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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>
25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Functions</a></li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]29 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]30 <li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]31 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
32 <li><a href="#datalayout">Data Layout</a></li>
33 </ol>
34 </li>
35 <li><a href="#typesystem">Type System</a>
36 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]38 <li><a href="#t_primitive">Primitive Types</a>
39 <ol>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]40 <li><a href="#t_floating">Floating Point Types</a></li>
41 <li><a href="#t_void">Void Type</a></li>
42 <li><a href="#t_label">Label Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]43 </ol>
44 </li>
45 <li><a href="#t_derived">Derived Types</a>
46 <ol>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]47 <li><a href="#t_integer">Integer Type</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]48 <li><a href="#t_array">Array Type</a></li>
49 <li><a href="#t_function">Function Type</a></li>
50 <li><a href="#t_pointer">Pointer Type</a></li>
51 <li><a href="#t_struct">Structure Type</a></li>
52 <li><a href="#t_pstruct">Packed Structure Type</a></li>
53 <li><a href="#t_vector">Vector Type</a></li>
54 <li><a href="#t_opaque">Opaque Type</a></li>
55 </ol>
56 </li>
57 </ol>
58 </li>
59 <li><a href="#constants">Constants</a>
60 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]61 <li><a href="#simpleconstants">Simple Constants</a></li>
62 <li><a href="#aggregateconstants">Aggregate Constants</a></li>
63 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
64 <li><a href="#undefvalues">Undefined Values</a></li>
65 <li><a href="#constantexprs">Constant Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]66 </ol>
67 </li>
68 <li><a href="#othervalues">Other Values</a>
69 <ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]70 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]71 </ol>
72 </li>
73 <li><a href="#instref">Instruction Reference</a>
74 <ol>
75 <li><a href="#terminators">Terminator Instructions</a>
76 <ol>
77 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
78 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
79 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
80 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
81 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
82 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
83 </ol>
84 </li>
85 <li><a href="#binaryops">Binary Operations</a>
86 <ol>
87 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
88 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
89 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
90 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
91 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
92 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
93 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
94 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
95 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
96 </ol>
97 </li>
98 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
99 <ol>
100 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
101 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
102 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
103 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
104 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
105 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
106 </ol>
107 </li>
108 <li><a href="#vectorops">Vector Operations</a>
109 <ol>
110 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
111 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
112 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
113 </ol>
114 </li>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]115 <li><a href="#aggregateops">Aggregate Operations</a>
116 <ol>
117 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
118 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
119 </ol>
120 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]121 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
122 <ol>
123 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
124 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
125 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
126 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
127 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
128 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
129 </ol>
130 </li>
131 <li><a href="#convertops">Conversion Operations</a>
132 <ol>
133 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
134 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
135 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
136 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
137 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
140 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
141 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
142 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
143 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
144 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
145 </ol>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]146 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]147 <li><a href="#otherops">Other Operations</a>
148 <ol>
149 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
150 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]151 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
152 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]153 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
154 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
155 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
156 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
157 </ol>
158 </li>
159 </ol>
160 </li>
161 <li><a href="#intrinsics">Intrinsic Functions</a>
162 <ol>
163 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
164 <ol>
165 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
166 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
167 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
168 </ol>
169 </li>
170 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
171 <ol>
172 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
173 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
174 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
175 </ol>
176 </li>
177 <li><a href="#int_codegen">Code Generator Intrinsics</a>
178 <ol>
179 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
180 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
181 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
182 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
183 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
184 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
185 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
186 </ol>
187 </li>
188 <li><a href="#int_libc">Standard C Library Intrinsics</a>
189 <ol>
190 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
191 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
192 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
193 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]195 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]198 </ol>
199 </li>
200 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
201 <ol>
202 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
203 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
204 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
205 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
206 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
208 </ol>
209 </li>
210 <li><a href="#int_debugger">Debugger intrinsics</a></li>
211 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]212 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]213 <ol>
214 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]215 </ol>
216 </li>
Bill Wendling9127adb2008-11-18 22:10:53 +0000[diff] [blame]217 <li><a href="#int_atomics">Atomic intrinsics</a>
218 <ol>
219 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
220 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
221 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
222 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
223 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
224 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
225 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
226 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
227 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
228 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
229 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
230 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
231 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
232 </ol>
233 </li>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]234 <li><a href="#int_general">General intrinsics</a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]235 <ol>
Reid Spencerb043f672007-07-20 19:59:11 +0000[diff] [blame]236 <li><a href="#int_var_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]237 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]238 <li><a href="#int_annotation">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]239 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]240 <li><a href="#int_trap">
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]241 '<tt>llvm.trap</tt>' Intrinsic</a></li>
242 <li><a href="#int_stackprotector">
243 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]244 </ol>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]245 </li>
246 </ol>
247 </li>
248</ol>
249
250<div class="doc_author">
251 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
252 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
253</div>
254
255<!-- *********************************************************************** -->
256<div class="doc_section"> <a name="abstract">Abstract </a></div>
257<!-- *********************************************************************** -->
258
259<div class="doc_text">
260<p>This document is a reference manual for the LLVM assembly language.
Bill Wendlinge7846a52008-08-05 22:29:16 +0000[diff] [blame]261LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]262type safety, low-level operations, flexibility, and the capability of
263representing 'all' high-level languages cleanly. It is the common code
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]264representation used throughout all phases of the LLVM compilation
265strategy.</p>
266</div>
267
268<!-- *********************************************************************** -->
269<div class="doc_section"> <a name="introduction">Introduction</a> </div>
270<!-- *********************************************************************** -->
271
272<div class="doc_text">
273
274<p>The LLVM code representation is designed to be used in three
275different forms: as an in-memory compiler IR, as an on-disk bitcode
276representation (suitable for fast loading by a Just-In-Time compiler),
277and as a human readable assembly language representation. This allows
278LLVM to provide a powerful intermediate representation for efficient
279compiler transformations and analysis, while providing a natural means
280to debug and visualize the transformations. The three different forms
281of LLVM are all equivalent. This document describes the human readable
282representation and notation.</p>
283
284<p>The LLVM representation aims to be light-weight and low-level
285while being expressive, typed, and extensible at the same time. It
286aims to be a "universal IR" of sorts, by being at a low enough level
287that high-level ideas may be cleanly mapped to it (similar to how
288microprocessors are "universal IR's", allowing many source languages to
289be mapped to them). By providing type information, LLVM can be used as
290the target of optimizations: for example, through pointer analysis, it
291can be proven that a C automatic variable is never accessed outside of
292the current function... allowing it to be promoted to a simple SSA
293value instead of a memory location.</p>
294
295</div>
296
297<!-- _______________________________________________________________________ -->
298<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
299
300<div class="doc_text">
301
302<p>It is important to note that this document describes 'well formed'
303LLVM assembly language. There is a difference between what the parser
304accepts and what is considered 'well formed'. For example, the
305following instruction is syntactically okay, but not well formed:</p>
306
307<div class="doc_code">
308<pre>
309%x = <a href="#i_add">add</a> i32 1, %x
310</pre>
311</div>
312
313<p>...because the definition of <tt>%x</tt> does not dominate all of
314its uses. The LLVM infrastructure provides a verification pass that may
315be used to verify that an LLVM module is well formed. This pass is
316automatically run by the parser after parsing input assembly and by
317the optimizer before it outputs bitcode. The violations pointed out
318by the verifier pass indicate bugs in transformation passes or input to
319the parser.</p>
320</div>
321
Chris Lattnera83fdc02007-10-03 17:34:29 +0000[diff] [blame]322<!-- Describe the typesetting conventions here. -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]323
324<!-- *********************************************************************** -->
325<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
326<!-- *********************************************************************** -->
327
328<div class="doc_text">
329
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]330 <p>LLVM identifiers come in two basic types: global and local. Global
331 identifiers (functions, global variables) begin with the @ character. Local
332 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]333 there are three different formats for identifiers, for different purposes:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]334
335<ol>
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]336 <li>Named values are represented as a string of characters with their prefix.
337 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
338 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]339 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar73f9a772008-10-14 23:51:43 +0000[diff] [blame]340 with quotes. Special characters may be escaped using "\xx" where xx is the
341 ASCII code for the character in hexadecimal. In this way, any character can
342 be used in a name value, even quotes themselves.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]343
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]344 <li>Unnamed values are represented as an unsigned numeric value with their
345 prefix. For example, %12, @2, %44.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]346
347 <li>Constants, which are described in a <a href="#constants">section about
348 constants</a>, below.</li>
349</ol>
350
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]351<p>LLVM requires that values start with a prefix for two reasons: Compilers
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]352don't need to worry about name clashes with reserved words, and the set of
353reserved words may be expanded in the future without penalty. Additionally,
354unnamed identifiers allow a compiler to quickly come up with a temporary
355variable without having to avoid symbol table conflicts.</p>
356
357<p>Reserved words in LLVM are very similar to reserved words in other
358languages. There are keywords for different opcodes
359('<tt><a href="#i_add">add</a></tt>',
360 '<tt><a href="#i_bitcast">bitcast</a></tt>',
361 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
362href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
363and others. These reserved words cannot conflict with variable names, because
Reid Spencerc8245b02007-08-07 14:34:28 +0000[diff] [blame]364none of them start with a prefix character ('%' or '@').</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]365
366<p>Here is an example of LLVM code to multiply the integer variable
367'<tt>%X</tt>' by 8:</p>
368
369<p>The easy way:</p>
370
371<div class="doc_code">
372<pre>
373%result = <a href="#i_mul">mul</a> i32 %X, 8
374</pre>
375</div>
376
377<p>After strength reduction:</p>
378
379<div class="doc_code">
380<pre>
381%result = <a href="#i_shl">shl</a> i32 %X, i8 3
382</pre>
383</div>
384
385<p>And the hard way:</p>
386
387<div class="doc_code">
388<pre>
389<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
390<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
391%result = <a href="#i_add">add</a> i32 %1, %1
392</pre>
393</div>
394
395<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
396important lexical features of LLVM:</p>
397
398<ol>
399
400 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
401 line.</li>
402
403 <li>Unnamed temporaries are created when the result of a computation is not
404 assigned to a named value.</li>
405
406 <li>Unnamed temporaries are numbered sequentially</li>
407
408</ol>
409
410<p>...and it also shows a convention that we follow in this document. When
411demonstrating instructions, we will follow an instruction with a comment that
412defines the type and name of value produced. Comments are shown in italic
413text.</p>
414
415</div>
416
417<!-- *********************************************************************** -->
418<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
419<!-- *********************************************************************** -->
420
421<!-- ======================================================================= -->
422<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
423</div>
424
425<div class="doc_text">
426
427<p>LLVM programs are composed of "Module"s, each of which is a
428translation unit of the input programs. Each module consists of
429functions, global variables, and symbol table entries. Modules may be
430combined together with the LLVM linker, which merges function (and
431global variable) definitions, resolves forward declarations, and merges
432symbol table entries. Here is an example of the "hello world" module:</p>
433
434<div class="doc_code">
435<pre><i>; Declare the string constant as a global constant...</i>
436<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
437 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
438
439<i>; External declaration of the puts function</i>
440<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
441
442<i>; Definition of main function</i>
443define i32 @main() { <i>; i32()* </i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame^]444 <i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]445 %cast210 = <a
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame^]446 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]447
448 <i>; Call puts function to write out the string to stdout...</i>
449 <a
450 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
451 <a
452 href="#i_ret">ret</a> i32 0<br>}<br>
453</pre>
454</div>
455
456<p>This example is made up of a <a href="#globalvars">global variable</a>
457named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
458function, and a <a href="#functionstructure">function definition</a>
459for "<tt>main</tt>".</p>
460
461<p>In general, a module is made up of a list of global values,
462where both functions and global variables are global values. Global values are
463represented by a pointer to a memory location (in this case, a pointer to an
464array of char, and a pointer to a function), and have one of the following <a
465href="#linkage">linkage types</a>.</p>
466
467</div>
468
469<!-- ======================================================================= -->
470<div class="doc_subsection">
471 <a name="linkage">Linkage Types</a>
472</div>
473
474<div class="doc_text">
475
476<p>
477All Global Variables and Functions have one of the following types of linkage:
478</p>
479
480<dl>
481
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]482 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]483
484 <dd>Global values with internal linkage are only directly accessible by
485 objects in the current module. In particular, linking code into a module with
486 an internal global value may cause the internal to be renamed as necessary to
487 avoid collisions. Because the symbol is internal to the module, all
488 references can be updated. This corresponds to the notion of the
489 '<tt>static</tt>' keyword in C.
490 </dd>
491
492 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
493
494 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
495 the same name when linkage occurs. This is typically used to implement
496 inline functions, templates, or other code which must be generated in each
497 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
498 allowed to be discarded.
499 </dd>
500
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]501 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
502
503 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
504 linkage, except that unreferenced <tt>common</tt> globals may not be
505 discarded. This is used for globals that may be emitted in multiple
506 translation units, but that are not guaranteed to be emitted into every
507 translation unit that uses them. One example of this is tentative
508 definitions in C, such as "<tt>int X;</tt>" at global scope.
509 </dd>
510
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]511 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
512
Dale Johannesen96e7e092008-05-23 23:13:41 +0000[diff] [blame]513 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
514 that some targets may choose to emit different assembly sequences for them
515 for target-dependent reasons. This is used for globals that are declared
516 "weak" in C source code.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]517 </dd>
518
519 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
520
521 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
522 pointer to array type. When two global variables with appending linkage are
523 linked together, the two global arrays are appended together. This is the
524 LLVM, typesafe, equivalent of having the system linker append together
525 "sections" with identical names when .o files are linked.
526 </dd>
527
528 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]529 <dd>The semantics of this linkage follow the ELF object file model: the
530 symbol is weak until linked, if not linked, the symbol becomes null instead
531 of being an undefined reference.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]532 </dd>
533
534 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
535
536 <dd>If none of the above identifiers are used, the global is externally
537 visible, meaning that it participates in linkage and can be used to resolve
538 external symbol references.
539 </dd>
540</dl>
541
542 <p>
543 The next two types of linkage are targeted for Microsoft Windows platform
544 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]545 DLLs (Dynamic Link Libraries).
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]546 </p>
547
548 <dl>
549 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
550
551 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
552 or variable via a global pointer to a pointer that is set up by the DLL
553 exporting the symbol. On Microsoft Windows targets, the pointer name is
554 formed by combining <code>_imp__</code> and the function or variable name.
555 </dd>
556
557 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
558
559 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
560 pointer to a pointer in a DLL, so that it can be referenced with the
561 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
562 name is formed by combining <code>_imp__</code> and the function or variable
563 name.
564 </dd>
565
566</dl>
567
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]568<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]569variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
570variable and was linked with this one, one of the two would be renamed,
571preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
572external (i.e., lacking any linkage declarations), they are accessible
573outside of the current module.</p>
574<p>It is illegal for a function <i>declaration</i>
575to have any linkage type other than "externally visible", <tt>dllimport</tt>,
576or <tt>extern_weak</tt>.</p>
577<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]578linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]579</div>
580
581<!-- ======================================================================= -->
582<div class="doc_subsection">
583 <a name="callingconv">Calling Conventions</a>
584</div>
585
586<div class="doc_text">
587
588<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
589and <a href="#i_invoke">invokes</a> can all have an optional calling convention
590specified for the call. The calling convention of any pair of dynamic
591caller/callee must match, or the behavior of the program is undefined. The
592following calling conventions are supported by LLVM, and more may be added in
593the future:</p>
594
595<dl>
596 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
597
598 <dd>This calling convention (the default if no other calling convention is
599 specified) matches the target C calling conventions. This calling convention
600 supports varargs function calls and tolerates some mismatch in the declared
601 prototype and implemented declaration of the function (as does normal C).
602 </dd>
603
604 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
605
606 <dd>This calling convention attempts to make calls as fast as possible
607 (e.g. by passing things in registers). This calling convention allows the
608 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]609 without having to conform to an externally specified ABI (Application Binary
610 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]611 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
612 supported. This calling convention does not support varargs and requires the
613 prototype of all callees to exactly match the prototype of the function
614 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]615 </dd>
616
617 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
618
619 <dd>This calling convention attempts to make code in the caller as efficient
620 as possible under the assumption that the call is not commonly executed. As
621 such, these calls often preserve all registers so that the call does not break
622 any live ranges in the caller side. This calling convention does not support
623 varargs and requires the prototype of all callees to exactly match the
624 prototype of the function definition.
625 </dd>
626
627 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
628
629 <dd>Any calling convention may be specified by number, allowing
630 target-specific calling conventions to be used. Target specific calling
631 conventions start at 64.
632 </dd>
633</dl>
634
635<p>More calling conventions can be added/defined on an as-needed basis, to
636support pascal conventions or any other well-known target-independent
637convention.</p>
638
639</div>
640
641<!-- ======================================================================= -->
642<div class="doc_subsection">
643 <a name="visibility">Visibility Styles</a>
644</div>
645
646<div class="doc_text">
647
648<p>
649All Global Variables and Functions have one of the following visibility styles:
650</p>
651
652<dl>
653 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
654
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]655 <dd>On targets that use the ELF object file format, default visibility means
656 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]657 modules and, in shared libraries, means that the declared entity may be
658 overridden. On Darwin, default visibility means that the declaration is
659 visible to other modules. Default visibility corresponds to "external
660 linkage" in the language.
661 </dd>
662
663 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
664
665 <dd>Two declarations of an object with hidden visibility refer to the same
666 object if they are in the same shared object. Usually, hidden visibility
667 indicates that the symbol will not be placed into the dynamic symbol table,
668 so no other module (executable or shared library) can reference it
669 directly.
