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gerrit-public.fairphone.software / fp2-dev / platform / external / llvm / 48000e9d644024893c2054ea70429ddd82ea6b79 / . / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
10 <link rel="stylesheet" href="llvm.css" type="text/css">
11</head>
12
13<body>
14
15<div class="doc_title"> LLVM Language Reference Manual </div>
16<ol>
17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
23 <li><a href="#linkage">Linkage Types</a></li>
24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]25 <li><a href="#namedtypes">Named Types</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]26 <li><a href="#globalvars">Global Variables</a></li>
27 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]28 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]29 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]30 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]31 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]32 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
33 <li><a href="#datalayout">Data Layout</a></li>
34 </ol>
35 </li>
36 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]38 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]39 <li><a href="#t_primitive">Primitive Types</a>
40 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]41 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]44 <li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]45 </ol>
46 </li>
47 <li><a href="#t_derived">Derived Types</a>
48 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]49 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]50 <li><a href="#t_array">Array Type</a></li>
51 <li><a href="#t_function">Function Type</a></li>
52 <li><a href="#t_pointer">Pointer Type</a></li>
53 <li><a href="#t_struct">Structure Type</a></li>
54 <li><a href="#t_pstruct">Packed Structure Type</a></li>
55 <li><a href="#t_vector">Vector Type</a></li>
56 <li><a href="#t_opaque">Opaque Type</a></li>
57 </ol>
58 </li>
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]59 <li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]60 </ol>
61 </li>
62 <li><a href="#constants">Constants</a>
63 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]64 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]65 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]66 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
67 <li><a href="#undefvalues">Undefined Values</a></li>
68 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]69 <li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]70 </ol>
71 </li>
72 <li><a href="#othervalues">Other Values</a>
73 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]74 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]75 </ol>
76 </li>
77 <li><a href="#instref">Instruction Reference</a>
78 <ol>
79 <li><a href="#terminators">Terminator Instructions</a>
80 <ol>
81 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
82 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
83 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
84 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
85 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
86 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
87 </ol>
88 </li>
89 <li><a href="#binaryops">Binary Operations</a>
90 <ol>
91 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]92 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]93 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]94 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]95 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]96 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]97 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
98 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
99 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
100 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
101 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
102 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
103 </ol>
104 </li>
105 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
106 <ol>
107 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
108 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
109 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
110 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
111 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
112 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
113 </ol>
114 </li>
115 <li><a href="#vectorops">Vector Operations</a>
116 <ol>
117 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
118 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
119 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
120 </ol>
121 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]122 <li><a href="#aggregateops">Aggregate Operations</a>
123 <ol>
124 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
125 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
126 </ol>
127 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]128 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
129 <ol>
130 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
131 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
132 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
133 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
134 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
135 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
136 </ol>
137 </li>
138 <li><a href="#convertops">Conversion Operations</a>
139 <ol>
140 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
141 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
142 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
143 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
144 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
145 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
146 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
147 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
148 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
149 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
150 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
151 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
152 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]153 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]154 <li><a href="#otherops">Other Operations</a>
155 <ol>
156 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
157 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]158 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
159 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]160 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
161 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
162 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
163 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
164 </ol>
165 </li>
166 </ol>
167 </li>
168 <li><a href="#intrinsics">Intrinsic Functions</a>
169 <ol>
170 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
171 <ol>
172 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
173 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
174 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
175 </ol>
176 </li>
177 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
178 <ol>
179 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
180 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
181 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
182 </ol>
183 </li>
184 <li><a href="#int_codegen">Code Generator Intrinsics</a>
185 <ol>
186 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
187 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
188 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
189 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
190 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
191 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
192 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
193 </ol>
194 </li>
195 <li><a href="#int_libc">Standard C Library Intrinsics</a>
196 <ol>
197 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
201 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]202 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
203 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
204 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]205 </ol>
206 </li>
207 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
208 <ol>
209 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
210 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
211 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
212 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
213 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
214 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
215 </ol>
216 </li>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]217 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
218 <ol>
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]219 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
220 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
221 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
222 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
223 <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]224 <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]225 </ol>
226 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]227 <li><a href="#int_debugger">Debugger intrinsics</a></li>
228 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]229 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]230 <ol>
231 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]232 </ol>
233 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]234 <li><a href="#int_atomics">Atomic intrinsics</a>
235 <ol>
236 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
237 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
238 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
239 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
240 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
241 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
242 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
243 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
244 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
245 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
246 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
247 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
248 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
249 </ol>
250 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]251 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]252 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]253 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]254 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]255 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]256 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]257 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]258 '<tt>llvm.trap</tt>' Intrinsic</a></li>
259 <li><a href="#int_stackprotector">
260 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]261 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]262 </li>
263 </ol>
264 </li>
265</ol>
266
267<div class="doc_author">
268 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
269 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
270</div>
271
272<!-- *********************************************************************** -->
273<div class="doc_section"> <a name="abstract">Abstract </a></div>
274<!-- *********************************************************************** -->
275
276<div class="doc_text">
277<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]278LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]279type safety, low-level operations, flexibility, and the capability of
280representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]281representation used throughout all phases of the LLVM compilation
282strategy.</p>
283</div>
284
285<!-- *********************************************************************** -->
286<div class="doc_section"> <a name="introduction">Introduction</a> </div>
287<!-- *********************************************************************** -->
288
289<div class="doc_text">
290
291<p>The LLVM code representation is designed to be used in three
292different forms: as an in-memory compiler IR, as an on-disk bitcode
293representation (suitable for fast loading by a Just-In-Time compiler),
294and as a human readable assembly language representation. This allows
295LLVM to provide a powerful intermediate representation for efficient
296compiler transformations and analysis, while providing a natural means
297to debug and visualize the transformations. The three different forms
298of LLVM are all equivalent. This document describes the human readable
299representation and notation.</p>
300
301<p>The LLVM representation aims to be light-weight and low-level
302while being expressive, typed, and extensible at the same time. It
303aims to be a "universal IR" of sorts, by being at a low enough level
304that high-level ideas may be cleanly mapped to it (similar to how
305microprocessors are "universal IR's", allowing many source languages to
306be mapped to them). By providing type information, LLVM can be used as
307the target of optimizations: for example, through pointer analysis, it
308can be proven that a C automatic variable is never accessed outside of
309the current function... allowing it to be promoted to a simple SSA
310value instead of a memory location.</p>
311
312</div>
313
314<!-- _______________________________________________________________________ -->
315<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
316
317<div class="doc_text">
318
319<p>It is important to note that this document describes 'well formed'
320LLVM assembly language. There is a difference between what the parser
321accepts and what is considered 'well formed'. For example, the
322following instruction is syntactically okay, but not well formed:</p>
323
324<div class="doc_code">
325<pre>
326%x = <a href="#i_add">add</a> i32 1, %x
327</pre>
328</div>
329
330<p>...because the definition of <tt>%x</tt> does not dominate all of
331its uses. The LLVM infrastructure provides a verification pass that may
332be used to verify that an LLVM module is well formed. This pass is
333automatically run by the parser after parsing input assembly and by
334the optimizer before it outputs bitcode. The violations pointed out
335by the verifier pass indicate bugs in transformation passes or input to
336the parser.</p>
337</div>
338
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]339<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]340
341<!-- *********************************************************************** -->
342<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
343<!-- *********************************************************************** -->
344
345<div class="doc_text">
346
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]347 <p>LLVM identifiers come in two basic types: global and local. Global
348 identifiers (functions, global variables) begin with the @ character. Local
349 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]350 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]351
352<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]353 <li>Named values are represented as a string of characters with their prefix.
354 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
355 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]356 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]357 with quotes. Special characters may be escaped using "\xx" where xx is the
358 ASCII code for the character in hexadecimal. In this way, any character can
359 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]360
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]361 <li>Unnamed values are represented as an unsigned numeric value with their
362 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]363
364 <li>Constants, which are described in a <a href="#constants">section about
365 constants</a>, below.</li>
366</ol>
367
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]368<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]369don't need to worry about name clashes with reserved words, and the set of
370reserved words may be expanded in the future without penalty. Additionally,
371unnamed identifiers allow a compiler to quickly come up with a temporary
372variable without having to avoid symbol table conflicts.</p>
373
374<p>Reserved words in LLVM are very similar to reserved words in other
375languages. There are keywords for different opcodes
376('<tt><a href="#i_add">add</a></tt>',
377 '<tt><a href="#i_bitcast">bitcast</a></tt>',
378 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
379href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
380and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]381none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]382
383<p>Here is an example of LLVM code to multiply the integer variable
384'<tt>%X</tt>' by 8:</p>
385
386<p>The easy way:</p>
387
388<div class="doc_code">
389<pre>
390%result = <a href="#i_mul">mul</a> i32 %X, 8
391</pre>
392</div>
393
394<p>After strength reduction:</p>
395
396<div class="doc_code">
397<pre>
398%result = <a href="#i_shl">shl</a> i32 %X, i8 3
399</pre>
400</div>
401
402<p>And the hard way:</p>
403
404<div class="doc_code">
405<pre>
406<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
407<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
408%result = <a href="#i_add">add</a> i32 %1, %1
409</pre>
410</div>
411
412<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
413important lexical features of LLVM:</p>
414
415<ol>
416
417 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
418 line.</li>
419
420 <li>Unnamed temporaries are created when the result of a computation is not
421 assigned to a named value.</li>
422
423 <li>Unnamed temporaries are numbered sequentially</li>
424
425</ol>
426
427<p>...and it also shows a convention that we follow in this document. When
428demonstrating instructions, we will follow an instruction with a comment that
429defines the type and name of value produced. Comments are shown in italic
430text.</p>
431
432</div>
433
434<!-- *********************************************************************** -->
435<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
436<!-- *********************************************************************** -->
437
438<!-- ======================================================================= -->
439<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
440</div>
441
442<div class="doc_text">
443
444<p>LLVM programs are composed of "Module"s, each of which is a
445translation unit of the input programs. Each module consists of
446functions, global variables, and symbol table entries. Modules may be
447combined together with the LLVM linker, which merges function (and
448global variable) definitions, resolves forward declarations, and merges
449symbol table entries. Here is an example of the "hello world" module:</p>
450
451<div class="doc_code">
452<pre><i>; Declare the string constant as a global constant...</i>
453<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
454 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
455
456<i>; External declaration of the puts function</i>
457<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
458
459<i>; Definition of main function</i>
460define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]461 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]462 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]463 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]464
465 <i>; Call puts function to write out the string to stdout...</i>
466 <a
467 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
468 <a
469 href="#i_ret">ret</a> i32 0<br>}<br>
470</pre>
471</div>
472
473<p>This example is made up of a <a href="#globalvars">global variable</a>
474named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
475function, and a <a href="#functionstructure">function definition</a>
476for "<tt>main</tt>".</p>
477
478<p>In general, a module is made up of a list of global values,
479where both functions and global variables are global values. Global values are
480represented by a pointer to a memory location (in this case, a pointer to an
481array of char, and a pointer to a function), and have one of the following <a
482href="#linkage">linkage types</a>.</p>
483
484</div>
485
486<!-- ======================================================================= -->
487<div class="doc_subsection">
488 <a name="linkage">Linkage Types</a>
489</div>
490
491<div class="doc_text">
492
493<p>
494All Global Variables and Functions have one of the following types of linkage:
495</p>
496
497<dl>
498
Rafael Espindolaa168fc92009-01-15 20:18:42 +0000[diff] [blame]499 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
500
501 <dd>Global values with private linkage are only directly accessible by
502 objects in the current module. In particular, linking code into a module with
503 an private global value may cause the private to be renamed as necessary to
504 avoid collisions. Because the symbol is private to the module, all
505 references can be updated. This doesn't show up in any symbol table in the
506 object file.
507 </dd>
508
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]509 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]510
Duncan Sandsa75223a2009-01-16 09:29:46 +0000[diff] [blame]511 <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]512 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]513 '<tt>static</tt>' keyword in C.
514 </dd>
515
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]516 <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
517 </dt>
518
519 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
520 into the object file corresponding to the LLVM module. They exist to
521 allow inlining and other optimizations to take place given knowledge of the
522 definition of the global, which is known to be somewhere outside the module.
523 Globals with <tt>available_externally</tt> linkage are allowed to be discarded
524 at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
525 type is only allowed on definitions, not declarations.</dd>
526
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]527 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
528
529 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
530 the same name when linkage occurs. This is typically used to implement
531 inline functions, templates, or other code which must be generated in each
532 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
533 allowed to be discarded.
534 </dd>
535
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]536 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
537
538 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
539 linkage, except that unreferenced <tt>common</tt> globals may not be
540 discarded. This is used for globals that may be emitted in multiple
541 translation units, but that are not guaranteed to be emitted into every
542 translation unit that uses them. One example of this is tentative
543 definitions in C, such as "<tt>int X;</tt>" at global scope.
544 </dd>
545
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
547
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]548 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
549 that some targets may choose to emit different assembly sequences for them
550 for target-dependent reasons. This is used for globals that are declared
551 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]552 </dd>
553
554 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
555
556 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
557 pointer to array type. When two global variables with appending linkage are
558 linked together, the two global arrays are appended together. This is the
559 LLVM, typesafe, equivalent of having the system linker append together
560 "sections" with identical names when .o files are linked.
561 </dd>
562
563 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]564
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]565 <dd>The semantics of this linkage follow the ELF object file model: the
566 symbol is weak until linked, if not linked, the symbol becomes null instead
567 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]568 </dd>
569
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]570 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]571 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]572 <dd>Some languages allow differing globals to be merged, such as two
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]573 functions with different semantics. Other languages, such as <tt>C++</tt>,
574 ensure that only equivalent globals are ever merged (the "one definition
Chris Lattner68433442009-04-13 05:44:34 +0000[diff] [blame]575 rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Duncan Sandsb95df792009-03-11 20:14:15 +0000[diff] [blame]576 and <tt>weak_odr</tt> linkage types to indicate that the global will only
577 be merged with equivalent globals. These linkage types are otherwise the
578 same as their non-<tt>odr</tt> versions.
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]579 </dd>
580
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]581 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
582
583 <dd>If none of the above identifiers are used, the global is externally
584 visible, meaning that it participates in linkage and can be used to resolve
585 external symbol references.
586 </dd>
587</dl>
588
589 <p>
590 The next two types of linkage are targeted for Microsoft Windows platform
591 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]592 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]593 </p>
594
595 <dl>
596 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
597
598 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
599 or variable via a global pointer to a pointer that is set up by the DLL
600 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]601 formed by combining <code>__imp_</code> and the function or variable name.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]602 </dd>
603
604 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
605
606 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
607 pointer to a pointer in a DLL, so that it can be referenced with the
608 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman5ec99832009-01-12 21:35:55 +0000[diff] [blame]609 name is formed by combining <code>__imp_</code> and the function or variable
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]610 name.
611 </dd>
612
613</dl>
614
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]615<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]616variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
617variable and was linked with this one, one of the two would be renamed,
618preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
619external (i.e., lacking any linkage declarations), they are accessible
620outside of the current module.</p>
621<p>It is illegal for a function <i>declaration</i>
Duncan Sands565f65d2009-03-11 08:08:06 +0000[diff] [blame]622to have any linkage type other than "externally visible", <tt>dllimport</tt>
623or <tt>extern_weak</tt>.</p>
Duncan Sands19d161f2009-03-07 15:45:40 +0000[diff] [blame]624<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
625or <tt>weak_odr</tt> linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]626</div>
627
628<!-- ======================================================================= -->
629<div class="doc_subsection">
630 <a name="callingconv">Calling Conventions</a>
631</div>
632
633<div class="doc_text">
634
635<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
636and <a href="#i_invoke">invokes</a> can all have an optional calling convention
637specified for the call. The calling convention of any pair of dynamic
638caller/callee must match, or the behavior of the program is undefined. The
639following calling conventions are supported by LLVM, and more may be added in
640the future:</p>
641
642<dl>
643 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
644
645 <dd>This calling convention (the default if no other calling convention is
646 specified) matches the target C calling conventions. This calling convention
647 supports varargs function calls and tolerates some mismatch in the declared
648 prototype and implemented declaration of the function (as does normal C).
649 </dd>
650
651 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
652
653 <dd>This calling convention attempts to make calls as fast as possible
654 (e.g. by passing things in registers). This calling convention allows the
655 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]656 without having to conform to an externally specified ABI (Application Binary
657 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]658 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
659 supported. This calling convention does not support varargs and requires the
660 prototype of all callees to exactly match the prototype of the function
661 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]662 </dd>
663
664 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
665
666 <dd>This calling convention attempts to make code in the caller as efficient
667 as possible under the assumption that the call is not commonly executed. As
668 such, these calls often preserve all registers so that the call does not break
669 any live ranges in the caller side. This calling convention does not support
670 varargs and requires the prototype of all callees to exactly match the
671 prototype of the function definition.
672 </dd>
673
674 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
675
676 <dd>Any calling convention may be specified by number, allowing
677 target-specific calling conventions to be used. Target specific calling
678 conventions start at 64.
679 </dd>
680</dl>
681
682<p>More calling conventions can be added/defined on an as-needed basis, to
683support pascal conventions or any other well-known target-independent
684convention.</p>
685
686</div>
687
688<!-- ======================================================================= -->
689<div class="doc_subsection">
690 <a name="visibility">Visibility Styles</a>
691</div>
692
693<div class="doc_text">
694
695<p>
696All Global Variables and Functions have one of the following visibility styles:
697</p>
698
699<dl>
700 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
701
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]702 <dd>On targets that use the ELF object file format, default visibility means
703 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]704 modules and, in shared libraries, means that the declared entity may be
705 overridden. On Darwin, default visibility means that the declaration is
706 visible to other modules. Default visibility corresponds to "external
707 linkage" in the language.
708 </dd>
709
710 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
711
712 <dd>Two declarations of an object with hidden visibility refer to the same
713 object if they are in the same shared object. Usually, hidden visibility
714 indicates that the symbol will not be placed into the dynamic symbol table,
715 so no other module (executable or shared library) can reference it
716 directly.
717 </dd>
718
719 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
720
721 <dd>On ELF, protected visibility indicates that the symbol will be placed in
722 the dynamic symbol table, but that references within the defining module will
723 bind to the local symbol. That is, the symbol cannot be overridden by another
724 module.
725 </dd>
726</dl>
727
728</div>
729
730<!-- ======================================================================= -->
731<div class="doc_subsection">
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]732 <a name="namedtypes">Named Types</a>
733</div>
734
735<div class="doc_text">
736
737<p>LLVM IR allows you to specify name aliases for certain types. This can make
738it easier to read the IR and make the IR more condensed (particularly when
739recursive types are involved). An example of a name specification is:
740</p>
741
742<div class="doc_code">
743<pre>
744%mytype = type { %mytype*, i32 }
745</pre>
746</div>
747
748<p>You may give a name to any <a href="#typesystem">type</a> except "<a
749href="t_void">void</a>". Type name aliases may be used anywhere a type is
750expected with the syntax "%mytype".</p>
751
752<p>Note that type names are aliases for the structural type that they indicate,
753and that you can therefore specify multiple names for the same type. This often
754leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
755structural typing, the name is not part of the type. When printing out LLVM IR,
756the printer will pick <em>one name</em> to render all types of a particular
757shape. This means that if you have code where two different source types end up
758having the same LLVM type, that the dumper will sometimes print the "wrong" or
759unexpected type. This is an important design point and isn't going to
760change.</p>
761
762</div>
763
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]764<!-- ======================================================================= -->
765<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]766 <a name="globalvars">Global Variables</a>
767</div>
768
769<div class="doc_text">
770
771<p>Global variables define regions of memory allocated at compilation time
772instead of run-time. Global variables may optionally be initialized, may have
773an explicit section to be placed in, and may have an optional explicit alignment
774specified. A variable may be defined as "thread_local", which means that it
775will not be shared by threads (each thread will have a separated copy of the
776variable). A variable may be defined as a global "constant," which indicates
777that the contents of the variable will <b>never</b> be modified (enabling better
778optimization, allowing the global data to be placed in the read-only section of
779an executable, etc). Note that variables that need runtime initialization
780cannot be marked "constant" as there is a store to the variable.</p>
781
782<p>
783LLVM explicitly allows <em>declarations</em> of global variables to be marked
784constant, even if the final definition of the global is not. This capability
785can be used to enable slightly better optimization of the program, but requires
786the language definition to guarantee that optimizations based on the
787'constantness' are valid for the translation units that do not include the
788definition.
