]3089</pre>
3090
3091<h5>Overview:</h5>
3092
3093<p>
3094The '<tt>insertelement</tt>' instruction inserts a scalar
3095element into a vector at a specified index.
3096</p>
3097
3098
3099<h5>Arguments:</h5>
3100
3101<p>
3102The first operand of an '<tt>insertelement</tt>' instruction is a
3103value of <a href="#t_vector">vector</a> type. The second operand is a
3104scalar value whose type must equal the element type of the first
3105operand. The third operand is an index indicating the position at
3106which to insert the value. The index may be a variable.</p>
3107
3108<h5>Semantics:</h5>
3109
3110<p>
3111The result is a vector of the same type as <tt>val</tt>. Its
3112element values are those of <tt>val</tt> except at position
3113<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3114exceeds the length of <tt>val</tt>, the results are undefined.
3115</p>
3116
3117<h5>Example:</h5>
3118
3119<pre>
3120 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3121</pre>
3122</div>
3123
3124<!-- _______________________________________________________________________ -->
3125<div class="doc_subsubsection">
3126 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3127</div>
3128
3129<div class="doc_text">
3130
3131<h5>Syntax:</h5>
3132
3133<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3134 &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]3135</pre>
3136
3137<h5>Overview:</h5>
3138
3139<p>
3140The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3141from two input vectors, returning a vector with the same element type as
3142the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3143</p>
3144
3145<h5>Arguments:</h5>
3146
3147<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3148The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3149with types that match each other. The third argument is a shuffle mask whose
3150element type is always 'i32'. The result of the instruction is a vector whose
3151length is the same as the shuffle mask and whose element type is the same as
3152the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153</p>
3154
3155<p>
3156The shuffle mask operand is required to be a constant vector with either
3157constant integer or undef values.
3158</p>
3159
3160<h5>Semantics:</h5>
3161
3162<p>
3163The elements of the two input vectors are numbered from left to right across
3164both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3165the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3166gets. The element selector may be undef (meaning "don't care") and the second
3167operand may be undef if performing a shuffle from only one vector.
3168</p>
3169
3170<h5>Example:</h5>
3171
3172<pre>
3173 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3174 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3175 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3176 &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]3177 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3178 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3179 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3180 &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]3181</pre>
3182</div>
3183
3184
3185<!-- ======================================================================= -->
3186<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3187 <a name="aggregateops">Aggregate Operations</a>
3188</div>
3189
3190<div class="doc_text">
3191
3192<p>LLVM supports several instructions for working with aggregate values.
3193</p>
3194
3195</div>
3196
3197<!-- _______________________________________________________________________ -->
3198<div class="doc_subsubsection">
3199 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3200</div>
3201
3202<div class="doc_text">
3203
3204<h5>Syntax:</h5>
3205
3206<pre>
3207 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3208</pre>
3209
3210<h5>Overview:</h5>
3211
3212<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3213The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3214or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3215</p>
3216
3217
3218<h5>Arguments:</h5>
3219
3220<p>
3221The first operand of an '<tt>extractvalue</tt>' instruction is a
3222value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3223type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3224in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3225'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3226</p>
3227
3228<h5>Semantics:</h5>
3229
3230<p>
3231The result is the value at the position in the aggregate specified by
3232the index operands.
3233</p>
3234
3235<h5>Example:</h5>
3236
3237<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3238 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3239</pre>
3240</div>
3241
3242
3243<!-- _______________________________________________________________________ -->
3244<div class="doc_subsubsection">
3245 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3246</div>
3247
3248<div class="doc_text">
3249
3250<h5>Syntax:</h5>
3251
3252<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3253 &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]3254</pre>
3255
3256<h5>Overview:</h5>
3257
3258<p>
3259The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3260into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3261</p>
3262
3263
3264<h5>Arguments:</h5>
3265
3266<p>
3267The first operand of an '<tt>insertvalue</tt>' instruction is a
3268value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3269The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3270The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3271indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3272indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3273'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3274The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3275by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3276</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3277
3278<h5>Semantics:</h5>
3279
3280<p>
3281The result is an aggregate of the same type as <tt>val</tt>. Its
3282value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3283specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3284</p>
3285
3286<h5>Example:</h5>
3287
3288<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3289 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3290</pre>
3291</div>
3292
3293
3294<!-- ======================================================================= -->
3295<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3296 <a name="memoryops">Memory Access and Addressing Operations</a>
3297</div>
3298
3299<div class="doc_text">
3300
3301<p>A key design point of an SSA-based representation is how it
3302represents memory. In LLVM, no memory locations are in SSA form, which
3303makes things very simple. This section describes how to read, write,
3304allocate, and free memory in LLVM.</p>
3305
3306</div>
3307
3308<!-- _______________________________________________________________________ -->
3309<div class="doc_subsubsection">
3310 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3311</div>
3312
3313<div class="doc_text">
3314
3315<h5>Syntax:</h5>
3316
3317<pre>
3318 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3319</pre>
3320
3321<h5>Overview:</h5>
3322
3323<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3324heap and returns a pointer to it. The object is always allocated in the generic
3325address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3326
3327<h5>Arguments:</h5>
3328
3329<p>The '<tt>malloc</tt>' instruction allocates
3330<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3331bytes of memory from the operating system and returns a pointer of the
3332appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3333number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3334If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3335be aligned to at least that boundary. If not specified, or if zero, the target can
3336choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3337
3338<p>'<tt>type</tt>' must be a sized type.</p>
3339
3340<h5>Semantics:</h5>
3341
3342<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3343a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3344result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3345
3346<h5>Example:</h5>
3347
3348<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3349 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3350
3351 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3352 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3353 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3354 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3355 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3356</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3357
3358<p>Note that the code generator does not yet respect the
3359 alignment value.</p>
3360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3361</div>
3362
3363<!-- _______________________________________________________________________ -->
3364<div class="doc_subsubsection">
3365 <a name="i_free">'<tt>free</tt>' Instruction</a>
3366</div>
3367
3368<div class="doc_text">
3369
3370<h5>Syntax:</h5>
3371
3372<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3373 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3374</pre>
3375
3376<h5>Overview:</h5>
3377
3378<p>The '<tt>free</tt>' instruction returns memory back to the unused
3379memory heap to be reallocated in the future.</p>
3380
3381<h5>Arguments:</h5>
3382
3383<p>'<tt>value</tt>' shall be a pointer value that points to a value
3384that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3385instruction.</p>
3386
3387<h5>Semantics:</h5>
3388
3389<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3390after this instruction executes. If the pointer is null, the operation
3391is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3392
3393<h5>Example:</h5>
3394
3395<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3396 %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]3397 free [4 x i8]* %array
3398</pre>
3399</div>
3400
3401<!-- _______________________________________________________________________ -->
3402<div class="doc_subsubsection">
3403 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3404</div>
3405
3406<div class="doc_text">
3407
3408<h5>Syntax:</h5>
3409
3410<pre>
3411 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3412</pre>
3413
3414<h5>Overview:</h5>
3415
3416<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3417currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3418returns to its caller. The object is always allocated in the generic address
3419space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3420
3421<h5>Arguments:</h5>
3422
3423<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3424bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3425appropriate type to the program. If "NumElements" is specified, it is the
3426number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3427If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3428to be aligned to at least that boundary. If not specified, or if zero, the target
3429can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3430
3431<p>'<tt>type</tt>' may be any sized type.</p>
3432
3433<h5>Semantics:</h5>
3434
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3435<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3436there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437memory is automatically released when the function returns. The '<tt>alloca</tt>'
3438instruction is commonly used to represent automatic variables that must
3439have an address available. When the function returns (either with the <tt><a
3440 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]3441instructions), the memory is reclaimed. Allocating zero bytes
3442is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3443
3444<h5>Example:</h5>
3445
3446<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3447 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3448 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3449 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3450 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3451</pre>
3452</div>
3453
3454<!-- _______________________________________________________________________ -->
3455<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3456Instruction</a> </div>
3457<div class="doc_text">
3458<h5>Syntax:</h5>
3459<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>
3460<h5>Overview:</h5>
3461<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3462<h5>Arguments:</h5>
3463<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3464address from which to load. The pointer must point to a <a
3465 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3466marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3467the number or order of execution of this <tt>load</tt> with other
3468volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3469instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3470<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3471The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3472(that is, the alignment of the memory address). A value of 0 or an
3473omitted "align" argument means that the operation has the preferential
3474alignment for the target. It is the responsibility of the code emitter
3475to ensure that the alignment information is correct. Overestimating
3476the alignment results in an undefined behavior. Underestimating the
3477alignment may produce less efficient code. An alignment of 1 is always
3478safe.
3479</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3480<h5>Semantics:</h5>
3481<p>The location of memory pointed to is loaded.</p>
3482<h5>Examples:</h5>
3483<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3484 <a
3485 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3486 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3487</pre>
3488</div>
3489<!-- _______________________________________________________________________ -->
3490<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3491Instruction</a> </div>
3492<div class="doc_text">
3493<h5>Syntax:</h5>
3494<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3495 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3496</pre>
3497<h5>Overview:</h5>
3498<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3499<h5>Arguments:</h5>
3500<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3501to 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]3502operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3503of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3504operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3505optimizer is not allowed to modify the number or order of execution of
3506this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3507 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3508<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3509The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3510(that is, the alignment of the memory address). A value of 0 or an
3511omitted "align" argument means that the operation has the preferential
3512alignment for the target. It is the responsibility of the code emitter
3513to ensure that the alignment information is correct. Overestimating
3514the alignment results in an undefined behavior. Underestimating the
3515alignment may produce less efficient code. An alignment of 1 is always
3516safe.
3517</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3518<h5>Semantics:</h5>
3519<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3520at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3521<h5>Example:</h5>
3522<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3523 store i32 3, i32* %ptr <i>; yields {void}</i>
3524 %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]3525</pre>
3526</div>
3527
3528<!-- _______________________________________________________________________ -->
3529<div class="doc_subsubsection">
3530 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3531</div>
3532
3533<div class="doc_text">
3534<h5>Syntax:</h5>
3535<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3536 &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]3537</pre>
3538
3539<h5>Overview:</h5>
3540
3541<p>
3542The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3543subelement of an aggregate data structure. It performs address calculation only
3544and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3545
3546<h5>Arguments:</h5>
3547
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3548<p>The first argument is always a pointer, and forms the basis of the
3549calculation. The remaining arguments are indices, that indicate which of the
3550elements of the aggregate object are indexed. The interpretation of each index
3551is dependent on the type being indexed into. The first index always indexes the
3552pointer value given as the first argument, the second index indexes a value of
3553the type pointed to (not necessarily the value directly pointed to, since the
3554first index can be non-zero), etc. The first type indexed into must be a pointer
3555value, subsequent types can be arrays, vectors and structs. Note that subsequent
3556types being indexed into can never be pointers, since that would require loading
3557the pointer before continuing calculation.</p>
3558
3559<p>The type of each index argument depends on the type it is indexing into.