670 </dd>
671
672 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
673
674 <dd>On ELF, protected visibility indicates that the symbol will be placed in
675 the dynamic symbol table, but that references within the defining module will
676 bind to the local symbol. That is, the symbol cannot be overridden by another
677 module.
678 </dd>
679</dl>
680
681</div>
682
683<!-- ======================================================================= -->
684<div class="doc_subsection">
685 <a name="globalvars">Global Variables</a>
686</div>
687
688<div class="doc_text">
689
690<p>Global variables define regions of memory allocated at compilation time
691instead of run-time. Global variables may optionally be initialized, may have
692an explicit section to be placed in, and may have an optional explicit alignment
693specified. A variable may be defined as "thread_local", which means that it
694will not be shared by threads (each thread will have a separated copy of the
695variable). A variable may be defined as a global "constant," which indicates
696that the contents of the variable will <b>never</b> be modified (enabling better
697optimization, allowing the global data to be placed in the read-only section of
698an executable, etc). Note that variables that need runtime initialization
699cannot be marked "constant" as there is a store to the variable.</p>
700
701<p>
702LLVM explicitly allows <em>declarations</em> of global variables to be marked
703constant, even if the final definition of the global is not. This capability
704can be used to enable slightly better optimization of the program, but requires
705the language definition to guarantee that optimizations based on the
706'constantness' are valid for the translation units that do not include the
707definition.
708</p>
709
710<p>As SSA values, global variables define pointer values that are in
711scope (i.e. they dominate) all basic blocks in the program. Global
712variables always define a pointer to their "content" type because they
713describe a region of memory, and all memory objects in LLVM are
714accessed through pointers.</p>
715
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]716<p>A global variable may be declared to reside in a target-specifc numbered
717address space. For targets that support them, address spaces may affect how
718optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]719the variable. The default address space is zero. The address space qualifier
720must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]722<p>LLVM allows an explicit section to be specified for globals. If the target
723supports it, it will emit globals to the section specified.</p>
724
725<p>An explicit alignment may be specified for a global. If not present, or if
726the alignment is set to zero, the alignment of the global is set by the target
727to whatever it feels convenient. If an explicit alignment is specified, the
728global is forced to have at least that much alignment. All alignments must be
729a power of 2.</p>
730
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]731<p>For example, the following defines a global in a numbered address space with
732an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733
734<div class="doc_code">
735<pre>
Chris Lattner3d7cbe22009-01-02 07:02:56 +0000[diff] [blame]736@G = addrspace(5) constant float 1.0 section "foo", align 4
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]737</pre>
738</div>
739
740</div>
741
742
743<!-- ======================================================================= -->
744<div class="doc_subsection">
745 <a name="functionstructure">Functions</a>
746</div>
747
748<div class="doc_text">
749
750<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
751an optional <a href="#linkage">linkage type</a>, an optional
752<a href="#visibility">visibility style</a>, an optional
753<a href="#callingconv">calling convention</a>, a return type, an optional
754<a href="#paramattrs">parameter attribute</a> for the return type, a function
755name, a (possibly empty) argument list (each with optional
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]756<a href="#paramattrs">parameter attributes</a>), optional
757<a href="#fnattrs">function attributes</a>, an optional section,
758an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattneree202542008-10-04 18:10:21 +0000[diff] [blame]759an opening curly brace, a list of basic blocks, and a closing curly brace.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]760
761LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
762optional <a href="#linkage">linkage type</a>, an optional
763<a href="#visibility">visibility style</a>, an optional
764<a href="#callingconv">calling convention</a>, a return type, an optional
765<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]766name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksend606f5b2007-12-10 03:30:21 +0000[diff] [blame]767<a href="#gc">garbage collector name</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]768
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]769<p>A function definition contains a list of basic blocks, forming the CFG
770(Control Flow Graph) for
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]771the function. Each basic block may optionally start with a label (giving the
772basic block a symbol table entry), contains a list of instructions, and ends
773with a <a href="#terminators">terminator</a> instruction (such as a branch or
774function return).</p>
775
776<p>The first basic block in a function is special in two ways: it is immediately
777executed on entrance to the function, and it is not allowed to have predecessor
778basic blocks (i.e. there can not be any branches to the entry block of a
779function). Because the block can have no predecessors, it also cannot have any
780<a href="#i_phi">PHI nodes</a>.</p>
781
782<p>LLVM allows an explicit section to be specified for functions. If the target
783supports it, it will emit functions to the section specified.</p>
784
785<p>An explicit alignment may be specified for a function. If not present, or if
786the alignment is set to zero, the alignment of the function is set by the target
787to whatever it feels convenient. If an explicit alignment is specified, the
788function is forced to have at least that much alignment. All alignments must be
789a power of 2.</p>
790
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]791 <h5>Syntax:</h5>
792
793<div class="doc_code">
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]794<tt>
795define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
796 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
797 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
798 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
799 [<a href="#gc">gc</a>] { ... }
800</tt>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]801</div>
802
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]803</div>
804
805
806<!-- ======================================================================= -->
807<div class="doc_subsection">
808 <a name="aliasstructure">Aliases</a>
809</div>
810<div class="doc_text">
811 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov96822812008-03-22 08:36:14 +0000[diff] [blame]812 function, global variable, another alias or bitcast of global value). Aliases
813 may have an optional <a href="#linkage">linkage type</a>, and an
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]814 optional <a href="#visibility">visibility style</a>.</p>
815
816 <h5>Syntax:</h5>
817
818<div class="doc_code">
819<pre>
Duncan Sandsd7bfabf2008-09-12 20:48:21 +0000[diff] [blame]820@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]821</pre>
822</div>
823
824</div>
825
826
827
828<!-- ======================================================================= -->
829<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
830<div class="doc_text">
831 <p>The return type and each parameter of a function type may have a set of
832 <i>parameter attributes</i> associated with them. Parameter attributes are
833 used to communicate additional information about the result or parameters of
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]834 a function. Parameter attributes are considered to be part of the function,
835 not of the function type, so functions with different parameter attributes
836 can have the same function type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]837
838 <p>Parameter attributes are simple keywords that follow the type specified. If
839 multiple parameter attributes are needed, they are space separated. For
840 example:</p>
841
842<div class="doc_code">
843<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]844declare i32 @printf(i8* noalias , ...)
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]845declare i32 @atoi(i8 zeroext)
846declare signext i8 @returns_signed_char()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]847</pre>
848</div>
849
Duncan Sandsf5588dc2007-11-27 13:23:08 +0000[diff] [blame]850 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
851 <tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]852
853 <p>Currently, only the following parameter attributes are defined:</p>
854 <dl>
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]855 <dt><tt>zeroext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]856 <dd>This indicates to the code generator that the parameter or return value
857 should be zero-extended to a 32-bit value by the caller (for a parameter)
858 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]859
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]860 <dt><tt>signext</tt></dt>
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]861 <dd>This indicates to the code generator that the parameter or return value
862 should be sign-extended to a 32-bit value by the caller (for a parameter)
863 or the callee (for a return value).</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]864
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]865 <dt><tt>inreg</tt></dt>
Dale Johannesenc08a0e22008-09-25 20:47:45 +0000[diff] [blame]866 <dd>This indicates that this parameter or return value should be treated
867 in a special target-dependent fashion during while emitting code for a
868 function call or return (usually, by putting it in a register as opposed
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]869 to memory, though some targets use it to distinguish between two different
870 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]871
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]872 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]873 <dd>This indicates that the pointer parameter should really be passed by
874 value to the function. The attribute implies that a hidden copy of the
875 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]876 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner04c86182008-01-15 04:34:22 +0000[diff] [blame]877 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]878 value, but is also valid on pointers to scalars. The copy is considered to
879 belong to the caller not the callee (for example,
880 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]881 <tt>byval</tt> parameters). This is not a valid attribute for return
882 values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]884 <dt><tt>sret</tt></dt>
Duncan Sands616cc032008-02-18 04:19:38 +0000[diff] [blame]885 <dd>This indicates that the pointer parameter specifies the address of a
886 structure that is the return value of the function in the source program.
Chris Lattnerf33b8452008-10-04 18:33:34 +0000[diff] [blame]887 This pointer must be guaranteed by the caller to be valid: loads and stores
888 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]889 be applied to the first parameter. This is not a valid attribute for
890 return values. </dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]891
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]892 <dt><tt>noalias</tt></dt>
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]893 <dd>This indicates that the pointer does not alias any global or any other
894 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckya604a942008-11-24 05:00:44 +0000[diff] [blame]895 case. On a function return value, <tt>noalias</tt> additionally indicates
896 that the pointer does not alias any other pointers visible to the
Nick Lewycky40fb6f22008-12-19 06:39:12 +0000[diff] [blame]897 caller. For further details, please see the discussion of the NoAlias
898 response in
899 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
900 analysis</a>.</dd>
901
902 <dt><tt>nocapture</tt></dt>
903 <dd>This indicates that the callee does not make any copies of the pointer
904 that outlive the callee itself. This is not a valid attribute for return
905 values.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]906
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]907 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]908 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]909 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
910 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]911 </dl>
912
913</div>
914
915<!-- ======================================================================= -->
916<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]917 <a name="gc">Garbage Collector Names</a>
918</div>
919
920<div class="doc_text">
921<p>Each function may specify a garbage collector name, which is simply a
922string.</p>
923
924<div class="doc_code"><pre
925>define void @f() gc "name" { ...</pre></div>
926
927<p>The compiler declares the supported values of <i>name</i>. Specifying a
928collector which will cause the compiler to alter its output in order to support
929the named garbage collection algorithm.</p>
930</div>
931
932<!-- ======================================================================= -->
933<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]934 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]935</div>
936
937<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]938
939<p>Function attributes are set to communicate additional information about
940 a function. Function attributes are considered to be part of the function,
941 not of the function type, so functions with different parameter attributes
942 can have the same function type.</p>
943
944 <p>Function attributes are simple keywords that follow the type specified. If
945 multiple attributes are needed, they are space separated. For
946 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]947
948<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]949<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]950define void @f() noinline { ... }
951define void @f() alwaysinline { ... }
952define void @f() alwaysinline optsize { ... }
953define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]954</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]955</div>
956
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]957<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]958<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]959<dd>This attribute indicates that the inliner should attempt to inline this
960function into callers whenever possible, ignoring any active inlining size
961threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]962
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]963<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]964<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]965in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]966<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]967
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]968<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]969<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]970make choices that keep the code size of this function low, and otherwise do
971optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]972
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]973<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]974<dd>This function attribute indicates that the function never returns normally.
975This produces undefined behavior at runtime if the function ever does
976dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]977
978<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]979<dd>This function attribute indicates that the function never returns with an
980unwind or exceptional control flow. If the function does unwind, its runtime
981behavior is undefined.</dd>
982
983<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]984<dd>This attribute indicates that the function computes its result (or the
985exception it throws) based strictly on its arguments, without dereferencing any
986pointer arguments or otherwise accessing any mutable state (e.g. memory, control
987registers, etc) visible to caller functions. It does not write through any
988pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
989never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]990
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]991<dt><tt><a name="readonly">readonly</a></tt></dt>
992<dd>This attribute indicates that the function does not write through any
993pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
994or otherwise modify any state (e.g. memory, control registers, etc) visible to
995caller functions. It may dereference pointer arguments and read state that may
996be set in the caller. A readonly function always returns the same value (or
997throws the same exception) when called with the same set of arguments and global
998state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]999
1000<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1001<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1002protector. It is in the form of a "canary"&mdash;a random value placed on the
1003stack before the local variables that's checked upon return from the function to
1004see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1005needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1006
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1007<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1008that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1009have an <tt>ssp</tt> attribute.</p></dd>
1010
1011<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1012<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1013stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1014function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1015
1016<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1017function that doesn't have an <tt>sspreq</tt> attribute or which has
1018an <tt>ssp</tt> attribute, then the resulting function will have
1019an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1020</dl>
1021
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1022</div>
1023
1024<!-- ======================================================================= -->
1025<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1026 <a name="moduleasm">Module-Level Inline Assembly</a>
1027</div>
1028
1029<div class="doc_text">
1030<p>
1031Modules may contain "module-level inline asm" blocks, which corresponds to the
1032GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1033LLVM and treated as a single unit, but may be separated in the .ll file if
1034desired. The syntax is very simple:
1035</p>
1036
1037<div class="doc_code">
1038<pre>
1039module asm "inline asm code goes here"
1040module asm "more can go here"
1041</pre>
1042</div>
1043
1044<p>The strings can contain any character by escaping non-printable characters.
1045 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1046 for the number.
1047</p>
1048
1049<p>
1050 The inline asm code is simply printed to the machine code .s file when
1051 assembly code is generated.
1052</p>
1053</div>
1054
1055<!-- ======================================================================= -->
1056<div class="doc_subsection">
1057 <a name="datalayout">Data Layout</a>
1058</div>
1059
1060<div class="doc_text">
1061<p>A module may specify a target specific data layout string that specifies how
1062data is to be laid out in memory. The syntax for the data layout is simply:</p>
1063<pre> target datalayout = "<i>layout specification</i>"</pre>
1064<p>The <i>layout specification</i> consists of a list of specifications
1065separated by the minus sign character ('-'). Each specification starts with a
1066letter and may include other information after the letter to define some
1067aspect of the data layout. The specifications accepted are as follows: </p>
1068<dl>
1069 <dt><tt>E</tt></dt>
1070 <dd>Specifies that the target lays out data in big-endian form. That is, the
1071 bits with the most significance have the lowest address location.</dd>
1072 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1073 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1074 the bits with the least significance have the lowest address location.</dd>
1075 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1076 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1077 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1078 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1079 too.</dd>
1080 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1081 <dd>This specifies the alignment for an integer type of a given bit
1082 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1083 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1084 <dd>This specifies the alignment for a vector type of a given bit
1085 <i>size</i>.</dd>
1086 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1087 <dd>This specifies the alignment for a floating point type of a given bit
1088 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1089 (double).</dd>
1090 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1091 <dd>This specifies the alignment for an aggregate type of a given bit
1092 <i>size</i>.</dd>
1093</dl>
1094<p>When constructing the data layout for a given target, LLVM starts with a
1095default set of specifications which are then (possibly) overriden by the
1096specifications in the <tt>datalayout</tt> keyword. The default specifications
1097are given in this list:</p>
1098<ul>
1099 <li><tt>E</tt> - big endian</li>
1100 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1101 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1102 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1103 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1104 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1105 <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]1106 alignment of 64-bits</li>
1107 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1108 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1109 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1110 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1111 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1112</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1113<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1114following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1115<ol>
1116 <li>If the type sought is an exact match for one of the specifications, that
1117 specification is used.</li>
1118 <li>If no match is found, and the type sought is an integer type, then the
1119 smallest integer type that is larger than the bitwidth of the sought type is
1120 used. If none of the specifications are larger than the bitwidth then the the
1121 largest integer type is used. For example, given the default specifications
1122 above, the i7 type will use the alignment of i8 (next largest) while both
1123 i65 and i256 will use the alignment of i64 (largest specified).</li>
1124 <li>If no match is found, and the type sought is a vector type, then the
1125 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1126 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1127 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1128</ol>
1129</div>
1130
1131<!-- *********************************************************************** -->
1132<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1133<!-- *********************************************************************** -->
1134
1135<div class="doc_text">
1136
1137<p>The LLVM type system is one of the most important features of the
1138intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1139optimizations to be performed on the intermediate representation directly,
1140without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1141extra analyses on the side before the transformation. A strong type
1142system makes it easier to read the generated code and enables novel
1143analyses and transformations that are not feasible to perform on normal
1144three address code representations.</p>
1145
1146</div>
1147
1148<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1149<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1150Classifications</a> </div>
1151<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1152<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1153classifications:</p>
1154
1155<table border="1" cellspacing="0" cellpadding="4">
1156 <tbody>
1157 <tr><th>Classification</th><th>Types</th></tr>
1158 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1159 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1160 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1161 </tr>
1162 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1163 <td><a href="#t_floating">floating point</a></td>
1164 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1165 </tr>
1166 <tr>
1167 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1168 <td><a href="#t_integer">integer</a>,
1169 <a href="#t_floating">floating point</a>,
1170 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1171 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1172 <a href="#t_struct">structure</a>,
1173 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1174 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1175 </td>
1176 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1177 <tr>
1178 <td><a href="#t_primitive">primitive</a></td>
1179 <td><a href="#t_label">label</a>,
1180 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1181 <a href="#t_floating">floating point</a>.</td>
1182 </tr>
1183 <tr>
1184 <td><a href="#t_derived">derived</a></td>
1185 <td><a href="#t_integer">integer</a>,
1186 <a href="#t_array">array</a>,
1187 <a href="#t_function">function</a>,
1188 <a href="#t_pointer">pointer</a>,
1189 <a href="#t_struct">structure</a>,
1190 <a href="#t_pstruct">packed structure</a>,
1191 <a href="#t_vector">vector</a>,
1192 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1193 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1194 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1195 </tbody>
1196</table>
1197
1198<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1199most important. Values of these types are the only ones which can be
1200produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1201instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1202</div>
1203
1204<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1205<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1206
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1207<div class="doc_text">
1208<p>The primitive types are the fundamental building blocks of the LLVM
1209system.</p>
1210
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1211</div>
1212
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1213<!-- _______________________________________________________________________ -->
1214<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1215
1216<div class="doc_text">
1217 <table>
1218 <tbody>
1219 <tr><th>Type</th><th>Description</th></tr>
1220 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1221 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1222 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1223 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1224 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1225 </tbody>
1226 </table>
1227</div>
1228
1229<!-- _______________________________________________________________________ -->
1230<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1231
1232<div class="doc_text">
1233<h5>Overview:</h5>
1234<p>The void type does not represent any value and has no size.</p>
1235
1236<h5>Syntax:</h5>
1237
1238<pre>
1239 void
1240</pre>
1241</div>
1242
1243<!-- _______________________________________________________________________ -->
1244<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1245
1246<div class="doc_text">
1247<h5>Overview:</h5>
1248<p>The label type represents code labels.</p>
1249
1250<h5>Syntax:</h5>
1251
1252<pre>
1253 label
1254</pre>
1255</div>
1256
1257
1258<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1259<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1260
1261<div class="doc_text">
1262
1263<p>The real power in LLVM comes from the derived types in the system.
