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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 557bc5dc855e8ed0ed31e9f3db8bc68ae9d55702 / . / docs / LangRef.html
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4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]25 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26 <li><a href="#globalvars">Global Variables</a></li>
27 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]28 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]30 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]31 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]32 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
33 <li><a href="#datalayout">Data Layout</a></li>
34 </ol>
35 </li>
36 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]38 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39 <li><a href="#t_primitive">Primitive Types</a>
40 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]41 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]44 </ol>
45 </li>
46 <li><a href="#t_derived">Derived Types</a>
47 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]48 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]49 <li><a href="#t_array">Array Type</a></li>
50 <li><a href="#t_function">Function Type</a></li>
51 <li><a href="#t_pointer">Pointer Type</a></li>
52 <li><a href="#t_struct">Structure Type</a></li>
53 <li><a href="#t_pstruct">Packed Structure Type</a></li>
54 <li><a href="#t_vector">Vector Type</a></li>
55 <li><a href="#t_opaque">Opaque Type</a></li>
56 </ol>
57 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]58 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]59 </ol>
60 </li>
61 <li><a href="#constants">Constants</a>
62 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]63 <li><a href="#simpleconstants">Simple Constants</a></li>
64 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
65 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
66 <li><a href="#undefvalues">Undefined Values</a></li>
67 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]68 </ol>
69 </li>
70 <li><a href="#othervalues">Other Values</a>
71 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]72 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]73 </ol>
74 </li>
75 <li><a href="#instref">Instruction Reference</a>
76 <ol>
77 <li><a href="#terminators">Terminator Instructions</a>
78 <ol>
79 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
80 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
81 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
82 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
83 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
84 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
85 </ol>
86 </li>
87 <li><a href="#binaryops">Binary Operations</a>
88 <ol>
89 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
90 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
91 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
92 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
93 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
94 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
95 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
96 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
97 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
98 </ol>
99 </li>
100 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
101 <ol>
102 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
103 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
104 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
105 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
106 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
107 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
108 </ol>
109 </li>
110 <li><a href="#vectorops">Vector Operations</a>
111 <ol>
112 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
113 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
114 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
115 </ol>
116 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]117 <li><a href="#aggregateops">Aggregate Operations</a>
118 <ol>
119 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
120 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
121 </ol>
122 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]123 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
124 <ol>
125 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
126 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
127 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
128 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
129 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
130 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
131 </ol>
132 </li>
133 <li><a href="#convertops">Conversion Operations</a>
134 <ol>
135 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
136 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
137 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
141 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
142 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
143 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
144 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
145 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
146 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
147 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]148 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]149 <li><a href="#otherops">Other Operations</a>
150 <ol>
151 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
152 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]153 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
154 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]155 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
156 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
157 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
158 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
159 </ol>
160 </li>
161 </ol>
162 </li>
163 <li><a href="#intrinsics">Intrinsic Functions</a>
164 <ol>
165 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
166 <ol>
167 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
168 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
169 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
170 </ol>
171 </li>
172 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
173 <ol>
174 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
175 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
176 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
177 </ol>
178 </li>
179 <li><a href="#int_codegen">Code Generator Intrinsics</a>
180 <ol>
181 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
182 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
183 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
184 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
185 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
186 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
187 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
188 </ol>
189 </li>
190 <li><a href="#int_libc">Standard C Library Intrinsics</a>
191 <ol>
192 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]197 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]200 </ol>
201 </li>
202 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
203 <ol>
204 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
205 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
209 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
210 </ol>
211 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]212 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
213 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]214 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
215 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]219 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]220 </ol>
221 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]222 <li><a href="#int_debugger">Debugger intrinsics</a></li>
223 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]224 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]225 <ol>
226 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]227 </ol>
228 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]229 <li><a href="#int_atomics">Atomic intrinsics</a>
230 <ol>
231 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
232 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
233 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
234 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
235 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
236 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
237 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
238 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
239 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
240 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
241 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
242 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
243 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
244 </ol>
245 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]246 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]247 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]248 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]249 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]250 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]251 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]252 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]253 '<tt>llvm.trap</tt>' Intrinsic</a></li>
254 <li><a href="#int_stackprotector">
255 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]256 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]257 </li>
258 </ol>
259 </li>
260</ol>
261
262<div class="doc_author">
263 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
264 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
265</div>
266
267<!-- *********************************************************************** -->
268<div class="doc_section"> <a name="abstract">Abstract </a></div>
269<!-- *********************************************************************** -->
270
271<div class="doc_text">
272<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]273LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]274type safety, low-level operations, flexibility, and the capability of
275representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]276representation used throughout all phases of the LLVM compilation
277strategy.</p>
278</div>
279
280<!-- *********************************************************************** -->
281<div class="doc_section"> <a name="introduction">Introduction</a> </div>
282<!-- *********************************************************************** -->
283
284<div class="doc_text">
285
286<p>The LLVM code representation is designed to be used in three
287different forms: as an in-memory compiler IR, as an on-disk bitcode
288representation (suitable for fast loading by a Just-In-Time compiler),
289and as a human readable assembly language representation. This allows
290LLVM to provide a powerful intermediate representation for efficient
291compiler transformations and analysis, while providing a natural means
292to debug and visualize the transformations. The three different forms
293of LLVM are all equivalent. This document describes the human readable
294representation and notation.</p>
295
296<p>The LLVM representation aims to be light-weight and low-level
297while being expressive, typed, and extensible at the same time. It
298aims to be a "universal IR" of sorts, by being at a low enough level
299that high-level ideas may be cleanly mapped to it (similar to how
300microprocessors are "universal IR's", allowing many source languages to
301be mapped to them). By providing type information, LLVM can be used as
302the target of optimizations: for example, through pointer analysis, it
303can be proven that a C automatic variable is never accessed outside of
304the current function... allowing it to be promoted to a simple SSA
305value instead of a memory location.</p>
306
307</div>
308
309<!-- _______________________________________________________________________ -->
310<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
311
312<div class="doc_text">
313
314<p>It is important to note that this document describes 'well formed'
315LLVM assembly language. There is a difference between what the parser
316accepts and what is considered 'well formed'. For example, the
317following instruction is syntactically okay, but not well formed:</p>
318
319<div class="doc_code">
320<pre>
321%x = <a href="#i_add">add</a> i32 1, %x
322</pre>
323</div>
324
325<p>...because the definition of <tt>%x</tt> does not dominate all of
326its uses. The LLVM infrastructure provides a verification pass that may
327be used to verify that an LLVM module is well formed. This pass is
328automatically run by the parser after parsing input assembly and by
329the optimizer before it outputs bitcode. The violations pointed out
330by the verifier pass indicate bugs in transformation passes or input to
331the parser.</p>
332</div>
333
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]334<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]335
336<!-- *********************************************************************** -->
337<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
338<!-- *********************************************************************** -->
339
340<div class="doc_text">
341
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]342 <p>LLVM identifiers come in two basic types: global and local. Global
343 identifiers (functions, global variables) begin with the @ character. Local
344 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]345 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]348 <li>Named values are represented as a string of characters with their prefix.
349 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
350 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]351 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]352 with quotes. Special characters may be escaped using "\xx" where xx is the
353 ASCII code for the character in hexadecimal. In this way, any character can
354 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]355
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]356 <li>Unnamed values are represented as an unsigned numeric value with their
357 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]358
359 <li>Constants, which are described in a <a href="#constants">section about
360 constants</a>, below.</li>
361</ol>
362
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]363<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]364don't need to worry about name clashes with reserved words, and the set of
365reserved words may be expanded in the future without penalty. Additionally,
366unnamed identifiers allow a compiler to quickly come up with a temporary
367variable without having to avoid symbol table conflicts.</p>
368
369<p>Reserved words in LLVM are very similar to reserved words in other
370languages. There are keywords for different opcodes
371('<tt><a href="#i_add">add</a></tt>',
372 '<tt><a href="#i_bitcast">bitcast</a></tt>',
373 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
374href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
375and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]376none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]377
378<p>Here is an example of LLVM code to multiply the integer variable
379'<tt>%X</tt>' by 8:</p>
380
381<p>The easy way:</p>
382
383<div class="doc_code">
384<pre>
385%result = <a href="#i_mul">mul</a> i32 %X, 8
386</pre>
387</div>
388
389<p>After strength reduction:</p>
390
391<div class="doc_code">
392<pre>
393%result = <a href="#i_shl">shl</a> i32 %X, i8 3
394</pre>
395</div>
396
397<p>And the hard way:</p>
398
399<div class="doc_code">
400<pre>
401<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
402<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
403%result = <a href="#i_add">add</a> i32 %1, %1
404</pre>
405</div>
406
407<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
408important lexical features of LLVM:</p>
409
410<ol>
411
412 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
413 line.</li>
414
415 <li>Unnamed temporaries are created when the result of a computation is not
416 assigned to a named value.</li>
417
418 <li>Unnamed temporaries are numbered sequentially</li>
419
420</ol>
421
422<p>...and it also shows a convention that we follow in this document. When
423demonstrating instructions, we will follow an instruction with a comment that
424defines the type and name of value produced. Comments are shown in italic
425text.</p>
426
427</div>
428
429<!-- *********************************************************************** -->
430<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
431<!-- *********************************************************************** -->
432
433<!-- ======================================================================= -->
434<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
435</div>
436
437<div class="doc_text">
438
439<p>LLVM programs are composed of "Module"s, each of which is a
440translation unit of the input programs. Each module consists of
441functions, global variables, and symbol table entries. Modules may be
442combined together with the LLVM linker, which merges function (and
443global variable) definitions, resolves forward declarations, and merges
444symbol table entries. Here is an example of the "hello world" module:</p>
445
446<div class="doc_code">
447<pre><i>; Declare the string constant as a global constant...</i>
448<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
449 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
450
451<i>; External declaration of the puts function</i>
452<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
453
454<i>; Definition of main function</i>
455define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]456 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]457 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]458 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]459
460 <i>; Call puts function to write out the string to stdout...</i>
461 <a
462 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
463 <a
464 href="#i_ret">ret</a> i32 0<br>}<br>
465</pre>
466</div>
467
468<p>This example is made up of a <a href="#globalvars">global variable</a>
469named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
470function, and a <a href="#functionstructure">function definition</a>
471for "<tt>main</tt>".</p>
472
473<p>In general, a module is made up of a list of global values,
474where both functions and global variables are global values. Global values are
475represented by a pointer to a memory location (in this case, a pointer to an
476array of char, and a pointer to a function), and have one of the following <a
477href="#linkage">linkage types</a>.</p>
478
479</div>
480
481<!-- ======================================================================= -->
482<div class="doc_subsection">
483 <a name="linkage">Linkage Types</a>
484</div>
485
486<div class="doc_text">
487
488<p>
489All Global Variables and Functions have one of the following types of linkage:
490</p>
491
492<dl>
493
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]494 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
495
496 <dd>Global values with private linkage are only directly accessible by
497 objects in the current module. In particular, linking code into a module with
498 an private global value may cause the private to be renamed as necessary to
499 avoid collisions. Because the symbol is private to the module, all
500 references can be updated. This doesn't show up in any symbol table in the
501 object file.
502 </dd>
503
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]504 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]505
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]506 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]507 the case of ELF) in the object file. This corresponds to the notion of the
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]508 '<tt>static</tt>' keyword in C.
509 </dd>
510
511 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
512
513 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
514 the same name when linkage occurs. This is typically used to implement
515 inline functions, templates, or other code which must be generated in each
516 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
517 allowed to be discarded.
518 </dd>
519
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]520 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
521
522 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
523 linkage, except that unreferenced <tt>common</tt> globals may not be
524 discarded. This is used for globals that may be emitted in multiple
525 translation units, but that are not guaranteed to be emitted into every
526 translation unit that uses them. One example of this is tentative
527 definitions in C, such as "<tt>int X;</tt>" at global scope.
528 </dd>
529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]530 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
531
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]532 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
533 that some targets may choose to emit different assembly sequences for them
534 for target-dependent reasons. This is used for globals that are declared
535 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]536 </dd>
537
538 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
539
540 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
541 pointer to array type. When two global variables with appending linkage are
542 linked together, the two global arrays are appended together. This is the
543 LLVM, typesafe, equivalent of having the system linker append together
544 "sections" with identical names when .o files are linked.
545 </dd>
546
547 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]548 <dd>The semantics of this linkage follow the ELF object file model: the
549 symbol is weak until linked, if not linked, the symbol becomes null instead
550 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]551 </dd>
552
553 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
554
555 <dd>If none of the above identifiers are used, the global is externally
556 visible, meaning that it participates in linkage and can be used to resolve
557 external symbol references.
558 </dd>
559</dl>
560
561 <p>
562 The next two types of linkage are targeted for Microsoft Windows platform
563 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]564 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]565 </p>
566
567 <dl>
568 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
569
570 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
571 or variable via a global pointer to a pointer that is set up by the DLL
572 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]573 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]574 </dd>
575
576 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
577
578 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
579 pointer to a pointer in a DLL, so that it can be referenced with the
580 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]581 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]582 name.
583 </dd>
584
585</dl>
586
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]587<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]588variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
589variable and was linked with this one, one of the two would be renamed,
590preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
591external (i.e., lacking any linkage declarations), they are accessible
592outside of the current module.</p>
593<p>It is illegal for a function <i>declaration</i>
594to have any linkage type other than "externally visible", <tt>dllimport</tt>,
595or <tt>extern_weak</tt>.</p>
596<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]597linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]598</div>
599
600<!-- ======================================================================= -->
601<div class="doc_subsection">
602 <a name="callingconv">Calling Conventions</a>
603</div>
604
605<div class="doc_text">
606
607<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
608and <a href="#i_invoke">invokes</a> can all have an optional calling convention
609specified for the call. The calling convention of any pair of dynamic
610caller/callee must match, or the behavior of the program is undefined. The
611following calling conventions are supported by LLVM, and more may be added in
612the future:</p>
613
614<dl>
615 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
616
617 <dd>This calling convention (the default if no other calling convention is
618 specified) matches the target C calling conventions. This calling convention
619 supports varargs function calls and tolerates some mismatch in the declared
620 prototype and implemented declaration of the function (as does normal C).
621 </dd>
622
623 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
624
625 <dd>This calling convention attempts to make calls as fast as possible
626 (e.g. by passing things in registers). This calling convention allows the
627 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]628 without having to conform to an externally specified ABI (Application Binary
629 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]630 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
631 supported. This calling convention does not support varargs and requires the
632 prototype of all callees to exactly match the prototype of the function
633 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]634 </dd>
635
636 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
637
638 <dd>This calling convention attempts to make code in the caller as efficient
639 as possible under the assumption that the call is not commonly executed. As
640 such, these calls often preserve all registers so that the call does not break
641 any live ranges in the caller side. This calling convention does not support
642 varargs and requires the prototype of all callees to exactly match the
643 prototype of the function definition.
644 </dd>
645
646 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
647
648 <dd>Any calling convention may be specified by number, allowing
649 target-specific calling conventions to be used. Target specific calling
650 conventions start at 64.
651 </dd>
652</dl>
653
654<p>More calling conventions can be added/defined on an as-needed basis, to
655support pascal conventions or any other well-known target-independent
656convention.</p>
657
658</div>
659
660<!-- ======================================================================= -->
661<div class="doc_subsection">
662 <a name="visibility">Visibility Styles</a>
663</div>
664
665<div class="doc_text">
666
667<p>
668All Global Variables and Functions have one of the following visibility styles:
669</p>
670
671<dl>
672 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
673
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]674 <dd>On targets that use the ELF object file format, default visibility means
675 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]676 modules and, in shared libraries, means that the declared entity may be
677 overridden. On Darwin, default visibility means that the declaration is
678 visible to other modules. Default visibility corresponds to "external
679 linkage" in the language.
680 </dd>
681
682 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
683
684 <dd>Two declarations of an object with hidden visibility refer to the same
685 object if they are in the same shared object. Usually, hidden visibility
686 indicates that the symbol will not be placed into the dynamic symbol table,
687 so no other module (executable or shared library) can reference it
688 directly.
689 </dd>
690
691 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
692
693 <dd>On ELF, protected visibility indicates that the symbol will be placed in
694 the dynamic symbol table, but that references within the defining module will
695 bind to the local symbol. That is, the symbol cannot be overridden by another
696 module.
697 </dd>
698</dl>
699
700</div>
701
702<!-- ======================================================================= -->
703<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]704 <a name="namedtypes">Named Types</a>
705</div>
706
707<div class="doc_text">
708
709<p>LLVM IR allows you to specify name aliases for certain types. This can make
710it easier to read the IR and make the IR more condensed (particularly when
711recursive types are involved). An example of a name specification is:
712</p>
713
714<div class="doc_code">
715<pre>
716%mytype = type { %mytype*, i32 }
717</pre>
718</div>
719
720<p>You may give a name to any <a href="#typesystem">type</a> except "<a
721href="t_void">void</a>". Type name aliases may be used anywhere a type is
722expected with the syntax "%mytype".</p>
723
724<p>Note that type names are aliases for the structural type that they indicate,
725and that you can therefore specify multiple names for the same type. This often
726leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
727structural typing, the name is not part of the type. When printing out LLVM IR,
728the printer will pick <em>one name</em> to render all types of a particular
729shape. This means that if you have code where two different source types end up
730having the same LLVM type, that the dumper will sometimes print the "wrong" or
731unexpected type. This is an important design point and isn't going to
732change.</p>
733
734</div>
735
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]736<!-- ======================================================================= -->
737<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]738 <a name="globalvars">Global Variables</a>
739</div>
740
741<div class="doc_text">
742
743<p>Global variables define regions of memory allocated at compilation time
744instead of run-time. Global variables may optionally be initialized, may have
745an explicit section to be placed in, and may have an optional explicit alignment
746specified. A variable may be defined as "thread_local", which means that it
747will not be shared by threads (each thread will have a separated copy of the
748variable). A variable may be defined as a global "constant," which indicates
749that the contents of the variable will <b>never</b> be modified (enabling better
750optimization, allowing the global data to be placed in the read-only section of
751an executable, etc). Note that variables that need runtime initialization
752cannot be marked "constant" as there is a store to the variable.</p>
753
754<p>
755LLVM explicitly allows <em>declarations</em> of global variables to be marked
756constant, even if the final definition of the global is not. This capability
757can be used to enable slightly better optimization of the program, but requires
758the language definition to guarantee that optimizations based on the
759'constantness' are valid for the translation units that do not include the
760definition.