3560When indexing into a (packed) structure, only <tt>i32</tt> integer
3561<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3562only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3563will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3564
3565<p>For example, let's consider a C code fragment and how it gets
3566compiled to LLVM:</p>
3567
3568<div class="doc_code">
3569<pre>
3570struct RT {
3571 char A;
3572 int B[10][20];
3573 char C;
3574};
3575struct ST {
3576 int X;
3577 double Y;
3578 struct RT Z;
3579};
3580
3581int *foo(struct ST *s) {
3582 return &amp;s[1].Z.B[5][13];
3583}
3584</pre>
3585</div>
3586
3587<p>The LLVM code generated by the GCC frontend is:</p>
3588
3589<div class="doc_code">
3590<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3591%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3592%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3593
3594define i32* %foo(%ST* %s) {
3595entry:
3596 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3597 ret i32* %reg
3598}
3599</pre>
3600</div>
3601
3602<h5>Semantics:</h5>
3603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3604<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3605type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3606}</tt>' type, a structure. The second index indexes into the third element of
3607the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3608i8 }</tt>' type, another structure. The third index indexes into the second
3609element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3610array. The two dimensions of the array are subscripted into, yielding an
3611'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3612to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3613
3614<p>Note that it is perfectly legal to index partially through a
3615structure, returning a pointer to an inner element. Because of this,
3616the LLVM code for the given testcase is equivalent to:</p>
3617
3618<pre>
3619 define i32* %foo(%ST* %s) {
3620 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3621 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3622 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3623 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3624 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3625 ret i32* %t5
3626 }
3627</pre>
3628
3629<p>Note that it is undefined to access an array out of bounds: array and
3630pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3631The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3632defined to be accessible as variable length arrays, which requires access
3633beyond the zero'th element.</p>
3634
3635<p>The getelementptr instruction is often confusing. For some more insight
3636into how it works, see <a href="GetElementPtr.html">the getelementptr
3637FAQ</a>.</p>
3638
3639<h5>Example:</h5>
3640
3641<pre>
3642 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3643 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3644 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3645 %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]3646 <i>; yields i8*:eptr</i>
3647 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3648</pre>
3649</div>
3650
3651<!-- ======================================================================= -->
3652<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3653</div>
3654<div class="doc_text">
3655<p>The instructions in this category are the conversion instructions (casting)
3656which all take a single operand and a type. They perform various bit conversions
3657on the operand.</p>
3658</div>
3659
3660<!-- _______________________________________________________________________ -->
3661<div class="doc_subsubsection">
3662 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3663</div>
3664<div class="doc_text">
3665
3666<h5>Syntax:</h5>
3667<pre>
3668 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3669</pre>
3670
3671<h5>Overview:</h5>
3672<p>
3673The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3674</p>
3675
3676<h5>Arguments:</h5>
3677<p>
3678The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3679be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3680and type of the result, which must be an <a href="#t_integer">integer</a>
3681type. The bit size of <tt>value</tt> must be larger than the bit size of
3682<tt>ty2</tt>. Equal sized types are not allowed.</p>
3683
3684<h5>Semantics:</h5>
3685<p>
3686The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3687and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3688larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3689It will always truncate bits.</p>
3690
3691<h5>Example:</h5>
3692<pre>
3693 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3694 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3695 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3696</pre>
3697</div>
3698
3699<!-- _______________________________________________________________________ -->
3700<div class="doc_subsubsection">
3701 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3702</div>
3703<div class="doc_text">
3704
3705<h5>Syntax:</h5>
3706<pre>
3707 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3708</pre>
3709
3710<h5>Overview:</h5>
3711<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3712<tt>ty2</tt>.</p>
3713
3714
3715<h5>Arguments:</h5>
3716<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3717<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3718also be of <a href="#t_integer">integer</a> type. The bit size of the
3719<tt>value</tt> must be smaller than the bit size of the destination type,
3720<tt>ty2</tt>.</p>
3721
3722<h5>Semantics:</h5>
3723<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3724bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3725
3726<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3727
3728<h5>Example:</h5>
3729<pre>
3730 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3731 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3732</pre>
3733</div>
3734
3735<!-- _______________________________________________________________________ -->
3736<div class="doc_subsubsection">
3737 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3738</div>
3739<div class="doc_text">
3740
3741<h5>Syntax:</h5>
3742<pre>
3743 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3744</pre>
3745
3746<h5>Overview:</h5>
3747<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3748
3749<h5>Arguments:</h5>
3750<p>
3751The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3752<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3753also be of <a href="#t_integer">integer</a> type. The bit size of the
3754<tt>value</tt> must be smaller than the bit size of the destination type,
3755<tt>ty2</tt>.</p>
3756
3757<h5>Semantics:</h5>
3758<p>
3759The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3760bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3761the type <tt>ty2</tt>.</p>
3762
3763<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3764
3765<h5>Example:</h5>
3766<pre>
3767 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3768 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3769</pre>
3770</div>
3771
3772<!-- _______________________________________________________________________ -->
3773<div class="doc_subsubsection">
3774 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3775</div>
3776
3777<div class="doc_text">
3778
3779<h5>Syntax:</h5>
3780
3781<pre>
3782 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3783</pre>
3784
3785<h5>Overview:</h5>
3786<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3787<tt>ty2</tt>.</p>
3788
3789
3790<h5>Arguments:</h5>
3791<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3792 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3793cast it to. The size of <tt>value</tt> must be larger than the size of
3794<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3795<i>no-op cast</i>.</p>
3796
3797<h5>Semantics:</h5>
3798<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3799<a href="#t_floating">floating point</a> type to a smaller
3800<a href="#t_floating">floating point</a> type. If the value cannot fit within
3801the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3802
3803<h5>Example:</h5>
3804<pre>
3805 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3806 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3807</pre>
3808</div>
3809
3810<!-- _______________________________________________________________________ -->
3811<div class="doc_subsubsection">
3812 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3813</div>
3814<div class="doc_text">
3815
3816<h5>Syntax:</h5>
3817<pre>
3818 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3819</pre>
3820
3821<h5>Overview:</h5>
3822<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3823floating point value.</p>
3824
3825<h5>Arguments:</h5>
3826<p>The '<tt>fpext</tt>' instruction takes a
3827<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3828and a <a href="#t_floating">floating point</a> type to cast it to. The source
3829type must be smaller than the destination type.</p>
3830
3831<h5>Semantics:</h5>
3832<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3833<a href="#t_floating">floating point</a> type to a larger
3834<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3835used to make a <i>no-op cast</i> because it always changes bits. Use
3836<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3837
3838<h5>Example:</h5>
3839<pre>
3840 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3841 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3842</pre>
3843</div>
3844
3845<!-- _______________________________________________________________________ -->
3846<div class="doc_subsubsection">
3847 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3848</div>
3849<div class="doc_text">
3850
3851<h5>Syntax:</h5>
3852<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3853 &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]3854</pre>
3855
3856<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3857<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3858unsigned integer equivalent of type <tt>ty2</tt>.
3859</p>
3860
3861<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3862<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]3863scalar or vector <a href="#t_floating">floating point</a> value, and a type
3864to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3865type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3866vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3867
3868<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3869<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3870<a href="#t_floating">floating point</a> operand into the nearest (rounding
3871towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3872the results are undefined.</p>
3873
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3874<h5>Example:</h5>
3875<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3876 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3877 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3878 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3879</pre>
3880</div>
3881
3882<!-- _______________________________________________________________________ -->
3883<div class="doc_subsubsection">
3884 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3885</div>
3886<div class="doc_text">
3887
3888<h5>Syntax:</h5>
3889<pre>
3890 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3891</pre>
3892
3893<h5>Overview:</h5>
3894<p>The '<tt>fptosi</tt>' instruction converts
3895<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3896</p>
3897
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898<h5>Arguments:</h5>
3899<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]3900scalar or vector <a href="#t_floating">floating point</a> value, and a type
3901to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3902type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3903vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3904
3905<h5>Semantics:</h5>
3906<p>The '<tt>fptosi</tt>' instruction converts its
3907<a href="#t_floating">floating point</a> operand into the nearest (rounding
3908towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3909the results are undefined.</p>
3910
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3911<h5>Example:</h5>
3912<pre>
3913 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3914 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3915 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3916</pre>
3917</div>
3918
3919<!-- _______________________________________________________________________ -->
3920<div class="doc_subsubsection">
3921 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3922</div>
3923<div class="doc_text">
3924
3925<h5>Syntax:</h5>
3926<pre>
3927 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3928</pre>
3929
3930<h5>Overview:</h5>
3931<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3932integer and converts that value to the <tt>ty2</tt> type.</p>
3933
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3935<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3936scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3937to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3938type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3939floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3940
3941<h5>Semantics:</h5>
3942<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3943integer quantity and converts it to the corresponding floating point value. If
3944the value cannot fit in the floating point value, the results are undefined.</p>
3945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3946<h5>Example:</h5>
3947<pre>
3948 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3949 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3950</pre>
3951</div>
3952
3953<!-- _______________________________________________________________________ -->
3954<div class="doc_subsubsection">
3955 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3956</div>
3957<div class="doc_text">
3958
3959<h5>Syntax:</h5>
3960<pre>
3961 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3962</pre>
3963
3964<h5>Overview:</h5>
3965<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3966integer and converts that value to the <tt>ty2</tt> type.</p>
3967
3968<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3969<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3970scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3971to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3972type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3973floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3974
3975<h5>Semantics:</h5>
3976<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3977integer quantity and converts it to the corresponding floating point value. If
3978the value cannot fit in the floating point value, the results are undefined.</p>
3979
3980<h5>Example:</h5>
3981<pre>
3982 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3983 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3984</pre>
3985</div>
3986
3987<!-- _______________________________________________________________________ -->
3988<div class="doc_subsubsection">
3989 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3990</div>
3991<div class="doc_text">
3992
3993<h5>Syntax:</h5>
3994<pre>
3995 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3996</pre>
3997
3998<h5>Overview:</h5>
3999<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4000the integer type <tt>ty2</tt>.</p>
4001
4002<h5>Arguments:</h5>
4003<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4004must 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]4005<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]4006
4007<h5>Semantics:</h5>
4008<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4009<tt>ty2</tt> by interpreting the pointer value as an integer and either
4010truncating or zero extending that value to the size of the integer type. If
4011<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4012<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4013are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4014change.</p>
4015
4016<h5>Example:</h5>
4017<pre>
4018 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4019 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4020</pre>
4021</div>
4022
4023<!-- _______________________________________________________________________ -->
4024<div class="doc_subsubsection">
4025 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4026</div>
4027<div class="doc_text">
4028
4029<h5>Syntax:</h5>
4030<pre>
4031 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4032</pre>
4033
4034<h5>Overview:</h5>
4035<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4036a pointer type, <tt>ty2</tt>.</p>
4037
4038<h5>Arguments:</h5>
4039<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4040value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4041<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4042
4043<h5>Semantics:</h5>
4044<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4045<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4046the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4047size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4048the size of a pointer then a zero extension is done. If they are the same size,
4049nothing is done (<i>no-op cast</i>).</p>
4050
4051<h5>Example:</h5>
4052<pre>
4053 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4054 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4055 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4056</pre>
4057</div>
4058
4059<!-- _______________________________________________________________________ -->
4060<div class="doc_subsubsection">
4061 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4062</div>
4063<div class="doc_text">
4064
4065<h5>Syntax:</h5>
4066<pre>
4067 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4068</pre>
4069
4070<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4071
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4072<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4073<tt>ty2</tt> without changing any bits.</p>
4074
4075<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4076
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4077<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4078a non-aggregate first class value, and a type to cast it to, which must also be
4079a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4080<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4081and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4082type is a pointer, the destination type must also be a pointer. This
4083instruction supports bitwise conversion of vectors to integers and to vectors
4084of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085
4086<h5>Semantics:</h5>
4087<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4088<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4089this conversion. The conversion is done as if the <tt>value</tt> had been
4090stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4091converted to other pointer types with this instruction. To convert pointers to
4092other types, use the <a href="#i_inttoptr">inttoptr</a> or
4093<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4094
4095<h5>Example:</h5>
4096<pre>
4097 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4098 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4099 %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]4100</pre>
4101</div>
4102
4103<!-- ======================================================================= -->
4104<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4105<div class="doc_text">
4106<p>The instructions in this category are the "miscellaneous"
4107instructions, which defy better classification.</p>
4108</div>
4109
4110<!-- _______________________________________________________________________ -->
4111<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4112</div>
4113<div class="doc_text">
4114<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4115<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]4116</pre>
4117<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4118<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4119a vector of boolean values based on comparison
4120of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4121<h5>Arguments:</h5>
4122<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4123the condition code indicating the kind of comparison to perform. It is not
4124a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4125</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4126<ol>
4127 <li><tt>eq</tt>: equal</li>
4128 <li><tt>ne</tt>: not equal </li>
4129 <li><tt>ugt</tt>: unsigned greater than</li>
4130 <li><tt>uge</tt>: unsigned greater or equal</li>
4131 <li><tt>ult</tt>: unsigned less than</li>
4132 <li><tt>ule</tt>: unsigned less or equal</li>
4133 <li><tt>sgt</tt>: signed greater than</li>
4134 <li><tt>sge</tt>: signed greater or equal</li>
4135 <li><tt>slt</tt>: signed less than</li>
4136 <li><tt>sle</tt>: signed less or equal</li>
4137</ol>
4138<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4139<a href="#t_pointer">pointer</a>
4140or integer <a href="#t_vector">vector</a> typed.