1264This is what allows a programmer to represent arrays, functions,
1265pointers, and other useful types. Note that these derived types may be
1266recursive: For example, it is possible to have a two dimensional array.</p>
1267
1268</div>
1269
1270<!-- _______________________________________________________________________ -->
1271<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1272
1273<div class="doc_text">
1274
1275<h5>Overview:</h5>
1276<p>The integer type is a very simple derived type that simply specifies an
1277arbitrary bit width for the integer type desired. Any bit width from 1 bit to
12782^23-1 (about 8 million) can be specified.</p>
1279
1280<h5>Syntax:</h5>
1281
1282<pre>
1283 iN
1284</pre>
1285
1286<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1287value.</p>
1288
1289<h5>Examples:</h5>
1290<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1291 <tbody>
1292 <tr>
1293 <td><tt>i1</tt></td>
1294 <td>a single-bit integer.</td>
1295 </tr><tr>
1296 <td><tt>i32</tt></td>
1297 <td>a 32-bit integer.</td>
1298 </tr><tr>
1299 <td><tt>i1942652</tt></td>
1300 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1301 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1302 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1303</table>
1304</div>
1305
1306<!-- _______________________________________________________________________ -->
1307<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1308
1309<div class="doc_text">
1310
1311<h5>Overview:</h5>
1312
1313<p>The array type is a very simple derived type that arranges elements
1314sequentially in memory. The array type requires a size (number of
1315elements) and an underlying data type.</p>
1316
1317<h5>Syntax:</h5>
1318
1319<pre>
1320 [&lt;# elements&gt; x &lt;elementtype&gt;]
1321</pre>
1322
1323<p>The number of elements is a constant integer value; elementtype may
1324be any type with a size.</p>
1325
1326<h5>Examples:</h5>
1327<table class="layout">
1328 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1329 <td class="left"><tt>[40 x i32]</tt></td>
1330 <td class="left">Array of 40 32-bit integer values.</td>
1331 </tr>
1332 <tr class="layout">
1333 <td class="left"><tt>[41 x i32]</tt></td>
1334 <td class="left">Array of 41 32-bit integer values.</td>
1335 </tr>
1336 <tr class="layout">
1337 <td class="left"><tt>[4 x i8]</tt></td>
1338 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1339 </tr>
1340</table>
1341<p>Here are some examples of multidimensional arrays:</p>
1342<table class="layout">
1343 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1344 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1345 <td class="left">3x4 array of 32-bit integer values.</td>
1346 </tr>
1347 <tr class="layout">
1348 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1349 <td class="left">12x10 array of single precision floating point values.</td>
1350 </tr>
1351 <tr class="layout">
1352 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1353 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1354 </tr>
1355</table>
1356
1357<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1358length array. Normally, accesses past the end of an array are undefined in
1359LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1360As a special case, however, zero length arrays are recognized to be variable
1361length. This allows implementation of 'pascal style arrays' with the LLVM
1362type "{ i32, [0 x float]}", for example.</p>
1363
1364</div>
1365
1366<!-- _______________________________________________________________________ -->
1367<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1368<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1369
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1370<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1372<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1373consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1374return 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]1375If 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]1376class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1379
1380<pre>
1381 &lt;returntype list&gt; (&lt;parameter list&gt;)
1382</pre>
1383
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1384<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1385specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1386which indicates that the function takes a variable number of arguments.
1387Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1388 href="#int_varargs">variable argument handling intrinsic</a> functions.
1389'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1390<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1392<h5>Examples:</h5>
1393<table class="layout">
1394 <tr class="layout">
1395 <td class="left"><tt>i32 (i32)</tt></td>
1396 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1397 </td>
1398 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1399 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1400 </tt></td>
1401 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1402 an <tt>i16</tt> that should be sign extended and a
1403 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1404 <tt>float</tt>.
1405 </td>
1406 </tr><tr class="layout">
1407 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1408 <td class="left">A vararg function that takes at least one
1409 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1410 which returns an integer. This is the signature for <tt>printf</tt> in
1411 LLVM.
1412 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1413 </tr><tr class="layout">
1414 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1415 <td class="left">A function taking an <tt>i32</tt>, returning two
1416 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1417 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1418 </tr>
1419</table>
1420
1421</div>
1422<!-- _______________________________________________________________________ -->
1423<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1424<div class="doc_text">
1425<h5>Overview:</h5>
1426<p>The structure type is used to represent a collection of data members
1427together in memory. The packing of the field types is defined to match
1428the ABI of the underlying processor. The elements of a structure may
1429be any type that has a size.</p>
1430<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1431and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1432field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1433instruction.</p>
1434<h5>Syntax:</h5>
1435<pre> { &lt;type list&gt; }<br></pre>
1436<h5>Examples:</h5>
1437<table class="layout">
1438 <tr class="layout">
1439 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1440 <td class="left">A triple of three <tt>i32</tt> values</td>
1441 </tr><tr class="layout">
1442 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1443 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1444 second element is a <a href="#t_pointer">pointer</a> to a
1445 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1446 an <tt>i32</tt>.</td>
1447 </tr>
1448</table>
1449</div>
1450
1451<!-- _______________________________________________________________________ -->
1452<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1453</div>
1454<div class="doc_text">
1455<h5>Overview:</h5>
1456<p>The packed structure type is used to represent a collection of data members
1457together in memory. There is no padding between fields. Further, the alignment
1458of a packed structure is 1 byte. The elements of a packed structure may
1459be any type that has a size.</p>
1460<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1461and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1462field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1463instruction.</p>
1464<h5>Syntax:</h5>
1465<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1466<h5>Examples:</h5>
1467<table class="layout">
1468 <tr class="layout">
1469 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1470 <td class="left">A triple of three <tt>i32</tt> values</td>
1471 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1472 <td class="left">
1473<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1474 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1475 second element is a <a href="#t_pointer">pointer</a> to a
1476 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1477 an <tt>i32</tt>.</td>
1478 </tr>
1479</table>
1480</div>
1481
1482<!-- _______________________________________________________________________ -->
1483<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1484<div class="doc_text">
1485<h5>Overview:</h5>
1486<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1487reference to another object, which must live in memory. Pointer types may have
1488an optional address space attribute defining the target-specific numbered
1489address space where the pointed-to object resides. The default address space is
1490zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1491<h5>Syntax:</h5>
1492<pre> &lt;type&gt; *<br></pre>
1493<h5>Examples:</h5>
1494<table class="layout">
1495 <tr class="layout">
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame^]1496 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1497 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1498 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1499 </tr>
1500 <tr class="layout">
1501 <td class="left"><tt>i32 (i32 *) *</tt></td>
1502 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1503 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1504 <tt>i32</tt>.</td>
1505 </tr>
1506 <tr class="layout">
1507 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1508 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1509 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1510 </tr>
1511</table>
1512</div>
1513
1514<!-- _______________________________________________________________________ -->
1515<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1516<div class="doc_text">
1517
1518<h5>Overview:</h5>
1519
1520<p>A vector type is a simple derived type that represents a vector
1521of elements. Vector types are used when multiple primitive data
1522are operated in parallel using a single instruction (SIMD).
1523A vector type requires a size (number of
1524elements) and an underlying primitive data type. Vectors must have a power
1525of two length (1, 2, 4, 8, 16 ...). Vector types are
1526considered <a href="#t_firstclass">first class</a>.</p>
1527
1528<h5>Syntax:</h5>
1529
1530<pre>
1531 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1532</pre>
1533
1534<p>The number of elements is a constant integer value; elementtype may
1535be any integer or floating point type.</p>
1536
1537<h5>Examples:</h5>
1538
1539<table class="layout">
1540 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1541 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1542 <td class="left">Vector of 4 32-bit integer values.</td>
1543 </tr>
1544 <tr class="layout">
1545 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1546 <td class="left">Vector of 8 32-bit floating-point values.</td>
1547 </tr>
1548 <tr class="layout">
1549 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1550 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1551 </tr>
1552</table>
1553</div>
1554
1555<!-- _______________________________________________________________________ -->
1556<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1557<div class="doc_text">
1558
1559<h5>Overview:</h5>
1560
1561<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1562corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1563In LLVM, opaque types can eventually be resolved to any type (not just a
1564structure type).</p>
1565
1566<h5>Syntax:</h5>
1567
1568<pre>
1569 opaque
1570</pre>
1571
1572<h5>Examples:</h5>
1573
1574<table class="layout">
1575 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1576 <td class="left"><tt>opaque</tt></td>
1577 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1578 </tr>
1579</table>
1580</div>
1581
1582
1583<!-- *********************************************************************** -->
1584<div class="doc_section"> <a name="constants">Constants</a> </div>
1585<!-- *********************************************************************** -->
1586
1587<div class="doc_text">
1588
1589<p>LLVM has several different basic types of constants. This section describes
1590them all and their syntax.</p>
1591
1592</div>
1593
1594<!-- ======================================================================= -->
1595<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1596
1597<div class="doc_text">
1598
1599<dl>
1600 <dt><b>Boolean constants</b></dt>
1601
1602 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1603 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1604 </dd>
1605
1606 <dt><b>Integer constants</b></dt>
1607
1608 <dd>Standard integers (such as '4') are constants of the <a
1609 href="#t_integer">integer</a> type. Negative numbers may be used with
1610 integer types.
1611 </dd>
1612
1613 <dt><b>Floating point constants</b></dt>
1614
1615 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1616 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1617 notation (see below). The assembler requires the exact decimal value of
1618 a floating-point constant. For example, the assembler accepts 1.25 but
1619 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1620 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1621
1622 <dt><b>Null pointer constants</b></dt>
1623
1624 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1625 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1626
1627</dl>
1628
1629<p>The one non-intuitive notation for constants is the optional hexadecimal form
1630of floating point constants. For example, the form '<tt>double
16310x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
16324.5e+15</tt>'. The only time hexadecimal floating point constants are required
1633(and the only time that they are generated by the disassembler) is when a
1634floating point constant must be emitted but it cannot be represented as a
1635decimal floating point number. For example, NaN's, infinities, and other
1636special values are represented in their IEEE hexadecimal format so that
1637assembly and disassembly do not cause any bits to change in the constants.</p>
1638
1639</div>
1640
1641<!-- ======================================================================= -->
1642<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1643</div>
1644
1645<div class="doc_text">
1646<p>Aggregate constants arise from aggregation of simple constants
1647and smaller aggregate constants.</p>
1648
1649<dl>
1650 <dt><b>Structure constants</b></dt>
1651
1652 <dd>Structure constants are represented with notation similar to structure
1653 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1654 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1655 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]1656 must have <a href="#t_struct">structure type</a>, and the number and
1657 types of elements must match those specified by the type.
1658 </dd>
1659
1660 <dt><b>Array constants</b></dt>
1661
1662 <dd>Array constants are represented with notation similar to array type
1663 definitions (a comma separated list of elements, surrounded by square brackets
1664 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1665 constants must have <a href="#t_array">array type</a>, and the number and
1666 types of elements must match those specified by the type.
1667 </dd>
1668
1669 <dt><b>Vector constants</b></dt>
1670
1671 <dd>Vector constants are represented with notation similar to vector type
1672 definitions (a comma separated list of elements, surrounded by
1673 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1674 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1675 href="#t_vector">vector type</a>, and the number and types of elements must
1676 match those specified by the type.
1677 </dd>
1678
1679 <dt><b>Zero initialization</b></dt>
1680
1681 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1682 value to zero of <em>any</em> type, including scalar and aggregate types.
1683 This is often used to avoid having to print large zero initializers (e.g. for
1684 large arrays) and is always exactly equivalent to using explicit zero
1685 initializers.
1686 </dd>
1687</dl>
1688
1689</div>
1690
1691<!-- ======================================================================= -->
1692<div class="doc_subsection">
1693 <a name="globalconstants">Global Variable and Function Addresses</a>
1694</div>
1695
1696<div class="doc_text">
1697
1698<p>The addresses of <a href="#globalvars">global variables</a> and <a
1699href="#functionstructure">functions</a> are always implicitly valid (link-time)
1700constants. These constants are explicitly referenced when the <a
1701href="#identifiers">identifier for the global</a> is used and always have <a
1702href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1703file:</p>
1704
1705<div class="doc_code">
1706<pre>
1707@X = global i32 17
1708@Y = global i32 42
1709@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1710</pre>
1711</div>
1712
1713</div>
1714
1715<!-- ======================================================================= -->
1716<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1717<div class="doc_text">
1718 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1719 no specific value. Undefined values may be of any type and be used anywhere
1720 a constant is permitted.</p>
1721
1722 <p>Undefined values indicate to the compiler that the program is well defined
1723 no matter what value is used, giving the compiler more freedom to optimize.