761</p>
762
763<p>As SSA values, global variables define pointer values that are in
764scope (i.e. they dominate) all basic blocks in the program. Global
765variables always define a pointer to their "content" type because they
766describe a region of memory, and all memory objects in LLVM are
767accessed through pointers.</p>
768
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]769<p>A global variable may be declared to reside in a target-specifc numbered
770address space. For targets that support them, address spaces may affect how
771optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]772the variable. The default address space is zero. The address space qualifier
773must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]774
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]775<p>LLVM allows an explicit section to be specified for globals. If the target
776supports it, it will emit globals to the section specified.</p>
777
778<p>An explicit alignment may be specified for a global. If not present, or if
779the alignment is set to zero, the alignment of the global is set by the target
780to whatever it feels convenient. If an explicit alignment is specified, the
781global is forced to have at least that much alignment. All alignments must be
782a power of 2.</p>
783
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]784<p>For example, the following defines a global in a numbered address space with
785an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]786
787<div class="doc_code">
788<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]789@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]790</pre>
791</div>
792
793</div>
794
795
796<!-- ======================================================================= -->
797<div class="doc_subsection">
798 <a name="functionstructure">Functions</a>
799</div>
800
801<div class="doc_text">
802
803<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
804an optional <a href="#linkage">linkage type</a>, an optional
805<a href="#visibility">visibility style</a>, an optional
806<a href="#callingconv">calling convention</a>, a return type, an optional
807<a href="#paramattrs">parameter attribute</a> for the return type, a function
808name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]809<a href="#paramattrs">parameter attributes</a>), optional
810<a href="#fnattrs">function attributes</a>, an optional section,
811an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]812an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]813
814LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
815optional <a href="#linkage">linkage type</a>, an optional
816<a href="#visibility">visibility style</a>, an optional
817<a href="#callingconv">calling convention</a>, a return type, an optional
818<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]819name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]820<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]821
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]822<p>A function definition contains a list of basic blocks, forming the CFG
823(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]824the function. Each basic block may optionally start with a label (giving the
825basic block a symbol table entry), contains a list of instructions, and ends
826with a <a href="#terminators">terminator</a> instruction (such as a branch or
827function return).</p>
828
829<p>The first basic block in a function is special in two ways: it is immediately
830executed on entrance to the function, and it is not allowed to have predecessor
831basic blocks (i.e. there can not be any branches to the entry block of a
832function). Because the block can have no predecessors, it also cannot have any
833<a href="#i_phi">PHI nodes</a>.</p>
834
835<p>LLVM allows an explicit section to be specified for functions. If the target
836supports it, it will emit functions to the section specified.</p>
837
838<p>An explicit alignment may be specified for a function. If not present, or if
839the alignment is set to zero, the alignment of the function is set by the target
840to whatever it feels convenient. If an explicit alignment is specified, the
841function is forced to have at least that much alignment. All alignments must be
842a power of 2.</p>
843
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]844 <h5>Syntax:</h5>
845
846<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]847<tt>
848define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
849 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
850 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
851 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
852 [<a href="#gc">gc</a>] { ... }
853</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]854</div>
855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]856</div>
857
858
859<!-- ======================================================================= -->
860<div class="doc_subsection">
861 <a name="aliasstructure">Aliases</a>
862</div>
863<div class="doc_text">
864 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]865 function, global variable, another alias or bitcast of global value). Aliases
866 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]867 optional <a href="#visibility">visibility style</a>.</p>
868
869 <h5>Syntax:</h5>
870
871<div class="doc_code">
872<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]873@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]874</pre>
875</div>
876
877</div>
878
879
880
881<!-- ======================================================================= -->
882<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
883<div class="doc_text">
884 <p>The return type and each parameter of a function type may have a set of
885 <i>parameter attributes</i> associated with them. Parameter attributes are
886 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]887 a function. Parameter attributes are considered to be part of the function,
888 not of the function type, so functions with different parameter attributes
889 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]890
891 <p>Parameter attributes are simple keywords that follow the type specified. If
892 multiple parameter attributes are needed, they are space separated. For
893 example:</p>
894
895<div class="doc_code">
896<pre>
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>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame^]1950 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
1951 are the same as those for the <a href="#i_bitcast">bitcast
1952 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1953
1954 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1955
1956 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1957 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1958 instruction, the index list may have zero or more indexes, which are required
1959 to make sense for the type of "CSTPTR".</dd>
1960
1961 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1962
1963 <dd>Perform the <a href="#i_select">select operation</a> on
1964 constants.</dd>
1965
1966 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1967 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1968
1969 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1970 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1971
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1972 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1973 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1974
1975 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1976 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1977
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1978 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1979
1980 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1981 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1982
1983 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1984
1985 <dd>Perform the <a href="#i_insertelement">insertelement
1986 operation</a> on constants.</dd>
1987
1988
1989 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1990
1991 <dd>Perform the <a href="#i_shufflevector">shufflevector
1992 operation</a> on constants.</dd>
1993
1994 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1995
1996 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1997 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1998 binary</a> operations. The constraints on operands are the same as those for
1999 the corresponding instruction (e.g. no bitwise operations on floating point
2000 values are allowed).</dd>
2001</dl>
2002</div>
2003
2004<!-- *********************************************************************** -->
2005<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2006<!-- *********************************************************************** -->
2007
2008<!-- ======================================================================= -->
2009<div class="doc_subsection">
2010<a name="inlineasm">Inline Assembler Expressions</a>
2011</div>
2012
2013<div class="doc_text">
2014
2015<p>
2016LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2017Module-Level Inline Assembly</a>) through the use of a special value. This
2018value represents the inline assembler as a string (containing the instructions
2019to emit), a list of operand constraints (stored as a string), and a flag that
2020indicates whether or not the inline asm expression has side effects. An example
2021inline assembler expression is:
2022</p>
2023
2024<div class="doc_code">
2025<pre>
2026i32 (i32) asm "bswap $0", "=r,r"
2027</pre>
2028</div>
2029
2030<p>
2031Inline assembler expressions may <b>only</b> be used as the callee operand of
2032a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2033</p>
2034
2035<div class="doc_code">
2036<pre>
2037%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2038</pre>
2039</div>
2040
2041<p>
2042Inline asms with side effects not visible in the constraint list must be marked
2043as having side effects. This is done through the use of the
2044'<tt>sideeffect</tt>' keyword, like so:
2045</p>
2046
2047<div class="doc_code">
2048<pre>
2049call void asm sideeffect "eieio", ""()
2050</pre>
2051</div>
2052
2053<p>TODO: The format of the asm and constraints string still need to be
2054documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2055need to be documented). This is probably best done by reference to another
2056document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2057</p>
2058
2059</div>
2060
2061<!-- *********************************************************************** -->
2062<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2063<!-- *********************************************************************** -->
2064
2065<div class="doc_text">
2066
2067<p>The LLVM instruction set consists of several different
2068classifications of instructions: <a href="#terminators">terminator
2069instructions</a>, <a href="#binaryops">binary instructions</a>,
2070<a href="#bitwiseops">bitwise binary instructions</a>, <a
2071 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2072instructions</a>.</p>
2073
2074</div>
2075
2076<!-- ======================================================================= -->
2077<div class="doc_subsection"> <a name="terminators">Terminator
2078Instructions</a> </div>
2079
2080<div class="doc_text">
2081
2082<p>As mentioned <a href="#functionstructure">previously</a>, every
2083basic block in a program ends with a "Terminator" instruction, which
2084indicates which block should be executed after the current block is
2085finished. These terminator instructions typically yield a '<tt>void</tt>'
2086value: they produce control flow, not values (the one exception being
2087the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2088<p>There are six different terminator instructions: the '<a
2089 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2090instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2091the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2092 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2093 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2094
2095</div>
2096
2097<!-- _______________________________________________________________________ -->
2098<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2099Instruction</a> </div>
2100<div class="doc_text">
2101<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2102<pre>
2103 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]2104 ret void <i>; Return from void function</i>
2105</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2106
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2107<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2108
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2109<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2110optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2111<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2112returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2113control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2114
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2115<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2116
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2117<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2118the return value. The type of the return value must be a
2119'<a href="#t_firstclass">first class</a>' type.</p>
2120
2121<p>A function is not <a href="#wellformed">well formed</a> if
2122it it has a non-void return type and contains a '<tt>ret</tt>'
2123instruction with no return value or a return value with a type that
2124does not match its type, or if it has a void return type and contains
2125a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2127<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2128
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2129<p>When the '<tt>ret</tt>' instruction is executed, control flow
2130returns back to the calling function's context. If the caller is a "<a
2131 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2132the instruction after the call. If the caller was an "<a
2133 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2134at the beginning of the "normal" destination block. If the instruction
2135returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2136return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2137
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2138<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2139
2140<pre>
2141 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2142 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2143 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]2144</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2145
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2146<p>Note that the code generator does not yet fully support large
2147 return values. The specific sizes that are currently supported are
2148 dependent on the target. For integers, on 32-bit targets the limit
2149 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2150 For aggregate types, the current limits are dependent on the element
2151 types; for example targets are often limited to 2 total integer
2152 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2153
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2154</div>
2155<!-- _______________________________________________________________________ -->
2156<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2157<div class="doc_text">
2158<h5>Syntax:</h5>
2159<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2160</pre>
2161<h5>Overview:</h5>
2162<p>The '<tt>br</tt>' instruction is used to cause control flow to
2163transfer to a different basic block in the current function. There are
2164two forms of this instruction, corresponding to a conditional branch
2165and an unconditional branch.</p>
2166<h5>Arguments:</h5>
2167<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2168single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2169unconditional form of the '<tt>br</tt>' instruction takes a single
2170'<tt>label</tt>' value as a target.</p>
2171<h5>Semantics:</h5>
2172<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2173argument is evaluated. If the value is <tt>true</tt>, control flows
2174to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2175control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2176<h5>Example:</h5>
2177<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
2178 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2179</div>
2180<!-- _______________________________________________________________________ -->
2181<div class="doc_subsubsection">
2182 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2183</div>
2184
2185<div class="doc_text">
2186<h5>Syntax:</h5>
2187
2188<pre>
2189 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2190</pre>
2191
2192<h5>Overview:</h5>
2193
2194<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2195several different places. It is a generalization of the '<tt>br</tt>'
2196instruction, allowing a branch to occur to one of many possible
2197destinations.</p>
2198
2199
2200<h5>Arguments:</h5>
2201
2202<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2203comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2204an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2205table is not allowed to contain duplicate constant entries.</p>
2206
2207<h5>Semantics:</h5>
2208
2209<p>The <tt>switch</tt> instruction specifies a table of values and
2210destinations. When the '<tt>switch</tt>' instruction is executed, this
2211table is searched for the given value. If the value is found, control flow is
2212transfered to the corresponding destination; otherwise, control flow is
2213transfered to the default destination.</p>
2214
2215<h5>Implementation:</h5>
2216
2217<p>Depending on properties of the target machine and the particular
2218<tt>switch</tt> instruction, this instruction may be code generated in different
2219ways. For example, it could be generated as a series of chained conditional
2220branches or with a lookup table.</p>
2221
2222<h5>Example:</h5>
2223
2224<pre>
2225 <i>; Emulate a conditional br instruction</i>
2226 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2227 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2228
2229 <i>; Emulate an unconditional br instruction</i>
2230 switch i32 0, label %dest [ ]
2231
2232 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2233 switch i32 %val, label %otherwise [ i32 0, label %onzero
2234 i32 1, label %onone
2235 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2236</pre>
2237</div>
2238
2239<!-- _______________________________________________________________________ -->
2240<div class="doc_subsubsection">
2241 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2242</div>
2243
2244<div class="doc_text">
2245
2246<h5>Syntax:</h5>
2247
2248<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2249 &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]2250 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2251</pre>
2252
2253<h5>Overview:</h5>
2254
2255<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2256function, with the possibility of control flow transfer to either the
2257'<tt>normal</tt>' label or the
2258'<tt>exception</tt>' label. If the callee function returns with the
2259"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2260"normal" label. If the callee (or any indirect callees) returns with the "<a
2261href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2262continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2263
2264<h5>Arguments:</h5>
2265
2266<p>This instruction requires several arguments:</p>
2267
2268<ol>
2269 <li>
2270 The optional "cconv" marker indicates which <a href="#callingconv">calling
2271 convention</a> the call should use. If none is specified, the call defaults
2272 to using C calling conventions.
2273 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2274
2275 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2276 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2277 and '<tt>inreg</tt>' attributes are valid here.</li>
2278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2280 function value being invoked. In most cases, this is a direct function
2281 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2282 an arbitrary pointer to function value.
2283 </li>
2284
2285 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2286 function to be invoked. </li>
2287
2288 <li>'<tt>function args</tt>': argument list whose types match the function
2289 signature argument types. If the function signature indicates the function
2290 accepts a variable number of arguments, the extra arguments can be
2291 specified. </li>
2292
2293 <li>'<tt>normal label</tt>': the label reached when the called function
2294 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2295
2296 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2297 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2298
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2299 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2300 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2301 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2302</ol>
2303
2304<h5>Semantics:</h5>
2305
2306<p>This instruction is designed to operate as a standard '<tt><a
2307href="#i_call">call</a></tt>' instruction in most regards. The primary
2308difference is that it establishes an association with a label, which is used by
2309the runtime library to unwind the stack.</p>
2310
2311<p>This instruction is used in languages with destructors to ensure that proper
2312cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2313exception. Additionally, this is important for implementation of
2314'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2315
2316<h5>Example:</h5>
2317<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2318 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2319 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2320 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321 unwind label %TestCleanup <i>; {i32}:retval set</i>
2322</pre>
2323</div>
2324
2325
2326<!-- _______________________________________________________________________ -->
2327
2328<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2329Instruction</a> </div>
2330
2331<div class="doc_text">
2332
2333<h5>Syntax:</h5>
2334<pre>
2335 unwind
2336</pre>
2337
2338<h5>Overview:</h5>
2339
2340<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2341at the first callee in the dynamic call stack which used an <a
2342href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2343primarily used to implement exception handling.</p>
2344
2345<h5>Semantics:</h5>
2346
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2347<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2348immediately halt. The dynamic call stack is then searched for the first <a
2349href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2350execution continues at the "exceptional" destination block specified by the
2351<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2352dynamic call chain, undefined behavior results.</p>
2353</div>
2354
2355<!-- _______________________________________________________________________ -->
2356
2357<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2358Instruction</a> </div>
2359
2360<div class="doc_text">
2361
2362<h5>Syntax:</h5>
2363<pre>
2364 unreachable
2365</pre>
2366
2367<h5>Overview:</h5>
2368
2369<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2370instruction is used to inform the optimizer that a particular portion of the
2371code is not reachable. This can be used to indicate that the code after a
2372no-return function cannot be reached, and other facts.</p>
2373
2374<h5>Semantics:</h5>
2375
2376<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2377</div>
2378
2379
2380
2381<!-- ======================================================================= -->
2382<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2383<div class="doc_text">
2384<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2385program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2386produce a single value. The operands might represent
2387multiple 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]2388The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389<p>There are several different binary operators:</p>
2390</div>
2391<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2392<div class="doc_subsubsection">
2393 <a name="i_add">'<tt>add</tt>' Instruction</a>
2394</div>
2395
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2396<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2399
2400<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2401 &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]2402</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2406<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2407
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2408<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2409
2410<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2411 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2412 <a href="#t_vector">vector</a> values. Both arguments must have identical
2413 types.</p>
2414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2415<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2416
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2417<p>The value produced is the integer or floating point sum of the two
2418operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2419
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2420<p>If an integer sum has unsigned overflow, the result returned is the
2421mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2422the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2423
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2424<p>Because LLVM integers use a two's complement representation, this
2425instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2427<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2428
2429<pre>
2430 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2431</pre>
2432</div>
2433<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2434<div class="doc_subsubsection">
2435 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2436</div>
2437
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2438<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2439
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2440<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2441
2442<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2443 &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]2444</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2445
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2446<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2447
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2448<p>The '<tt>sub</tt>' instruction returns the difference of its two
2449operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2450
2451<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2452'<tt>neg</tt>' instruction present in most other intermediate
2453representations.</p>
2454
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2455<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2456
2457<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2458 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2459 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2460 types.</p>
2461
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2462<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2464<p>The value produced is the integer or floating point difference of
2465the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2466
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2467<p>If an integer difference has unsigned overflow, the result returned is the
2468mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2469the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2470
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2471<p>Because LLVM integers use a two's complement representation, this
2472instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2473
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2474<h5>Example:</h5>
2475<pre>
2476 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2477 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2478</pre>
2479</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2480
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2481<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2482<div class="doc_subsubsection">
2483 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2484</div>
2485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2486<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2488<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2489<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]2490</pre>
2491<h5>Overview:</h5>
2492<p>The '<tt>mul</tt>' instruction returns the product of its two
2493operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2495<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2496
2497<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2498href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2499or <a href="#t_vector">vector</a> values. Both arguments must have identical
2500types.</p>
2501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2502<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2503
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2504<p>The value produced is the integer or floating point product of the
2505two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2506
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2507<p>If the result of an integer multiplication has unsigned overflow,
2508the result returned is the mathematical result modulo
25092<sup>n</sup>, where n is the bit width of the result.</p>
2510<p>Because LLVM integers use a two's complement representation, and the
2511result is the same width as the operands, this instruction returns the
2512correct result for both signed and unsigned integers. If a full product
2513(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2514should be sign-extended or zero-extended as appropriate to the
2515width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2516<h5>Example:</h5>
2517<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2518</pre>
2519</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2521<!-- _______________________________________________________________________ -->
2522<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2523</a></div>
2524<div class="doc_text">
2525<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2526<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]2527</pre>
2528<h5>Overview:</h5>
2529<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2530operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2531
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2532<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2534<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2535<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2536values. Both arguments must have identical types.</p>
2537
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2538<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2539
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2540<p>The value produced is the unsigned integer quotient of the two operands.</p>
2541<p>Note that unsigned integer division and signed integer division are distinct
2542operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2543<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2544<h5>Example:</h5>
2545<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2546</pre>
2547</div>
2548<!-- _______________________________________________________________________ -->
2549<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2550</a> </div>
2551<div class="doc_text">
2552<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2553<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2554 &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]2555</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2556
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2557<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2558
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2559<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2560operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2561
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2562<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2563
2564<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2565<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2566values. Both arguments must have identical types.</p>
2567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2568<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2569<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]2570<p>Note that signed integer division and unsigned integer division are distinct
2571operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2572<p>Division by zero leads to undefined behavior. Overflow also leads to
2573undefined behavior; this is a rare case, but can occur, for example,
2574by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2575<h5>Example:</h5>
2576<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2577</pre>
2578</div>
2579<!-- _______________________________________________________________________ -->
2580<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2581Instruction</a> </div>
2582<div class="doc_text">
2583<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2584<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2585 &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]2586</pre>
2587<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2590operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2591
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2592<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2593
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2595<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2596of floating point values. Both arguments must have identical types.</p>
2597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2598<h5>Semantics:</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 value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2602<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2603
2604<pre>
2605 &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]2606</pre>
2607</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2608
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2609<!-- _______________________________________________________________________ -->
2610<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2611</div>
2612<div class="doc_text">
2613<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2614<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]2615</pre>
2616<h5>Overview:</h5>
2617<p>The '<tt>urem</tt>' instruction returns the remainder from the
2618unsigned division of its two arguments.</p>
2619<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2620<p>The two arguments to the '<tt>urem</tt>' instruction must be
2621<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2622values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2623<h5>Semantics:</h5>
2624<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2625This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2626<p>Note that unsigned integer remainder and signed integer remainder are
2627distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2628<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2629<h5>Example:</h5>
2630<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2631</pre>
2632
2633</div>
2634<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2635<div class="doc_subsubsection">
2636 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2637</div>
2638
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2639<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2640
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2641<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2642
2643<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2644 &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]2645</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2646
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2647<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2648
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2649<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2650signed division of its two operands. This instruction can also take
2651<a href="#t_vector">vector</a> versions of the values in which case
2652the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2653
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2655
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2656<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2657<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2658values. Both arguments must have identical types.</p>
2659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2663has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2664operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2665a value. For more information about the difference, see <a
2666 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2667Math Forum</a>. For a table of how this is implemented in various languages,
2668please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2669Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2670<p>Note that signed integer remainder and unsigned integer remainder are
2671distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2672<p>Taking the remainder of a division by zero leads to undefined behavior.
