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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
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame^]1094<br><br>If a function that has an <tt>ssp</tt> attribute is inlined into a function
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1095that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame^]1096have an <tt>ssp</tt> attribute.</dd>
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]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
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame^]1103If a function that has an <tt>sspreq</tt> attribute is inlined into a
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1104function that doesn't have an <tt>sspreq</tt> attribute or which has
1105an <tt>ssp</tt> attribute, then the resulting function will have
Devang Patela2f9f412009-06-12 19:45:19 +0000[diff] [blame^]1106an <tt>sspreq</tt> attribute.</dd>
1107
1108<dt><tt>noredzone</tt></dt>
1109<dd>This attribute indicates that the code generator should not enforce red zone
1110mandated by target specific ABI.</dd>
1111
1112<dt><tt>noimplicitfloat</tt></dt>
1113<dd>This attributes disables implicit floating point instructions.</dd>
1114
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1115</dl>
1116
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1117</div>
1118
1119<!-- ======================================================================= -->
1120<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1121 <a name="moduleasm">Module-Level Inline Assembly</a>
1122</div>
1123
1124<div class="doc_text">
1125<p>
1126Modules may contain "module-level inline asm" blocks, which corresponds to the
1127GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1128LLVM and treated as a single unit, but may be separated in the .ll file if
1129desired. The syntax is very simple:
1130</p>
1131
1132<div class="doc_code">
1133<pre>
1134module asm "inline asm code goes here"
1135module asm "more can go here"
1136</pre>
1137</div>
1138
1139<p>The strings can contain any character by escaping non-printable characters.
1140 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1141 for the number.
1142</p>
1143
1144<p>
1145 The inline asm code is simply printed to the machine code .s file when
1146 assembly code is generated.
1147</p>
1148</div>
1149
1150<!-- ======================================================================= -->
1151<div class="doc_subsection">
1152 <a name="datalayout">Data Layout</a>
1153</div>
1154
1155<div class="doc_text">
1156<p>A module may specify a target specific data layout string that specifies how
1157data is to be laid out in memory. The syntax for the data layout is simply:</p>
1158<pre> target datalayout = "<i>layout specification</i>"</pre>
1159<p>The <i>layout specification</i> consists of a list of specifications
1160separated by the minus sign character ('-'). Each specification starts with a
1161letter and may include other information after the letter to define some
1162aspect of the data layout. The specifications accepted are as follows: </p>
1163<dl>
1164 <dt><tt>E</tt></dt>
1165 <dd>Specifies that the target lays out data in big-endian form. That is, the
1166 bits with the most significance have the lowest address location.</dd>
1167 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1168 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1169 the bits with the least significance have the lowest address location.</dd>
1170 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1171 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1172 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1173 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1174 too.</dd>
1175 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1176 <dd>This specifies the alignment for an integer type of a given bit
1177 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1178 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1179 <dd>This specifies the alignment for a vector type of a given bit
1180 <i>size</i>.</dd>
1181 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1182 <dd>This specifies the alignment for a floating point type of a given bit
1183 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1184 (double).</dd>
1185 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1186 <dd>This specifies the alignment for an aggregate type of a given bit
1187 <i>size</i>.</dd>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1188 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1189 <dd>This specifies the alignment for a stack object of a given bit
1190 <i>size</i>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1191</dl>
1192<p>When constructing the data layout for a given target, LLVM starts with a
1193default set of specifications which are then (possibly) overriden by the
1194specifications in the <tt>datalayout</tt> keyword. The default specifications
1195are given in this list:</p>
1196<ul>
1197 <li><tt>E</tt> - big endian</li>
1198 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1199 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1200 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1201 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1202 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1203 <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]1204 alignment of 64-bits</li>
1205 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1206 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1207 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1208 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1209 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbard88a97b2009-06-08 22:17:53 +0000[diff] [blame]1210 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1211</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1212<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1213following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1214<ol>
1215 <li>If the type sought is an exact match for one of the specifications, that
1216 specification is used.</li>
1217 <li>If no match is found, and the type sought is an integer type, then the
1218 smallest integer type that is larger than the bitwidth of the sought type is
1219 used. If none of the specifications are larger than the bitwidth then the the
1220 largest integer type is used. For example, given the default specifications
1221 above, the i7 type will use the alignment of i8 (next largest) while both
1222 i65 and i256 will use the alignment of i64 (largest specified).</li>
1223 <li>If no match is found, and the type sought is a vector type, then the
1224 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1225 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1226 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1227</ol>
1228</div>
1229
1230<!-- *********************************************************************** -->
1231<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1232<!-- *********************************************************************** -->
1233
1234<div class="doc_text">
1235
1236<p>The LLVM type system is one of the most important features of the
1237intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1238optimizations to be performed on the intermediate representation directly,
1239without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1240extra analyses on the side before the transformation. A strong type
1241system makes it easier to read the generated code and enables novel
1242analyses and transformations that are not feasible to perform on normal
1243three address code representations.</p>
1244
1245</div>
1246
1247<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1248<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1249Classifications</a> </div>
1250<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1251<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1252classifications:</p>
1253
1254<table border="1" cellspacing="0" cellpadding="4">
1255 <tbody>
1256 <tr><th>Classification</th><th>Types</th></tr>
1257 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1258 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1260 </tr>
1261 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1262 <td><a href="#t_floating">floating point</a></td>
1263 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1264 </tr>
1265 <tr>
1266 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1267 <td><a href="#t_integer">integer</a>,
1268 <a href="#t_floating">floating point</a>,
1269 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1270 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1271 <a href="#t_struct">structure</a>,
1272 <a href="#t_array">array</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1273 <a href="#t_label">label</a>,
1274 <a href="#t_metadata">metadata</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1275 </td>
1276 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1277 <tr>
1278 <td><a href="#t_primitive">primitive</a></td>
1279 <td><a href="#t_label">label</a>,
1280 <a href="#t_void">void</a>,
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1281 <a href="#t_floating">floating point</a>,
1282 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1283 </tr>
1284 <tr>
1285 <td><a href="#t_derived">derived</a></td>
1286 <td><a href="#t_integer">integer</a>,
1287 <a href="#t_array">array</a>,
1288 <a href="#t_function">function</a>,
1289 <a href="#t_pointer">pointer</a>,
1290 <a href="#t_struct">structure</a>,
1291 <a href="#t_pstruct">packed structure</a>,
1292 <a href="#t_vector">vector</a>,
1293 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1294 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1295 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1296 </tbody>
1297</table>
1298
1299<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1300most important. Values of these types are the only ones which can be
1301produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1302instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1303</div>
1304
1305<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1306<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1307
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1308<div class="doc_text">
1309<p>The primitive types are the fundamental building blocks of the LLVM
1310system.</p>
1311
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1312</div>
1313
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1314<!-- _______________________________________________________________________ -->
1315<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1316
1317<div class="doc_text">
1318 <table>
1319 <tbody>
1320 <tr><th>Type</th><th>Description</th></tr>
1321 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1322 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1323 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1324 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1325 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1326 </tbody>
1327 </table>
1328</div>
1329
1330<!-- _______________________________________________________________________ -->
1331<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1332
1333<div class="doc_text">
1334<h5>Overview:</h5>
1335<p>The void type does not represent any value and has no size.</p>
1336
1337<h5>Syntax:</h5>
1338
1339<pre>
1340 void
1341</pre>
1342</div>
1343
1344<!-- _______________________________________________________________________ -->
1345<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1346
1347<div class="doc_text">
1348<h5>Overview:</h5>
1349<p>The label type represents code labels.</p>
1350
1351<h5>Syntax:</h5>
1352
1353<pre>
1354 label
1355</pre>
1356</div>
1357
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]1358<!-- _______________________________________________________________________ -->
1359<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
1360
1361<div class="doc_text">
1362<h5>Overview:</h5>
1363<p>The metadata type represents embedded metadata. The only derived type that
1364may contain metadata is <tt>metadata*</tt> or a function type that returns or
1365takes metadata typed parameters, but not pointer to metadata types.</p>
1366
1367<h5>Syntax:</h5>
1368
1369<pre>
1370 metadata
1371</pre>
1372</div>
1373
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1374
1375<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1376<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1377
1378<div class="doc_text">
1379
1380<p>The real power in LLVM comes from the derived types in the system.
1381This is what allows a programmer to represent arrays, functions,
1382pointers, and other useful types. Note that these derived types may be
1383recursive: For example, it is possible to have a two dimensional array.</p>
1384
1385</div>
1386
1387<!-- _______________________________________________________________________ -->
1388<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1389
1390<div class="doc_text">
1391
1392<h5>Overview:</h5>
1393<p>The integer type is a very simple derived type that simply specifies an
1394arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13952^23-1 (about 8 million) can be specified.</p>
1396
1397<h5>Syntax:</h5>
1398
1399<pre>
1400 iN
1401</pre>
1402
1403<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1404value.</p>
1405
1406<h5>Examples:</h5>
1407<table class="layout">
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1408 <tr class="layout">
1409 <td class="left"><tt>i1</tt></td>
1410 <td class="left">a single-bit integer.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1411 </tr>
Nick Lewycky39382d62009-05-24 02:46:06 +0000[diff] [blame]1412 <tr class="layout">
1413 <td class="left"><tt>i32</tt></td>
1414 <td class="left">a 32-bit integer.</td>
1415 </tr>
1416 <tr class="layout">
1417 <td class="left"><tt>i1942652</tt></td>
1418 <td class="left">a really big integer of over 1 million bits.</td>
1419 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1420</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1421
1422<p>Note that the code generator does not yet support large integer types
1423to be used as function return types. The specific limit on how large a
1424return type the code generator can currently handle is target-dependent;
1425currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1426targets.</p>
1427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1428</div>
1429
1430<!-- _______________________________________________________________________ -->
1431<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1432
1433<div class="doc_text">
1434
1435<h5>Overview:</h5>
1436
1437<p>The array type is a very simple derived type that arranges elements
1438sequentially in memory. The array type requires a size (number of
1439elements) and an underlying data type.</p>
1440
1441<h5>Syntax:</h5>
1442
1443<pre>
1444 [&lt;# elements&gt; x &lt;elementtype&gt;]
1445</pre>
1446
1447<p>The number of elements is a constant integer value; elementtype may
1448be any type with a size.</p>
1449
1450<h5>Examples:</h5>
1451<table class="layout">
1452 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1453 <td class="left"><tt>[40 x i32]</tt></td>
1454 <td class="left">Array of 40 32-bit integer values.</td>
1455 </tr>
1456 <tr class="layout">
1457 <td class="left"><tt>[41 x i32]</tt></td>
1458 <td class="left">Array of 41 32-bit integer values.</td>
1459 </tr>
1460 <tr class="layout">
1461 <td class="left"><tt>[4 x i8]</tt></td>
1462 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1463 </tr>
1464</table>
1465<p>Here are some examples of multidimensional arrays:</p>
1466<table class="layout">
1467 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1468 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1469 <td class="left">3x4 array of 32-bit integer values.</td>
1470 </tr>
1471 <tr class="layout">
1472 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1473 <td class="left">12x10 array of single precision floating point values.</td>
1474 </tr>
1475 <tr class="layout">
1476 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1477 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1478 </tr>
1479</table>
1480
1481<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1482length array. Normally, accesses past the end of an array are undefined in
1483LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1484As a special case, however, zero length arrays are recognized to be variable
1485length. This allows implementation of 'pascal style arrays' with the LLVM
1486type "{ i32, [0 x float]}", for example.</p>
1487
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1488<p>Note that the code generator does not yet support large aggregate types
1489to be used as function return types. The specific limit on how large an
1490aggregate return type the code generator can currently handle is
1491target-dependent, and also dependent on the aggregate element types.</p>
1492
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1493</div>
1494
1495<!-- _______________________________________________________________________ -->
1496<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1497<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1498
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1499<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1501<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1502consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1503return 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]1504If 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]1505class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1507<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1508
1509<pre>
1510 &lt;returntype list&gt; (&lt;parameter list&gt;)
1511</pre>
1512
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1513<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1514specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1515which indicates that the function takes a variable number of arguments.
1516Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1517 href="#int_varargs">variable argument handling intrinsic</a> functions.
1518'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1519<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1520
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1521<h5>Examples:</h5>
1522<table class="layout">
1523 <tr class="layout">
1524 <td class="left"><tt>i32 (i32)</tt></td>
1525 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1526 </td>
1527 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1528 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1529 </tt></td>
1530 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1531 an <tt>i16</tt> that should be sign extended and a
1532 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1533 <tt>float</tt>.
1534 </td>
1535 </tr><tr class="layout">
1536 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1537 <td class="left">A vararg function that takes at least one
1538 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1539 which returns an integer. This is the signature for <tt>printf</tt> in
1540 LLVM.
1541 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1542 </tr><tr class="layout">
1543 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1544 <td class="left">A function taking an <tt>i32</tt>, returning two
1545 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1546 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1547 </tr>
1548</table>
1549
1550</div>
1551<!-- _______________________________________________________________________ -->
1552<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1553<div class="doc_text">
1554<h5>Overview:</h5>
1555<p>The structure type is used to represent a collection of data members
1556together in memory. The packing of the field types is defined to match
1557the ABI of the underlying processor. The elements of a structure may
1558be any type that has a size.</p>
1559<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1560and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1561field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1562instruction.</p>
1563<h5>Syntax:</h5>
1564<pre> { &lt;type list&gt; }<br></pre>
1565<h5>Examples:</h5>
1566<table class="layout">
1567 <tr class="layout">
1568 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1569 <td class="left">A triple of three <tt>i32</tt> values</td>
1570 </tr><tr class="layout">
1571 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1572 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1573 second element is a <a href="#t_pointer">pointer</a> to a
1574 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1575 an <tt>i32</tt>.</td>
1576 </tr>
1577</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1578
1579<p>Note that the code generator does not yet support large aggregate types
1580to be used as function return types. The specific limit on how large an
1581aggregate return type the code generator can currently handle is
1582target-dependent, and also dependent on the aggregate element types.</p>
1583
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1584</div>
1585
1586<!-- _______________________________________________________________________ -->
1587<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1588</div>
1589<div class="doc_text">
1590<h5>Overview:</h5>
1591<p>The packed structure type is used to represent a collection of data members
1592together in memory. There is no padding between fields. Further, the alignment
1593of a packed structure is 1 byte. The elements of a packed structure may
1594be any type that has a size.</p>
1595<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1596and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1597field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1598instruction.</p>
1599<h5>Syntax:</h5>
1600<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1601<h5>Examples:</h5>
1602<table class="layout">
1603 <tr class="layout">
1604 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1605 <td class="left">A triple of three <tt>i32</tt> values</td>
1606 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1607 <td class="left">
1608<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1609 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1610 second element is a <a href="#t_pointer">pointer</a> to a
1611 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1612 an <tt>i32</tt>.</td>
1613 </tr>
1614</table>
1615</div>
1616
1617<!-- _______________________________________________________________________ -->
1618<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1619<div class="doc_text">
1620<h5>Overview:</h5>
1621<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1622reference to another object, which must live in memory. Pointer types may have
1623an optional address space attribute defining the target-specific numbered
1624address space where the pointed-to object resides. The default address space is
1625zero.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1626
1627<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]1628it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner96edbd32009-02-08 19:53:29 +0000[diff] [blame]1629
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1630<h5>Syntax:</h5>
1631<pre> &lt;type&gt; *<br></pre>
1632<h5>Examples:</h5>
1633<table class="layout">
1634 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]1635 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1636 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1637 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1638 </tr>
1639 <tr class="layout">
1640 <td class="left"><tt>i32 (i32 *) *</tt></td>
1641 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1642 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1643 <tt>i32</tt>.</td>
1644 </tr>
1645 <tr class="layout">
1646 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1647 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1648 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1649 </tr>
1650</table>
1651</div>
1652
1653<!-- _______________________________________________________________________ -->
1654<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1655<div class="doc_text">
1656
1657<h5>Overview:</h5>
1658
1659<p>A vector type is a simple derived type that represents a vector
1660of elements. Vector types are used when multiple primitive data
1661are operated in parallel using a single instruction (SIMD).
1662A vector type requires a size (number of
1663elements) and an underlying primitive data type. Vectors must have a power
1664of two length (1, 2, 4, 8, 16 ...). Vector types are
1665considered <a href="#t_firstclass">first class</a>.</p>
1666
1667<h5>Syntax:</h5>
1668
1669<pre>
1670 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1671</pre>
1672
1673<p>The number of elements is a constant integer value; elementtype may
1674be any integer or floating point type.</p>
1675
1676<h5>Examples:</h5>
1677
1678<table class="layout">
1679 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1680 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1681 <td class="left">Vector of 4 32-bit integer values.</td>
1682 </tr>
1683 <tr class="layout">
1684 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1685 <td class="left">Vector of 8 32-bit floating-point values.</td>
1686 </tr>
1687 <tr class="layout">
1688 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1689 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1690 </tr>
1691</table>
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]1692
1693<p>Note that the code generator does not yet support large vector types
1694to be used as function return types. The specific limit on how large a
1695vector return type codegen can currently handle is target-dependent;
1696currently it's often a few times longer than a hardware vector register.</p>
1697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1698</div>
1699
1700<!-- _______________________________________________________________________ -->
1701<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1702<div class="doc_text">
1703
1704<h5>Overview:</h5>
1705
1706<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1707corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1708In LLVM, opaque types can eventually be resolved to any type (not just a
1709structure type).</p>
1710
1711<h5>Syntax:</h5>
1712
1713<pre>
1714 opaque
1715</pre>
1716
1717<h5>Examples:</h5>
1718
1719<table class="layout">
1720 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1721 <td class="left"><tt>opaque</tt></td>
1722 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1723 </tr>
1724</table>
1725</div>
1726
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1727<!-- ======================================================================= -->
1728<div class="doc_subsection">
1729 <a name="t_uprefs">Type Up-references</a>
1730</div>
1731
1732<div class="doc_text">
1733<h5>Overview:</h5>
1734<p>
1735An "up reference" allows you to refer to a lexically enclosing type without
1736requiring it to have a name. For instance, a structure declaration may contain a
1737pointer to any of the types it is lexically a member of. Example of up
1738references (with their equivalent as named type declarations) include:</p>
1739
1740<pre>
Chris Lattner5ad632d2009-02-09 10:00:56 +0000[diff] [blame]1741 { \2 * } %x = type { %x* }
Chris Lattner515195a2009-02-02 07:32:36 +0000[diff] [blame]1742 { \2 }* %y = type { %y }*
1743 \1* %z = type %z*
1744</pre>
1745
1746<p>
1747An up reference is needed by the asmprinter for printing out cyclic types when
1748there is no declared name for a type in the cycle. Because the asmprinter does
1749not want to print out an infinite type string, it needs a syntax to handle
1750recursive types that have no names (all names are optional in llvm IR).
1751</p>
1752
1753<h5>Syntax:</h5>
1754<pre>
1755 \&lt;level&gt;
1756</pre>
1757
1758<p>
1759The level is the count of the lexical type that is being referred to.