1724 </p>
1725</div>
1726
1727<!-- ======================================================================= -->
1728<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1729</div>
1730
1731<div class="doc_text">
1732
1733<p>Constant expressions are used to allow expressions involving other constants
1734to be used as constants. Constant expressions may be of any <a
1735href="#t_firstclass">first class</a> type and may involve any LLVM operation
1736that does not have side effects (e.g. load and call are not supported). The
1737following is the syntax for constant expressions:</p>
1738
1739<dl>
1740 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1741 <dd>Truncate a constant to another type. The bit size of CST must be larger
1742 than the bit size of TYPE. Both types must be integers.</dd>
1743
1744 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1745 <dd>Zero extend a constant to another type. The bit size of CST must be
1746 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1747
1748 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1749 <dd>Sign extend a constant to another type. The bit size of CST must be
1750 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1751
1752 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1753 <dd>Truncate a floating point constant to another floating point type. The
1754 size of CST must be larger than the size of TYPE. Both types must be
1755 floating point.</dd>
1756
1757 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1758 <dd>Floating point extend a constant to another type. The size of CST must be
1759 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1760
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1761 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1762 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1763 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1764 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1765 of the same number of elements. If the value won't fit in the integer type,
1766 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1767
1768 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1769 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1770 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1771 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1772 of the same number of elements. If the value won't fit in the integer type,
1773 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1774
1775 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1776 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1777 constant. TYPE must be a scalar or vector floating point type. CST must be of
1778 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1779 of the same number of elements. If the value won't fit in the floating point
1780 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1781
1782 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1783 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1784 constant. TYPE must be a scalar or vector floating point type. CST must be of
1785 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1786 of the same number of elements. If the value won't fit in the floating point
1787 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1788
1789 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1790 <dd>Convert a pointer typed constant to the corresponding integer constant
1791 TYPE must be an integer type. CST must be of pointer type. The CST value is
1792 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1793
1794 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1795 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1796 pointer type. CST must be of integer type. The CST value is zero extended,
1797 truncated, or unchanged to make it fit in a pointer size. This one is
1798 <i>really</i> dangerous!</dd>
1799
1800 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1801 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1802 identical (same number of bits). The conversion is done as if the CST value
1803 was stored to memory and read back as TYPE. In other words, no bits change
1804 with this operator, just the type. This can be used for conversion of
1805 vector types to any other type, as long as they have the same bit width. For
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]1806 pointers it is only valid to cast to another pointer type. It is not valid
1807 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1808 </dd>
1809
1810 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1811
1812 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1813 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1814 instruction, the index list may have zero or more indexes, which are required
1815 to make sense for the type of "CSTPTR".</dd>
1816
1817 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1818
1819 <dd>Perform the <a href="#i_select">select operation</a> on
1820 constants.</dd>
1821
1822 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1823 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1824
1825 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1826 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1827
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1828 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1829 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1830
1831 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1832 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1833
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1834 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1835
1836 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1837 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1838
1839 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1840
1841 <dd>Perform the <a href="#i_insertelement">insertelement
1842 operation</a> on constants.</dd>
1843
1844
1845 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1846
1847 <dd>Perform the <a href="#i_shufflevector">shufflevector
1848 operation</a> on constants.</dd>
1849
1850 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1851
1852 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1853 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1854 binary</a> operations. The constraints on operands are the same as those for
1855 the corresponding instruction (e.g. no bitwise operations on floating point
1856 values are allowed).</dd>
1857</dl>
1858</div>
1859
1860<!-- *********************************************************************** -->
1861<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1862<!-- *********************************************************************** -->
1863
1864<!-- ======================================================================= -->
1865<div class="doc_subsection">
1866<a name="inlineasm">Inline Assembler Expressions</a>
1867</div>
1868
1869<div class="doc_text">
1870
1871<p>
1872LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1873Module-Level Inline Assembly</a>) through the use of a special value. This
1874value represents the inline assembler as a string (containing the instructions
1875to emit), a list of operand constraints (stored as a string), and a flag that
1876indicates whether or not the inline asm expression has side effects. An example
1877inline assembler expression is:
1878</p>
1879
1880<div class="doc_code">
1881<pre>
1882i32 (i32) asm "bswap $0", "=r,r"
1883</pre>
1884</div>
1885
1886<p>
1887Inline assembler expressions may <b>only</b> be used as the callee operand of
1888a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1889</p>
1890
1891<div class="doc_code">
1892<pre>
1893%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1894</pre>
1895</div>
1896
1897<p>
1898Inline asms with side effects not visible in the constraint list must be marked
1899as having side effects. This is done through the use of the
1900'<tt>sideeffect</tt>' keyword, like so:
1901</p>
1902
1903<div class="doc_code">
1904<pre>
1905call void asm sideeffect "eieio", ""()
1906</pre>
1907</div>
1908
1909<p>TODO: The format of the asm and constraints string still need to be
1910documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]1911need to be documented). This is probably best done by reference to another
1912document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1913</p>
1914
1915</div>
1916
1917<!-- *********************************************************************** -->
1918<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1919<!-- *********************************************************************** -->
1920
1921<div class="doc_text">
1922
1923<p>The LLVM instruction set consists of several different
1924classifications of instructions: <a href="#terminators">terminator
1925instructions</a>, <a href="#binaryops">binary instructions</a>,
1926<a href="#bitwiseops">bitwise binary instructions</a>, <a
1927 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1928instructions</a>.</p>
1929
1930</div>
1931
1932<!-- ======================================================================= -->
1933<div class="doc_subsection"> <a name="terminators">Terminator
1934Instructions</a> </div>
1935
1936<div class="doc_text">
1937
1938<p>As mentioned <a href="#functionstructure">previously</a>, every
1939basic block in a program ends with a "Terminator" instruction, which
1940indicates which block should be executed after the current block is
1941finished. These terminator instructions typically yield a '<tt>void</tt>'
1942value: they produce control flow, not values (the one exception being
1943the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1944<p>There are six different terminator instructions: the '<a
1945 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1946instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1947the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1948 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1949 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1950
1951</div>
1952
1953<!-- _______________________________________________________________________ -->
1954<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1955Instruction</a> </div>
1956<div class="doc_text">
1957<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1958<pre>
1959 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]1960 ret void <i>; Return from void function</i>
1961</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1962
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1963<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1964
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1965<p>The '<tt>ret</tt>' instruction is used to return control flow (and
1966optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1967<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1968returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1969control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1970
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1971<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1972
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1973<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
1974the return value. The type of the return value must be a
1975'<a href="#t_firstclass">first class</a>' type.</p>
1976
1977<p>A function is not <a href="#wellformed">well formed</a> if
1978it it has a non-void return type and contains a '<tt>ret</tt>'
1979instruction with no return value or a return value with a type that
1980does not match its type, or if it has a void return type and contains
1981a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1982
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1983<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1984
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1985<p>When the '<tt>ret</tt>' instruction is executed, control flow
1986returns back to the calling function's context. If the caller is a "<a
1987 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1988the instruction after the call. If the caller was an "<a
1989 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1990at the beginning of the "normal" destination block. If the instruction
1991returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1992return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1993
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1994<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1995
1996<pre>
1997 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1998 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1999 ret { i32, i8 } { i32 4, i8 2 } <i>; Return an aggregate of values 4 and 2</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2000</pre>
2001</div>
2002<!-- _______________________________________________________________________ -->
2003<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
2004<div class="doc_text">
2005<h5>Syntax:</h5>
2006<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2007</pre>
2008<h5>Overview:</h5>
2009<p>The '<tt>br</tt>' instruction is used to cause control flow to
2010transfer to a different basic block in the current function. There are
2011two forms of this instruction, corresponding to a conditional branch
2012and an unconditional branch.</p>
2013<h5>Arguments:</h5>
2014<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2015single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2016unconditional form of the '<tt>br</tt>' instruction takes a single
2017'<tt>label</tt>' value as a target.</p>
2018<h5>Semantics:</h5>
2019<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2020argument is evaluated. If the value is <tt>true</tt>, control flows
2021to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2022control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2023<h5>Example:</h5>
2024<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
2025 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2026</div>
2027<!-- _______________________________________________________________________ -->
2028<div class="doc_subsubsection">
2029 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2030</div>
2031
2032<div class="doc_text">
2033<h5>Syntax:</h5>
2034
2035<pre>
2036 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2037</pre>
2038
2039<h5>Overview:</h5>
2040
2041<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2042several different places. It is a generalization of the '<tt>br</tt>'
2043instruction, allowing a branch to occur to one of many possible
2044destinations.</p>
2045
2046
2047<h5>Arguments:</h5>
2048
2049<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2050comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2051an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2052table is not allowed to contain duplicate constant entries.</p>
2053
2054<h5>Semantics:</h5>
2055
2056<p>The <tt>switch</tt> instruction specifies a table of values and
2057destinations. When the '<tt>switch</tt>' instruction is executed, this
2058table is searched for the given value. If the value is found, control flow is
2059transfered to the corresponding destination; otherwise, control flow is
2060transfered to the default destination.</p>
2061
2062<h5>Implementation:</h5>
2063
2064<p>Depending on properties of the target machine and the particular
2065<tt>switch</tt> instruction, this instruction may be code generated in different
2066ways. For example, it could be generated as a series of chained conditional
2067branches or with a lookup table.</p>
2068
2069<h5>Example:</h5>
2070
2071<pre>
2072 <i>; Emulate a conditional br instruction</i>
2073 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame^]2074 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2075
2076 <i>; Emulate an unconditional br instruction</i>
2077 switch i32 0, label %dest [ ]
2078
2079 <i>; Implement a jump table:</i>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame^]2080 switch i32 %val, label %otherwise [ i32 0, label %onzero
2081 i32 1, label %onone
2082 i32 2, label %ontwo ]
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2083</pre>
2084</div>
2085
2086<!-- _______________________________________________________________________ -->
2087<div class="doc_subsubsection">
2088 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2089</div>
2090
2091<div class="doc_text">
2092
2093<h5>Syntax:</h5>
2094
2095<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2096 &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]2097 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2098</pre>
2099
2100<h5>Overview:</h5>
2101
2102<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2103function, with the possibility of control flow transfer to either the
2104'<tt>normal</tt>' label or the
2105'<tt>exception</tt>' label. If the callee function returns with the
2106"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2107"normal" label. If the callee (or any indirect callees) returns with the "<a
2108href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2109continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2110
2111<h5>Arguments:</h5>
2112
2113<p>This instruction requires several arguments:</p>
2114
2115<ol>
2116 <li>
2117 The optional "cconv" marker indicates which <a href="#callingconv">calling
2118 convention</a> the call should use. If none is specified, the call defaults
2119 to using C calling conventions.
2120 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2121
2122 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2123 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2124 and '<tt>inreg</tt>' attributes are valid here.</li>
2125
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2126 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2127 function value being invoked. In most cases, this is a direct function
2128 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2129 an arbitrary pointer to function value.
2130 </li>
2131
2132 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2133 function to be invoked. </li>
2134
2135 <li>'<tt>function args</tt>': argument list whose types match the function
2136 signature argument types. If the function signature indicates the function
2137 accepts a variable number of arguments, the extra arguments can be
2138 specified. </li>
2139
2140 <li>'<tt>normal label</tt>': the label reached when the called function
2141 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2142
2143 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2144 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2145
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2146 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2147 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2148 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2149</ol>
2150
2151<h5>Semantics:</h5>
2152
2153<p>This instruction is designed to operate as a standard '<tt><a
2154href="#i_call">call</a></tt>' instruction in most regards. The primary
2155difference is that it establishes an association with a label, which is used by
2156the runtime library to unwind the stack.</p>
2157
2158<p>This instruction is used in languages with destructors to ensure that proper
2159cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2160exception. Additionally, this is important for implementation of
2161'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2162
2163<h5>Example:</h5>
2164<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2165 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2166 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2167 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2168 unwind label %TestCleanup <i>; {i32}:retval set</i>
2169</pre>
2170</div>
2171
2172
2173<!-- _______________________________________________________________________ -->
2174
2175<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2176Instruction</a> </div>
2177
2178<div class="doc_text">
2179
2180<h5>Syntax:</h5>
2181<pre>
2182 unwind
2183</pre>
2184
2185<h5>Overview:</h5>
2186
2187<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2188at the first callee in the dynamic call stack which used an <a
2189href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2190primarily used to implement exception handling.</p>
2191
2192<h5>Semantics:</h5>
2193
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2194<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2195immediately halt. The dynamic call stack is then searched for the first <a
2196href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2197execution continues at the "exceptional" destination block specified by the
2198<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2199dynamic call chain, undefined behavior results.</p>
2200</div>
2201
2202<!-- _______________________________________________________________________ -->
2203
2204<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2205Instruction</a> </div>
2206
2207<div class="doc_text">
2208
2209<h5>Syntax:</h5>
2210<pre>
2211 unreachable
2212</pre>
2213
2214<h5>Overview:</h5>
2215
2216<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2217instruction is used to inform the optimizer that a particular portion of the
2218code is not reachable. This can be used to indicate that the code after a
2219no-return function cannot be reached, and other facts.</p>
2220
2221<h5>Semantics:</h5>
2222
2223<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2224</div>
2225
2226
2227
2228<!-- ======================================================================= -->
2229<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2230<div class="doc_text">
2231<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2232program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2233produce a single value. The operands might represent
2234multiple 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]2235The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2236<p>There are several different binary operators:</p>
2237</div>
2238<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2239<div class="doc_subsubsection">
2240 <a name="i_add">'<tt>add</tt>' Instruction</a>
2241</div>
2242
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2243<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2245<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2246
2247<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2248 &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]2249</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2250
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2251<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2252
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2253<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2254
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2255<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2256
2257<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2258 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2259 <a href="#t_vector">vector</a> values. Both arguments must have identical
2260 types.</p>
2261
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2262<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2263
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2264<p>The value produced is the integer or floating point sum of the two
2265operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2266
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2267<p>If an integer sum has unsigned overflow, the result returned is the
2268mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2269the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2270
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2271<p>Because LLVM integers use a two's complement representation, this
2272instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2273
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2274<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2275
2276<pre>
2277 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2278</pre>
2279</div>
2280<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2281<div class="doc_subsubsection">
2282 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2283</div>
2284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2285<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2288
2289<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2290 &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]2291</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2292
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2293<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2294
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2295<p>The '<tt>sub</tt>' instruction returns the difference of its two
2296operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2297
2298<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2299'<tt>neg</tt>' instruction present in most other intermediate
2300representations.</p>
2301
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2302<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2303
2304<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2305 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2306 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2307 types.</p>
2308
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2309<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311<p>The value produced is the integer or floating point difference of
2312the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2313
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2314<p>If an integer difference has unsigned overflow, the result returned is the
2315mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2316the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2317
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2318<p>Because LLVM integers use a two's complement representation, this
2319instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2320
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2321<h5>Example:</h5>
2322<pre>
2323 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2324 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2325</pre>
2326</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2327
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2328<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2329<div class="doc_subsubsection">
2330 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2331</div>
2332
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2333<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2334
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2335<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2336<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]2337</pre>
2338<h5>Overview:</h5>
2339<p>The '<tt>mul</tt>' instruction returns the product of its two
2340operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2341
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2342<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2343
2344<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2345href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2346or <a href="#t_vector">vector</a> values. Both arguments must have identical
2347types.</p>
2348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2349<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2351<p>The value produced is the integer or floating point product of the
2352two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2353
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2354<p>If the result of an integer multiplication has unsigned overflow,
2355the result returned is the mathematical result modulo
23562<sup>n</sup>, where n is the bit width of the result.</p>
2357<p>Because LLVM integers use a two's complement representation, and the
2358result is the same width as the operands, this instruction returns the
2359correct result for both signed and unsigned integers. If a full product
2360(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2361should be sign-extended or zero-extended as appropriate to the
2362width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2363<h5>Example:</h5>
2364<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2365</pre>
2366</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2368<!-- _______________________________________________________________________ -->
2369<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2370</a></div>
2371<div class="doc_text">
2372<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2373<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]2374</pre>
2375<h5>Overview:</h5>
2376<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2377operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2379<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2380
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2381<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2382<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2383values. Both arguments must have identical types.</p>
2384
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2385<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2386
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2387<p>The value produced is the unsigned integer quotient of the two operands.</p>
2388<p>Note that unsigned integer division and signed integer division are distinct
2389operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2390<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2391<h5>Example:</h5>
2392<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2393</pre>
2394</div>
2395<!-- _______________________________________________________________________ -->
2396<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2397</a> </div>
2398<div class="doc_text">
2399<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2400<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2401 &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]2402</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2403
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2404<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2405
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2406<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2407operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2409<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2410
2411<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2412<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2413values. Both arguments must have identical types.</p>
2414
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2415<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2416<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]2417<p>Note that signed integer division and unsigned integer division are distinct
2418operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2419<p>Division by zero leads to undefined behavior. Overflow also leads to
2420undefined behavior; this is a rare case, but can occur, for example,
2421by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2422<h5>Example:</h5>
2423<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2424</pre>
2425</div>
2426<!-- _______________________________________________________________________ -->
2427<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2428Instruction</a> </div>
2429<div class="doc_text">
2430<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2431<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2432 &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]2433</pre>
2434<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2435
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2436<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2437operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2439<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2441<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2442<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2443of floating point values. Both arguments must have identical types.</p>
2444
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2445<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2446
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2447<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2448
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2449<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2450
2451<pre>
2452 &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]2453</pre>
2454</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2455
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2456<!-- _______________________________________________________________________ -->
2457<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2458</div>
2459<div class="doc_text">
2460<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2461<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]2462</pre>
2463<h5>Overview:</h5>
2464<p>The '<tt>urem</tt>' instruction returns the remainder from the
2465unsigned division of its two arguments.</p>
2466<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2467<p>The two arguments to the '<tt>urem</tt>' instruction must be
2468<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2469values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2470<h5>Semantics:</h5>
2471<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2472This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2473<p>Note that unsigned integer remainder and signed integer remainder are
2474distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2475<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2476<h5>Example:</h5>
2477<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2478</pre>
2479
2480</div>
2481<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2482<div class="doc_subsubsection">
2483 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2484</div>
2485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2486<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2488<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2489
2490<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2491 &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]2492</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2493
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2494<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2496<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2497signed division of its two operands. This instruction can also take
2498<a href="#t_vector">vector</a> versions of the values in which case
2499the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2504<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2505values. Both arguments must have identical types.</p>
2506
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2507<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2509<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2510has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2511operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2512a value. For more information about the difference, see <a
2513 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2514Math Forum</a>. For a table of how this is implemented in various languages,
2515please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2516Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2517<p>Note that signed integer remainder and unsigned integer remainder are
2518distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2519<p>Taking the remainder of a division by zero leads to undefined behavior.
2520Overflow also leads to undefined behavior; this is a rare case, but can occur,
2521for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2522(The remainder doesn't actually overflow, but this rule lets srem be
2523implemented using instructions that return both the result of the division
2524and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2525<h5>Example:</h5>
2526<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2527</pre>
2528
2529</div>
2530<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2531<div class="doc_subsubsection">
2532 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2533
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2534<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2535
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2536<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2537<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]2538</pre>
2539<h5>Overview:</h5>
2540<p>The '<tt>frem</tt>' instruction returns the remainder from the
2541division of its two operands.</p>
2542<h5>Arguments:</h5>
2543<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2544<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2545of floating point values. Both arguments must have identical types.</p>
2546
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2547<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2548
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2549<p>This instruction returns the <i>remainder</i> of a division.