2673Overflow also leads to undefined behavior; this is a rare case, but can occur,
2674for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2675(The remainder doesn't actually overflow, but this rule lets srem be
2676implemented using instructions that return both the result of the division
2677and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2678<h5>Example:</h5>
2679<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2680</pre>
2681
2682</div>
2683<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2684<div class="doc_subsubsection">
2685 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2687<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2688
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2689<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2690<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]2691</pre>
2692<h5>Overview:</h5>
2693<p>The '<tt>frem</tt>' instruction returns the remainder from the
2694division of its two operands.</p>
2695<h5>Arguments:</h5>
2696<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2697<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2698of floating point values. Both arguments must have identical types.</p>
2699
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2700<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2701
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2702<p>This instruction returns the <i>remainder</i> of a division.
2703The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2705<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2706
2707<pre>
2708 &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]2709</pre>
2710</div>
2711
2712<!-- ======================================================================= -->
2713<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2714Operations</a> </div>
2715<div class="doc_text">
2716<p>Bitwise binary operators are used to do various forms of
2717bit-twiddling in a program. They are generally very efficient
2718instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2719instructions. They require two operands of the same type, execute an operation on them,
2720and 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]2721</div>
2722
2723<!-- _______________________________________________________________________ -->
2724<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2725Instruction</a> </div>
2726<div class="doc_text">
2727<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2728<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]2729</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2730
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2731<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2732
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2733<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2734the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2735
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2739 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2740type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2742<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2743
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2744<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2745where 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]2746equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2747If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2748corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2749
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2750<h5>Example:</h5><pre>
2751 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2752 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2753 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2754 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2755 &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]2756</pre>
2757</div>
2758<!-- _______________________________________________________________________ -->
2759<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2760Instruction</a> </div>
2761<div class="doc_text">
2762<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2763<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]2764</pre>
2765
2766<h5>Overview:</h5>
2767<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2768operand shifted to the right a specified number of bits with zero fill.</p>
2769
2770<h5>Arguments:</h5>
2771<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2772<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]2773type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2774
2775<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2777<p>This instruction always performs a logical shift right operation. The most
2778significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2779shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2780the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2781vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2782amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783
2784<h5>Example:</h5>
2785<pre>
2786 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2787 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2788 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2789 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2790 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2791 &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]2792</pre>
2793</div>
2794
2795<!-- _______________________________________________________________________ -->
2796<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2797Instruction</a> </div>
2798<div class="doc_text">
2799
2800<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2801<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]2802</pre>
2803
2804<h5>Overview:</h5>
2805<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2806operand shifted to the right a specified number of bits with sign extension.</p>
2807
2808<h5>Arguments:</h5>
2809<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2810<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]2811type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812
2813<h5>Semantics:</h5>
2814<p>This instruction always performs an arithmetic shift right operation,
2815The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2816of <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]2817larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2818arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2819corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2820
2821<h5>Example:</h5>
2822<pre>
2823 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2824 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2825 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2826 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2827 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2828 &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]2829</pre>
2830</div>
2831
2832<!-- _______________________________________________________________________ -->
2833<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2834Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2835
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2836<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2837
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2838<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2839
2840<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2841 &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]2842</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2843
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2844<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2845
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2846<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2847its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2848
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2849<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2850
2851<p>The two arguments to the '<tt>and</tt>' instruction must be
2852<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2853values. Both arguments must have identical types.</p>
2854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<h5>Semantics:</h5>
2856<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2857<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2858<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2859<table border="1" cellspacing="0" cellpadding="4">
2860 <tbody>
2861 <tr>
2862 <td>In0</td>
2863 <td>In1</td>
2864 <td>Out</td>
2865 </tr>
2866 <tr>
2867 <td>0</td>
2868 <td>0</td>
2869 <td>0</td>
2870 </tr>
2871 <tr>
2872 <td>0</td>
2873 <td>1</td>
2874 <td>0</td>
2875 </tr>
2876 <tr>
2877 <td>1</td>
2878 <td>0</td>
2879 <td>0</td>
2880 </tr>
2881 <tr>
2882 <td>1</td>
2883 <td>1</td>
2884 <td>1</td>
2885 </tr>
2886 </tbody>
2887</table>
2888</div>
2889<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2890<pre>
2891 &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]2892 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2893 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2894</pre>
2895</div>
2896<!-- _______________________________________________________________________ -->
2897<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2898<div class="doc_text">
2899<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2900<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]2901</pre>
2902<h5>Overview:</h5>
2903<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2904or of its two operands.</p>
2905<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2906
2907<p>The two arguments to the '<tt>or</tt>' instruction must be
2908<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2909values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2910<h5>Semantics:</h5>
2911<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2912<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2913<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2914<table border="1" cellspacing="0" cellpadding="4">
2915 <tbody>
2916 <tr>
2917 <td>In0</td>
2918 <td>In1</td>
2919 <td>Out</td>
2920 </tr>
2921 <tr>
2922 <td>0</td>
2923 <td>0</td>
2924 <td>0</td>
2925 </tr>
2926 <tr>
2927 <td>0</td>
2928 <td>1</td>
2929 <td>1</td>
2930 </tr>
2931 <tr>
2932 <td>1</td>
2933 <td>0</td>
2934 <td>1</td>
2935 </tr>
2936 <tr>
2937 <td>1</td>
2938 <td>1</td>
2939 <td>1</td>
2940 </tr>
2941 </tbody>
2942</table>
2943</div>
2944<h5>Example:</h5>
2945<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2946 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2947 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2948</pre>
2949</div>
2950<!-- _______________________________________________________________________ -->
2951<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2952Instruction</a> </div>
2953<div class="doc_text">
2954<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2955<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]2956</pre>
2957<h5>Overview:</h5>
2958<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2959or of its two operands. The <tt>xor</tt> is used to implement the
2960"one's complement" operation, which is the "~" operator in C.</p>
2961<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2962<p>The two arguments to the '<tt>xor</tt>' instruction must be
2963<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2964values. Both arguments must have identical types.</p>
2965
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2966<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2968<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2969<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2970<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2971<table border="1" cellspacing="0" cellpadding="4">
2972 <tbody>
2973 <tr>
2974 <td>In0</td>
2975 <td>In1</td>
2976 <td>Out</td>
2977 </tr>
2978 <tr>
2979 <td>0</td>
2980 <td>0</td>
2981 <td>0</td>
2982 </tr>
2983 <tr>
2984 <td>0</td>
2985 <td>1</td>
2986 <td>1</td>
2987 </tr>
2988 <tr>
2989 <td>1</td>
2990 <td>0</td>
2991 <td>1</td>
2992 </tr>
2993 <tr>
2994 <td>1</td>
2995 <td>1</td>
2996 <td>0</td>
2997 </tr>
2998 </tbody>
2999</table>
3000</div>
3001<p> </p>
3002<h5>Example:</h5>
3003<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3004 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3005 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3006 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3007</pre>
3008</div>
3009
3010<!-- ======================================================================= -->
3011<div class="doc_subsection">
3012 <a name="vectorops">Vector Operations</a>
3013</div>
3014
3015<div class="doc_text">
3016
3017<p>LLVM supports several instructions to represent vector operations in a
3018target-independent manner. These instructions cover the element-access and
3019vector-specific operations needed to process vectors effectively. While LLVM
3020does directly support these vector operations, many sophisticated algorithms
3021will want to use target-specific intrinsics to take full advantage of a specific
3022target.</p>
3023
3024</div>
3025
3026<!-- _______________________________________________________________________ -->
3027<div class="doc_subsubsection">
3028 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3029</div>
3030
3031<div class="doc_text">
3032
3033<h5>Syntax:</h5>
3034
3035<pre>
3036 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3037</pre>
3038
3039<h5>Overview:</h5>
3040
3041<p>
3042The '<tt>extractelement</tt>' instruction extracts a single scalar
3043element from a vector at a specified index.
3044</p>
3045
3046
3047<h5>Arguments:</h5>
3048
3049<p>
3050The first operand of an '<tt>extractelement</tt>' instruction is a
3051value of <a href="#t_vector">vector</a> type. The second operand is
3052an index indicating the position from which to extract the element.
3053The index may be a variable.</p>
3054
3055<h5>Semantics:</h5>
3056
3057<p>
3058The result is a scalar of the same type as the element type of
3059<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3060<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3061results are undefined.
3062</p>
3063
3064<h5>Example:</h5>
3065
3066<pre>
3067 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3068</pre>
3069</div>
3070
3071
3072<!-- _______________________________________________________________________ -->
3073<div class="doc_subsubsection">
3074 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3075</div>
3076
3077<div class="doc_text">
3078
3079<h5>Syntax:</h5>
3080
3081<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3082 &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]3083</pre>
3084
3085<h5>Overview:</h5>
3086
3087<p>
3088The '<tt>insertelement</tt>' instruction inserts a scalar
3089element into a vector at a specified index.
3090</p>
3091
3092
3093<h5>Arguments:</h5>
3094
3095<p>
3096The first operand of an '<tt>insertelement</tt>' instruction is a
3097value of <a href="#t_vector">vector</a> type. The second operand is a
3098scalar value whose type must equal the element type of the first
3099operand. The third operand is an index indicating the position at
3100which to insert the value. The index may be a variable.</p>
3101
3102<h5>Semantics:</h5>
3103
3104<p>
3105The result is a vector of the same type as <tt>val</tt>. Its
3106element values are those of <tt>val</tt> except at position
3107<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3108exceeds the length of <tt>val</tt>, the results are undefined.
3109</p>
3110
3111<h5>Example:</h5>
3112
3113<pre>
3114 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3115</pre>
3116</div>
3117
3118<!-- _______________________________________________________________________ -->
3119<div class="doc_subsubsection">
3120 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3121</div>
3122
3123<div class="doc_text">
3124
3125<h5>Syntax:</h5>
3126
3127<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3128 &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]3129</pre>
3130
3131<h5>Overview:</h5>
3132
3133<p>
3134The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3135from two input vectors, returning a vector with the same element type as
3136the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137</p>
3138
3139<h5>Arguments:</h5>
3140
3141<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3142The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3143with types that match each other. The third argument is a shuffle mask whose
3144element type is always 'i32'. The result of the instruction is a vector whose
3145length is the same as the shuffle mask and whose element type is the same as
3146the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3147</p>
3148
3149<p>
3150The shuffle mask operand is required to be a constant vector with either
3151constant integer or undef values.
3152</p>
3153
3154<h5>Semantics:</h5>
3155
3156<p>
3157The elements of the two input vectors are numbered from left to right across
3158both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3159the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3160gets. The element selector may be undef (meaning "don't care") and the second
3161operand may be undef if performing a shuffle from only one vector.
3162</p>
3163
3164<h5>Example:</h5>
3165
3166<pre>
3167 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3168 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3169 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3170 &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]3171 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3172 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3173 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3174 &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]3175</pre>
3176</div>
3177
3178
3179<!-- ======================================================================= -->
3180<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3181 <a name="aggregateops">Aggregate Operations</a>
3182</div>
3183
3184<div class="doc_text">
3185
3186<p>LLVM supports several instructions for working with aggregate values.
3187</p>
3188
3189</div>
3190
3191<!-- _______________________________________________________________________ -->
3192<div class="doc_subsubsection">
3193 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3194</div>
3195
3196<div class="doc_text">
3197
3198<h5>Syntax:</h5>
3199
3200<pre>
3201 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3202</pre>
3203
3204<h5>Overview:</h5>
3205
3206<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3207The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3208or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3209</p>
3210
3211
3212<h5>Arguments:</h5>
3213
3214<p>
3215The first operand of an '<tt>extractvalue</tt>' instruction is a
3216value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3217type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3218in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3219'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3220</p>
3221
3222<h5>Semantics:</h5>
3223
3224<p>
3225The result is the value at the position in the aggregate specified by
3226the index operands.