4141They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4142<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4143<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]4144the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4145yields 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]4146</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147<ol>
4148 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4149 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4150 </li>
4151 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4152 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4154 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4155 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4156 <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]4157 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4158 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4159 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4160 <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]4161 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4162 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4163 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4164 <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]4165 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4166 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4167 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4168 <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]4169</ol>
4170<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4171values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4172<p>If the operands are integer vectors, then they are compared
4173element by element. The result is an <tt>i1</tt> vector with
4174the same number of elements as the values being compared.
4175Otherwise, the result is an <tt>i1</tt>.
4176</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4177
4178<h5>Example:</h5>
4179<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4180 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4181 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4182 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4183 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4184 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4185</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4186
4187<p>Note that the code generator does not yet support vector types with
4188 the <tt>icmp</tt> instruction.</p>
4189
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4190</div>
4191
4192<!-- _______________________________________________________________________ -->
4193<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4194</div>
4195<div class="doc_text">
4196<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4197<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]4198</pre>
4199<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4200<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4201or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4202of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4203<p>
4204If the operands are floating point scalars, then the result
4205type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4206</p>
4207<p>If the operands are floating point vectors, then the result type
4208is a vector of boolean with the same number of elements as the
4209operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210<h5>Arguments:</h5>
4211<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4212the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4213a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4214<ol>
4215 <li><tt>false</tt>: no comparison, always returns false</li>
4216 <li><tt>oeq</tt>: ordered and equal</li>
4217 <li><tt>ogt</tt>: ordered and greater than </li>
4218 <li><tt>oge</tt>: ordered and greater than or equal</li>
4219 <li><tt>olt</tt>: ordered and less than </li>
4220 <li><tt>ole</tt>: ordered and less than or equal</li>
4221 <li><tt>one</tt>: ordered and not equal</li>
4222 <li><tt>ord</tt>: ordered (no nans)</li>
4223 <li><tt>ueq</tt>: unordered or equal</li>
4224 <li><tt>ugt</tt>: unordered or greater than </li>
4225 <li><tt>uge</tt>: unordered or greater than or equal</li>
4226 <li><tt>ult</tt>: unordered or less than </li>
4227 <li><tt>ule</tt>: unordered or less than or equal</li>
4228 <li><tt>une</tt>: unordered or not equal</li>
4229 <li><tt>uno</tt>: unordered (either nans)</li>
4230 <li><tt>true</tt>: no comparison, always returns true</li>
4231</ol>
4232<p><i>Ordered</i> means that neither operand is a QNAN while
4233<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4234<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4235either a <a href="#t_floating">floating point</a> type
4236or a <a href="#t_vector">vector</a> of floating point type.
4237They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4239<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4240according to the condition code given as <tt>cond</tt>.
4241If the operands are vectors, then the vectors are compared
4242element by element.
4243Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4244always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245<ol>
4246 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4247 <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]4248 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249 <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]4250 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4251 <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]4252 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253 <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]4254 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4255 <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]4256 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4257 <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]4258 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4259 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4260 <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]4261 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4262 <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]4263 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264 <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]4265 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4266 <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]4267 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268 <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]4269 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4270 <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]4271 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4272 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4273 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4274</ol>
4275
4276<h5>Example:</h5>
4277<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]4278 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4279 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4280 &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]4281</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4282
4283<p>Note that the code generator does not yet support vector types with
4284 the <tt>fcmp</tt> instruction.</p>
4285
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4286</div>
4287
4288<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4289<div class="doc_subsubsection">
4290 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4291</div>
4292<div class="doc_text">
4293<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4294<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]4295</pre>
4296<h5>Overview:</h5>
4297<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4298element-wise comparison of its two integer vector operands.</p>
4299<h5>Arguments:</h5>
4300<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4301the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4302a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4303<ol>
4304 <li><tt>eq</tt>: equal</li>
4305 <li><tt>ne</tt>: not equal </li>
4306 <li><tt>ugt</tt>: unsigned greater than</li>
4307 <li><tt>uge</tt>: unsigned greater or equal</li>
4308 <li><tt>ult</tt>: unsigned less than</li>
4309 <li><tt>ule</tt>: unsigned less or equal</li>
4310 <li><tt>sgt</tt>: signed greater than</li>
4311 <li><tt>sge</tt>: signed greater or equal</li>
4312 <li><tt>slt</tt>: signed less than</li>
4313 <li><tt>sle</tt>: signed less or equal</li>
4314</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4315<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4316<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4317<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4318<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4319according to the condition code given as <tt>cond</tt>. The comparison yields a
4320<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4321identical type as the values being compared. The most significant bit in each
4322element is 1 if the element-wise comparison evaluates to true, and is 0
4323otherwise. All other bits of the result are undefined. The condition codes
4324are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4325instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4326
4327<h5>Example:</h5>
4328<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4329 &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>
4330 &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]4331</pre>
4332</div>
4333
4334<!-- _______________________________________________________________________ -->
4335<div class="doc_subsubsection">
4336 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4337</div>
4338<div class="doc_text">
4339<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4340<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]4341<h5>Overview:</h5>
4342<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4343element-wise comparison of its two floating point vector operands. The output
4344elements have the same width as the input elements.</p>
4345<h5>Arguments:</h5>
4346<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4347the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4348a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4349<ol>
4350 <li><tt>false</tt>: no comparison, always returns false</li>
4351 <li><tt>oeq</tt>: ordered and equal</li>
4352 <li><tt>ogt</tt>: ordered and greater than </li>
4353 <li><tt>oge</tt>: ordered and greater than or equal</li>
4354 <li><tt>olt</tt>: ordered and less than </li>
4355 <li><tt>ole</tt>: ordered and less than or equal</li>
4356 <li><tt>one</tt>: ordered and not equal</li>
4357 <li><tt>ord</tt>: ordered (no nans)</li>
4358 <li><tt>ueq</tt>: unordered or equal</li>
4359 <li><tt>ugt</tt>: unordered or greater than </li>
4360 <li><tt>uge</tt>: unordered or greater than or equal</li>
4361 <li><tt>ult</tt>: unordered or less than </li>
4362 <li><tt>ule</tt>: unordered or less than or equal</li>
4363 <li><tt>une</tt>: unordered or not equal</li>
4364 <li><tt>uno</tt>: unordered (either nans)</li>
4365 <li><tt>true</tt>: no comparison, always returns true</li>
4366</ol>
4367<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4368<a href="#t_floating">floating point</a> typed. They must also be identical
4369types.</p>
4370<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4371<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4372according to the condition code given as <tt>cond</tt>. The comparison yields a
4373<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4374an identical number of elements as the values being compared, and each element
4375having identical with to the width of the floating point elements. The most
4376significant bit in each element is 1 if the element-wise comparison evaluates to
4377true, and is 0 otherwise. All other bits of the result are undefined. The
4378condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4379<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4380
4381<h5>Example:</h5>
4382<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4383 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4384 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4385
4386 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4387 &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]4388</pre>
4389</div>
4390
4391<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4392<div class="doc_subsubsection">
4393 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4394</div>
4395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4396<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4398<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4400<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4401<h5>Overview:</h5>
4402<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4403the SSA graph representing the function.</p>
4404<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4406<p>The type of the incoming values is specified with the first type
4407field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4408as arguments, with one pair for each predecessor basic block of the
4409current block. Only values of <a href="#t_firstclass">first class</a>
4410type may be used as the value arguments to the PHI node. Only labels
4411may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413<p>There must be no non-phi instructions between the start of a basic
4414block and the PHI instructions: i.e. PHI instructions must be first in
4415a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4417<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4419<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4420specified by the pair corresponding to the predecessor basic block that executed
4421just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4422
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4423<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4424<pre>
4425Loop: ; Infinite loop that counts from 0 on up...
4426 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4427 %nextindvar = add i32 %indvar, 1
4428 br label %Loop
4429</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430</div>
4431
4432<!-- _______________________________________________________________________ -->
4433<div class="doc_subsubsection">
4434 <a name="i_select">'<tt>select</tt>' Instruction</a>
4435</div>
4436
4437<div class="doc_text">
4438
4439<h5>Syntax:</h5>
4440
4441<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4442 &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>
4443
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4444 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4445</pre>
4446
4447<h5>Overview:</h5>
4448
4449<p>
4450The '<tt>select</tt>' instruction is used to choose one value based on a
4451condition, without branching.
4452</p>
4453
4454
4455<h5>Arguments:</h5>
4456
4457<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4458The '<tt>select</tt>' instruction requires an 'i1' value or
4459a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4460condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4461type. If the val1/val2 are vectors and
4462the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4463individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4464</p>
4465
4466<h5>Semantics:</h5>
4467
4468<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4469If 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]4470value argument; otherwise, it returns the second value argument.
4471</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4472<p>
4473If the condition is a vector of i1, then the value arguments must
4474be vectors of the same size, and the selection is done element
4475by element.