2550The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2551
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2552<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2553
2554<pre>
2555 &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]2556</pre>
2557</div>
2558
2559<!-- ======================================================================= -->
2560<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2561Operations</a> </div>
2562<div class="doc_text">
2563<p>Bitwise binary operators are used to do various forms of
2564bit-twiddling in a program. They are generally very efficient
2565instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2566instructions. They require two operands of the same type, execute an operation on them,
2567and 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]2568</div>
2569
2570<!-- _______________________________________________________________________ -->
2571<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2572Instruction</a> </div>
2573<div class="doc_text">
2574<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2575<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]2576</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2579
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2580<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2581the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2584
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2585<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2586 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2587type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2590
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2591<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2592where 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]2593equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2594If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2595corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2596
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597<h5>Example:</h5><pre>
2598 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2599 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2600 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2601 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2602 &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]2603</pre>
2604</div>
2605<!-- _______________________________________________________________________ -->
2606<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2607Instruction</a> </div>
2608<div class="doc_text">
2609<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2610<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]2611</pre>
2612
2613<h5>Overview:</h5>
2614<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2615operand shifted to the right a specified number of bits with zero fill.</p>
2616
2617<h5>Arguments:</h5>
2618<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2619<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]2620type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2621
2622<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2623
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624<p>This instruction always performs a logical shift right operation. The most
2625significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2626shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2627the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2628vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2629amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2630
2631<h5>Example:</h5>
2632<pre>
2633 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2634 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2635 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2636 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2637 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2638 &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]2639</pre>
2640</div>
2641
2642<!-- _______________________________________________________________________ -->
2643<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2644Instruction</a> </div>
2645<div class="doc_text">
2646
2647<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2648<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]2649</pre>
2650
2651<h5>Overview:</h5>
2652<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2653operand shifted to the right a specified number of bits with sign extension.</p>
2654
2655<h5>Arguments:</h5>
2656<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2657<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]2658type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2659
2660<h5>Semantics:</h5>
2661<p>This instruction always performs an arithmetic shift right operation,
2662The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2663of <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]2664larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2665arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2666corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2667
2668<h5>Example:</h5>
2669<pre>
2670 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2671 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2672 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2673 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2674 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2675 &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]2676</pre>
2677</div>
2678
2679<!-- _______________________________________________________________________ -->
2680<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2681Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2682
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2683<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2686
2687<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2688 &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]2689</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2690
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2691<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2692
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2693<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2694its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2696<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2697
2698<p>The two arguments to the '<tt>and</tt>' instruction must be
2699<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2700values. Both arguments must have identical types.</p>
2701
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2702<h5>Semantics:</h5>
2703<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2704<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2705<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2706<table border="1" cellspacing="0" cellpadding="4">
2707 <tbody>
2708 <tr>
2709 <td>In0</td>
2710 <td>In1</td>
2711 <td>Out</td>
2712 </tr>
2713 <tr>
2714 <td>0</td>
2715 <td>0</td>
2716 <td>0</td>
2717 </tr>
2718 <tr>
2719 <td>0</td>
2720 <td>1</td>
2721 <td>0</td>
2722 </tr>
2723 <tr>
2724 <td>1</td>
2725 <td>0</td>
2726 <td>0</td>
2727 </tr>
2728 <tr>
2729 <td>1</td>
2730 <td>1</td>
2731 <td>1</td>
2732 </tr>
2733 </tbody>
2734</table>
2735</div>
2736<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2737<pre>
2738 &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]2739 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2740 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2741</pre>
2742</div>
2743<!-- _______________________________________________________________________ -->
2744<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2745<div class="doc_text">
2746<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2747<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]2748</pre>
2749<h5>Overview:</h5>
2750<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2751or of its two operands.</p>
2752<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2753
2754<p>The two arguments to the '<tt>or</tt>' instruction must be
2755<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2756values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2757<h5>Semantics:</h5>
2758<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2759<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2760<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2761<table border="1" cellspacing="0" cellpadding="4">
2762 <tbody>
2763 <tr>
2764 <td>In0</td>
2765 <td>In1</td>
2766 <td>Out</td>
2767 </tr>
2768 <tr>
2769 <td>0</td>
2770 <td>0</td>
2771 <td>0</td>
2772 </tr>
2773 <tr>
2774 <td>0</td>
2775 <td>1</td>
2776 <td>1</td>
2777 </tr>
2778 <tr>
2779 <td>1</td>
2780 <td>0</td>
2781 <td>1</td>
2782 </tr>
2783 <tr>
2784 <td>1</td>
2785 <td>1</td>
2786 <td>1</td>
2787 </tr>
2788 </tbody>
2789</table>
2790</div>
2791<h5>Example:</h5>
2792<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2793 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2794 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2795</pre>
2796</div>
2797<!-- _______________________________________________________________________ -->
2798<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2799Instruction</a> </div>
2800<div class="doc_text">
2801<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2802<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]2803</pre>
2804<h5>Overview:</h5>
2805<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2806or of its two operands. The <tt>xor</tt> is used to implement the
2807"one's complement" operation, which is the "~" operator in C.</p>
2808<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2809<p>The two arguments to the '<tt>xor</tt>' instruction must be
2810<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2811values. Both arguments must have identical types.</p>
2812
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2813<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2814
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2815<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2816<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2817<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2818<table border="1" cellspacing="0" cellpadding="4">
2819 <tbody>
2820 <tr>
2821 <td>In0</td>
2822 <td>In1</td>
2823 <td>Out</td>
2824 </tr>
2825 <tr>
2826 <td>0</td>
2827 <td>0</td>
2828 <td>0</td>
2829 </tr>
2830 <tr>
2831 <td>0</td>
2832 <td>1</td>
2833 <td>1</td>
2834 </tr>
2835 <tr>
2836 <td>1</td>
2837 <td>0</td>
2838 <td>1</td>
2839 </tr>
2840 <tr>
2841 <td>1</td>
2842 <td>1</td>
2843 <td>0</td>
2844 </tr>
2845 </tbody>
2846</table>
2847</div>
2848<p> </p>
2849<h5>Example:</h5>
2850<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2851 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2852 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2853 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2854</pre>
2855</div>
2856
2857<!-- ======================================================================= -->
2858<div class="doc_subsection">
2859 <a name="vectorops">Vector Operations</a>
2860</div>
2861
2862<div class="doc_text">
2863
2864<p>LLVM supports several instructions to represent vector operations in a
2865target-independent manner. These instructions cover the element-access and
2866vector-specific operations needed to process vectors effectively. While LLVM
2867does directly support these vector operations, many sophisticated algorithms
2868will want to use target-specific intrinsics to take full advantage of a specific
2869target.</p>
2870
2871</div>
2872
2873<!-- _______________________________________________________________________ -->
2874<div class="doc_subsubsection">
2875 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2876</div>
2877
2878<div class="doc_text">
2879
2880<h5>Syntax:</h5>
2881
2882<pre>
2883 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2884</pre>
2885
2886<h5>Overview:</h5>
2887
2888<p>
2889The '<tt>extractelement</tt>' instruction extracts a single scalar
2890element from a vector at a specified index.
2891</p>
2892
2893
2894<h5>Arguments:</h5>
2895
2896<p>
2897The first operand of an '<tt>extractelement</tt>' instruction is a
2898value of <a href="#t_vector">vector</a> type. The second operand is
2899an index indicating the position from which to extract the element.
2900The index may be a variable.</p>
2901
2902<h5>Semantics:</h5>
2903
2904<p>
2905The result is a scalar of the same type as the element type of
2906<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2907<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2908results are undefined.
2909</p>
2910
2911<h5>Example:</h5>
2912
2913<pre>
2914 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2915</pre>
2916</div>
2917
2918
2919<!-- _______________________________________________________________________ -->
2920<div class="doc_subsubsection">
2921 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2922</div>
2923
2924<div class="doc_text">
2925
2926<h5>Syntax:</h5>
2927
2928<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2929 &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]2930</pre>
2931
2932<h5>Overview:</h5>
2933
2934<p>
2935The '<tt>insertelement</tt>' instruction inserts a scalar
2936element into a vector at a specified index.
2937</p>
2938
2939
2940<h5>Arguments:</h5>
2941
2942<p>
2943The first operand of an '<tt>insertelement</tt>' instruction is a
2944value of <a href="#t_vector">vector</a> type. The second operand is a
2945scalar value whose type must equal the element type of the first
2946operand. The third operand is an index indicating the position at
2947which to insert the value. The index may be a variable.</p>
2948
2949<h5>Semantics:</h5>
2950
2951<p>
2952The result is a vector of the same type as <tt>val</tt>. Its
2953element values are those of <tt>val</tt> except at position
2954<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2955exceeds the length of <tt>val</tt>, the results are undefined.
2956</p>
2957
2958<h5>Example:</h5>
2959
2960<pre>
2961 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2962</pre>
2963</div>
2964
2965<!-- _______________________________________________________________________ -->
2966<div class="doc_subsubsection">
2967 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2968</div>
2969
2970<div class="doc_text">
2971
2972<h5>Syntax:</h5>
2973
2974<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2975 &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]2976</pre>
2977
2978<h5>Overview:</h5>
2979
2980<p>
2981The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2982from two input vectors, returning a vector with the same element type as
2983the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2984</p>
2985
2986<h5>Arguments:</h5>
2987
2988<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2989The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2990with types that match each other. The third argument is a shuffle mask whose
2991element type is always 'i32'. The result of the instruction is a vector whose
2992length is the same as the shuffle mask and whose element type is the same as
2993the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2994</p>
2995
2996<p>
2997The shuffle mask operand is required to be a constant vector with either
2998constant integer or undef values.
2999</p>
3000
3001<h5>Semantics:</h5>
3002
3003<p>
3004The elements of the two input vectors are numbered from left to right across
3005both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3006the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3007gets. The element selector may be undef (meaning "don't care") and the second
3008operand may be undef if performing a shuffle from only one vector.
3009</p>
3010
3011<h5>Example:</h5>
3012
3013<pre>
3014 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3015 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3016 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3017 &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]3018 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3019 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3020 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3021 &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]3022</pre>
3023</div>
3024
3025
3026<!-- ======================================================================= -->
3027<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3028 <a name="aggregateops">Aggregate Operations</a>
3029</div>
3030
3031<div class="doc_text">
3032
3033<p>LLVM supports several instructions for working with aggregate values.
3034</p>
3035
3036</div>
3037
3038<!-- _______________________________________________________________________ -->
3039<div class="doc_subsubsection">
3040 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3041</div>
3042
3043<div class="doc_text">
3044
3045<h5>Syntax:</h5>
3046
3047<pre>
3048 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3049</pre>
3050
3051<h5>Overview:</h5>
3052
3053<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3054The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3055or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3056</p>
3057
3058
3059<h5>Arguments:</h5>
3060
3061<p>
3062The first operand of an '<tt>extractvalue</tt>' instruction is a
3063value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3064type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3065in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3066'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3067</p>
3068
3069<h5>Semantics:</h5>
3070
3071<p>
3072The result is the value at the position in the aggregate specified by
3073the index operands.
3074</p>
3075
3076<h5>Example:</h5>
3077
3078<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3079 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3080</pre>
3081</div>
3082
3083
3084<!-- _______________________________________________________________________ -->
3085<div class="doc_subsubsection">
3086 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3087</div>
3088
3089<div class="doc_text">
3090
3091<h5>Syntax:</h5>
3092
3093<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3094 &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]3095</pre>
3096
3097<h5>Overview:</h5>
3098
3099<p>
3100The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3101into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3102</p>
3103
3104
3105<h5>Arguments:</h5>
3106
3107<p>
3108The first operand of an '<tt>insertvalue</tt>' instruction is a
3109value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3110The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3111The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3112indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3113indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3114'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3115The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3116by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3117</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3118
3119<h5>Semantics:</h5>
3120
3121<p>
3122The result is an aggregate of the same type as <tt>val</tt>. Its
3123value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3124specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3125</p>
3126
3127<h5>Example:</h5>
3128
3129<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3130 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3131</pre>
3132</div>
3133
3134
3135<!-- ======================================================================= -->
3136<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3137 <a name="memoryops">Memory Access and Addressing Operations</a>
3138</div>
3139
3140<div class="doc_text">
3141
3142<p>A key design point of an SSA-based representation is how it
3143represents memory. In LLVM, no memory locations are in SSA form, which
3144makes things very simple. This section describes how to read, write,
3145allocate, and free memory in LLVM.</p>
3146
3147</div>
3148
3149<!-- _______________________________________________________________________ -->
3150<div class="doc_subsubsection">
3151 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3152</div>
3153
3154<div class="doc_text">
3155
3156<h5>Syntax:</h5>
3157
3158<pre>
3159 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3160</pre>
3161
3162<h5>Overview:</h5>
3163
3164<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3165heap and returns a pointer to it. The object is always allocated in the generic
3166address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3167
3168<h5>Arguments:</h5>
3169
3170<p>The '<tt>malloc</tt>' instruction allocates
3171<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3172bytes of memory from the operating system and returns a pointer of the
3173appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3174number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3175If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3176be aligned to at least that boundary. If not specified, or if zero, the target can
3177choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3178
3179<p>'<tt>type</tt>' must be a sized type.</p>
3180
3181<h5>Semantics:</h5>
3182
3183<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3184a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3185result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3186
3187<h5>Example:</h5>
3188
3189<pre>
Dan Gohman01852382009-01-04 23:44:43 +0000[diff] [blame^]3190 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3191
3192 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3193 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3194 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3195 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3196 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3197</pre>
3198</div>
3199
3200<!-- _______________________________________________________________________ -->
3201<div class="doc_subsubsection">
3202 <a name="i_free">'<tt>free</tt>' Instruction</a>
3203</div>
3204
3205<div class="doc_text">
3206
3207<h5>Syntax:</h5>
3208
3209<pre>
3210 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3211</pre>
3212
3213<h5>Overview:</h5>
3214
3215<p>The '<tt>free</tt>' instruction returns memory back to the unused
3216memory heap to be reallocated in the future.</p>
3217
3218<h5>Arguments:</h5>
3219
3220<p>'<tt>value</tt>' shall be a pointer value that points to a value
3221that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3222instruction.</p>
3223
3224<h5>Semantics:</h5>
3225
3226<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3227after this instruction executes. If the pointer is null, the operation
3228is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3229
3230<h5>Example:</h5>
3231
3232<pre>
3233 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3234 free [4 x i8]* %array
3235</pre>
3236</div>
3237
3238<!-- _______________________________________________________________________ -->
3239<div class="doc_subsubsection">
3240 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3241</div>
3242
3243<div class="doc_text">
3244
3245<h5>Syntax:</h5>
3246
3247<pre>
3248 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3249</pre>
3250
3251<h5>Overview:</h5>
3252
3253<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3254currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3255returns to its caller. The object is always allocated in the generic address
3256space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3257
3258<h5>Arguments:</h5>
3259
3260<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3261bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3262appropriate type to the program. If "NumElements" is specified, it is the
3263number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3264If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3265to be aligned to at least that boundary. If not specified, or if zero, the target
3266can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3267
3268<p>'<tt>type</tt>' may be any sized type.</p>
3269
3270<h5>Semantics:</h5>
3271
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3272<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3273there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3274memory is automatically released when the function returns. The '<tt>alloca</tt>'
3275instruction is commonly used to represent automatic variables that must
3276have an address available. When the function returns (either with the <tt><a
3277 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]3278instructions), the memory is reclaimed. Allocating zero bytes
3279is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3280
3281<h5>Example:</h5>
3282
3283<pre>
3284 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3285 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3286 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3287 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3288</pre>
3289</div>
3290
3291<!-- _______________________________________________________________________ -->
3292<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3293Instruction</a> </div>
3294<div class="doc_text">
3295<h5>Syntax:</h5>
3296<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>
3297<h5>Overview:</h5>
3298<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3299<h5>Arguments:</h5>
3300<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3301address from which to load. The pointer must point to a <a
3302 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3303marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3304the number or order of execution of this <tt>load</tt> with other
3305volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3306instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3307<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3308The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3309(that is, the alignment of the memory address). A value of 0 or an
3310omitted "align" argument means that the operation has the preferential
3311alignment for the target. It is the responsibility of the code emitter
3312to ensure that the alignment information is correct. Overestimating
3313the alignment results in an undefined behavior. Underestimating the
3314alignment may produce less efficient code. An alignment of 1 is always
3315safe.
3316</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3317<h5>Semantics:</h5>
3318<p>The location of memory pointed to is loaded.</p>
3319<h5>Examples:</h5>
3320<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3321 <a
3322 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3323 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3324</pre>
3325</div>
3326<!-- _______________________________________________________________________ -->
3327<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3328Instruction</a> </div>
3329<div class="doc_text">
3330<h5>Syntax:</h5>
3331<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3332 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3333</pre>
3334<h5>Overview:</h5>
3335<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3336<h5>Arguments:</h5>
3337<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3338to 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]3339operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3340of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3342optimizer is not allowed to modify the number or order of execution of
3343this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3344 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3345<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3346The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3347(that is, the alignment of the memory address). A value of 0 or an
3348omitted "align" argument means that the operation has the preferential
3349alignment for the target. It is the responsibility of the code emitter
3350to ensure that the alignment information is correct. Overestimating
3351the alignment results in an undefined behavior. Underestimating the
3352alignment may produce less efficient code. An alignment of 1 is always
3353safe.
3354</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3355<h5>Semantics:</h5>
3356<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3357at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3358<h5>Example:</h5>
3359<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3360 store i32 3, i32* %ptr <i>; yields {void}</i>
3361 %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]3362</pre>
3363</div>
3364
3365<!-- _______________________________________________________________________ -->
3366<div class="doc_subsubsection">
3367 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3368</div>
3369
3370<div class="doc_text">
3371<h5>Syntax:</h5>
3372<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3373 &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]3374</pre>
3375
3376<h5>Overview:</h5>
3377
3378<p>
3379The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3380subelement of an aggregate data structure. It performs address calculation only
3381and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3382
3383<h5>Arguments:</h5>
3384
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3385<p>The first argument is always a pointer, and forms the basis of the
3386calculation. The remaining arguments are indices, that indicate which of the
3387elements of the aggregate object are indexed. The interpretation of each index
3388is dependent on the type being indexed into. The first index always indexes the
3389pointer value given as the first argument, the second index indexes a value of
3390the type pointed to (not necessarily the value directly pointed to, since the
3391first index can be non-zero), etc. The first type indexed into must be a pointer
3392value, subsequent types can be arrays, vectors and structs. Note that subsequent
3393types being indexed into can never be pointers, since that would require loading
3394the pointer before continuing calculation.</p>
3395
3396<p>The type of each index argument depends on the type it is indexing into.