1760</p>
1761
1762<h5>Examples:</h5>
1763
1764<table class="layout">
1765 <tr class="layout">
1766 <td class="left"><tt>\1*</tt></td>
1767 <td class="left">Self-referential pointer.</td>
1768 </tr>
1769 <tr class="layout">
1770 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1771 <td class="left">Recursive structure where the upref refers to the out-most
1772 structure.</td>
1773 </tr>
1774</table>
1775</div>
1776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1777
1778<!-- *********************************************************************** -->
1779<div class="doc_section"> <a name="constants">Constants</a> </div>
1780<!-- *********************************************************************** -->
1781
1782<div class="doc_text">
1783
1784<p>LLVM has several different basic types of constants. This section describes
1785them all and their syntax.</p>
1786
1787</div>
1788
1789<!-- ======================================================================= -->
1790<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1791
1792<div class="doc_text">
1793
1794<dl>
1795 <dt><b>Boolean constants</b></dt>
1796
1797 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1798 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1799 </dd>
1800
1801 <dt><b>Integer constants</b></dt>
1802
1803 <dd>Standard integers (such as '4') are constants of the <a
1804 href="#t_integer">integer</a> type. Negative numbers may be used with
1805 integer types.
1806 </dd>
1807
1808 <dt><b>Floating point constants</b></dt>
1809
1810 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1811 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1812 notation (see below). The assembler requires the exact decimal value of
1813 a floating-point constant. For example, the assembler accepts 1.25 but
1814 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1815 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1816
1817 <dt><b>Null pointer constants</b></dt>
1818
1819 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1820 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1821
1822</dl>
1823
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1824<p>The one non-intuitive notation for constants is the hexadecimal form
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1825of floating point constants. For example, the form '<tt>double
18260x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
18274.5e+15</tt>'. The only time hexadecimal floating point constants are required
1828(and the only time that they are generated by the disassembler) is when a
1829floating point constant must be emitted but it cannot be represented as a
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1830decimal floating point number in a reasonable number of digits. For example,
1831NaN's, infinities, and other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1832special values are represented in their IEEE hexadecimal format so that
1833assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesenf82a52f2009-02-11 22:14:51 +0000[diff] [blame]1834<p>When using the hexadecimal form, constants of types float and double are
1835represented using the 16-digit form shown above (which matches the IEEE754
1836representation for double); float values must, however, be exactly representable
1837as IEE754 single precision.
1838Hexadecimal format is always used for long
1839double, and there are three forms of long double. The 80-bit
1840format used by x86 is represented as <tt>0xK</tt>
1841followed by 20 hexadecimal digits.
1842The 128-bit format used by PowerPC (two adjacent doubles) is represented
1843by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1844format is represented
1845by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1846target uses this format. Long doubles will only work if they match
1847the long double format on your target. All hexadecimal formats are big-endian
1848(sign bit at the left).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1849</div>
1850
1851<!-- ======================================================================= -->
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1852<div class="doc_subsection">
1853<a name="aggregateconstants"> <!-- old anchor -->
1854<a name="complexconstants">Complex Constants</a></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1855</div>
1856
1857<div class="doc_text">
Chris Lattner97063852009-02-28 18:32:25 +0000[diff] [blame]1858<p>Complex constants are a (potentially recursive) combination of simple
1859constants and smaller complex constants.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1860
1861<dl>
1862 <dt><b>Structure constants</b></dt>
1863
1864 <dd>Structure constants are represented with notation similar to structure
1865 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1866 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1867 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]1868 must have <a href="#t_struct">structure type</a>, and the number and
1869 types of elements must match those specified by the type.
1870 </dd>
1871
1872 <dt><b>Array constants</b></dt>
1873
1874 <dd>Array constants are represented with notation similar to array type
1875 definitions (a comma separated list of elements, surrounded by square brackets
1876 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1877 constants must have <a href="#t_array">array type</a>, and the number and
1878 types of elements must match those specified by the type.
1879 </dd>
1880
1881 <dt><b>Vector constants</b></dt>
1882
1883 <dd>Vector constants are represented with notation similar to vector type
1884 definitions (a comma separated list of elements, surrounded by
1885 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1886 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1887 href="#t_vector">vector type</a>, and the number and types of elements must
1888 match those specified by the type.
1889 </dd>
1890
1891 <dt><b>Zero initialization</b></dt>
1892
1893 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1894 value to zero of <em>any</em> type, including scalar and aggregate types.
1895 This is often used to avoid having to print large zero initializers (e.g. for
1896 large arrays) and is always exactly equivalent to using explicit zero
1897 initializers.
1898 </dd>
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1899
1900 <dt><b>Metadata node</b></dt>
1901
Nick Lewyckyf122c7e2009-05-30 16:08:30 +0000[diff] [blame]1902 <dd>A metadata node is a structure-like constant with
1903 <a href="#t_metadata">metadata type</a>. For example:
1904 "<tt>metadata !{ i32 0, metadata !"test" }</tt>". Unlike other constants
1905 that are meant to be interpreted as part of the instruction stream, metadata
1906 is a place to attach additional information such as debug info.
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]1907 </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1908</dl>
1909
1910</div>
1911
1912<!-- ======================================================================= -->
1913<div class="doc_subsection">
1914 <a name="globalconstants">Global Variable and Function Addresses</a>
1915</div>
1916
1917<div class="doc_text">
1918
1919<p>The addresses of <a href="#globalvars">global variables</a> and <a
1920href="#functionstructure">functions</a> are always implicitly valid (link-time)
1921constants. These constants are explicitly referenced when the <a
1922href="#identifiers">identifier for the global</a> is used and always have <a
1923href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1924file:</p>
1925
1926<div class="doc_code">
1927<pre>
1928@X = global i32 17
1929@Y = global i32 42
1930@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1931</pre>
1932</div>
1933
1934</div>
1935
1936<!-- ======================================================================= -->
1937<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1938<div class="doc_text">
1939 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1940 no specific value. Undefined values may be of any type and be used anywhere
1941 a constant is permitted.</p>
1942
1943 <p>Undefined values indicate to the compiler that the program is well defined
1944 no matter what value is used, giving the compiler more freedom to optimize.
1945 </p>
1946</div>
1947
1948<!-- ======================================================================= -->
1949<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1950</div>
1951
1952<div class="doc_text">
1953
1954<p>Constant expressions are used to allow expressions involving other constants
1955to be used as constants. Constant expressions may be of any <a
1956href="#t_firstclass">first class</a> type and may involve any LLVM operation
1957that does not have side effects (e.g. load and call are not supported). The
1958following is the syntax for constant expressions:</p>
1959
1960<dl>
1961 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1962 <dd>Truncate a constant to another type. The bit size of CST must be larger
1963 than the bit size of TYPE. Both types must be integers.</dd>
1964
1965 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1966 <dd>Zero extend a constant to another type. The bit size of CST must be
1967 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1968
1969 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1970 <dd>Sign extend a constant to another type. The bit size of CST must be
1971 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1972
1973 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1974 <dd>Truncate a floating point constant to another floating point type. The
1975 size of CST must be larger than the size of TYPE. Both types must be
1976 floating point.</dd>
1977
1978 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1979 <dd>Floating point extend a constant to another type. The size of CST must be
1980 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1981
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1982 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1984 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1985 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1986 of the same number of elements. If the value won't fit in the integer type,
1987 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988
1989 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1990 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1991 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1992 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1993 of the same number of elements. If the value won't fit in the integer type,
1994 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1995
1996 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1997 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1998 constant. TYPE must be a scalar or vector floating point type. CST must be of
1999 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
2000 of the same number of elements. If the value won't fit in the floating point
2001 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2002
2003 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
2004 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]2005 constant. TYPE must be a scalar or vector floating point type. CST must be of
2006 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
2007 of the same number of elements. If the value won't fit in the floating point
2008 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2009
2010 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
2011 <dd>Convert a pointer typed constant to the corresponding integer constant
2012 TYPE must be an integer type. CST must be of pointer type. The CST value is
2013 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
2014
2015 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
2016 <dd>Convert a integer constant to a pointer constant. TYPE must be a
2017 pointer type. CST must be of integer type. The CST value is zero extended,
2018 truncated, or unchanged to make it fit in a pointer size. This one is
2019 <i>really</i> dangerous!</dd>
2020
2021 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner557bc5d2009-02-28 18:27:03 +0000[diff] [blame]2022 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2023 are the same as those for the <a href="#i_bitcast">bitcast
2024 instruction</a>.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2025
2026 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
2027
2028 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
2029 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2030 instruction, the index list may have zero or more indexes, which are required
2031 to make sense for the type of "CSTPTR".</dd>
2032
2033 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
2034
2035 <dd>Perform the <a href="#i_select">select operation</a> on
2036 constants.</dd>
2037
2038 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2039 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2040
2041 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2042 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
2043
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]2044 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
2045 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
2046
2047 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
2048 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
2049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2050 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2051
2052 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2053 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2054
2055 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2056
2057 <dd>Perform the <a href="#i_insertelement">insertelement
2058 operation</a> on constants.</dd>
2059
2060
2061 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2062
2063 <dd>Perform the <a href="#i_shufflevector">shufflevector
2064 operation</a> on constants.</dd>
2065
2066 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2067
2068 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2069 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
2070 binary</a> operations. The constraints on operands are the same as those for
2071 the corresponding instruction (e.g. no bitwise operations on floating point
2072 values are allowed).</dd>
2073</dl>
2074</div>
2075
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2076<!-- ======================================================================= -->
2077<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2078</div>
2079
2080<div class="doc_text">
2081
2082<p>Embedded metadata provides a way to attach arbitrary data to the
2083instruction stream without affecting the behaviour of the program. There are
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2084two metadata primitives, strings and nodes. All metadata has the
2085<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
2086point ('<tt>!</tt>').
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2087</p>
2088
2089<p>A metadata string is a string surrounded by double quotes. It can contain
2090any character by escaping non-printable characters with "\xx" where "xx" is
2091the two digit hex code. For example: "<tt>!"test\00"</tt>".
2092</p>
2093
2094<p>Metadata nodes are represented with notation similar to structure constants
2095(a comma separated list of elements, surrounded by braces and preceeded by an
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2096exclamation point). For example: "<tt>!{ metadata !"test\00", i32 10}</tt>".
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2097</p>
2098
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2099<p>A metadata node will attempt to track changes to the values it holds. In
2100the event that a value is deleted, it will be replaced with a typeless
Nick Lewycky29aaef82009-05-30 05:06:04 +0000[diff] [blame]2101"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky117f4382009-05-10 20:57:05 +0000[diff] [blame]2102
Nick Lewycky4dcf8102009-04-04 07:22:01 +0000[diff] [blame]2103<p>Optimizations may rely on metadata to provide additional information about
2104the program that isn't available in the instructions, or that isn't easily
2105computable. Similarly, the code generator may expect a certain metadata format
2106to be used to express debugging information.</p>
2107</div>
2108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2109<!-- *********************************************************************** -->
2110<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2111<!-- *********************************************************************** -->
2112
2113<!-- ======================================================================= -->
2114<div class="doc_subsection">
2115<a name="inlineasm">Inline Assembler Expressions</a>
2116</div>
2117
2118<div class="doc_text">
2119
2120<p>
2121LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2122Module-Level Inline Assembly</a>) through the use of a special value. This
2123value represents the inline assembler as a string (containing the instructions
2124to emit), a list of operand constraints (stored as a string), and a flag that
2125indicates whether or not the inline asm expression has side effects. An example
2126inline assembler expression is:
2127</p>
2128
2129<div class="doc_code">
2130<pre>
2131i32 (i32) asm "bswap $0", "=r,r"
2132</pre>
2133</div>
2134
2135<p>
2136Inline assembler expressions may <b>only</b> be used as the callee operand of
2137a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2138</p>
2139
2140<div class="doc_code">
2141<pre>
2142%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
2143</pre>
2144</div>
2145
2146<p>
2147Inline asms with side effects not visible in the constraint list must be marked
2148as having side effects. This is done through the use of the
2149'<tt>sideeffect</tt>' keyword, like so:
2150</p>
2151
2152<div class="doc_code">
2153<pre>
2154call void asm sideeffect "eieio", ""()
2155</pre>
2156</div>
2157
2158<p>TODO: The format of the asm and constraints string still need to be
2159documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]2160need to be documented). This is probably best done by reference to another
2161document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162</p>
2163
2164</div>
2165
2166<!-- *********************************************************************** -->
2167<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2168<!-- *********************************************************************** -->
2169
2170<div class="doc_text">
2171
2172<p>The LLVM instruction set consists of several different
2173classifications of instructions: <a href="#terminators">terminator
2174instructions</a>, <a href="#binaryops">binary instructions</a>,
2175<a href="#bitwiseops">bitwise binary instructions</a>, <a
2176 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2177instructions</a>.</p>
2178
2179</div>
2180
2181<!-- ======================================================================= -->
2182<div class="doc_subsection"> <a name="terminators">Terminator
2183Instructions</a> </div>
2184
2185<div class="doc_text">
2186
2187<p>As mentioned <a href="#functionstructure">previously</a>, every
2188basic block in a program ends with a "Terminator" instruction, which
2189indicates which block should be executed after the current block is
2190finished. These terminator instructions typically yield a '<tt>void</tt>'
2191value: they produce control flow, not values (the one exception being
2192the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
2193<p>There are six different terminator instructions: the '<a
2194 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2195instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
2196the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2197 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2198 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
2199
2200</div>
2201
2202<!-- _______________________________________________________________________ -->
2203<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2204Instruction</a> </div>
2205<div class="doc_text">
2206<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2207<pre>
2208 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]2209 ret void <i>; Return from void function</i>
2210</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2211
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2212<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2213
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2214<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2215optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2216<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2217returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2218control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2219
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2220<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2221
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]2222<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2223the return value. The type of the return value must be a
2224'<a href="#t_firstclass">first class</a>' type.</p>
2225
2226<p>A function is not <a href="#wellformed">well formed</a> if
2227it it has a non-void return type and contains a '<tt>ret</tt>'
2228instruction with no return value or a return value with a type that
2229does not match its type, or if it has a void return type and contains
2230a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2232<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2234<p>When the '<tt>ret</tt>' instruction is executed, control flow
2235returns back to the calling function's context. If the caller is a "<a
2236 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
2237the instruction after the call. If the caller was an "<a
2238 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
2239at the beginning of the "normal" destination block. If the instruction
2240returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2241return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2243<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]2244
2245<pre>
2246 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2247 ret void <i>; Return from a void function</i>
Bill Wendlingd163e2d2009-02-28 22:12:54 +0000[diff] [blame]2248 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]2249</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2250
djge93155c2009-01-24 15:58:40 +0000[diff] [blame]2251<p>Note that the code generator does not yet fully support large
2252 return values. The specific sizes that are currently supported are
2253 dependent on the target. For integers, on 32-bit targets the limit
2254 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2255 For aggregate types, the current limits are dependent on the element
2256 types; for example targets are often limited to 2 total integer
2257 elements and 2 total floating-point elements.</p>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]2258
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2259</div>
2260<!-- _______________________________________________________________________ -->
2261<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2262<div class="doc_text">
2263<h5>Syntax:</h5>
2264<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2265</pre>
2266<h5>Overview:</h5>
2267<p>The '<tt>br</tt>' instruction is used to cause control flow to
2268transfer to a different basic block in the current function. There are
2269two forms of this instruction, corresponding to a conditional branch
2270and an unconditional branch.</p>
2271<h5>Arguments:</h5>
2272<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2273single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2274unconditional form of the '<tt>br</tt>' instruction takes a single
2275'<tt>label</tt>' value as a target.</p>
2276<h5>Semantics:</h5>
2277<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2278argument is evaluated. If the value is <tt>true</tt>, control flows
2279to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2280control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2281<h5>Example:</h5>
Chris Lattner95127832009-05-09 18:11:50 +0000[diff] [blame]2282<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]2283 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2284</div>
2285<!-- _______________________________________________________________________ -->
2286<div class="doc_subsubsection">
2287 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2288</div>
2289
2290<div class="doc_text">
2291<h5>Syntax:</h5>
2292
2293<pre>
2294 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2295</pre>
2296
2297<h5>Overview:</h5>
2298
2299<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2300several different places. It is a generalization of the '<tt>br</tt>'
2301instruction, allowing a branch to occur to one of many possible
2302destinations.</p>
2303
2304
2305<h5>Arguments:</h5>
2306
2307<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2308comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2309an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2310table is not allowed to contain duplicate constant entries.</p>
2311
2312<h5>Semantics:</h5>
2313
2314<p>The <tt>switch</tt> instruction specifies a table of values and
2315destinations. When the '<tt>switch</tt>' instruction is executed, this
2316table is searched for the given value. If the value is found, control flow is
2317transfered to the corresponding destination; otherwise, control flow is
2318transfered to the default destination.</p>
2319
2320<h5>Implementation:</h5>
2321
2322<p>Depending on properties of the target machine and the particular
2323<tt>switch</tt> instruction, this instruction may be code generated in different
2324ways. For example, it could be generated as a series of chained conditional
2325branches or with a lookup table.</p>
2326
2327<h5>Example:</h5>
2328
2329<pre>
2330 <i>; Emulate a conditional br instruction</i>
2331 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2332 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2333
2334 <i>; Emulate an unconditional br instruction</i>
2335 switch i32 0, label %dest [ ]
2336
2337 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame]2338 switch i32 %val, label %otherwise [ i32 0, label %onzero
2339 i32 1, label %onone
2340 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2341</pre>
2342</div>
2343
2344<!-- _______________________________________________________________________ -->
2345<div class="doc_subsubsection">
2346 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2347</div>
2348
2349<div class="doc_text">
2350
2351<h5>Syntax:</h5>
2352
2353<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2354 &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]2355 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2356</pre>
2357
2358<h5>Overview:</h5>
2359
2360<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2361function, with the possibility of control flow transfer to either the
2362'<tt>normal</tt>' label or the
2363'<tt>exception</tt>' label. If the callee function returns with the
2364"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2365"normal" label. If the callee (or any indirect callees) returns with the "<a
2366href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2367continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2368
2369<h5>Arguments:</h5>
2370
2371<p>This instruction requires several arguments:</p>
2372
2373<ol>
2374 <li>
2375 The optional "cconv" marker indicates which <a href="#callingconv">calling
2376 convention</a> the call should use. If none is specified, the call defaults
2377 to using C calling conventions.
2378 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2379
2380 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2381 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2382 and '<tt>inreg</tt>' attributes are valid here.</li>
2383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2384 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2385 function value being invoked. In most cases, this is a direct function
2386 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2387 an arbitrary pointer to function value.