3227</p>
3228
3229<h5>Example:</h5>
3230
3231<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3232 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3233</pre>
3234</div>
3235
3236
3237<!-- _______________________________________________________________________ -->
3238<div class="doc_subsubsection">
3239 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3240</div>
3241
3242<div class="doc_text">
3243
3244<h5>Syntax:</h5>
3245
3246<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3247 &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]3248</pre>
3249
3250<h5>Overview:</h5>
3251
3252<p>
3253The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3254into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3255</p>
3256
3257
3258<h5>Arguments:</h5>
3259
3260<p>
3261The first operand of an '<tt>insertvalue</tt>' instruction is a
3262value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3263The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3264The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3265indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3266indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3267'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3268The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3269by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3270</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3271
3272<h5>Semantics:</h5>
3273
3274<p>
3275The result is an aggregate of the same type as <tt>val</tt>. Its
3276value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3277specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3278</p>
3279
3280<h5>Example:</h5>
3281
3282<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3283 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3284</pre>
3285</div>
3286
3287
3288<!-- ======================================================================= -->
3289<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3290 <a name="memoryops">Memory Access and Addressing Operations</a>
3291</div>
3292
3293<div class="doc_text">
3294
3295<p>A key design point of an SSA-based representation is how it
3296represents memory. In LLVM, no memory locations are in SSA form, which
3297makes things very simple. This section describes how to read, write,
3298allocate, and free memory in LLVM.</p>
3299
3300</div>
3301
3302<!-- _______________________________________________________________________ -->
3303<div class="doc_subsubsection">
3304 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3305</div>
3306
3307<div class="doc_text">
3308
3309<h5>Syntax:</h5>
3310
3311<pre>
3312 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3313</pre>
3314
3315<h5>Overview:</h5>
3316
3317<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3318heap and returns a pointer to it. The object is always allocated in the generic
3319address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3320
3321<h5>Arguments:</h5>
3322
3323<p>The '<tt>malloc</tt>' instruction allocates
3324<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3325bytes of memory from the operating system and returns a pointer of the
3326appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3327number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3328If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3329be aligned to at least that boundary. If not specified, or if zero, the target can
3330choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3331
3332<p>'<tt>type</tt>' must be a sized type.</p>
3333
3334<h5>Semantics:</h5>
3335
3336<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3337a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3338result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3339
3340<h5>Example:</h5>
3341
3342<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3343 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3344
3345 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3346 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3347 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3348 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3349 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3350</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3351
3352<p>Note that the code generator does not yet respect the
3353 alignment value.</p>
3354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3355</div>
3356
3357<!-- _______________________________________________________________________ -->
3358<div class="doc_subsubsection">
3359 <a name="i_free">'<tt>free</tt>' Instruction</a>
3360</div>
3361
3362<div class="doc_text">
3363
3364<h5>Syntax:</h5>
3365
3366<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3367 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3368</pre>
3369
3370<h5>Overview:</h5>
3371
3372<p>The '<tt>free</tt>' instruction returns memory back to the unused
3373memory heap to be reallocated in the future.</p>
3374
3375<h5>Arguments:</h5>
3376
3377<p>'<tt>value</tt>' shall be a pointer value that points to a value
3378that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3379instruction.</p>
3380
3381<h5>Semantics:</h5>
3382
3383<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3384after this instruction executes. If the pointer is null, the operation
3385is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3386
3387<h5>Example:</h5>
3388
3389<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3390 %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]3391 free [4 x i8]* %array
3392</pre>
3393</div>
3394
3395<!-- _______________________________________________________________________ -->
3396<div class="doc_subsubsection">
3397 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3398</div>
3399
3400<div class="doc_text">
3401
3402<h5>Syntax:</h5>
3403
3404<pre>
3405 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3406</pre>
3407
3408<h5>Overview:</h5>
3409
3410<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3411currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3412returns to its caller. The object is always allocated in the generic address
3413space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3414
3415<h5>Arguments:</h5>
3416
3417<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3418bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3419appropriate type to the program. If "NumElements" is specified, it is the
3420number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3421If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3422to be aligned to at least that boundary. If not specified, or if zero, the target
3423can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3424
3425<p>'<tt>type</tt>' may be any sized type.</p>
3426
3427<h5>Semantics:</h5>
3428
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3429<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3430there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3431memory is automatically released when the function returns. The '<tt>alloca</tt>'
3432instruction is commonly used to represent automatic variables that must
3433have an address available. When the function returns (either with the <tt><a
3434 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]3435instructions), the memory is reclaimed. Allocating zero bytes
3436is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3437
3438<h5>Example:</h5>
3439
3440<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3441 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3442 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3443 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3444 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3445</pre>
3446</div>
3447
3448<!-- _______________________________________________________________________ -->
3449<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3450Instruction</a> </div>
3451<div class="doc_text">
3452<h5>Syntax:</h5>
3453<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>
3454<h5>Overview:</h5>
3455<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3456<h5>Arguments:</h5>
3457<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3458address from which to load. The pointer must point to a <a
3459 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3460marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3461the number or order of execution of this <tt>load</tt> with other
3462volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3463instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3464<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3465The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3466(that is, the alignment of the memory address). A value of 0 or an
3467omitted "align" argument means that the operation has the preferential
3468alignment for the target. It is the responsibility of the code emitter
3469to ensure that the alignment information is correct. Overestimating
3470the alignment results in an undefined behavior. Underestimating the
3471alignment may produce less efficient code. An alignment of 1 is always
3472safe.
3473</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3474<h5>Semantics:</h5>
3475<p>The location of memory pointed to is loaded.</p>
3476<h5>Examples:</h5>
3477<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3478 <a
3479 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3480 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3481</pre>
3482</div>
3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3485Instruction</a> </div>
3486<div class="doc_text">
3487<h5>Syntax:</h5>
3488<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3489 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3490</pre>
3491<h5>Overview:</h5>
3492<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3493<h5>Arguments:</h5>
3494<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3495to 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]3496operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3497of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3498operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3499optimizer is not allowed to modify the number or order of execution of
3500this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3501 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3502<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3503The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3504(that is, the alignment of the memory address). A value of 0 or an
3505omitted "align" argument means that the operation has the preferential
3506alignment for the target. It is the responsibility of the code emitter
3507to ensure that the alignment information is correct. Overestimating
3508the alignment results in an undefined behavior. Underestimating the
3509alignment may produce less efficient code. An alignment of 1 is always
3510safe.
3511</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3512<h5>Semantics:</h5>
3513<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3514at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3515<h5>Example:</h5>
3516<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3517 store i32 3, i32* %ptr <i>; yields {void}</i>
3518 %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]3519</pre>
3520</div>
3521
3522<!-- _______________________________________________________________________ -->
3523<div class="doc_subsubsection">
3524 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3525</div>
3526
3527<div class="doc_text">
3528<h5>Syntax:</h5>
3529<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3530 &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]3531</pre>
3532
3533<h5>Overview:</h5>
3534
3535<p>
3536The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3537subelement of an aggregate data structure. It performs address calculation only
3538and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3539
3540<h5>Arguments:</h5>
3541
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3542<p>The first argument is always a pointer, and forms the basis of the
3543calculation. The remaining arguments are indices, that indicate which of the
3544elements of the aggregate object are indexed. The interpretation of each index
3545is dependent on the type being indexed into. The first index always indexes the
3546pointer value given as the first argument, the second index indexes a value of
3547the type pointed to (not necessarily the value directly pointed to, since the
3548first index can be non-zero), etc. The first type indexed into must be a pointer
3549value, subsequent types can be arrays, vectors and structs. Note that subsequent
3550types being indexed into can never be pointers, since that would require loading
3551the pointer before continuing calculation.</p>
3552
3553<p>The type of each index argument depends on the type it is indexing into.
3554When indexing into a (packed) structure, only <tt>i32</tt> integer
3555<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3556only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3557will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3558
3559<p>For example, let's consider a C code fragment and how it gets
3560compiled to LLVM:</p>
3561
3562<div class="doc_code">
3563<pre>
3564struct RT {
3565 char A;
3566 int B[10][20];
3567 char C;
3568};
3569struct ST {
3570 int X;
3571 double Y;
3572 struct RT Z;
3573};
3574
3575int *foo(struct ST *s) {
3576 return &amp;s[1].Z.B[5][13];
3577}
3578</pre>
3579</div>
3580
3581<p>The LLVM code generated by the GCC frontend is:</p>
3582
3583<div class="doc_code">
3584<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3585%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3586%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3587
3588define i32* %foo(%ST* %s) {
3589entry:
3590 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3591 ret i32* %reg
3592}
3593</pre>
3594</div>
3595
3596<h5>Semantics:</h5>
3597
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3598<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3599type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3600}</tt>' type, a structure. The second index indexes into the third element of
3601the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3602i8 }</tt>' type, another structure. The third index indexes into the second
3603element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3604array. The two dimensions of the array are subscripted into, yielding an
3605'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3606to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3607
3608<p>Note that it is perfectly legal to index partially through a
3609structure, returning a pointer to an inner element. Because of this,
3610the LLVM code for the given testcase is equivalent to:</p>
3611
3612<pre>
3613 define i32* %foo(%ST* %s) {
3614 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3615 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3616 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3617 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3618 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3619 ret i32* %t5
3620 }
3621</pre>
3622
3623<p>Note that it is undefined to access an array out of bounds: array and
3624pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3625The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3626defined to be accessible as variable length arrays, which requires access
3627beyond the zero'th element.</p>
3628
3629<p>The getelementptr instruction is often confusing. For some more insight
3630into how it works, see <a href="GetElementPtr.html">the getelementptr
3631FAQ</a>.</p>
3632
3633<h5>Example:</h5>
3634
3635<pre>
3636 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3637 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3638 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3639 %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]3640 <i>; yields i8*:eptr</i>
3641 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3642</pre>
3643</div>
3644
3645<!-- ======================================================================= -->
3646<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3647</div>
3648<div class="doc_text">
3649<p>The instructions in this category are the conversion instructions (casting)
3650which all take a single operand and a type. They perform various bit conversions
3651on the operand.</p>
3652</div>
3653
3654<!-- _______________________________________________________________________ -->
3655<div class="doc_subsubsection">
3656 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3657</div>
3658<div class="doc_text">
3659
3660<h5>Syntax:</h5>
3661<pre>
3662 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3663</pre>
3664
3665<h5>Overview:</h5>
3666<p>
3667The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3668</p>
3669
3670<h5>Arguments:</h5>
3671<p>
3672The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3673be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3674and type of the result, which must be an <a href="#t_integer">integer</a>
3675type. The bit size of <tt>value</tt> must be larger than the bit size of
3676<tt>ty2</tt>. Equal sized types are not allowed.</p>
3677
3678<h5>Semantics:</h5>
3679<p>
3680The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3681and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3682larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3683It will always truncate bits.</p>
3684
3685<h5>Example:</h5>
3686<pre>
3687 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3688 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3689 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3690</pre>
3691</div>
3692
3693<!-- _______________________________________________________________________ -->
3694<div class="doc_subsubsection">
3695 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3696</div>
3697<div class="doc_text">
3698
3699<h5>Syntax:</h5>
3700<pre>
3701 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3702</pre>
3703
3704<h5>Overview:</h5>
3705<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3706<tt>ty2</tt>.</p>
3707
3708
3709<h5>Arguments:</h5>
3710<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3711<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3712also be of <a href="#t_integer">integer</a> type. The bit size of the
3713<tt>value</tt> must be smaller than the bit size of the destination type,
3714<tt>ty2</tt>.</p>
3715
3716<h5>Semantics:</h5>
3717<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3718bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3719
3720<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3721
3722<h5>Example:</h5>
3723<pre>
3724 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3725 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3726</pre>
3727</div>
3728
3729<!-- _______________________________________________________________________ -->
3730<div class="doc_subsubsection">
3731 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3732</div>
3733<div class="doc_text">
3734
3735<h5>Syntax:</h5>
3736<pre>
3737 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3738</pre>
3739
3740<h5>Overview:</h5>
3741<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3742
3743<h5>Arguments:</h5>
3744<p>
3745The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3746<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3747also be of <a href="#t_integer">integer</a> type. The bit size of the
3748<tt>value</tt> must be smaller than the bit size of the destination type,
3749<tt>ty2</tt>.</p>
3750
3751<h5>Semantics:</h5>
3752<p>
3753The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3754bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3755the type <tt>ty2</tt>.</p>
3756
3757<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3758
3759<h5>Example:</h5>
3760<pre>
3761 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3762 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3763</pre>
3764</div>
3765
3766<!-- _______________________________________________________________________ -->
3767<div class="doc_subsubsection">
3768 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3769</div>
3770
3771<div class="doc_text">
3772
3773<h5>Syntax:</h5>
3774
3775<pre>
3776 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3777</pre>
3778
3779<h5>Overview:</h5>
3780<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3781<tt>ty2</tt>.</p>
3782
3783
3784<h5>Arguments:</h5>
3785<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3786 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3787cast it to. The size of <tt>value</tt> must be larger than the size of
3788<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3789<i>no-op cast</i>.</p>
3790
3791<h5>Semantics:</h5>
3792<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3793<a href="#t_floating">floating point</a> type to a smaller
3794<a href="#t_floating">floating point</a> type. If the value cannot fit within
3795the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3796
3797<h5>Example:</h5>
3798<pre>
3799 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3800 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3801</pre>
3802</div>
3803
3804<!-- _______________________________________________________________________ -->
3805<div class="doc_subsubsection">
3806 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3807</div>
3808<div class="doc_text">
3809
3810<h5>Syntax:</h5>
3811<pre>
3812 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3813</pre>
3814
3815<h5>Overview:</h5>
3816<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3817floating point value.</p>
3818
3819<h5>Arguments:</h5>
3820<p>The '<tt>fpext</tt>' instruction takes a
3821<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3822and a <a href="#t_floating">floating point</a> type to cast it to. The source
3823type must be smaller than the destination type.</p>
3824
3825<h5>Semantics:</h5>
3826<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3827<a href="#t_floating">floating point</a> type to a larger
3828<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3829used to make a <i>no-op cast</i> because it always changes bits. Use
3830<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3831
3832<h5>Example:</h5>
3833<pre>
3834 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3835 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3836</pre>
3837</div>
3838
3839<!-- _______________________________________________________________________ -->
3840<div class="doc_subsubsection">
3841 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3842</div>
3843<div class="doc_text">
3844
3845<h5>Syntax:</h5>
3846<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3847 &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]3848</pre>
3849
3850<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3851<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3852unsigned integer equivalent of type <tt>ty2</tt>.
3853</p>
3854
3855<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3856<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]3857scalar or vector <a href="#t_floating">floating point</a> value, and a type
3858to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3859type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3860vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3861
3862<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3863<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3864<a href="#t_floating">floating point</a> operand into the nearest (rounding
3865towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3866the results are undefined.</p>
3867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3868<h5>Example:</h5>
3869<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3870 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3871 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3872 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3873</pre>
3874</div>
3875
3876<!-- _______________________________________________________________________ -->
3877<div class="doc_subsubsection">
3878 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3879</div>
3880<div class="doc_text">
3881
3882<h5>Syntax:</h5>
3883<pre>
3884 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3885</pre>
3886
3887<h5>Overview:</h5>
3888<p>The '<tt>fptosi</tt>' instruction converts
3889<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3890</p>
3891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3892<h5>Arguments:</h5>
3893<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]3894scalar or vector <a href="#t_floating">floating point</a> value, and a type
3895to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3896type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3897vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3898
3899<h5>Semantics:</h5>
3900<p>The '<tt>fptosi</tt>' instruction converts its
3901<a href="#t_floating">floating point</a> operand into the nearest (rounding
3902towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3903the results are undefined.</p>
3904
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3905<h5>Example:</h5>
3906<pre>
3907 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3908 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3910</pre>
3911</div>
3912
3913<!-- _______________________________________________________________________ -->
3914<div class="doc_subsubsection">
3915 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3916</div>
3917<div class="doc_text">
3918
3919<h5>Syntax:</h5>
3920<pre>
3921 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3922</pre>
3923
3924<h5>Overview:</h5>
3925<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3926integer and converts that value to the <tt>ty2</tt> type.</p>
3927
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3928<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3929<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3930scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3931to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3932type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3933floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3934
3935<h5>Semantics:</h5>
3936<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3937integer quantity and converts it to the corresponding floating point value. If
3938the value cannot fit in the floating point value, the results are undefined.</p>
3939
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3940<h5>Example:</h5>
3941<pre>
3942 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3943 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944</pre>
3945</div>
3946
3947<!-- _______________________________________________________________________ -->
3948<div class="doc_subsubsection">
3949 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3950</div>
3951<div class="doc_text">
3952
3953<h5>Syntax:</h5>
3954<pre>
3955 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3956</pre>
3957
3958<h5>Overview:</h5>
3959<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3960integer and converts that value to the <tt>ty2</tt> type.</p>
3961
3962<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3963<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3964scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3965to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3966type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3967floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3968
3969<h5>Semantics:</h5>
3970<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3971integer quantity and converts it to the corresponding floating point value. If
3972the value cannot fit in the floating point value, the results are undefined.</p>
3973
3974<h5>Example:</h5>
3975<pre>
3976 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3977 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978</pre>
3979</div>
3980
3981<!-- _______________________________________________________________________ -->
3982<div class="doc_subsubsection">
3983 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3984</div>
3985<div class="doc_text">
3986
3987<h5>Syntax:</h5>
3988<pre>
3989 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3990</pre>
3991
3992<h5>Overview:</h5>
3993<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3994the integer type <tt>ty2</tt>.</p>
3995
3996<h5>Arguments:</h5>
3997<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3998must 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]3999<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]4000
4001<h5>Semantics:</h5>
4002<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4003<tt>ty2</tt> by interpreting the pointer value as an integer and either
4004truncating or zero extending that value to the size of the integer type. If
4005<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4006<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4007are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4008change.</p>
4009
4010<h5>Example:</h5>
4011<pre>
4012 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4013 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4014</pre>
4015</div>
4016
4017<!-- _______________________________________________________________________ -->
4018<div class="doc_subsubsection">
4019 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4020</div>
4021<div class="doc_text">
4022
4023<h5>Syntax:</h5>
4024<pre>
4025 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4026</pre>
4027
4028<h5>Overview:</h5>
4029<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4030a pointer type, <tt>ty2</tt>.</p>
4031
4032<h5>Arguments:</h5>
4033<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4034value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4035<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4036
4037<h5>Semantics:</h5>
4038<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4039<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4040the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4041size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4042the size of a pointer then a zero extension is done. If they are the same size,
4043nothing is done (<i>no-op cast</i>).</p>
4044
4045<h5>Example:</h5>
4046<pre>
4047 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4048 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4049 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4050</pre>
4051</div>
4052
4053<!-- _______________________________________________________________________ -->
4054<div class="doc_subsubsection">
4055 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4056</div>
4057<div class="doc_text">
4058
4059<h5>Syntax:</h5>
4060<pre>
4061 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4062</pre>
4063
4064<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4066<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4067<tt>ty2</tt> without changing any bits.</p>
4068
4069<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4070
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4071<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4072a non-aggregate first class value, and a type to cast it to, which must also be
4073a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4074<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4075and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4076type is a pointer, the destination type must also be a pointer. This
4077instruction supports bitwise conversion of vectors to integers and to vectors
4078of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4079
4080<h5>Semantics:</h5>
4081<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4082<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4083this conversion. The conversion is done as if the <tt>value</tt> had been
4084stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4085converted to other pointer types with this instruction. To convert pointers to
4086other types, use the <a href="#i_inttoptr">inttoptr</a> or
4087<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4088
4089<h5>Example:</h5>
4090<pre>
4091 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4092 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4093 %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]4094</pre>
4095</div>
4096
4097<!-- ======================================================================= -->
4098<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4099<div class="doc_text">
4100<p>The instructions in this category are the "miscellaneous"
4101instructions, which defy better classification.</p>
4102</div>
4103
4104<!-- _______________________________________________________________________ -->
4105<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4106</div>
4107<div class="doc_text">
4108<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4109<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]4110</pre>
4111<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4112<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4113a vector of boolean values based on comparison
4114of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4115<h5>Arguments:</h5>
4116<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4117the condition code indicating the kind of comparison to perform. It is not
4118a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4119</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120<ol>
4121 <li><tt>eq</tt>: equal</li>
4122 <li><tt>ne</tt>: not equal </li>
4123 <li><tt>ugt</tt>: unsigned greater than</li>
4124 <li><tt>uge</tt>: unsigned greater or equal</li>
4125 <li><tt>ult</tt>: unsigned less than</li>
4126 <li><tt>ule</tt>: unsigned less or equal</li>
4127 <li><tt>sgt</tt>: signed greater than</li>
4128 <li><tt>sge</tt>: signed greater or equal</li>
4129 <li><tt>slt</tt>: signed less than</li>
4130 <li><tt>sle</tt>: signed less or equal</li>
4131</ol>
4132<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4133<a href="#t_pointer">pointer</a>
4134or integer <a href="#t_vector">vector</a> typed.