3397When indexing into a (packed) structure, only <tt>i32</tt> integer
3398<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3399only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3400will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3401
3402<p>For example, let's consider a C code fragment and how it gets
3403compiled to LLVM:</p>
3404
3405<div class="doc_code">
3406<pre>
3407struct RT {
3408 char A;
3409 int B[10][20];
3410 char C;
3411};
3412struct ST {
3413 int X;
3414 double Y;
3415 struct RT Z;
3416};
3417
3418int *foo(struct ST *s) {
3419 return &amp;s[1].Z.B[5][13];
3420}
3421</pre>
3422</div>
3423
3424<p>The LLVM code generated by the GCC frontend is:</p>
3425
3426<div class="doc_code">
3427<pre>
3428%RT = type { i8 , [10 x [20 x i32]], i8 }
3429%ST = type { i32, double, %RT }
3430
3431define i32* %foo(%ST* %s) {
3432entry:
3433 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3434 ret i32* %reg
3435}
3436</pre>
3437</div>
3438
3439<h5>Semantics:</h5>
3440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3441<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3442type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3443}</tt>' type, a structure. The second index indexes into the third element of
3444the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3445i8 }</tt>' type, another structure. The third index indexes into the second
3446element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3447array. The two dimensions of the array are subscripted into, yielding an
3448'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3449to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3450
3451<p>Note that it is perfectly legal to index partially through a
3452structure, returning a pointer to an inner element. Because of this,
3453the LLVM code for the given testcase is equivalent to:</p>
3454
3455<pre>
3456 define i32* %foo(%ST* %s) {
3457 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3458 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3459 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3460 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3461 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3462 ret i32* %t5
3463 }
3464</pre>
3465
3466<p>Note that it is undefined to access an array out of bounds: array and
3467pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3468The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3469defined to be accessible as variable length arrays, which requires access
3470beyond the zero'th element.</p>
3471
3472<p>The getelementptr instruction is often confusing. For some more insight
3473into how it works, see <a href="GetElementPtr.html">the getelementptr
3474FAQ</a>.</p>
3475
3476<h5>Example:</h5>
3477
3478<pre>
3479 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3480 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3481 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3482 %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]3483 <i>; yields i8*:eptr</i>
3484 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3485</pre>
3486</div>
3487
3488<!-- ======================================================================= -->
3489<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3490</div>
3491<div class="doc_text">
3492<p>The instructions in this category are the conversion instructions (casting)
3493which all take a single operand and a type. They perform various bit conversions
3494on the operand.</p>
3495</div>
3496
3497<!-- _______________________________________________________________________ -->
3498<div class="doc_subsubsection">
3499 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3500</div>
3501<div class="doc_text">
3502
3503<h5>Syntax:</h5>
3504<pre>
3505 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3506</pre>
3507
3508<h5>Overview:</h5>
3509<p>
3510The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3511</p>
3512
3513<h5>Arguments:</h5>
3514<p>
3515The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3516be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3517and type of the result, which must be an <a href="#t_integer">integer</a>
3518type. The bit size of <tt>value</tt> must be larger than the bit size of
3519<tt>ty2</tt>. Equal sized types are not allowed.</p>
3520
3521<h5>Semantics:</h5>
3522<p>
3523The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3524and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3525larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3526It will always truncate bits.</p>
3527
3528<h5>Example:</h5>
3529<pre>
3530 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3531 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3532 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3533</pre>
3534</div>
3535
3536<!-- _______________________________________________________________________ -->
3537<div class="doc_subsubsection">
3538 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3539</div>
3540<div class="doc_text">
3541
3542<h5>Syntax:</h5>
3543<pre>
3544 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3545</pre>
3546
3547<h5>Overview:</h5>
3548<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3549<tt>ty2</tt>.</p>
3550
3551
3552<h5>Arguments:</h5>
3553<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3554<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3555also be of <a href="#t_integer">integer</a> type. The bit size of the
3556<tt>value</tt> must be smaller than the bit size of the destination type,
3557<tt>ty2</tt>.</p>
3558
3559<h5>Semantics:</h5>
3560<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3561bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3562
3563<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3564
3565<h5>Example:</h5>
3566<pre>
3567 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3568 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3569</pre>
3570</div>
3571
3572<!-- _______________________________________________________________________ -->
3573<div class="doc_subsubsection">
3574 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3575</div>
3576<div class="doc_text">
3577
3578<h5>Syntax:</h5>
3579<pre>
3580 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3581</pre>
3582
3583<h5>Overview:</h5>
3584<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3585
3586<h5>Arguments:</h5>
3587<p>
3588The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3589<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3590also be of <a href="#t_integer">integer</a> type. The bit size of the
3591<tt>value</tt> must be smaller than the bit size of the destination type,
3592<tt>ty2</tt>.</p>
3593
3594<h5>Semantics:</h5>
3595<p>
3596The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3597bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3598the type <tt>ty2</tt>.</p>
3599
3600<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3601
3602<h5>Example:</h5>
3603<pre>
3604 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3605 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3606</pre>
3607</div>
3608
3609<!-- _______________________________________________________________________ -->
3610<div class="doc_subsubsection">
3611 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3612</div>
3613
3614<div class="doc_text">
3615
3616<h5>Syntax:</h5>
3617
3618<pre>
3619 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3620</pre>
3621
3622<h5>Overview:</h5>
3623<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3624<tt>ty2</tt>.</p>
3625
3626
3627<h5>Arguments:</h5>
3628<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3629 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3630cast it to. The size of <tt>value</tt> must be larger than the size of
3631<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3632<i>no-op cast</i>.</p>
3633
3634<h5>Semantics:</h5>
3635<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3636<a href="#t_floating">floating point</a> type to a smaller
3637<a href="#t_floating">floating point</a> type. If the value cannot fit within
3638the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3639
3640<h5>Example:</h5>
3641<pre>
3642 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3643 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3644</pre>
3645</div>
3646
3647<!-- _______________________________________________________________________ -->
3648<div class="doc_subsubsection">
3649 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3650</div>
3651<div class="doc_text">
3652
3653<h5>Syntax:</h5>
3654<pre>
3655 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3656</pre>
3657
3658<h5>Overview:</h5>
3659<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3660floating point value.</p>
3661
3662<h5>Arguments:</h5>
3663<p>The '<tt>fpext</tt>' instruction takes a
3664<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3665and a <a href="#t_floating">floating point</a> type to cast it to. The source
3666type must be smaller than the destination type.</p>
3667
3668<h5>Semantics:</h5>
3669<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3670<a href="#t_floating">floating point</a> type to a larger
3671<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3672used to make a <i>no-op cast</i> because it always changes bits. Use
3673<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3674
3675<h5>Example:</h5>
3676<pre>
3677 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3678 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3679</pre>
3680</div>
3681
3682<!-- _______________________________________________________________________ -->
3683<div class="doc_subsubsection">
3684 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3685</div>
3686<div class="doc_text">
3687
3688<h5>Syntax:</h5>
3689<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3690 &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]3691</pre>
3692
3693<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3694<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3695unsigned integer equivalent of type <tt>ty2</tt>.
3696</p>
3697
3698<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3699<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]3700scalar or vector <a href="#t_floating">floating point</a> value, and a type
3701to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3702type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3703vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3704
3705<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3706<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3707<a href="#t_floating">floating point</a> operand into the nearest (rounding
3708towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3709the results are undefined.</p>
3710
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3711<h5>Example:</h5>
3712<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3713 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3714 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3715 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716</pre>
3717</div>
3718
3719<!-- _______________________________________________________________________ -->
3720<div class="doc_subsubsection">
3721 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3722</div>
3723<div class="doc_text">
3724
3725<h5>Syntax:</h5>
3726<pre>
3727 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3728</pre>
3729
3730<h5>Overview:</h5>
3731<p>The '<tt>fptosi</tt>' instruction converts
3732<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3733</p>
3734
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735<h5>Arguments:</h5>
3736<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]3737scalar or vector <a href="#t_floating">floating point</a> value, and a type
3738to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3739type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3740vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3741
3742<h5>Semantics:</h5>
3743<p>The '<tt>fptosi</tt>' instruction converts its
3744<a href="#t_floating">floating point</a> operand into the nearest (rounding
3745towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3746the results are undefined.</p>
3747
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3748<h5>Example:</h5>
3749<pre>
3750 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3751 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3752 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3753</pre>
3754</div>
3755
3756<!-- _______________________________________________________________________ -->
3757<div class="doc_subsubsection">
3758 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3759</div>
3760<div class="doc_text">
3761
3762<h5>Syntax:</h5>
3763<pre>
3764 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3765</pre>
3766
3767<h5>Overview:</h5>
3768<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3769integer and converts that value to the <tt>ty2</tt> type.</p>
3770
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3772<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3773scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3774to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3775type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3776floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3777
3778<h5>Semantics:</h5>
3779<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3780integer quantity and converts it to the corresponding floating point value. If
3781the value cannot fit in the floating point value, the results are undefined.</p>
3782
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3783<h5>Example:</h5>
3784<pre>
3785 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3786 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3787</pre>
3788</div>
3789
3790<!-- _______________________________________________________________________ -->
3791<div class="doc_subsubsection">
3792 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3793</div>
3794<div class="doc_text">
3795
3796<h5>Syntax:</h5>
3797<pre>
3798 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3799</pre>
3800
3801<h5>Overview:</h5>
3802<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3803integer and converts that value to the <tt>ty2</tt> type.</p>
3804
3805<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3806<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3807scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3808to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3809type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3810floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3811
3812<h5>Semantics:</h5>
3813<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3814integer quantity and converts it to the corresponding floating point value. If
3815the value cannot fit in the floating point value, the results are undefined.</p>
3816
3817<h5>Example:</h5>
3818<pre>
3819 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3820 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3821</pre>
3822</div>
3823
3824<!-- _______________________________________________________________________ -->
3825<div class="doc_subsubsection">
3826 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3827</div>
3828<div class="doc_text">
3829
3830<h5>Syntax:</h5>
3831<pre>
3832 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3833</pre>
3834
3835<h5>Overview:</h5>
3836<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3837the integer type <tt>ty2</tt>.</p>
3838
3839<h5>Arguments:</h5>
3840<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3841must 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]3842<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]3843
3844<h5>Semantics:</h5>
3845<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3846<tt>ty2</tt> by interpreting the pointer value as an integer and either
3847truncating or zero extending that value to the size of the integer type. If
3848<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3849<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3850are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3851change.</p>
3852
3853<h5>Example:</h5>
3854<pre>
3855 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3856 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3857</pre>
3858</div>
3859
3860<!-- _______________________________________________________________________ -->
3861<div class="doc_subsubsection">
3862 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3863</div>
3864<div class="doc_text">
3865
3866<h5>Syntax:</h5>
3867<pre>
3868 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3869</pre>
3870
3871<h5>Overview:</h5>
3872<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3873a pointer type, <tt>ty2</tt>.</p>
3874
3875<h5>Arguments:</h5>
3876<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3877value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3878<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3879
3880<h5>Semantics:</h5>
3881<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3882<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3883the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3884size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3885the size of a pointer then a zero extension is done. If they are the same size,
3886nothing is done (<i>no-op cast</i>).</p>
3887
3888<h5>Example:</h5>
3889<pre>
3890 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3891 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3892 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3893</pre>
3894</div>
3895
3896<!-- _______________________________________________________________________ -->
3897<div class="doc_subsubsection">
3898 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3899</div>
3900<div class="doc_text">
3901
3902<h5>Syntax:</h5>
3903<pre>
3904 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3905</pre>
3906
3907<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3908
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3909<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3910<tt>ty2</tt> without changing any bits.</p>
3911
3912<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3913
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3914<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3915a non-aggregate first class value, and a type to cast it to, which must also be
3916a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3917<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3918and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3919type is a pointer, the destination type must also be a pointer. This
3920instruction supports bitwise conversion of vectors to integers and to vectors
3921of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3922
3923<h5>Semantics:</h5>
3924<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3925<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3926this conversion. The conversion is done as if the <tt>value</tt> had been
3927stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3928converted to other pointer types with this instruction. To convert pointers to
3929other types, use the <a href="#i_inttoptr">inttoptr</a> or
3930<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3931
3932<h5>Example:</h5>
3933<pre>
3934 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3935 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3936 %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]3937</pre>
3938</div>
3939
3940<!-- ======================================================================= -->
3941<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3942<div class="doc_text">
3943<p>The instructions in this category are the "miscellaneous"
3944instructions, which defy better classification.</p>
3945</div>
3946
3947<!-- _______________________________________________________________________ -->
3948<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3949</div>
3950<div class="doc_text">
3951<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3952<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]3953</pre>
3954<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3955<p>The '<tt>icmp</tt>' instruction returns a boolean value or
3956a vector of boolean values based on comparison
3957of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3958<h5>Arguments:</h5>
3959<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3960the condition code indicating the kind of comparison to perform. It is not
3961a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3962</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3963<ol>
3964 <li><tt>eq</tt>: equal</li>
3965 <li><tt>ne</tt>: not equal </li>
3966 <li><tt>ugt</tt>: unsigned greater than</li>
3967 <li><tt>uge</tt>: unsigned greater or equal</li>
3968 <li><tt>ult</tt>: unsigned less than</li>
3969 <li><tt>ule</tt>: unsigned less or equal</li>
3970 <li><tt>sgt</tt>: signed greater than</li>
3971 <li><tt>sge</tt>: signed greater or equal</li>
3972 <li><tt>slt</tt>: signed less than</li>
3973 <li><tt>sle</tt>: signed less or equal</li>
3974</ol>
3975<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3976<a href="#t_pointer">pointer</a>
3977or integer <a href="#t_vector">vector</a> typed.
3978They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3980<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]3981the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3982yields 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]3983</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3984<ol>
3985 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3986 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3987 </li>
3988 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3989 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3991 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3992 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3993 <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]3994 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3995 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3996 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3997 <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]3998 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3999 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4001 <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]4002 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4003 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4004 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4005 <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]4006</ol>
4007<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4008values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4009<p>If the operands are integer vectors, then they are compared
4010element by element. The result is an <tt>i1</tt> vector with
4011the same number of elements as the values being compared.
4012Otherwise, the result is an <tt>i1</tt>.
4013</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4014
4015<h5>Example:</h5>
4016<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4017 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4018 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4019 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4020 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4021 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4022</pre>
4023</div>
4024
4025<!-- _______________________________________________________________________ -->
4026<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4027</div>
4028<div class="doc_text">
4029<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4030<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]4031</pre>
4032<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4033<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4034or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4035of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4036<p>
4037If the operands are floating point scalars, then the result
4038type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4039</p>
4040<p>If the operands are floating point vectors, then the result type
4041is a vector of boolean with the same number of elements as the
4042operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4043<h5>Arguments:</h5>
4044<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4045the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4046a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4047<ol>
4048 <li><tt>false</tt>: no comparison, always returns false</li>
4049 <li><tt>oeq</tt>: ordered and equal</li>
4050 <li><tt>ogt</tt>: ordered and greater than </li>
4051 <li><tt>oge</tt>: ordered and greater than or equal</li>
4052 <li><tt>olt</tt>: ordered and less than </li>
4053 <li><tt>ole</tt>: ordered and less than or equal</li>
4054 <li><tt>one</tt>: ordered and not equal</li>
4055 <li><tt>ord</tt>: ordered (no nans)</li>
4056 <li><tt>ueq</tt>: unordered or equal</li>
4057 <li><tt>ugt</tt>: unordered or greater than </li>
4058 <li><tt>uge</tt>: unordered or greater than or equal</li>
4059 <li><tt>ult</tt>: unordered or less than </li>
4060 <li><tt>ule</tt>: unordered or less than or equal</li>
4061 <li><tt>une</tt>: unordered or not equal</li>
4062 <li><tt>uno</tt>: unordered (either nans)</li>
4063 <li><tt>true</tt>: no comparison, always returns true</li>
4064</ol>
4065<p><i>Ordered</i> means that neither operand is a QNAN while
4066<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4067<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4068either a <a href="#t_floating">floating point</a> type
4069or a <a href="#t_vector">vector</a> of floating point type.
4070They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4071<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4072<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4073according to the condition code given as <tt>cond</tt>.
4074If the operands are vectors, then the vectors are compared
4075element by element.
4076Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4077always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078<ol>
4079 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4080 <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]4081 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4082 <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]4083 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084 <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]4085 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4086 <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]4087 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4088 <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]4089 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4090 <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]4091 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4092 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4093 <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]4094 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095 <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]4096 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4097 <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]4098 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4099 <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]4100 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4101 <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]4102 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4103 <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]4104 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4105 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4106 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4107</ol>
4108
4109<h5>Example:</h5>
4110<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]4111 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4112 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4113 &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]4114</pre>
4115</div>
4116
4117<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4118<div class="doc_subsubsection">
4119 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4120</div>
4121<div class="doc_text">
4122<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4123<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]4124</pre>
4125<h5>Overview:</h5>
4126<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4127element-wise comparison of its two integer vector operands.</p>
4128<h5>Arguments:</h5>
4129<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4130the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4131a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4132<ol>
4133 <li><tt>eq</tt>: equal</li>
4134 <li><tt>ne</tt>: not equal </li>
4135 <li><tt>ugt</tt>: unsigned greater than</li>
4136 <li><tt>uge</tt>: unsigned greater or equal</li>
4137 <li><tt>ult</tt>: unsigned less than</li>
4138 <li><tt>ule</tt>: unsigned less or equal</li>
4139 <li><tt>sgt</tt>: signed greater than</li>
4140 <li><tt>sge</tt>: signed greater or equal</li>
4141 <li><tt>slt</tt>: signed less than</li>
4142 <li><tt>sle</tt>: signed less or equal</li>
4143</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4144<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4145<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4146<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4147<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4148according to the condition code given as <tt>cond</tt>. The comparison yields a
4149<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4150identical type as the values being compared. The most significant bit in each
4151element is 1 if the element-wise comparison evaluates to true, and is 0
4152otherwise. All other bits of the result are undefined. The condition codes
4153are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4154instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4155
4156<h5>Example:</h5>
4157<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4158 &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>
4159 &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]4160</pre>
4161</div>
4162
4163<!-- _______________________________________________________________________ -->
4164<div class="doc_subsubsection">
4165 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4166</div>
4167<div class="doc_text">
4168<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4169<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]4170<h5>Overview:</h5>
4171<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4172element-wise comparison of its two floating point vector operands. The output
4173elements have the same width as the input elements.</p>
4174<h5>Arguments:</h5>
4175<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4176the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4177a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4178<ol>
4179 <li><tt>false</tt>: no comparison, always returns false</li>
4180 <li><tt>oeq</tt>: ordered and equal</li>
4181 <li><tt>ogt</tt>: ordered and greater than </li>
4182 <li><tt>oge</tt>: ordered and greater than or equal</li>
4183 <li><tt>olt</tt>: ordered and less than </li>
4184 <li><tt>ole</tt>: ordered and less than or equal</li>
4185 <li><tt>one</tt>: ordered and not equal</li>
4186 <li><tt>ord</tt>: ordered (no nans)</li>
4187 <li><tt>ueq</tt>: unordered or equal</li>
4188 <li><tt>ugt</tt>: unordered or greater than </li>
4189 <li><tt>uge</tt>: unordered or greater than or equal</li>
4190 <li><tt>ult</tt>: unordered or less than </li>
4191 <li><tt>ule</tt>: unordered or less than or equal</li>
4192 <li><tt>une</tt>: unordered or not equal</li>
4193 <li><tt>uno</tt>: unordered (either nans)</li>
4194 <li><tt>true</tt>: no comparison, always returns true</li>
4195</ol>
4196<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4197<a href="#t_floating">floating point</a> typed. They must also be identical
4198types.</p>
4199<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4200<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4201according to the condition code given as <tt>cond</tt>. The comparison yields a
4202<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4203an identical number of elements as the values being compared, and each element
4204having identical with to the width of the floating point elements. The most
4205significant bit in each element is 1 if the element-wise comparison evaluates to
4206true, and is 0 otherwise. All other bits of the result are undefined. The
4207condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4208<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4209
4210<h5>Example:</h5>
4211<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4212 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4213 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4214
4215 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4216 &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]4217</pre>
4218</div>
4219
4220<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4221<div class="doc_subsubsection">
4222 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4223</div>
4224
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4225<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4229<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4230<h5>Overview:</h5>
4231<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4232the SSA graph representing the function.</p>
4233<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4234
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4235<p>The type of the incoming values is specified with the first type
4236field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4237as arguments, with one pair for each predecessor basic block of the
4238current block. Only values of <a href="#t_firstclass">first class</a>
4239type may be used as the value arguments to the PHI node. Only labels
4240may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4242<p>There must be no non-phi instructions between the start of a basic
4243block and the PHI instructions: i.e. PHI instructions must be first in
4244a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4247
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4248<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4249specified by the pair corresponding to the predecessor basic block that executed
4250just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4251
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4252<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4253<pre>
4254Loop: ; Infinite loop that counts from 0 on up...