2388 </li>
2389
2390 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2391 function to be invoked. </li>
2392
2393 <li>'<tt>function args</tt>': argument list whose types match the function
2394 signature argument types. If the function signature indicates the function
2395 accepts a variable number of arguments, the extra arguments can be
2396 specified. </li>
2397
2398 <li>'<tt>normal label</tt>': the label reached when the called function
2399 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2400
2401 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2402 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2403
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2404 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2405 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2406 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2407</ol>
2408
2409<h5>Semantics:</h5>
2410
2411<p>This instruction is designed to operate as a standard '<tt><a
2412href="#i_call">call</a></tt>' instruction in most regards. The primary
2413difference is that it establishes an association with a label, which is used by
2414the runtime library to unwind the stack.</p>
2415
2416<p>This instruction is used in languages with destructors to ensure that proper
2417cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2418exception. Additionally, this is important for implementation of
2419'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2420
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]2421<p>For the purposes of the SSA form, the definition of the value
2422returned by the '<tt>invoke</tt>' instruction is deemed to occur on
2423the edge from the current block to the "normal" label. If the callee
2424unwinds then no return value is available.</p>
Dan Gohman140ba5d2009-05-22 21:47:08 +0000[diff] [blame]2425
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2426<h5>Example:</h5>
2427<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2428 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2429 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2430 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2431 unwind label %TestCleanup <i>; {i32}:retval set</i>
2432</pre>
2433</div>
2434
2435
2436<!-- _______________________________________________________________________ -->
2437
2438<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2439Instruction</a> </div>
2440
2441<div class="doc_text">
2442
2443<h5>Syntax:</h5>
2444<pre>
2445 unwind
2446</pre>
2447
2448<h5>Overview:</h5>
2449
2450<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2451at the first callee in the dynamic call stack which used an <a
2452href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2453primarily used to implement exception handling.</p>
2454
2455<h5>Semantics:</h5>
2456
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2457<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2458immediately halt. The dynamic call stack is then searched for the first <a
2459href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2460execution continues at the "exceptional" destination block specified by the
2461<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2462dynamic call chain, undefined behavior results.</p>
2463</div>
2464
2465<!-- _______________________________________________________________________ -->
2466
2467<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2468Instruction</a> </div>
2469
2470<div class="doc_text">
2471
2472<h5>Syntax:</h5>
2473<pre>
2474 unreachable
2475</pre>
2476
2477<h5>Overview:</h5>
2478
2479<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2480instruction is used to inform the optimizer that a particular portion of the
2481code is not reachable. This can be used to indicate that the code after a
2482no-return function cannot be reached, and other facts.</p>
2483
2484<h5>Semantics:</h5>
2485
2486<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2487</div>
2488
2489
2490
2491<!-- ======================================================================= -->
2492<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2493<div class="doc_text">
2494<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2495program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496produce a single value. The operands might represent
2497multiple 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]2498The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2499<p>There are several different binary operators:</p>
2500</div>
2501<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502<div class="doc_subsubsection">
2503 <a name="i_add">'<tt>add</tt>' Instruction</a>
2504</div>
2505
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2507
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2509
2510<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2511 &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]2512</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2513
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2514<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2515
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2516<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2517
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2518<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2519
2520<p>The two arguments to the '<tt>add</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2521 href="#t_integer">integer</a> or
2522 <a href="#t_vector">vector</a> of integer values. Both arguments must
2523 have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2524
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2526
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2527<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2528
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2529<p>If the sum has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2530mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2531the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2532
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2533<p>Because LLVM integers use a two's complement representation, this
2534instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2536<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2537
2538<pre>
2539 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2540</pre>
2541</div>
2542<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2543<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2544 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
2545</div>
2546
2547<div class="doc_text">
2548
2549<h5>Syntax:</h5>
2550
2551<pre>
2552 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2553</pre>
2554
2555<h5>Overview:</h5>
2556
2557<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
2558
2559<h5>Arguments:</h5>
2560
2561<p>The two arguments to the '<tt>fadd</tt>' instruction must be
2562<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
2563floating point values. Both arguments must have identical types.</p>
2564
2565<h5>Semantics:</h5>
2566
2567<p>The value produced is the floating point sum of the two operands.</p>
2568
2569<h5>Example:</h5>
2570
2571<pre>
2572 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
2573</pre>
2574</div>
2575<!-- _______________________________________________________________________ -->
2576<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2577 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2578</div>
2579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2581
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2582<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2583
2584<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2585 &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]2586</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2587
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2588<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2589
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2590<p>The '<tt>sub</tt>' instruction returns the difference of its two
2591operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2592
2593<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2594'<tt>neg</tt>' instruction present in most other intermediate
2595representations.</p>
2596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2598
2599<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2600 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
2601 integer values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2602
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2603<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2604
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2605<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2606
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2607<p>If the difference has unsigned overflow, the result returned is the
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2608mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2609the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2610
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2611<p>Because LLVM integers use a two's complement representation, this
2612instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2614<h5>Example:</h5>
2615<pre>
2616 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2617 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2618</pre>
2619</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2620
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2622<div class="doc_subsubsection">
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2623 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
2624</div>
2625
2626<div class="doc_text">
2627
2628<h5>Syntax:</h5>
2629
2630<pre>
2631 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2632</pre>
2633
2634<h5>Overview:</h5>
2635
2636<p>The '<tt>fsub</tt>' instruction returns the difference of its two
2637operands.</p>
2638
2639<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
2640'<tt>fneg</tt>' instruction present in most other intermediate
2641representations.</p>
2642
2643<h5>Arguments:</h5>
2644
2645<p>The two arguments to the '<tt>fsub</tt>' instruction must be <a
2646 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2647 of floating point values. Both arguments must have identical types.</p>
2648
2649<h5>Semantics:</h5>
2650
2651<p>The value produced is the floating point difference of the two operands.</p>
2652
2653<h5>Example:</h5>
2654<pre>
2655 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
2656 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
2657</pre>
2658</div>
2659
2660<!-- _______________________________________________________________________ -->
2661<div class="doc_subsubsection">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2662 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2663</div>
2664
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2665<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2666
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2668<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]2669</pre>
2670<h5>Overview:</h5>
2671<p>The '<tt>mul</tt>' instruction returns the product of its two
2672operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2673
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2674<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2675
2676<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2677href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2678values. Both arguments must have identical types.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2679
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2680<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2681
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2682<p>The value produced is the integer product of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2683
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2684<p>If the result of the multiplication has unsigned overflow,
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2685the result returned is the mathematical result modulo
26862<sup>n</sup>, where n is the bit width of the result.</p>
2687<p>Because LLVM integers use a two's complement representation, and the
2688result is the same width as the operands, this instruction returns the
2689correct result for both signed and unsigned integers. If a full product
2690(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2691should be sign-extended or zero-extended as appropriate to the
2692width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<h5>Example:</h5>
2694<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2695</pre>
2696</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2697
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2698<!-- _______________________________________________________________________ -->
Dan Gohman7ce405e2009-06-04 22:49:04 +0000[diff] [blame]2699<div class="doc_subsubsection">
2700 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
2701</div>
2702
2703<div class="doc_text">
2704
2705<h5>Syntax:</h5>
2706<pre> &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
2707</pre>
2708<h5>Overview:</h5>
2709<p>The '<tt>fmul</tt>' instruction returns the product of its two
2710operands.</p>
2711
2712<h5>Arguments:</h5>
2713
2714<p>The two arguments to the '<tt>fmul</tt>' instruction must be
2715<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2716of floating point values. Both arguments must have identical types.</p>
2717
2718<h5>Semantics:</h5>
2719
2720<p>The value produced is the floating point product of the two operands.</p>
2721
2722<h5>Example:</h5>
2723<pre> &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
2724</pre>
2725</div>
2726
2727<!-- _______________________________________________________________________ -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2728<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2729</a></div>
2730<div class="doc_text">
2731<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2732<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]2733</pre>
2734<h5>Overview:</h5>
2735<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2736operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2737
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2738<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2739
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2740<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2741<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2742values. Both arguments must have identical types.</p>
2743
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2744<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2745
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2746<p>The value produced is the unsigned integer quotient of the two operands.</p>
2747<p>Note that unsigned integer division and signed integer division are distinct
2748operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2749<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2750<h5>Example:</h5>
2751<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2752</pre>
2753</div>
2754<!-- _______________________________________________________________________ -->
2755<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2756</a> </div>
2757<div class="doc_text">
2758<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2759<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2760 &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]2761</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2762
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2763<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2765<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2766operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2767
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2768<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2769
2770<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2771<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2772values. Both arguments must have identical types.</p>
2773
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2774<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2775<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]2776<p>Note that signed integer division and unsigned integer division are distinct
2777operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2778<p>Division by zero leads to undefined behavior. Overflow also leads to
2779undefined behavior; this is a rare case, but can occur, for example,
2780by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2781<h5>Example:</h5>
2782<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2783</pre>
2784</div>
2785<!-- _______________________________________________________________________ -->
2786<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2787Instruction</a> </div>
2788<div class="doc_text">
2789<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2790<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2791 &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]2792</pre>
2793<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2794
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2795<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2796operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2797
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2798<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2799
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2800<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2801<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2802of floating point values. Both arguments must have identical types.</p>
2803
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2805
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2806<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2807
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2808<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2809
2810<pre>
2811 &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]2812</pre>
2813</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2815<!-- _______________________________________________________________________ -->
2816<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2817</div>
2818<div class="doc_text">
2819<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2820<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]2821</pre>
2822<h5>Overview:</h5>
2823<p>The '<tt>urem</tt>' instruction returns the remainder from the
2824unsigned division of its two arguments.</p>
2825<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2826<p>The two arguments to the '<tt>urem</tt>' instruction must be
2827<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2828values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2829<h5>Semantics:</h5>
2830<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2831This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2832<p>Note that unsigned integer remainder and signed integer remainder are
2833distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2834<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2835<h5>Example:</h5>
2836<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2837</pre>
2838
2839</div>
2840<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2841<div class="doc_subsubsection">
2842 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2843</div>
2844
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2845<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2846
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2847<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2848
2849<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2850 &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]2851</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2852
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2853<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2854
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2855<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2856signed division of its two operands. This instruction can also take
2857<a href="#t_vector">vector</a> versions of the values in which case
2858the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2860<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2861
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2862<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2863<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2864values. Both arguments must have identical types.</p>
2865
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2866<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2867
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2868<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2869has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2870operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2871a value. For more information about the difference, see <a
2872 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2873Math Forum</a>. For a table of how this is implemented in various languages,
2874please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2875Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2876<p>Note that signed integer remainder and unsigned integer remainder are
2877distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2878<p>Taking the remainder of a division by zero leads to undefined behavior.
2879Overflow also leads to undefined behavior; this is a rare case, but can occur,
2880for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2881(The remainder doesn't actually overflow, but this rule lets srem be
2882implemented using instructions that return both the result of the division
2883and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2884<h5>Example:</h5>
2885<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2886</pre>
2887
2888</div>
2889<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2890<div class="doc_subsubsection">
2891 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2892
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2893<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2895<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2896<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]2897</pre>
2898<h5>Overview:</h5>
2899<p>The '<tt>frem</tt>' instruction returns the remainder from the
2900division of its two operands.</p>
2901<h5>Arguments:</h5>
2902<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2903<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2904of floating point values. Both arguments must have identical types.</p>
2905
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2906<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2907
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2908<p>This instruction returns the <i>remainder</i> of a division.
2909The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2910
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2911<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2912
2913<pre>
2914 &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]2915</pre>
2916</div>
2917
2918<!-- ======================================================================= -->
2919<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2920Operations</a> </div>
2921<div class="doc_text">
2922<p>Bitwise binary operators are used to do various forms of
2923bit-twiddling in a program. They are generally very efficient
2924instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2925instructions. They require two operands of the same type, execute an operation on them,
2926and 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]2927</div>
2928
2929<!-- _______________________________________________________________________ -->
2930<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2931Instruction</a> </div>
2932<div class="doc_text">
2933<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2934<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]2935</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2936
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2937<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2938
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2939<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2940the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2941
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2942<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2943
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2944<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2945 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2946type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2947
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2948<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2949
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2950<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2951where 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]2952equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2953If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2954corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2955
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2956<h5>Example:</h5><pre>
2957 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2958 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2959 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2960 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2961 &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]2962</pre>
2963</div>
2964<!-- _______________________________________________________________________ -->
2965<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2966Instruction</a> </div>
2967<div class="doc_text">
2968<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2969<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]2970</pre>
2971
2972<h5>Overview:</h5>
2973<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2974operand shifted to the right a specified number of bits with zero fill.</p>
2975
2976<h5>Arguments:</h5>
2977<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2978<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]2979type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980
2981<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2982
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2983<p>This instruction always performs a logical shift right operation. The most
2984significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2985shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2986the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2987vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2988amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2989
2990<h5>Example:</h5>
2991<pre>
2992 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2993 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2994 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2995 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2996 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2997 &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]2998</pre>
2999</div>
3000
3001<!-- _______________________________________________________________________ -->
3002<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
3003Instruction</a> </div>
3004<div class="doc_text">
3005
3006<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3007<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]3008</pre>
3009
3010<h5>Overview:</h5>
3011<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
3012operand shifted to the right a specified number of bits with sign extension.</p>
3013
3014<h5>Arguments:</h5>
3015<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]3016<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]3017type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3018
3019<h5>Semantics:</h5>
3020<p>This instruction always performs an arithmetic shift right operation,
3021The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3022of <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]3023larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
3024arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
3025corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3026
3027<h5>Example:</h5>
3028<pre>
3029 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
3030 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
3031 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
3032 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]3033 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]3034 &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]3035</pre>
3036</div>
3037
3038<!-- _______________________________________________________________________ -->
3039<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
3040Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3041
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3042<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3043
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3044<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3045
3046<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3047 &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]3048</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3049
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3050<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3051
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3052<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
3053its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3054
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3055<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3056
3057<p>The two arguments to the '<tt>and</tt>' instruction must be
3058<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3059values. Both arguments must have identical types.</p>
3060
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3061<h5>Semantics:</h5>
3062<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
3063<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3064<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3065<table border="1" cellspacing="0" cellpadding="4">
3066 <tbody>
3067 <tr>
3068 <td>In0</td>
3069 <td>In1</td>
3070 <td>Out</td>
3071 </tr>
3072 <tr>
3073 <td>0</td>
3074 <td>0</td>
3075 <td>0</td>
3076 </tr>
3077 <tr>
3078 <td>0</td>
3079 <td>1</td>
3080 <td>0</td>
3081 </tr>
3082 <tr>
3083 <td>1</td>
3084 <td>0</td>
3085 <td>0</td>
3086 </tr>
3087 <tr>
3088 <td>1</td>
3089 <td>1</td>
3090 <td>1</td>
3091 </tr>
3092 </tbody>
3093</table>
3094</div>
3095<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3096<pre>
3097 &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]3098 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
3099 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
3100</pre>
3101</div>
3102<!-- _______________________________________________________________________ -->
3103<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
3104<div class="doc_text">
3105<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3106<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]3107</pre>
3108<h5>Overview:</h5>
3109<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
3110or of its two operands.</p>
3111<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3112
3113<p>The two arguments to the '<tt>or</tt>' instruction must be
3114<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3115values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3116<h5>Semantics:</h5>
3117<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
3118<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3119<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3120<table border="1" cellspacing="0" cellpadding="4">
3121 <tbody>
3122 <tr>
3123 <td>In0</td>
3124 <td>In1</td>
3125 <td>Out</td>
3126 </tr>
3127 <tr>
3128 <td>0</td>
3129 <td>0</td>
3130 <td>0</td>
3131 </tr>
3132 <tr>
3133 <td>0</td>
3134 <td>1</td>
3135 <td>1</td>
3136 </tr>
3137 <tr>
3138 <td>1</td>
3139 <td>0</td>
3140 <td>1</td>
3141 </tr>
3142 <tr>
3143 <td>1</td>
3144 <td>1</td>
3145 <td>1</td>
3146 </tr>
3147 </tbody>
3148</table>
3149</div>
3150<h5>Example:</h5>
3151<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3152 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3153 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
3154</pre>
3155</div>
3156<!-- _______________________________________________________________________ -->
3157<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3158Instruction</a> </div>
3159<div class="doc_text">
3160<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3161<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]3162</pre>
3163<h5>Overview:</h5>
3164<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3165or of its two operands. The <tt>xor</tt> is used to implement the
3166"one's complement" operation, which is the "~" operator in C.</p>
3167<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3168<p>The two arguments to the '<tt>xor</tt>' instruction must be
3169<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3170values. Both arguments must have identical types.</p>
3171
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3173
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3174<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
3175<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]3176<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3177<table border="1" cellspacing="0" cellpadding="4">
3178 <tbody>
3179 <tr>
3180 <td>In0</td>
3181 <td>In1</td>
3182 <td>Out</td>
3183 </tr>
3184 <tr>
3185 <td>0</td>
3186 <td>0</td>
3187 <td>0</td>
3188 </tr>
3189 <tr>
3190 <td>0</td>
3191 <td>1</td>
3192 <td>1</td>
3193 </tr>
3194 <tr>
3195 <td>1</td>
3196 <td>0</td>
3197 <td>1</td>
3198 </tr>
3199 <tr>
3200 <td>1</td>
3201 <td>1</td>
3202 <td>0</td>
3203 </tr>
3204 </tbody>
3205</table>
3206</div>
3207<p> </p>
3208<h5>Example:</h5>
3209<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3210 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3211 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3212 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
3213</pre>
3214</div>
3215
3216<!-- ======================================================================= -->
3217<div class="doc_subsection">
3218 <a name="vectorops">Vector Operations</a>
3219</div>
3220
3221<div class="doc_text">
3222
3223<p>LLVM supports several instructions to represent vector operations in a
3224target-independent manner. These instructions cover the element-access and
3225vector-specific operations needed to process vectors effectively. While LLVM
3226does directly support these vector operations, many sophisticated algorithms
3227will want to use target-specific intrinsics to take full advantage of a specific
3228target.</p>
3229
3230</div>
3231
3232<!-- _______________________________________________________________________ -->
3233<div class="doc_subsubsection">
3234 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3235</div>
3236
3237<div class="doc_text">
3238
3239<h5>Syntax:</h5>
3240
3241<pre>
3242 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
3243</pre>
3244
3245<h5>Overview:</h5>
3246
3247<p>
3248The '<tt>extractelement</tt>' instruction extracts a single scalar
3249element from a vector at a specified index.
3250</p>
3251
3252
3253<h5>Arguments:</h5>
3254
3255<p>
3256The first operand of an '<tt>extractelement</tt>' instruction is a
3257value of <a href="#t_vector">vector</a> type. The second operand is
3258an index indicating the position from which to extract the element.
3259The index may be a variable.</p>
3260
3261<h5>Semantics:</h5>
3262
3263<p>
3264The result is a scalar of the same type as the element type of
3265<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3266<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3267results are undefined.
3268</p>
3269
3270<h5>Example:</h5>
3271
3272<pre>
3273 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
3274</pre>
3275</div>
3276
3277
3278<!-- _______________________________________________________________________ -->
3279<div class="doc_subsubsection">
3280 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3281</div>
3282
3283<div class="doc_text">
3284
3285<h5>Syntax:</h5>
3286
3287<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]3288 &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]3289</pre>
3290
3291<h5>Overview:</h5>
3292
3293<p>
3294The '<tt>insertelement</tt>' instruction inserts a scalar
3295element into a vector at a specified index.