4135They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4136<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4137<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]4138the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4139yields 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]4140</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4141<ol>
4142 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4143 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4144 </li>
4145 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4146 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4147 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4148 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4149 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4150 <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]4151 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4152 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4153 <li><tt>ule</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 less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4155 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4156 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4157 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4158 <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]4159 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4160 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4161 <li><tt>sle</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 less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4163</ol>
4164<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4165values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4166<p>If the operands are integer vectors, then they are compared
4167element by element. The result is an <tt>i1</tt> vector with
4168the same number of elements as the values being compared.
4169Otherwise, the result is an <tt>i1</tt>.
4170</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4171
4172<h5>Example:</h5>
4173<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4174 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4175 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4176 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4177 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4178 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4179</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4180
4181<p>Note that the code generator does not yet support vector types with
4182 the <tt>icmp</tt> instruction.</p>
4183
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4184</div>
4185
4186<!-- _______________________________________________________________________ -->
4187<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4188</div>
4189<div class="doc_text">
4190<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4191<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]4192</pre>
4193<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4194<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4195or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4196of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4197<p>
4198If the operands are floating point scalars, then the result
4199type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4200</p>
4201<p>If the operands are floating point vectors, then the result type
4202is a vector of boolean with the same number of elements as the
4203operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4204<h5>Arguments:</h5>
4205<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4206the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4207a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4208<ol>
4209 <li><tt>false</tt>: no comparison, always returns false</li>
4210 <li><tt>oeq</tt>: ordered and equal</li>
4211 <li><tt>ogt</tt>: ordered and greater than </li>
4212 <li><tt>oge</tt>: ordered and greater than or equal</li>
4213 <li><tt>olt</tt>: ordered and less than </li>
4214 <li><tt>ole</tt>: ordered and less than or equal</li>
4215 <li><tt>one</tt>: ordered and not equal</li>
4216 <li><tt>ord</tt>: ordered (no nans)</li>
4217 <li><tt>ueq</tt>: unordered or equal</li>
4218 <li><tt>ugt</tt>: unordered or greater than </li>
4219 <li><tt>uge</tt>: unordered or greater than or equal</li>
4220 <li><tt>ult</tt>: unordered or less than </li>
4221 <li><tt>ule</tt>: unordered or less than or equal</li>
4222 <li><tt>une</tt>: unordered or not equal</li>
4223 <li><tt>uno</tt>: unordered (either nans)</li>
4224 <li><tt>true</tt>: no comparison, always returns true</li>
4225</ol>
4226<p><i>Ordered</i> means that neither operand is a QNAN while
4227<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4228<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4229either a <a href="#t_floating">floating point</a> type
4230or a <a href="#t_vector">vector</a> of floating point type.
4231They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4232<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4233<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4234according to the condition code given as <tt>cond</tt>.
4235If the operands are vectors, then the vectors are compared
4236element by element.
4237Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4238always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4239<ol>
4240 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4241 <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]4242 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4243 <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]4244 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245 <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]4246 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4247 <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]4248 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249 <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]4250 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4251 <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]4252 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4254 <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]4255 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4256 <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]4257 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258 <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]4259 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260 <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]4261 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4262 <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]4263 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4264 <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]4265 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4266 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4267 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4268</ol>
4269
4270<h5>Example:</h5>
4271<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]4272 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4273 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4274 &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]4275</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4276
4277<p>Note that the code generator does not yet support vector types with
4278 the <tt>fcmp</tt> instruction.</p>
4279
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4280</div>
4281
4282<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4283<div class="doc_subsubsection">
4284 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4285</div>
4286<div class="doc_text">
4287<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4288<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]4289</pre>
4290<h5>Overview:</h5>
4291<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4292element-wise comparison of its two integer vector operands.</p>
4293<h5>Arguments:</h5>
4294<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4295the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4296a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4297<ol>
4298 <li><tt>eq</tt>: equal</li>
4299 <li><tt>ne</tt>: not equal </li>
4300 <li><tt>ugt</tt>: unsigned greater than</li>
4301 <li><tt>uge</tt>: unsigned greater or equal</li>
4302 <li><tt>ult</tt>: unsigned less than</li>
4303 <li><tt>ule</tt>: unsigned less or equal</li>
4304 <li><tt>sgt</tt>: signed greater than</li>
4305 <li><tt>sge</tt>: signed greater or equal</li>
4306 <li><tt>slt</tt>: signed less than</li>
4307 <li><tt>sle</tt>: signed less or equal</li>
4308</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4309<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4310<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4311<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4312<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4313according to the condition code given as <tt>cond</tt>. The comparison yields a
4314<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4315identical type as the values being compared. The most significant bit in each
4316element is 1 if the element-wise comparison evaluates to true, and is 0
4317otherwise. All other bits of the result are undefined. The condition codes
4318are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4319instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4320
4321<h5>Example:</h5>
4322<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4323 &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>
4324 &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]4325</pre>
4326</div>
4327
4328<!-- _______________________________________________________________________ -->
4329<div class="doc_subsubsection">
4330 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4331</div>
4332<div class="doc_text">
4333<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4334<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]4335<h5>Overview:</h5>
4336<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4337element-wise comparison of its two floating point vector operands. The output
4338elements have the same width as the input elements.</p>
4339<h5>Arguments:</h5>
4340<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4341the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4342a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4343<ol>
4344 <li><tt>false</tt>: no comparison, always returns false</li>
4345 <li><tt>oeq</tt>: ordered and equal</li>
4346 <li><tt>ogt</tt>: ordered and greater than </li>
4347 <li><tt>oge</tt>: ordered and greater than or equal</li>
4348 <li><tt>olt</tt>: ordered and less than </li>
4349 <li><tt>ole</tt>: ordered and less than or equal</li>
4350 <li><tt>one</tt>: ordered and not equal</li>
4351 <li><tt>ord</tt>: ordered (no nans)</li>
4352 <li><tt>ueq</tt>: unordered or equal</li>
4353 <li><tt>ugt</tt>: unordered or greater than </li>
4354 <li><tt>uge</tt>: unordered or greater than or equal</li>
4355 <li><tt>ult</tt>: unordered or less than </li>
4356 <li><tt>ule</tt>: unordered or less than or equal</li>
4357 <li><tt>une</tt>: unordered or not equal</li>
4358 <li><tt>uno</tt>: unordered (either nans)</li>
4359 <li><tt>true</tt>: no comparison, always returns true</li>
4360</ol>
4361<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4362<a href="#t_floating">floating point</a> typed. They must also be identical
4363types.</p>
4364<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4365<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4366according to the condition code given as <tt>cond</tt>. The comparison yields a
4367<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4368an identical number of elements as the values being compared, and each element
4369having identical with to the width of the floating point elements. The most
4370significant bit in each element is 1 if the element-wise comparison evaluates to
4371true, and is 0 otherwise. All other bits of the result are undefined. The
4372condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4373<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4374
4375<h5>Example:</h5>
4376<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4377 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4378 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4379
4380 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4381 &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]4382</pre>
4383</div>
4384
4385<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4386<div class="doc_subsubsection">
4387 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4388</div>
4389
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4390<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4392<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4393
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4395<h5>Overview:</h5>
4396<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4397the SSA graph representing the function.</p>
4398<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4400<p>The type of the incoming values is specified with the first type
4401field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4402as arguments, with one pair for each predecessor basic block of the
4403current block. Only values of <a href="#t_firstclass">first class</a>
4404type may be used as the value arguments to the PHI node. Only labels
4405may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4406
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4407<p>There must be no non-phi instructions between the start of a basic
4408block and the PHI instructions: i.e. PHI instructions must be first in
4409a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4410
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4411<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4412
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4413<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4414specified by the pair corresponding to the predecessor basic block that executed
4415just prior to the current 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>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4418<pre>
4419Loop: ; Infinite loop that counts from 0 on up...
4420 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4421 %nextindvar = add i32 %indvar, 1
4422 br label %Loop
4423</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4424</div>
4425
4426<!-- _______________________________________________________________________ -->
4427<div class="doc_subsubsection">
4428 <a name="i_select">'<tt>select</tt>' Instruction</a>
4429</div>
4430
4431<div class="doc_text">
4432
4433<h5>Syntax:</h5>
4434
4435<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4436 &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>
4437
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4438 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4439</pre>
4440
4441<h5>Overview:</h5>
4442
4443<p>
4444The '<tt>select</tt>' instruction is used to choose one value based on a
4445condition, without branching.
4446</p>
4447
4448
4449<h5>Arguments:</h5>
4450
4451<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4452The '<tt>select</tt>' instruction requires an 'i1' value or
4453a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4454condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4455type. If the val1/val2 are vectors and
4456the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4457individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4458</p>
4459
4460<h5>Semantics:</h5>
4461
4462<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4463If 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]4464value argument; otherwise, it returns the second value argument.
4465</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4466<p>
4467If the condition is a vector of i1, then the value arguments must
4468be vectors of the same size, and the selection is done element
4469by element.
4470</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4471
4472<h5>Example:</h5>
4473
4474<pre>
4475 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4476</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4477
4478<p>Note that the code generator does not yet support conditions
4479 with vector type.</p>
4480
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4481</div>
4482
4483
4484<!-- _______________________________________________________________________ -->
4485<div class="doc_subsubsection">
4486 <a name="i_call">'<tt>call</tt>' Instruction</a>
4487</div>
4488
4489<div class="doc_text">
4490
4491<h5>Syntax:</h5>
4492<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4493 &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]4494</pre>
4495
4496<h5>Overview:</h5>
4497
4498<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4499
4500<h5>Arguments:</h5>
4501
4502<p>This instruction requires several arguments:</p>
4503
4504<ol>
4505 <li>
4506 <p>The optional "tail" marker indicates whether the callee function accesses
4507 any allocas or varargs in the caller. If the "tail" marker is present, the
4508 function call is eligible for tail call optimization. Note that calls may
4509 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4510 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4511 </li>
4512 <li>
4513 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4514 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4515 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4516 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4517
4518 <li>
4519 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4520 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4521 and '<tt>inreg</tt>' attributes are valid here.</p>
4522 </li>
4523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4524 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4525 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4526 the type of the return value. Functions that return no value are marked
4527 <tt><a href="#t_void">void</a></tt>.</p>
4528 </li>
4529 <li>
4530 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4531 value being invoked. The argument types must match the types implied by
4532 this signature. This type can be omitted if the function is not varargs
4533 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4534 </li>
4535 <li>
4536 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4537 be invoked. In most cases, this is a direct function invocation, but
4538 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4539 to function value.</p>
4540 </li>
4541 <li>
4542 <p>'<tt>function args</tt>': argument list whose types match the
4543 function signature argument types. All arguments must be of
4544 <a href="#t_firstclass">first class</a> type. If the function signature
4545 indicates the function accepts a variable number of arguments, the extra
4546 arguments can be specified.</p>
4547 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4548 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4549 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4550 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4551 '<tt>readnone</tt>' attributes are valid here.</p>
4552 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4553</ol>
4554
4555<h5>Semantics:</h5>
4556
4557<p>The '<tt>call</tt>' instruction is used to cause control flow to
4558transfer to a specified function, with its incoming arguments bound to
4559the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4560instruction in the called function, control flow continues with the
4561instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4562function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4563
4564<h5>Example:</h5>
4565
4566<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4567 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4568 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4569 %X = tail call i32 @foo() <i>; yields i32</i>
4570 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4571 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4572
4573 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4574 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4575 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4576 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4577 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4578 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4579</pre>
4580
4581</div>
4582
4583<!-- _______________________________________________________________________ -->
4584<div class="doc_subsubsection">
4585 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4586</div>
4587
4588<div class="doc_text">
4589
4590<h5>Syntax:</h5>
4591
4592<pre>
4593 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4594</pre>
4595
4596<h5>Overview:</h5>
4597
4598<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4599the "variable argument" area of a function call. It is used to implement the
4600<tt>va_arg</tt> macro in C.</p>
4601
4602<h5>Arguments:</h5>
4603
4604<p>This instruction takes a <tt>va_list*</tt> value and the type of
4605the argument. It returns a value of the specified argument type and
4606increments the <tt>va_list</tt> to point to the next argument. The
4607actual type of <tt>va_list</tt> is target specific.</p>
4608
4609<h5>Semantics:</h5>
4610
4611<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4612type from the specified <tt>va_list</tt> and causes the
4613<tt>va_list</tt> to point to the next argument. For more information,
4614see the variable argument handling <a href="#int_varargs">Intrinsic
4615Functions</a>.</p>
4616
4617<p>It is legal for this instruction to be called in a function which does not
4618take a variable number of arguments, for example, the <tt>vfprintf</tt>
4619function.</p>
4620
4621<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4622href="#intrinsics">intrinsic function</a> because it takes a type as an
4623argument.</p>
4624
4625<h5>Example:</h5>
4626
4627<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4628
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4629<p>Note that the code generator does not yet fully support va_arg
4630 on many targets. Also, it does not currently support va_arg with
4631 aggregate types on any target.</p>
4632
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4633</div>
4634
4635<!-- *********************************************************************** -->
4636<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4637<!-- *********************************************************************** -->
4638
4639<div class="doc_text">
4640
4641<p>LLVM supports the notion of an "intrinsic function". These functions have
4642well known names and semantics and are required to follow certain restrictions.
4643Overall, these intrinsics represent an extension mechanism for the LLVM
4644language that does not require changing all of the transformations in LLVM when
4645adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4646
4647<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4648prefix is reserved in LLVM for intrinsic names; thus, function names may not
4649begin with this prefix. Intrinsic functions must always be external functions:
4650you cannot define the body of intrinsic functions. Intrinsic functions may
4651only be used in call or invoke instructions: it is illegal to take the address
4652of an intrinsic function. Additionally, because intrinsic functions are part
4653of the LLVM language, it is required if any are added that they be documented
4654here.</p>
4655
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4656<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4657a family of functions that perform the same operation but on different data
4658types. Because LLVM can represent over 8 million different integer types,
4659overloading is used commonly to allow an intrinsic function to operate on any
4660integer type. One or more of the argument types or the result type can be
4661overloaded to accept any integer type. Argument types may also be defined as
4662exactly matching a previous argument's type or the result type. This allows an
4663intrinsic function which accepts multiple arguments, but needs all of them to
4664be of the same type, to only be overloaded with respect to a single argument or
4665the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4667<p>Overloaded intrinsics will have the names of its overloaded argument types
4668encoded into its function name, each preceded by a period. Only those types
4669which are overloaded result in a name suffix. Arguments whose type is matched
4670against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4671take an integer of any width and returns an integer of exactly the same integer
4672width. This leads to a family of functions such as
4673<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4674Only one type, the return type, is overloaded, and only one type suffix is
4675required. Because the argument's type is matched against the return type, it
4676does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4677
4678<p>To learn how to add an intrinsic function, please see the
4679<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4680</p>
4681
4682</div>
4683
4684<!-- ======================================================================= -->
4685<div class="doc_subsection">
4686 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4687</div>
4688
4689<div class="doc_text">
4690
4691<p>Variable argument support is defined in LLVM with the <a
4692 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4693intrinsic functions. These functions are related to the similarly
4694named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4695
4696<p>All of these functions operate on arguments that use a
4697target-specific value type "<tt>va_list</tt>". The LLVM assembly
4698language reference manual does not define what this type is, so all
4699transformations should be prepared to handle these functions regardless of
4700the type used.</p>
4701
4702<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4703instruction and the variable argument handling intrinsic functions are
4704used.</p>
4705
4706<div class="doc_code">
4707<pre>
4708define i32 @test(i32 %X, ...) {
4709 ; Initialize variable argument processing
4710 %ap = alloca i8*
4711 %ap2 = bitcast i8** %ap to i8*
4712 call void @llvm.va_start(i8* %ap2)
4713
4714 ; Read a single integer argument
4715 %tmp = va_arg i8** %ap, i32
4716
4717 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4718 %aq = alloca i8*
4719 %aq2 = bitcast i8** %aq to i8*
4720 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4721 call void @llvm.va_end(i8* %aq2)
4722
4723 ; Stop processing of arguments.