789</p>
790
791<p>As SSA values, global variables define pointer values that are in
792scope (i.e. they dominate) all basic blocks in the program. Global
793variables always define a pointer to their "content" type because they
794describe a region of memory, and all memory objects in LLVM are
795accessed through pointers.</p>
796
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]797<p>A global variable may be declared to reside in a target-specifc numbered
798address space. For targets that support them, address spaces may affect how
799optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]800the variable. The default address space is zero. The address space qualifier
801must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803<p>LLVM allows an explicit section to be specified for globals. If the target
804supports it, it will emit globals to the section specified.</p>
805
806<p>An explicit alignment may be specified for a global. If not present, or if
807the alignment is set to zero, the alignment of the global is set by the target
808to whatever it feels convenient. If an explicit alignment is specified, the
809global is forced to have at least that much alignment. All alignments must be
810a power of 2.</p>
811
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]812<p>For example, the following defines a global in a numbered address space with
813an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814
815<div class="doc_code">
816<pre>
Dan Gohman21ef02c2009-01-11 00:40:00 +0000[diff] [blame]817@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]818</pre>
819</div>
820
821</div>
822
823
824<!-- ======================================================================= -->
825<div class="doc_subsection">
826 <a name="functionstructure">Functions</a>
827</div>
828
829<div class="doc_text">
830
831<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
832an optional <a href="#linkage">linkage type</a>, an optional
833<a href="#visibility">visibility style</a>, an optional
834<a href="#callingconv">calling convention</a>, a return type, an optional
835<a href="#paramattrs">parameter attribute</a> for the return type, a function
836name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]837<a href="#paramattrs">parameter attributes</a>), optional
838<a href="#fnattrs">function attributes</a>, an optional section,
839an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]840an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]841
842LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
843optional <a href="#linkage">linkage type</a>, an optional
844<a href="#visibility">visibility style</a>, an optional
845<a href="#callingconv">calling convention</a>, a return type, an optional
846<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]847name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]848<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]849
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]850<p>A function definition contains a list of basic blocks, forming the CFG
851(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]852the function. Each basic block may optionally start with a label (giving the
853basic block a symbol table entry), contains a list of instructions, and ends
854with a <a href="#terminators">terminator</a> instruction (such as a branch or
855function return).</p>
856
857<p>The first basic block in a function is special in two ways: it is immediately
858executed on entrance to the function, and it is not allowed to have predecessor
859basic blocks (i.e. there can not be any branches to the entry block of a
860function). Because the block can have no predecessors, it also cannot have any
861<a href="#i_phi">PHI nodes</a>.</p>
862
863<p>LLVM allows an explicit section to be specified for functions. If the target
864supports it, it will emit functions to the section specified.</p>
865
866<p>An explicit alignment may be specified for a function. If not present, or if
867the alignment is set to zero, the alignment of the function is set by the target
868to whatever it feels convenient. If an explicit alignment is specified, the
869function is forced to have at least that much alignment. All alignments must be
870a power of 2.</p>
871
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]872 <h5>Syntax:</h5>
873
874<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]875<tt>
876define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
877 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
878 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
879 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
880 [<a href="#gc">gc</a>] { ... }
881</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]882</div>
883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884</div>
885
886
887<!-- ======================================================================= -->
888<div class="doc_subsection">
889 <a name="aliasstructure">Aliases</a>
890</div>
891<div class="doc_text">
892 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]893 function, global variable, another alias or bitcast of global value). Aliases
894 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]895 optional <a href="#visibility">visibility style</a>.</p>
896
897 <h5>Syntax:</h5>
898
899<div class="doc_code">
900<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]901@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]902</pre>
903</div>
904
905</div>
906
907
908
909<!-- ======================================================================= -->
910<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
911<div class="doc_text">
912 <p>The return type and each parameter of a function type may have a set of
913 <i>parameter attributes</i> associated with them. Parameter attributes are
914 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]915 a function. Parameter attributes are considered to be part of the function,
916 not of the function type, so functions with different parameter attributes
917 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]918
919 <p>Parameter attributes are simple keywords that follow the type specified. If
920 multiple parameter attributes are needed, they are space separated. For
921 example:</p>
922
923<div class="doc_code">
924<pre>
Nick Lewycky3022a742009-02-15 23:06:14 +0000[diff] [blame]925declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]926declare i32 @atoi(i8 zeroext)
927declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]928</pre>
929</div>
930
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]931 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
932 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]933
934 <p>Currently, only the following parameter attributes are defined:</p>
935 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]936 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]937 <dd>This indicates to the code generator that the parameter or return value
938 should be zero-extended to a 32-bit value by the caller (for a parameter)
939 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]940
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]941 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]942 <dd>This indicates to the code generator that the parameter or return value
943 should be sign-extended to a 32-bit value by the caller (for a parameter)
944 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]946 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]947 <dd>This indicates that this parameter or return value should be treated
948 in a special target-dependent fashion during while emitting code for a
949 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]950 to memory, though some targets use it to distinguish between two different
951 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]952
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]953 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]954 <dd>This indicates that the pointer parameter should really be passed by
955 value to the function. The attribute implies that a hidden copy of the
956 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]957 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]958 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]959 value, but is also valid on pointers to scalars. The copy is considered to
960 belong to the caller not the callee (for example,
961 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]962 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnere39c5bf2009-02-05 05:42:28 +0000[diff] [blame]963 values. The byval attribute also supports specifying an alignment with the
964 align attribute. This has a target-specific effect on the code generator
965 that usually indicates a desired alignment for the synthesized stack
966 slot.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]968 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]969 <dd>This indicates that the pointer parameter specifies the address of a
970 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]971 This pointer must be guaranteed by the caller to be valid: loads and stores
972 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]973 be applied to the first parameter. This is not a valid attribute for
974 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]975
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]976 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]977 <dd>This indicates that the pointer does not alias any global or any other
978 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]979 case. On a function return value, <tt>noalias</tt> additionally indicates
980 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]981 caller. For further details, please see the discussion of the NoAlias
982 response in
983 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
984 analysis</a>.</dd>
985
986 <dt><tt>nocapture</tt></dt>
987 <dd>This indicates that the callee does not make any copies of the pointer
988 that outlive the callee itself. This is not a valid attribute for return
989 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]990
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]991 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]992 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]993 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
994 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]995 </dl>
996
997</div>
998
999<!-- ======================================================================= -->
1000<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]1001 <a name="gc">Garbage Collector Names</a>
1002</div>
1003
1004<div class="doc_text">
1005<p>Each function may specify a garbage collector name, which is simply a
1006string.</p>
1007
1008<div class="doc_code"><pre
1009>define void @f() gc "name" { ...</pre></div>
1010
1011<p>The compiler declares the supported values of <i>name</i>. Specifying a
1012collector which will cause the compiler to alter its output in order to support
1013the named garbage collection algorithm.</p>
1014</div>
1015
1016<!-- ======================================================================= -->
1017<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1018 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1019</div>
1020
1021<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1022
1023<p>Function attributes are set to communicate additional information about
1024 a function. Function attributes are considered to be part of the function,
1025 not of the function type, so functions with different parameter attributes
1026 can have the same function type.</p>
1027
1028 <p>Function attributes are simple keywords that follow the type specified. If
1029 multiple attributes are needed, they are space separated. For
1030 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1031
1032<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1033<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1034define void @f() noinline { ... }
1035define void @f() alwaysinline { ... }
1036define void @f() alwaysinline optsize { ... }
1037define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1038</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1039</div>
1040
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1041<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1042<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1043<dd>This attribute indicates that the inliner should attempt to inline this
1044function into callers whenever possible, ignoring any active inlining size
1045threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1046
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1047<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1048<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]1049in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1050<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1051
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1052<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]1053<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1054make choices that keep the code size of this function low, and otherwise do
1055optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1056
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1057<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1058<dd>This function attribute indicates that the function never returns normally.
1059This produces undefined behavior at runtime if the function ever does
1060dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1061
1062<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]1063<dd>This function attribute indicates that the function never returns with an
1064unwind or exceptional control flow. If the function does unwind, its runtime
1065behavior is undefined.</dd>
1066
1067<dt><tt>readnone</tt></dt>
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1068<dd>This attribute indicates that the function computes its result (or decides to
1069unwind an exception) based strictly on its arguments, without dereferencing any
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1070pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1071registers, etc) visible to caller functions. It does not write through any
1072pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1073never changes any state visible to callers. This means that it cannot unwind
1074exceptions by calling the <tt>C++</tt> exception throwing methods, but could
1075use the <tt>unwind</tt> instruction.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]1076
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]1077<dt><tt><a name="readonly">readonly</a></tt></dt>
1078<dd>This attribute indicates that the function does not write through any
1079pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1080or otherwise modify any state (e.g. memory, control registers, etc) visible to
1081caller functions. It may dereference pointer arguments and read state that may
Duncan Sands2f500832009-05-06 06:49:50 +0000[diff] [blame]1082be set in the caller. A readonly function always returns the same value (or
1083unwinds an exception identically) when called with the same set of arguments
1084and global state. It cannot unwind an exception by calling the <tt>C++</tt>
1085exception throwing methods, but may use the <tt>unwind</tt> instruction.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1086
1087<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1088<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1089protector. It is in the form of a "canary"&mdash;a random value placed on the
1090stack before the local variables that's checked upon return from the function to
1091see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1092needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1093
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1094<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1095that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1096have an <tt>ssp</tt> attribute.</p></dd>
1097
1098<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1099<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1100stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1101function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1102
1103<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1104function that doesn't have an <tt>sspreq</tt> attribute or which has
1105an <tt>ssp</tt> attribute, then the resulting function will have
1106an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1107</dl>
1108
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1109</div>
1110
1111<!-- ======================================================================= -->
1112<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1113 <a name="moduleasm">Module-Level Inline Assembly</a>
1114</div>
1115
1116<div class="doc_text">
1117<p>
1118Modules may contain "module-level inline asm" blocks, which corresponds to the
1119GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1120LLVM and treated as a single unit, but may be separated in the .ll file if
1121desired. The syntax is very simple:
1122</p>
1123
1124<div class="doc_code">
1125<pre>
1126module asm "inline asm code goes here"
1127module asm "more can go here"
1128</pre>
1129</div>
1130
1131<p>The strings can contain any character by escaping non-printable characters.
1132 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1133 for the number.
1134</p>
1135
1136<p>
1137 The inline asm code is simply printed to the machine code .s file when
1138 assembly code is generated.
1139</p>
1140</div>
1141
1142<!-- ======================================================================= -->
1143<div class="doc_subsection">
1144 <a name="datalayout">Data Layout</a>
1145</div>
1146
1147<div class="doc_text">
1148<p>A module may specify a target specific data layout string that specifies how
1149data is to be laid out in memory. The syntax for the data layout is simply:</p>
1150<pre> target datalayout = "<i>layout specification</i>"</pre>
1151<p>The <i>layout specification</i> consists of a list of specifications
1152separated by the minus sign character ('-'). Each specification starts with a
1153letter and may include other information after the letter to define some
1154aspect of the data layout. The specifications accepted are as follows: </p>
1155<dl>
1156 <dt><tt>E</tt></dt>
1157 <dd>Specifies that the target lays out data in big-endian form. That is, the
1158 bits with the most significance have the lowest address location.</dd>
1159 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1160 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1161 the bits with the least significance have the lowest address location.</dd>
1162 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1163 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1164 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1165 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1166 too.</dd>
1167 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1168 <dd>This specifies the alignment for an integer type of a given bit
1169 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1170 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1171 <dd>This specifies the alignment for a vector type of a given bit
1172 <i>size</i>.</dd>
1173 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1174 <dd>This specifies the alignment for a floating point type of a given bit
1175 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1176 (double).</dd>
1177 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1178 <dd>This specifies the alignment for an aggregate type of a given bit
1179 <i>size</i>.</dd>
1180</dl>
1181<p>When constructing the data layout for a given target, LLVM starts with a
1182default set of specifications which are then (possibly) overriden by the
1183specifications in the <tt>datalayout</tt> keyword. The default specifications
1184are given in this list:</p>
1185<ul>
1186 <li><tt>E</tt> - big endian</li>
1187 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1188 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1189 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1190 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1191 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1192 <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]1193 alignment of 64-bits</li>
1194 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1195 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1196 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1197 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1198 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1199</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1200<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1201following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1202<ol>
1203 <li>If the type sought is an exact match for one of the specifications, that
1204 specification is used.</li>
1205 <li>If no match is found, and the type sought is an integer type, then the
1206 smallest integer type that is larger than the bitwidth of the sought type is
1207 used. If none of the specifications are larger than the bitwidth then the the
1208 largest integer type is used. For example, given the default specifications
1209 above, the i7 type will use the alignment of i8 (next largest) while both
1210 i65 and i256 will use the alignment of i64 (largest specified).</li>
1211 <li>If no match is found, and the type sought is a vector type, then the
1212 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1213 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1214 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1215</ol>
1216</div>
1217
1218<!-- *********************************************************************** -->
1219<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1220<!-- *********************************************************************** -->
1221
1222<div class="doc_text">
1223
1224<p>The LLVM type system is one of the most important features of the
1225intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1226optimizations to be performed on the intermediate representation directly,
1227without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1228extra analyses on the side before the transformation. A strong type
1229system makes it easier to read the generated code and enables novel
1230analyses and transformations that are not feasible to perform on normal
1231three address code representations.</p>
1232
1233</div>
1234
1235<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1236<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1237Classifications</a> </div>
1238<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1239<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1240classifications:</p>
1241
1242<table border="1" cellspacing="0" cellpadding="4">
1243 <tbody>
1244 <tr><th>Classification</th><th>Types</th></tr>
1245 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1246 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1247 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1248 </tr>
1249 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1250 <td><a href="#t_floating">floating point</a></td>
1251 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252 </tr>
1253 <tr>
1254 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1255 <td><a href="#t_integer">integer</a>,
1256 <a href="#t_floating">floating point</a>,
1257 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1258 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1259 <a href="#t_struct">structure</a>,
1260 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1261 <a href="#t_label">label</a>,
1262 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1263 </td>
1264 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1265 <tr>
1266 <td><a href="#t_primitive">primitive</a></td>
1267 <td><a href="#t_label">label</a>,
1268 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1269 <a href="#t_floating">floating point</a>,
1270 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1271 </tr>
1272 <tr>
1273 <td><a href="#t_derived">derived</a></td>
1274 <td><a href="#t_integer">integer</a>,
1275 <a href="#t_array">array</a>,
1276 <a href="#t_function">function</a>,
1277 <a href="#t_pointer">pointer</a>,
1278 <a href="#t_struct">structure</a>,
1279 <a href="#t_pstruct">packed structure</a>,
1280 <a href="#t_vector">vector</a>,
1281 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1282 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1283 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1284 </tbody>
1285</table>
1286
1287<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1288most important. Values of these types are the only ones which can be
1289produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1290instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1291</div>
1292
1293<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1294<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1295
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1296<div class="doc_text">
1297<p>The primitive types are the fundamental building blocks of the LLVM
1298system.</p>
1299
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1300</div>
1301
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1302<!-- _______________________________________________________________________ -->
1303<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1304
1305<div class="doc_text">
1306 <table>
1307 <tbody>
1308 <tr><th>Type</th><th>Description</th></tr>
1309 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1310 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1311 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1312 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1313 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1314 </tbody>
1315 </table>
1316</div>
1317
1318<!-- _______________________________________________________________________ -->
1319<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1320
1321<div class="doc_text">
1322<h5>Overview:</h5>
1323<p>The void type does not represent any value and has no size.</p>
1324
1325<h5>Syntax:</h5>
1326
1327<pre>
1328 void
1329</pre>
1330</div>
1331
1332<!-- _______________________________________________________________________ -->
1333<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1334
1335<div class="doc_text">
1336<h5>Overview:</h5>
1337<p>The label type represents code labels.</p>
1338
1339<h5>Syntax:</h5>
1340
1341<pre>
1342 label
1343</pre>
1344</div>
1345
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1346<!-- _______________________________________________________________________ -->
1347<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1348
1349<div class="doc_text">
1350<h5>Overview:</h5>
1351<p>The metadata type represents embedded metadata. The only derived type that
1352may contain metadata is <tt>metadata*</tt> or a function type that returns or
1353takes metadata typed parameters, but not pointer to metadata types.</p>
1354
1355<h5>Syntax:</h5>
1356
1357<pre>
1358 metadata
1359</pre>
1360</div>
1361
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1362
1363<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1364<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1365
1366<div class="doc_text">
1367
1368<p>The real power in LLVM comes from the derived types in the system.
1369This is what allows a programmer to represent arrays, functions,
1370pointers, and other useful types. Note that these derived types may be
1371recursive: For example, it is possible to have a two dimensional array.</p>
1372
1373</div>
1374
1375<!-- _______________________________________________________________________ -->
1376<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1377
1378<div class="doc_text">
1379
1380<h5>Overview:</h5>
1381<p>The integer type is a very simple derived type that simply specifies an
1382arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13832^23-1 (about 8 million) can be specified.</p>
1384
1385<h5>Syntax:</h5>
1386
1387<pre>
1388 iN
1389</pre>
1390
1391<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1392value.</p>
1393
1394<h5>Examples:</h5>
1395<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1396 <tr class="layout">
1397 <td class="left"><tt>i1</tt></td>
1398 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1399 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1400 <tr class="layout">
1401 <td class="left"><tt>i32</tt></td>
1402 <td class="left">a 32-bit integer.</td>
1403 </tr>
1404 <tr class="layout">
1405 <td class="left"><tt>i1942652</tt></td>
1406 <td class="left">a really big integer of over 1 million bits.</td>
1407 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1408</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1409
1410<p>Note that the code generator does not yet support large integer types
1411to be used as function return types. The specific limit on how large a
1412return type the code generator can currently handle is target-dependent;
1413currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1414targets.</p>
1415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1416</div>
1417
1418<!-- _______________________________________________________________________ -->
1419<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1420
1421<div class="doc_text">
1422
1423<h5>Overview:</h5>
1424
1425<p>The array type is a very simple derived type that arranges elements
1426sequentially in memory. The array type requires a size (number of
1427elements) and an underlying data type.</p>
1428
1429<h5>Syntax:</h5>
1430
1431<pre>
1432 [&lt;# elements&gt; x &lt;elementtype&gt;]
1433</pre>
1434
1435<p>The number of elements is a constant integer value; elementtype may
1436be any type with a size.</p>
1437
1438<h5>Examples:</h5>
1439<table class="layout">
1440 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1441 <td class="left"><tt>[40 x i32]</tt></td>
1442 <td class="left">Array of 40 32-bit integer values.</td>
1443 </tr>
1444 <tr class="layout">
1445 <td class="left"><tt>[41 x i32]</tt></td>
1446 <td class="left">Array of 41 32-bit integer values.</td>
1447 </tr>
1448 <tr class="layout">
1449 <td class="left"><tt>[4 x i8]</tt></td>
1450 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1451 </tr>
1452</table>
1453<p>Here are some examples of multidimensional arrays:</p>
1454<table class="layout">
1455 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1456 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1457 <td class="left">3x4 array of 32-bit integer values.</td>
1458 </tr>
1459 <tr class="layout">
1460 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1461 <td class="left">12x10 array of single precision floating point values.</td>
1462 </tr>
1463 <tr class="layout">
1464 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1465 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1466 </tr>
1467</table>
1468
1469<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1470length array. Normally, accesses past the end of an array are undefined in
1471LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1472As a special case, however, zero length arrays are recognized to be variable
1473length. This allows implementation of 'pascal style arrays' with the LLVM
1474type "{ i32, [0 x float]}", for example.</p>
1475
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1476<p>Note that the code generator does not yet support large aggregate types
1477to be used as function return types. The specific limit on how large an
1478aggregate return type the code generator can currently handle is
1479target-dependent, and also dependent on the aggregate element types.</p>
1480
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1481</div>
1482
1483<!-- _______________________________________________________________________ -->
1484<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1485<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1486
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1487<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1488
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1489<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1490consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1491return 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]1492If 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]1493class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1495<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1496
1497<pre>
1498 &lt;returntype list&gt; (&lt;parameter list&gt;)
1499</pre>
1500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1501<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1502specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1503which indicates that the function takes a variable number of arguments.
1504Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1505 href="#int_varargs">variable argument handling intrinsic</a> functions.
1506'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1507<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1509<h5>Examples:</h5>
1510<table class="layout">
1511 <tr class="layout">
1512 <td class="left"><tt>i32 (i32)</tt></td>
1513 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1514 </td>
1515 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1516 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1517 </tt></td>
1518 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1519 an <tt>i16</tt> that should be sign extended and a
1520 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1521 <tt>float</tt>.
1522 </td>
1523 </tr><tr class="layout">
1524 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1525 <td class="left">A vararg function that takes at least one
1526 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1527 which returns an integer. This is the signature for <tt>printf</tt> in
1528 LLVM.
1529 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1530 </tr><tr class="layout">
1531 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1532 <td class="left">A function taking an <tt>i32</tt>, returning two
1533 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1534 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1535 </tr>
1536</table>
1537
1538</div>
1539<!-- _______________________________________________________________________ -->
1540<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1541<div class="doc_text">
1542<h5>Overview:</h5>
1543<p>The structure type is used to represent a collection of data members
1544together in memory. The packing of the field types is defined to match
1545the ABI of the underlying processor. The elements of a structure may
1546be any type that has a size.</p>
1547<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1548and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1549field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1550instruction.</p>
1551<h5>Syntax:</h5>
1552<pre> { &lt;type list&gt; }<br></pre>
1553<h5>Examples:</h5>
1554<table class="layout">
1555 <tr class="layout">
1556 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1557 <td class="left">A triple of three <tt>i32</tt> values</td>
1558 </tr><tr class="layout">
1559 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1560 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1561 second element is a <a href="#t_pointer">pointer</a> to a
1562 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1563 an <tt>i32</tt>.</td>
1564 </tr>
1565</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1566
1567<p>Note that the code generator does not yet support large aggregate types
1568to be used as function return types. The specific limit on how large an
1569aggregate return type the code generator can currently handle is
1570target-dependent, and also dependent on the aggregate element types.</p>
1571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1572</div>
1573
1574<!-- _______________________________________________________________________ -->
1575<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1576</div>
1577<div class="doc_text">
1578<h5>Overview:</h5>
1579<p>The packed structure type is used to represent a collection of data members
1580together in memory. There is no padding between fields. Further, the alignment
1581of a packed structure is 1 byte. The elements of a packed structure may
1582be any type that has a size.</p>
1583<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1584and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1585field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1586instruction.</p>
1587<h5>Syntax:</h5>
1588<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1589<h5>Examples:</h5>
1590<table class="layout">
1591 <tr class="layout">
1592 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1593 <td class="left">A triple of three <tt>i32</tt> values</td>
1594 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1595 <td class="left">
1596<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1597 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1598 second element is a <a href="#t_pointer">pointer</a> to a
1599 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1600 an <tt>i32</tt>.</td>
1601 </tr>
1602</table>
1603</div>
1604
1605<!-- _______________________________________________________________________ -->
1606<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1607<div class="doc_text">
1608<h5>Overview:</h5>
1609<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1610reference to another object, which must live in memory. Pointer types may have
1611an optional address space attribute defining the target-specific numbered
1612address space where the pointed-to object resides. The default address space is
1613zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1614
1615<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]1616it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1618<h5>Syntax:</h5>
1619<pre> &lt;type&gt; *<br></pre>
1620<h5>Examples:</h5>
1621<table class="layout">
1622 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1623 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1624 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1625 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1626 </tr>
1627 <tr class="layout">
1628 <td class="left"><tt>i32 (i32 *) *</tt></td>
1629 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1631 <tt>i32</tt>.</td>
1632 </tr>
1633 <tr class="layout">
1634 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1635 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1636 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1637 </tr>
1638</table>
1639</div>
1640
1641<!-- _______________________________________________________________________ -->
1642<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1643<div class="doc_text">
1644
1645<h5>Overview:</h5>
1646
1647<p>A vector type is a simple derived type that represents a vector
1648of elements. Vector types are used when multiple primitive data
1649are operated in parallel using a single instruction (SIMD).