4476</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4477
4478<h5>Example:</h5>
4479
4480<pre>
4481 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4482</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4483
4484<p>Note that the code generator does not yet support conditions
4485 with vector type.</p>
4486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4487</div>
4488
4489
4490<!-- _______________________________________________________________________ -->
4491<div class="doc_subsubsection">
4492 <a name="i_call">'<tt>call</tt>' Instruction</a>
4493</div>
4494
4495<div class="doc_text">
4496
4497<h5>Syntax:</h5>
4498<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4499 &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]4500</pre>
4501
4502<h5>Overview:</h5>
4503
4504<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4505
4506<h5>Arguments:</h5>
4507
4508<p>This instruction requires several arguments:</p>
4509
4510<ol>
4511 <li>
4512 <p>The optional "tail" marker indicates whether the callee function accesses
4513 any allocas or varargs in the caller. If the "tail" marker is present, the
4514 function call is eligible for tail call optimization. Note that calls may
4515 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4516 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4517 </li>
4518 <li>
4519 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4520 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4521 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4522 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4523
4524 <li>
4525 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4526 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4527 and '<tt>inreg</tt>' attributes are valid here.</p>
4528 </li>
4529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4530 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4531 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4532 the type of the return value. Functions that return no value are marked
4533 <tt><a href="#t_void">void</a></tt>.</p>
4534 </li>
4535 <li>
4536 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4537 value being invoked. The argument types must match the types implied by
4538 this signature. This type can be omitted if the function is not varargs
4539 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4540 </li>
4541 <li>
4542 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4543 be invoked. In most cases, this is a direct function invocation, but
4544 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4545 to function value.</p>
4546 </li>
4547 <li>
4548 <p>'<tt>function args</tt>': argument list whose types match the
4549 function signature argument types. All arguments must be of
4550 <a href="#t_firstclass">first class</a> type. If the function signature
4551 indicates the function accepts a variable number of arguments, the extra
4552 arguments can be specified.</p>
4553 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4554 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4555 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4556 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4557 '<tt>readnone</tt>' attributes are valid here.</p>
4558 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4559</ol>
4560
4561<h5>Semantics:</h5>
4562
4563<p>The '<tt>call</tt>' instruction is used to cause control flow to
4564transfer to a specified function, with its incoming arguments bound to
4565the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4566instruction in the called function, control flow continues with the
4567instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4568function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4569
4570<h5>Example:</h5>
4571
4572<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4573 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4574 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4575 %X = tail call i32 @foo() <i>; yields i32</i>
4576 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4577 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4578
4579 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4580 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4581 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4582 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4583 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4584 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4585</pre>
4586
4587</div>
4588
4589<!-- _______________________________________________________________________ -->
4590<div class="doc_subsubsection">
4591 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4592</div>
4593
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
4597
4598<pre>
4599 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4600</pre>
4601
4602<h5>Overview:</h5>
4603
4604<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4605the "variable argument" area of a function call. It is used to implement the
4606<tt>va_arg</tt> macro in C.</p>
4607
4608<h5>Arguments:</h5>
4609
4610<p>This instruction takes a <tt>va_list*</tt> value and the type of
4611the argument. It returns a value of the specified argument type and
4612increments the <tt>va_list</tt> to point to the next argument. The
4613actual type of <tt>va_list</tt> is target specific.</p>
4614
4615<h5>Semantics:</h5>
4616
4617<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4618type from the specified <tt>va_list</tt> and causes the
4619<tt>va_list</tt> to point to the next argument. For more information,
4620see the variable argument handling <a href="#int_varargs">Intrinsic
4621Functions</a>.</p>
4622
4623<p>It is legal for this instruction to be called in a function which does not
4624take a variable number of arguments, for example, the <tt>vfprintf</tt>
4625function.</p>
4626
4627<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4628href="#intrinsics">intrinsic function</a> because it takes a type as an
4629argument.</p>
4630
4631<h5>Example:</h5>
4632
4633<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4634
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4635<p>Note that the code generator does not yet fully support va_arg
4636 on many targets. Also, it does not currently support va_arg with
4637 aggregate types on any target.</p>
4638
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4639</div>
4640
4641<!-- *********************************************************************** -->
4642<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4643<!-- *********************************************************************** -->
4644
4645<div class="doc_text">
4646
4647<p>LLVM supports the notion of an "intrinsic function". These functions have
4648well known names and semantics and are required to follow certain restrictions.
4649Overall, these intrinsics represent an extension mechanism for the LLVM
4650language that does not require changing all of the transformations in LLVM when
4651adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4652
4653<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4654prefix is reserved in LLVM for intrinsic names; thus, function names may not
4655begin with this prefix. Intrinsic functions must always be external functions:
4656you cannot define the body of intrinsic functions. Intrinsic functions may
4657only be used in call or invoke instructions: it is illegal to take the address
4658of an intrinsic function. Additionally, because intrinsic functions are part
4659of the LLVM language, it is required if any are added that they be documented
4660here.</p>
4661
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4662<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4663a family of functions that perform the same operation but on different data
4664types. Because LLVM can represent over 8 million different integer types,
4665overloading is used commonly to allow an intrinsic function to operate on any
4666integer type. One or more of the argument types or the result type can be
4667overloaded to accept any integer type. Argument types may also be defined as
4668exactly matching a previous argument's type or the result type. This allows an
4669intrinsic function which accepts multiple arguments, but needs all of them to
4670be of the same type, to only be overloaded with respect to a single argument or
4671the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4672
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4673<p>Overloaded intrinsics will have the names of its overloaded argument types
4674encoded into its function name, each preceded by a period. Only those types
4675which are overloaded result in a name suffix. Arguments whose type is matched
4676against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4677take an integer of any width and returns an integer of exactly the same integer
4678width. This leads to a family of functions such as
4679<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4680Only one type, the return type, is overloaded, and only one type suffix is
4681required. Because the argument's type is matched against the return type, it
4682does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4683
4684<p>To learn how to add an intrinsic function, please see the
4685<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4686</p>
4687
4688</div>
4689
4690<!-- ======================================================================= -->
4691<div class="doc_subsection">
4692 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4693</div>
4694
4695<div class="doc_text">
4696
4697<p>Variable argument support is defined in LLVM with the <a
4698 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4699intrinsic functions. These functions are related to the similarly
4700named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4701
4702<p>All of these functions operate on arguments that use a
4703target-specific value type "<tt>va_list</tt>". The LLVM assembly
4704language reference manual does not define what this type is, so all
4705transformations should be prepared to handle these functions regardless of
4706the type used.</p>
4707
4708<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4709instruction and the variable argument handling intrinsic functions are
4710used.</p>
4711
4712<div class="doc_code">
4713<pre>
4714define i32 @test(i32 %X, ...) {
4715 ; Initialize variable argument processing
4716 %ap = alloca i8*
4717 %ap2 = bitcast i8** %ap to i8*
4718 call void @llvm.va_start(i8* %ap2)
4719
4720 ; Read a single integer argument
4721 %tmp = va_arg i8** %ap, i32
4722
4723 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4724 %aq = alloca i8*
4725 %aq2 = bitcast i8** %aq to i8*
4726 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4727 call void @llvm.va_end(i8* %aq2)
4728
4729 ; Stop processing of arguments.
4730 call void @llvm.va_end(i8* %ap2)
4731 ret i32 %tmp
4732}
4733
4734declare void @llvm.va_start(i8*)
4735declare void @llvm.va_copy(i8*, i8*)
4736declare void @llvm.va_end(i8*)
4737</pre>
4738</div>
4739
4740</div>
4741
4742<!-- _______________________________________________________________________ -->
4743<div class="doc_subsubsection">
4744 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4745</div>
4746
4747
4748<div class="doc_text">
4749<h5>Syntax:</h5>
4750<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4751<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4752<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4753<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4754href="#i_va_arg">va_arg</a></tt>.</p>
4755
4756<h5>Arguments:</h5>
4757
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4758<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]4759
4760<h5>Semantics:</h5>
4761
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4762<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]4763macro available in C. In a target-dependent way, it initializes the
4764<tt>va_list</tt> element to which the argument points, so that the next call to
4765<tt>va_arg</tt> will produce the first variable argument passed to the function.
4766Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4767last argument of the function as the compiler can figure that out.</p>
4768
4769</div>
4770
4771<!-- _______________________________________________________________________ -->
4772<div class="doc_subsubsection">
4773 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4774</div>
4775
4776<div class="doc_text">
4777<h5>Syntax:</h5>
4778<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4779<h5>Overview:</h5>
4780
4781<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4782which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4783or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4784
4785<h5>Arguments:</h5>
4786
4787<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4788
4789<h5>Semantics:</h5>
4790
4791<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4792macro available in C. In a target-dependent way, it destroys the
4793<tt>va_list</tt> element to which the argument points. Calls to <a
4794href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4795<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4796<tt>llvm.va_end</tt>.</p>
4797
4798</div>
4799
4800<!-- _______________________________________________________________________ -->
4801<div class="doc_subsubsection">
4802 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4803</div>
4804
4805<div class="doc_text">
4806
4807<h5>Syntax:</h5>
4808
4809<pre>
4810 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4811</pre>
4812
4813<h5>Overview:</h5>
4814
4815<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4816from the source argument list to the destination argument list.</p>
4817
4818<h5>Arguments:</h5>
4819
4820<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4821The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4822
4823
4824<h5>Semantics:</h5>
4825
4826<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4827macro available in C. In a target-dependent way, it copies the source
4828<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4829intrinsic is necessary because the <tt><a href="#int_va_start">
4830llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4831example, memory allocation.</p>
4832
4833</div>
4834
4835<!-- ======================================================================= -->
4836<div class="doc_subsection">
4837 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4838</div>
4839
4840<div class="doc_text">
4841
4842<p>
4843LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4844Collection</a> (GC) requires the implementation and generation of these
4845intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4846These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4847stack</a>, as well as garbage collector implementations that require <a
4848href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4849Front-ends for type-safe garbage collected languages should generate these
4850intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4851href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4852</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4853
4854<p>The garbage collection intrinsics only operate on objects in the generic
4855 address space (address space zero).</p>
4856
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4857</div>
4858
4859<!-- _______________________________________________________________________ -->
4860<div class="doc_subsubsection">
4861 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4862</div>
4863
4864<div class="doc_text">
4865
4866<h5>Syntax:</h5>
4867
4868<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4869 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4870</pre>
4871
4872<h5>Overview:</h5>
4873
4874<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4875the code generator, and allows some metadata to be associated with it.</p>
4876
4877<h5>Arguments:</h5>
4878
4879<p>The first argument specifies the address of a stack object that contains the
4880root pointer. The second pointer (which must be either a constant or a global
4881value address) contains the meta-data to be associated with the root.</p>
4882
4883<h5>Semantics:</h5>
4884
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4885<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]4886location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4887the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4888intrinsic may only be used in a function which <a href="#gc">specifies a GC
4889algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4890
4891</div>
4892
4893
4894<!-- _______________________________________________________________________ -->
4895<div class="doc_subsubsection">
4896 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4897</div>
4898
4899<div class="doc_text">
4900
4901<h5>Syntax:</h5>
4902
4903<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4904 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4905</pre>
4906
4907<h5>Overview:</h5>
4908
4909<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4910locations, allowing garbage collector implementations that require read
4911barriers.</p>
4912
4913<h5>Arguments:</h5>
4914
4915<p>The second argument is the address to read from, which should be an address
4916allocated from the garbage collector. The first object is a pointer to the
4917start of the referenced object, if needed by the language runtime (otherwise
4918null).</p>
4919
4920<h5>Semantics:</h5>
4921
4922<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4923instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4924garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4925may only be used in a function which <a href="#gc">specifies a GC
4926algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4927
4928</div>
4929
4930
4931<!-- _______________________________________________________________________ -->
4932<div class="doc_subsubsection">
4933 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4934</div>
4935
4936<div class="doc_text">
4937
4938<h5>Syntax:</h5>
4939
4940<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4941 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4942</pre>
4943
4944<h5>Overview:</h5>
4945
4946<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4947locations, allowing garbage collector implementations that require write
4948barriers (such as generational or reference counting collectors).</p>
4949
4950<h5>Arguments:</h5>
4951
4952<p>The first argument is the reference to store, the second is the start of the
4953object to store it to, and the third is the address of the field of Obj to
4954store to. If the runtime does not require a pointer to the object, Obj may be
4955null.</p>
4956
4957<h5>Semantics:</h5>
4958
4959<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4960instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4961garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4962may only be used in a function which <a href="#gc">specifies a GC
4963algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4964
4965</div>
4966
4967
4968
4969<!-- ======================================================================= -->
4970<div class="doc_subsection">
4971 <a name="int_codegen">Code Generator Intrinsics</a>
4972</div>
4973
4974<div class="doc_text">
4975<p>
4976These intrinsics are provided by LLVM to expose special features that may only
4977be implemented with code generator support.
4978</p>
4979
4980</div>
4981
4982<!-- _______________________________________________________________________ -->
4983<div class="doc_subsubsection">
4984 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4985</div>
4986
4987<div class="doc_text">
4988
4989<h5>Syntax:</h5>
4990<pre>
4991 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4992</pre>
4993
4994<h5>Overview:</h5>
4995
4996<p>
4997The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4998target-specific value indicating the return address of the current function
4999or one of its callers.