3296</p>
3297
3298
3299<h5>Arguments:</h5>
3300
3301<p>
3302The first operand of an '<tt>insertelement</tt>' instruction is a
3303value of <a href="#t_vector">vector</a> type. The second operand is a
3304scalar value whose type must equal the element type of the first
3305operand. The third operand is an index indicating the position at
3306which to insert the value. The index may be a variable.</p>
3307
3308<h5>Semantics:</h5>
3309
3310<p>
3311The result is a vector of the same type as <tt>val</tt>. Its
3312element values are those of <tt>val</tt> except at position
3313<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3314exceeds the length of <tt>val</tt>, the results are undefined.
3315</p>
3316
3317<h5>Example:</h5>
3318
3319<pre>
3320 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
3321</pre>
3322</div>
3323
3324<!-- _______________________________________________________________________ -->
3325<div class="doc_subsubsection">
3326 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3327</div>
3328
3329<div class="doc_text">
3330
3331<h5>Syntax:</h5>
3332
3333<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3334 &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]3335</pre>
3336
3337<h5>Overview:</h5>
3338
3339<p>
3340The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3341from two input vectors, returning a vector with the same element type as
3342the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3343</p>
3344
3345<h5>Arguments:</h5>
3346
3347<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3348The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3349with types that match each other. The third argument is a shuffle mask whose
3350element type is always 'i32'. The result of the instruction is a vector whose
3351length is the same as the shuffle mask and whose element type is the same as
3352the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3353</p>
3354
3355<p>
3356The shuffle mask operand is required to be a constant vector with either
3357constant integer or undef values.
3358</p>
3359
3360<h5>Semantics:</h5>
3361
3362<p>
3363The elements of the two input vectors are numbered from left to right across
3364both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3365the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3366gets. The element selector may be undef (meaning "don't care") and the second
3367operand may be undef if performing a shuffle from only one vector.
3368</p>
3369
3370<h5>Example:</h5>
3371
3372<pre>
3373 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3374 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3375 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3376 &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]3377 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3378 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3379 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3380 &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]3381</pre>
3382</div>
3383
3384
3385<!-- ======================================================================= -->
3386<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3387 <a name="aggregateops">Aggregate Operations</a>
3388</div>
3389
3390<div class="doc_text">
3391
3392<p>LLVM supports several instructions for working with aggregate values.
3393</p>
3394
3395</div>
3396
3397<!-- _______________________________________________________________________ -->
3398<div class="doc_subsubsection">
3399 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3400</div>
3401
3402<div class="doc_text">
3403
3404<h5>Syntax:</h5>
3405
3406<pre>
3407 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3408</pre>
3409
3410<h5>Overview:</h5>
3411
3412<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3413The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3414or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3415</p>
3416
3417
3418<h5>Arguments:</h5>
3419
3420<p>
3421The first operand of an '<tt>extractvalue</tt>' instruction is a
3422value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3423type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3424in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3425'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3426</p>
3427
3428<h5>Semantics:</h5>
3429
3430<p>
3431The result is the value at the position in the aggregate specified by
3432the index operands.
3433</p>
3434
3435<h5>Example:</h5>
3436
3437<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3438 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3439</pre>
3440</div>
3441
3442
3443<!-- _______________________________________________________________________ -->
3444<div class="doc_subsubsection">
3445 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3446</div>
3447
3448<div class="doc_text">
3449
3450<h5>Syntax:</h5>
3451
3452<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3453 &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]3454</pre>
3455
3456<h5>Overview:</h5>
3457
3458<p>
3459The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3460into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3461</p>
3462
3463
3464<h5>Arguments:</h5>
3465
3466<p>
3467The first operand of an '<tt>insertvalue</tt>' instruction is a
3468value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3469The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3470The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3471indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3472indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3473'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3474The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3475by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3476</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3477
3478<h5>Semantics:</h5>
3479
3480<p>
3481The result is an aggregate of the same type as <tt>val</tt>. Its
3482value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3483specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3484</p>
3485
3486<h5>Example:</h5>
3487
3488<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3489 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3490</pre>
3491</div>
3492
3493
3494<!-- ======================================================================= -->
3495<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3496 <a name="memoryops">Memory Access and Addressing Operations</a>
3497</div>
3498
3499<div class="doc_text">
3500
3501<p>A key design point of an SSA-based representation is how it
3502represents memory. In LLVM, no memory locations are in SSA form, which
3503makes things very simple. This section describes how to read, write,
3504allocate, and free memory in LLVM.</p>
3505
3506</div>
3507
3508<!-- _______________________________________________________________________ -->
3509<div class="doc_subsubsection">
3510 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3511</div>
3512
3513<div class="doc_text">
3514
3515<h5>Syntax:</h5>
3516
3517<pre>
3518 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3519</pre>
3520
3521<h5>Overview:</h5>
3522
3523<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3524heap and returns a pointer to it. The object is always allocated in the generic
3525address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3526
3527<h5>Arguments:</h5>
3528
3529<p>The '<tt>malloc</tt>' instruction allocates
3530<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3531bytes of memory from the operating system and returns a pointer of the
3532appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3533number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3534If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3535be aligned to at least that boundary. If not specified, or if zero, the target can
3536choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3537
3538<p>'<tt>type</tt>' must be a sized type.</p>
3539
3540<h5>Semantics:</h5>
3541
3542<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3543a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3544result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3545
3546<h5>Example:</h5>
3547
3548<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3549 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3550
3551 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3552 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3553 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3554 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3555 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3556</pre>
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]3557
3558<p>Note that the code generator does not yet respect the
3559 alignment value.</p>
3560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3561</div>
3562
3563<!-- _______________________________________________________________________ -->
3564<div class="doc_subsubsection">
3565 <a name="i_free">'<tt>free</tt>' Instruction</a>
3566</div>
3567
3568<div class="doc_text">
3569
3570<h5>Syntax:</h5>
3571
3572<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3573 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3574</pre>
3575
3576<h5>Overview:</h5>
3577
3578<p>The '<tt>free</tt>' instruction returns memory back to the unused
3579memory heap to be reallocated in the future.</p>
3580
3581<h5>Arguments:</h5>
3582
3583<p>'<tt>value</tt>' shall be a pointer value that points to a value
3584that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3585instruction.</p>
3586
3587<h5>Semantics:</h5>
3588
3589<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3590after this instruction executes. If the pointer is null, the operation
3591is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3592
3593<h5>Example:</h5>
3594
3595<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3596 %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]3597 free [4 x i8]* %array
3598</pre>
3599</div>
3600
3601<!-- _______________________________________________________________________ -->
3602<div class="doc_subsubsection">
3603 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3604</div>
3605
3606<div class="doc_text">
3607
3608<h5>Syntax:</h5>
3609
3610<pre>
3611 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3612</pre>
3613
3614<h5>Overview:</h5>
3615
3616<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3617currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3618returns to its caller. The object is always allocated in the generic address
3619space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3620
3621<h5>Arguments:</h5>
3622
3623<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3624bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3625appropriate type to the program. If "NumElements" is specified, it is the
3626number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3627If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3628to be aligned to at least that boundary. If not specified, or if zero, the target
3629can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3630
3631<p>'<tt>type</tt>' may be any sized type.</p>
3632
3633<h5>Semantics:</h5>
3634
Bill Wendling2a454572009-05-08 20:49:29 +0000[diff] [blame]3635<p>Memory is allocated; a pointer is returned. The operation is undefined if
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3636there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3637memory is automatically released when the function returns. The '<tt>alloca</tt>'
3638instruction is commonly used to represent automatic variables that must
3639have an address available. When the function returns (either with the <tt><a
3640 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]3641instructions), the memory is reclaimed. Allocating zero bytes
3642is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3643
3644<h5>Example:</h5>
3645
3646<pre>
Dan Gohmanf54f50a2009-01-04 23:49:44 +0000[diff] [blame]3647 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3648 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3649 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3650 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3651</pre>
3652</div>
3653
3654<!-- _______________________________________________________________________ -->
3655<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3656Instruction</a> </div>
3657<div class="doc_text">
3658<h5>Syntax:</h5>
3659<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>
3660<h5>Overview:</h5>
3661<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3662<h5>Arguments:</h5>
3663<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3664address from which to load. The pointer must point to a <a
3665 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3666marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3667the number or order of execution of this <tt>load</tt> with other
3668volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3669instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3670<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3671The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3672(that is, the alignment of the memory address). A value of 0 or an
3673omitted "align" argument means that the operation has the preferential
3674alignment for the target. It is the responsibility of the code emitter
3675to ensure that the alignment information is correct. Overestimating
3676the alignment results in an undefined behavior. Underestimating the
3677alignment may produce less efficient code. An alignment of 1 is always
3678safe.
3679</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3680<h5>Semantics:</h5>
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3681<p>The location of memory pointed to is loaded. If the value being loaded
3682is of scalar type then the number of bytes read does not exceed the minimum
3683number of bytes needed to hold all bits of the type. For example, loading an
3684<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3685<tt>i20</tt> with a size that is not an integral number of bytes, the result
3686is undefined if the value was not originally written using a store of the
3687same type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3688<h5>Examples:</h5>
3689<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3690 <a
3691 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3692 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3693</pre>
3694</div>
3695<!-- _______________________________________________________________________ -->
3696<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3697Instruction</a> </div>
3698<div class="doc_text">
3699<h5>Syntax:</h5>
3700<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3701 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3702</pre>
3703<h5>Overview:</h5>
3704<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3705<h5>Arguments:</h5>
3706<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3707to 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]3708operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3709of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3711optimizer is not allowed to modify the number or order of execution of
3712this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3713 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3714<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3715The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3716(that is, the alignment of the memory address). A value of 0 or an
3717omitted "align" argument means that the operation has the preferential
3718alignment for the target. It is the responsibility of the code emitter
3719to ensure that the alignment information is correct. Overestimating
3720the alignment results in an undefined behavior. Underestimating the
3721alignment may produce less efficient code. An alignment of 1 is always
3722safe.
3723</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3724<h5>Semantics:</h5>
3725<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsfe87fff2009-03-22 11:33:16 +0000[diff] [blame]3726at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3727If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3728written does not exceed the minimum number of bytes needed to hold all
3729bits of the type. For example, storing an <tt>i24</tt> writes at most
3730three bytes. When writing a value of a type like <tt>i20</tt> with a
3731size that is not an integral number of bytes, it is unspecified what
3732happens to the extra bits that do not belong to the type, but they will
3733typically be overwritten.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3734<h5>Example:</h5>
3735<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3736 store i32 3, i32* %ptr <i>; yields {void}</i>
3737 %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]3738</pre>
3739</div>
3740
3741<!-- _______________________________________________________________________ -->
3742<div class="doc_subsubsection">
3743 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3744</div>
3745
3746<div class="doc_text">
3747<h5>Syntax:</h5>
3748<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3749 &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]3750</pre>
3751
3752<h5>Overview:</h5>
3753
3754<p>
3755The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3756subelement of an aggregate data structure. It performs address calculation only
3757and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3758
3759<h5>Arguments:</h5>
3760
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3761<p>The first argument is always a pointer, and forms the basis of the
3762calculation. The remaining arguments are indices, that indicate which of the
3763elements of the aggregate object are indexed. The interpretation of each index
3764is dependent on the type being indexed into. The first index always indexes the
3765pointer value given as the first argument, the second index indexes a value of
3766the type pointed to (not necessarily the value directly pointed to, since the
3767first index can be non-zero), etc. The first type indexed into must be a pointer
3768value, subsequent types can be arrays, vectors and structs. Note that subsequent
3769types being indexed into can never be pointers, since that would require loading
3770the pointer before continuing calculation.</p>
3771
3772<p>The type of each index argument depends on the type it is indexing into.
3773When indexing into a (packed) structure, only <tt>i32</tt> integer
3774<b>constants</b> are allowed. When indexing into an array, pointer or vector,
Sanjiv Guptaa2e72d92009-04-27 03:21:00 +0000[diff] [blame]3775integers of any width are allowed (also non-constants).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3776
3777<p>For example, let's consider a C code fragment and how it gets
3778compiled to LLVM:</p>
3779
3780<div class="doc_code">
3781<pre>
3782struct RT {
3783 char A;
3784 int B[10][20];
3785 char C;
3786};
3787struct ST {
3788 int X;
3789 double Y;
3790 struct RT Z;
3791};
3792
3793int *foo(struct ST *s) {
3794 return &amp;s[1].Z.B[5][13];
3795}
3796</pre>
3797</div>
3798
3799<p>The LLVM code generated by the GCC frontend is:</p>
3800
3801<div class="doc_code">
3802<pre>
Chris Lattner5b6dc6e2009-01-11 20:53:49 +0000[diff] [blame]3803%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3804%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3805
3806define i32* %foo(%ST* %s) {
3807entry:
3808 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3809 ret i32* %reg
3810}
3811</pre>
3812</div>
3813
3814<h5>Semantics:</h5>
3815
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3816<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3817type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3818}</tt>' type, a structure. The second index indexes into the third element of
3819the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3820i8 }</tt>' type, another structure. The third index indexes into the second
3821element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3822array. The two dimensions of the array are subscripted into, yielding an
3823'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3824to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3825
3826<p>Note that it is perfectly legal to index partially through a
3827structure, returning a pointer to an inner element. Because of this,
3828the LLVM code for the given testcase is equivalent to:</p>
3829
3830<pre>
3831 define i32* %foo(%ST* %s) {
3832 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3833 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3834 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3835 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3836 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3837 ret i32* %t5
3838 }
3839</pre>
3840
Chris Lattner50609942009-03-09 20:55:18 +0000[diff] [blame]3841<p>Note that it is undefined to access an array out of bounds: array
3842and pointer indexes must always be within the defined bounds of the
3843array type when accessed with an instruction that dereferences the
3844pointer (e.g. a load or store instruction). The one exception for
3845this rule is zero length arrays. These arrays are defined to be
3846accessible as variable length arrays, which requires access beyond the
3847zero'th element.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3848
3849<p>The getelementptr instruction is often confusing. For some more insight
3850into how it works, see <a href="GetElementPtr.html">the getelementptr
3851FAQ</a>.</p>
3852
3853<h5>Example:</h5>
3854
3855<pre>
3856 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3857 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3858 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3859 %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]3860 <i>; yields i8*:eptr</i>
3861 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta4f9a0dc2009-04-25 07:27:44 +0000[diff] [blame]3862 <i>; yields i32*:iptr</i>
Sanjiv Gupta1e46c582009-04-24 16:38:13 +0000[diff] [blame]3863 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3864</pre>
3865</div>
3866
3867<!-- ======================================================================= -->
3868<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3869</div>
3870<div class="doc_text">
3871<p>The instructions in this category are the conversion instructions (casting)
3872which all take a single operand and a type. They perform various bit conversions
3873on the operand.</p>
3874</div>
3875
3876<!-- _______________________________________________________________________ -->
3877<div class="doc_subsubsection">
3878 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3879</div>
3880<div class="doc_text">
3881
3882<h5>Syntax:</h5>
3883<pre>
3884 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3885</pre>
3886
3887<h5>Overview:</h5>
3888<p>
3889The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3890</p>
3891
3892<h5>Arguments:</h5>
3893<p>
3894The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3895be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3896and type of the result, which must be an <a href="#t_integer">integer</a>
3897type. The bit size of <tt>value</tt> must be larger than the bit size of
3898<tt>ty2</tt>. Equal sized types are not allowed.</p>
3899
3900<h5>Semantics:</h5>
3901<p>
3902The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3903and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3904larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3905It will always truncate bits.</p>
3906
3907<h5>Example:</h5>
3908<pre>
3909 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3910 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3911 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3912</pre>
3913</div>
3914
3915<!-- _______________________________________________________________________ -->
3916<div class="doc_subsubsection">
3917 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3918</div>
3919<div class="doc_text">
3920
3921<h5>Syntax:</h5>
3922<pre>
3923 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3924</pre>
3925
3926<h5>Overview:</h5>
3927<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3928<tt>ty2</tt>.</p>
3929
3930
3931<h5>Arguments:</h5>
3932<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3933<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3934also be of <a href="#t_integer">integer</a> type. The bit size of the
3935<tt>value</tt> must be smaller than the bit size of the destination type,
3936<tt>ty2</tt>.</p>
3937
3938<h5>Semantics:</h5>
3939<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3940bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3941
3942<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3943
3944<h5>Example:</h5>
3945<pre>
3946 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3947 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3948</pre>
3949</div>
3950
3951<!-- _______________________________________________________________________ -->
3952<div class="doc_subsubsection">
3953 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3954</div>
3955<div class="doc_text">
3956
3957<h5>Syntax:</h5>
3958<pre>
3959 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3960</pre>
3961
3962<h5>Overview:</h5>
3963<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3964
3965<h5>Arguments:</h5>
3966<p>
3967The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3968<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3969also be of <a href="#t_integer">integer</a> type. The bit size of the
3970<tt>value</tt> must be smaller than the bit size of the destination type,
3971<tt>ty2</tt>.</p>
3972
3973<h5>Semantics:</h5>
3974<p>
3975The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3976bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3977the type <tt>ty2</tt>.</p>
3978
3979<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3980
3981<h5>Example:</h5>
3982<pre>
3983 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3984 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3985</pre>
3986</div>
3987
3988<!-- _______________________________________________________________________ -->
3989<div class="doc_subsubsection">
3990 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3991</div>
3992
3993<div class="doc_text">
3994
3995<h5>Syntax:</h5>
3996
3997<pre>
3998 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3999</pre>
4000
4001<h5>Overview:</h5>
4002<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
4003<tt>ty2</tt>.</p>
4004
4005
4006<h5>Arguments:</h5>
4007<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
4008 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
4009cast it to. The size of <tt>value</tt> must be larger than the size of
4010<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
4011<i>no-op cast</i>.</p>
4012
4013<h5>Semantics:</h5>
4014<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
4015<a href="#t_floating">floating point</a> type to a smaller
4016<a href="#t_floating">floating point</a> type. If the value cannot fit within
4017the destination type, <tt>ty2</tt>, then the results are undefined.</p>
4018
4019<h5>Example:</h5>
4020<pre>
4021 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
4022 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
4023</pre>
4024</div>
4025
4026<!-- _______________________________________________________________________ -->
4027<div class="doc_subsubsection">
4028 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
4029</div>
4030<div class="doc_text">
4031
4032<h5>Syntax:</h5>
4033<pre>
4034 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4035</pre>
4036
4037<h5>Overview:</h5>
4038<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
4039floating point value.</p>
4040
4041<h5>Arguments:</h5>
4042<p>The '<tt>fpext</tt>' instruction takes a
4043<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
4044and a <a href="#t_floating">floating point</a> type to cast it to. The source
4045type must be smaller than the destination type.</p>
4046
4047<h5>Semantics:</h5>
4048<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
4049<a href="#t_floating">floating point</a> type to a larger
4050<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
4051used to make a <i>no-op cast</i> because it always changes bits. Use
4052<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
4053
4054<h5>Example:</h5>
4055<pre>
4056 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
4057 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
4058</pre>
4059</div>
4060
4061<!-- _______________________________________________________________________ -->
4062<div class="doc_subsubsection">
4063 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
4064</div>
4065<div class="doc_text">
4066
4067<h5>Syntax:</h5>
4068<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4069 &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]4070</pre>
4071
4072<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4073<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074unsigned integer equivalent of type <tt>ty2</tt>.