1650A vector type requires a size (number of
1651elements) and an underlying primitive data type. Vectors must have a power
1652of two length (1, 2, 4, 8, 16 ...). Vector types are
1653considered <a href="#t_firstclass">first class</a>.</p>
1654
1655<h5>Syntax:</h5>
1656
1657<pre>
1658 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1659</pre>
1660
1661<p>The number of elements is a constant integer value; elementtype may
1662be any integer or floating point type.</p>
1663
1664<h5>Examples:</h5>
1665
1666<table class="layout">
1667 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1668 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1669 <td class="left">Vector of 4 32-bit integer values.</td>
1670 </tr>
1671 <tr class="layout">
1672 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1673 <td class="left">Vector of 8 32-bit floating-point values.</td>
1674 </tr>
1675 <tr class="layout">
1676 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1677 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1678 </tr>
1679</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1680
1681<p>Note that the code generator does not yet support large vector types
1682to be used as function return types. The specific limit on how large a
1683vector return type codegen can currently handle is target-dependent;
1684currently it's often a few times longer than a hardware vector register.</p>
1685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1686</div>
1687
1688<!-- _______________________________________________________________________ -->
1689<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1690<div class="doc_text">
1691
1692<h5>Overview:</h5>
1693
1694<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1695corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1696In LLVM, opaque types can eventually be resolved to any type (not just a
1697structure type).</p>
1698
1699<h5>Syntax:</h5>
1700
1701<pre>
1702 opaque
1703</pre>
1704
1705<h5>Examples:</h5>
1706
1707<table class="layout">
1708 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1709 <td class="left"><tt>opaque</tt></td>
1710 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1711 </tr>
1712</table>
1713</div>
1714
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1715<!-- ======================================================================= -->
1716<div class="doc_subsection">
1717 <a name="t_uprefs">Type Up-references</a>
1718</div>
1719
1720<div class="doc_text">
1721<h5>Overview:</h5>
1722<p>
1723An "up reference" allows you to refer to a lexically enclosing type without
1724requiring it to have a name. For instance, a structure declaration may contain a
1725pointer to any of the types it is lexically a member of. Example of up
1726references (with their equivalent as named type declarations) include:</p>
1727
1728<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1729 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1730 { \2 }* %y = type { %y }*
1731 \1* %z = type %z*
1732</pre>
1733
1734<p>
1735An up reference is needed by the asmprinter for printing out cyclic types when
1736there is no declared name for a type in the cycle. Because the asmprinter does
1737not want to print out an infinite type string, it needs a syntax to handle
1738recursive types that have no names (all names are optional in llvm IR).
1739</p>
1740
1741<h5>Syntax:</h5>
1742<pre>
1743 \&lt;level&gt;
1744</pre>
1745
1746<p>
1747The level is the count of the lexical type that is being referred to.
1748</p>
1749
1750<h5>Examples:</h5>
1751
1752<table class="layout">
1753 <tr class="layout">
1754 <td class="left"><tt>\1*</tt></td>
1755 <td class="left">Self-referential pointer.</td>
1756 </tr>
1757 <tr class="layout">
1758 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1759 <td class="left">Recursive structure where the upref refers to the out-most
1760 structure.</td>
1761 </tr>
1762</table>
1763</div>
1764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1765
1766<!-- *********************************************************************** -->
1767<div class="doc_section"> <a name="constants">Constants</a> </div>
1768<!-- *********************************************************************** -->
1769
1770<div class="doc_text">
1771
1772<p>LLVM has several different basic types of constants. This section describes
1773them all and their syntax.</p>
1774
1775</div>
1776
1777<!-- ======================================================================= -->
1778<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1779
1780<div class="doc_text">
1781
1782<dl>
1783 <dt><b>Boolean constants</b></dt>
1784
1785 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1786 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1787 </dd>
1788
1789 <dt><b>Integer constants</b></dt>
1790
1791 <dd>Standard integers (such as '4') are constants of the <a
1792 href="#t_integer">integer</a> type. Negative numbers may be used with
1793 integer types.
1794 </dd>
1795
1796 <dt><b>Floating point constants</b></dt>
1797
1798 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1799 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1800 notation (see below). The assembler requires the exact decimal value of
1801 a floating-point constant. For example, the assembler accepts 1.25 but
1802 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1803 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1804
1805 <dt><b>Null pointer constants</b></dt>
1806
1807 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1808 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1809
1810</dl>
1811
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1812<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1813of floating point constants. For example, the form '<tt>double
18140x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
18154.5e+15</tt>'. The only time hexadecimal floating point constants are required
1816(and the only time that they are generated by the disassembler) is when a
1817floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1818decimal floating point number in a reasonable number of digits. For example,
1819NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1820special values are represented in their IEEE hexadecimal format so that
1821assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1822<p>When using the hexadecimal form, constants of types float and double are
1823represented using the 16-digit form shown above (which matches the IEEE754
1824representation for double); float values must, however, be exactly representable
1825as IEE754 single precision.
1826Hexadecimal format is always used for long
1827double, and there are three forms of long double. The 80-bit
1828format used by x86 is represented as <tt>0xK</tt>
1829followed by 20 hexadecimal digits.
1830The 128-bit format used by PowerPC (two adjacent doubles) is represented
1831by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1832format is represented
1833by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1834target uses this format. Long doubles will only work if they match
1835the long double format on your target. All hexadecimal formats are big-endian
1836(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1837</div>
1838
1839<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1840<div class="doc_subsection">
1841<a name="aggregateconstants"> <!-- old anchor -->
1842<a name="complexconstants">Complex Constants</a></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1843</div>
1844
1845<div class="doc_text">
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1846<p>Complex constants are a (potentially recursive) combination of simple
1847constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1848
1849<dl>
1850 <dt><b>Structure constants</b></dt>
1851
1852 <dd>Structure constants are represented with notation similar to structure
1853 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1854 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1855 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]1856 must have <a href="#t_struct">structure type</a>, and the number and
1857 types of elements must match those specified by the type.
1858 </dd>
1859
1860 <dt><b>Array constants</b></dt>
1861
1862 <dd>Array constants are represented with notation similar to array type
1863 definitions (a comma separated list of elements, surrounded by square brackets
1864 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1865 constants must have <a href="#t_array">array type</a>, and the number and
1866 types of elements must match those specified by the type.
1867 </dd>
1868
1869 <dt><b>Vector constants</b></dt>
1870
1871 <dd>Vector constants are represented with notation similar to vector type
1872 definitions (a comma separated list of elements, surrounded by
1873 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1874 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1875 href="#t_vector">vector type</a>, and the number and types of elements must
1876 match those specified by the type.
1877 </dd>
1878
1879 <dt><b>Zero initialization</b></dt>
1880
1881 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1882 value to zero of <em>any</em> type, including scalar and aggregate types.
1883 This is often used to avoid having to print large zero initializers (e.g. for
1884 large arrays) and is always exactly equivalent to using explicit zero
1885 initializers.
1886 </dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1887
1888 <dt><b>Metadata node</b></dt>
1889
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1890 <dd>A metadata node is a structure-like constant with
1891 <a href="#t_metadata">metadata type</a>. For example:
1892 "<tt>metadata !{ i32 0, metadata !"test" }</tt>". Unlike other constants
1893 that are meant to be interpreted as part of the instruction stream, metadata
1894 is a place to attach additional information such as debug info.
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1895 </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1896</dl>
1897
1898</div>
1899
1900<!-- ======================================================================= -->
1901<div class="doc_subsection">
1902 <a name="globalconstants">Global Variable and Function Addresses</a>
1903</div>
1904
1905<div class="doc_text">
1906
1907<p>The addresses of <a href="#globalvars">global variables</a> and <a
1908href="#functionstructure">functions</a> are always implicitly valid (link-time)
1909constants. These constants are explicitly referenced when the <a
1910href="#identifiers">identifier for the global</a> is used and always have <a
1911href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1912file:</p>
1913
1914<div class="doc_code">
1915<pre>
1916@X = global i32 17
1917@Y = global i32 42
1918@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1919</pre>
1920</div>
1921
1922</div>
1923
1924<!-- ======================================================================= -->
1925<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1926<div class="doc_text">
1927 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1928 no specific value. Undefined values may be of any type and be used anywhere
1929 a constant is permitted.</p>
1930
1931 <p>Undefined values indicate to the compiler that the program is well defined
1932 no matter what value is used, giving the compiler more freedom to optimize.
1933 </p>
1934</div>
1935
1936<!-- ======================================================================= -->
1937<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1938</div>
1939
1940<div class="doc_text">
1941
1942<p>Constant expressions are used to allow expressions involving other constants
1943to be used as constants. Constant expressions may be of any <a
1944href="#t_firstclass">first class</a> type and may involve any LLVM operation
1945that does not have side effects (e.g. load and call are not supported). The
1946following is the syntax for constant expressions:</p>
1947
1948<dl>
1949 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1950 <dd>Truncate a constant to another type. The bit size of CST must be larger
1951 than the bit size of TYPE. Both types must be integers.</dd>
1952
1953 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1954 <dd>Zero extend a constant to another type. The bit size of CST must be
1955 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1956
1957 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1958 <dd>Sign extend a constant to another type. The bit size of CST must be
1959 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1960
1961 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1962 <dd>Truncate a floating point constant to another floating point type. The
1963 size of CST must be larger than the size of TYPE. Both types must be
1964 floating point.</dd>
1965
1966 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1967 <dd>Floating point extend a constant to another type. The size of CST must be
1968 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1969
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1970 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1971 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1972 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1973 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1974 of the same number of elements. If the value won't fit in the integer type,
1975 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1976
1977 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1978 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1979 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1980 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1981 of the same number of elements. If the value won't fit in the integer type,
1982 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983
1984 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1985 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1986 constant. TYPE must be a scalar or vector floating point type. CST must be of
1987 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1988 of the same number of elements. If the value won't fit in the floating point
1989 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1990
1991 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1992 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1993 constant. TYPE must be a scalar or vector floating point type. CST must be of
1994 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1995 of the same number of elements. If the value won't fit in the floating point
1996 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1997
1998 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1999 <dd>Convert a pointer typed constant to the corresponding integer constant
2000 TYPE must be an integer type. CST must be of pointer type. The CST value is
2001 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
2002
2003 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
2004 <dd>Convert a integer constant to a pointer constant. TYPE must be a
2005 pointer type. CST must be of integer type. The CST value is zero extended,
2006 truncated, or unchanged to make it fit in a pointer size. This one is
2007 <i>really</i> dangerous!</dd>
2008
2009 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2010 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2011 are the same as those for the <a href="#i_bitcast">bitcast
2012 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2013
2014 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
2015
2016 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
2017 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2018 instruction, the index list may have zero or more indexes, which are required
2019 to make sense for the type of "CSTPTR".</dd>
2020
2021 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
2022
2023 <dd>Perform the <a href="#i_select">select operation</a> on
2024 constants.</dd>
2025
2026 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2027 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2028
2029 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2030 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2031
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]2032 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
2033 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
2034
2035 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
2036 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
2037
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2038 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2039
2040 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2041 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2042
2043 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2044
2045 <dd>Perform the <a href="#i_insertelement">insertelement
2046 operation</a> on constants.</dd>
2047
2048
2049 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2050
2051 <dd>Perform the <a href="#i_shufflevector">shufflevector
2052 operation</a> on constants.</dd>
2053
2054 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2055
2056 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2057 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2058 binary</a> operations. The constraints on operands are the same as those for
2059 the corresponding instruction (e.g. no bitwise operations on floating point
2060 values are allowed).</dd>
2061</dl>
2062</div>
2063
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2064<!-- ======================================================================= -->
2065<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2066</div>
2067
2068<div class="doc_text">
2069
2070<p>Embedded metadata provides a way to attach arbitrary data to the
2071instruction stream without affecting the behaviour of the program. There are
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2072two metadata primitives, strings and nodes. All metadata has the
2073<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2074point ('<tt>!</tt>').
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2075</p>
2076
2077<p>A metadata string is a string surrounded by double quotes. It can contain
2078any character by escaping non-printable characters with "\xx" where "xx" is
2079the two digit hex code. For example: "<tt>!"test\00"</tt>".
2080</p>
2081
2082<p>Metadata nodes are represented with notation similar to structure constants
2083(a comma separated list of elements, surrounded by braces and preceeded by an
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2084exclamation point). For example: "<tt>!{ metadata !"test\00", i32 10}</tt>".
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2085</p>
2086
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2087<p>A metadata node will attempt to track changes to the values it holds. In
2088the event that a value is deleted, it will be replaced with a typeless
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2089"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2090
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2091<p>Optimizations may rely on metadata to provide additional information about
2092the program that isn't available in the instructions, or that isn't easily
2093computable. Similarly, the code generator may expect a certain metadata format
2094to be used to express debugging information.</p>
2095</div>
2096
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2097<!-- *********************************************************************** -->
2098<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2099<!-- *********************************************************************** -->
2100
2101<!-- ======================================================================= -->
2102<div class="doc_subsection">
2103<a name="inlineasm">Inline Assembler Expressions</a>
2104</div>
2105
2106<div class="doc_text">
2107
2108<p>
2109LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2110Module-Level Inline Assembly</a>) through the use of a special value. This
2111value represents the inline assembler as a string (containing the instructions
2112to emit), a list of operand constraints (stored as a string), and a flag that
2113indicates whether or not the inline asm expression has side effects. An example
2114inline assembler expression is:
2115</p>
2116
2117<div class="doc_code">
2118<pre>
2119i32 (i32) asm "bswap $0", "=r,r"
2120</pre>
2121</div>
2122
2123<p>
2124Inline assembler expressions may <b>only</b> be used as the callee operand of
2125a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2126</p>
2127
2128<div class="doc_code">
2129<pre>
2130%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2131</pre>
2132</div>
2133
2134<p>
2135Inline asms with side effects not visible in the constraint list must be marked
2136as having side effects. This is done through the use of the
2137'<tt>sideeffect</tt>' keyword, like so:
2138</p>
2139
2140<div class="doc_code">
2141<pre>
2142call void asm sideeffect "eieio", ""()
2143</pre>
2144</div>
2145
2146<p>TODO: The format of the asm and constraints string still need to be
2147documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2148need to be documented). This is probably best done by reference to another
2149document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2150</p>
2151
2152</div>
2153
2154<!-- *********************************************************************** -->
2155<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2156<!-- *********************************************************************** -->
2157
2158<div class="doc_text">
2159
2160<p>The LLVM instruction set consists of several different
2161classifications of instructions: <a href="#terminators">terminator
2162instructions</a>, <a href="#binaryops">binary instructions</a>,
2163<a href="#bitwiseops">bitwise binary instructions</a>, <a
2164 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2165instructions</a>.</p>
2166
2167</div>
2168
2169<!-- ======================================================================= -->
2170<div class="doc_subsection"> <a name="terminators">Terminator
2171Instructions</a> </div>
2172
2173<div class="doc_text">
2174
2175<p>As mentioned <a href="#functionstructure">previously</a>, every
2176basic block in a program ends with a "Terminator" instruction, which
2177indicates which block should be executed after the current block is
2178finished. These terminator instructions typically yield a '<tt>void</tt>'
2179value: they produce control flow, not values (the one exception being
2180the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2181<p>There are six different terminator instructions: the '<a
2182 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2183instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2184the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2185 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2186 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2187
2188</div>
2189
2190<!-- _______________________________________________________________________ -->
2191<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2192Instruction</a> </div>
2193<div class="doc_text">
2194<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2195<pre>
2196 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]2197 ret void <i>; Return from void function</i>
2198</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2200<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2201
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2202<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2203optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2204<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2205returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2206control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2207
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2208<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2209
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2210<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2211the return value. The type of the return value must be a
2212'<a href="#t_firstclass">first class</a>' type.</p>
2213
2214<p>A function is not <a href="#wellformed">well formed</a> if
2215it it has a non-void return type and contains a '<tt>ret</tt>'
2216instruction with no return value or a return value with a type that
2217does not match its type, or if it has a void return type and contains
2218a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2220<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2221
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2222<p>When the '<tt>ret</tt>' instruction is executed, control flow
2223returns back to the calling function's context. If the caller is a "<a
2224 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2225the instruction after the call. If the caller was an "<a
2226 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2227at the beginning of the "normal" destination block. If the instruction
2228returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2229return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2230
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2231<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2232
2233<pre>
2234 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2235 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2236 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2237</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2238
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2239<p>Note that the code generator does not yet fully support large
2240 return values. The specific sizes that are currently supported are
2241 dependent on the target. For integers, on 32-bit targets the limit
2242 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2243 For aggregate types, the current limits are dependent on the element
2244 types; for example targets are often limited to 2 total integer
2245 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2247</div>
2248<!-- _______________________________________________________________________ -->
2249<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2250<div class="doc_text">
2251<h5>Syntax:</h5>
2252<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2253</pre>
2254<h5>Overview:</h5>
2255<p>The '<tt>br</tt>' instruction is used to cause control flow to
2256transfer to a different basic block in the current function. There are
2257two forms of this instruction, corresponding to a conditional branch
2258and an unconditional branch.</p>
2259<h5>Arguments:</h5>
2260<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2261single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2262unconditional form of the '<tt>br</tt>' instruction takes a single
2263'<tt>label</tt>' value as a target.</p>
2264<h5>Semantics:</h5>
2265<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2266argument is evaluated. If the value is <tt>true</tt>, control flows
2267to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2268control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2269<h5>Example:</h5>
Chris Lattner95127832009-05-09 18:11:50 +0000[diff] [blame]2270<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2271 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2272</div>
2273<!-- _______________________________________________________________________ -->
2274<div class="doc_subsubsection">
2275 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2276</div>
2277
2278<div class="doc_text">
2279<h5>Syntax:</h5>
2280
2281<pre>
2282 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2283</pre>
2284
2285<h5>Overview:</h5>
2286
2287<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2288several different places. It is a generalization of the '<tt>br</tt>'
2289instruction, allowing a branch to occur to one of many possible
2290destinations.</p>
2291
2292
2293<h5>Arguments:</h5>
2294
2295<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2296comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2297an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2298table is not allowed to contain duplicate constant entries.</p>
2299
2300<h5>Semantics:</h5>
2301
2302<p>The <tt>switch</tt> instruction specifies a table of values and
2303destinations. When the '<tt>switch</tt>' instruction is executed, this
2304table is searched for the given value. If the value is found, control flow is
2305transfered to the corresponding destination; otherwise, control flow is
2306transfered to the default destination.</p>
2307
2308<h5>Implementation:</h5>
2309
2310<p>Depending on properties of the target machine and the particular
2311<tt>switch</tt> instruction, this instruction may be code generated in different
2312ways. For example, it could be generated as a series of chained conditional
2313branches or with a lookup table.</p>
2314
2315<h5>Example:</h5>
2316
2317<pre>
2318 <i>; Emulate a conditional br instruction</i>
2319 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2320 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321
2322 <i>; Emulate an unconditional br instruction</i>
2323 switch i32 0, label %dest [ ]
2324
2325 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2326 switch i32 %val, label %otherwise [ i32 0, label %onzero
2327 i32 1, label %onone
2328 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2329</pre>
2330</div>
2331
2332<!-- _______________________________________________________________________ -->
2333<div class="doc_subsubsection">
2334 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2335</div>
2336
2337<div class="doc_text">
2338
2339<h5>Syntax:</h5>
2340
2341<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2342 &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]2343 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2344</pre>
2345
2346<h5>Overview:</h5>
2347
2348<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2349function, with the possibility of control flow transfer to either the
2350'<tt>normal</tt>' label or the
2351'<tt>exception</tt>' label. If the callee function returns with the
2352"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2353"normal" label. If the callee (or any indirect callees) returns with the "<a
2354href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2355continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2356
2357<h5>Arguments:</h5>
2358
2359<p>This instruction requires several arguments:</p>
2360
2361<ol>
2362 <li>
2363 The optional "cconv" marker indicates which <a href="#callingconv">calling
2364 convention</a> the call should use. If none is specified, the call defaults
2365 to using C calling conventions.
2366 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2367
2368 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2369 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2370 and '<tt>inreg</tt>' attributes are valid here.</li>
2371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2372 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2373 function value being invoked. In most cases, this is a direct function
2374 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2375 an arbitrary pointer to function value.