4724 call void @llvm.va_end(i8* %ap2)
4725 ret i32 %tmp
4726}
4727
4728declare void @llvm.va_start(i8*)
4729declare void @llvm.va_copy(i8*, i8*)
4730declare void @llvm.va_end(i8*)
4731</pre>
4732</div>
4733
4734</div>
4735
4736<!-- _______________________________________________________________________ -->
4737<div class="doc_subsubsection">
4738 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4739</div>
4740
4741
4742<div class="doc_text">
4743<h5>Syntax:</h5>
4744<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4745<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4746<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4747<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4748href="#i_va_arg">va_arg</a></tt>.</p>
4749
4750<h5>Arguments:</h5>
4751
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4752<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]4753
4754<h5>Semantics:</h5>
4755
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4756<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]4757macro available in C. In a target-dependent way, it initializes the
4758<tt>va_list</tt> element to which the argument points, so that the next call to
4759<tt>va_arg</tt> will produce the first variable argument passed to the function.
4760Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4761last argument of the function as the compiler can figure that out.</p>
4762
4763</div>
4764
4765<!-- _______________________________________________________________________ -->
4766<div class="doc_subsubsection">
4767 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4768</div>
4769
4770<div class="doc_text">
4771<h5>Syntax:</h5>
4772<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4773<h5>Overview:</h5>
4774
4775<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4776which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4777or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4778
4779<h5>Arguments:</h5>
4780
4781<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4782
4783<h5>Semantics:</h5>
4784
4785<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4786macro available in C. In a target-dependent way, it destroys the
4787<tt>va_list</tt> element to which the argument points. Calls to <a
4788href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4789<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4790<tt>llvm.va_end</tt>.</p>
4791
4792</div>
4793
4794<!-- _______________________________________________________________________ -->
4795<div class="doc_subsubsection">
4796 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4797</div>
4798
4799<div class="doc_text">
4800
4801<h5>Syntax:</h5>
4802
4803<pre>
4804 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4805</pre>
4806
4807<h5>Overview:</h5>
4808
4809<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4810from the source argument list to the destination argument list.</p>
4811
4812<h5>Arguments:</h5>
4813
4814<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4815The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4816
4817
4818<h5>Semantics:</h5>
4819
4820<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4821macro available in C. In a target-dependent way, it copies the source
4822<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4823intrinsic is necessary because the <tt><a href="#int_va_start">
4824llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4825example, memory allocation.</p>
4826
4827</div>
4828
4829<!-- ======================================================================= -->
4830<div class="doc_subsection">
4831 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4832</div>
4833
4834<div class="doc_text">
4835
4836<p>
4837LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4838Collection</a> (GC) requires the implementation and generation of these
4839intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4840These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4841stack</a>, as well as garbage collector implementations that require <a
4842href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4843Front-ends for type-safe garbage collected languages should generate these
4844intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4845href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4846</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4847
4848<p>The garbage collection intrinsics only operate on objects in the generic
4849 address space (address space zero).</p>
4850
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4851</div>
4852
4853<!-- _______________________________________________________________________ -->
4854<div class="doc_subsubsection">
4855 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4856</div>
4857
4858<div class="doc_text">
4859
4860<h5>Syntax:</h5>
4861
4862<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4863 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4864</pre>
4865
4866<h5>Overview:</h5>
4867
4868<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4869the code generator, and allows some metadata to be associated with it.</p>
4870
4871<h5>Arguments:</h5>
4872
4873<p>The first argument specifies the address of a stack object that contains the
4874root pointer. The second pointer (which must be either a constant or a global
4875value address) contains the meta-data to be associated with the root.</p>
4876
4877<h5>Semantics:</h5>
4878
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4879<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]4880location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4881the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4882intrinsic may only be used in a function which <a href="#gc">specifies a GC
4883algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4884
4885</div>
4886
4887
4888<!-- _______________________________________________________________________ -->
4889<div class="doc_subsubsection">
4890 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4891</div>
4892
4893<div class="doc_text">
4894
4895<h5>Syntax:</h5>
4896
4897<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4898 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4899</pre>
4900
4901<h5>Overview:</h5>
4902
4903<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4904locations, allowing garbage collector implementations that require read
4905barriers.</p>
4906
4907<h5>Arguments:</h5>
4908
4909<p>The second argument is the address to read from, which should be an address
4910allocated from the garbage collector. The first object is a pointer to the
4911start of the referenced object, if needed by the language runtime (otherwise
4912null).</p>
4913
4914<h5>Semantics:</h5>
4915
4916<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4917instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4918garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4919may only be used in a function which <a href="#gc">specifies a GC
4920algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4921
4922</div>
4923
4924
4925<!-- _______________________________________________________________________ -->
4926<div class="doc_subsubsection">
4927 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4928</div>
4929
4930<div class="doc_text">
4931
4932<h5>Syntax:</h5>
4933
4934<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4935 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4936</pre>
4937
4938<h5>Overview:</h5>
4939
4940<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4941locations, allowing garbage collector implementations that require write
4942barriers (such as generational or reference counting collectors).</p>
4943
4944<h5>Arguments:</h5>
4945
4946<p>The first argument is the reference to store, the second is the start of the
4947object to store it to, and the third is the address of the field of Obj to
4948store to. If the runtime does not require a pointer to the object, Obj may be
4949null.</p>
4950
4951<h5>Semantics:</h5>
4952
4953<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4954instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4955garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4956may only be used in a function which <a href="#gc">specifies a GC
4957algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4958
4959</div>
4960
4961
4962
4963<!-- ======================================================================= -->
4964<div class="doc_subsection">
4965 <a name="int_codegen">Code Generator Intrinsics</a>
4966</div>
4967
4968<div class="doc_text">
4969<p>
4970These intrinsics are provided by LLVM to expose special features that may only
4971be implemented with code generator support.
4972</p>
4973
4974</div>
4975
4976<!-- _______________________________________________________________________ -->
4977<div class="doc_subsubsection">
4978 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4979</div>
4980
4981<div class="doc_text">
4982
4983<h5>Syntax:</h5>
4984<pre>
4985 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4986</pre>
4987
4988<h5>Overview:</h5>
4989
4990<p>
4991The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4992target-specific value indicating the return address of the current function
4993or one of its callers.
4994</p>
4995
4996<h5>Arguments:</h5>
4997
4998<p>
4999The argument to this intrinsic indicates which function to return the address
5000for. Zero indicates the calling function, one indicates its caller, etc. The
5001argument is <b>required</b> to be a constant integer value.
5002</p>
5003
5004<h5>Semantics:</h5>
5005
5006<p>
5007The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5008the return address of the specified call frame, or zero if it cannot be
5009identified. The value returned by this intrinsic is likely to be incorrect or 0
5010for arguments other than zero, so it should only be used for debugging purposes.
5011</p>
5012
5013<p>
5014Note that calling this intrinsic does not prevent function inlining or other
5015aggressive transformations, so the value returned may not be that of the obvious
5016source-language caller.
5017</p>
5018</div>
5019
5020
5021<!-- _______________________________________________________________________ -->
5022<div class="doc_subsubsection">
5023 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5024</div>
5025
5026<div class="doc_text">
5027
5028<h5>Syntax:</h5>
5029<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5030 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5031</pre>
5032
5033<h5>Overview:</h5>
5034
5035<p>
5036The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5037target-specific frame pointer value for the specified stack frame.
5038</p>
5039
5040<h5>Arguments:</h5>
5041
5042<p>
5043The argument to this intrinsic indicates which function to return the frame
5044pointer for. Zero indicates the calling function, one indicates its caller,
5045etc. The argument is <b>required</b> to be a constant integer value.
5046</p>
5047
5048<h5>Semantics:</h5>
5049
5050<p>
5051The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5052the frame address of the specified call frame, or zero if it cannot be
5053identified. The value returned by this intrinsic is likely to be incorrect or 0
5054for arguments other than zero, so it should only be used for debugging purposes.
5055</p>
5056
5057<p>
5058Note that calling this intrinsic does not prevent function inlining or other
5059aggressive transformations, so the value returned may not be that of the obvious
5060source-language caller.
5061</p>
5062</div>
5063
5064<!-- _______________________________________________________________________ -->
5065<div class="doc_subsubsection">
5066 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5067</div>
5068
5069<div class="doc_text">
5070
5071<h5>Syntax:</h5>
5072<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5073 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5074</pre>
5075
5076<h5>Overview:</h5>
5077
5078<p>
5079The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5080the function stack, for use with <a href="#int_stackrestore">
5081<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5082features like scoped automatic variable sized arrays in C99.
5083</p>
5084
5085<h5>Semantics:</h5>
5086
5087<p>
5088This intrinsic returns a opaque pointer value that can be passed to <a
5089href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5090<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5091<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5092state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5093practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5094that were allocated after the <tt>llvm.stacksave</tt> was executed.
5095</p>
5096
5097</div>
5098
5099<!-- _______________________________________________________________________ -->
5100<div class="doc_subsubsection">
5101 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5102</div>
5103
5104<div class="doc_text">
5105
5106<h5>Syntax:</h5>
5107<pre>
5108 declare void @llvm.stackrestore(i8 * %ptr)
5109</pre>
5110
5111<h5>Overview:</h5>
5112
5113<p>
5114The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5115the function stack to the state it was in when the corresponding <a
5116href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5117useful for implementing language features like scoped automatic variable sized
5118arrays in C99.
5119</p>
5120
5121<h5>Semantics:</h5>
5122
5123<p>
5124See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5125</p>
5126
5127</div>
5128
5129
5130<!-- _______________________________________________________________________ -->
5131<div class="doc_subsubsection">
5132 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5133</div>
5134
5135<div class="doc_text">
5136
5137<h5>Syntax:</h5>
5138<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5139 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]5140</pre>
5141
5142<h5>Overview:</h5>
5143
5144
5145<p>
5146The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5147a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5148no
5149effect on the behavior of the program but can change its performance
5150characteristics.
5151</p>
5152
5153<h5>Arguments:</h5>
5154
5155<p>
5156<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5157determining if the fetch should be for a read (0) or write (1), and
5158<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5159locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5160<tt>locality</tt> arguments must be constant integers.
5161</p>
5162
5163<h5>Semantics:</h5>
5164
5165<p>
5166This intrinsic does not modify the behavior of the program. In particular,
5167prefetches cannot trap and do not produce a value. On targets that support this
5168intrinsic, the prefetch can provide hints to the processor cache for better
5169performance.
5170</p>
5171
5172</div>
5173
5174<!-- _______________________________________________________________________ -->
5175<div class="doc_subsubsection">
5176 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5177</div>
5178
5179<div class="doc_text">
5180
5181<h5>Syntax:</h5>
5182<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5183 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5184</pre>
5185
5186<h5>Overview:</h5>
5187
5188
5189<p>
5190The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5191(PC) in a region of
5192code to simulators and other tools. The method is target specific, but it is
5193expected that the marker will use exported symbols to transmit the PC of the
5194marker.
5195The marker makes no guarantees that it will remain with any specific instruction
5196after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5197optimizations. The intended use is to be inserted after optimizations to allow
5198correlations of simulation runs.
5199</p>
5200
5201<h5>Arguments:</h5>
5202
5203<p>
5204<tt>id</tt> is a numerical id identifying the marker.
5205</p>
5206
5207<h5>Semantics:</h5>
5208
5209<p>
5210This intrinsic does not modify the behavior of the program. Backends that do not
5211support this intrinisic may ignore it.
5212</p>
5213
5214</div>
5215
5216<!-- _______________________________________________________________________ -->
5217<div class="doc_subsubsection">
5218 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5219</div>
5220
5221<div class="doc_text">
5222
5223<h5>Syntax:</h5>
5224<pre>
5225 declare i64 @llvm.readcyclecounter( )
5226</pre>
5227
5228<h5>Overview:</h5>
5229
5230
5231<p>
5232The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5233counter register (or similar low latency, high accuracy clocks) on those targets
5234that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5235As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5236should only be used for small timings.
5237</p>
5238
5239<h5>Semantics:</h5>
5240
5241<p>
5242When directly supported, reading the cycle counter should not modify any memory.
5243Implementations are allowed to either return a application specific value or a
5244system wide value. On backends without support, this is lowered to a constant 0.
5245</p>
5246
5247</div>
5248
5249<!-- ======================================================================= -->
5250<div class="doc_subsection">
5251 <a name="int_libc">Standard C Library Intrinsics</a>
5252</div>
5253
5254<div class="doc_text">
5255<p>
5256LLVM provides intrinsics for a few important standard C library functions.
5257These intrinsics allow source-language front-ends to pass information about the
5258alignment of the pointer arguments to the code generator, providing opportunity
5259for more efficient code generation.
5260</p>
5261
5262</div>
5263
5264<!-- _______________________________________________________________________ -->
5265<div class="doc_subsubsection">
5266 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5267</div>
5268
5269<div class="doc_text">
5270
5271<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5272<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5273width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5275 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5276 i8 &lt;len&gt;, i32 &lt;align&gt;)
5277 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5278 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5279 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5280 i32 &lt;len&gt;, i32 &lt;align&gt;)
5281 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5282 i64 &lt;len&gt;, i32 &lt;align&gt;)
5283</pre>
5284
5285<h5>Overview:</h5>
5286
5287<p>
5288The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5289location to the destination location.
5290</p>
5291
5292<p>
5293Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5294intrinsics do not return a value, and takes an extra alignment argument.
5295</p>
5296
5297<h5>Arguments:</h5>
5298
5299<p>
5300The first argument is a pointer to the destination, the second is a pointer to
5301the source. The third argument is an integer argument
5302specifying the number of bytes to copy, and the fourth argument is the alignment
5303of the source and destination locations.
5304</p>
5305
5306<p>
5307If the call to this intrinisic has an alignment value that is not 0 or 1, then
5308the caller guarantees that both the source and destination pointers are aligned
5309to that boundary.
5310</p>
5311
5312<h5>Semantics:</h5>
5313
5314<p>
5315The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5316location to the destination location, which are not allowed to overlap. It
5317copies "len" bytes of memory over. If the argument is known to be aligned to
5318some boundary, this can be specified as the fourth argument, otherwise it should
5319be set to 0 or 1.
5320</p>
5321</div>
5322
5323
5324<!-- _______________________________________________________________________ -->
5325<div class="doc_subsubsection">
5326 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5327</div>
5328
5329<div class="doc_text">
5330
5331<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5332<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5333width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5334<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5335 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5336 i8 &lt;len&gt;, i32 &lt;align&gt;)
5337 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5338 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5339 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5340 i32 &lt;len&gt;, i32 &lt;align&gt;)
5341 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5342 i64 &lt;len&gt;, i32 &lt;align&gt;)
5343</pre>
5344
5345<h5>Overview:</h5>
5346
5347<p>
5348The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5349location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5350'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5351</p>
5352
5353<p>
5354Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5355intrinsics do not return a value, and takes an extra alignment argument.
5356</p>
5357
5358<h5>Arguments:</h5>
5359
5360<p>
5361The first argument is a pointer to the destination, the second is a pointer to
5362the source. The third argument is an integer argument
5363specifying the number of bytes to copy, and the fourth argument is the alignment
5364of the source and destination locations.
5365</p>
5366
5367<p>
5368If the call to this intrinisic has an alignment value that is not 0 or 1, then
5369the caller guarantees that the source and destination pointers are aligned to
5370that boundary.
5371</p>
5372
5373<h5>Semantics:</h5>
5374
5375<p>
5376The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5377location to the destination location, which may overlap. It
5378copies "len" bytes of memory over. If the argument is known to be aligned to
5379some boundary, this can be specified as the fourth argument, otherwise it should
5380be set to 0 or 1.
5381</p>
5382</div>
5383
5384
5385<!-- _______________________________________________________________________ -->
5386<div class="doc_subsubsection">
5387 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5388</div>
5389
5390<div class="doc_text">
5391
5392<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5393<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5394width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5395<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5396 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5397 i8 &lt;len&gt;, i32 &lt;align&gt;)
5398 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5399 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5400 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5401 i32 &lt;len&gt;, i32 &lt;align&gt;)
5402 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5403 i64 &lt;len&gt;, i32 &lt;align&gt;)
5404</pre>
5405
5406<h5>Overview:</h5>
5407
5408<p>
5409The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5410byte value.
5411</p>
5412
5413<p>
5414Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5415does not return a value, and takes an extra alignment argument.
5416</p>
5417
5418<h5>Arguments:</h5>
5419
5420<p>
5421The first argument is a pointer to the destination to fill, the second is the
5422byte value to fill it with, the third argument is an integer
5423argument specifying the number of bytes to fill, and the fourth argument is the
5424known alignment of destination location.
5425</p>
5426
5427<p>
5428If the call to this intrinisic has an alignment value that is not 0 or 1, then
5429the caller guarantees that the destination pointer is aligned to that boundary.
5430</p>
5431
5432<h5>Semantics:</h5>
5433
5434<p>
5435The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5436the
5437destination location. If the argument is known to be aligned to some boundary,
5438this can be specified as the fourth argument, otherwise it should be set to 0 or
54391.