4255 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4256 %nextindvar = add i32 %indvar, 1
4257 br label %Loop
4258</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4259</div>
4260
4261<!-- _______________________________________________________________________ -->
4262<div class="doc_subsubsection">
4263 <a name="i_select">'<tt>select</tt>' Instruction</a>
4264</div>
4265
4266<div class="doc_text">
4267
4268<h5>Syntax:</h5>
4269
4270<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4271 &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>
4272
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4273 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4274</pre>
4275
4276<h5>Overview:</h5>
4277
4278<p>
4279The '<tt>select</tt>' instruction is used to choose one value based on a
4280condition, without branching.
4281</p>
4282
4283
4284<h5>Arguments:</h5>
4285
4286<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4287The '<tt>select</tt>' instruction requires an 'i1' value or
4288a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4289condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4290type. If the val1/val2 are vectors and
4291the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4292individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4293</p>
4294
4295<h5>Semantics:</h5>
4296
4297<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4298If 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]4299value argument; otherwise, it returns the second value argument.
4300</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4301<p>
4302If the condition is a vector of i1, then the value arguments must
4303be vectors of the same size, and the selection is done element
4304by element.
4305</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4306
4307<h5>Example:</h5>
4308
4309<pre>
4310 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4311</pre>
4312</div>
4313
4314
4315<!-- _______________________________________________________________________ -->
4316<div class="doc_subsubsection">
4317 <a name="i_call">'<tt>call</tt>' Instruction</a>
4318</div>
4319
4320<div class="doc_text">
4321
4322<h5>Syntax:</h5>
4323<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4324 &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]4325</pre>
4326
4327<h5>Overview:</h5>
4328
4329<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4330
4331<h5>Arguments:</h5>
4332
4333<p>This instruction requires several arguments:</p>
4334
4335<ol>
4336 <li>
4337 <p>The optional "tail" marker indicates whether the callee function accesses
4338 any allocas or varargs in the caller. If the "tail" marker is present, the
4339 function call is eligible for tail call optimization. Note that calls may
4340 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4341 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4342 </li>
4343 <li>
4344 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4345 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4346 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4347 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4348
4349 <li>
4350 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4351 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4352 and '<tt>inreg</tt>' attributes are valid here.</p>
4353 </li>
4354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4355 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4356 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4357 the type of the return value. Functions that return no value are marked
4358 <tt><a href="#t_void">void</a></tt>.</p>
4359 </li>
4360 <li>
4361 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4362 value being invoked. The argument types must match the types implied by
4363 this signature. This type can be omitted if the function is not varargs
4364 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4365 </li>
4366 <li>
4367 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4368 be invoked. In most cases, this is a direct function invocation, but
4369 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4370 to function value.</p>
4371 </li>
4372 <li>
4373 <p>'<tt>function args</tt>': argument list whose types match the
4374 function signature argument types. All arguments must be of
4375 <a href="#t_firstclass">first class</a> type. If the function signature
4376 indicates the function accepts a variable number of arguments, the extra
4377 arguments can be specified.</p>
4378 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4379 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4380 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4381 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4382 '<tt>readnone</tt>' attributes are valid here.</p>
4383 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4384</ol>
4385
4386<h5>Semantics:</h5>
4387
4388<p>The '<tt>call</tt>' instruction is used to cause control flow to
4389transfer to a specified function, with its incoming arguments bound to
4390the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4391instruction in the called function, control flow continues with the
4392instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4393function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4394
4395<h5>Example:</h5>
4396
4397<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4398 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4399 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4400 %X = tail call i32 @foo() <i>; yields i32</i>
4401 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4402 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4403
4404 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4405 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4406 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4407 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4408 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4409 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4410</pre>
4411
4412</div>
4413
4414<!-- _______________________________________________________________________ -->
4415<div class="doc_subsubsection">
4416 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4417</div>
4418
4419<div class="doc_text">
4420
4421<h5>Syntax:</h5>
4422
4423<pre>
4424 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4425</pre>
4426
4427<h5>Overview:</h5>
4428
4429<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4430the "variable argument" area of a function call. It is used to implement the
4431<tt>va_arg</tt> macro in C.</p>
4432
4433<h5>Arguments:</h5>
4434
4435<p>This instruction takes a <tt>va_list*</tt> value and the type of
4436the argument. It returns a value of the specified argument type and
4437increments the <tt>va_list</tt> to point to the next argument. The
4438actual type of <tt>va_list</tt> is target specific.</p>
4439
4440<h5>Semantics:</h5>
4441
4442<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4443type from the specified <tt>va_list</tt> and causes the
4444<tt>va_list</tt> to point to the next argument. For more information,
4445see the variable argument handling <a href="#int_varargs">Intrinsic
4446Functions</a>.</p>
4447
4448<p>It is legal for this instruction to be called in a function which does not
4449take a variable number of arguments, for example, the <tt>vfprintf</tt>
4450function.</p>
4451
4452<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4453href="#intrinsics">intrinsic function</a> because it takes a type as an
4454argument.</p>
4455
4456<h5>Example:</h5>
4457
4458<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4459
4460</div>
4461
4462<!-- *********************************************************************** -->
4463<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4464<!-- *********************************************************************** -->
4465
4466<div class="doc_text">
4467
4468<p>LLVM supports the notion of an "intrinsic function". These functions have
4469well known names and semantics and are required to follow certain restrictions.
4470Overall, these intrinsics represent an extension mechanism for the LLVM
4471language that does not require changing all of the transformations in LLVM when
4472adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4473
4474<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4475prefix is reserved in LLVM for intrinsic names; thus, function names may not
4476begin with this prefix. Intrinsic functions must always be external functions:
4477you cannot define the body of intrinsic functions. Intrinsic functions may
4478only be used in call or invoke instructions: it is illegal to take the address
4479of an intrinsic function. Additionally, because intrinsic functions are part
4480of the LLVM language, it is required if any are added that they be documented
4481here.</p>
4482
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4483<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4484a family of functions that perform the same operation but on different data
4485types. Because LLVM can represent over 8 million different integer types,
4486overloading is used commonly to allow an intrinsic function to operate on any
4487integer type. One or more of the argument types or the result type can be
4488overloaded to accept any integer type. Argument types may also be defined as
4489exactly matching a previous argument's type or the result type. This allows an
4490intrinsic function which accepts multiple arguments, but needs all of them to
4491be of the same type, to only be overloaded with respect to a single argument or
4492the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4493
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4494<p>Overloaded intrinsics will have the names of its overloaded argument types
4495encoded into its function name, each preceded by a period. Only those types
4496which are overloaded result in a name suffix. Arguments whose type is matched
4497against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4498take an integer of any width and returns an integer of exactly the same integer
4499width. This leads to a family of functions such as
4500<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4501Only one type, the return type, is overloaded, and only one type suffix is
4502required. Because the argument's type is matched against the return type, it
4503does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4504
4505<p>To learn how to add an intrinsic function, please see the
4506<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4507</p>
4508
4509</div>
4510
4511<!-- ======================================================================= -->
4512<div class="doc_subsection">
4513 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4514</div>
4515
4516<div class="doc_text">
4517
4518<p>Variable argument support is defined in LLVM with the <a
4519 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4520intrinsic functions. These functions are related to the similarly
4521named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4522
4523<p>All of these functions operate on arguments that use a
4524target-specific value type "<tt>va_list</tt>". The LLVM assembly
4525language reference manual does not define what this type is, so all
4526transformations should be prepared to handle these functions regardless of
4527the type used.</p>
4528
4529<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4530instruction and the variable argument handling intrinsic functions are
4531used.</p>
4532
4533<div class="doc_code">
4534<pre>
4535define i32 @test(i32 %X, ...) {
4536 ; Initialize variable argument processing
4537 %ap = alloca i8*
4538 %ap2 = bitcast i8** %ap to i8*
4539 call void @llvm.va_start(i8* %ap2)
4540
4541 ; Read a single integer argument
4542 %tmp = va_arg i8** %ap, i32
4543
4544 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4545 %aq = alloca i8*
4546 %aq2 = bitcast i8** %aq to i8*
4547 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4548 call void @llvm.va_end(i8* %aq2)
4549
4550 ; Stop processing of arguments.
4551 call void @llvm.va_end(i8* %ap2)
4552 ret i32 %tmp
4553}
4554
4555declare void @llvm.va_start(i8*)
4556declare void @llvm.va_copy(i8*, i8*)
4557declare void @llvm.va_end(i8*)
4558</pre>
4559</div>
4560
4561</div>
4562
4563<!-- _______________________________________________________________________ -->
4564<div class="doc_subsubsection">
4565 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4566</div>
4567
4568
4569<div class="doc_text">
4570<h5>Syntax:</h5>
4571<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4572<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4573<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4574<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4575href="#i_va_arg">va_arg</a></tt>.</p>
4576
4577<h5>Arguments:</h5>
4578
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4579<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]4580
4581<h5>Semantics:</h5>
4582
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4583<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]4584macro available in C. In a target-dependent way, it initializes the
4585<tt>va_list</tt> element to which the argument points, so that the next call to
4586<tt>va_arg</tt> will produce the first variable argument passed to the function.
4587Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4588last argument of the function as the compiler can figure that out.</p>
4589
4590</div>
4591
4592<!-- _______________________________________________________________________ -->
4593<div class="doc_subsubsection">
4594 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4595</div>
4596
4597<div class="doc_text">
4598<h5>Syntax:</h5>
4599<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4600<h5>Overview:</h5>
4601
4602<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4603which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4604or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4605
4606<h5>Arguments:</h5>
4607
4608<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4609
4610<h5>Semantics:</h5>
4611
4612<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4613macro available in C. In a target-dependent way, it destroys the
4614<tt>va_list</tt> element to which the argument points. Calls to <a
4615href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4616<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4617<tt>llvm.va_end</tt>.</p>
4618
4619</div>
4620
4621<!-- _______________________________________________________________________ -->
4622<div class="doc_subsubsection">
4623 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4624</div>
4625
4626<div class="doc_text">
4627
4628<h5>Syntax:</h5>
4629
4630<pre>
4631 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4632</pre>
4633
4634<h5>Overview:</h5>
4635
4636<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4637from the source argument list to the destination argument list.</p>
4638
4639<h5>Arguments:</h5>
4640
4641<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4642The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4643
4644
4645<h5>Semantics:</h5>
4646
4647<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4648macro available in C. In a target-dependent way, it copies the source
4649<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4650intrinsic is necessary because the <tt><a href="#int_va_start">
4651llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4652example, memory allocation.</p>
4653
4654</div>
4655
4656<!-- ======================================================================= -->
4657<div class="doc_subsection">
4658 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4659</div>
4660
4661<div class="doc_text">
4662
4663<p>
4664LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4665Collection</a> (GC) requires the implementation and generation of these
4666intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4667These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4668stack</a>, as well as garbage collector implementations that require <a
4669href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4670Front-ends for type-safe garbage collected languages should generate these
4671intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4672href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4673</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4674
4675<p>The garbage collection intrinsics only operate on objects in the generic
4676 address space (address space zero).</p>
4677
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4678</div>
4679
4680<!-- _______________________________________________________________________ -->
4681<div class="doc_subsubsection">
4682 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4683</div>
4684
4685<div class="doc_text">
4686
4687<h5>Syntax:</h5>
4688
4689<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4690 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4691</pre>
4692
4693<h5>Overview:</h5>
4694
4695<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4696the code generator, and allows some metadata to be associated with it.</p>
4697
4698<h5>Arguments:</h5>
4699
4700<p>The first argument specifies the address of a stack object that contains the
4701root pointer. The second pointer (which must be either a constant or a global
4702value address) contains the meta-data to be associated with the root.</p>
4703
4704<h5>Semantics:</h5>
4705
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4706<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]4707location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4708the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4709intrinsic may only be used in a function which <a href="#gc">specifies a GC
4710algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4711
4712</div>
4713
4714
4715<!-- _______________________________________________________________________ -->
4716<div class="doc_subsubsection">
4717 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4718</div>
4719
4720<div class="doc_text">
4721
4722<h5>Syntax:</h5>
4723
4724<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4725 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4726</pre>
4727
4728<h5>Overview:</h5>
4729
4730<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4731locations, allowing garbage collector implementations that require read
4732barriers.</p>
4733
4734<h5>Arguments:</h5>
4735
4736<p>The second argument is the address to read from, which should be an address
4737allocated from the garbage collector. The first object is a pointer to the
4738start of the referenced object, if needed by the language runtime (otherwise
4739null).</p>
4740
4741<h5>Semantics:</h5>
4742
4743<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4744instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4745garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4746may only be used in a function which <a href="#gc">specifies a GC
4747algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4748
4749</div>
4750
4751
4752<!-- _______________________________________________________________________ -->
4753<div class="doc_subsubsection">
4754 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4755</div>
4756
4757<div class="doc_text">
4758
4759<h5>Syntax:</h5>
4760
4761<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4762 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4763</pre>
4764
4765<h5>Overview:</h5>
4766
4767<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4768locations, allowing garbage collector implementations that require write
4769barriers (such as generational or reference counting collectors).</p>
4770
4771<h5>Arguments:</h5>
4772
4773<p>The first argument is the reference to store, the second is the start of the
4774object to store it to, and the third is the address of the field of Obj to
4775store to. If the runtime does not require a pointer to the object, Obj may be
4776null.</p>
4777
4778<h5>Semantics:</h5>
4779
4780<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4781instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4782garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4783may only be used in a function which <a href="#gc">specifies a GC
4784algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4785
4786</div>
4787
4788
4789
4790<!-- ======================================================================= -->
4791<div class="doc_subsection">
4792 <a name="int_codegen">Code Generator Intrinsics</a>
4793</div>
4794
4795<div class="doc_text">
4796<p>
4797These intrinsics are provided by LLVM to expose special features that may only
4798be implemented with code generator support.
4799</p>
4800
4801</div>
4802
4803<!-- _______________________________________________________________________ -->
4804<div class="doc_subsubsection">
4805 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4806</div>
4807
4808<div class="doc_text">
4809
4810<h5>Syntax:</h5>
4811<pre>
4812 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4813</pre>
4814
4815<h5>Overview:</h5>
4816
4817<p>
4818The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4819target-specific value indicating the return address of the current function
4820or one of its callers.
4821</p>
4822
4823<h5>Arguments:</h5>
4824
4825<p>
4826The argument to this intrinsic indicates which function to return the address
4827for. Zero indicates the calling function, one indicates its caller, etc. The
4828argument is <b>required</b> to be a constant integer value.
4829</p>
4830
4831<h5>Semantics:</h5>
4832
4833<p>
4834The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4835the return address of the specified call frame, or zero if it cannot be
4836identified. The value returned by this intrinsic is likely to be incorrect or 0
4837for arguments other than zero, so it should only be used for debugging purposes.
4838</p>
4839
4840<p>
4841Note that calling this intrinsic does not prevent function inlining or other
4842aggressive transformations, so the value returned may not be that of the obvious
4843source-language caller.
4844</p>
4845</div>
4846
4847
4848<!-- _______________________________________________________________________ -->
4849<div class="doc_subsubsection">
4850 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4851</div>
4852
4853<div class="doc_text">
4854
4855<h5>Syntax:</h5>
4856<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4857 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4858</pre>
4859
4860<h5>Overview:</h5>
4861
4862<p>
4863The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4864target-specific frame pointer value for the specified stack frame.