2376 </li>
2377
2378 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2379 function to be invoked. </li>
2380
2381 <li>'<tt>function args</tt>': argument list whose types match the function
2382 signature argument types. If the function signature indicates the function
2383 accepts a variable number of arguments, the extra arguments can be
2384 specified. </li>
2385
2386 <li>'<tt>normal label</tt>': the label reached when the called function
2387 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2388
2389 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2390 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2391
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2392 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2393 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2394 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2395</ol>
2396
2397<h5>Semantics:</h5>
2398
2399<p>This instruction is designed to operate as a standard '<tt><a
2400href="#i_call">call</a></tt>' instruction in most regards. The primary
2401difference is that it establishes an association with a label, which is used by
2402the runtime library to unwind the stack.</p>
2403
2404<p>This instruction is used in languages with destructors to ensure that proper
2405cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2406exception. Additionally, this is important for implementation of
2407'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2408
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]2409<p>For the purposes of the SSA form, the definition of the value
2410returned by the '<tt>invoke</tt>' instruction is deemed to occur on
2411the edge from the current block to the "normal" label. If the callee
2412unwinds then no return value is available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2413
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2414<h5>Example:</h5>
2415<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2416 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2417 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2418 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2419 unwind label %TestCleanup <i>; {i32}:retval set</i>
2420</pre>
2421</div>
2422
2423
2424<!-- _______________________________________________________________________ -->
2425
2426<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2427Instruction</a> </div>
2428
2429<div class="doc_text">
2430
2431<h5>Syntax:</h5>
2432<pre>
2433 unwind
2434</pre>
2435
2436<h5>Overview:</h5>
2437
2438<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2439at the first callee in the dynamic call stack which used an <a
2440href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2441primarily used to implement exception handling.</p>
2442
2443<h5>Semantics:</h5>
2444
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2445<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2446immediately halt. The dynamic call stack is then searched for the first <a
2447href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2448execution continues at the "exceptional" destination block specified by the
2449<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2450dynamic call chain, undefined behavior results.</p>
2451</div>
2452
2453<!-- _______________________________________________________________________ -->
2454
2455<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2456Instruction</a> </div>
2457
2458<div class="doc_text">
2459
2460<h5>Syntax:</h5>
2461<pre>
2462 unreachable
2463</pre>
2464
2465<h5>Overview:</h5>
2466
2467<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2468instruction is used to inform the optimizer that a particular portion of the
2469code is not reachable. This can be used to indicate that the code after a
2470no-return function cannot be reached, and other facts.</p>
2471
2472<h5>Semantics:</h5>
2473
2474<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2475</div>
2476
2477
2478
2479<!-- ======================================================================= -->
2480<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2481<div class="doc_text">
2482<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2483program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2484produce a single value. The operands might represent
2485multiple 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]2486The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2487<p>There are several different binary operators:</p>
2488</div>
2489<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2490<div class="doc_subsubsection">
2491 <a name="i_add">'<tt>add</tt>' Instruction</a>
2492</div>
2493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2497
2498<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2499 &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]2500</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2502<h5>Overview:</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 '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2505
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2507
2508<p>The two arguments to the '<tt>add</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2509 href="#t_integer">integer</a> or
2510 <a href="#t_vector">vector</a> of integer values. Both arguments must
2511 have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2513<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2514
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2515<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2516
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2517<p>If the sum has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2518mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2519the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2520
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2521<p>Because LLVM integers use a two's complement representation, this
2522instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2523
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2524<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2525
2526<pre>
2527 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2528</pre>
2529</div>
2530<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2531<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2532 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2533</div>
2534
2535<div class="doc_text">
2536
2537<h5>Syntax:</h5>
2538
2539<pre>
2540 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2541</pre>
2542
2543<h5>Overview:</h5>
2544
2545<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2546
2547<h5>Arguments:</h5>
2548
2549<p>The two arguments to the '<tt>fadd</tt>' instruction must be
2550<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2551floating point values. Both arguments must have identical types.</p>
2552
2553<h5>Semantics:</h5>
2554
2555<p>The value produced is the floating point sum of the two operands.</p>
2556
2557<h5>Example:</h5>
2558
2559<pre>
2560 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2561</pre>
2562</div>
2563<!-- _______________________________________________________________________ -->
2564<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2565 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2566</div>
2567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2568<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2569
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2570<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2571
2572<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2573 &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]2574</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2575
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2576<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578<p>The '<tt>sub</tt>' instruction returns the difference of its two
2579operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2580
2581<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2582'<tt>neg</tt>' instruction present in most other intermediate
2583representations.</p>
2584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2585<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2586
2587<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2588 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2589 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2592
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2593<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2594
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2595<p>If the difference has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2596mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2597the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2598
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2599<p>Because LLVM integers use a two's complement representation, this
2600instruction is appropriate for both signed and unsigned integers.</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>
2603<pre>
2604 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2605 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
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<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2610<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2611 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2612</div>
2613
2614<div class="doc_text">
2615
2616<h5>Syntax:</h5>
2617
2618<pre>
2619 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2620</pre>
2621
2622<h5>Overview:</h5>
2623
2624<p>The '<tt>fsub</tt>' instruction returns the difference of its two
2625operands.</p>
2626
2627<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
2628'<tt>fneg</tt>' instruction present in most other intermediate
2629representations.</p>
2630
2631<h5>Arguments:</h5>
2632
2633<p>The two arguments to the '<tt>fsub</tt>' instruction must be <a
2634 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2635 of floating point values. Both arguments must have identical types.</p>
2636
2637<h5>Semantics:</h5>
2638
2639<p>The value produced is the floating point difference of the two operands.</p>
2640
2641<h5>Example:</h5>
2642<pre>
2643 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2644 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2645</pre>
2646</div>
2647
2648<!-- _______________________________________________________________________ -->
2649<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2650 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2651</div>
2652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2654
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2655<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2656<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]2657</pre>
2658<h5>Overview:</h5>
2659<p>The '<tt>mul</tt>' instruction returns the product of its two
2660operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2663
2664<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2665href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2666values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2669
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2670<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2671
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2672<p>If the result of the multiplication has unsigned overflow,
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2673the result returned is the mathematical result modulo
26742<sup>n</sup>, where n is the bit width of the result.</p>
2675<p>Because LLVM integers use a two's complement representation, and the
2676result is the same width as the operands, this instruction returns the
2677correct result for both signed and unsigned integers. If a full product
2678(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2679should be sign-extended or zero-extended as appropriate to the
2680width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2681<h5>Example:</h5>
2682<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2683</pre>
2684</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2686<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2687<div class="doc_subsubsection">
2688 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2689</div>
2690
2691<div class="doc_text">
2692
2693<h5>Syntax:</h5>
2694<pre> &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2695</pre>
2696<h5>Overview:</h5>
2697<p>The '<tt>fmul</tt>' instruction returns the product of its two
2698operands.</p>
2699
2700<h5>Arguments:</h5>
2701
2702<p>The two arguments to the '<tt>fmul</tt>' instruction must be
2703<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2704of floating point values. Both arguments must have identical types.</p>
2705
2706<h5>Semantics:</h5>
2707
2708<p>The value produced is the floating point product of the two operands.</p>
2709
2710<h5>Example:</h5>
2711<pre> &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
2712</pre>
2713</div>
2714
2715<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2716<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2717</a></div>
2718<div class="doc_text">
2719<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2720<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]2721</pre>
2722<h5>Overview:</h5>
2723<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2724operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2725
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2726<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2727
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2728<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2729<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2730values. Both arguments must have identical types.</p>
2731
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2733
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2734<p>The value produced is the unsigned integer quotient of the two operands.</p>
2735<p>Note that unsigned integer division and signed integer division are distinct
2736operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2737<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<h5>Example:</h5>
2739<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2740</pre>
2741</div>
2742<!-- _______________________________________________________________________ -->
2743<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2744</a> </div>
2745<div class="doc_text">
2746<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2747<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2748 &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]2749</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2751<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2752
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2753<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2754operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2755
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2756<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2757
2758<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2759<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2760values. Both arguments must have identical types.</p>
2761
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2762<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2763<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]2764<p>Note that signed integer division and unsigned integer division are distinct
2765operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2766<p>Division by zero leads to undefined behavior. Overflow also leads to
2767undefined behavior; this is a rare case, but can occur, for example,
2768by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2769<h5>Example:</h5>
2770<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2771</pre>
2772</div>
2773<!-- _______________________________________________________________________ -->
2774<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2775Instruction</a> </div>
2776<div class="doc_text">
2777<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2778<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2779 &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]2780</pre>
2781<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2783<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2784operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2785
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2786<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2788<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2789<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2790of floating point values. Both arguments must have identical types.</p>
2791
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2792<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2793
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2794<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2795
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2796<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2797
2798<pre>
2799 &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]2800</pre>
2801</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2803<!-- _______________________________________________________________________ -->
2804<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2805</div>
2806<div class="doc_text">
2807<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2808<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]2809</pre>
2810<h5>Overview:</h5>
2811<p>The '<tt>urem</tt>' instruction returns the remainder from the
2812unsigned division of its two arguments.</p>
2813<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2814<p>The two arguments to the '<tt>urem</tt>' instruction must be
2815<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2816values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2817<h5>Semantics:</h5>
2818<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2819This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2820<p>Note that unsigned integer remainder and signed integer remainder are
2821distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2822<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2823<h5>Example:</h5>
2824<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2825</pre>
2826
2827</div>
2828<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2829<div class="doc_subsubsection">
2830 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2831</div>
2832
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2833<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2834
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2835<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2836
2837<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2838 &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]2839</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2840
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2841<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2842
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2843<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2844signed division of its two operands. This instruction can also take
2845<a href="#t_vector">vector</a> versions of the values in which case
2846the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2848<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2849
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2850<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2851<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2852values. Both arguments must have identical types.</p>
2853
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2854<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2855
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2856<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2857has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2858operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2859a value. For more information about the difference, see <a
2860 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2861Math Forum</a>. For a table of how this is implemented in various languages,
2862please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2863Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2864<p>Note that signed integer remainder and unsigned integer remainder are
2865distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2866<p>Taking the remainder of a division by zero leads to undefined behavior.
2867Overflow also leads to undefined behavior; this is a rare case, but can occur,
2868for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2869(The remainder doesn't actually overflow, but this rule lets srem be
2870implemented using instructions that return both the result of the division
2871and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2872<h5>Example:</h5>
2873<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2874</pre>
2875
2876</div>
2877<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2878<div class="doc_subsubsection">
2879 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2880
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2881<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2882
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2883<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2884<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]2885</pre>
2886<h5>Overview:</h5>
2887<p>The '<tt>frem</tt>' instruction returns the remainder from the
2888division of its two operands.</p>
2889<h5>Arguments:</h5>
2890<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2891<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2892of floating point values. Both arguments must have identical types.</p>
2893
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2894<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2895
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2896<p>This instruction returns the <i>remainder</i> of a division.
2897The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2898
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2899<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2900
2901<pre>
2902 &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]2903</pre>
2904</div>
2905
2906<!-- ======================================================================= -->
2907<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2908Operations</a> </div>
2909<div class="doc_text">
2910<p>Bitwise binary operators are used to do various forms of
2911bit-twiddling in a program. They are generally very efficient
2912instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2913instructions. They require two operands of the same type, execute an operation on them,
2914and 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]2915</div>
2916
2917<!-- _______________________________________________________________________ -->
2918<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2919Instruction</a> </div>
2920<div class="doc_text">
2921<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2922<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]2923</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2924
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2925<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2926
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2927<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2928the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2929
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2930<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2931
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2932<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2933 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2934type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2935
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2936<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2937
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2938<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2939where 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]2940equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2941If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2942corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2944<h5>Example:</h5><pre>
2945 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2946 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2947 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2948 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2949 &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]2950</pre>
2951</div>
2952<!-- _______________________________________________________________________ -->
2953<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2954Instruction</a> </div>
2955<div class="doc_text">
2956<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2957<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]2958</pre>
2959
2960<h5>Overview:</h5>
2961<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2962operand shifted to the right a specified number of bits with zero fill.</p>
2963
2964<h5>Arguments:</h5>
2965<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2966<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]2967type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2968
2969<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2971<p>This instruction always performs a logical shift right operation. The most
2972significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2973shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2974the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2975vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2976amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2977
2978<h5>Example:</h5>
2979<pre>
2980 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2981 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2982 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2983 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2984 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2985 &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]2986</pre>
2987</div>
2988
2989<!-- _______________________________________________________________________ -->
2990<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2991Instruction</a> </div>
2992<div class="doc_text">
2993
2994<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2995<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]2996</pre>
2997
2998<h5>Overview:</h5>
2999<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3000operand shifted to the right a specified number of bits with sign extension.</p>
3001
3002<h5>Arguments:</h5>
3003<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]3004<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]3005type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3006
3007<h5>Semantics:</h5>
3008<p>This instruction always performs an arithmetic shift right operation,
3009The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3010of <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]3011larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
3012arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
3013corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3014
3015<h5>Example:</h5>
3016<pre>
3017 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3018 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3019 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3020 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3021 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3022 &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]3023</pre>
3024</div>
3025
3026<!-- _______________________________________________________________________ -->
3027<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3028Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3029
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3030<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3031
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3032<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3033
3034<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3035 &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]3036</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3037
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3038<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3039
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3040<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
3041its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3042
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3043<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3044
3045<p>The two arguments to the '<tt>and</tt>' instruction must be
3046<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3047values. Both arguments must have identical types.</p>
3048
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3049<h5>Semantics:</h5>
3050<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
3051<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3052<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3053<table border="1" cellspacing="0" cellpadding="4">
3054 <tbody>
3055 <tr>
3056 <td>In0</td>
3057 <td>In1</td>
3058 <td>Out</td>
3059 </tr>
3060 <tr>
3061 <td>0</td>
3062 <td>0</td>
3063 <td>0</td>
3064 </tr>
3065 <tr>
3066 <td>0</td>
3067 <td>1</td>
3068 <td>0</td>
3069 </tr>
3070 <tr>
3071 <td>1</td>
3072 <td>0</td>
3073 <td>0</td>
3074 </tr>
3075 <tr>
3076 <td>1</td>
3077 <td>1</td>
3078 <td>1</td>
3079 </tr>
3080 </tbody>
3081</table>
3082</div>
3083<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3084<pre>
3085 &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]3086 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3087 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3088</pre>
3089</div>
3090<!-- _______________________________________________________________________ -->
3091<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
3092<div class="doc_text">
3093<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3094<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]3095</pre>
3096<h5>Overview:</h5>
3097<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
3098or of its two operands.</p>
3099<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3100
3101<p>The two arguments to the '<tt>or</tt>' instruction must be
3102<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3103values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3104<h5>Semantics:</h5>
3105<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
3106<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3107<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3108<table border="1" cellspacing="0" cellpadding="4">
3109 <tbody>
3110 <tr>
3111 <td>In0</td>
3112 <td>In1</td>
3113 <td>Out</td>
3114 </tr>
3115 <tr>
3116 <td>0</td>
3117 <td>0</td>
3118 <td>0</td>
3119 </tr>
3120 <tr>
3121 <td>0</td>
3122 <td>1</td>
3123 <td>1</td>
3124 </tr>
3125 <tr>
3126 <td>1</td>
3127 <td>0</td>
3128 <td>1</td>
3129 </tr>
3130 <tr>
3131 <td>1</td>
3132 <td>1</td>
3133 <td>1</td>
3134 </tr>
3135 </tbody>
3136</table>
3137</div>
3138<h5>Example:</h5>
3139<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3140 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3141 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3142</pre>
3143</div>
3144<!-- _______________________________________________________________________ -->
3145<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3146Instruction</a> </div>
3147<div class="doc_text">
3148<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3149<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]3150</pre>
3151<h5>Overview:</h5>
3152<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3153or of its two operands. The <tt>xor</tt> is used to implement the
3154"one's complement" operation, which is the "~" operator in C.</p>
3155<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3156<p>The two arguments to the '<tt>xor</tt>' instruction must be
3157<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3158values. Both arguments must have identical types.</p>
3159
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3160<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3162<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3163<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3164<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3165<table border="1" cellspacing="0" cellpadding="4">
3166 <tbody>
3167 <tr>
3168 <td>In0</td>
3169 <td>In1</td>
3170 <td>Out</td>
3171 </tr>
3172 <tr>
3173 <td>0</td>
3174 <td>0</td>
3175 <td>0</td>
3176 </tr>
3177 <tr>
3178 <td>0</td>
3179 <td>1</td>
3180 <td>1</td>
3181 </tr>
3182 <tr>
3183 <td>1</td>
3184 <td>0</td>
3185 <td>1</td>
3186 </tr>
3187 <tr>
3188 <td>1</td>
3189 <td>1</td>
3190 <td>0</td>
3191 </tr>
3192 </tbody>
3193</table>
3194</div>
3195<p> </p>
3196<h5>Example:</h5>
3197<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3198 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3199 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3200 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3201</pre>
3202</div>
3203
3204<!-- ======================================================================= -->
3205<div class="doc_subsection">
3206 <a name="vectorops">Vector Operations</a>
3207</div>
3208
3209<div class="doc_text">
3210
3211<p>LLVM supports several instructions to represent vector operations in a
3212target-independent manner. These instructions cover the element-access and
3213vector-specific operations needed to process vectors effectively. While LLVM
3214does directly support these vector operations, many sophisticated algorithms
3215will want to use target-specific intrinsics to take full advantage of a specific
3216target.</p>
3217
3218</div>
3219
3220<!-- _______________________________________________________________________ -->
3221<div class="doc_subsubsection">
3222 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3223</div>
3224
3225<div class="doc_text">
3226
3227<h5>Syntax:</h5>
3228
3229<pre>
3230 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3231</pre>
3232
3233<h5>Overview:</h5>
3234
3235<p>
3236The '<tt>extractelement</tt>' instruction extracts a single scalar
3237element from a vector at a specified index.
3238</p>
3239
3240
3241<h5>Arguments:</h5>
3242
3243<p>
3244The first operand of an '<tt>extractelement</tt>' instruction is a
3245value of <a href="#t_vector">vector</a> type. The second operand is
3246an index indicating the position from which to extract the element.
3247The index may be a variable.</p>
3248
3249<h5>Semantics:</h5>
3250
3251<p>
3252The result is a scalar of the same type as the element type of
3253<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3254<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3255results are undefined.
3256</p>
3257
3258<h5>Example:</h5>
3259
3260<pre>
3261 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3262</pre>
3263</div>
3264
3265
3266<!-- _______________________________________________________________________ -->
3267<div class="doc_subsubsection">
3268 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3269</div>
3270
3271<div class="doc_text">
3272
3273<h5>Syntax:</h5>
3274
3275<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3276 &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]3277</pre>
3278
3279<h5>Overview:</h5>
3280
3281<p>
3282The '<tt>insertelement</tt>' instruction inserts a scalar
3283element into a vector at a specified index.
3284</p>
3285
3286
3287<h5>Arguments:</h5>
3288
3289<p>
3290The first operand of an '<tt>insertelement</tt>' instruction is a
3291value of <a href="#t_vector">vector</a> type. The second operand is a
3292scalar value whose type must equal the element type of the first
3293operand. The third operand is an index indicating the position at
3294which to insert the value. The index may be a variable.</p>
3295
3296<h5>Semantics:</h5>
3297
3298<p>
3299The result is a vector of the same type as <tt>val</tt>. Its
3300element values are those of <tt>val</tt> except at position
3301<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3302exceeds the length of <tt>val</tt>, the results are undefined.
3303</p>
3304
3305<h5>Example:</h5>
3306
3307<pre>
3308 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3309</pre>
3310</div>
3311
3312<!-- _______________________________________________________________________ -->
3313<div class="doc_subsubsection">
3314 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3315</div>
3316
3317<div class="doc_text">
3318
3319<h5>Syntax:</h5>
3320
3321<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3322 &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]3323</pre>
3324
3325<h5>Overview:</h5>
3326
3327<p>
3328The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3329from two input vectors, returning a vector with the same element type as
3330the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3331</p>
3332
3333<h5>Arguments:</h5>
3334
3335<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3336The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3337with types that match each other. The third argument is a shuffle mask whose
3338element type is always 'i32'. The result of the instruction is a vector whose
3339length is the same as the shuffle mask and whose element type is the same as
3340the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341</p>
3342
3343<p>
3344The shuffle mask operand is required to be a constant vector with either
3345constant integer or undef values.
3346</p>
3347
3348<h5>Semantics:</h5>
3349
3350<p>
3351The elements of the two input vectors are numbered from left to right across
3352both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3353the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3354gets. The element selector may be undef (meaning "don't care") and the second
3355operand may be undef if performing a shuffle from only one vector.
3356</p>
3357
3358<h5>Example:</h5>
3359
3360<pre>
3361 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3362 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3363 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3364 &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]3365 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3366 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3367 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3368 &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]3369</pre>
3370</div>
3371
3372
3373<!-- ======================================================================= -->
3374<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3375 <a name="aggregateops">Aggregate Operations</a>
3376</div>
3377
3378<div class="doc_text">
3379
3380<p>LLVM supports several instructions for working with aggregate values.
3381</p>
3382
3383</div>
3384
3385<!-- _______________________________________________________________________ -->
3386<div class="doc_subsubsection">
3387 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3388</div>
3389
3390<div class="doc_text">
3391
3392<h5>Syntax:</h5>
3393
3394<pre>
3395 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3396</pre>
3397
3398<h5>Overview:</h5>
3399
3400<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3401The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3402or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3403</p>
3404
3405
3406<h5>Arguments:</h5>
3407
3408<p>
3409The first operand of an '<tt>extractvalue</tt>' instruction is a
3410value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3411type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3412in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3413'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3414</p>
3415
3416<h5>Semantics:</h5>
3417
3418<p>
3419The result is the value at the position in the aggregate specified by
3420the index operands.