5440</p>
5441</div>
5442
5443
5444<!-- _______________________________________________________________________ -->
5445<div class="doc_subsubsection">
5446 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5447</div>
5448
5449<div class="doc_text">
5450
5451<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5452<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]5453floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5454types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5455<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5456 declare float @llvm.sqrt.f32(float %Val)
5457 declare double @llvm.sqrt.f64(double %Val)
5458 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5459 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5460 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5461</pre>
5462
5463<h5>Overview:</h5>
5464
5465<p>
5466The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5467returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5468<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5469negative numbers other than -0.0 (which allows for better optimization, because
5470there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5471defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5472</p>
5473
5474<h5>Arguments:</h5>
5475
5476<p>
5477The argument and return value are floating point numbers of the same type.
5478</p>
5479
5480<h5>Semantics:</h5>
5481
5482<p>
5483This function returns the sqrt of the specified operand if it is a nonnegative
5484floating point number.
5485</p>
5486</div>
5487
5488<!-- _______________________________________________________________________ -->
5489<div class="doc_subsubsection">
5490 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5491</div>
5492
5493<div class="doc_text">
5494
5495<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5496<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]5497floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5498types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5499<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5500 declare float @llvm.powi.f32(float %Val, i32 %power)
5501 declare double @llvm.powi.f64(double %Val, i32 %power)
5502 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5503 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5504 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5505</pre>
5506
5507<h5>Overview:</h5>
5508
5509<p>
5510The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5511specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5512multiplications is not defined. When a vector of floating point type is
5513used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514</p>
5515
5516<h5>Arguments:</h5>
5517
5518<p>
5519The second argument is an integer power, and the first is a value to raise to
5520that power.
5521</p>
5522
5523<h5>Semantics:</h5>
5524
5525<p>
5526This function returns the first value raised to the second power with an
5527unspecified sequence of rounding operations.</p>
5528</div>
5529
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5530<!-- _______________________________________________________________________ -->
5531<div class="doc_subsubsection">
5532 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5533</div>
5534
5535<div class="doc_text">
5536
5537<h5>Syntax:</h5>
5538<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5539floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5540types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5541<pre>
5542 declare float @llvm.sin.f32(float %Val)
5543 declare double @llvm.sin.f64(double %Val)
5544 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5545 declare fp128 @llvm.sin.f128(fp128 %Val)
5546 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5547</pre>
5548
5549<h5>Overview:</h5>
5550
5551<p>
5552The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5553</p>
5554
5555<h5>Arguments:</h5>
5556
5557<p>
5558The argument and return value are floating point numbers of the same type.
5559</p>
5560
5561<h5>Semantics:</h5>
5562
5563<p>
5564This function returns the sine of the specified operand, returning the
5565same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5566conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5567</div>
5568
5569<!-- _______________________________________________________________________ -->
5570<div class="doc_subsubsection">
5571 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5572</div>
5573
5574<div class="doc_text">
5575
5576<h5>Syntax:</h5>
5577<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5578floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5579types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5580<pre>
5581 declare float @llvm.cos.f32(float %Val)
5582 declare double @llvm.cos.f64(double %Val)
5583 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5584 declare fp128 @llvm.cos.f128(fp128 %Val)
5585 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5586</pre>
5587
5588<h5>Overview:</h5>
5589
5590<p>
5591The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5592</p>
5593
5594<h5>Arguments:</h5>
5595
5596<p>
5597The argument and return value are floating point numbers of the same type.
5598</p>
5599
5600<h5>Semantics:</h5>
5601
5602<p>
5603This function returns the cosine of the specified operand, returning the
5604same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5605conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5606</div>
5607
5608<!-- _______________________________________________________________________ -->
5609<div class="doc_subsubsection">
5610 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5611</div>
5612
5613<div class="doc_text">
5614
5615<h5>Syntax:</h5>
5616<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5617floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5618types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5619<pre>
5620 declare float @llvm.pow.f32(float %Val, float %Power)
5621 declare double @llvm.pow.f64(double %Val, double %Power)
5622 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5623 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5624 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5625</pre>
5626
5627<h5>Overview:</h5>
5628
5629<p>
5630The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5631specified (positive or negative) power.
5632</p>
5633
5634<h5>Arguments:</h5>
5635
5636<p>
5637The second argument is a floating point power, and the first is a value to
5638raise to that power.
5639</p>
5640
5641<h5>Semantics:</h5>
5642
5643<p>
5644This function returns the first value raised to the second power,
5645returning the
5646same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5647conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5648</div>
5649
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5650
5651<!-- ======================================================================= -->
5652<div class="doc_subsection">
5653 <a name="int_manip">Bit Manipulation Intrinsics</a>
5654</div>
5655
5656<div class="doc_text">
5657<p>
5658LLVM provides intrinsics for a few important bit manipulation operations.
5659These allow efficient code generation for some algorithms.
5660</p>
5661
5662</div>
5663
5664<!-- _______________________________________________________________________ -->
5665<div class="doc_subsubsection">
5666 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5667</div>
5668
5669<div class="doc_text">
5670
5671<h5>Syntax:</h5>
5672<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5673type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5674<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5675 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5676 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5677 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5678</pre>
5679
5680<h5>Overview:</h5>
5681
5682<p>
5683The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5684values with an even number of bytes (positive multiple of 16 bits). These are
5685useful for performing operations on data that is not in the target's native
5686byte order.
5687</p>
5688
5689<h5>Semantics:</h5>
5690
5691<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5692The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5694intrinsic returns an i32 value that has the four bytes of the input i32
5695swapped, 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]5696i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5697<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5698additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5699</p>
5700
5701</div>
5702
5703<!-- _______________________________________________________________________ -->
5704<div class="doc_subsubsection">
5705 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5706</div>
5707
5708<div class="doc_text">
5709
5710<h5>Syntax:</h5>
5711<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]5712width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5713<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5714 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5715 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5716 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5717 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5718 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5719</pre>
5720
5721<h5>Overview:</h5>
5722
5723<p>
5724The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5725value.
5726</p>
5727
5728<h5>Arguments:</h5>
5729
5730<p>
5731The only argument is the value to be counted. The argument may be of any
5732integer type. The return type must match the argument type.
5733</p>
5734
5735<h5>Semantics:</h5>
5736
5737<p>
5738The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5739</p>
5740</div>
5741
5742<!-- _______________________________________________________________________ -->
5743<div class="doc_subsubsection">
5744 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5745</div>
5746
5747<div class="doc_text">
5748
5749<h5>Syntax:</h5>
5750<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]5751integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5752<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5753 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5754 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5755 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5756 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5757 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5758</pre>
5759
5760<h5>Overview:</h5>
5761
5762<p>
5763The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5764leading zeros in a variable.
5765</p>
5766
5767<h5>Arguments:</h5>
5768
5769<p>
5770The only argument is the value to be counted. The argument may be of any
5771integer type. The return type must match the argument type.
5772</p>
5773
5774<h5>Semantics:</h5>
5775
5776<p>
5777The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5778in a variable. If the src == 0 then the result is the size in bits of the type
5779of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5780</p>
5781</div>
5782
5783
5784
5785<!-- _______________________________________________________________________ -->
5786<div class="doc_subsubsection">
5787 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5788</div>
5789
5790<div class="doc_text">
5791
5792<h5>Syntax:</h5>
5793<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]5794integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5795<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5796 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5797 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5798 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5799 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5800 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5801</pre>
5802
5803<h5>Overview:</h5>
5804
5805<p>
5806The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5807trailing zeros.
5808</p>
5809
5810<h5>Arguments:</h5>
5811
5812<p>
5813The only argument is the value to be counted. The argument may be of any
5814integer type. The return type must match the argument type.
5815</p>
5816
5817<h5>Semantics:</h5>
5818
5819<p>
5820The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5821in a variable. If the src == 0 then the result is the size in bits of the type
5822of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5823</p>
5824</div>
5825
5826<!-- _______________________________________________________________________ -->
5827<div class="doc_subsubsection">
5828 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5829</div>
5830
5831<div class="doc_text">
5832
5833<h5>Syntax:</h5>
5834<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5835on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5836<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5837 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5838 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5839</pre>
5840
5841<h5>Overview:</h5>
5842<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5843range of bits from an integer value and returns them in the same bit width as
5844the original value.</p>
5845
5846<h5>Arguments:</h5>
5847<p>The first argument, <tt>%val</tt> and the result may be integer types of
5848any bit width but they must have the same bit width. The second and third
5849arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5850
5851<h5>Semantics:</h5>
5852<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5853of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5854<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5855operates in forward mode.</p>
5856<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5857right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5858only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5859<ol>
5860 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5861 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5862 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5863 to determine the number of bits to retain.</li>
5864 <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]5865 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5866</ol>
5867<p>In reverse mode, a similar computation is made except that the bits are
5868returned in the reverse order. So, for example, if <tt>X</tt> has the value
5869<tt>i16 0x0ACF (101011001111)</tt> and we apply
5870<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5871<tt>i16 0x0026 (000000100110)</tt>.</p>
5872</div>
5873
5874<div class="doc_subsubsection">
5875 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5876</div>
5877
5878<div class="doc_text">
5879
5880<h5>Syntax:</h5>
5881<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5882on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5883<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5884 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5885 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]5886</pre>
5887
5888<h5>Overview:</h5>
5889<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5890of bits in an integer value with another integer value. It returns the integer
5891with the replaced bits.</p>
5892
5893<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5894<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5895any 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]5896whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5897integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5898type since they specify only a bit index.</p>
5899
5900<h5>Semantics:</h5>
5901<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5902of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5903<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5904operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5906<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5907truncating it down to the size of the replacement area or zero extending it
5908up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5909
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5910<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5911are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5912in <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]5913to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5914
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5915<p>In reverse mode, a similar computation is made except that the bits are
5916reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5917<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]5918
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5919<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5920
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5921<pre>
5922 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5923 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5924 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5925 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5926 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5927</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5928
5929</div>
5930
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5931<!-- ======================================================================= -->
5932<div class="doc_subsection">
5933 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
5934</div>
5935
5936<div class="doc_text">
5937<p>
5938LLVM provides intrinsics for some arithmetic with overflow operations.
5939</p>
5940
5941</div>
5942
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5943<!-- _______________________________________________________________________ -->
5944<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5945 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5946</div>
5947
5948<div class="doc_text">
5949
5950<h5>Syntax:</h5>
5951
5952<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]5953on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5954
5955<pre>
5956 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
5957 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5958 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
5959</pre>
5960
5961<h5>Overview:</h5>
5962
5963<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5964a signed addition of the two arguments, and indicate whether an overflow
5965occurred during the signed summation.</p>
5966
5967<h5>Arguments:</h5>
5968
5969<p>The arguments (%a and %b) and the first element of the result structure may
5970be of integer types of any bit width, but they must have the same bit width. The
5971second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
5972and <tt>%b</tt> are the two values that will undergo signed addition.</p>
5973
5974<h5>Semantics:</h5>
5975
5976<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
5977a signed addition of the two variables. They return a structure &mdash; the
5978first element of which is the signed summation, and the second element of which
5979is a bit specifying if the signed summation resulted in an overflow.</p>
5980
5981<h5>Examples:</h5>
5982<pre>
5983 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
5984 %sum = extractvalue {i32, i1} %res, 0
5985 %obit = extractvalue {i32, i1} %res, 1
5986 br i1 %obit, label %overflow, label %normal
5987</pre>
5988
5989</div>
5990
5991<!-- _______________________________________________________________________ -->
5992<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]5993 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5994</div>
5995
5996<div class="doc_text">
5997
5998<h5>Syntax:</h5>
5999
6000<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]6001on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6002
6003<pre>
6004 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6005 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6006 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6007</pre>
6008
6009<h5>Overview:</h5>
6010
6011<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6012an unsigned addition of the two arguments, and indicate whether a carry occurred
6013during the unsigned summation.</p>
6014
6015<h5>Arguments:</h5>
6016
6017<p>The arguments (%a and %b) and the first element of the result structure may
6018be of integer types of any bit width, but they must have the same bit width. The
6019second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6020and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6021
6022<h5>Semantics:</h5>
6023
6024<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6025an unsigned addition of the two arguments. They return a structure &mdash; the
6026first element of which is the sum, and the second element of which is a bit
6027specifying if the unsigned summation resulted in a carry.</p>
6028
6029<h5>Examples:</h5>
6030<pre>
6031 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6032 %sum = extractvalue {i32, i1} %res, 0
6033 %obit = extractvalue {i32, i1} %res, 1
6034 br i1 %obit, label %carry, label %normal
6035</pre>
6036
6037</div>
6038
6039<!-- _______________________________________________________________________ -->
6040<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6041 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6042</div>
6043
6044<div class="doc_text">
6045
6046<h5>Syntax:</h5>
6047
6048<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]6049on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6050
6051<pre>
6052 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6053 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6054 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6055</pre>
6056
6057<h5>Overview:</h5>
6058
6059<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6060a signed subtraction of the two arguments, and indicate whether an overflow
6061occurred during the signed subtraction.</p>
6062
6063<h5>Arguments:</h5>
6064
6065<p>The arguments (%a and %b) and the first element of the result structure may
6066be of integer types of any bit width, but they must have the same bit width. The
6067second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6068and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6069
6070<h5>Semantics:</h5>
6071
6072<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6073a signed subtraction of the two arguments. They return a structure &mdash; the
6074first element of which is the subtraction, and the second element of which is a bit
6075specifying if the signed subtraction resulted in an overflow.</p>
6076
6077<h5>Examples:</h5>
6078<pre>
6079 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6080 %sum = extractvalue {i32, i1} %res, 0
6081 %obit = extractvalue {i32, i1} %res, 1
6082 br i1 %obit, label %overflow, label %normal
6083</pre>
6084
6085</div>
6086
6087<!-- _______________________________________________________________________ -->
6088<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6089 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6090</div>
6091
6092<div class="doc_text">
6093
6094<h5>Syntax:</h5>
6095
6096<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]6097on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6098
6099<pre>
6100 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6101 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6102 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6103</pre>
6104
6105<h5>Overview:</h5>
6106
6107<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6108an unsigned subtraction of the two arguments, and indicate whether an overflow
6109occurred during the unsigned subtraction.</p>
6110
6111<h5>Arguments:</h5>
6112
6113<p>The arguments (%a and %b) and the first element of the result structure may
6114be of integer types of any bit width, but they must have the same bit width. The
6115second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6116and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6117
6118<h5>Semantics:</h5>
6119
6120<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6121an unsigned subtraction of the two arguments. They return a structure &mdash; the
6122first element of which is the subtraction, and the second element of which is a bit
6123specifying if the unsigned subtraction resulted in an overflow.</p>
6124
6125<h5>Examples:</h5>
6126<pre>
6127 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6128 %sum = extractvalue {i32, i1} %res, 0
6129 %obit = extractvalue {i32, i1} %res, 1
6130 br i1 %obit, label %overflow, label %normal
6131</pre>
6132
6133</div>
6134
6135<!-- _______________________________________________________________________ -->
6136<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6137 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6138</div>
6139
6140<div class="doc_text">
6141
6142<h5>Syntax:</h5>
6143
6144<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]6145on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6146
6147<pre>
6148 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6149 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6150 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6151</pre>
6152
6153<h5>Overview:</h5>
6154
6155<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6156a signed multiplication of the two arguments, and indicate whether an overflow
6157occurred during the signed multiplication.</p>
6158
6159<h5>Arguments:</h5>
6160
6161<p>The arguments (%a and %b) and the first element of the result structure may
6162be of integer types of any bit width, but they must have the same bit width. The
6163second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6164and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6165
6166<h5>Semantics:</h5>
6167
6168<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6169a signed multiplication of the two arguments. They return a structure &mdash;
6170the first element of which is the multiplication, and the second element of
6171which is a bit specifying if the signed multiplication resulted in an
6172overflow.</p>
6173
6174<h5>Examples:</h5>
6175<pre>
6176 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6177 %sum = extractvalue {i32, i1} %res, 0
6178 %obit = extractvalue {i32, i1} %res, 1
6179 br i1 %obit, label %overflow, label %normal
6180</pre>
6181
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6182</div>
6183
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6184<!-- _______________________________________________________________________ -->
6185<div class="doc_subsubsection">
6186 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6187</div>
6188
6189<div class="doc_text">
6190
6191<h5>Syntax:</h5>
6192
6193<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6194on any integer bit width.</p>
6195
6196<pre>
6197 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6198 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6199 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6200</pre>
6201
6202<h5>Overview:</h5>
6203
6204<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6205actively being fixed, but it should not currently be used!</i></p>
6206
6207<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6208a unsigned multiplication of the two arguments, and indicate whether an overflow
6209occurred during the unsigned multiplication.</p>
6210
6211<h5>Arguments:</h5>
6212
6213<p>The arguments (%a and %b) and the first element of the result structure may
6214be of integer types of any bit width, but they must have the same bit width. The
6215second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6216and <tt>%b</tt> are the two values that will undergo unsigned
6217multiplication.</p>
6218
6219<h5>Semantics:</h5>
6220
6221<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6222an unsigned multiplication of the two arguments. They return a structure &mdash;
6223the first element of which is the multiplication, and the second element of
6224which is a bit specifying if the unsigned multiplication resulted in an
6225overflow.</p>
6226
6227<h5>Examples:</h5>
6228<pre>
6229 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6230 %sum = extractvalue {i32, i1} %res, 0
6231 %obit = extractvalue {i32, i1} %res, 1
6232 br i1 %obit, label %overflow, label %normal
6233</pre>
6234
6235</div>
6236
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6237<!-- ======================================================================= -->
6238<div class="doc_subsection">
6239 <a name="int_debugger">Debugger Intrinsics</a>
6240</div>
6241
6242<div class="doc_text">
6243<p>
6244The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6245are described in the <a
6246href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6247Debugging</a> document.