5000</p>
5001
5002<h5>Arguments:</h5>
5003
5004<p>
5005The argument to this intrinsic indicates which function to return the address
5006for. Zero indicates the calling function, one indicates its caller, etc. The
5007argument is <b>required</b> to be a constant integer value.
5008</p>
5009
5010<h5>Semantics:</h5>
5011
5012<p>
5013The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5014the return address of the specified call frame, or zero if it cannot be
5015identified. The value returned by this intrinsic is likely to be incorrect or 0
5016for arguments other than zero, so it should only be used for debugging purposes.
5017</p>
5018
5019<p>
5020Note that calling this intrinsic does not prevent function inlining or other
5021aggressive transformations, so the value returned may not be that of the obvious
5022source-language caller.
5023</p>
5024</div>
5025
5026
5027<!-- _______________________________________________________________________ -->
5028<div class="doc_subsubsection">
5029 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5030</div>
5031
5032<div class="doc_text">
5033
5034<h5>Syntax:</h5>
5035<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5036 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5037</pre>
5038
5039<h5>Overview:</h5>
5040
5041<p>
5042The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5043target-specific frame pointer value for the specified stack frame.
5044</p>
5045
5046<h5>Arguments:</h5>
5047
5048<p>
5049The argument to this intrinsic indicates which function to return the frame
5050pointer for. Zero indicates the calling function, one indicates its caller,
5051etc. The argument is <b>required</b> to be a constant integer value.
5052</p>
5053
5054<h5>Semantics:</h5>
5055
5056<p>
5057The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5058the frame address of the specified call frame, or zero if it cannot be
5059identified. The value returned by this intrinsic is likely to be incorrect or 0
5060for arguments other than zero, so it should only be used for debugging purposes.
5061</p>
5062
5063<p>
5064Note that calling this intrinsic does not prevent function inlining or other
5065aggressive transformations, so the value returned may not be that of the obvious
5066source-language caller.
5067</p>
5068</div>
5069
5070<!-- _______________________________________________________________________ -->
5071<div class="doc_subsubsection">
5072 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5073</div>
5074
5075<div class="doc_text">
5076
5077<h5>Syntax:</h5>
5078<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5079 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5080</pre>
5081
5082<h5>Overview:</h5>
5083
5084<p>
5085The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5086the function stack, for use with <a href="#int_stackrestore">
5087<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5088features like scoped automatic variable sized arrays in C99.
5089</p>
5090
5091<h5>Semantics:</h5>
5092
5093<p>
5094This intrinsic returns a opaque pointer value that can be passed to <a
5095href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5096<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5097<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5098state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5099practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5100that were allocated after the <tt>llvm.stacksave</tt> was executed.
5101</p>
5102
5103</div>
5104
5105<!-- _______________________________________________________________________ -->
5106<div class="doc_subsubsection">
5107 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5108</div>
5109
5110<div class="doc_text">
5111
5112<h5>Syntax:</h5>
5113<pre>
5114 declare void @llvm.stackrestore(i8 * %ptr)
5115</pre>
5116
5117<h5>Overview:</h5>
5118
5119<p>
5120The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5121the function stack to the state it was in when the corresponding <a
5122href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5123useful for implementing language features like scoped automatic variable sized
5124arrays in C99.
5125</p>
5126
5127<h5>Semantics:</h5>
5128
5129<p>
5130See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5131</p>
5132
5133</div>
5134
5135
5136<!-- _______________________________________________________________________ -->
5137<div class="doc_subsubsection">
5138 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5139</div>
5140
5141<div class="doc_text">
5142
5143<h5>Syntax:</h5>
5144<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5145 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]5146</pre>
5147
5148<h5>Overview:</h5>
5149
5150
5151<p>
5152The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5153a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5154no
5155effect on the behavior of the program but can change its performance
5156characteristics.
5157</p>
5158
5159<h5>Arguments:</h5>
5160
5161<p>
5162<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5163determining if the fetch should be for a read (0) or write (1), and
5164<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5165locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5166<tt>locality</tt> arguments must be constant integers.
5167</p>
5168
5169<h5>Semantics:</h5>
5170
5171<p>
5172This intrinsic does not modify the behavior of the program. In particular,
5173prefetches cannot trap and do not produce a value. On targets that support this
5174intrinsic, the prefetch can provide hints to the processor cache for better
5175performance.
5176</p>
5177
5178</div>
5179
5180<!-- _______________________________________________________________________ -->
5181<div class="doc_subsubsection">
5182 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5183</div>
5184
5185<div class="doc_text">
5186
5187<h5>Syntax:</h5>
5188<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5189 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5190</pre>
5191
5192<h5>Overview:</h5>
5193
5194
5195<p>
5196The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5197(PC) in a region of
5198code to simulators and other tools. The method is target specific, but it is
5199expected that the marker will use exported symbols to transmit the PC of the
5200marker.
5201The marker makes no guarantees that it will remain with any specific instruction
5202after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5203optimizations. The intended use is to be inserted after optimizations to allow
5204correlations of simulation runs.
5205</p>
5206
5207<h5>Arguments:</h5>
5208
5209<p>
5210<tt>id</tt> is a numerical id identifying the marker.
5211</p>
5212
5213<h5>Semantics:</h5>
5214
5215<p>
5216This intrinsic does not modify the behavior of the program. Backends that do not
5217support this intrinisic may ignore it.
5218</p>
5219
5220</div>
5221
5222<!-- _______________________________________________________________________ -->
5223<div class="doc_subsubsection">
5224 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5225</div>
5226
5227<div class="doc_text">
5228
5229<h5>Syntax:</h5>
5230<pre>
5231 declare i64 @llvm.readcyclecounter( )
5232</pre>
5233
5234<h5>Overview:</h5>
5235
5236
5237<p>
5238The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5239counter register (or similar low latency, high accuracy clocks) on those targets
5240that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5241As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5242should only be used for small timings.
5243</p>
5244
5245<h5>Semantics:</h5>
5246
5247<p>
5248When directly supported, reading the cycle counter should not modify any memory.
5249Implementations are allowed to either return a application specific value or a
5250system wide value. On backends without support, this is lowered to a constant 0.
5251</p>
5252
5253</div>
5254
5255<!-- ======================================================================= -->
5256<div class="doc_subsection">
5257 <a name="int_libc">Standard C Library Intrinsics</a>
5258</div>
5259
5260<div class="doc_text">
5261<p>
5262LLVM provides intrinsics for a few important standard C library functions.
5263These intrinsics allow source-language front-ends to pass information about the
5264alignment of the pointer arguments to the code generator, providing opportunity
5265for more efficient code generation.
5266</p>
5267
5268</div>
5269
5270<!-- _______________________________________________________________________ -->
5271<div class="doc_subsubsection">
5272 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5273</div>
5274
5275<div class="doc_text">
5276
5277<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5278<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5279width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5280<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5281 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5282 i8 &lt;len&gt;, i32 &lt;align&gt;)
5283 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5284 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5286 i32 &lt;len&gt;, i32 &lt;align&gt;)
5287 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5288 i64 &lt;len&gt;, i32 &lt;align&gt;)
5289</pre>
5290
5291<h5>Overview:</h5>
5292
5293<p>
5294The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5295location to the destination location.
5296</p>
5297
5298<p>
5299Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5300intrinsics do not return a value, and takes an extra alignment argument.
5301</p>
5302
5303<h5>Arguments:</h5>
5304
5305<p>
5306The first argument is a pointer to the destination, the second is a pointer to
5307the source. The third argument is an integer argument
5308specifying the number of bytes to copy, and the fourth argument is the alignment
5309of the source and destination locations.
5310</p>
5311
5312<p>
5313If the call to this intrinisic has an alignment value that is not 0 or 1, then
5314the caller guarantees that both the source and destination pointers are aligned
5315to that boundary.
5316</p>
5317
5318<h5>Semantics:</h5>
5319
5320<p>
5321The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5322location to the destination location, which are not allowed to overlap. It
5323copies "len" bytes of memory over. If the argument is known to be aligned to
5324some boundary, this can be specified as the fourth argument, otherwise it should
5325be set to 0 or 1.
5326</p>
5327</div>
5328
5329
5330<!-- _______________________________________________________________________ -->
5331<div class="doc_subsubsection">
5332 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5333</div>
5334
5335<div class="doc_text">
5336
5337<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5338<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5339width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5340<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5341 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5342 i8 &lt;len&gt;, i32 &lt;align&gt;)
5343 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5344 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5345 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5346 i32 &lt;len&gt;, i32 &lt;align&gt;)
5347 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5348 i64 &lt;len&gt;, i32 &lt;align&gt;)
5349</pre>
5350
5351<h5>Overview:</h5>
5352
5353<p>
5354The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5355location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5356'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5357</p>
5358
5359<p>
5360Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5361intrinsics do not return a value, and takes an extra alignment argument.
5362</p>
5363
5364<h5>Arguments:</h5>
5365
5366<p>
5367The first argument is a pointer to the destination, the second is a pointer to
5368the source. The third argument is an integer argument
5369specifying the number of bytes to copy, and the fourth argument is the alignment
5370of the source and destination locations.
5371</p>
5372
5373<p>
5374If the call to this intrinisic has an alignment value that is not 0 or 1, then
5375the caller guarantees that the source and destination pointers are aligned to
5376that boundary.
5377</p>
5378
5379<h5>Semantics:</h5>
5380
5381<p>
5382The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5383location to the destination location, which may overlap. It
5384copies "len" bytes of memory over. If the argument is known to be aligned to
5385some boundary, this can be specified as the fourth argument, otherwise it should
5386be set to 0 or 1.
5387</p>
5388</div>
5389
5390
5391<!-- _______________________________________________________________________ -->
5392<div class="doc_subsubsection">
5393 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5394</div>
5395
5396<div class="doc_text">
5397
5398<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5399<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5400width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5401<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5402 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5403 i8 &lt;len&gt;, i32 &lt;align&gt;)
5404 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5405 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5406 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5407 i32 &lt;len&gt;, i32 &lt;align&gt;)
5408 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5409 i64 &lt;len&gt;, i32 &lt;align&gt;)
5410</pre>
5411
5412<h5>Overview:</h5>
5413
5414<p>
5415The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5416byte value.
5417</p>
5418
5419<p>
5420Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5421does not return a value, and takes an extra alignment argument.
5422</p>
5423
5424<h5>Arguments:</h5>
5425
5426<p>
5427The first argument is a pointer to the destination to fill, the second is the
5428byte value to fill it with, the third argument is an integer
5429argument specifying the number of bytes to fill, and the fourth argument is the
5430known alignment of destination location.
5431</p>
5432
5433<p>
5434If the call to this intrinisic has an alignment value that is not 0 or 1, then
5435the caller guarantees that the destination pointer is aligned to that boundary.
5436</p>
5437
5438<h5>Semantics:</h5>
5439
5440<p>
5441The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5442the
5443destination location. If the argument is known to be aligned to some boundary,
5444this can be specified as the fourth argument, otherwise it should be set to 0 or
54451.
5446</p>
5447</div>
5448
5449
5450<!-- _______________________________________________________________________ -->
5451<div class="doc_subsubsection">
5452 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5453</div>
5454
5455<div class="doc_text">
5456
5457<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5458<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]5459floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5460types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5462 declare float @llvm.sqrt.f32(float %Val)
5463 declare double @llvm.sqrt.f64(double %Val)
5464 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5465 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5466 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5467</pre>
5468
5469<h5>Overview:</h5>
5470
5471<p>
5472The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5473returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5474<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5475negative numbers other than -0.0 (which allows for better optimization, because
5476there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5477defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5478</p>
5479
5480<h5>Arguments:</h5>
5481
5482<p>
5483The argument and return value are floating point numbers of the same type.