3421</p>
3422
3423<h5>Example:</h5>
3424
3425<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3426 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3427</pre>
3428</div>
3429
3430
3431<!-- _______________________________________________________________________ -->
3432<div class="doc_subsubsection">
3433 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3434</div>
3435
3436<div class="doc_text">
3437
3438<h5>Syntax:</h5>
3439
3440<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3441 &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]3442</pre>
3443
3444<h5>Overview:</h5>
3445
3446<p>
3447The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3448into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3449</p>
3450
3451
3452<h5>Arguments:</h5>
3453
3454<p>
3455The first operand of an '<tt>insertvalue</tt>' instruction is a
3456value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3457The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3458The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3459indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3460indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3461'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3462The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3463by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3464</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3465
3466<h5>Semantics:</h5>
3467
3468<p>
3469The result is an aggregate of the same type as <tt>val</tt>. Its
3470value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3471specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3472</p>
3473
3474<h5>Example:</h5>
3475
3476<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3477 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3478</pre>
3479</div>
3480
3481
3482<!-- ======================================================================= -->
3483<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3484 <a name="memoryops">Memory Access and Addressing Operations</a>
3485</div>
3486
3487<div class="doc_text">
3488
3489<p>A key design point of an SSA-based representation is how it
3490represents memory. In LLVM, no memory locations are in SSA form, which
3491makes things very simple. This section describes how to read, write,
3492allocate, and free memory in LLVM.</p>
3493
3494</div>
3495
3496<!-- _______________________________________________________________________ -->
3497<div class="doc_subsubsection">
3498 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3499</div>
3500
3501<div class="doc_text">
3502
3503<h5>Syntax:</h5>
3504
3505<pre>
3506 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3507</pre>
3508
3509<h5>Overview:</h5>
3510
3511<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3512heap and returns a pointer to it. The object is always allocated in the generic
3513address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3514
3515<h5>Arguments:</h5>
3516
3517<p>The '<tt>malloc</tt>' instruction allocates
3518<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3519bytes of memory from the operating system and returns a pointer of the
3520appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3521number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3522If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3523be aligned to at least that boundary. If not specified, or if zero, the target can
3524choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3525
3526<p>'<tt>type</tt>' must be a sized type.</p>
3527
3528<h5>Semantics:</h5>
3529
3530<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3531a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3532result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3533
3534<h5>Example:</h5>
3535
3536<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3537 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3538
3539 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3540 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3541 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3542 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3543 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3544</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3545
3546<p>Note that the code generator does not yet respect the
3547 alignment value.</p>
3548
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3549</div>
3550
3551<!-- _______________________________________________________________________ -->
3552<div class="doc_subsubsection">
3553 <a name="i_free">'<tt>free</tt>' Instruction</a>
3554</div>
3555
3556<div class="doc_text">
3557
3558<h5>Syntax:</h5>
3559
3560<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3561 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3562</pre>
3563
3564<h5>Overview:</h5>
3565
3566<p>The '<tt>free</tt>' instruction returns memory back to the unused
3567memory heap to be reallocated in the future.</p>
3568
3569<h5>Arguments:</h5>
3570
3571<p>'<tt>value</tt>' shall be a pointer value that points to a value
3572that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3573instruction.</p>
3574
3575<h5>Semantics:</h5>
3576
3577<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3578after this instruction executes. If the pointer is null, the operation
3579is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3580
3581<h5>Example:</h5>
3582
3583<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3584 %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]3585 free [4 x i8]* %array
3586</pre>
3587</div>
3588
3589<!-- _______________________________________________________________________ -->
3590<div class="doc_subsubsection">
3591 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3592</div>
3593
3594<div class="doc_text">
3595
3596<h5>Syntax:</h5>
3597
3598<pre>
3599 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3600</pre>
3601
3602<h5>Overview:</h5>
3603
3604<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3605currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3606returns to its caller. The object is always allocated in the generic address
3607space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3608
3609<h5>Arguments:</h5>
3610
3611<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3612bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3613appropriate type to the program. If "NumElements" is specified, it is the
3614number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3615If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3616to be aligned to at least that boundary. If not specified, or if zero, the target
3617can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3618
3619<p>'<tt>type</tt>' may be any sized type.</p>
3620
3621<h5>Semantics:</h5>
3622
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3623<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3624there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3625memory is automatically released when the function returns. The '<tt>alloca</tt>'
3626instruction is commonly used to represent automatic variables that must
3627have an address available. When the function returns (either with the <tt><a
3628 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]3629instructions), the memory is reclaimed. Allocating zero bytes
3630is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3631
3632<h5>Example:</h5>
3633
3634<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3635 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3636 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3637 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3638 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3639</pre>
3640</div>
3641
3642<!-- _______________________________________________________________________ -->
3643<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3644Instruction</a> </div>
3645<div class="doc_text">
3646<h5>Syntax:</h5>
3647<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>
3648<h5>Overview:</h5>
3649<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3650<h5>Arguments:</h5>
3651<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3652address from which to load. The pointer must point to a <a
3653 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3654marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3655the number or order of execution of this <tt>load</tt> with other
3656volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3657instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3658<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3659The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3660(that is, the alignment of the memory address). A value of 0 or an
3661omitted "align" argument means that the operation has the preferential
3662alignment for the target. It is the responsibility of the code emitter
3663to ensure that the alignment information is correct. Overestimating
3664the alignment results in an undefined behavior. Underestimating the
3665alignment may produce less efficient code. An alignment of 1 is always
3666safe.
3667</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3668<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3669<p>The location of memory pointed to is loaded. If the value being loaded
3670is of scalar type then the number of bytes read does not exceed the minimum
3671number of bytes needed to hold all bits of the type. For example, loading an
3672<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3673<tt>i20</tt> with a size that is not an integral number of bytes, the result
3674is undefined if the value was not originally written using a store of the
3675same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3676<h5>Examples:</h5>
3677<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3678 <a
3679 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3680 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3681</pre>
3682</div>
3683<!-- _______________________________________________________________________ -->
3684<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3685Instruction</a> </div>
3686<div class="doc_text">
3687<h5>Syntax:</h5>
3688<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3689 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3690</pre>
3691<h5>Overview:</h5>
3692<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3693<h5>Arguments:</h5>
3694<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3695to 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]3696operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3697of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3698operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3699optimizer is not allowed to modify the number or order of execution of
3700this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3701 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3702<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3703The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3704(that is, the alignment of the memory address). A value of 0 or an
3705omitted "align" argument means that the operation has the preferential
3706alignment for the target. It is the responsibility of the code emitter
3707to ensure that the alignment information is correct. Overestimating
3708the alignment results in an undefined behavior. Underestimating the
3709alignment may produce less efficient code. An alignment of 1 is always
3710safe.
3711</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3712<h5>Semantics:</h5>
3713<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3714at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3715If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3716written does not exceed the minimum number of bytes needed to hold all
3717bits of the type. For example, storing an <tt>i24</tt> writes at most
3718three bytes. When writing a value of a type like <tt>i20</tt> with a
3719size that is not an integral number of bytes, it is unspecified what
3720happens to the extra bits that do not belong to the type, but they will
3721typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3722<h5>Example:</h5>
3723<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3724 store i32 3, i32* %ptr <i>; yields {void}</i>
3725 %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]3726</pre>
3727</div>
3728
3729<!-- _______________________________________________________________________ -->
3730<div class="doc_subsubsection">
3731 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3732</div>
3733
3734<div class="doc_text">
3735<h5>Syntax:</h5>
3736<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3737 &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]3738</pre>
3739
3740<h5>Overview:</h5>
3741
3742<p>
3743The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3744subelement of an aggregate data structure. It performs address calculation only
3745and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746
3747<h5>Arguments:</h5>
3748
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3749<p>The first argument is always a pointer, and forms the basis of the
3750calculation. The remaining arguments are indices, that indicate which of the
3751elements of the aggregate object are indexed. The interpretation of each index
3752is dependent on the type being indexed into. The first index always indexes the
3753pointer value given as the first argument, the second index indexes a value of
3754the type pointed to (not necessarily the value directly pointed to, since the
3755first index can be non-zero), etc. The first type indexed into must be a pointer
3756value, subsequent types can be arrays, vectors and structs. Note that subsequent
3757types being indexed into can never be pointers, since that would require loading
3758the pointer before continuing calculation.</p>
3759
3760<p>The type of each index argument depends on the type it is indexing into.
3761When indexing into a (packed) structure, only <tt>i32</tt> integer
3762<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3763integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3764
3765<p>For example, let's consider a C code fragment and how it gets
3766compiled to LLVM:</p>
3767
3768<div class="doc_code">
3769<pre>
3770struct RT {
3771 char A;
3772 int B[10][20];
3773 char C;
3774};
3775struct ST {
3776 int X;
3777 double Y;
3778 struct RT Z;
3779};
3780
3781int *foo(struct ST *s) {
3782 return &amp;s[1].Z.B[5][13];
3783}
3784</pre>
3785</div>
3786
3787<p>The LLVM code generated by the GCC frontend is:</p>
3788
3789<div class="doc_code">
3790<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3791%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3792%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3793
3794define i32* %foo(%ST* %s) {
3795entry:
3796 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3797 ret i32* %reg
3798}
3799</pre>
3800</div>
3801
3802<h5>Semantics:</h5>
3803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3804<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3805type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3806}</tt>' type, a structure. The second index indexes into the third element of
3807the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3808i8 }</tt>' type, another structure. The third index indexes into the second
3809element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3810array. The two dimensions of the array are subscripted into, yielding an
3811'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3812to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3813
3814<p>Note that it is perfectly legal to index partially through a
3815structure, returning a pointer to an inner element. Because of this,
3816the LLVM code for the given testcase is equivalent to:</p>
3817
3818<pre>
3819 define i32* %foo(%ST* %s) {
3820 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3821 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3822 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3823 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3824 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3825 ret i32* %t5
3826 }
3827</pre>
3828
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3829<p>Note that it is undefined to access an array out of bounds: array
3830and pointer indexes must always be within the defined bounds of the
3831array type when accessed with an instruction that dereferences the
3832pointer (e.g. a load or store instruction). The one exception for
3833this rule is zero length arrays. These arrays are defined to be
3834accessible as variable length arrays, which requires access beyond the
3835zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3836
3837<p>The getelementptr instruction is often confusing. For some more insight
3838into how it works, see <a href="GetElementPtr.html">the getelementptr
3839FAQ</a>.</p>
3840
3841<h5>Example:</h5>
3842
3843<pre>
3844 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3845 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3846 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3847 %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]3848 <i>; yields i8*:eptr</i>
3849 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3850 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3851 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3852</pre>
3853</div>
3854
3855<!-- ======================================================================= -->
3856<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3857</div>
3858<div class="doc_text">
3859<p>The instructions in this category are the conversion instructions (casting)
3860which all take a single operand and a type. They perform various bit conversions
3861on the operand.</p>
3862</div>
3863
3864<!-- _______________________________________________________________________ -->
3865<div class="doc_subsubsection">
3866 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3867</div>
3868<div class="doc_text">
3869
3870<h5>Syntax:</h5>
3871<pre>
3872 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3873</pre>
3874
3875<h5>Overview:</h5>
3876<p>
3877The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3878</p>
3879
3880<h5>Arguments:</h5>
3881<p>
3882The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3883be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3884and type of the result, which must be an <a href="#t_integer">integer</a>
3885type. The bit size of <tt>value</tt> must be larger than the bit size of
3886<tt>ty2</tt>. Equal sized types are not allowed.</p>
3887
3888<h5>Semantics:</h5>
3889<p>
3890The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3891and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3892larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3893It will always truncate bits.</p>
3894
3895<h5>Example:</h5>
3896<pre>
3897 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3898 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3899 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3900</pre>
3901</div>
3902
3903<!-- _______________________________________________________________________ -->
3904<div class="doc_subsubsection">
3905 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3906</div>
3907<div class="doc_text">
3908
3909<h5>Syntax:</h5>
3910<pre>
3911 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3912</pre>
3913
3914<h5>Overview:</h5>
3915<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3916<tt>ty2</tt>.</p>
3917
3918
3919<h5>Arguments:</h5>
3920<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3921<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3922also be of <a href="#t_integer">integer</a> type. The bit size of the
3923<tt>value</tt> must be smaller than the bit size of the destination type,
3924<tt>ty2</tt>.</p>
3925
3926<h5>Semantics:</h5>
3927<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3928bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3929
3930<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3931
3932<h5>Example:</h5>
3933<pre>
3934 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3935 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3936</pre>
3937</div>
3938
3939<!-- _______________________________________________________________________ -->
3940<div class="doc_subsubsection">
3941 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3942</div>
3943<div class="doc_text">
3944
3945<h5>Syntax:</h5>
3946<pre>
3947 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3948</pre>
3949
3950<h5>Overview:</h5>
3951<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3952
3953<h5>Arguments:</h5>
3954<p>
3955The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3956<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3957also be of <a href="#t_integer">integer</a> type. The bit size of the
3958<tt>value</tt> must be smaller than the bit size of the destination type,
3959<tt>ty2</tt>.</p>
3960
3961<h5>Semantics:</h5>
3962<p>
3963The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3964bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3965the type <tt>ty2</tt>.</p>
3966
3967<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3968
3969<h5>Example:</h5>
3970<pre>
3971 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3972 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3973</pre>
3974</div>
3975
3976<!-- _______________________________________________________________________ -->
3977<div class="doc_subsubsection">
3978 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3979</div>
3980
3981<div class="doc_text">
3982
3983<h5>Syntax:</h5>
3984
3985<pre>
3986 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3987</pre>
3988
3989<h5>Overview:</h5>
3990<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3991<tt>ty2</tt>.</p>
3992
3993
3994<h5>Arguments:</h5>
3995<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3996 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3997cast it to. The size of <tt>value</tt> must be larger than the size of
3998<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3999<i>no-op cast</i>.</p>
4000
4001<h5>Semantics:</h5>
4002<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4003<a href="#t_floating">floating point</a> type to a smaller
4004<a href="#t_floating">floating point</a> type. If the value cannot fit within
4005the destination type, <tt>ty2</tt>, then the results are undefined.</p>
4006
4007<h5>Example:</h5>
4008<pre>
4009 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4010 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4011</pre>
4012</div>
4013
4014<!-- _______________________________________________________________________ -->
4015<div class="doc_subsubsection">
4016 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4017</div>
4018<div class="doc_text">
4019
4020<h5>Syntax:</h5>
4021<pre>
4022 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4023</pre>
4024
4025<h5>Overview:</h5>
4026<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
4027floating point value.</p>
4028
4029<h5>Arguments:</h5>
4030<p>The '<tt>fpext</tt>' instruction takes a
4031<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
4032and a <a href="#t_floating">floating point</a> type to cast it to. The source
4033type must be smaller than the destination type.</p>
4034
4035<h5>Semantics:</h5>
4036<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
4037<a href="#t_floating">floating point</a> type to a larger
4038<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4039used to make a <i>no-op cast</i> because it always changes bits. Use
4040<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
4041
4042<h5>Example:</h5>
4043<pre>
4044 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4045 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4046</pre>
4047</div>
4048
4049<!-- _______________________________________________________________________ -->
4050<div class="doc_subsubsection">
4051 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4052</div>
4053<div class="doc_text">
4054
4055<h5>Syntax:</h5>
4056<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4057 &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]4058</pre>
4059
4060<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4061<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4062unsigned integer equivalent of type <tt>ty2</tt>.
4063</p>
4064
4065<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4066<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]4067scalar or vector <a href="#t_floating">floating point</a> value, and a type
4068to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4069type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4070vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4071
4072<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4073<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074<a href="#t_floating">floating point</a> operand into the nearest (rounding
4075towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
4076the results are undefined.</p>
4077
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078<h5>Example:</h5>
4079<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4080 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4081 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4082 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083</pre>
4084</div>
4085
4086<!-- _______________________________________________________________________ -->
4087<div class="doc_subsubsection">
4088 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4089</div>
4090<div class="doc_text">
4091
4092<h5>Syntax:</h5>
4093<pre>
4094 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4095</pre>
4096
4097<h5>Overview:</h5>
4098<p>The '<tt>fptosi</tt>' instruction converts
4099<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
4100</p>
4101
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4102<h5>Arguments:</h5>
4103<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]4104scalar or vector <a href="#t_floating">floating point</a> value, and a type
4105to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4106type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4107vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4108
4109<h5>Semantics:</h5>
4110<p>The '<tt>fptosi</tt>' instruction converts its
4111<a href="#t_floating">floating point</a> operand into the nearest (rounding
4112towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4113the results are undefined.</p>
4114
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4115<h5>Example:</h5>
4116<pre>
4117 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4118 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4119 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4120</pre>
4121</div>
4122
4123<!-- _______________________________________________________________________ -->
4124<div class="doc_subsubsection">
4125 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4126</div>
4127<div class="doc_text">
4128
4129<h5>Syntax:</h5>
4130<pre>
4131 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4132</pre>
4133
4134<h5>Overview:</h5>
4135<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4136integer and converts that value to the <tt>ty2</tt> type.</p>
4137
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4138<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4139<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4140scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4141to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4142type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4143floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4144
4145<h5>Semantics:</h5>
4146<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4147integer quantity and converts it to the corresponding floating point value. If
4148the value cannot fit in the floating point value, the results are undefined.</p>
4149
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4150<h5>Example:</h5>
4151<pre>
4152 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4153 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4154</pre>
4155</div>
4156
4157<!-- _______________________________________________________________________ -->
4158<div class="doc_subsubsection">
4159 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4160</div>
4161<div class="doc_text">
4162
4163<h5>Syntax:</h5>
4164<pre>
4165 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4166</pre>
4167
4168<h5>Overview:</h5>
4169<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4170integer and converts that value to the <tt>ty2</tt> type.</p>
4171
4172<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4173<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4174scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4175to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4176type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4177floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4178
4179<h5>Semantics:</h5>
4180<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4181integer quantity and converts it to the corresponding floating point value. If
4182the value cannot fit in the floating point value, the results are undefined.</p>
4183
4184<h5>Example:</h5>
4185<pre>
4186 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4187 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4188</pre>
4189</div>
4190
4191<!-- _______________________________________________________________________ -->
4192<div class="doc_subsubsection">
4193 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4194</div>
4195<div class="doc_text">
4196
4197<h5>Syntax:</h5>
4198<pre>
4199 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4200</pre>
4201
4202<h5>Overview:</h5>
4203<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4204the integer type <tt>ty2</tt>.</p>
4205
4206<h5>Arguments:</h5>
4207<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4208must 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]4209<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]4210
4211<h5>Semantics:</h5>
4212<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4213<tt>ty2</tt> by interpreting the pointer value as an integer and either
4214truncating or zero extending that value to the size of the integer type. If
4215<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4216<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4217are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4218change.</p>
4219
4220<h5>Example:</h5>
4221<pre>
4222 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4223 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4224</pre>
4225</div>
4226
4227<!-- _______________________________________________________________________ -->
4228<div class="doc_subsubsection">
4229 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4230</div>
4231<div class="doc_text">
4232
4233<h5>Syntax:</h5>
4234<pre>
4235 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4236</pre>
4237
4238<h5>Overview:</h5>
4239<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4240a pointer type, <tt>ty2</tt>.</p>
4241
4242<h5>Arguments:</h5>
4243<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4244value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4245<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246
4247<h5>Semantics:</h5>
4248<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4249<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4250the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4251size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4252the size of a pointer then a zero extension is done. If they are the same size,
4253nothing is done (<i>no-op cast</i>).</p>
4254
4255<h5>Example:</h5>
4256<pre>
4257 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4258 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4259 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4260</pre>
4261</div>
4262
4263<!-- _______________________________________________________________________ -->
4264<div class="doc_subsubsection">
4265 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4266</div>
4267<div class="doc_text">
4268
4269<h5>Syntax:</h5>
4270<pre>
4271 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4272</pre>
4273
4274<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4276<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4277<tt>ty2</tt> without changing any bits.</p>
4278
4279<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4281<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4282a non-aggregate first class value, and a type to cast it to, which must also be
4283a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4284<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4285and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4286type is a pointer, the destination type must also be a pointer. This
4287instruction supports bitwise conversion of vectors to integers and to vectors
4288of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4289
4290<h5>Semantics:</h5>
4291<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4292<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4293this conversion. The conversion is done as if the <tt>value</tt> had been
4294stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4295converted to other pointer types with this instruction. To convert pointers to
4296other types, use the <a href="#i_inttoptr">inttoptr</a> or
4297<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4298
4299<h5>Example:</h5>
4300<pre>
4301 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4302 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4303 %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]4304</pre>
4305</div>
4306
4307<!-- ======================================================================= -->
4308<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4309<div class="doc_text">
4310<p>The instructions in this category are the "miscellaneous"
4311instructions, which defy better classification.</p>
4312</div>
4313
4314<!-- _______________________________________________________________________ -->
4315<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4316</div>
4317<div class="doc_text">
4318<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4319<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]4320</pre>
4321<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4322<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4323a vector of boolean values based on comparison
4324of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4325<h5>Arguments:</h5>
4326<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4327the condition code indicating the kind of comparison to perform. It is not
4328a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4329</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4330<ol>
4331 <li><tt>eq</tt>: equal</li>
4332 <li><tt>ne</tt>: not equal </li>
4333 <li><tt>ugt</tt>: unsigned greater than</li>
4334 <li><tt>uge</tt>: unsigned greater or equal</li>
4335 <li><tt>ult</tt>: unsigned less than</li>
4336 <li><tt>ule</tt>: unsigned less or equal</li>
4337 <li><tt>sgt</tt>: signed greater than</li>
4338 <li><tt>sge</tt>: signed greater or equal</li>
4339 <li><tt>slt</tt>: signed less than</li>
4340 <li><tt>sle</tt>: signed less or equal</li>
4341</ol>
4342<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4343<a href="#t_pointer">pointer</a>
4344or integer <a href="#t_vector">vector</a> typed.
4345They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4346<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4347<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]4348the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4349yields 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]4350</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4351<ol>
4352 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4353 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4354 </li>
4355 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4356 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4357 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4358 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4360 <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]4361 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4362 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4363 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4364 <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]4365 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4366 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4367 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4368 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4370 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4371 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4372 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4373</ol>
4374<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4375values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4376<p>If the operands are integer vectors, then they are compared
4377element by element. The result is an <tt>i1</tt> vector with
4378the same number of elements as the values being compared.
4379Otherwise, the result is an <tt>i1</tt>.
4380</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4381
4382<h5>Example:</h5>
4383<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4384 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4385 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4386 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4387 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4388 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4389</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4390
4391<p>Note that the code generator does not yet support vector types with
4392 the <tt>icmp</tt> instruction.</p>
4393
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394</div>
4395
4396<!-- _______________________________________________________________________ -->
4397<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4398</div>
4399<div class="doc_text">
4400<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4401<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]4402</pre>
4403<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4404<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4405or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4406of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4407<p>
4408If the operands are floating point scalars, then the result
4409type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4410</p>
4411<p>If the operands are floating point vectors, then the result type
4412is a vector of boolean with the same number of elements as the
4413operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4414<h5>Arguments:</h5>
4415<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4416the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4417a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4418<ol>
4419 <li><tt>false</tt>: no comparison, always returns false</li>
4420 <li><tt>oeq</tt>: ordered and equal</li>
4421 <li><tt>ogt</tt>: ordered and greater than </li>
4422 <li><tt>oge</tt>: ordered and greater than or equal</li>
4423 <li><tt>olt</tt>: ordered and less than </li>
4424 <li><tt>ole</tt>: ordered and less than or equal</li>
4425 <li><tt>one</tt>: ordered and not equal</li>
4426 <li><tt>ord</tt>: ordered (no nans)</li>
4427 <li><tt>ueq</tt>: unordered or equal</li>
4428 <li><tt>ugt</tt>: unordered or greater than </li>
4429 <li><tt>uge</tt>: unordered or greater than or equal</li>
4430 <li><tt>ult</tt>: unordered or less than </li>
4431 <li><tt>ule</tt>: unordered or less than or equal</li>
4432 <li><tt>une</tt>: unordered or not equal</li>
4433 <li><tt>uno</tt>: unordered (either nans)</li>
4434 <li><tt>true</tt>: no comparison, always returns true</li>
4435</ol>
4436<p><i>Ordered</i> means that neither operand is a QNAN while
4437<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4438<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4439either a <a href="#t_floating">floating point</a> type
4440or a <a href="#t_vector">vector</a> of floating point type.