6248</p>
6249</div>
6250
6251
6252<!-- ======================================================================= -->
6253<div class="doc_subsection">
6254 <a name="int_eh">Exception Handling Intrinsics</a>
6255</div>
6256
6257<div class="doc_text">
6258<p> The LLVM exception handling intrinsics (which all start with
6259<tt>llvm.eh.</tt> prefix), are described in the <a
6260href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6261Handling</a> document. </p>
6262</div>
6263
6264<!-- ======================================================================= -->
6265<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6266 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6267</div>
6268
6269<div class="doc_text">
6270<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6271 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6272 the <tt>nest</tt> attribute, from a function. The result is a callable
6273 function pointer lacking the nest parameter - the caller does not need
6274 to provide a value for it. Instead, the value to use is stored in
6275 advance in a "trampoline", a block of memory usually allocated
6276 on the stack, which also contains code to splice the nest value into the
6277 argument list. This is used to implement the GCC nested function address
6278 extension.
6279</p>
6280<p>
6281 For example, if the function is
6282 <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]6283 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]6284<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6285 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6286 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6287 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6288 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6289</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6290 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6291 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6292</div>
6293
6294<!-- _______________________________________________________________________ -->
6295<div class="doc_subsubsection">
6296 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6297</div>
6298<div class="doc_text">
6299<h5>Syntax:</h5>
6300<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6301declare 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]6302</pre>
6303<h5>Overview:</h5>
6304<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6305 This fills the memory pointed to by <tt>tramp</tt> with code
6306 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6307</p>
6308<h5>Arguments:</h5>
6309<p>
6310 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6311 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6312 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6313 intrinsic. Note that the size and the alignment are target-specific - LLVM
6314 currently provides no portable way of determining them, so a front-end that
6315 generates this intrinsic needs to have some target-specific knowledge.
6316 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]6317</p>
6318<h5>Semantics:</h5>
6319<p>
6320 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6321 dependent code, turning it into a function. A pointer to this function is
6322 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6323 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6324 before being called. The new function's signature is the same as that of
6325 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6326 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6327 of pointer type. Calling the new function is equivalent to calling
6328 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6329 missing <tt>nest</tt> argument. If, after calling
6330 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6331 modified, then the effect of any later call to the returned function pointer is
6332 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6333</p>
6334</div>
6335
6336<!-- ======================================================================= -->
6337<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6338 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6339</div>
6340
6341<div class="doc_text">
6342<p>
6343 These intrinsic functions expand the "universal IR" of LLVM to represent
6344 hardware constructs for atomic operations and memory synchronization. This
6345 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6346 is aimed at a low enough level to allow any programming models or APIs
6347 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6348 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6349 hardware behavior. Just as hardware provides a "universal IR" for source
6350 languages, it also provides a starting point for developing a "universal"
6351 atomic operation and synchronization IR.
6352</p>
6353<p>
6354 These do <em>not</em> form an API such as high-level threading libraries,
6355 software transaction memory systems, atomic primitives, and intrinsic
6356 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6357 application libraries. The hardware interface provided by LLVM should allow
6358 a clean implementation of all of these APIs and parallel programming models.
6359 No one model or paradigm should be selected above others unless the hardware
6360 itself ubiquitously does so.
6361
6362</p>
6363</div>
6364
6365<!-- _______________________________________________________________________ -->
6366<div class="doc_subsubsection">
6367 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6368</div>
6369<div class="doc_text">
6370<h5>Syntax:</h5>
6371<pre>
6372declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6373i1 &lt;device&gt; )
6374
6375</pre>
6376<h5>Overview:</h5>
6377<p>
6378 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6379 specific pairs of memory access types.
6380</p>
6381<h5>Arguments:</h5>
6382<p>
6383 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6384 The first four arguments enables a specific barrier as listed below. The fith
6385 argument specifies that the barrier applies to io or device or uncached memory.
6386
6387</p>
6388 <ul>
6389 <li><tt>ll</tt>: load-load barrier</li>
6390 <li><tt>ls</tt>: load-store barrier</li>
6391 <li><tt>sl</tt>: store-load barrier</li>
6392 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6393 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6394 </ul>
6395<h5>Semantics:</h5>
6396<p>
6397 This intrinsic causes the system to enforce some ordering constraints upon
6398 the loads and stores of the program. This barrier does not indicate
6399 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6400 which they occur. For any of the specified pairs of load and store operations
6401 (f.ex. load-load, or store-load), all of the first operations preceding the
6402 barrier will complete before any of the second operations succeeding the
6403 barrier begin. Specifically the semantics for each pairing is as follows:
6404</p>
6405 <ul>
6406 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6407 after the barrier begins.</li>
6408
6409 <li><tt>ls</tt>: All loads before the barrier must complete before any
6410 store after the barrier begins.</li>
6411 <li><tt>ss</tt>: All stores before the barrier must complete before any
6412 store after the barrier begins.</li>
6413 <li><tt>sl</tt>: All stores before the barrier must complete before any
6414 load after the barrier begins.</li>
6415 </ul>
6416<p>
6417 These semantics are applied with a logical "and" behavior when more than one
6418 is enabled in a single memory barrier intrinsic.
6419</p>
6420<p>
6421 Backends may implement stronger barriers than those requested when they do not
6422 support as fine grained a barrier as requested. Some architectures do not
6423 need all types of barriers and on such architectures, these become noops.
6424</p>
6425<h5>Example:</h5>
6426<pre>
6427%ptr = malloc i32
6428 store i32 4, %ptr
6429
6430%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6431 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6432 <i>; guarantee the above finishes</i>
6433 store i32 8, %ptr <i>; before this begins</i>
6434</pre>
6435</div>
6436
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6437<!-- _______________________________________________________________________ -->
6438<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6439 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6440</div>
6441<div class="doc_text">
6442<h5>Syntax:</h5>
6443<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6444 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6445 any integer bit width and for different address spaces. Not all targets
6446 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6447
6448<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6449declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6450declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6451declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6452declare 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]6453
6454</pre>
6455<h5>Overview:</h5>
6456<p>
6457 This loads a value in memory and compares it to a given value. If they are
6458 equal, it stores a new value into the memory.
6459</p>
6460<h5>Arguments:</h5>
6461<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6462 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6463 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6464 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6465 this integer type. While any bit width integer may be used, targets may only
6466 lower representations they support in hardware.
6467
6468</p>
6469<h5>Semantics:</h5>
6470<p>
6471 This entire intrinsic must be executed atomically. It first loads the value
6472 in memory pointed to by <tt>ptr</tt> and compares it with the value
6473 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6474 loaded value is yielded in all cases. This provides the equivalent of an
6475 atomic compare-and-swap operation within the SSA framework.
6476</p>
6477<h5>Examples:</h5>
6478
6479<pre>
6480%ptr = malloc i32
6481 store i32 4, %ptr
6482
6483%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6484%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6485 <i>; yields {i32}:result1 = 4</i>
6486%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6487%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6488
6489%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6490%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6491 <i>; yields {i32}:result2 = 8</i>
6492%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6493
6494%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6495</pre>
6496</div>
6497
6498<!-- _______________________________________________________________________ -->
6499<div class="doc_subsubsection">
6500 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6501</div>
6502<div class="doc_text">
6503<h5>Syntax:</h5>
6504
6505<p>
6506 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6507 integer bit width. Not all targets support all bit widths however.</p>
6508<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6509declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6510declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6511declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6512declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6513
6514</pre>
6515<h5>Overview:</h5>
6516<p>
6517 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6518 the value from memory. It then stores the value in <tt>val</tt> in the memory
6519 at <tt>ptr</tt>.
6520</p>
6521<h5>Arguments:</h5>
6522
6523<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6524 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6525 <tt>val</tt> argument and the result must be integers of the same bit width.
6526 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6527 integer type. The targets may only lower integer representations they
6528 support.
6529</p>
6530<h5>Semantics:</h5>
6531<p>
6532 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6533 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6534 equivalent of an atomic swap operation within the SSA framework.
6535
6536</p>
6537<h5>Examples:</h5>
6538<pre>
6539%ptr = malloc i32
6540 store i32 4, %ptr
6541
6542%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6543%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6544 <i>; yields {i32}:result1 = 4</i>
6545%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6546%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6547
6548%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6549%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6550 <i>; yields {i32}:result2 = 8</i>
6551
6552%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6553%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6554</pre>
6555</div>
6556
6557<!-- _______________________________________________________________________ -->
6558<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6559 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6560
6561</div>
6562<div class="doc_text">
6563<h5>Syntax:</h5>
6564<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6565 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]6566 integer bit width. Not all targets support all bit widths however.</p>
6567<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6568declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6569declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6570declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6571declare 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]6572
6573</pre>
6574<h5>Overview:</h5>
6575<p>
6576 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6577 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6578</p>
6579<h5>Arguments:</h5>
6580<p>
6581
6582 The intrinsic takes two arguments, the first a pointer to an integer value
6583 and the second an integer value. The result is also an integer value. These
6584 integer types can have any bit width, but they must all have the same bit
6585 width. The targets may only lower integer representations they support.
6586</p>
6587<h5>Semantics:</h5>
6588<p>
6589 This intrinsic does a series of operations atomically. It first loads the
6590 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6591 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6592</p>
6593
6594<h5>Examples:</h5>
6595<pre>
6596%ptr = malloc i32
6597 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6598%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6599 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6600%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6601 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6602%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6603 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6604%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6605</pre>
6606</div>
6607
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6608<!-- _______________________________________________________________________ -->
6609<div class="doc_subsubsection">
6610 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6611
6612</div>
6613<div class="doc_text">
6614<h5>Syntax:</h5>
6615<p>
6616 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]6617 any integer bit width and for different address spaces. Not all targets
6618 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6619<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6620declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6621declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6622declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6623declare 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]6624
6625</pre>
6626<h5>Overview:</h5>
6627<p>
6628 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6629 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6630</p>
6631<h5>Arguments:</h5>
6632<p>
6633
6634 The intrinsic takes two arguments, the first a pointer to an integer value
6635 and the second an integer value. The result is also an integer value. These
6636 integer types can have any bit width, but they must all have the same bit
6637 width. The targets may only lower integer representations they support.
6638</p>
6639<h5>Semantics:</h5>
6640<p>
6641 This intrinsic does a series of operations atomically. It first loads the
6642 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6643 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6644</p>
6645
6646<h5>Examples:</h5>
6647<pre>
6648%ptr = malloc i32
6649 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6650%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6651 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6652%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6653 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6654%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6655 <i>; yields {i32}:result3 = 2</i>
6656%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6657</pre>
6658</div>
6659
6660<!-- _______________________________________________________________________ -->
6661<div class="doc_subsubsection">
6662 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6663 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6664 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6665 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6666
6667</div>
6668<div class="doc_text">
6669<h5>Syntax:</h5>
6670<p>
6671 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6672 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6673 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6674 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6675<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6676declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6677declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6678declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6679declare 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]6680
6681</pre>
6682
6683<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6684declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6685declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6686declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6687declare 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]6688
6689</pre>
6690
6691<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6692declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6693declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6694declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6695declare 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]6696
6697</pre>
6698
6699<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6700declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6701declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6702declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6703declare 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]6704
6705</pre>
6706<h5>Overview:</h5>
6707<p>
6708 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6709 the value stored in memory at <tt>ptr</tt>. It yields the original value
6710 at <tt>ptr</tt>.
6711</p>
6712<h5>Arguments:</h5>
6713<p>
6714
6715 These intrinsics take two arguments, the first a pointer to an integer value
6716 and the second an integer value. The result is also an integer value. These
6717 integer types can have any bit width, but they must all have the same bit
6718 width. The targets may only lower integer representations they support.
6719</p>
6720<h5>Semantics:</h5>
6721<p>
6722 These intrinsics does a series of operations atomically. They first load the
6723 value stored at <tt>ptr</tt>. They then do the bitwise operation
6724 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6725 value stored at <tt>ptr</tt>.
6726</p>
6727
6728<h5>Examples:</h5>
6729<pre>
6730%ptr = malloc i32
6731 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6732%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6733 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6734%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6735 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6736%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6737 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6738%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6739 <i>; yields {i32}:result3 = FF</i>
6740%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6741</pre>
6742</div>
6743
6744
6745<!-- _______________________________________________________________________ -->
6746<div class="doc_subsubsection">
6747 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6748 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6749 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6750 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6751
6752</div>
6753<div class="doc_text">
6754<h5>Syntax:</h5>
6755<p>
6756 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6757 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6758 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6759 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6760 support all bit widths however.</p>
6761<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6762declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6763declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6764declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6765declare 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]6766
6767</pre>
6768
6769<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6770declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6771declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6772declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6773declare 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]6774
6775</pre>
6776
6777<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6778declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6779declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6780declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6781declare 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]6782
6783</pre>
6784
6785<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6786declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6787declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6788declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6789declare 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]6790
6791</pre>
6792<h5>Overview:</h5>
6793<p>
6794 These intrinsics takes the signed or unsigned minimum or maximum of
6795 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6796 original value at <tt>ptr</tt>.
6797</p>
6798<h5>Arguments:</h5>
6799<p>
6800
6801 These intrinsics take two arguments, the first a pointer to an integer value
6802 and the second an integer value. The result is also an integer value. These
6803 integer types can have any bit width, but they must all have the same bit
6804 width. The targets may only lower integer representations they support.
6805</p>
6806<h5>Semantics:</h5>
6807<p>
6808 These intrinsics does a series of operations atomically. They first load the
6809 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6810 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6811 the original value stored at <tt>ptr</tt>.
6812</p>
6813
6814<h5>Examples:</h5>
6815<pre>
6816%ptr = malloc i32
6817 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6818%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6819 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6820%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6821 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6822%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6823 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6824%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6825 <i>; yields {i32}:result3 = 8</i>
6826%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6827</pre>
6828</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6829
6830<!-- ======================================================================= -->
6831<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6832 <a name="int_general">General Intrinsics</a>
6833</div>
6834
6835<div class="doc_text">
6836<p> This class of intrinsics is designed to be generic and has
6837no specific purpose. </p>
6838</div>
6839
6840<!-- _______________________________________________________________________ -->
6841<div class="doc_subsubsection">
6842 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6843</div>
6844
6845<div class="doc_text">
6846
6847<h5>Syntax:</h5>
6848<pre>
6849 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6850</pre>
6851
6852<h5>Overview:</h5>
6853
6854<p>
6855The '<tt>llvm.var.annotation</tt>' intrinsic
6856</p>
6857
6858<h5>Arguments:</h5>
6859
6860<p>
6861The first argument is a pointer to a value, the second is a pointer to a
6862global string, the third is a pointer to a global string which is the source
6863file name, and the last argument is the line number.
6864</p>
6865
6866<h5>Semantics:</h5>
6867
6868<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6869This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6870This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6871annotations. These have no other defined use, they are ignored by code
6872generation and optimization.
6873</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6874</div>
6875
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6876<!-- _______________________________________________________________________ -->
6877<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6878 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6879</div>
6880
6881<div class="doc_text">
6882
6883<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6884<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6885any integer bit width.
6886</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6887<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6888 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6889 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6890 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6891 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6892 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]6893</pre>
6894
6895<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6896
6897<p>
6898The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6899</p>
6900
6901<h5>Arguments:</h5>
6902
6903<p>
6904The first argument is an integer value (result of some expression),
6905the second is a pointer to a global string, the third is a pointer to a global
6906string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6907It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6908</p>
6909
6910<h5>Semantics:</h5>
6911
6912<p>
6913This intrinsic allows annotations to be put on arbitrary expressions
6914with arbitrary strings. This can be useful for special purpose optimizations
6915that want to look for these annotations. These have no other defined use, they
6916are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6917</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6918</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6919
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6920<!-- _______________________________________________________________________ -->
6921<div class="doc_subsubsection">
6922 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6923</div>
6924
6925<div class="doc_text">
6926
6927<h5>Syntax:</h5>
6928<pre>
6929 declare void @llvm.trap()
6930</pre>
6931
6932<h5>Overview:</h5>
6933
6934<p>
6935The '<tt>llvm.trap</tt>' intrinsic
6936</p>
6937
6938<h5>Arguments:</h5>
6939
6940<p>
6941None
6942</p>
6943
6944<h5>Semantics:</h5>
6945
6946<p>
6947This intrinsics is lowered to the target dependent trap instruction. If the
6948target does not have a trap instruction, this intrinsic will be lowered to the
6949call of the abort() function.
6950</p>
6951</div>
6952
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6953<!-- _______________________________________________________________________ -->
6954<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6955 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6956</div>
6957<div class="doc_text">
6958<h5>Syntax:</h5>
6959<pre>
6960declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6961
6962</pre>
6963<h5>Overview:</h5>
6964<p>
6965 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6966 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6967 it is placed on the stack before local variables.
6968</p>
6969<h5>Arguments:</h5>
6970<p>
6971 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6972 first argument is the value loaded from the stack guard
6973 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6974 has enough space to hold the value of the guard.
6975</p>
6976<h5>Semantics:</h5>
6977<p>
6978 This intrinsic causes the prologue/epilogue inserter to force the position of
6979 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6980 stack. This is to ensure that if a local variable on the stack is overwritten,
6981 it will destroy the value of the guard. When the function exits, the guard on
6982 the stack is checked against the original guard. If they're different, then
6983 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6984</p>
6985</div>
6986
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6987<!-- *********************************************************************** -->
6988<hr>
6989<address>
6990 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6991 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6992 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6993 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]6994
6995 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6996 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6997 Last modified: $Date$
6998</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6999
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7000</body>
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