4075</p>
4076
4077<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4078<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]4079scalar or vector <a href="#t_floating">floating point</a> value, and a type
4080to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4081type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4082vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083
4084<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4085<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4086<a href="#t_floating">floating point</a> operand into the nearest (rounding
4087towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
4088the results are undefined.</p>
4089
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4090<h5>Example:</h5>
4091<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4092 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4093 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]4094 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095</pre>
4096</div>
4097
4098<!-- _______________________________________________________________________ -->
4099<div class="doc_subsubsection">
4100 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
4101</div>
4102<div class="doc_text">
4103
4104<h5>Syntax:</h5>
4105<pre>
4106 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4107</pre>
4108
4109<h5>Overview:</h5>
4110<p>The '<tt>fptosi</tt>' instruction converts
4111<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
4112</p>
4113
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4114<h5>Arguments:</h5>
4115<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]4116scalar or vector <a href="#t_floating">floating point</a> value, and a type
4117to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
4118type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
4119vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4120
4121<h5>Semantics:</h5>
4122<p>The '<tt>fptosi</tt>' instruction converts its
4123<a href="#t_floating">floating point</a> operand into the nearest (rounding
4124towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
4125the results are undefined.</p>
4126
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4127<h5>Example:</h5>
4128<pre>
4129 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]4130 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4131 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
4132</pre>
4133</div>
4134
4135<!-- _______________________________________________________________________ -->
4136<div class="doc_subsubsection">
4137 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
4138</div>
4139<div class="doc_text">
4140
4141<h5>Syntax:</h5>
4142<pre>
4143 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4144</pre>
4145
4146<h5>Overview:</h5>
4147<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
4148integer and converts that value to the <tt>ty2</tt> type.</p>
4149
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4150<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4151<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4152scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4153to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4154type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4155floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4156
4157<h5>Semantics:</h5>
4158<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
4159integer quantity and converts it to the corresponding floating point value. If
4160the value cannot fit in the floating point value, the results are undefined.</p>
4161
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4162<h5>Example:</h5>
4163<pre>
4164 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4165 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4166</pre>
4167</div>
4168
4169<!-- _______________________________________________________________________ -->
4170<div class="doc_subsubsection">
4171 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
4172</div>
4173<div class="doc_text">
4174
4175<h5>Syntax:</h5>
4176<pre>
4177 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4178</pre>
4179
4180<h5>Overview:</h5>
4181<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
4182integer and converts that value to the <tt>ty2</tt> type.</p>
4183
4184<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]4185<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4186scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4187to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4188type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4189floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4190
4191<h5>Semantics:</h5>
4192<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
4193integer quantity and converts it to the corresponding floating point value. If
4194the value cannot fit in the floating point value, the results are undefined.</p>
4195
4196<h5>Example:</h5>
4197<pre>
4198 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4199 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4200</pre>
4201</div>
4202
4203<!-- _______________________________________________________________________ -->
4204<div class="doc_subsubsection">
4205 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4206</div>
4207<div class="doc_text">
4208
4209<h5>Syntax:</h5>
4210<pre>
4211 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4212</pre>
4213
4214<h5>Overview:</h5>
4215<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4216the integer type <tt>ty2</tt>.</p>
4217
4218<h5>Arguments:</h5>
4219<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
4220must 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]4221<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]4222
4223<h5>Semantics:</h5>
4224<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4225<tt>ty2</tt> by interpreting the pointer value as an integer and either
4226truncating or zero extending that value to the size of the integer type. If
4227<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4228<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
4229are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4230change.</p>
4231
4232<h5>Example:</h5>
4233<pre>
4234 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4235 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
4236</pre>
4237</div>
4238
4239<!-- _______________________________________________________________________ -->
4240<div class="doc_subsubsection">
4241 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4242</div>
4243<div class="doc_text">
4244
4245<h5>Syntax:</h5>
4246<pre>
4247 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4248</pre>
4249
4250<h5>Overview:</h5>
4251<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4252a pointer type, <tt>ty2</tt>.</p>
4253
4254<h5>Arguments:</h5>
4255<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
4256value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4257<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4258
4259<h5>Semantics:</h5>
4260<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4261<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4262the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4263size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4264the size of a pointer then a zero extension is done. If they are the same size,
4265nothing is done (<i>no-op cast</i>).</p>
4266
4267<h5>Example:</h5>
4268<pre>
4269 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4270 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4271 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
4272</pre>
4273</div>
4274
4275<!-- _______________________________________________________________________ -->
4276<div class="doc_subsubsection">
4277 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
4278</div>
4279<div class="doc_text">
4280
4281<h5>Syntax:</h5>
4282<pre>
4283 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4284</pre>
4285
4286<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4287
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4288<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4289<tt>ty2</tt> without changing any bits.</p>
4290
4291<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4293<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]4294a non-aggregate first class value, and a type to cast it to, which must also be
4295a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4296<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4297and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4298type is a pointer, the destination type must also be a pointer. This
4299instruction supports bitwise conversion of vectors to integers and to vectors
4300of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4301
4302<h5>Semantics:</h5>
4303<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
4304<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4305this conversion. The conversion is done as if the <tt>value</tt> had been
4306stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4307converted to other pointer types with this instruction. To convert pointers to
4308other types, use the <a href="#i_inttoptr">inttoptr</a> or
4309<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
4310
4311<h5>Example:</h5>
4312<pre>
4313 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
4314 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4315 %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]4316</pre>
4317</div>
4318
4319<!-- ======================================================================= -->
4320<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4321<div class="doc_text">
4322<p>The instructions in this category are the "miscellaneous"
4323instructions, which defy better classification.</p>
4324</div>
4325
4326<!-- _______________________________________________________________________ -->
4327<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4328</div>
4329<div class="doc_text">
4330<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4331<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]4332</pre>
4333<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4334<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4335a vector of boolean values based on comparison
4336of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4337<h5>Arguments:</h5>
4338<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
4339the condition code indicating the kind of comparison to perform. It is not
4340a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4341</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342<ol>
4343 <li><tt>eq</tt>: equal</li>
4344 <li><tt>ne</tt>: not equal </li>
4345 <li><tt>ugt</tt>: unsigned greater than</li>
4346 <li><tt>uge</tt>: unsigned greater or equal</li>
4347 <li><tt>ult</tt>: unsigned less than</li>
4348 <li><tt>ule</tt>: unsigned less or equal</li>
4349 <li><tt>sgt</tt>: signed greater than</li>
4350 <li><tt>sge</tt>: signed greater or equal</li>
4351 <li><tt>slt</tt>: signed less than</li>
4352 <li><tt>sle</tt>: signed less or equal</li>
4353</ol>
4354<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4355<a href="#t_pointer">pointer</a>
4356or integer <a href="#t_vector">vector</a> typed.
4357They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4358<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4359<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]4360the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4361yields 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]4362</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4363<ol>
4364 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4365 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4366 </li>
4367 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4368 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4370 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4371 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4372 <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]4373 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4374 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4375 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4376 <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]4377 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4378 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4379 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4380 <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]4381 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4382 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4383 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4384 <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]4385</ol>
4386<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4387values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4388<p>If the operands are integer vectors, then they are compared
4389element by element. The result is an <tt>i1</tt> vector with
4390the same number of elements as the values being compared.
4391Otherwise, the result is an <tt>i1</tt>.
4392</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4393
4394<h5>Example:</h5>
4395<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4396 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4397 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4398 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4399 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4400 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4401</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4402
4403<p>Note that the code generator does not yet support vector types with
4404 the <tt>icmp</tt> instruction.</p>
4405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4406</div>
4407
4408<!-- _______________________________________________________________________ -->
4409<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4410</div>
4411<div class="doc_text">
4412<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4413<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]4414</pre>
4415<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4416<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4417or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4418of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4419<p>
4420If the operands are floating point scalars, then the result
4421type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4422</p>
4423<p>If the operands are floating point vectors, then the result type
4424is a vector of boolean with the same number of elements as the
4425operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4426<h5>Arguments:</h5>
4427<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4428the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4429a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4430<ol>
4431 <li><tt>false</tt>: no comparison, always returns false</li>
4432 <li><tt>oeq</tt>: ordered and equal</li>
4433 <li><tt>ogt</tt>: ordered and greater than </li>
4434 <li><tt>oge</tt>: ordered and greater than or equal</li>
4435 <li><tt>olt</tt>: ordered and less than </li>
4436 <li><tt>ole</tt>: ordered and less than or equal</li>
4437 <li><tt>one</tt>: ordered and not equal</li>
4438 <li><tt>ord</tt>: ordered (no nans)</li>
4439 <li><tt>ueq</tt>: unordered or equal</li>
4440 <li><tt>ugt</tt>: unordered or greater than </li>
4441 <li><tt>uge</tt>: unordered or greater than or equal</li>
4442 <li><tt>ult</tt>: unordered or less than </li>
4443 <li><tt>ule</tt>: unordered or less than or equal</li>
4444 <li><tt>une</tt>: unordered or not equal</li>
4445 <li><tt>uno</tt>: unordered (either nans)</li>
4446 <li><tt>true</tt>: no comparison, always returns true</li>
4447</ol>
4448<p><i>Ordered</i> means that neither operand is a QNAN while
4449<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4450<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4451either a <a href="#t_floating">floating point</a> type
4452or a <a href="#t_vector">vector</a> of floating point type.
4453They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4454<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4455<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4456according to the condition code given as <tt>cond</tt>.
4457If the operands are vectors, then the vectors are compared
4458element by element.
4459Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4460always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4461<ol>
4462 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4463 <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]4464 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4465 <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]4466 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4467 <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]4468 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4469 <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]4470 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4471 <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]4472 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4473 <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]4474 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4475 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4476 <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]4477 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4478 <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]4479 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4480 <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]4481 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4482 <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]4483 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4484 <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]4485 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4486 <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]4487 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4488 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4489 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4490</ol>
4491
4492<h5>Example:</h5>
4493<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]4494 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4495 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4496 &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]4497</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4498
4499<p>Note that the code generator does not yet support vector types with
4500 the <tt>fcmp</tt> instruction.</p>
4501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4502</div>
4503
4504<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4505<div class="doc_subsubsection">
4506 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4507</div>
4508<div class="doc_text">
4509<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4510<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]4511</pre>
4512<h5>Overview:</h5>
4513<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4514element-wise comparison of its two integer vector operands.</p>
4515<h5>Arguments:</h5>
4516<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4517the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4518a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4519<ol>
4520 <li><tt>eq</tt>: equal</li>
4521 <li><tt>ne</tt>: not equal </li>
4522 <li><tt>ugt</tt>: unsigned greater than</li>
4523 <li><tt>uge</tt>: unsigned greater or equal</li>
4524 <li><tt>ult</tt>: unsigned less than</li>
4525 <li><tt>ule</tt>: unsigned less or equal</li>
4526 <li><tt>sgt</tt>: signed greater than</li>
4527 <li><tt>sge</tt>: signed greater or equal</li>
4528 <li><tt>slt</tt>: signed less than</li>
4529 <li><tt>sle</tt>: signed less or equal</li>
4530</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4531<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4532<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4533<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4534<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4535according to the condition code given as <tt>cond</tt>. The comparison yields a
4536<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4537identical type as the values being compared. The most significant bit in each
4538element is 1 if the element-wise comparison evaluates to true, and is 0
4539otherwise. All other bits of the result are undefined. The condition codes
4540are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4541instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4542
4543<h5>Example:</h5>
4544<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4545 &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>
4546 &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]4547</pre>
4548</div>
4549
4550<!-- _______________________________________________________________________ -->
4551<div class="doc_subsubsection">
4552 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4553</div>
4554<div class="doc_text">
4555<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4556<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]4557<h5>Overview:</h5>
4558<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4559element-wise comparison of its two floating point vector operands. The output
4560elements have the same width as the input elements.</p>
4561<h5>Arguments:</h5>
4562<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4563the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4564a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4565<ol>
4566 <li><tt>false</tt>: no comparison, always returns false</li>
4567 <li><tt>oeq</tt>: ordered and equal</li>
4568 <li><tt>ogt</tt>: ordered and greater than </li>
4569 <li><tt>oge</tt>: ordered and greater than or equal</li>
4570 <li><tt>olt</tt>: ordered and less than </li>
4571 <li><tt>ole</tt>: ordered and less than or equal</li>
4572 <li><tt>one</tt>: ordered and not equal</li>
4573 <li><tt>ord</tt>: ordered (no nans)</li>
4574 <li><tt>ueq</tt>: unordered or equal</li>
4575 <li><tt>ugt</tt>: unordered or greater than </li>
4576 <li><tt>uge</tt>: unordered or greater than or equal</li>
4577 <li><tt>ult</tt>: unordered or less than </li>
4578 <li><tt>ule</tt>: unordered or less than or equal</li>
4579 <li><tt>une</tt>: unordered or not equal</li>
4580 <li><tt>uno</tt>: unordered (either nans)</li>
4581 <li><tt>true</tt>: no comparison, always returns true</li>
4582</ol>
4583<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4584<a href="#t_floating">floating point</a> typed. They must also be identical
4585types.</p>
4586<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4587<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4588according to the condition code given as <tt>cond</tt>. The comparison yields a
4589<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4590an identical number of elements as the values being compared, and each element
4591having identical with to the width of the floating point elements. The most
4592significant bit in each element is 1 if the element-wise comparison evaluates to
4593true, and is 0 otherwise. All other bits of the result are undefined. The
4594condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4595<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4596
4597<h5>Example:</h5>
4598<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4599 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4600 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4601
4602 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4603 &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]4604</pre>
4605</div>
4606
4607<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4608<div class="doc_subsubsection">
4609 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4610</div>
4611
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4612<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4613
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4614<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4615
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4616<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4617<h5>Overview:</h5>
4618<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4619the SSA graph representing the function.</p>
4620<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4621
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4622<p>The type of the incoming values is specified with the first type
4623field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4624as arguments, with one pair for each predecessor basic block of the
4625current block. Only values of <a href="#t_firstclass">first class</a>
4626type may be used as the value arguments to the PHI node. Only labels
4627may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4628
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4629<p>There must be no non-phi instructions between the start of a basic
4630block and the PHI instructions: i.e. PHI instructions must be first in
4631a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4632
Jay Foad8e2fd2c2009-06-03 10:20:10 +0000[diff] [blame]4633<p>For the purposes of the SSA form, the use of each incoming value is
4634deemed to occur on the edge from the corresponding predecessor block
4635to the current block (but after any definition of an '<tt>invoke</tt>'
4636instruction's return value on the same edge).</p>
4637
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4638<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4639
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4640<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4641specified by the pair corresponding to the predecessor basic block that executed
4642just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4643
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4644<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4645<pre>
4646Loop: ; Infinite loop that counts from 0 on up...
4647 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4648 %nextindvar = add i32 %indvar, 1
4649 br label %Loop
4650</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4651</div>
4652
4653<!-- _______________________________________________________________________ -->
4654<div class="doc_subsubsection">
4655 <a name="i_select">'<tt>select</tt>' Instruction</a>
4656</div>
4657
4658<div class="doc_text">
4659
4660<h5>Syntax:</h5>
4661
4662<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4663 &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>
4664
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4665 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666</pre>
4667
4668<h5>Overview:</h5>
4669
4670<p>
4671The '<tt>select</tt>' instruction is used to choose one value based on a
4672condition, without branching.
4673</p>
4674
4675
4676<h5>Arguments:</h5>
4677
4678<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4679The '<tt>select</tt>' instruction requires an 'i1' value or
4680a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4681condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4682type. If the val1/val2 are vectors and
4683the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4684individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4685</p>
4686
4687<h5>Semantics:</h5>
4688
4689<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4690If 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]4691value argument; otherwise, it returns the second value argument.
4692</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4693<p>
4694If the condition is a vector of i1, then the value arguments must
4695be vectors of the same size, and the selection is done element
4696by element.
4697</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4698
4699<h5>Example:</h5>
4700
4701<pre>
4702 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4703</pre>
Dan Gohmana53eb382009-01-22 01:39:38 +0000[diff] [blame]4704
4705<p>Note that the code generator does not yet support conditions
4706 with vector type.</p>
4707
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4708</div>
4709
4710
4711<!-- _______________________________________________________________________ -->
4712<div class="doc_subsubsection">
4713 <a name="i_call">'<tt>call</tt>' Instruction</a>
4714</div>
4715
4716<div class="doc_text">
4717
4718<h5>Syntax:</h5>
4719<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4720 &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]4721</pre>
4722
4723<h5>Overview:</h5>
4724
4725<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4726
4727<h5>Arguments:</h5>
4728
4729<p>This instruction requires several arguments:</p>
4730
4731<ol>
4732 <li>
4733 <p>The optional "tail" marker indicates whether the callee function accesses
4734 any allocas or varargs in the caller. If the "tail" marker is present, the
4735 function call is eligible for tail call optimization. Note that calls may
4736 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4737 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738 </li>
4739 <li>
4740 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4741 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4742 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4743 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4744
4745 <li>
4746 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4747 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4748 and '<tt>inreg</tt>' attributes are valid here.</p>
4749 </li>
4750
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4751 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4752 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4753 the type of the return value. Functions that return no value are marked
4754 <tt><a href="#t_void">void</a></tt>.</p>
4755 </li>
4756 <li>
4757 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4758 value being invoked. The argument types must match the types implied by
4759 this signature. This type can be omitted if the function is not varargs
4760 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4761 </li>
4762 <li>
4763 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4764 be invoked. In most cases, this is a direct function invocation, but
4765 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4766 to function value.</p>
4767 </li>
4768 <li>
4769 <p>'<tt>function args</tt>': argument list whose types match the
4770 function signature argument types. All arguments must be of
4771 <a href="#t_firstclass">first class</a> type. If the function signature
4772 indicates the function accepts a variable number of arguments, the extra
4773 arguments can be specified.</p>
4774 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4775 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4776 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4777 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4778 '<tt>readnone</tt>' attributes are valid here.</p>
4779 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4780</ol>
4781
4782<h5>Semantics:</h5>
4783
4784<p>The '<tt>call</tt>' instruction is used to cause control flow to
4785transfer to a specified function, with its incoming arguments bound to
4786the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4787instruction in the called function, control flow continues with the
4788instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4789function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4790
4791<h5>Example:</h5>
4792
4793<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4794 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4795 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4796 %X = tail call i32 @foo() <i>; yields i32</i>
4797 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4798 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4799
4800 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4801 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4802 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4803 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4804 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4805 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4806</pre>
4807
4808</div>
4809
4810<!-- _______________________________________________________________________ -->
4811<div class="doc_subsubsection">
4812 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4813</div>
4814
4815<div class="doc_text">
4816
4817<h5>Syntax:</h5>
4818
4819<pre>
4820 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4821</pre>
4822
4823<h5>Overview:</h5>
4824
4825<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4826the "variable argument" area of a function call. It is used to implement the
4827<tt>va_arg</tt> macro in C.</p>
4828
4829<h5>Arguments:</h5>
4830
4831<p>This instruction takes a <tt>va_list*</tt> value and the type of
4832the argument. It returns a value of the specified argument type and
4833increments the <tt>va_list</tt> to point to the next argument. The
4834actual type of <tt>va_list</tt> is target specific.</p>
4835
4836<h5>Semantics:</h5>
4837
4838<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4839type from the specified <tt>va_list</tt> and causes the
4840<tt>va_list</tt> to point to the next argument. For more information,
4841see the variable argument handling <a href="#int_varargs">Intrinsic
4842Functions</a>.</p>
4843
4844<p>It is legal for this instruction to be called in a function which does not
4845take a variable number of arguments, for example, the <tt>vfprintf</tt>
4846function.</p>
4847
4848<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4849href="#intrinsics">intrinsic function</a> because it takes a type as an
4850argument.</p>
4851
4852<h5>Example:</h5>
4853
4854<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4855
Dan Gohman60967192009-01-12 23:12:39 +0000[diff] [blame]4856<p>Note that the code generator does not yet fully support va_arg
4857 on many targets. Also, it does not currently support va_arg with
4858 aggregate types on any target.</p>
4859
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4860</div>
4861
4862<!-- *********************************************************************** -->
4863<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4864<!-- *********************************************************************** -->
4865
4866<div class="doc_text">
4867
4868<p>LLVM supports the notion of an "intrinsic function". These functions have
4869well known names and semantics and are required to follow certain restrictions.