4441They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4442<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4443<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4444according to the condition code given as <tt>cond</tt>.
4445If the operands are vectors, then the vectors are compared
4446element by element.
4447Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4448always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4449<ol>
4450 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4451 <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]4452 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4453 <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]4454 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4455 <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]4456 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4457 <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]4458 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4459 <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]4460 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4461 <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]4462 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4463 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4464 <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]4465 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4466 <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]4467 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468 <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]4469 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4470 <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]4471 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4472 <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]4473 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4474 <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]4475 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4476 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4477 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4478</ol>
4479
4480<h5>Example:</h5>
4481<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]4482 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4483 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4484 &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]4485</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4486
4487<p>Note that the code generator does not yet support vector types with
4488 the <tt>fcmp</tt> instruction.</p>
4489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490</div>
4491
4492<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4493<div class="doc_subsubsection">
4494 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4495</div>
4496<div class="doc_text">
4497<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4498<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]4499</pre>
4500<h5>Overview:</h5>
4501<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4502element-wise comparison of its two integer vector operands.</p>
4503<h5>Arguments:</h5>
4504<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4505the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4506a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4507<ol>
4508 <li><tt>eq</tt>: equal</li>
4509 <li><tt>ne</tt>: not equal </li>
4510 <li><tt>ugt</tt>: unsigned greater than</li>
4511 <li><tt>uge</tt>: unsigned greater or equal</li>
4512 <li><tt>ult</tt>: unsigned less than</li>
4513 <li><tt>ule</tt>: unsigned less or equal</li>
4514 <li><tt>sgt</tt>: signed greater than</li>
4515 <li><tt>sge</tt>: signed greater or equal</li>
4516 <li><tt>slt</tt>: signed less than</li>
4517 <li><tt>sle</tt>: signed less or equal</li>
4518</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4519<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4520<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4521<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4522<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4523according to the condition code given as <tt>cond</tt>. The comparison yields a
4524<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4525identical type as the values being compared. The most significant bit in each
4526element is 1 if the element-wise comparison evaluates to true, and is 0
4527otherwise. All other bits of the result are undefined. The condition codes
4528are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4529instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4530
4531<h5>Example:</h5>
4532<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4533 &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>
4534 &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]4535</pre>
4536</div>
4537
4538<!-- _______________________________________________________________________ -->
4539<div class="doc_subsubsection">
4540 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4541</div>
4542<div class="doc_text">
4543<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4544<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]4545<h5>Overview:</h5>
4546<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4547element-wise comparison of its two floating point vector operands. The output
4548elements have the same width as the input elements.</p>
4549<h5>Arguments:</h5>
4550<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4551the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4552a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4553<ol>
4554 <li><tt>false</tt>: no comparison, always returns false</li>
4555 <li><tt>oeq</tt>: ordered and equal</li>
4556 <li><tt>ogt</tt>: ordered and greater than </li>
4557 <li><tt>oge</tt>: ordered and greater than or equal</li>
4558 <li><tt>olt</tt>: ordered and less than </li>
4559 <li><tt>ole</tt>: ordered and less than or equal</li>
4560 <li><tt>one</tt>: ordered and not equal</li>
4561 <li><tt>ord</tt>: ordered (no nans)</li>
4562 <li><tt>ueq</tt>: unordered or equal</li>
4563 <li><tt>ugt</tt>: unordered or greater than </li>
4564 <li><tt>uge</tt>: unordered or greater than or equal</li>
4565 <li><tt>ult</tt>: unordered or less than </li>
4566 <li><tt>ule</tt>: unordered or less than or equal</li>
4567 <li><tt>une</tt>: unordered or not equal</li>
4568 <li><tt>uno</tt>: unordered (either nans)</li>
4569 <li><tt>true</tt>: no comparison, always returns true</li>
4570</ol>
4571<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4572<a href="#t_floating">floating point</a> typed. They must also be identical
4573types.</p>
4574<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4575<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4576according to the condition code given as <tt>cond</tt>. The comparison yields a
4577<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4578an identical number of elements as the values being compared, and each element
4579having identical with to the width of the floating point elements. The most
4580significant bit in each element is 1 if the element-wise comparison evaluates to
4581true, and is 0 otherwise. All other bits of the result are undefined. The
4582condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4583<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4584
4585<h5>Example:</h5>
4586<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4587 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4588 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4589
4590 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4591 &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]4592</pre>
4593</div>
4594
4595<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4596<div class="doc_subsubsection">
4597 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4598</div>
4599
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4600<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4601
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4602<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4604<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4605<h5>Overview:</h5>
4606<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4607the SSA graph representing the function.</p>
4608<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4609
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4610<p>The type of the incoming values is specified with the first type
4611field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4612as arguments, with one pair for each predecessor basic block of the
4613current block. Only values of <a href="#t_firstclass">first class</a>
4614type may be used as the value arguments to the PHI node. Only labels
4615may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4616
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4617<p>There must be no non-phi instructions between the start of a basic
4618block and the PHI instructions: i.e. PHI instructions must be first in
4619a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4620
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4621<p>For the purposes of the SSA form, the use of each incoming value is
4622deemed to occur on the edge from the corresponding predecessor block
4623to the current block (but after any definition of an '<tt>invoke</tt>'
4624instruction's return value on the same edge).</p>
4625
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4626<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4627
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4628<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4629specified by the pair corresponding to the predecessor basic block that executed
4630just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4631
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4632<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4633<pre>
4634Loop: ; Infinite loop that counts from 0 on up...
4635 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4636 %nextindvar = add i32 %indvar, 1
4637 br label %Loop
4638</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4639</div>
4640
4641<!-- _______________________________________________________________________ -->
4642<div class="doc_subsubsection">
4643 <a name="i_select">'<tt>select</tt>' Instruction</a>
4644</div>
4645
4646<div class="doc_text">
4647
4648<h5>Syntax:</h5>
4649
4650<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4651 &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>
4652
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4653 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4654</pre>
4655
4656<h5>Overview:</h5>
4657
4658<p>
4659The '<tt>select</tt>' instruction is used to choose one value based on a
4660condition, without branching.
4661</p>
4662
4663
4664<h5>Arguments:</h5>
4665
4666<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4667The '<tt>select</tt>' instruction requires an 'i1' value or
4668a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4669condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4670type. If the val1/val2 are vectors and
4671the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4672individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4673</p>
4674
4675<h5>Semantics:</h5>
4676
4677<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4678If 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]4679value argument; otherwise, it returns the second value argument.
4680</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4681<p>
4682If the condition is a vector of i1, then the value arguments must
4683be vectors of the same size, and the selection is done element
4684by element.
4685</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686
4687<h5>Example:</h5>
4688
4689<pre>
4690 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4691</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4692
4693<p>Note that the code generator does not yet support conditions
4694 with vector type.</p>
4695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4696</div>
4697
4698
4699<!-- _______________________________________________________________________ -->
4700<div class="doc_subsubsection">
4701 <a name="i_call">'<tt>call</tt>' Instruction</a>
4702</div>
4703
4704<div class="doc_text">
4705
4706<h5>Syntax:</h5>
4707<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4708 &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]4709</pre>
4710
4711<h5>Overview:</h5>
4712
4713<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4714
4715<h5>Arguments:</h5>
4716
4717<p>This instruction requires several arguments:</p>
4718
4719<ol>
4720 <li>
4721 <p>The optional "tail" marker indicates whether the callee function accesses
4722 any allocas or varargs in the caller. If the "tail" marker is present, the
4723 function call is eligible for tail call optimization. Note that calls may
4724 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4725 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726 </li>
4727 <li>
4728 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4729 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4730 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4731 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4732
4733 <li>
4734 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4735 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4736 and '<tt>inreg</tt>' attributes are valid here.</p>
4737 </li>
4738
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4739 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4740 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4741 the type of the return value. Functions that return no value are marked
4742 <tt><a href="#t_void">void</a></tt>.</p>
4743 </li>
4744 <li>
4745 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4746 value being invoked. The argument types must match the types implied by
4747 this signature. This type can be omitted if the function is not varargs
4748 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4749 </li>
4750 <li>
4751 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4752 be invoked. In most cases, this is a direct function invocation, but
4753 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4754 to function value.</p>
4755 </li>
4756 <li>
4757 <p>'<tt>function args</tt>': argument list whose types match the
4758 function signature argument types. All arguments must be of
4759 <a href="#t_firstclass">first class</a> type. If the function signature
4760 indicates the function accepts a variable number of arguments, the extra
4761 arguments can be specified.</p>
4762 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4763 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4764 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4765 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4766 '<tt>readnone</tt>' attributes are valid here.</p>
4767 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4768</ol>
4769
4770<h5>Semantics:</h5>
4771
4772<p>The '<tt>call</tt>' instruction is used to cause control flow to
4773transfer to a specified function, with its incoming arguments bound to
4774the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4775instruction in the called function, control flow continues with the
4776instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4777function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4778
4779<h5>Example:</h5>
4780
4781<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4782 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4783 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4784 %X = tail call i32 @foo() <i>; yields i32</i>
4785 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4786 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4787
4788 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4789 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4790 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4791 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4792 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4793 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4794</pre>
4795
4796</div>
4797
4798<!-- _______________________________________________________________________ -->
4799<div class="doc_subsubsection">
4800 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4801</div>
4802
4803<div class="doc_text">
4804
4805<h5>Syntax:</h5>
4806
4807<pre>
4808 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4809</pre>
4810
4811<h5>Overview:</h5>
4812
4813<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4814the "variable argument" area of a function call. It is used to implement the
4815<tt>va_arg</tt> macro in C.</p>
4816
4817<h5>Arguments:</h5>
4818
4819<p>This instruction takes a <tt>va_list*</tt> value and the type of
4820the argument. It returns a value of the specified argument type and
4821increments the <tt>va_list</tt> to point to the next argument. The
4822actual type of <tt>va_list</tt> is target specific.</p>
4823
4824<h5>Semantics:</h5>
4825
4826<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4827type from the specified <tt>va_list</tt> and causes the
4828<tt>va_list</tt> to point to the next argument. For more information,
4829see the variable argument handling <a href="#int_varargs">Intrinsic
4830Functions</a>.</p>
4831
4832<p>It is legal for this instruction to be called in a function which does not
4833take a variable number of arguments, for example, the <tt>vfprintf</tt>
4834function.</p>
4835
4836<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4837href="#intrinsics">intrinsic function</a> because it takes a type as an
4838argument.</p>
4839
4840<h5>Example:</h5>
4841
4842<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4843
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4844<p>Note that the code generator does not yet fully support va_arg
4845 on many targets. Also, it does not currently support va_arg with
4846 aggregate types on any target.</p>
4847
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4848</div>
4849
4850<!-- *********************************************************************** -->
4851<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4852<!-- *********************************************************************** -->
4853
4854<div class="doc_text">
4855
4856<p>LLVM supports the notion of an "intrinsic function". These functions have
4857well known names and semantics and are required to follow certain restrictions.
4858Overall, these intrinsics represent an extension mechanism for the LLVM
4859language that does not require changing all of the transformations in LLVM when
4860adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4861
4862<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4863prefix is reserved in LLVM for intrinsic names; thus, function names may not
4864begin with this prefix. Intrinsic functions must always be external functions:
4865you cannot define the body of intrinsic functions. Intrinsic functions may
4866only be used in call or invoke instructions: it is illegal to take the address
4867of an intrinsic function. Additionally, because intrinsic functions are part
4868of the LLVM language, it is required if any are added that they be documented
4869here.</p>
4870
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4871<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4872a family of functions that perform the same operation but on different data
4873types. Because LLVM can represent over 8 million different integer types,
4874overloading is used commonly to allow an intrinsic function to operate on any
4875integer type. One or more of the argument types or the result type can be
4876overloaded to accept any integer type. Argument types may also be defined as
4877exactly matching a previous argument's type or the result type. This allows an
4878intrinsic function which accepts multiple arguments, but needs all of them to
4879be of the same type, to only be overloaded with respect to a single argument or
4880the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4881
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4882<p>Overloaded intrinsics will have the names of its overloaded argument types
4883encoded into its function name, each preceded by a period. Only those types
4884which are overloaded result in a name suffix. Arguments whose type is matched
4885against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4886take an integer of any width and returns an integer of exactly the same integer
4887width. This leads to a family of functions such as
4888<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4889Only one type, the return type, is overloaded, and only one type suffix is
4890required. Because the argument's type is matched against the return type, it
4891does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4892
4893<p>To learn how to add an intrinsic function, please see the
4894<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4895</p>
4896
4897</div>
4898
4899<!-- ======================================================================= -->
4900<div class="doc_subsection">
4901 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4902</div>
4903
4904<div class="doc_text">
4905
4906<p>Variable argument support is defined in LLVM with the <a
4907 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4908intrinsic functions. These functions are related to the similarly
4909named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4910
4911<p>All of these functions operate on arguments that use a
4912target-specific value type "<tt>va_list</tt>". The LLVM assembly
4913language reference manual does not define what this type is, so all
4914transformations should be prepared to handle these functions regardless of
4915the type used.</p>
4916
4917<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4918instruction and the variable argument handling intrinsic functions are
4919used.</p>
4920
4921<div class="doc_code">
4922<pre>
4923define i32 @test(i32 %X, ...) {
4924 ; Initialize variable argument processing
4925 %ap = alloca i8*
4926 %ap2 = bitcast i8** %ap to i8*
4927 call void @llvm.va_start(i8* %ap2)
4928
4929 ; Read a single integer argument
4930 %tmp = va_arg i8** %ap, i32
4931
4932 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4933 %aq = alloca i8*
4934 %aq2 = bitcast i8** %aq to i8*
4935 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4936 call void @llvm.va_end(i8* %aq2)
4937
4938 ; Stop processing of arguments.
4939 call void @llvm.va_end(i8* %ap2)
4940 ret i32 %tmp
4941}
4942
4943declare void @llvm.va_start(i8*)
4944declare void @llvm.va_copy(i8*, i8*)
4945declare void @llvm.va_end(i8*)
4946</pre>
4947</div>
4948
4949</div>
4950
4951<!-- _______________________________________________________________________ -->
4952<div class="doc_subsubsection">
4953 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4954</div>
4955
4956
4957<div class="doc_text">
4958<h5>Syntax:</h5>
4959<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4960<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4961<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4962<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4963href="#i_va_arg">va_arg</a></tt>.</p>
4964
4965<h5>Arguments:</h5>
4966
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4967<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]4968
4969<h5>Semantics:</h5>
4970
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4971<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]4972macro available in C. In a target-dependent way, it initializes the
4973<tt>va_list</tt> element to which the argument points, so that the next call to
4974<tt>va_arg</tt> will produce the first variable argument passed to the function.
4975Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4976last argument of the function as the compiler can figure that out.</p>
4977
4978</div>
4979
4980<!-- _______________________________________________________________________ -->
4981<div class="doc_subsubsection">
4982 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4983</div>
4984
4985<div class="doc_text">
4986<h5>Syntax:</h5>
4987<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4988<h5>Overview:</h5>
4989
4990<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4991which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4992or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4993
4994<h5>Arguments:</h5>
4995
4996<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4997
4998<h5>Semantics:</h5>
4999
5000<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
5001macro available in C. In a target-dependent way, it destroys the
5002<tt>va_list</tt> element to which the argument points. Calls to <a
5003href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
5004<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
5005<tt>llvm.va_end</tt>.</p>
5006
5007</div>
5008
5009<!-- _______________________________________________________________________ -->
5010<div class="doc_subsubsection">
5011 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5012</div>
5013
5014<div class="doc_text">
5015
5016<h5>Syntax:</h5>
5017
5018<pre>
5019 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5020</pre>
5021
5022<h5>Overview:</h5>
5023
5024<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
5025from the source argument list to the destination argument list.</p>
5026
5027<h5>Arguments:</h5>
5028
5029<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
5030The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
5031
5032
5033<h5>Semantics:</h5>
5034
5035<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
5036macro available in C. In a target-dependent way, it copies the source
5037<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
5038intrinsic is necessary because the <tt><a href="#int_va_start">
5039llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
5040example, memory allocation.</p>
5041
5042</div>
5043
5044<!-- ======================================================================= -->
5045<div class="doc_subsection">
5046 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5047</div>
5048
5049<div class="doc_text">
5050
5051<p>
5052LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5053Collection</a> (GC) requires the implementation and generation of these
5054intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5055These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
5056stack</a>, as well as garbage collector implementations that require <a
5057href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
5058Front-ends for type-safe garbage collected languages should generate these
5059intrinsics to make use of the LLVM garbage collectors. For more details, see <a
5060href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
5061</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5062
5063<p>The garbage collection intrinsics only operate on objects in the generic
5064 address space (address space zero).</p>
5065
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5066</div>
5067
5068<!-- _______________________________________________________________________ -->
5069<div class="doc_subsubsection">
5070 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5071</div>
5072
5073<div class="doc_text">
5074
5075<h5>Syntax:</h5>
5076
5077<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5078 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5079</pre>
5080
5081<h5>Overview:</h5>
5082
5083<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
5084the code generator, and allows some metadata to be associated with it.</p>
5085
5086<h5>Arguments:</h5>
5087
5088<p>The first argument specifies the address of a stack object that contains the
5089root pointer. The second pointer (which must be either a constant or a global
5090value address) contains the meta-data to be associated with the root.</p>
5091
5092<h5>Semantics:</h5>
5093
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5094<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]5095location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5096the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5097intrinsic may only be used in a function which <a href="#gc">specifies a GC
5098algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5099
5100</div>
5101
5102
5103<!-- _______________________________________________________________________ -->
5104<div class="doc_subsubsection">
5105 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5106</div>
5107
5108<div class="doc_text">
5109
5110<h5>Syntax:</h5>
5111
5112<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5113 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5114</pre>
5115
5116<h5>Overview:</h5>
5117
5118<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
5119locations, allowing garbage collector implementations that require read
5120barriers.</p>
5121
5122<h5>Arguments:</h5>
5123
5124<p>The second argument is the address to read from, which should be an address
5125allocated from the garbage collector. The first object is a pointer to the
5126start of the referenced object, if needed by the language runtime (otherwise
5127null).</p>
5128
5129<h5>Semantics:</h5>
5130
5131<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5132instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5133garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5134may only be used in a function which <a href="#gc">specifies a GC
5135algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5136
5137</div>
5138
5139
5140<!-- _______________________________________________________________________ -->
5141<div class="doc_subsubsection">
5142 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5143</div>
5144
5145<div class="doc_text">
5146
5147<h5>Syntax:</h5>
5148
5149<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5150 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5151</pre>
5152
5153<h5>Overview:</h5>
5154
5155<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5156locations, allowing garbage collector implementations that require write
5157barriers (such as generational or reference counting collectors).</p>
5158
5159<h5>Arguments:</h5>
5160
5161<p>The first argument is the reference to store, the second is the start of the
5162object to store it to, and the third is the address of the field of Obj to
5163store to. If the runtime does not require a pointer to the object, Obj may be
5164null.</p>
5165
5166<h5>Semantics:</h5>
5167
5168<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5169instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5170garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5171may only be used in a function which <a href="#gc">specifies a GC
5172algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5173
5174</div>
5175
5176
5177
5178<!-- ======================================================================= -->
5179<div class="doc_subsection">
5180 <a name="int_codegen">Code Generator Intrinsics</a>
5181</div>
5182
5183<div class="doc_text">
5184<p>
5185These intrinsics are provided by LLVM to expose special features that may only
5186be implemented with code generator support.
5187</p>
5188
5189</div>
5190
5191<!-- _______________________________________________________________________ -->
5192<div class="doc_subsubsection">
5193 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5194</div>
5195
5196<div class="doc_text">
5197
5198<h5>Syntax:</h5>
5199<pre>
5200 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5201</pre>
5202
5203<h5>Overview:</h5>
5204
5205<p>
5206The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5207target-specific value indicating the return address of the current function
5208or one of its callers.
5209</p>
5210
5211<h5>Arguments:</h5>
5212
5213<p>
5214The argument to this intrinsic indicates which function to return the address
5215for. Zero indicates the calling function, one indicates its caller, etc. The
5216argument is <b>required</b> to be a constant integer value.
5217</p>
5218
5219<h5>Semantics:</h5>
5220
5221<p>
5222The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5223the return address of the specified call frame, or zero if it cannot be
5224identified. The value returned by this intrinsic is likely to be incorrect or 0
5225for arguments other than zero, so it should only be used for debugging purposes.
5226</p>
5227
5228<p>
5229Note that calling this intrinsic does not prevent function inlining or other
5230aggressive transformations, so the value returned may not be that of the obvious
5231source-language caller.
5232</p>
5233</div>
5234
5235
5236<!-- _______________________________________________________________________ -->
5237<div class="doc_subsubsection">
5238 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5239</div>
5240
5241<div class="doc_text">
5242
5243<h5>Syntax:</h5>
5244<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5245 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5246</pre>
5247
5248<h5>Overview:</h5>
5249
5250<p>
5251The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5252target-specific frame pointer value for the specified stack frame.
5253</p>
5254
5255<h5>Arguments:</h5>
5256
5257<p>
5258The argument to this intrinsic indicates which function to return the frame
5259pointer for. Zero indicates the calling function, one indicates its caller,
5260etc. The argument is <b>required</b> to be a constant integer value.
5261</p>
5262
5263<h5>Semantics:</h5>
5264
5265<p>
5266The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5267the frame address of the specified call frame, or zero if it cannot be
5268identified. The value returned by this intrinsic is likely to be incorrect or 0
5269for arguments other than zero, so it should only be used for debugging purposes.
5270</p>
5271
5272<p>
5273Note that calling this intrinsic does not prevent function inlining or other
5274aggressive transformations, so the value returned may not be that of the obvious
5275source-language caller.
5276</p>
5277</div>
5278
5279<!-- _______________________________________________________________________ -->
5280<div class="doc_subsubsection">
5281 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5282</div>
5283
5284<div class="doc_text">
5285
5286<h5>Syntax:</h5>
5287<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5288 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289</pre>
5290
5291<h5>Overview:</h5>
5292
5293<p>
5294The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5295the function stack, for use with <a href="#int_stackrestore">
5296<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5297features like scoped automatic variable sized arrays in C99.