5484</p>
5485
5486<h5>Semantics:</h5>
5487
5488<p>
5489This function returns the sqrt of the specified operand if it is a nonnegative
5490floating point number.
5491</p>
5492</div>
5493
5494<!-- _______________________________________________________________________ -->
5495<div class="doc_subsubsection">
5496 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5497</div>
5498
5499<div class="doc_text">
5500
5501<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5502<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]5503floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5504types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5505<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5506 declare float @llvm.powi.f32(float %Val, i32 %power)
5507 declare double @llvm.powi.f64(double %Val, i32 %power)
5508 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5509 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5510 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5511</pre>
5512
5513<h5>Overview:</h5>
5514
5515<p>
5516The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5517specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5518multiplications is not defined. When a vector of floating point type is
5519used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5520</p>
5521
5522<h5>Arguments:</h5>
5523
5524<p>
5525The second argument is an integer power, and the first is a value to raise to
5526that power.
5527</p>
5528
5529<h5>Semantics:</h5>
5530
5531<p>
5532This function returns the first value raised to the second power with an
5533unspecified sequence of rounding operations.</p>
5534</div>
5535
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5536<!-- _______________________________________________________________________ -->
5537<div class="doc_subsubsection">
5538 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5539</div>
5540
5541<div class="doc_text">
5542
5543<h5>Syntax:</h5>
5544<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5545floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5546types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5547<pre>
5548 declare float @llvm.sin.f32(float %Val)
5549 declare double @llvm.sin.f64(double %Val)
5550 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5551 declare fp128 @llvm.sin.f128(fp128 %Val)
5552 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5553</pre>
5554
5555<h5>Overview:</h5>
5556
5557<p>
5558The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5559</p>
5560
5561<h5>Arguments:</h5>
5562
5563<p>
5564The argument and return value are floating point numbers of the same type.
5565</p>
5566
5567<h5>Semantics:</h5>
5568
5569<p>
5570This function returns the sine of the specified operand, returning the
5571same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5572conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5573</div>
5574
5575<!-- _______________________________________________________________________ -->
5576<div class="doc_subsubsection">
5577 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5578</div>
5579
5580<div class="doc_text">
5581
5582<h5>Syntax:</h5>
5583<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5584floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5585types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5586<pre>
5587 declare float @llvm.cos.f32(float %Val)
5588 declare double @llvm.cos.f64(double %Val)
5589 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5590 declare fp128 @llvm.cos.f128(fp128 %Val)
5591 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5592</pre>
5593
5594<h5>Overview:</h5>
5595
5596<p>
5597The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5598</p>
5599
5600<h5>Arguments:</h5>
5601
5602<p>
5603The argument and return value are floating point numbers of the same type.
5604</p>
5605
5606<h5>Semantics:</h5>
5607
5608<p>
5609This function returns the cosine of the specified operand, returning the
5610same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5611conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5612</div>
5613
5614<!-- _______________________________________________________________________ -->
5615<div class="doc_subsubsection">
5616 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5617</div>
5618
5619<div class="doc_text">
5620
5621<h5>Syntax:</h5>
5622<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5623floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5624types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5625<pre>
5626 declare float @llvm.pow.f32(float %Val, float %Power)
5627 declare double @llvm.pow.f64(double %Val, double %Power)
5628 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5629 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5630 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5631</pre>
5632
5633<h5>Overview:</h5>
5634
5635<p>
5636The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5637specified (positive or negative) power.
5638</p>
5639
5640<h5>Arguments:</h5>
5641
5642<p>
5643The second argument is a floating point power, and the first is a value to
5644raise to that power.
5645</p>
5646
5647<h5>Semantics:</h5>
5648
5649<p>
5650This function returns the first value raised to the second power,
5651returning the
5652same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5653conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5654</div>
5655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5656
5657<!-- ======================================================================= -->
5658<div class="doc_subsection">
5659 <a name="int_manip">Bit Manipulation Intrinsics</a>
5660</div>
5661
5662<div class="doc_text">
5663<p>
5664LLVM provides intrinsics for a few important bit manipulation operations.
5665These allow efficient code generation for some algorithms.
5666</p>
5667
5668</div>
5669
5670<!-- _______________________________________________________________________ -->
5671<div class="doc_subsubsection">
5672 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5673</div>
5674
5675<div class="doc_text">
5676
5677<h5>Syntax:</h5>
5678<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5679type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5680<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5681 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5682 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5683 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5684</pre>
5685
5686<h5>Overview:</h5>
5687
5688<p>
5689The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5690values with an even number of bytes (positive multiple of 16 bits). These are
5691useful for performing operations on data that is not in the target's native
5692byte order.
5693</p>
5694
5695<h5>Semantics:</h5>
5696
5697<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5698The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5699and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5700intrinsic returns an i32 value that has the four bytes of the input i32
5701swapped, 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]5702i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5703<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5704additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5705</p>
5706
5707</div>
5708
5709<!-- _______________________________________________________________________ -->
5710<div class="doc_subsubsection">
5711 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5712</div>
5713
5714<div class="doc_text">
5715
5716<h5>Syntax:</h5>
5717<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]5718width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5719<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5720 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5721 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5722 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5723 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5724 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725</pre>
5726
5727<h5>Overview:</h5>
5728
5729<p>
5730The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5731value.
5732</p>
5733
5734<h5>Arguments:</h5>
5735
5736<p>
5737The only argument is the value to be counted. The argument may be of any
5738integer type. The return type must match the argument type.
5739</p>
5740
5741<h5>Semantics:</h5>
5742
5743<p>
5744The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5745</p>
5746</div>
5747
5748<!-- _______________________________________________________________________ -->
5749<div class="doc_subsubsection">
5750 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5751</div>
5752
5753<div class="doc_text">
5754
5755<h5>Syntax:</h5>
5756<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]5757integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5758<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5759 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5760 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5761 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5762 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5763 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5764</pre>
5765
5766<h5>Overview:</h5>
5767
5768<p>
5769The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5770leading zeros in a variable.
5771</p>
5772
5773<h5>Arguments:</h5>
5774
5775<p>
5776The only argument is the value to be counted. The argument may be of any
5777integer type. The return type must match the argument type.
5778</p>
5779
5780<h5>Semantics:</h5>
5781
5782<p>
5783The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5784in a variable. If the src == 0 then the result is the size in bits of the type
5785of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5786</p>
5787</div>
5788
5789
5790
5791<!-- _______________________________________________________________________ -->
5792<div class="doc_subsubsection">
5793 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5794</div>
5795
5796<div class="doc_text">
5797
5798<h5>Syntax:</h5>
5799<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]5800integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5801<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5802 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5803 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5804 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5805 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5806 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5807</pre>
5808
5809<h5>Overview:</h5>
5810
5811<p>
5812The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5813trailing zeros.
5814</p>
5815
5816<h5>Arguments:</h5>
5817
5818<p>
5819The only argument is the value to be counted. The argument may be of any
5820integer type. The return type must match the argument type.
5821</p>
5822
5823<h5>Semantics:</h5>
5824
5825<p>
5826The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5827in a variable. If the src == 0 then the result is the size in bits of the type
5828of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5829</p>
5830</div>
5831
5832<!-- _______________________________________________________________________ -->
5833<div class="doc_subsubsection">
5834 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5835</div>
5836
5837<div class="doc_text">
5838
5839<h5>Syntax:</h5>
5840<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5841on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5842<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5843 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5844 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5845</pre>
5846
5847<h5>Overview:</h5>
5848<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5849range of bits from an integer value and returns them in the same bit width as
5850the original value.</p>
5851
5852<h5>Arguments:</h5>
5853<p>The first argument, <tt>%val</tt> and the result may be integer types of
5854any bit width but they must have the same bit width. The second and third
5855arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5856
5857<h5>Semantics:</h5>
5858<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5859of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5860<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5861operates in forward mode.</p>
5862<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5863right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5864only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5865<ol>
5866 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5867 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5868 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5869 to determine the number of bits to retain.</li>
5870 <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]5871 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5872</ol>
5873<p>In reverse mode, a similar computation is made except that the bits are
5874returned in the reverse order. So, for example, if <tt>X</tt> has the value
5875<tt>i16 0x0ACF (101011001111)</tt> and we apply
5876<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5877<tt>i16 0x0026 (000000100110)</tt>.</p>
5878</div>
5879
5880<div class="doc_subsubsection">
5881 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5882</div>
5883
5884<div class="doc_text">
5885
5886<h5>Syntax:</h5>
5887<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5888on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5889<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5890 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5891 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]5892</pre>
5893
5894<h5>Overview:</h5>
5895<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5896of bits in an integer value with another integer value. It returns the integer
5897with the replaced bits.</p>
5898
5899<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5900<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5901any 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]5902whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5903integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5904type since they specify only a bit index.</p>
5905
5906<h5>Semantics:</h5>
5907<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5908of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5909<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5910operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5911
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5912<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5913truncating it down to the size of the replacement area or zero extending it
5914up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5915
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5916<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5917are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5918in <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]5919to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5921<p>In reverse mode, a similar computation is made except that the bits are
5922reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5923<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]5924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5925<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5927<pre>
5928 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5929 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5930 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5931 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5932 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5933</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5934
5935</div>
5936
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5937<!-- ======================================================================= -->
5938<div class="doc_subsection">
5939 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5940</div>
5941
5942<div class="doc_text">
5943<p>
5944LLVM provides intrinsics for some arithmetic with overflow operations.