4870Overall, these intrinsics represent an extension mechanism for the LLVM
4871language that does not require changing all of the transformations in LLVM when
4872adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4873
4874<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4875prefix is reserved in LLVM for intrinsic names; thus, function names may not
4876begin with this prefix. Intrinsic functions must always be external functions:
4877you cannot define the body of intrinsic functions. Intrinsic functions may
4878only be used in call or invoke instructions: it is illegal to take the address
4879of an intrinsic function. Additionally, because intrinsic functions are part
4880of the LLVM language, it is required if any are added that they be documented
4881here.</p>
4882
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4883<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4884a family of functions that perform the same operation but on different data
4885types. Because LLVM can represent over 8 million different integer types,
4886overloading is used commonly to allow an intrinsic function to operate on any
4887integer type. One or more of the argument types or the result type can be
4888overloaded to accept any integer type. Argument types may also be defined as
4889exactly matching a previous argument's type or the result type. This allows an
4890intrinsic function which accepts multiple arguments, but needs all of them to
4891be of the same type, to only be overloaded with respect to a single argument or
4892the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4893
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4894<p>Overloaded intrinsics will have the names of its overloaded argument types
4895encoded into its function name, each preceded by a period. Only those types
4896which are overloaded result in a name suffix. Arguments whose type is matched
4897against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4898take an integer of any width and returns an integer of exactly the same integer
4899width. This leads to a family of functions such as
4900<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4901Only one type, the return type, is overloaded, and only one type suffix is
4902required. Because the argument's type is matched against the return type, it
4903does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4904
4905<p>To learn how to add an intrinsic function, please see the
4906<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4907</p>
4908
4909</div>
4910
4911<!-- ======================================================================= -->
4912<div class="doc_subsection">
4913 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4914</div>
4915
4916<div class="doc_text">
4917
4918<p>Variable argument support is defined in LLVM with the <a
4919 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4920intrinsic functions. These functions are related to the similarly
4921named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4922
4923<p>All of these functions operate on arguments that use a
4924target-specific value type "<tt>va_list</tt>". The LLVM assembly
4925language reference manual does not define what this type is, so all
4926transformations should be prepared to handle these functions regardless of
4927the type used.</p>
4928
4929<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4930instruction and the variable argument handling intrinsic functions are
4931used.</p>
4932
4933<div class="doc_code">
4934<pre>
4935define i32 @test(i32 %X, ...) {
4936 ; Initialize variable argument processing
4937 %ap = alloca i8*
4938 %ap2 = bitcast i8** %ap to i8*
4939 call void @llvm.va_start(i8* %ap2)
4940
4941 ; Read a single integer argument
4942 %tmp = va_arg i8** %ap, i32
4943
4944 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4945 %aq = alloca i8*
4946 %aq2 = bitcast i8** %aq to i8*
4947 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4948 call void @llvm.va_end(i8* %aq2)
4949
4950 ; Stop processing of arguments.
4951 call void @llvm.va_end(i8* %ap2)
4952 ret i32 %tmp
4953}
4954
4955declare void @llvm.va_start(i8*)
4956declare void @llvm.va_copy(i8*, i8*)
4957declare void @llvm.va_end(i8*)
4958</pre>
4959</div>
4960
4961</div>
4962
4963<!-- _______________________________________________________________________ -->
4964<div class="doc_subsubsection">
4965 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4966</div>
4967
4968
4969<div class="doc_text">
4970<h5>Syntax:</h5>
4971<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4972<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4973<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4974<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4975href="#i_va_arg">va_arg</a></tt>.</p>
4976
4977<h5>Arguments:</h5>
4978
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4979<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]4980
4981<h5>Semantics:</h5>
4982
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4983<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]4984macro available in C. In a target-dependent way, it initializes the
4985<tt>va_list</tt> element to which the argument points, so that the next call to
4986<tt>va_arg</tt> will produce the first variable argument passed to the function.
4987Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4988last argument of the function as the compiler can figure that out.</p>
4989
4990</div>
4991
4992<!-- _______________________________________________________________________ -->
4993<div class="doc_subsubsection">
4994 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4995</div>
4996
4997<div class="doc_text">
4998<h5>Syntax:</h5>
4999<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
5000<h5>Overview:</h5>
5001
5002<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
5003which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
5004or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
5005
5006<h5>Arguments:</h5>
5007
5008<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
5009
5010<h5>Semantics:</h5>
5011
5012<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
5013macro available in C. In a target-dependent way, it destroys the
5014<tt>va_list</tt> element to which the argument points. Calls to <a
5015href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
5016<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
5017<tt>llvm.va_end</tt>.</p>
5018
5019</div>
5020
5021<!-- _______________________________________________________________________ -->
5022<div class="doc_subsubsection">
5023 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
5024</div>
5025
5026<div class="doc_text">
5027
5028<h5>Syntax:</h5>
5029
5030<pre>
5031 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
5032</pre>
5033
5034<h5>Overview:</h5>
5035
5036<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
5037from the source argument list to the destination argument list.</p>
5038
5039<h5>Arguments:</h5>
5040
5041<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
5042The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
5043
5044
5045<h5>Semantics:</h5>
5046
5047<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
5048macro available in C. In a target-dependent way, it copies the source
5049<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
5050intrinsic is necessary because the <tt><a href="#int_va_start">
5051llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
5052example, memory allocation.</p>
5053
5054</div>
5055
5056<!-- ======================================================================= -->
5057<div class="doc_subsection">
5058 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
5059</div>
5060
5061<div class="doc_text">
5062
5063<p>
5064LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5065Collection</a> (GC) requires the implementation and generation of these
5066intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5067These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
5068stack</a>, as well as garbage collector implementations that require <a
5069href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
5070Front-ends for type-safe garbage collected languages should generate these
5071intrinsics to make use of the LLVM garbage collectors. For more details, see <a
5072href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
5073</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]5074
5075<p>The garbage collection intrinsics only operate on objects in the generic
5076 address space (address space zero).</p>
5077
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5078</div>
5079
5080<!-- _______________________________________________________________________ -->
5081<div class="doc_subsubsection">
5082 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
5083</div>
5084
5085<div class="doc_text">
5086
5087<h5>Syntax:</h5>
5088
5089<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5090 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5091</pre>
5092
5093<h5>Overview:</h5>
5094
5095<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
5096the code generator, and allows some metadata to be associated with it.</p>
5097
5098<h5>Arguments:</h5>
5099
5100<p>The first argument specifies the address of a stack object that contains the
5101root pointer. The second pointer (which must be either a constant or a global
5102value address) contains the meta-data to be associated with the root.</p>
5103
5104<h5>Semantics:</h5>
5105
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]5106<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]5107location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5108the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
5109intrinsic may only be used in a function which <a href="#gc">specifies a GC
5110algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5111
5112</div>
5113
5114
5115<!-- _______________________________________________________________________ -->
5116<div class="doc_subsubsection">
5117 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
5118</div>
5119
5120<div class="doc_text">
5121
5122<h5>Syntax:</h5>
5123
5124<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5125 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5126</pre>
5127
5128<h5>Overview:</h5>
5129
5130<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
5131locations, allowing garbage collector implementations that require read
5132barriers.</p>
5133
5134<h5>Arguments:</h5>
5135
5136<p>The second argument is the address to read from, which should be an address
5137allocated from the garbage collector. The first object is a pointer to the
5138start of the referenced object, if needed by the language runtime (otherwise
5139null).</p>
5140
5141<h5>Semantics:</h5>
5142
5143<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
5144instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5145garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
5146may only be used in a function which <a href="#gc">specifies a GC
5147algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5148
5149</div>
5150
5151
5152<!-- _______________________________________________________________________ -->
5153<div class="doc_subsubsection">
5154 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
5155</div>
5156
5157<div class="doc_text">
5158
5159<h5>Syntax:</h5>
5160
5161<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5162 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5163</pre>
5164
5165<h5>Overview:</h5>
5166
5167<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5168locations, allowing garbage collector implementations that require write
5169barriers (such as generational or reference counting collectors).</p>
5170
5171<h5>Arguments:</h5>
5172
5173<p>The first argument is the reference to store, the second is the start of the
5174object to store it to, and the third is the address of the field of Obj to
5175store to. If the runtime does not require a pointer to the object, Obj may be
5176null.</p>
5177
5178<h5>Semantics:</h5>
5179
5180<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5181instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]5182garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5183may only be used in a function which <a href="#gc">specifies a GC
5184algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5185
5186</div>
5187
5188
5189
5190<!-- ======================================================================= -->
5191<div class="doc_subsection">
5192 <a name="int_codegen">Code Generator Intrinsics</a>
5193</div>
5194
5195<div class="doc_text">
5196<p>
5197These intrinsics are provided by LLVM to expose special features that may only
5198be implemented with code generator support.
5199</p>
5200
5201</div>
5202
5203<!-- _______________________________________________________________________ -->
5204<div class="doc_subsubsection">
5205 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
5206</div>
5207
5208<div class="doc_text">
5209
5210<h5>Syntax:</h5>
5211<pre>
5212 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
5213</pre>
5214
5215<h5>Overview:</h5>
5216
5217<p>
5218The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5219target-specific value indicating the return address of the current function
5220or one of its callers.
5221</p>
5222
5223<h5>Arguments:</h5>
5224
5225<p>
5226The argument to this intrinsic indicates which function to return the address
5227for. Zero indicates the calling function, one indicates its caller, etc. The
5228argument is <b>required</b> to be a constant integer value.
5229</p>
5230
5231<h5>Semantics:</h5>
5232
5233<p>
5234The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5235the return address of the specified call frame, or zero if it cannot be
5236identified. The value returned by this intrinsic is likely to be incorrect or 0
5237for arguments other than zero, so it should only be used for debugging purposes.
5238</p>
5239
5240<p>
5241Note that calling this intrinsic does not prevent function inlining or other
5242aggressive transformations, so the value returned may not be that of the obvious
5243source-language caller.
5244</p>
5245</div>
5246
5247
5248<!-- _______________________________________________________________________ -->
5249<div class="doc_subsubsection">
5250 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
5251</div>
5252
5253<div class="doc_text">
5254
5255<h5>Syntax:</h5>
5256<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5257 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5258</pre>
5259
5260<h5>Overview:</h5>
5261
5262<p>
5263The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5264target-specific frame pointer value for the specified stack frame.
5265</p>
5266
5267<h5>Arguments:</h5>
5268
5269<p>
5270The argument to this intrinsic indicates which function to return the frame
5271pointer for. Zero indicates the calling function, one indicates its caller,
5272etc. The argument is <b>required</b> to be a constant integer value.
5273</p>
5274
5275<h5>Semantics:</h5>
5276
5277<p>
5278The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5279the frame address of the specified call frame, or zero if it cannot be
5280identified. The value returned by this intrinsic is likely to be incorrect or 0
5281for arguments other than zero, so it should only be used for debugging purposes.
5282</p>
5283
5284<p>
5285Note that calling this intrinsic does not prevent function inlining or other
5286aggressive transformations, so the value returned may not be that of the obvious
5287source-language caller.
5288</p>
5289</div>
5290
5291<!-- _______________________________________________________________________ -->
5292<div class="doc_subsubsection">
5293 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
5294</div>
5295
5296<div class="doc_text">
5297
5298<h5>Syntax:</h5>
5299<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5300 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5301</pre>
5302
5303<h5>Overview:</h5>
5304
5305<p>
5306The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
5307the function stack, for use with <a href="#int_stackrestore">
5308<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5309features like scoped automatic variable sized arrays in C99.
5310</p>
5311
5312<h5>Semantics:</h5>
5313
5314<p>
5315This intrinsic returns a opaque pointer value that can be passed to <a
5316href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
5317<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5318<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5319state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5320practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5321that were allocated after the <tt>llvm.stacksave</tt> was executed.
5322</p>
5323
5324</div>
5325
5326<!-- _______________________________________________________________________ -->
5327<div class="doc_subsubsection">
5328 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
5329</div>
5330
5331<div class="doc_text">
5332
5333<h5>Syntax:</h5>
5334<pre>
5335 declare void @llvm.stackrestore(i8 * %ptr)
5336</pre>
5337
5338<h5>Overview:</h5>
5339
5340<p>
5341The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5342the function stack to the state it was in when the corresponding <a
5343href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
5344useful for implementing language features like scoped automatic variable sized
5345arrays in C99.
5346</p>
5347
5348<h5>Semantics:</h5>
5349
5350<p>
5351See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
5352</p>
5353
5354</div>
5355
5356
5357<!-- _______________________________________________________________________ -->
5358<div class="doc_subsubsection">
5359 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
5360</div>
5361
5362<div class="doc_text">
5363
5364<h5>Syntax:</h5>
5365<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5366 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]5367</pre>
5368
5369<h5>Overview:</h5>
5370
5371
5372<p>
5373The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
5374a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5375no
5376effect on the behavior of the program but can change its performance
5377characteristics.
5378</p>
5379
5380<h5>Arguments:</h5>
5381
5382<p>
5383<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5384determining if the fetch should be for a read (0) or write (1), and
5385<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
5386locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
5387<tt>locality</tt> arguments must be constant integers.
5388</p>
5389
5390<h5>Semantics:</h5>
5391
5392<p>
5393This intrinsic does not modify the behavior of the program. In particular,
5394prefetches cannot trap and do not produce a value. On targets that support this
5395intrinsic, the prefetch can provide hints to the processor cache for better
5396performance.
5397</p>
5398
5399</div>
5400
5401<!-- _______________________________________________________________________ -->
5402<div class="doc_subsubsection">
5403 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5404</div>
5405
5406<div class="doc_text">
5407
5408<h5>Syntax:</h5>
5409<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5410 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5411</pre>
5412
5413<h5>Overview:</h5>
5414
5415
5416<p>
5417The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5418(PC) in a region of
5419code to simulators and other tools. The method is target specific, but it is
5420expected that the marker will use exported symbols to transmit the PC of the
5421marker.
5422The marker makes no guarantees that it will remain with any specific instruction
5423after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5424optimizations. The intended use is to be inserted after optimizations to allow
5425correlations of simulation runs.
5426</p>
5427
5428<h5>Arguments:</h5>
5429
5430<p>
5431<tt>id</tt> is a numerical id identifying the marker.
5432</p>
5433
5434<h5>Semantics:</h5>
5435
5436<p>
5437This intrinsic does not modify the behavior of the program. Backends that do not
5438support this intrinisic may ignore it.
5439</p>
5440
5441</div>
5442
5443<!-- _______________________________________________________________________ -->
5444<div class="doc_subsubsection">
5445 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5446</div>
5447
5448<div class="doc_text">
5449
5450<h5>Syntax:</h5>
5451<pre>
5452 declare i64 @llvm.readcyclecounter( )
5453</pre>
5454
5455<h5>Overview:</h5>
5456
5457
5458<p>
5459The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5460counter register (or similar low latency, high accuracy clocks) on those targets
5461that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5462As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5463should only be used for small timings.
5464</p>
5465
5466<h5>Semantics:</h5>
5467
5468<p>
5469When directly supported, reading the cycle counter should not modify any memory.
5470Implementations are allowed to either return a application specific value or a
5471system wide value. On backends without support, this is lowered to a constant 0.
5472</p>
5473
5474</div>
5475
5476<!-- ======================================================================= -->
5477<div class="doc_subsection">
5478 <a name="int_libc">Standard C Library Intrinsics</a>
5479</div>
5480
5481<div class="doc_text">
5482<p>
5483LLVM provides intrinsics for a few important standard C library functions.
5484These intrinsics allow source-language front-ends to pass information about the
5485alignment of the pointer arguments to the code generator, providing opportunity
5486for more efficient code generation.
5487</p>
5488
5489</div>
5490
5491<!-- _______________________________________________________________________ -->
5492<div class="doc_subsubsection">
5493 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5494</div>
5495
5496<div class="doc_text">
5497
5498<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5499<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5500width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5501<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5502 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5503 i8 &lt;len&gt;, i32 &lt;align&gt;)
5504 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5505 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5506 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5507 i32 &lt;len&gt;, i32 &lt;align&gt;)
5508 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5509 i64 &lt;len&gt;, i32 &lt;align&gt;)
5510</pre>
5511
5512<h5>Overview:</h5>
5513
5514<p>
5515The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5516location to the destination location.
5517</p>
5518
5519<p>
5520Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5521intrinsics do not return a value, and takes an extra alignment argument.
5522</p>
5523
5524<h5>Arguments:</h5>
5525
5526<p>
5527The first argument is a pointer to the destination, the second is a pointer to
5528the source. The third argument is an integer argument
5529specifying the number of bytes to copy, and the fourth argument is the alignment
5530of the source and destination locations.
5531</p>
5532
5533<p>
5534If the call to this intrinisic has an alignment value that is not 0 or 1, then
5535the caller guarantees that both the source and destination pointers are aligned
5536to that boundary.
5537</p>
5538
5539<h5>Semantics:</h5>
5540
5541<p>
5542The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5543location to the destination location, which are not allowed to overlap. It
5544copies "len" bytes of memory over. If the argument is known to be aligned to
5545some boundary, this can be specified as the fourth argument, otherwise it should
5546be set to 0 or 1.
5547</p>
5548</div>
5549
5550
5551<!-- _______________________________________________________________________ -->
5552<div class="doc_subsubsection">
5553 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5554</div>
5555
5556<div class="doc_text">
5557
5558<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5559<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5560width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5561<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5562 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5563 i8 &lt;len&gt;, i32 &lt;align&gt;)
5564 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5565 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5566 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5567 i32 &lt;len&gt;, i32 &lt;align&gt;)
5568 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5569 i64 &lt;len&gt;, i32 &lt;align&gt;)
5570</pre>
5571
5572<h5>Overview:</h5>
5573
5574<p>
5575The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5576location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5577'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5578</p>
5579
5580<p>
5581Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5582intrinsics do not return a value, and takes an extra alignment argument.