5298</p>
5299
5300<h5>Semantics:</h5>
5301
5302<p>
5303This intrinsic returns a opaque pointer value that can be passed to <a
5304href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5305<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5306<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5307state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5308practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5309that were allocated after the <tt>llvm.stacksave</tt> was executed.
5310</p>
5311
5312</div>
5313
5314<!-- _______________________________________________________________________ -->
5315<div class="doc_subsubsection">
5316 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5317</div>
5318
5319<div class="doc_text">
5320
5321<h5>Syntax:</h5>
5322<pre>
5323 declare void @llvm.stackrestore(i8 * %ptr)
5324</pre>
5325
5326<h5>Overview:</h5>
5327
5328<p>
5329The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5330the function stack to the state it was in when the corresponding <a
5331href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5332useful for implementing language features like scoped automatic variable sized
5333arrays in C99.
5334</p>
5335
5336<h5>Semantics:</h5>
5337
5338<p>
5339See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5340</p>
5341
5342</div>
5343
5344
5345<!-- _______________________________________________________________________ -->
5346<div class="doc_subsubsection">
5347 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5348</div>
5349
5350<div class="doc_text">
5351
5352<h5>Syntax:</h5>
5353<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5354 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]5355</pre>
5356
5357<h5>Overview:</h5>
5358
5359
5360<p>
5361The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5362a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5363no
5364effect on the behavior of the program but can change its performance
5365characteristics.
5366</p>
5367
5368<h5>Arguments:</h5>
5369
5370<p>
5371<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5372determining if the fetch should be for a read (0) or write (1), and
5373<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5374locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5375<tt>locality</tt> arguments must be constant integers.
5376</p>
5377
5378<h5>Semantics:</h5>
5379
5380<p>
5381This intrinsic does not modify the behavior of the program. In particular,
5382prefetches cannot trap and do not produce a value. On targets that support this
5383intrinsic, the prefetch can provide hints to the processor cache for better
5384performance.
5385</p>
5386
5387</div>
5388
5389<!-- _______________________________________________________________________ -->
5390<div class="doc_subsubsection">
5391 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5392</div>
5393
5394<div class="doc_text">
5395
5396<h5>Syntax:</h5>
5397<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5398 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5399</pre>
5400
5401<h5>Overview:</h5>
5402
5403
5404<p>
5405The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5406(PC) in a region of
5407code to simulators and other tools. The method is target specific, but it is
5408expected that the marker will use exported symbols to transmit the PC of the
5409marker.
5410The marker makes no guarantees that it will remain with any specific instruction
5411after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5412optimizations. The intended use is to be inserted after optimizations to allow
5413correlations of simulation runs.
5414</p>
5415
5416<h5>Arguments:</h5>
5417
5418<p>
5419<tt>id</tt> is a numerical id identifying the marker.
5420</p>
5421
5422<h5>Semantics:</h5>
5423
5424<p>
5425This intrinsic does not modify the behavior of the program. Backends that do not
5426support this intrinisic may ignore it.
5427</p>
5428
5429</div>
5430
5431<!-- _______________________________________________________________________ -->
5432<div class="doc_subsubsection">
5433 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5434</div>
5435
5436<div class="doc_text">
5437
5438<h5>Syntax:</h5>
5439<pre>
5440 declare i64 @llvm.readcyclecounter( )
5441</pre>
5442
5443<h5>Overview:</h5>
5444
5445
5446<p>
5447The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5448counter register (or similar low latency, high accuracy clocks) on those targets
5449that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5450As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5451should only be used for small timings.
5452</p>
5453
5454<h5>Semantics:</h5>
5455
5456<p>
5457When directly supported, reading the cycle counter should not modify any memory.
5458Implementations are allowed to either return a application specific value or a
5459system wide value. On backends without support, this is lowered to a constant 0.
5460</p>
5461
5462</div>
5463
5464<!-- ======================================================================= -->
5465<div class="doc_subsection">
5466 <a name="int_libc">Standard C Library Intrinsics</a>
5467</div>
5468
5469<div class="doc_text">
5470<p>
5471LLVM provides intrinsics for a few important standard C library functions.
5472These intrinsics allow source-language front-ends to pass information about the
5473alignment of the pointer arguments to the code generator, providing opportunity
5474for more efficient code generation.
5475</p>
5476
5477</div>
5478
5479<!-- _______________________________________________________________________ -->
5480<div class="doc_subsubsection">
5481 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5482</div>
5483
5484<div class="doc_text">
5485
5486<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5487<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5488width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5489<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5490 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5491 i8 &lt;len&gt;, i32 &lt;align&gt;)
5492 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5493 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5494 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5495 i32 &lt;len&gt;, i32 &lt;align&gt;)
5496 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5497 i64 &lt;len&gt;, i32 &lt;align&gt;)
5498</pre>
5499
5500<h5>Overview:</h5>
5501
5502<p>
5503The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5504location to the destination location.
5505</p>
5506
5507<p>
5508Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5509intrinsics do not return a value, and takes an extra alignment argument.
5510</p>
5511
5512<h5>Arguments:</h5>
5513
5514<p>
5515The first argument is a pointer to the destination, the second is a pointer to
5516the source. The third argument is an integer argument
5517specifying the number of bytes to copy, and the fourth argument is the alignment
5518of the source and destination locations.
5519</p>
5520
5521<p>
5522If the call to this intrinisic has an alignment value that is not 0 or 1, then
5523the caller guarantees that both the source and destination pointers are aligned
5524to that boundary.
5525</p>
5526
5527<h5>Semantics:</h5>
5528
5529<p>
5530The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5531location to the destination location, which are not allowed to overlap. It
5532copies "len" bytes of memory over. If the argument is known to be aligned to
5533some boundary, this can be specified as the fourth argument, otherwise it should
5534be set to 0 or 1.
5535</p>
5536</div>
5537
5538
5539<!-- _______________________________________________________________________ -->
5540<div class="doc_subsubsection">
5541 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5542</div>
5543
5544<div class="doc_text">
5545
5546<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5547<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5548width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5549<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5550 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5551 i8 &lt;len&gt;, i32 &lt;align&gt;)
5552 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5553 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5555 i32 &lt;len&gt;, i32 &lt;align&gt;)
5556 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5557 i64 &lt;len&gt;, i32 &lt;align&gt;)
5558</pre>
5559
5560<h5>Overview:</h5>
5561
5562<p>
5563The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5564location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5565'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566</p>
5567
5568<p>
5569Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5570intrinsics do not return a value, and takes an extra alignment argument.
5571</p>
5572
5573<h5>Arguments:</h5>
5574
5575<p>
5576The first argument is a pointer to the destination, the second is a pointer to
5577the source. The third argument is an integer argument
5578specifying the number of bytes to copy, and the fourth argument is the alignment
5579of the source and destination locations.
5580</p>
5581
5582<p>
5583If the call to this intrinisic has an alignment value that is not 0 or 1, then
5584the caller guarantees that the source and destination pointers are aligned to
5585that boundary.
5586</p>
5587
5588<h5>Semantics:</h5>
5589
5590<p>
5591The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5592location to the destination location, which may overlap. It
5593copies "len" bytes of memory over. If the argument is known to be aligned to
5594some boundary, this can be specified as the fourth argument, otherwise it should
5595be set to 0 or 1.
5596</p>
5597</div>
5598
5599
5600<!-- _______________________________________________________________________ -->
5601<div class="doc_subsubsection">
5602 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5603</div>
5604
5605<div class="doc_text">
5606
5607<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5608<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5609width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5610<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5611 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5612 i8 &lt;len&gt;, i32 &lt;align&gt;)
5613 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5614 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5615 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5616 i32 &lt;len&gt;, i32 &lt;align&gt;)
5617 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5618 i64 &lt;len&gt;, i32 &lt;align&gt;)
5619</pre>
5620
5621<h5>Overview:</h5>
5622
5623<p>
5624The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5625byte value.
5626</p>
5627
5628<p>
5629Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5630does not return a value, and takes an extra alignment argument.
5631</p>
5632
5633<h5>Arguments:</h5>
5634
5635<p>
5636The first argument is a pointer to the destination to fill, the second is the
5637byte value to fill it with, the third argument is an integer
5638argument specifying the number of bytes to fill, and the fourth argument is the
5639known alignment of destination location.
5640</p>
5641
5642<p>
5643If the call to this intrinisic has an alignment value that is not 0 or 1, then
5644the caller guarantees that the destination pointer is aligned to that boundary.
5645</p>
5646
5647<h5>Semantics:</h5>
5648
5649<p>
5650The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5651the
5652destination location. If the argument is known to be aligned to some boundary,
5653this can be specified as the fourth argument, otherwise it should be set to 0 or
56541.
5655</p>
5656</div>
5657
5658
5659<!-- _______________________________________________________________________ -->
5660<div class="doc_subsubsection">
5661 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5662</div>
5663
5664<div class="doc_text">
5665
5666<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5667<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]5668floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5669types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5670<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5671 declare float @llvm.sqrt.f32(float %Val)
5672 declare double @llvm.sqrt.f64(double %Val)
5673 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5674 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5675 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5676</pre>
5677
5678<h5>Overview:</h5>
5679
5680<p>
5681The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5682returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5683<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5684negative numbers other than -0.0 (which allows for better optimization, because
5685there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5686defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5687</p>
5688
5689<h5>Arguments:</h5>
5690
5691<p>
5692The argument and return value are floating point numbers of the same type.
5693</p>
5694
5695<h5>Semantics:</h5>
5696
5697<p>
5698This function returns the sqrt of the specified operand if it is a nonnegative
5699floating point number.
5700</p>
5701</div>
5702
5703<!-- _______________________________________________________________________ -->
5704<div class="doc_subsubsection">
5705 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5706</div>
5707
5708<div class="doc_text">
5709
5710<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5711<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]5712floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5713types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5714<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5715 declare float @llvm.powi.f32(float %Val, i32 %power)
5716 declare double @llvm.powi.f64(double %Val, i32 %power)
5717 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5718 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5719 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5720</pre>
5721
5722<h5>Overview:</h5>
5723
5724<p>
5725The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5726specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5727multiplications is not defined. When a vector of floating point type is
5728used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5729</p>
5730
5731<h5>Arguments:</h5>
5732
5733<p>
5734The second argument is an integer power, and the first is a value to raise to
5735that power.
5736</p>
5737
5738<h5>Semantics:</h5>
5739
5740<p>
5741This function returns the first value raised to the second power with an
5742unspecified sequence of rounding operations.</p>
5743</div>
5744
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5745<!-- _______________________________________________________________________ -->
5746<div class="doc_subsubsection">
5747 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5748</div>
5749
5750<div class="doc_text">
5751
5752<h5>Syntax:</h5>
5753<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5754floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5755types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5756<pre>
5757 declare float @llvm.sin.f32(float %Val)
5758 declare double @llvm.sin.f64(double %Val)
5759 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5760 declare fp128 @llvm.sin.f128(fp128 %Val)
5761 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5762</pre>
5763
5764<h5>Overview:</h5>
5765
5766<p>
5767The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5768</p>
5769
5770<h5>Arguments:</h5>
5771
5772<p>
5773The argument and return value are floating point numbers of the same type.
5774</p>
5775
5776<h5>Semantics:</h5>
5777
5778<p>
5779This function returns the sine of the specified operand, returning the
5780same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5781conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5782</div>
5783
5784<!-- _______________________________________________________________________ -->
5785<div class="doc_subsubsection">
5786 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5787</div>
5788
5789<div class="doc_text">
5790
5791<h5>Syntax:</h5>
5792<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5793floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5794types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5795<pre>
5796 declare float @llvm.cos.f32(float %Val)
5797 declare double @llvm.cos.f64(double %Val)
5798 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5799 declare fp128 @llvm.cos.f128(fp128 %Val)
5800 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5801</pre>
5802
5803<h5>Overview:</h5>
5804
5805<p>
5806The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5807</p>
5808
5809<h5>Arguments:</h5>
5810
5811<p>
5812The argument and return value are floating point numbers of the same type.
5813</p>
5814
5815<h5>Semantics:</h5>
5816
5817<p>
5818This function returns the cosine of the specified operand, returning the
5819same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5820conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5821</div>
5822
5823<!-- _______________________________________________________________________ -->
5824<div class="doc_subsubsection">
5825 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5826</div>
5827
5828<div class="doc_text">
5829
5830<h5>Syntax:</h5>
5831<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5832floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5833types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5834<pre>
5835 declare float @llvm.pow.f32(float %Val, float %Power)
5836 declare double @llvm.pow.f64(double %Val, double %Power)
5837 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5838 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5839 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5840</pre>
5841
5842<h5>Overview:</h5>
5843
5844<p>
5845The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5846specified (positive or negative) power.
5847</p>
5848
5849<h5>Arguments:</h5>
5850
5851<p>
5852The second argument is a floating point power, and the first is a value to
5853raise to that power.
5854</p>
5855
5856<h5>Semantics:</h5>
5857
5858<p>
5859This function returns the first value raised to the second power,
5860returning the
5861same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5862conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5863</div>
5864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5865
5866<!-- ======================================================================= -->
5867<div class="doc_subsection">
5868 <a name="int_manip">Bit Manipulation Intrinsics</a>
5869</div>
5870
5871<div class="doc_text">
5872<p>
5873LLVM provides intrinsics for a few important bit manipulation operations.
5874These allow efficient code generation for some algorithms.
5875</p>
5876
5877</div>
5878
5879<!-- _______________________________________________________________________ -->
5880<div class="doc_subsubsection">
5881 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5882</div>
5883
5884<div class="doc_text">
5885
5886<h5>Syntax:</h5>
5887<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5888type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5889<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5890 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5891 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5892 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5893</pre>
5894
5895<h5>Overview:</h5>
5896
5897<p>
5898The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5899values with an even number of bytes (positive multiple of 16 bits). These are
5900useful for performing operations on data that is not in the target's native
5901byte order.
5902</p>
5903
5904<h5>Semantics:</h5>
5905
5906<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5907The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5908and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5909intrinsic returns an i32 value that has the four bytes of the input i32
5910swapped, 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]5911i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5912<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5913additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5914</p>
5915
5916</div>
5917
5918<!-- _______________________________________________________________________ -->
5919<div class="doc_subsubsection">
5920 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5921</div>
5922
5923<div class="doc_text">
5924
5925<h5>Syntax:</h5>
5926<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]5927width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5928<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5929 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5930 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5931 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5932 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5933 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5934</pre>
5935
5936<h5>Overview:</h5>
5937
5938<p>
5939The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5940value.
5941</p>
5942
5943<h5>Arguments:</h5>
5944
5945<p>
5946The only argument is the value to be counted. The argument may be of any
5947integer type. The return type must match the argument type.
5948</p>
5949
5950<h5>Semantics:</h5>
5951
5952<p>
5953The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5954</p>
5955</div>
5956
5957<!-- _______________________________________________________________________ -->
5958<div class="doc_subsubsection">
5959 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5960</div>
5961
5962<div class="doc_text">
5963
5964<h5>Syntax:</h5>
5965<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]5966integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5967<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5968 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5969 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5970 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5971 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5972 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5973</pre>
5974
5975<h5>Overview:</h5>
5976
5977<p>
5978The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5979leading zeros in a variable.
5980</p>
5981
5982<h5>Arguments:</h5>
5983
5984<p>
5985The only argument is the value to be counted. The argument may be of any
5986integer type. The return type must match the argument type.
5987</p>
5988
5989<h5>Semantics:</h5>
5990
5991<p>
5992The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5993in a variable. If the src == 0 then the result is the size in bits of the type
5994of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5995</p>
5996</div>
5997
5998
5999
6000<!-- _______________________________________________________________________ -->
6001<div class="doc_subsubsection">
6002 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6003</div>
6004
6005<div class="doc_text">
6006
6007<h5>Syntax:</h5>
6008<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]6009integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6010<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6011 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6012 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6013 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6014 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6015 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6016</pre>
6017
6018<h5>Overview:</h5>
6019
6020<p>
6021The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6022trailing zeros.
6023</p>
6024
6025<h5>Arguments:</h5>
6026
6027<p>
6028The only argument is the value to be counted. The argument may be of any
6029integer type. The return type must match the argument type.
6030</p>
6031
6032<h5>Semantics:</h5>
6033
6034<p>
6035The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
6036in a variable. If the src == 0 then the result is the size in bits of the type
6037of src. For example, <tt>llvm.cttz(2) = 1</tt>.
6038</p>
6039</div>
6040
6041<!-- _______________________________________________________________________ -->
6042<div class="doc_subsubsection">
6043 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
6044</div>
6045
6046<div class="doc_text">
6047
6048<h5>Syntax:</h5>
6049<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6050on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6051<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6052 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
6053 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6054</pre>
6055
6056<h5>Overview:</h5>
6057<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
6058range of bits from an integer value and returns them in the same bit width as
6059the original value.</p>
6060
6061<h5>Arguments:</h5>
6062<p>The first argument, <tt>%val</tt> and the result may be integer types of
6063any bit width but they must have the same bit width. The second and third
6064arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
6065
6066<h5>Semantics:</h5>
6067<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
6068of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
6069<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
6070operates in forward mode.</p>
6071<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
6072right by <tt>%loBit</tt> bits and then ANDing it with a mask with
6073only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
6074<ol>
6075 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
6076 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
6077 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
6078 to determine the number of bits to retain.</li>
6079 <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]6080 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6081</ol>
6082<p>In reverse mode, a similar computation is made except that the bits are
6083returned in the reverse order. So, for example, if <tt>X</tt> has the value
6084<tt>i16 0x0ACF (101011001111)</tt> and we apply
6085<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
6086<tt>i16 0x0026 (000000100110)</tt>.</p>
6087</div>
6088
6089<div class="doc_subsubsection">
6090 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
6091</div>
6092
6093<div class="doc_text">
6094
6095<h5>Syntax:</h5>
6096<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6097on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6098<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6099 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
6100 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]6101</pre>
6102
6103<h5>Overview:</h5>
6104<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
6105of bits in an integer value with another integer value. It returns the integer
6106with the replaced bits.</p>
6107
6108<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6109<p>The first argument, <tt>%val</tt>, and the result may be integer types of
6110any 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]6111whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
6112integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
6113type since they specify only a bit index.</p>
6114
6115<h5>Semantics:</h5>
6116<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
6117of operation: forwards and reverse. If <tt>%lo</tt> is greater than
6118<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
6119operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6120
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6121<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
6122truncating it down to the size of the replacement area or zero extending it
6123up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6124
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6125<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
6126are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
6127in <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]6128to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6129
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6130<p>In reverse mode, a similar computation is made except that the bits are
6131reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6132<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]6133
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6134<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6135
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6136<pre>
6137 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
6138 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
6139 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
6140 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
6141 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
6142</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6143
6144</div>
6145
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6146<!-- ======================================================================= -->
6147<div class="doc_subsection">
6148 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6149</div>
6150
6151<div class="doc_text">
6152<p>
6153LLVM provides intrinsics for some arithmetic with overflow operations.