5945</p>
5946
5947</div>
5948
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5949<!-- _______________________________________________________________________ -->
5950<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5951 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5952</div>
5953
5954<div class="doc_text">
5955
5956<h5>Syntax:</h5>
5957
5958<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]5959on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5960
5961<pre>
5962 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5963 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5964 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5965</pre>
5966
5967<h5>Overview:</h5>
5968
5969<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5970a signed addition of the two arguments, and indicate whether an overflow
5971occurred during the signed summation.</p>
5972
5973<h5>Arguments:</h5>
5974
5975<p>The arguments (%a and %b) and the first element of the result structure may
5976be of integer types of any bit width, but they must have the same bit width. The
5977second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5978and <tt>%b</tt> are the two values that will undergo signed addition.</p>
5979
5980<h5>Semantics:</h5>
5981
5982<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5983a signed addition of the two variables. They return a structure &mdash; the
5984first element of which is the signed summation, and the second element of which
5985is a bit specifying if the signed summation resulted in an overflow.</p>
5986
5987<h5>Examples:</h5>
5988<pre>
5989 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5990 %sum = extractvalue {i32, i1} %res, 0
5991 %obit = extractvalue {i32, i1} %res, 1
5992 br i1 %obit, label %overflow, label %normal
5993</pre>
5994
5995</div>
5996
5997<!-- _______________________________________________________________________ -->
5998<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5999 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6000</div>
6001
6002<div class="doc_text">
6003
6004<h5>Syntax:</h5>
6005
6006<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]6007on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6008
6009<pre>
6010 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6011 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6012 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6013</pre>
6014
6015<h5>Overview:</h5>
6016
6017<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6018an unsigned addition of the two arguments, and indicate whether a carry occurred
6019during the unsigned summation.</p>
6020
6021<h5>Arguments:</h5>
6022
6023<p>The arguments (%a and %b) and the first element of the result structure may
6024be of integer types of any bit width, but they must have the same bit width. The
6025second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6026and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6027
6028<h5>Semantics:</h5>
6029
6030<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6031an unsigned addition of the two arguments. They return a structure &mdash; the
6032first element of which is the sum, and the second element of which is a bit
6033specifying if the unsigned summation resulted in a carry.</p>
6034
6035<h5>Examples:</h5>
6036<pre>
6037 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6038 %sum = extractvalue {i32, i1} %res, 0
6039 %obit = extractvalue {i32, i1} %res, 1
6040 br i1 %obit, label %carry, label %normal
6041</pre>
6042
6043</div>
6044
6045<!-- _______________________________________________________________________ -->
6046<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6047 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6048</div>
6049
6050<div class="doc_text">
6051
6052<h5>Syntax:</h5>
6053
6054<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]6055on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6056
6057<pre>
6058 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6059 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6060 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6061</pre>
6062
6063<h5>Overview:</h5>
6064
6065<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6066a signed subtraction of the two arguments, and indicate whether an overflow
6067occurred during the signed subtraction.</p>
6068
6069<h5>Arguments:</h5>
6070
6071<p>The arguments (%a and %b) and the first element of the result structure may
6072be of integer types of any bit width, but they must have the same bit width. The
6073second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6074and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6075
6076<h5>Semantics:</h5>
6077
6078<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6079a signed subtraction of the two arguments. They return a structure &mdash; the
6080first element of which is the subtraction, and the second element of which is a bit
6081specifying if the signed subtraction resulted in an overflow.</p>
6082
6083<h5>Examples:</h5>
6084<pre>
6085 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6086 %sum = extractvalue {i32, i1} %res, 0
6087 %obit = extractvalue {i32, i1} %res, 1
6088 br i1 %obit, label %overflow, label %normal
6089</pre>
6090
6091</div>
6092
6093<!-- _______________________________________________________________________ -->
6094<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6095 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6096</div>
6097
6098<div class="doc_text">
6099
6100<h5>Syntax:</h5>
6101
6102<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]6103on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6104
6105<pre>
6106 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6107 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6108 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6109</pre>
6110
6111<h5>Overview:</h5>
6112
6113<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6114an unsigned subtraction of the two arguments, and indicate whether an overflow
6115occurred during the unsigned subtraction.</p>
6116
6117<h5>Arguments:</h5>
6118
6119<p>The arguments (%a and %b) and the first element of the result structure may
6120be of integer types of any bit width, but they must have the same bit width. The
6121second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6122and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6123
6124<h5>Semantics:</h5>
6125
6126<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6127an unsigned subtraction of the two arguments. They return a structure &mdash; the
6128first element of which is the subtraction, and the second element of which is a bit
6129specifying if the unsigned subtraction resulted in an overflow.</p>
6130
6131<h5>Examples:</h5>
6132<pre>
6133 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6134 %sum = extractvalue {i32, i1} %res, 0
6135 %obit = extractvalue {i32, i1} %res, 1
6136 br i1 %obit, label %overflow, label %normal
6137</pre>
6138
6139</div>
6140
6141<!-- _______________________________________________________________________ -->
6142<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6143 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6144</div>
6145
6146<div class="doc_text">
6147
6148<h5>Syntax:</h5>
6149
6150<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]6151on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6152
6153<pre>
6154 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6155 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6156 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6157</pre>
6158
6159<h5>Overview:</h5>
6160
6161<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6162a signed multiplication of the two arguments, and indicate whether an overflow
6163occurred during the signed multiplication.</p>
6164
6165<h5>Arguments:</h5>
6166
6167<p>The arguments (%a and %b) and the first element of the result structure may
6168be of integer types of any bit width, but they must have the same bit width. The
6169second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6170and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6171
6172<h5>Semantics:</h5>
6173
6174<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6175a signed multiplication of the two arguments. They return a structure &mdash;
6176the first element of which is the multiplication, and the second element of
6177which is a bit specifying if the signed multiplication resulted in an
6178overflow.</p>
6179
6180<h5>Examples:</h5>
6181<pre>
6182 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6183 %sum = extractvalue {i32, i1} %res, 0
6184 %obit = extractvalue {i32, i1} %res, 1
6185 br i1 %obit, label %overflow, label %normal
6186</pre>
6187
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6188</div>
6189
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6190<!-- _______________________________________________________________________ -->
6191<div class="doc_subsubsection">
6192 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6193</div>
6194
6195<div class="doc_text">
6196
6197<h5>Syntax:</h5>
6198
6199<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6200on any integer bit width.</p>
6201
6202<pre>
6203 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6204 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6205 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6206</pre>
6207
6208<h5>Overview:</h5>
6209
6210<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6211actively being fixed, but it should not currently be used!</i></p>
6212
6213<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6214a unsigned multiplication of the two arguments, and indicate whether an overflow
6215occurred during the unsigned multiplication.</p>
6216
6217<h5>Arguments:</h5>
6218
6219<p>The arguments (%a and %b) and the first element of the result structure may
6220be of integer types of any bit width, but they must have the same bit width. The
6221second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6222and <tt>%b</tt> are the two values that will undergo unsigned
6223multiplication.</p>
6224
6225<h5>Semantics:</h5>
6226
6227<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6228an unsigned multiplication of the two arguments. They return a structure &mdash;
6229the first element of which is the multiplication, and the second element of
6230which is a bit specifying if the unsigned multiplication resulted in an
6231overflow.</p>
6232
6233<h5>Examples:</h5>
6234<pre>
6235 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6236 %sum = extractvalue {i32, i1} %res, 0
6237 %obit = extractvalue {i32, i1} %res, 1
6238 br i1 %obit, label %overflow, label %normal
6239</pre>
6240
6241</div>
6242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6243<!-- ======================================================================= -->
6244<div class="doc_subsection">
6245 <a name="int_debugger">Debugger Intrinsics</a>
6246</div>
6247
6248<div class="doc_text">
6249<p>
6250The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6251are described in the <a
6252href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6253Debugging</a> document.
6254</p>
6255</div>
6256
6257
6258<!-- ======================================================================= -->
6259<div class="doc_subsection">
6260 <a name="int_eh">Exception Handling Intrinsics</a>
6261</div>
6262
6263<div class="doc_text">
6264<p> The LLVM exception handling intrinsics (which all start with
6265<tt>llvm.eh.</tt> prefix), are described in the <a
6266href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6267Handling</a> document. </p>
6268</div>
6269
6270<!-- ======================================================================= -->
6271<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6272 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6273</div>
6274
6275<div class="doc_text">
6276<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6277 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6278 the <tt>nest</tt> attribute, from a function. The result is a callable
6279 function pointer lacking the nest parameter - the caller does not need
6280 to provide a value for it. Instead, the value to use is stored in
6281 advance in a "trampoline", a block of memory usually allocated
6282 on the stack, which also contains code to splice the nest value into the
6283 argument list. This is used to implement the GCC nested function address
6284 extension.
6285</p>
6286<p>
6287 For example, if the function is
6288 <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]6289 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]6290<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6291 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6292 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6293 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6294 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6295</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6296 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6297 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6298</div>
6299
6300<!-- _______________________________________________________________________ -->
6301<div class="doc_subsubsection">
6302 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6303</div>
6304<div class="doc_text">
6305<h5>Syntax:</h5>
6306<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6307declare 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]6308</pre>
6309<h5>Overview:</h5>
6310<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6311 This fills the memory pointed to by <tt>tramp</tt> with code
6312 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6313</p>
6314<h5>Arguments:</h5>
6315<p>
6316 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6317 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6318 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6319 intrinsic. Note that the size and the alignment are target-specific - LLVM
6320 currently provides no portable way of determining them, so a front-end that
6321 generates this intrinsic needs to have some target-specific knowledge.
6322 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]6323</p>
6324<h5>Semantics:</h5>
6325<p>
6326 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6327 dependent code, turning it into a function. A pointer to this function is
6328 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6329 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6330 before being called. The new function's signature is the same as that of
6331 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6332 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6333 of pointer type. Calling the new function is equivalent to calling
6334 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6335 missing <tt>nest</tt> argument. If, after calling
6336 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6337 modified, then the effect of any later call to the returned function pointer is
6338 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6339</p>
6340</div>
6341
6342<!-- ======================================================================= -->
6343<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6344 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6345</div>
6346
6347<div class="doc_text">
6348<p>
6349 These intrinsic functions expand the "universal IR" of LLVM to represent
6350 hardware constructs for atomic operations and memory synchronization. This
6351 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6352 is aimed at a low enough level to allow any programming models or APIs
6353 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6354 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6355 hardware behavior. Just as hardware provides a "universal IR" for source
6356 languages, it also provides a starting point for developing a "universal"
6357 atomic operation and synchronization IR.
6358</p>
6359<p>
6360 These do <em>not</em> form an API such as high-level threading libraries,
6361 software transaction memory systems, atomic primitives, and intrinsic
6362 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6363 application libraries. The hardware interface provided by LLVM should allow
6364 a clean implementation of all of these APIs and parallel programming models.
6365 No one model or paradigm should be selected above others unless the hardware
6366 itself ubiquitously does so.
6367
6368</p>
6369</div>
6370
6371<!-- _______________________________________________________________________ -->
6372<div class="doc_subsubsection">
6373 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6374</div>
6375<div class="doc_text">
6376<h5>Syntax:</h5>
6377<pre>
6378declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6379i1 &lt;device&gt; )
6380
6381</pre>
6382<h5>Overview:</h5>
6383<p>
6384 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6385 specific pairs of memory access types.
6386</p>
6387<h5>Arguments:</h5>
6388<p>
6389 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6390 The first four arguments enables a specific barrier as listed below. The fith
6391 argument specifies that the barrier applies to io or device or uncached memory.
6392
6393</p>
6394 <ul>
6395 <li><tt>ll</tt>: load-load barrier</li>
6396 <li><tt>ls</tt>: load-store barrier</li>
6397 <li><tt>sl</tt>: store-load barrier</li>
6398 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6399 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6400 </ul>
6401<h5>Semantics:</h5>
6402<p>
6403 This intrinsic causes the system to enforce some ordering constraints upon
6404 the loads and stores of the program. This barrier does not indicate
6405 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6406 which they occur. For any of the specified pairs of load and store operations
6407 (f.ex. load-load, or store-load), all of the first operations preceding the
6408 barrier will complete before any of the second operations succeeding the
6409 barrier begin. Specifically the semantics for each pairing is as follows:
6410</p>
6411 <ul>
6412 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6413 after the barrier begins.</li>
6414
6415 <li><tt>ls</tt>: All loads before the barrier must complete before any
6416 store after the barrier begins.</li>
6417 <li><tt>ss</tt>: All stores before the barrier must complete before any
6418 store after the barrier begins.</li>
6419 <li><tt>sl</tt>: All stores before the barrier must complete before any
6420 load after the barrier begins.</li>
6421 </ul>
6422<p>
6423 These semantics are applied with a logical "and" behavior when more than one
6424 is enabled in a single memory barrier intrinsic.
6425</p>
6426<p>
6427 Backends may implement stronger barriers than those requested when they do not
6428 support as fine grained a barrier as requested. Some architectures do not
6429 need all types of barriers and on such architectures, these become noops.
6430</p>
6431<h5>Example:</h5>
6432<pre>
6433%ptr = malloc i32
6434 store i32 4, %ptr
6435
6436%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6437 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6438 <i>; guarantee the above finishes</i>
6439 store i32 8, %ptr <i>; before this begins</i>
6440</pre>
6441</div>
6442
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6443<!-- _______________________________________________________________________ -->
6444<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6445 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6446</div>
6447<div class="doc_text">
6448<h5>Syntax:</h5>
6449<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6450 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6451 any integer bit width and for different address spaces. Not all targets
6452 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6453
6454<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6455declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6456declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6457declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6458declare 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]6459
6460</pre>
6461<h5>Overview:</h5>
6462<p>
6463 This loads a value in memory and compares it to a given value. If they are
6464 equal, it stores a new value into the memory.