5583</p>
5584
5585<h5>Arguments:</h5>
5586
5587<p>
5588The first argument is a pointer to the destination, the second is a pointer to
5589the source. The third argument is an integer argument
5590specifying the number of bytes to copy, and the fourth argument is the alignment
5591of the source and destination locations.
5592</p>
5593
5594<p>
5595If the call to this intrinisic has an alignment value that is not 0 or 1, then
5596the caller guarantees that the source and destination pointers are aligned to
5597that boundary.
5598</p>
5599
5600<h5>Semantics:</h5>
5601
5602<p>
5603The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5604location to the destination location, which may overlap. It
5605copies "len" bytes of memory over. If the argument is known to be aligned to
5606some boundary, this can be specified as the fourth argument, otherwise it should
5607be set to 0 or 1.
5608</p>
5609</div>
5610
5611
5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
5614 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5620<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5621width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5623 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5624 i8 &lt;len&gt;, i32 &lt;align&gt;)
5625 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5626 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5627 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5628 i32 &lt;len&gt;, i32 &lt;align&gt;)
5629 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5630 i64 &lt;len&gt;, i32 &lt;align&gt;)
5631</pre>
5632
5633<h5>Overview:</h5>
5634
5635<p>
5636The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5637byte value.
5638</p>
5639
5640<p>
5641Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5642does not return a value, and takes an extra alignment argument.
5643</p>
5644
5645<h5>Arguments:</h5>
5646
5647<p>
5648The first argument is a pointer to the destination to fill, the second is the
5649byte value to fill it with, the third argument is an integer
5650argument specifying the number of bytes to fill, and the fourth argument is the
5651known alignment of destination location.
5652</p>
5653
5654<p>
5655If the call to this intrinisic has an alignment value that is not 0 or 1, then
5656the caller guarantees that the destination pointer is aligned to that boundary.
5657</p>
5658
5659<h5>Semantics:</h5>
5660
5661<p>
5662The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5663the
5664destination location. If the argument is known to be aligned to some boundary,
5665this can be specified as the fourth argument, otherwise it should be set to 0 or
56661.
5667</p>
5668</div>
5669
5670
5671<!-- _______________________________________________________________________ -->
5672<div class="doc_subsubsection">
5673 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5674</div>
5675
5676<div class="doc_text">
5677
5678<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5679<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]5680floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5681types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5682<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5683 declare float @llvm.sqrt.f32(float %Val)
5684 declare double @llvm.sqrt.f64(double %Val)
5685 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5686 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5687 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5688</pre>
5689
5690<h5>Overview:</h5>
5691
5692<p>
5693The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5694returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5695<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5696negative numbers other than -0.0 (which allows for better optimization, because
5697there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5698defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5699</p>
5700
5701<h5>Arguments:</h5>
5702
5703<p>
5704The argument and return value are floating point numbers of the same type.
5705</p>
5706
5707<h5>Semantics:</h5>
5708
5709<p>
5710This function returns the sqrt of the specified operand if it is a nonnegative
5711floating point number.
5712</p>
5713</div>
5714
5715<!-- _______________________________________________________________________ -->
5716<div class="doc_subsubsection">
5717 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5718</div>
5719
5720<div class="doc_text">
5721
5722<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5723<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]5724floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5725types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5726<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5727 declare float @llvm.powi.f32(float %Val, i32 %power)
5728 declare double @llvm.powi.f64(double %Val, i32 %power)
5729 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5730 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5731 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5732</pre>
5733
5734<h5>Overview:</h5>
5735
5736<p>
5737The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5738specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5739multiplications is not defined. When a vector of floating point type is
5740used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5741</p>
5742
5743<h5>Arguments:</h5>
5744
5745<p>
5746The second argument is an integer power, and the first is a value to raise to
5747that power.
5748</p>
5749
5750<h5>Semantics:</h5>
5751
5752<p>
5753This function returns the first value raised to the second power with an
5754unspecified sequence of rounding operations.</p>
5755</div>
5756
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5757<!-- _______________________________________________________________________ -->
5758<div class="doc_subsubsection">
5759 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5760</div>
5761
5762<div class="doc_text">
5763
5764<h5>Syntax:</h5>
5765<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5766floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5767types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5768<pre>
5769 declare float @llvm.sin.f32(float %Val)
5770 declare double @llvm.sin.f64(double %Val)
5771 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5772 declare fp128 @llvm.sin.f128(fp128 %Val)
5773 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5774</pre>
5775
5776<h5>Overview:</h5>
5777
5778<p>
5779The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5780</p>
5781
5782<h5>Arguments:</h5>
5783
5784<p>
5785The argument and return value are floating point numbers of the same type.
5786</p>
5787
5788<h5>Semantics:</h5>
5789
5790<p>
5791This function returns the sine of the specified operand, returning the
5792same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5793conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5794</div>
5795
5796<!-- _______________________________________________________________________ -->
5797<div class="doc_subsubsection">
5798 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5799</div>
5800
5801<div class="doc_text">
5802
5803<h5>Syntax:</h5>
5804<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5805floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5806types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5807<pre>
5808 declare float @llvm.cos.f32(float %Val)
5809 declare double @llvm.cos.f64(double %Val)
5810 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5811 declare fp128 @llvm.cos.f128(fp128 %Val)
5812 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5813</pre>
5814
5815<h5>Overview:</h5>
5816
5817<p>
5818The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5819</p>
5820
5821<h5>Arguments:</h5>
5822
5823<p>
5824The argument and return value are floating point numbers of the same type.
5825</p>
5826
5827<h5>Semantics:</h5>
5828
5829<p>
5830This function returns the cosine of the specified operand, returning the
5831same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5832conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5833</div>
5834
5835<!-- _______________________________________________________________________ -->
5836<div class="doc_subsubsection">
5837 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5838</div>
5839
5840<div class="doc_text">
5841
5842<h5>Syntax:</h5>
5843<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5844floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5845types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5846<pre>
5847 declare float @llvm.pow.f32(float %Val, float %Power)
5848 declare double @llvm.pow.f64(double %Val, double %Power)
5849 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5850 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5851 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5852</pre>
5853
5854<h5>Overview:</h5>
5855
5856<p>
5857The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5858specified (positive or negative) power.
5859</p>
5860
5861<h5>Arguments:</h5>
5862
5863<p>
5864The second argument is a floating point power, and the first is a value to
5865raise to that power.
5866</p>
5867
5868<h5>Semantics:</h5>
5869
5870<p>
5871This function returns the first value raised to the second power,
5872returning the
5873same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5874conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5875</div>
5876
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5877
5878<!-- ======================================================================= -->
5879<div class="doc_subsection">
5880 <a name="int_manip">Bit Manipulation Intrinsics</a>
5881</div>
5882
5883<div class="doc_text">
5884<p>
5885LLVM provides intrinsics for a few important bit manipulation operations.
5886These allow efficient code generation for some algorithms.
5887</p>
5888
5889</div>
5890
5891<!-- _______________________________________________________________________ -->
5892<div class="doc_subsubsection">
5893 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5894</div>
5895
5896<div class="doc_text">
5897
5898<h5>Syntax:</h5>
5899<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5900type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5901<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5902 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5903 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5904 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5905</pre>
5906
5907<h5>Overview:</h5>
5908
5909<p>
5910The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5911values with an even number of bytes (positive multiple of 16 bits). These are
5912useful for performing operations on data that is not in the target's native
5913byte order.
5914</p>
5915
5916<h5>Semantics:</h5>
5917
5918<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5919The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5920and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5921intrinsic returns an i32 value that has the four bytes of the input i32
5922swapped, 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]5923i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5924<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5925additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5926</p>
5927
5928</div>
5929
5930<!-- _______________________________________________________________________ -->
5931<div class="doc_subsubsection">
5932 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5933</div>
5934
5935<div class="doc_text">
5936
5937<h5>Syntax:</h5>
5938<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]5939width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5940<pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]5941 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5942 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5943 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5944 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5945 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5946</pre>
5947
5948<h5>Overview:</h5>
5949
5950<p>
5951The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5952value.
5953</p>
5954
5955<h5>Arguments:</h5>
5956
5957<p>
5958The only argument is the value to be counted. The argument may be of any
5959integer type. The return type must match the argument type.
5960</p>
5961
5962<h5>Semantics:</h5>
5963
5964<p>
5965The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5966</p>
5967</div>
5968
5969<!-- _______________________________________________________________________ -->
5970<div class="doc_subsubsection">
5971 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5972</div>
5973
5974<div class="doc_text">
5975
5976<h5>Syntax:</h5>
5977<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]5978integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5979<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5980 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5981 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5982 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5983 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5984 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5985</pre>
5986
5987<h5>Overview:</h5>
5988
5989<p>
5990The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5991leading zeros in a variable.
5992</p>
5993
5994<h5>Arguments:</h5>
5995
5996<p>
5997The only argument is the value to be counted. The argument may be of any
5998integer type. The return type must match the argument type.
5999</p>
6000
6001<h5>Semantics:</h5>
6002
6003<p>
6004The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
6005in a variable. If the src == 0 then the result is the size in bits of the type
6006of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
6007</p>
6008</div>
6009
6010
6011
6012<!-- _______________________________________________________________________ -->
6013<div class="doc_subsubsection">
6014 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
6015</div>
6016
6017<div class="doc_text">
6018
6019<h5>Syntax:</h5>
6020<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]6021integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6022<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6023 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
6024 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6025 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6026 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
6027 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6028</pre>
6029
6030<h5>Overview:</h5>
6031
6032<p>
6033The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
6034trailing zeros.
6035</p>
6036
6037<h5>Arguments:</h5>
6038
6039<p>
6040The only argument is the value to be counted. The argument may be of any
6041integer type. The return type must match the argument type.
6042</p>
6043
6044<h5>Semantics:</h5>
6045
6046<p>
6047The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
6048in a variable. If the src == 0 then the result is the size in bits of the type
6049of src. For example, <tt>llvm.cttz(2) = 1</tt>.
6050</p>
6051</div>
6052
6053<!-- _______________________________________________________________________ -->
6054<div class="doc_subsubsection">
6055 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
6056</div>
6057
6058<div class="doc_text">
6059
6060<h5>Syntax:</h5>
6061<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6062on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6063<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6064 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
6065 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6066</pre>
6067
6068<h5>Overview:</h5>
6069<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
6070range of bits from an integer value and returns them in the same bit width as
6071the original value.</p>
6072
6073<h5>Arguments:</h5>
6074<p>The first argument, <tt>%val</tt> and the result may be integer types of
6075any bit width but they must have the same bit width. The second and third
6076arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
6077
6078<h5>Semantics:</h5>
6079<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
6080of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
6081<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
6082operates in forward mode.</p>
6083<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
6084right by <tt>%loBit</tt> bits and then ANDing it with a mask with
6085only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
6086<ol>
6087 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
6088 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
6089 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
6090 to determine the number of bits to retain.</li>
6091 <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]6092 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6093</ol>
6094<p>In reverse mode, a similar computation is made except that the bits are
6095returned in the reverse order. So, for example, if <tt>X</tt> has the value
6096<tt>i16 0x0ACF (101011001111)</tt> and we apply
6097<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
6098<tt>i16 0x0026 (000000100110)</tt>.</p>
6099</div>
6100
6101<div class="doc_subsubsection">
6102 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
6103</div>
6104
6105<div class="doc_text">
6106
6107<h5>Syntax:</h5>
6108<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6109on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6110<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]6111 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
6112 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]6113</pre>
6114
6115<h5>Overview:</h5>
6116<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
6117of bits in an integer value with another integer value. It returns the integer
6118with the replaced bits.</p>
6119
6120<h5>Arguments:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6121<p>The first argument, <tt>%val</tt>, and the result may be integer types of
6122any 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]6123whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
6124integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
6125type since they specify only a bit index.</p>
6126
6127<h5>Semantics:</h5>
6128<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
6129of operation: forwards and reverse. If <tt>%lo</tt> is greater than
6130<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
6131operates in forward mode.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6132
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6133<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
6134truncating it down to the size of the replacement area or zero extending it
6135up to that size.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6136
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6137<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
6138are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
6139in <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]6140to the <tt>%hi</tt>th bit.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6141
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6142<p>In reverse mode, a similar computation is made except that the bits are
6143reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6144<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]6145
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6146<h5>Examples:</h5>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6147
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6148<pre>
6149 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
6150 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
6151 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
6152 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
6153 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
6154</pre>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6155
6156</div>
6157
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6158<!-- ======================================================================= -->
6159<div class="doc_subsection">
6160 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6161</div>
6162
6163<div class="doc_text">
6164<p>
6165LLVM provides intrinsics for some arithmetic with overflow operations.
6166</p>
6167
6168</div>
6169
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6170<!-- _______________________________________________________________________ -->
6171<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6172 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6173</div>
6174
6175<div class="doc_text">
6176
6177<h5>Syntax:</h5>
6178
6179<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]6180on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6181
6182<pre>
6183 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6184 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6185 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6186</pre>
6187
6188<h5>Overview:</h5>
6189
6190<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6191a signed addition of the two arguments, and indicate whether an overflow
6192occurred during the signed summation.</p>
6193
6194<h5>Arguments:</h5>
6195
6196<p>The arguments (%a and %b) and the first element of the result structure may
6197be of integer types of any bit width, but they must have the same bit width. The
6198second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6199and <tt>%b</tt> are the two values that will undergo signed addition.</p>
6200
6201<h5>Semantics:</h5>
6202
6203<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6204a signed addition of the two variables. They return a structure &mdash; the
6205first element of which is the signed summation, and the second element of which
6206is a bit specifying if the signed summation resulted in an overflow.</p>
6207
6208<h5>Examples:</h5>
6209<pre>
6210 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6211 %sum = extractvalue {i32, i1} %res, 0
6212 %obit = extractvalue {i32, i1} %res, 1
6213 br i1 %obit, label %overflow, label %normal
6214</pre>
6215
6216</div>
6217
6218<!-- _______________________________________________________________________ -->
6219<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6220 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6221</div>
6222
6223<div class="doc_text">
6224
6225<h5>Syntax:</h5>
6226
6227<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]6228on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6229
6230<pre>
6231 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6232 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6233 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6234</pre>
6235
6236<h5>Overview:</h5>
6237
6238<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6239an unsigned addition of the two arguments, and indicate whether a carry occurred
6240during the unsigned summation.</p>
6241
6242<h5>Arguments:</h5>
6243
6244<p>The arguments (%a and %b) and the first element of the result structure may
6245be of integer types of any bit width, but they must have the same bit width. The
6246second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6247and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6248
6249<h5>Semantics:</h5>
6250
6251<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6252an unsigned addition of the two arguments. They return a structure &mdash; the
6253first element of which is the sum, and the second element of which is a bit
6254specifying if the unsigned summation resulted in a carry.</p>
6255
6256<h5>Examples:</h5>
6257<pre>
6258 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6259 %sum = extractvalue {i32, i1} %res, 0
6260 %obit = extractvalue {i32, i1} %res, 1
6261 br i1 %obit, label %carry, label %normal
6262</pre>
6263
6264</div>
6265
6266<!-- _______________________________________________________________________ -->
6267<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6268 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6269</div>
6270
6271<div class="doc_text">
6272
6273<h5>Syntax:</h5>
6274
6275<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]6276on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6277
6278<pre>
6279 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6280 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6281 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6282</pre>
6283
6284<h5>Overview:</h5>
6285
6286<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6287a signed subtraction of the two arguments, and indicate whether an overflow
6288occurred during the signed subtraction.</p>
6289
6290<h5>Arguments:</h5>
6291
6292<p>The arguments (%a and %b) and the first element of the result structure may
6293be of integer types of any bit width, but they must have the same bit width. The
6294second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6295and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6296
6297<h5>Semantics:</h5>
6298
6299<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6300a signed subtraction of the two arguments. They return a structure &mdash; the
6301first element of which is the subtraction, and the second element of which is a bit
6302specifying if the signed subtraction resulted in an overflow.</p>
6303
6304<h5>Examples:</h5>
6305<pre>
6306 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6307 %sum = extractvalue {i32, i1} %res, 0
6308 %obit = extractvalue {i32, i1} %res, 1
6309 br i1 %obit, label %overflow, label %normal
6310</pre>
6311
6312</div>
6313
6314<!-- _______________________________________________________________________ -->
6315<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6316 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6317</div>
6318
6319<div class="doc_text">
6320
6321<h5>Syntax:</h5>
6322
6323<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]6324on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6325
6326<pre>
6327 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6328 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6329 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6330</pre>
6331
6332<h5>Overview:</h5>
6333
6334<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6335an unsigned subtraction of the two arguments, and indicate whether an overflow
6336occurred during the unsigned subtraction.</p>
6337
6338<h5>Arguments:</h5>
6339
6340<p>The arguments (%a and %b) and the first element of the result structure may
6341be of integer types of any bit width, but they must have the same bit width. The
6342second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6343and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6344
6345<h5>Semantics:</h5>
6346
6347<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6348an unsigned subtraction of the two arguments. They return a structure &mdash; the
6349first element of which is the subtraction, and the second element of which is a bit
6350specifying if the unsigned subtraction resulted in an overflow.</p>
6351
6352<h5>Examples:</h5>
6353<pre>
6354 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6355 %sum = extractvalue {i32, i1} %res, 0
6356 %obit = extractvalue {i32, i1} %res, 1
6357 br i1 %obit, label %overflow, label %normal
6358</pre>
6359
6360</div>
6361
6362<!-- _______________________________________________________________________ -->
6363<div class="doc_subsubsection">
Bill Wendling3e1258b2009-02-08 04:04:40 +0000[diff] [blame]6364 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6365</div>
6366
6367<div class="doc_text">
6368
6369<h5>Syntax:</h5>
6370
6371<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]6372on any integer bit width.</p>
Bill Wendling3f8cebe2009-02-08 01:40:31 +0000[diff] [blame]6373
6374<pre>
6375 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6376 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6377 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6378</pre>
6379
6380<h5>Overview:</h5>
6381
6382<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6383a signed multiplication of the two arguments, and indicate whether an overflow
6384occurred during the signed multiplication.</p>
6385
6386<h5>Arguments:</h5>
6387
6388<p>The arguments (%a and %b) and the first element of the result structure may
6389be of integer types of any bit width, but they must have the same bit width. The
6390second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6391and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6392
6393<h5>Semantics:</h5>
6394
6395<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6396a signed multiplication of the two arguments. They return a structure &mdash;
6397the first element of which is the multiplication, and the second element of
6398which is a bit specifying if the signed multiplication resulted in an
6399overflow.</p>
6400
6401<h5>Examples:</h5>
6402<pre>
6403 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6404 %sum = extractvalue {i32, i1} %res, 0
6405 %obit = extractvalue {i32, i1} %res, 1
6406 br i1 %obit, label %overflow, label %normal
6407</pre>
6408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6409</div>
6410
Bill Wendlingbda98b62009-02-08 23:00:09 +0000[diff] [blame]6411<!-- _______________________________________________________________________ -->
6412<div class="doc_subsubsection">
6413 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6414</div>
6415
6416<div class="doc_text">
6417
6418<h5>Syntax:</h5>
6419
6420<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6421on any integer bit width.</p>
6422
6423<pre>
6424 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6425 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6426 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6427</pre>
6428
6429<h5>Overview:</h5>
6430
6431<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6432actively being fixed, but it should not currently be used!</i></p>
6433
6434<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6435a unsigned multiplication of the two arguments, and indicate whether an overflow
6436occurred during the unsigned multiplication.</p>
6437
6438<h5>Arguments:</h5>
6439
6440<p>The arguments (%a and %b) and the first element of the result structure may
6441be of integer types of any bit width, but they must have the same bit width. The
6442second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6443and <tt>%b</tt> are the two values that will undergo unsigned
6444multiplication.</p>
6445
6446<h5>Semantics:</h5>
6447
6448<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6449an unsigned multiplication of the two arguments. They return a structure &mdash;
6450the first element of which is the multiplication, and the second element of
6451which is a bit specifying if the unsigned multiplication resulted in an
6452overflow.</p>
6453
6454<h5>Examples:</h5>
6455<pre>
6456 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6457 %sum = extractvalue {i32, i1} %res, 0
6458 %obit = extractvalue {i32, i1} %res, 1
6459 br i1 %obit, label %overflow, label %normal
6460</pre>
6461
6462</div>
6463
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6464<!-- ======================================================================= -->
6465<div class="doc_subsection">
6466 <a name="int_debugger">Debugger Intrinsics</a>
6467</div>
6468
6469<div class="doc_text">
6470<p>
6471The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6472are described in the <a
6473href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6474Debugging</a> document.