6154</p>
6155
6156</div>
6157
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6158<!-- _______________________________________________________________________ -->
6159<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6160 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6161</div>
6162
6163<div class="doc_text">
6164
6165<h5>Syntax:</h5>
6166
6167<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]6168on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6169
6170<pre>
6171 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6172 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6173 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6174</pre>
6175
6176<h5>Overview:</h5>
6177
6178<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6179a signed addition of the two arguments, and indicate whether an overflow
6180occurred during the signed summation.</p>
6181
6182<h5>Arguments:</h5>
6183
6184<p>The arguments (%a and %b) and the first element of the result structure may
6185be of integer types of any bit width, but they must have the same bit width. The
6186second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6187and <tt>%b</tt> are the two values that will undergo signed addition.</p>
6188
6189<h5>Semantics:</h5>
6190
6191<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6192a signed addition of the two variables. They return a structure &mdash; the
6193first element of which is the signed summation, and the second element of which
6194is a bit specifying if the signed summation resulted in an overflow.</p>
6195
6196<h5>Examples:</h5>
6197<pre>
6198 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6199 %sum = extractvalue {i32, i1} %res, 0
6200 %obit = extractvalue {i32, i1} %res, 1
6201 br i1 %obit, label %overflow, label %normal
6202</pre>
6203
6204</div>
6205
6206<!-- _______________________________________________________________________ -->
6207<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6208 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6209</div>
6210
6211<div class="doc_text">
6212
6213<h5>Syntax:</h5>
6214
6215<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]6216on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6217
6218<pre>
6219 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6220 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6221 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6222</pre>
6223
6224<h5>Overview:</h5>
6225
6226<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6227an unsigned addition of the two arguments, and indicate whether a carry occurred
6228during the unsigned summation.</p>
6229
6230<h5>Arguments:</h5>
6231
6232<p>The arguments (%a and %b) and the first element of the result structure may
6233be of integer types of any bit width, but they must have the same bit width. The
6234second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6235and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6236
6237<h5>Semantics:</h5>
6238
6239<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6240an unsigned addition of the two arguments. They return a structure &mdash; the
6241first element of which is the sum, and the second element of which is a bit
6242specifying if the unsigned summation resulted in a carry.</p>
6243
6244<h5>Examples:</h5>
6245<pre>
6246 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6247 %sum = extractvalue {i32, i1} %res, 0
6248 %obit = extractvalue {i32, i1} %res, 1
6249 br i1 %obit, label %carry, label %normal
6250</pre>
6251
6252</div>
6253
6254<!-- _______________________________________________________________________ -->
6255<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6256 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6257</div>
6258
6259<div class="doc_text">
6260
6261<h5>Syntax:</h5>
6262
6263<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]6264on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6265
6266<pre>
6267 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6268 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6269 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6270</pre>
6271
6272<h5>Overview:</h5>
6273
6274<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6275a signed subtraction of the two arguments, and indicate whether an overflow
6276occurred during the signed subtraction.</p>
6277
6278<h5>Arguments:</h5>
6279
6280<p>The arguments (%a and %b) and the first element of the result structure may
6281be of integer types of any bit width, but they must have the same bit width. The
6282second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6283and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6284
6285<h5>Semantics:</h5>
6286
6287<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6288a signed subtraction of the two arguments. They return a structure &mdash; the
6289first element of which is the subtraction, and the second element of which is a bit
6290specifying if the signed subtraction resulted in an overflow.</p>
6291
6292<h5>Examples:</h5>
6293<pre>
6294 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6295 %sum = extractvalue {i32, i1} %res, 0
6296 %obit = extractvalue {i32, i1} %res, 1
6297 br i1 %obit, label %overflow, label %normal
6298</pre>
6299
6300</div>
6301
6302<!-- _______________________________________________________________________ -->
6303<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6304 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6305</div>
6306
6307<div class="doc_text">
6308
6309<h5>Syntax:</h5>
6310
6311<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]6312on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6313
6314<pre>
6315 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6316 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6317 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6318</pre>
6319
6320<h5>Overview:</h5>
6321
6322<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6323an unsigned subtraction of the two arguments, and indicate whether an overflow
6324occurred during the unsigned subtraction.</p>
6325
6326<h5>Arguments:</h5>
6327
6328<p>The arguments (%a and %b) and the first element of the result structure may
6329be of integer types of any bit width, but they must have the same bit width. The
6330second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6331and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6332
6333<h5>Semantics:</h5>
6334
6335<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6336an unsigned subtraction of the two arguments. They return a structure &mdash; the
6337first element of which is the subtraction, and the second element of which is a bit
6338specifying if the unsigned subtraction resulted in an overflow.</p>
6339
6340<h5>Examples:</h5>
6341<pre>
6342 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6343 %sum = extractvalue {i32, i1} %res, 0
6344 %obit = extractvalue {i32, i1} %res, 1
6345 br i1 %obit, label %overflow, label %normal
6346</pre>
6347
6348</div>
6349
6350<!-- _______________________________________________________________________ -->
6351<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6352 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6353</div>
6354
6355<div class="doc_text">
6356
6357<h5>Syntax:</h5>
6358
6359<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]6360on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6361
6362<pre>
6363 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6364 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6365 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6366</pre>
6367
6368<h5>Overview:</h5>
6369
6370<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6371a signed multiplication of the two arguments, and indicate whether an overflow
6372occurred during the signed multiplication.</p>
6373
6374<h5>Arguments:</h5>
6375
6376<p>The arguments (%a and %b) and the first element of the result structure may
6377be of integer types of any bit width, but they must have the same bit width. The
6378second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6379and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6380
6381<h5>Semantics:</h5>
6382
6383<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6384a signed multiplication of the two arguments. They return a structure &mdash;
6385the first element of which is the multiplication, and the second element of
6386which is a bit specifying if the signed multiplication resulted in an
6387overflow.</p>
6388
6389<h5>Examples:</h5>
6390<pre>
6391 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6392 %sum = extractvalue {i32, i1} %res, 0
6393 %obit = extractvalue {i32, i1} %res, 1
6394 br i1 %obit, label %overflow, label %normal
6395</pre>
6396
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6397</div>
6398
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6399<!-- _______________________________________________________________________ -->
6400<div class="doc_subsubsection">
6401 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6402</div>
6403
6404<div class="doc_text">
6405
6406<h5>Syntax:</h5>
6407
6408<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6409on any integer bit width.</p>
6410
6411<pre>
6412 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6413 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6414 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6415</pre>
6416
6417<h5>Overview:</h5>
6418
6419<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6420actively being fixed, but it should not currently be used!</i></p>
6421
6422<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6423a unsigned multiplication of the two arguments, and indicate whether an overflow
6424occurred during the unsigned multiplication.</p>
6425
6426<h5>Arguments:</h5>
6427
6428<p>The arguments (%a and %b) and the first element of the result structure may
6429be of integer types of any bit width, but they must have the same bit width. The
6430second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6431and <tt>%b</tt> are the two values that will undergo unsigned
6432multiplication.</p>
6433
6434<h5>Semantics:</h5>
6435
6436<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6437an unsigned multiplication of the two arguments. They return a structure &mdash;
6438the first element of which is the multiplication, and the second element of
6439which is a bit specifying if the unsigned multiplication resulted in an
6440overflow.</p>
6441
6442<h5>Examples:</h5>
6443<pre>
6444 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6445 %sum = extractvalue {i32, i1} %res, 0
6446 %obit = extractvalue {i32, i1} %res, 1
6447 br i1 %obit, label %overflow, label %normal
6448</pre>
6449
6450</div>
6451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6452<!-- ======================================================================= -->
6453<div class="doc_subsection">
6454 <a name="int_debugger">Debugger Intrinsics</a>
6455</div>
6456
6457<div class="doc_text">
6458<p>
6459The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6460are described in the <a
6461href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6462Debugging</a> document.
6463</p>
6464</div>
6465
6466
6467<!-- ======================================================================= -->
6468<div class="doc_subsection">
6469 <a name="int_eh">Exception Handling Intrinsics</a>
6470</div>
6471
6472<div class="doc_text">
6473<p> The LLVM exception handling intrinsics (which all start with
6474<tt>llvm.eh.</tt> prefix), are described in the <a
6475href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6476Handling</a> document. </p>
6477</div>
6478
6479<!-- ======================================================================= -->
6480<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6481 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6482</div>
6483
6484<div class="doc_text">
6485<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6486 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6487 the <tt>nest</tt> attribute, from a function. The result is a callable
6488 function pointer lacking the nest parameter - the caller does not need
6489 to provide a value for it. Instead, the value to use is stored in
6490 advance in a "trampoline", a block of memory usually allocated
6491 on the stack, which also contains code to splice the nest value into the
6492 argument list. This is used to implement the GCC nested function address
6493 extension.
6494</p>
6495<p>
6496 For example, if the function is
6497 <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]6498 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]6499<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6500 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6501 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6502 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6503 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6504</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6505 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6506 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6507</div>
6508
6509<!-- _______________________________________________________________________ -->
6510<div class="doc_subsubsection">
6511 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6512</div>
6513<div class="doc_text">
6514<h5>Syntax:</h5>
6515<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6516declare 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]6517</pre>
6518<h5>Overview:</h5>
6519<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6520 This fills the memory pointed to by <tt>tramp</tt> with code
6521 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6522</p>
6523<h5>Arguments:</h5>
6524<p>
6525 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6526 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6527 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6528 intrinsic. Note that the size and the alignment are target-specific - LLVM
6529 currently provides no portable way of determining them, so a front-end that
6530 generates this intrinsic needs to have some target-specific knowledge.
6531 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]6532</p>
6533<h5>Semantics:</h5>
6534<p>
6535 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6536 dependent code, turning it into a function. A pointer to this function is
6537 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6538 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6539 before being called. The new function's signature is the same as that of
6540 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6541 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6542 of pointer type. Calling the new function is equivalent to calling
6543 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6544 missing <tt>nest</tt> argument. If, after calling
6545 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6546 modified, then the effect of any later call to the returned function pointer is
6547 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6548</p>
6549</div>
6550
6551<!-- ======================================================================= -->
6552<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6553 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6554</div>
6555
6556<div class="doc_text">
6557<p>
6558 These intrinsic functions expand the "universal IR" of LLVM to represent
6559 hardware constructs for atomic operations and memory synchronization. This
6560 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6561 is aimed at a low enough level to allow any programming models or APIs
6562 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6563 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6564 hardware behavior. Just as hardware provides a "universal IR" for source
6565 languages, it also provides a starting point for developing a "universal"
6566 atomic operation and synchronization IR.
6567</p>
6568<p>
6569 These do <em>not</em> form an API such as high-level threading libraries,
6570 software transaction memory systems, atomic primitives, and intrinsic
6571 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6572 application libraries. The hardware interface provided by LLVM should allow
6573 a clean implementation of all of these APIs and parallel programming models.
6574 No one model or paradigm should be selected above others unless the hardware
6575 itself ubiquitously does so.
6576
6577</p>
6578</div>
6579
6580<!-- _______________________________________________________________________ -->
6581<div class="doc_subsubsection">
6582 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6583</div>
6584<div class="doc_text">
6585<h5>Syntax:</h5>
6586<pre>
6587declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6588i1 &lt;device&gt; )
6589
6590</pre>
6591<h5>Overview:</h5>
6592<p>
6593 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6594 specific pairs of memory access types.
6595</p>
6596<h5>Arguments:</h5>
6597<p>
6598 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6599 The first four arguments enables a specific barrier as listed below. The fith
6600 argument specifies that the barrier applies to io or device or uncached memory.
6601
6602</p>
6603 <ul>
6604 <li><tt>ll</tt>: load-load barrier</li>
6605 <li><tt>ls</tt>: load-store barrier</li>
6606 <li><tt>sl</tt>: store-load barrier</li>
6607 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6608 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6609 </ul>
6610<h5>Semantics:</h5>
6611<p>
6612 This intrinsic causes the system to enforce some ordering constraints upon
6613 the loads and stores of the program. This barrier does not indicate
6614 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6615 which they occur. For any of the specified pairs of load and store operations
6616 (f.ex. load-load, or store-load), all of the first operations preceding the
6617 barrier will complete before any of the second operations succeeding the
6618 barrier begin. Specifically the semantics for each pairing is as follows:
6619</p>
6620 <ul>
6621 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6622 after the barrier begins.</li>
6623
6624 <li><tt>ls</tt>: All loads before the barrier must complete before any
6625 store after the barrier begins.</li>
6626 <li><tt>ss</tt>: All stores before the barrier must complete before any
6627 store after the barrier begins.</li>
6628 <li><tt>sl</tt>: All stores before the barrier must complete before any
6629 load after the barrier begins.</li>
6630 </ul>
6631<p>
6632 These semantics are applied with a logical "and" behavior when more than one
6633 is enabled in a single memory barrier intrinsic.
6634</p>
6635<p>
6636 Backends may implement stronger barriers than those requested when they do not
6637 support as fine grained a barrier as requested. Some architectures do not
6638 need all types of barriers and on such architectures, these become noops.
6639</p>
6640<h5>Example:</h5>
6641<pre>
6642%ptr = malloc i32
6643 store i32 4, %ptr
6644
6645%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6646 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6647 <i>; guarantee the above finishes</i>
6648 store i32 8, %ptr <i>; before this begins</i>
6649</pre>
6650</div>
6651
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6652<!-- _______________________________________________________________________ -->
6653<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6654 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6655</div>
6656<div class="doc_text">
6657<h5>Syntax:</h5>
6658<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6659 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6660 any integer bit width and for different address spaces. Not all targets
6661 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6662
6663<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6664declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6665declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6666declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6667declare 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]6668
6669</pre>
6670<h5>Overview:</h5>
6671<p>
6672 This loads a value in memory and compares it to a given value. If they are
6673 equal, it stores a new value into the memory.
6674</p>
6675<h5>Arguments:</h5>
6676<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6677 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6678 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6679 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6680 this integer type. While any bit width integer may be used, targets may only
6681 lower representations they support in hardware.
6682
6683</p>
6684<h5>Semantics:</h5>
6685<p>
6686 This entire intrinsic must be executed atomically. It first loads the value
6687 in memory pointed to by <tt>ptr</tt> and compares it with the value
6688 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6689 loaded value is yielded in all cases. This provides the equivalent of an
6690 atomic compare-and-swap operation within the SSA framework.
6691</p>
6692<h5>Examples:</h5>
6693
6694<pre>
6695%ptr = malloc i32
6696 store i32 4, %ptr
6697
6698%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6699%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6700 <i>; yields {i32}:result1 = 4</i>
6701%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6702%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6703
6704%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6705%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6706 <i>; yields {i32}:result2 = 8</i>
6707%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6708
6709%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6710</pre>
6711</div>
6712
6713<!-- _______________________________________________________________________ -->
6714<div class="doc_subsubsection">
6715 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6716</div>
6717<div class="doc_text">
6718<h5>Syntax:</h5>
6719
6720<p>
6721 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6722 integer bit width. Not all targets support all bit widths however.</p>
6723<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6724declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6725declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6726declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6727declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6728
6729</pre>
6730<h5>Overview:</h5>
6731<p>
6732 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6733 the value from memory. It then stores the value in <tt>val</tt> in the memory
6734 at <tt>ptr</tt>.
6735</p>
6736<h5>Arguments:</h5>
6737
6738<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6739 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6740 <tt>val</tt> argument and the result must be integers of the same bit width.
6741 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6742 integer type. The targets may only lower integer representations they
6743 support.
6744</p>
6745<h5>Semantics:</h5>
6746<p>
6747 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6748 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6749 equivalent of an atomic swap operation within the SSA framework.
6750
6751</p>
6752<h5>Examples:</h5>
6753<pre>
6754%ptr = malloc i32
6755 store i32 4, %ptr
6756
6757%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6758%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6759 <i>; yields {i32}:result1 = 4</i>
6760%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6761%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6762
6763%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6764%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6765 <i>; yields {i32}:result2 = 8</i>
6766
6767%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6768%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6769</pre>
6770</div>
6771
6772<!-- _______________________________________________________________________ -->
6773<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6774 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6775
6776</div>
6777<div class="doc_text">
6778<h5>Syntax:</h5>
6779<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6780 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]6781 integer bit width. Not all targets support all bit widths however.</p>
6782<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6783declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6784declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6785declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6786declare 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]6787
6788</pre>
6789<h5>Overview:</h5>
6790<p>
6791 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6792 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6793</p>
6794<h5>Arguments:</h5>
6795<p>
6796
6797 The intrinsic takes two arguments, the first a pointer to an integer value
6798 and the second an integer value. The result is also an integer value. These
6799 integer types can have any bit width, but they must all have the same bit
6800 width. The targets may only lower integer representations they support.
6801</p>
6802<h5>Semantics:</h5>
6803<p>
6804 This intrinsic does a series of operations atomically. It first loads the
6805 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6806 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6807</p>
6808
6809<h5>Examples:</h5>
6810<pre>
6811%ptr = malloc i32
6812 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6813%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6814 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6815%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6816 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6817%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6818 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6819%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6820</pre>
6821</div>
6822
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6823<!-- _______________________________________________________________________ -->
6824<div class="doc_subsubsection">
6825 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6826
6827</div>
6828<div class="doc_text">
6829<h5>Syntax:</h5>
6830<p>
6831 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]6832 any integer bit width and for different address spaces. Not all targets
6833 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6834<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6835declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6836declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6837declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6838declare 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]6839
6840</pre>
6841<h5>Overview:</h5>
6842<p>
6843 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6844 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6845</p>
6846<h5>Arguments:</h5>
6847<p>
6848
6849 The intrinsic takes two arguments, the first a pointer to an integer value
6850 and the second an integer value. The result is also an integer value. These
6851 integer types can have any bit width, but they must all have the same bit
6852 width. The targets may only lower integer representations they support.
6853</p>
6854<h5>Semantics:</h5>
6855<p>
6856 This intrinsic does a series of operations atomically. It first loads the
6857 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6858 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6859</p>
6860
6861<h5>Examples:</h5>
6862<pre>
6863%ptr = malloc i32
6864 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6865%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6866 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6867%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6868 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6869%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6870 <i>; yields {i32}:result3 = 2</i>
6871%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6872</pre>
6873</div>
6874
6875<!-- _______________________________________________________________________ -->
6876<div class="doc_subsubsection">
6877 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6878 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6879 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6880 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6881
6882</div>
6883<div class="doc_text">
6884<h5>Syntax:</h5>
6885<p>
6886 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6887 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6888 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6889 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6890<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6891declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6892declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6893declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6894declare 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]6895
6896</pre>
6897
6898<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6899declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6900declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6901declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6902declare 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]6903
6904</pre>
6905
6906<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6907declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6908declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6909declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6910declare 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]6911
6912</pre>
6913
6914<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6915declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6916declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6917declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6918declare 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]6919
6920</pre>
6921<h5>Overview:</h5>
6922<p>
6923 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6924 the value stored in memory at <tt>ptr</tt>. It yields the original value
6925 at <tt>ptr</tt>.
6926</p>
6927<h5>Arguments:</h5>
6928<p>
6929
6930 These intrinsics take two arguments, the first a pointer to an integer value
6931 and the second an integer value. The result is also an integer value. These
6932 integer types can have any bit width, but they must all have the same bit
6933 width. The targets may only lower integer representations they support.
6934</p>
6935<h5>Semantics:</h5>
6936<p>
6937 These intrinsics does a series of operations atomically. They first load the
6938 value stored at <tt>ptr</tt>. They then do the bitwise operation
6939 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6940 value stored at <tt>ptr</tt>.
6941</p>
6942
6943<h5>Examples:</h5>
6944<pre>
6945%ptr = malloc i32
6946 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6947%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6948 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6949%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6950 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6951%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6952 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6953%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6954 <i>; yields {i32}:result3 = FF</i>
6955%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6956</pre>
6957</div>
6958
6959
6960<!-- _______________________________________________________________________ -->
6961<div class="doc_subsubsection">
6962 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6963 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6964 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6965 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6966
6967</div>
6968<div class="doc_text">
6969<h5>Syntax:</h5>
6970<p>
6971 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6972 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6973 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6974 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6975 support all bit widths however.</p>
6976<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6977declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6978declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6979declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6980declare 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]6981
6982</pre>
6983
6984<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6985declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6986declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6987declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6988declare 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]6989
6990</pre>
6991
6992<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6993declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6994declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6995declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6996declare 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]6997
6998</pre>
6999
7000<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7001declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7002declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7003declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7004declare 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]7005
7006</pre>
7007<h5>Overview:</h5>
7008<p>
7009 These intrinsics takes the signed or unsigned minimum or maximum of
7010 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7011 original value at <tt>ptr</tt>.
7012</p>
7013<h5>Arguments:</h5>
7014<p>
7015
7016 These intrinsics take two arguments, the first a pointer to an integer value
7017 and the second an integer value. The result is also an integer value. These
7018 integer types can have any bit width, but they must all have the same bit
7019 width. The targets may only lower integer representations they support.
7020</p>
7021<h5>Semantics:</h5>
7022<p>
7023 These intrinsics does a series of operations atomically. They first load the
7024 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
7025 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
7026 the original value stored at <tt>ptr</tt>.
7027</p>
7028
7029<h5>Examples:</h5>
7030<pre>
7031%ptr = malloc i32
7032 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7033%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7034 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7035%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7036 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7037%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7038 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7039%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7040 <i>; yields {i32}:result3 = 8</i>
7041%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7042</pre>
7043</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7044
7045<!-- ======================================================================= -->
7046<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7047 <a name="int_general">General Intrinsics</a>
7048</div>
7049
7050<div class="doc_text">
7051<p> This class of intrinsics is designed to be generic and has
7052no specific purpose. </p>
7053</div>
7054
7055<!-- _______________________________________________________________________ -->
7056<div class="doc_subsubsection">
7057 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7058</div>
7059
7060<div class="doc_text">
7061
7062<h5>Syntax:</h5>
7063<pre>
7064 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7065</pre>
7066
7067<h5>Overview:</h5>
7068
7069<p>
7070The '<tt>llvm.var.annotation</tt>' intrinsic
7071</p>
7072
7073<h5>Arguments:</h5>
7074
7075<p>
7076The first argument is a pointer to a value, the second is a pointer to a
7077global string, the third is a pointer to a global string which is the source
7078file name, and the last argument is the line number.
7079</p>
7080
7081<h5>Semantics:</h5>
7082
7083<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7084This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7085This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7086annotations. These have no other defined use, they are ignored by code
7087generation and optimization.
7088</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7089</div>
7090
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7091<!-- _______________________________________________________________________ -->
7092<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7093 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7094</div>
7095
7096<div class="doc_text">
7097
7098<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7099<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7100any integer bit width.
7101</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7102<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7103 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7104 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7105 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7106 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7107 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]7108</pre>
7109
7110<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7111
7112<p>
7113The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7114</p>
7115
7116<h5>Arguments:</h5>
7117
7118<p>
7119The first argument is an integer value (result of some expression),
7120the second is a pointer to a global string, the third is a pointer to a global
7121string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7122It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7123</p>
7124
7125<h5>Semantics:</h5>
7126
7127<p>
7128This intrinsic allows annotations to be put on arbitrary expressions
7129with arbitrary strings. This can be useful for special purpose optimizations
7130that want to look for these annotations. These have no other defined use, they
7131are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]7132</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7133</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7134
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7135<!-- _______________________________________________________________________ -->
7136<div class="doc_subsubsection">
7137 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7138</div>
7139
7140<div class="doc_text">
7141
7142<h5>Syntax:</h5>
7143<pre>
7144 declare void @llvm.trap()
7145</pre>
7146
7147<h5>Overview:</h5>
7148
7149<p>
7150The '<tt>llvm.trap</tt>' intrinsic
7151</p>
7152
7153<h5>Arguments:</h5>
7154
7155<p>
7156None
7157</p>
7158
7159<h5>Semantics:</h5>
7160
7161<p>
7162This intrinsics is lowered to the target dependent trap instruction. If the
7163target does not have a trap instruction, this intrinsic will be lowered to the
7164call of the abort() function.
7165</p>
7166</div>
7167
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7168<!-- _______________________________________________________________________ -->
7169<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7170 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7171</div>
7172<div class="doc_text">
7173<h5>Syntax:</h5>
7174<pre>
7175declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
7176
7177</pre>
7178<h5>Overview:</h5>
7179<p>
7180 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
7181 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
7182 it is placed on the stack before local variables.
7183</p>
7184<h5>Arguments:</h5>
7185<p>
7186 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
7187 first argument is the value loaded from the stack guard
7188 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
7189 has enough space to hold the value of the guard.
7190</p>
7191<h5>Semantics:</h5>
7192<p>
7193 This intrinsic causes the prologue/epilogue inserter to force the position of
7194 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7195 stack. This is to ensure that if a local variable on the stack is overwritten,
7196 it will destroy the value of the guard. When the function exits, the guard on
7197 the stack is checked against the original guard. If they're different, then
7198 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
7199</p>
7200</div>
7201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7202<!-- *********************************************************************** -->
7203<hr>
7204<address>
7205 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7206 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7207 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7208 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]7209
7210 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7211 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7212 Last modified: $Date$
7213</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7215</body>
7216</html>