6465</p>
6466<h5>Arguments:</h5>
6467<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6468 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6469 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6470 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6471 this integer type. While any bit width integer may be used, targets may only
6472 lower representations they support in hardware.
6473
6474</p>
6475<h5>Semantics:</h5>
6476<p>
6477 This entire intrinsic must be executed atomically. It first loads the value
6478 in memory pointed to by <tt>ptr</tt> and compares it with the value
6479 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6480 loaded value is yielded in all cases. This provides the equivalent of an
6481 atomic compare-and-swap operation within the SSA framework.
6482</p>
6483<h5>Examples:</h5>
6484
6485<pre>
6486%ptr = malloc i32
6487 store i32 4, %ptr
6488
6489%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6490%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6491 <i>; yields {i32}:result1 = 4</i>
6492%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6493%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6494
6495%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6496%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6497 <i>; yields {i32}:result2 = 8</i>
6498%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6499
6500%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6501</pre>
6502</div>
6503
6504<!-- _______________________________________________________________________ -->
6505<div class="doc_subsubsection">
6506 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6507</div>
6508<div class="doc_text">
6509<h5>Syntax:</h5>
6510
6511<p>
6512 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6513 integer bit width. Not all targets support all bit widths however.</p>
6514<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6515declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6516declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6517declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6518declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6519
6520</pre>
6521<h5>Overview:</h5>
6522<p>
6523 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6524 the value from memory. It then stores the value in <tt>val</tt> in the memory
6525 at <tt>ptr</tt>.
6526</p>
6527<h5>Arguments:</h5>
6528
6529<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6530 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6531 <tt>val</tt> argument and the result must be integers of the same bit width.
6532 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6533 integer type. The targets may only lower integer representations they
6534 support.
6535</p>
6536<h5>Semantics:</h5>
6537<p>
6538 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6539 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6540 equivalent of an atomic swap operation within the SSA framework.
6541
6542</p>
6543<h5>Examples:</h5>
6544<pre>
6545%ptr = malloc i32
6546 store i32 4, %ptr
6547
6548%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6549%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6550 <i>; yields {i32}:result1 = 4</i>
6551%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6552%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6553
6554%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6555%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6556 <i>; yields {i32}:result2 = 8</i>
6557
6558%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6559%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6560</pre>
6561</div>
6562
6563<!-- _______________________________________________________________________ -->
6564<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6565 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6566
6567</div>
6568<div class="doc_text">
6569<h5>Syntax:</h5>
6570<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6571 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]6572 integer bit width. Not all targets support all bit widths however.</p>
6573<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6574declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6575declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6576declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6577declare 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]6578
6579</pre>
6580<h5>Overview:</h5>
6581<p>
6582 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6583 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6584</p>
6585<h5>Arguments:</h5>
6586<p>
6587
6588 The intrinsic takes two arguments, the first a pointer to an integer value
6589 and the second an integer value. The result is also an integer value. These
6590 integer types can have any bit width, but they must all have the same bit
6591 width. The targets may only lower integer representations they support.
6592</p>
6593<h5>Semantics:</h5>
6594<p>
6595 This intrinsic does a series of operations atomically. It first loads the
6596 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6597 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6598</p>
6599
6600<h5>Examples:</h5>
6601<pre>
6602%ptr = malloc i32
6603 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6604%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6605 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6606%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6607 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6608%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6609 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6610%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6611</pre>
6612</div>
6613
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6614<!-- _______________________________________________________________________ -->
6615<div class="doc_subsubsection">
6616 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6617
6618</div>
6619<div class="doc_text">
6620<h5>Syntax:</h5>
6621<p>
6622 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]6623 any integer bit width and for different address spaces. Not all targets
6624 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6625<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6626declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6627declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6628declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6629declare 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]6630
6631</pre>
6632<h5>Overview:</h5>
6633<p>
6634 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6635 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6636</p>
6637<h5>Arguments:</h5>
6638<p>
6639
6640 The intrinsic takes two arguments, the first a pointer to an integer value
6641 and the second an integer value. The result is also an integer value. These
6642 integer types can have any bit width, but they must all have the same bit
6643 width. The targets may only lower integer representations they support.
6644</p>
6645<h5>Semantics:</h5>
6646<p>
6647 This intrinsic does a series of operations atomically. It first loads the
6648 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6649 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6650</p>
6651
6652<h5>Examples:</h5>
6653<pre>
6654%ptr = malloc i32
6655 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6656%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6657 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6658%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6659 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6660%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6661 <i>; yields {i32}:result3 = 2</i>
6662%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6663</pre>
6664</div>
6665
6666<!-- _______________________________________________________________________ -->
6667<div class="doc_subsubsection">
6668 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6669 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6670 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6671 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6672
6673</div>
6674<div class="doc_text">
6675<h5>Syntax:</h5>
6676<p>
6677 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6678 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6679 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6680 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6681<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6682declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6683declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6684declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6685declare 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]6686
6687</pre>
6688
6689<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6690declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6691declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6692declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6693declare 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]6694
6695</pre>
6696
6697<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6698declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6699declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6700declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6701declare 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]6702
6703</pre>
6704
6705<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6706declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6707declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6708declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6709declare 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]6710
6711</pre>
6712<h5>Overview:</h5>
6713<p>
6714 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6715 the value stored in memory at <tt>ptr</tt>. It yields the original value
6716 at <tt>ptr</tt>.
6717</p>
6718<h5>Arguments:</h5>
6719<p>
6720
6721 These intrinsics take two arguments, the first a pointer to an integer value
6722 and the second an integer value. The result is also an integer value. These
6723 integer types can have any bit width, but they must all have the same bit
6724 width. The targets may only lower integer representations they support.
6725</p>
6726<h5>Semantics:</h5>
6727<p>
6728 These intrinsics does a series of operations atomically. They first load the
6729 value stored at <tt>ptr</tt>. They then do the bitwise operation
6730 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6731 value stored at <tt>ptr</tt>.
6732</p>
6733
6734<h5>Examples:</h5>
6735<pre>
6736%ptr = malloc i32
6737 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6738%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6739 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6740%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6741 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6742%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6743 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6744%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6745 <i>; yields {i32}:result3 = FF</i>
6746%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6747</pre>
6748</div>
6749
6750
6751<!-- _______________________________________________________________________ -->
6752<div class="doc_subsubsection">
6753 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6754 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6755 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6756 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6757
6758</div>
6759<div class="doc_text">
6760<h5>Syntax:</h5>
6761<p>
6762 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6763 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6764 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6765 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6766 support all bit widths however.</p>
6767<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6768declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6769declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6770declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6771declare 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]6772
6773</pre>
6774
6775<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6776declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6777declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6778declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6779declare 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]6780
6781</pre>
6782
6783<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6784declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6785declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6786declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6787declare 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]6788
6789</pre>
6790
6791<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6792declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6793declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6794declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6795declare 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]6796
6797</pre>
6798<h5>Overview:</h5>
6799<p>
6800 These intrinsics takes the signed or unsigned minimum or maximum of
6801 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6802 original value at <tt>ptr</tt>.
6803</p>
6804<h5>Arguments:</h5>
6805<p>
6806
6807 These intrinsics take two arguments, the first a pointer to an integer value
6808 and the second an integer value. The result is also an integer value. These
6809 integer types can have any bit width, but they must all have the same bit
6810 width. The targets may only lower integer representations they support.
6811</p>
6812<h5>Semantics:</h5>
6813<p>
6814 These intrinsics does a series of operations atomically. They first load the
6815 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6816 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6817 the original value stored at <tt>ptr</tt>.
6818</p>
6819
6820<h5>Examples:</h5>
6821<pre>
6822%ptr = malloc i32
6823 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6824%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6826%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6827 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6828%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6829 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6830%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6831 <i>; yields {i32}:result3 = 8</i>
6832%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6833</pre>
6834</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6835
6836<!-- ======================================================================= -->
6837<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6838 <a name="int_general">General Intrinsics</a>
6839</div>
6840
6841<div class="doc_text">
6842<p> This class of intrinsics is designed to be generic and has
6843no specific purpose. </p>
6844</div>
6845
6846<!-- _______________________________________________________________________ -->
6847<div class="doc_subsubsection">
6848 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6849</div>
6850
6851<div class="doc_text">
6852
6853<h5>Syntax:</h5>
6854<pre>
6855 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6856</pre>
6857
6858<h5>Overview:</h5>
6859
6860<p>
6861The '<tt>llvm.var.annotation</tt>' intrinsic
6862</p>
6863
6864<h5>Arguments:</h5>
6865
6866<p>
6867The first argument is a pointer to a value, the second is a pointer to a
6868global string, the third is a pointer to a global string which is the source
6869file name, and the last argument is the line number.
6870</p>
6871
6872<h5>Semantics:</h5>
6873
6874<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6875This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6876This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6877annotations. These have no other defined use, they are ignored by code
6878generation and optimization.
6879</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6880</div>
6881
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6882<!-- _______________________________________________________________________ -->
6883<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6884 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6885</div>
6886
6887<div class="doc_text">
6888
6889<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6890<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6891any integer bit width.
6892</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6893<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6894 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6895 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6896 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6897 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6898 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]6899</pre>
6900
6901<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6902
6903<p>
6904The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6905</p>
6906
6907<h5>Arguments:</h5>
6908
6909<p>
6910The first argument is an integer value (result of some expression),
6911the second is a pointer to a global string, the third is a pointer to a global
6912string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6913It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6914</p>
6915
6916<h5>Semantics:</h5>
6917
6918<p>
6919This intrinsic allows annotations to be put on arbitrary expressions
6920with arbitrary strings. This can be useful for special purpose optimizations
6921that want to look for these annotations. These have no other defined use, they
6922are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6923</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6924</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6925
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6926<!-- _______________________________________________________________________ -->
6927<div class="doc_subsubsection">
6928 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6929</div>
6930
6931<div class="doc_text">
6932
6933<h5>Syntax:</h5>
6934<pre>
6935 declare void @llvm.trap()
6936</pre>
6937
6938<h5>Overview:</h5>
6939
6940<p>
6941The '<tt>llvm.trap</tt>' intrinsic
6942</p>
6943
6944<h5>Arguments:</h5>
6945
6946<p>
6947None
6948</p>
6949
6950<h5>Semantics:</h5>
6951
6952<p>
6953This intrinsics is lowered to the target dependent trap instruction. If the
6954target does not have a trap instruction, this intrinsic will be lowered to the
6955call of the abort() function.
6956</p>
6957</div>
6958
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6959<!-- _______________________________________________________________________ -->
6960<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6961 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6962</div>
6963<div class="doc_text">
6964<h5>Syntax:</h5>
6965<pre>
6966declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6967
6968</pre>
6969<h5>Overview:</h5>
6970<p>
6971 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6972 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6973 it is placed on the stack before local variables.
6974</p>
6975<h5>Arguments:</h5>
6976<p>
6977 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6978 first argument is the value loaded from the stack guard
6979 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6980 has enough space to hold the value of the guard.
6981</p>
6982<h5>Semantics:</h5>
6983<p>
6984 This intrinsic causes the prologue/epilogue inserter to force the position of
6985 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6986 stack. This is to ensure that if a local variable on the stack is overwritten,
6987 it will destroy the value of the guard. When the function exits, the guard on
6988 the stack is checked against the original guard. If they're different, then
6989 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6990</p>
6991</div>
6992
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6993<!-- *********************************************************************** -->
6994<hr>
6995<address>
6996 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6997 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6998 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6999 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]7000
7001 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7002 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7003 Last modified: $Date$
7004</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7005
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7006</body>
7007</html>