6475</p>
6476</div>
6477
6478
6479<!-- ======================================================================= -->
6480<div class="doc_subsection">
6481 <a name="int_eh">Exception Handling Intrinsics</a>
6482</div>
6483
6484<div class="doc_text">
6485<p> The LLVM exception handling intrinsics (which all start with
6486<tt>llvm.eh.</tt> prefix), are described in the <a
6487href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6488Handling</a> document. </p>
6489</div>
6490
6491<!-- ======================================================================= -->
6492<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6493 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6494</div>
6495
6496<div class="doc_text">
6497<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6498 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6499 the <tt>nest</tt> attribute, from a function. The result is a callable
6500 function pointer lacking the nest parameter - the caller does not need
6501 to provide a value for it. Instead, the value to use is stored in
6502 advance in a "trampoline", a block of memory usually allocated
6503 on the stack, which also contains code to splice the nest value into the
6504 argument list. This is used to implement the GCC nested function address
6505 extension.
6506</p>
6507<p>
6508 For example, if the function is
6509 <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]6510 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]6511<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6512 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6513 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6514 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6515 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6516</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]6517 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6518 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6519</div>
6520
6521<!-- _______________________________________________________________________ -->
6522<div class="doc_subsubsection">
6523 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6524</div>
6525<div class="doc_text">
6526<h5>Syntax:</h5>
6527<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6528declare 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]6529</pre>
6530<h5>Overview:</h5>
6531<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6532 This fills the memory pointed to by <tt>tramp</tt> with code
6533 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6534</p>
6535<h5>Arguments:</h5>
6536<p>
6537 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6538 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6539 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]6540 intrinsic. Note that the size and the alignment are target-specific - LLVM
6541 currently provides no portable way of determining them, so a front-end that
6542 generates this intrinsic needs to have some target-specific knowledge.
6543 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]6544</p>
6545<h5>Semantics:</h5>
6546<p>
6547 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6548 dependent code, turning it into a function. A pointer to this function is
6549 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6550 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]6551 before being called. The new function's signature is the same as that of
6552 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6553 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6554 of pointer type. Calling the new function is equivalent to calling
6555 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6556 missing <tt>nest</tt> argument. If, after calling
6557 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6558 modified, then the effect of any later call to the returned function pointer is
6559 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]6560</p>
6561</div>
6562
6563<!-- ======================================================================= -->
6564<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6565 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6566</div>
6567
6568<div class="doc_text">
6569<p>
6570 These intrinsic functions expand the "universal IR" of LLVM to represent
6571 hardware constructs for atomic operations and memory synchronization. This
6572 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]6573 is aimed at a low enough level to allow any programming models or APIs
6574 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6575 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6576 hardware behavior. Just as hardware provides a "universal IR" for source
6577 languages, it also provides a starting point for developing a "universal"
6578 atomic operation and synchronization IR.
6579</p>
6580<p>
6581 These do <em>not</em> form an API such as high-level threading libraries,
6582 software transaction memory systems, atomic primitives, and intrinsic
6583 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6584 application libraries. The hardware interface provided by LLVM should allow
6585 a clean implementation of all of these APIs and parallel programming models.
6586 No one model or paradigm should be selected above others unless the hardware
6587 itself ubiquitously does so.
6588
6589</p>
6590</div>
6591
6592<!-- _______________________________________________________________________ -->
6593<div class="doc_subsubsection">
6594 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6595</div>
6596<div class="doc_text">
6597<h5>Syntax:</h5>
6598<pre>
6599declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6600i1 &lt;device&gt; )
6601
6602</pre>
6603<h5>Overview:</h5>
6604<p>
6605 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6606 specific pairs of memory access types.
6607</p>
6608<h5>Arguments:</h5>
6609<p>
6610 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6611 The first four arguments enables a specific barrier as listed below. The fith
6612 argument specifies that the barrier applies to io or device or uncached memory.
6613
6614</p>
6615 <ul>
6616 <li><tt>ll</tt>: load-load barrier</li>
6617 <li><tt>ls</tt>: load-store barrier</li>
6618 <li><tt>sl</tt>: store-load barrier</li>
6619 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6620 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6621 </ul>
6622<h5>Semantics:</h5>
6623<p>
6624 This intrinsic causes the system to enforce some ordering constraints upon
6625 the loads and stores of the program. This barrier does not indicate
6626 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6627 which they occur. For any of the specified pairs of load and store operations
6628 (f.ex. load-load, or store-load), all of the first operations preceding the
6629 barrier will complete before any of the second operations succeeding the
6630 barrier begin. Specifically the semantics for each pairing is as follows:
6631</p>
6632 <ul>
6633 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6634 after the barrier begins.</li>
6635
6636 <li><tt>ls</tt>: All loads before the barrier must complete before any
6637 store after the barrier begins.</li>
6638 <li><tt>ss</tt>: All stores before the barrier must complete before any
6639 store after the barrier begins.</li>
6640 <li><tt>sl</tt>: All stores before the barrier must complete before any
6641 load after the barrier begins.</li>
6642 </ul>
6643<p>
6644 These semantics are applied with a logical "and" behavior when more than one
6645 is enabled in a single memory barrier intrinsic.
6646</p>
6647<p>
6648 Backends may implement stronger barriers than those requested when they do not
6649 support as fine grained a barrier as requested. Some architectures do not
6650 need all types of barriers and on such architectures, these become noops.
6651</p>
6652<h5>Example:</h5>
6653<pre>
6654%ptr = malloc i32
6655 store i32 4, %ptr
6656
6657%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6658 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6659 <i>; guarantee the above finishes</i>
6660 store i32 8, %ptr <i>; before this begins</i>
6661</pre>
6662</div>
6663
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6664<!-- _______________________________________________________________________ -->
6665<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6666 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6667</div>
6668<div class="doc_text">
6669<h5>Syntax:</h5>
6670<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6671 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6672 any integer bit width and for different address spaces. Not all targets
6673 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6674
6675<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6676declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6677declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6678declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6679declare 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]6680
6681</pre>
6682<h5>Overview:</h5>
6683<p>
6684 This loads a value in memory and compares it to a given value. If they are
6685 equal, it stores a new value into the memory.
6686</p>
6687<h5>Arguments:</h5>
6688<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6689 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6690 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6691 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6692 this integer type. While any bit width integer may be used, targets may only
6693 lower representations they support in hardware.
6694
6695</p>
6696<h5>Semantics:</h5>
6697<p>
6698 This entire intrinsic must be executed atomically. It first loads the value
6699 in memory pointed to by <tt>ptr</tt> and compares it with the value
6700 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6701 loaded value is yielded in all cases. This provides the equivalent of an
6702 atomic compare-and-swap operation within the SSA framework.
6703</p>
6704<h5>Examples:</h5>
6705
6706<pre>
6707%ptr = malloc i32
6708 store i32 4, %ptr
6709
6710%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6711%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6712 <i>; yields {i32}:result1 = 4</i>
6713%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6714%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6715
6716%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6717%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6718 <i>; yields {i32}:result2 = 8</i>
6719%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6720
6721%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6722</pre>
6723</div>
6724
6725<!-- _______________________________________________________________________ -->
6726<div class="doc_subsubsection">
6727 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6728</div>
6729<div class="doc_text">
6730<h5>Syntax:</h5>
6731
6732<p>
6733 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6734 integer bit width. Not all targets support all bit widths however.</p>
6735<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6736declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6737declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6738declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6739declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6740
6741</pre>
6742<h5>Overview:</h5>
6743<p>
6744 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6745 the value from memory. It then stores the value in <tt>val</tt> in the memory
6746 at <tt>ptr</tt>.
6747</p>
6748<h5>Arguments:</h5>
6749
6750<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6751 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6752 <tt>val</tt> argument and the result must be integers of the same bit width.
6753 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6754 integer type. The targets may only lower integer representations they
6755 support.
6756</p>
6757<h5>Semantics:</h5>
6758<p>
6759 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6760 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6761 equivalent of an atomic swap operation within the SSA framework.
6762
6763</p>
6764<h5>Examples:</h5>
6765<pre>
6766%ptr = malloc i32
6767 store i32 4, %ptr
6768
6769%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6770%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6771 <i>; yields {i32}:result1 = 4</i>
6772%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6773%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6774
6775%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6776%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6777 <i>; yields {i32}:result2 = 8</i>
6778
6779%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6780%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6781</pre>
6782</div>
6783
6784<!-- _______________________________________________________________________ -->
6785<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6786 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6787
6788</div>
6789<div class="doc_text">
6790<h5>Syntax:</h5>
6791<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6792 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]6793 integer bit width. Not all targets support all bit widths however.</p>
6794<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6795declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6796declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6797declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6798declare 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]6799
6800</pre>
6801<h5>Overview:</h5>
6802<p>
6803 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6804 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6805</p>
6806<h5>Arguments:</h5>
6807<p>
6808
6809 The intrinsic takes two arguments, the first a pointer to an integer value
6810 and the second an integer value. The result is also an integer value. These
6811 integer types can have any bit width, but they must all have the same bit
6812 width. The targets may only lower integer representations they support.
6813</p>
6814<h5>Semantics:</h5>
6815<p>
6816 This intrinsic does a series of operations atomically. It first loads the
6817 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6818 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6819</p>
6820
6821<h5>Examples:</h5>
6822<pre>
6823%ptr = malloc i32
6824 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6825%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6826 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6827%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6828 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6829%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6830 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6831%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6832</pre>
6833</div>
6834
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6835<!-- _______________________________________________________________________ -->
6836<div class="doc_subsubsection">
6837 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6838
6839</div>
6840<div class="doc_text">
6841<h5>Syntax:</h5>
6842<p>
6843 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]6844 any integer bit width and for different address spaces. Not all targets
6845 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6846<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6847declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6848declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6849declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6850declare 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]6851
6852</pre>
6853<h5>Overview:</h5>
6854<p>
6855 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6856 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6857</p>
6858<h5>Arguments:</h5>
6859<p>
6860
6861 The intrinsic takes two arguments, the first a pointer to an integer value
6862 and the second an integer value. The result is also an integer value. These
6863 integer types can have any bit width, but they must all have the same bit
6864 width. The targets may only lower integer representations they support.
6865</p>
6866<h5>Semantics:</h5>
6867<p>
6868 This intrinsic does a series of operations atomically. It first loads the
6869 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6870 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6871</p>
6872
6873<h5>Examples:</h5>
6874<pre>
6875%ptr = malloc i32
6876 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6877%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6878 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6879%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6880 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6881%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6882 <i>; yields {i32}:result3 = 2</i>
6883%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6884</pre>
6885</div>
6886
6887<!-- _______________________________________________________________________ -->
6888<div class="doc_subsubsection">
6889 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6890 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6891 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6892 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6893
6894</div>
6895<div class="doc_text">
6896<h5>Syntax:</h5>
6897<p>
6898 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6899 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6900 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6901 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6902<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6903declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6904declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6905declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6906declare 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]6907
6908</pre>
6909
6910<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6911declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6912declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6913declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6914declare 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]6915
6916</pre>
6917
6918<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6919declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6920declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6921declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6922declare 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]6923
6924</pre>
6925
6926<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6927declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6928declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6929declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6930declare 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]6931
6932</pre>
6933<h5>Overview:</h5>
6934<p>
6935 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6936 the value stored in memory at <tt>ptr</tt>. It yields the original value
6937 at <tt>ptr</tt>.
6938</p>
6939<h5>Arguments:</h5>
6940<p>
6941
6942 These intrinsics take two arguments, the first a pointer to an integer value
6943 and the second an integer value. The result is also an integer value. These
6944 integer types can have any bit width, but they must all have the same bit
6945 width. The targets may only lower integer representations they support.
6946</p>
6947<h5>Semantics:</h5>
6948<p>
6949 These intrinsics does a series of operations atomically. They first load the
6950 value stored at <tt>ptr</tt>. They then do the bitwise operation
6951 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6952 value stored at <tt>ptr</tt>.
6953</p>
6954
6955<h5>Examples:</h5>
6956<pre>
6957%ptr = malloc i32
6958 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6959%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6960 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6961%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6962 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6963%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6964 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6965%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6966 <i>; yields {i32}:result3 = FF</i>
6967%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6968</pre>
6969</div>
6970
6971
6972<!-- _______________________________________________________________________ -->
6973<div class="doc_subsubsection">
6974 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6975 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6976 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6977 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6978
6979</div>
6980<div class="doc_text">
6981<h5>Syntax:</h5>
6982<p>
6983 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6984 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6985 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6986 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6987 support all bit widths however.</p>
6988<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6989declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6990declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6991declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6992declare 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]6993
6994</pre>
6995
6996<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6997declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6998declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6999declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7000declare 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]7001
7002</pre>
7003
7004<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7005declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7006declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7007declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7008declare 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]7009
7010</pre>
7011
7012<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7013declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
7014declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
7015declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
7016declare 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]7017
7018</pre>
7019<h5>Overview:</h5>
7020<p>
7021 These intrinsics takes the signed or unsigned minimum or maximum of
7022 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
7023 original value at <tt>ptr</tt>.
7024</p>
7025<h5>Arguments:</h5>
7026<p>
7027
7028 These intrinsics take two arguments, the first a pointer to an integer value
7029 and the second an integer value. The result is also an integer value. These
7030 integer types can have any bit width, but they must all have the same bit
7031 width. The targets may only lower integer representations they support.
7032</p>
7033<h5>Semantics:</h5>
7034<p>
7035 These intrinsics does a series of operations atomically. They first load the
7036 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
7037 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
7038 the original value stored at <tt>ptr</tt>.
7039</p>
7040
7041<h5>Examples:</h5>
7042<pre>
7043%ptr = malloc i32
7044 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7045%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7046 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7047%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7048 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7049%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7050 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]7051%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]7052 <i>; yields {i32}:result3 = 8</i>
7053%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
7054</pre>
7055</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]7056
7057<!-- ======================================================================= -->
7058<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7059 <a name="int_general">General Intrinsics</a>
7060</div>
7061
7062<div class="doc_text">
7063<p> This class of intrinsics is designed to be generic and has
7064no specific purpose. </p>
7065</div>
7066
7067<!-- _______________________________________________________________________ -->
7068<div class="doc_subsubsection">
7069 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
7070</div>
7071
7072<div class="doc_text">
7073
7074<h5>Syntax:</h5>
7075<pre>
7076 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7077</pre>
7078
7079<h5>Overview:</h5>
7080
7081<p>
7082The '<tt>llvm.var.annotation</tt>' intrinsic
7083</p>
7084
7085<h5>Arguments:</h5>
7086
7087<p>
7088The first argument is a pointer to a value, the second is a pointer to a
7089global string, the third is a pointer to a global string which is the source
7090file name, and the last argument is the line number.
7091</p>
7092
7093<h5>Semantics:</h5>
7094
7095<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7096This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7097This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7098annotations. These have no other defined use, they are ignored by code
7099generation and optimization.
7100</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7101</div>
7102
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7103<!-- _______________________________________________________________________ -->
7104<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]7105 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7106</div>
7107
7108<div class="doc_text">
7109
7110<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7111<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
7112any integer bit width.
7113</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7114<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]7115 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7116 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7117 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7118 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
7119 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]7120</pre>
7121
7122<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7123
7124<p>
7125The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7126</p>
7127
7128<h5>Arguments:</h5>
7129
7130<p>
7131The first argument is an integer value (result of some expression),
7132the second is a pointer to a global string, the third is a pointer to a global
7133string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]7134It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7135</p>
7136
7137<h5>Semantics:</h5>
7138
7139<p>
7140This intrinsic allows annotations to be put on arbitrary expressions
7141with arbitrary strings. This can be useful for special purpose optimizations
7142that want to look for these annotations. These have no other defined use, they
7143are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]7144</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]7145</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7146
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]7147<!-- _______________________________________________________________________ -->
7148<div class="doc_subsubsection">
7149 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7150</div>
7151
7152<div class="doc_text">
7153
7154<h5>Syntax:</h5>
7155<pre>
7156 declare void @llvm.trap()
7157</pre>
7158
7159<h5>Overview:</h5>
7160
7161<p>
7162The '<tt>llvm.trap</tt>' intrinsic
7163</p>
7164
7165<h5>Arguments:</h5>
7166
7167<p>
7168None
7169</p>
7170
7171<h5>Semantics:</h5>
7172
7173<p>
7174This intrinsics is lowered to the target dependent trap instruction. If the
7175target does not have a trap instruction, this intrinsic will be lowered to the
7176call of the abort() function.
7177</p>
7178</div>
7179
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7180<!-- _______________________________________________________________________ -->
7181<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]7182 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]7183</div>
7184<div class="doc_text">
7185<h5>Syntax:</h5>
7186<pre>
7187declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
7188
7189</pre>
7190<h5>Overview:</h5>
7191<p>
7192 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
7193 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
7194 it is placed on the stack before local variables.
7195</p>
7196<h5>Arguments:</h5>
7197<p>
7198 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
7199 first argument is the value loaded from the stack guard
7200 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
7201 has enough space to hold the value of the guard.
7202</p>
7203<h5>Semantics:</h5>
7204<p>
7205 This intrinsic causes the prologue/epilogue inserter to force the position of
7206 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7207 stack. This is to ensure that if a local variable on the stack is overwritten,
7208 it will destroy the value of the guard. When the function exits, the guard on
7209 the stack is checked against the original guard. If they're different, then
7210 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
7211</p>
7212</div>
7213
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7214<!-- *********************************************************************** -->
7215<hr>
7216<address>
7217 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7218 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7219 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]7220 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]7221
7222 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
7223 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
7224 Last modified: $Date$
7225</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]7226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]7227</body>
7228</html>