4865</p>
4866
4867<h5>Arguments:</h5>
4868
4869<p>
4870The argument to this intrinsic indicates which function to return the frame
4871pointer for. Zero indicates the calling function, one indicates its caller,
4872etc. The argument is <b>required</b> to be a constant integer value.
4873</p>
4874
4875<h5>Semantics:</h5>
4876
4877<p>
4878The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4879the frame address of the specified call frame, or zero if it cannot be
4880identified. The value returned by this intrinsic is likely to be incorrect or 0
4881for arguments other than zero, so it should only be used for debugging purposes.
4882</p>
4883
4884<p>
4885Note that calling this intrinsic does not prevent function inlining or other
4886aggressive transformations, so the value returned may not be that of the obvious
4887source-language caller.
4888</p>
4889</div>
4890
4891<!-- _______________________________________________________________________ -->
4892<div class="doc_subsubsection">
4893 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4894</div>
4895
4896<div class="doc_text">
4897
4898<h5>Syntax:</h5>
4899<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4900 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4901</pre>
4902
4903<h5>Overview:</h5>
4904
4905<p>
4906The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4907the function stack, for use with <a href="#int_stackrestore">
4908<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4909features like scoped automatic variable sized arrays in C99.
4910</p>
4911
4912<h5>Semantics:</h5>
4913
4914<p>
4915This intrinsic returns a opaque pointer value that can be passed to <a
4916href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4917<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4918<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4919state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4920practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4921that were allocated after the <tt>llvm.stacksave</tt> was executed.
4922</p>
4923
4924</div>
4925
4926<!-- _______________________________________________________________________ -->
4927<div class="doc_subsubsection">
4928 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4929</div>
4930
4931<div class="doc_text">
4932
4933<h5>Syntax:</h5>
4934<pre>
4935 declare void @llvm.stackrestore(i8 * %ptr)
4936</pre>
4937
4938<h5>Overview:</h5>
4939
4940<p>
4941The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4942the function stack to the state it was in when the corresponding <a
4943href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4944useful for implementing language features like scoped automatic variable sized
4945arrays in C99.
4946</p>
4947
4948<h5>Semantics:</h5>
4949
4950<p>
4951See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4952</p>
4953
4954</div>
4955
4956
4957<!-- _______________________________________________________________________ -->
4958<div class="doc_subsubsection">
4959 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4960</div>
4961
4962<div class="doc_text">
4963
4964<h5>Syntax:</h5>
4965<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4966 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]4967</pre>
4968
4969<h5>Overview:</h5>
4970
4971
4972<p>
4973The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4974a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4975no
4976effect on the behavior of the program but can change its performance
4977characteristics.
4978</p>
4979
4980<h5>Arguments:</h5>
4981
4982<p>
4983<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4984determining if the fetch should be for a read (0) or write (1), and
4985<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4986locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4987<tt>locality</tt> arguments must be constant integers.
4988</p>
4989
4990<h5>Semantics:</h5>
4991
4992<p>
4993This intrinsic does not modify the behavior of the program. In particular,
4994prefetches cannot trap and do not produce a value. On targets that support this
4995intrinsic, the prefetch can provide hints to the processor cache for better
4996performance.
4997</p>
4998
4999</div>
5000
5001<!-- _______________________________________________________________________ -->
5002<div class="doc_subsubsection">
5003 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
5004</div>
5005
5006<div class="doc_text">
5007
5008<h5>Syntax:</h5>
5009<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5010 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5011</pre>
5012
5013<h5>Overview:</h5>
5014
5015
5016<p>
5017The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5018(PC) in a region of
5019code to simulators and other tools. The method is target specific, but it is
5020expected that the marker will use exported symbols to transmit the PC of the
5021marker.
5022The marker makes no guarantees that it will remain with any specific instruction
5023after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5024optimizations. The intended use is to be inserted after optimizations to allow
5025correlations of simulation runs.
5026</p>
5027
5028<h5>Arguments:</h5>
5029
5030<p>
5031<tt>id</tt> is a numerical id identifying the marker.
5032</p>
5033
5034<h5>Semantics:</h5>
5035
5036<p>
5037This intrinsic does not modify the behavior of the program. Backends that do not
5038support this intrinisic may ignore it.
5039</p>
5040
5041</div>
5042
5043<!-- _______________________________________________________________________ -->
5044<div class="doc_subsubsection">
5045 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5046</div>
5047
5048<div class="doc_text">
5049
5050<h5>Syntax:</h5>
5051<pre>
5052 declare i64 @llvm.readcyclecounter( )
5053</pre>
5054
5055<h5>Overview:</h5>
5056
5057
5058<p>
5059The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5060counter register (or similar low latency, high accuracy clocks) on those targets
5061that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5062As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5063should only be used for small timings.
5064</p>
5065
5066<h5>Semantics:</h5>
5067
5068<p>
5069When directly supported, reading the cycle counter should not modify any memory.
5070Implementations are allowed to either return a application specific value or a
5071system wide value. On backends without support, this is lowered to a constant 0.
5072</p>
5073
5074</div>
5075
5076<!-- ======================================================================= -->
5077<div class="doc_subsection">
5078 <a name="int_libc">Standard C Library Intrinsics</a>
5079</div>
5080
5081<div class="doc_text">
5082<p>
5083LLVM provides intrinsics for a few important standard C library functions.
5084These intrinsics allow source-language front-ends to pass information about the
5085alignment of the pointer arguments to the code generator, providing opportunity
5086for more efficient code generation.
5087</p>
5088
5089</div>
5090
5091<!-- _______________________________________________________________________ -->
5092<div class="doc_subsubsection">
5093 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5094</div>
5095
5096<div class="doc_text">
5097
5098<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5099<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5100width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5101<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5102 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5103 i8 &lt;len&gt;, i32 &lt;align&gt;)
5104 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5105 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5106 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5107 i32 &lt;len&gt;, i32 &lt;align&gt;)
5108 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5109 i64 &lt;len&gt;, i32 &lt;align&gt;)
5110</pre>
5111
5112<h5>Overview:</h5>
5113
5114<p>
5115The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5116location to the destination location.
5117</p>
5118
5119<p>
5120Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5121intrinsics do not return a value, and takes an extra alignment argument.
5122</p>
5123
5124<h5>Arguments:</h5>
5125
5126<p>
5127The first argument is a pointer to the destination, the second is a pointer to
5128the source. The third argument is an integer argument
5129specifying the number of bytes to copy, and the fourth argument is the alignment
5130of the source and destination locations.
5131</p>
5132
5133<p>
5134If the call to this intrinisic has an alignment value that is not 0 or 1, then
5135the caller guarantees that both the source and destination pointers are aligned
5136to that boundary.
5137</p>
5138
5139<h5>Semantics:</h5>
5140
5141<p>
5142The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5143location to the destination location, which are not allowed to overlap. It
5144copies "len" bytes of memory over. If the argument is known to be aligned to
5145some boundary, this can be specified as the fourth argument, otherwise it should
5146be set to 0 or 1.
5147</p>
5148</div>
5149
5150
5151<!-- _______________________________________________________________________ -->
5152<div class="doc_subsubsection">
5153 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5154</div>
5155
5156<div class="doc_text">
5157
5158<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5159<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5160width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5161<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5162 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5163 i8 &lt;len&gt;, i32 &lt;align&gt;)
5164 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5165 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5166 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5167 i32 &lt;len&gt;, i32 &lt;align&gt;)
5168 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5169 i64 &lt;len&gt;, i32 &lt;align&gt;)
5170</pre>
5171
5172<h5>Overview:</h5>
5173
5174<p>
5175The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5176location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5177'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5178</p>
5179
5180<p>
5181Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5182intrinsics do not return a value, and takes an extra alignment argument.
5183</p>
5184
5185<h5>Arguments:</h5>
5186
5187<p>
5188The first argument is a pointer to the destination, the second is a pointer to
5189the source. The third argument is an integer argument
5190specifying the number of bytes to copy, and the fourth argument is the alignment
5191of the source and destination locations.
5192</p>
5193
5194<p>
5195If the call to this intrinisic has an alignment value that is not 0 or 1, then
5196the caller guarantees that the source and destination pointers are aligned to
5197that boundary.
5198</p>
5199
5200<h5>Semantics:</h5>
5201
5202<p>
5203The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5204location to the destination location, which may overlap. It
5205copies "len" bytes of memory over. If the argument is known to be aligned to
5206some boundary, this can be specified as the fourth argument, otherwise it should
5207be set to 0 or 1.
5208</p>
5209</div>
5210
5211
5212<!-- _______________________________________________________________________ -->
5213<div class="doc_subsubsection">
5214 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5215</div>
5216
5217<div class="doc_text">
5218
5219<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5220<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5221width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5222<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5223 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5224 i8 &lt;len&gt;, i32 &lt;align&gt;)
5225 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5226 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5227 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5228 i32 &lt;len&gt;, i32 &lt;align&gt;)
5229 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5230 i64 &lt;len&gt;, i32 &lt;align&gt;)
5231</pre>
5232
5233<h5>Overview:</h5>
5234
5235<p>
5236The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5237byte value.
5238</p>
5239
5240<p>
5241Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5242does not return a value, and takes an extra alignment argument.
5243</p>
5244
5245<h5>Arguments:</h5>
5246
5247<p>
5248The first argument is a pointer to the destination to fill, the second is the
5249byte value to fill it with, the third argument is an integer
5250argument specifying the number of bytes to fill, and the fourth argument is the
5251known alignment of destination location.
5252</p>
5253
5254<p>
5255If the call to this intrinisic has an alignment value that is not 0 or 1, then
5256the caller guarantees that the destination pointer is aligned to that boundary.
5257</p>
5258
5259<h5>Semantics:</h5>
5260
5261<p>
5262The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5263the
5264destination location. If the argument is known to be aligned to some boundary,
5265this can be specified as the fourth argument, otherwise it should be set to 0 or
52661.
5267</p>
5268</div>
5269
5270
5271<!-- _______________________________________________________________________ -->
5272<div class="doc_subsubsection">
5273 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5274</div>
5275
5276<div class="doc_text">
5277
5278<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5279<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]5280floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5281types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5282<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5283 declare float @llvm.sqrt.f32(float %Val)
5284 declare double @llvm.sqrt.f64(double %Val)
5285 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5286 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5287 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5288</pre>
5289
5290<h5>Overview:</h5>
5291
5292<p>
5293The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5294returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5295<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5296negative numbers other than -0.0 (which allows for better optimization, because
5297there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5298defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5299</p>
5300
5301<h5>Arguments:</h5>
5302
5303<p>
5304The argument and return value are floating point numbers of the same type.
5305</p>
5306
5307<h5>Semantics:</h5>
5308
5309<p>
5310This function returns the sqrt of the specified operand if it is a nonnegative
5311floating point number.
5312</p>
5313</div>
5314
5315<!-- _______________________________________________________________________ -->
5316<div class="doc_subsubsection">
5317 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5318</div>
5319
5320<div class="doc_text">
5321
5322<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5323<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]5324floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5325types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5326<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5327 declare float @llvm.powi.f32(float %Val, i32 %power)
5328 declare double @llvm.powi.f64(double %Val, i32 %power)
5329 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5330 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5331 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5332</pre>
5333
5334<h5>Overview:</h5>
5335
5336<p>
5337The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5338specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5339multiplications is not defined. When a vector of floating point type is
5340used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5341</p>
5342
5343<h5>Arguments:</h5>
5344
5345<p>
5346The second argument is an integer power, and the first is a value to raise to
5347that power.
5348</p>
5349
5350<h5>Semantics:</h5>
5351
5352<p>
5353This function returns the first value raised to the second power with an
5354unspecified sequence of rounding operations.</p>
5355</div>
5356
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5357<!-- _______________________________________________________________________ -->
5358<div class="doc_subsubsection">
5359 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5360</div>
5361
5362<div class="doc_text">
5363
5364<h5>Syntax:</h5>
5365<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5366floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5367types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5368<pre>
5369 declare float @llvm.sin.f32(float %Val)
5370 declare double @llvm.sin.f64(double %Val)
5371 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5372 declare fp128 @llvm.sin.f128(fp128 %Val)
5373 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5374</pre>
5375
5376<h5>Overview:</h5>
5377
5378<p>
5379The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5380</p>
5381
5382<h5>Arguments:</h5>
5383
5384<p>
5385The argument and return value are floating point numbers of the same type.
5386</p>
5387
5388<h5>Semantics:</h5>
5389
5390<p>
5391This function returns the sine of the specified operand, returning the
5392same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5393conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5394</div>
5395
5396<!-- _______________________________________________________________________ -->
5397<div class="doc_subsubsection">
5398 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5399</div>
5400
5401<div class="doc_text">
5402
5403<h5>Syntax:</h5>
5404<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5405floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5406types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5407<pre>
5408 declare float @llvm.cos.f32(float %Val)
5409 declare double @llvm.cos.f64(double %Val)
5410 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5411 declare fp128 @llvm.cos.f128(fp128 %Val)
5412 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5413</pre>
5414
5415<h5>Overview:</h5>
5416
5417<p>
5418The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5419</p>
5420
5421<h5>Arguments:</h5>
5422
5423<p>
5424The argument and return value are floating point numbers of the same type.
5425</p>
5426
5427<h5>Semantics:</h5>
5428
5429<p>
5430This function returns the cosine of the specified operand, returning the
5431same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5432conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5433</div>
5434
5435<!-- _______________________________________________________________________ -->
5436<div class="doc_subsubsection">
5437 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5438</div>
5439
5440<div class="doc_text">
5441
5442<h5>Syntax:</h5>
5443<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5444floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5445types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5446<pre>
5447 declare float @llvm.pow.f32(float %Val, float %Power)
5448 declare double @llvm.pow.f64(double %Val, double %Power)
5449 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5450 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5451 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5452</pre>
5453
5454<h5>Overview:</h5>
5455
5456<p>
5457The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5458specified (positive or negative) power.
5459</p>
5460
5461<h5>Arguments:</h5>
5462
5463<p>
5464The second argument is a floating point power, and the first is a value to
5465raise to that power.
5466</p>
5467
5468<h5>Semantics:</h5>
5469
5470<p>
5471This function returns the first value raised to the second power,
5472returning the
5473same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5474conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5475</div>
5476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5477
5478<!-- ======================================================================= -->
5479<div class="doc_subsection">
5480 <a name="int_manip">Bit Manipulation Intrinsics</a>
5481</div>
5482
5483<div class="doc_text">
5484<p>
5485LLVM provides intrinsics for a few important bit manipulation operations.
5486These allow efficient code generation for some algorithms.
5487</p>
5488
5489</div>
5490
5491<!-- _______________________________________________________________________ -->
5492<div class="doc_subsubsection">
5493 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5494</div>
5495
5496<div class="doc_text">
5497
5498<h5>Syntax:</h5>
5499<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5500type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5501<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5502 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5503 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5504 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5505</pre>
5506
5507<h5>Overview:</h5>
5508
5509<p>
5510The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5511values with an even number of bytes (positive multiple of 16 bits). These are
5512useful for performing operations on data that is not in the target's native
5513byte order.
5514</p>
5515
5516<h5>Semantics:</h5>
5517
5518<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5519The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5520and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5521intrinsic returns an i32 value that has the four bytes of the input i32
5522swapped, 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]5523i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5524<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5525additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5526</p>
5527
5528</div>
5529
5530<!-- _______________________________________________________________________ -->
5531<div class="doc_subsubsection">
5532 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5533</div>
5534
5535<div class="doc_text">
5536
5537<h5>Syntax:</h5>
5538<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5539width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5540<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5541 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5542 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5543 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5544 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5545 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5546</pre>
5547
5548<h5>Overview:</h5>
5549
5550<p>
5551The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5552value.
5553</p>
5554
5555<h5>Arguments:</h5>
5556
5557<p>
5558The only argument is the value to be counted. The argument may be of any
5559integer type. The return type must match the argument type.
5560</p>
5561
5562<h5>Semantics:</h5>
5563
5564<p>
5565The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5566</p>
5567</div>
5568
5569<!-- _______________________________________________________________________ -->
5570<div class="doc_subsubsection">
5571 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5572</div>
5573
5574<div class="doc_text">
5575
5576<h5>Syntax:</h5>
5577<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5578integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5580 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5581 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5582 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5583 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5584 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5585</pre>
5586
5587<h5>Overview:</h5>
5588
5589<p>
5590The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5591leading zeros in a variable.
5592</p>
5593
5594<h5>Arguments:</h5>
5595
5596<p>
5597The only argument is the value to be counted. The argument may be of any
5598integer type. The return type must match the argument type.
5599</p>
5600
5601<h5>Semantics:</h5>
5602
5603<p>
5604The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5605in a variable. If the src == 0 then the result is the size in bits of the type
5606of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5607</p>
5608</div>
5609
5610
5611
5612<!-- _______________________________________________________________________ -->
5613<div class="doc_subsubsection">
5614 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5615</div>
5616
5617<div class="doc_text">
5618
5619<h5>Syntax:</h5>
5620<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]5621integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5623 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5624 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5625 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5626 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5627 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5628</pre>
5629
5630<h5>Overview:</h5>
5631
5632<p>
5633The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5634trailing zeros.
5635</p>
5636
5637<h5>Arguments:</h5>
5638
5639<p>
5640The only argument is the value to be counted. The argument may be of any
5641integer type. The return type must match the argument type.
5642</p>
5643
5644<h5>Semantics:</h5>
5645
5646<p>
5647The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5648in a variable. If the src == 0 then the result is the size in bits of the type
5649of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5650</p>
5651</div>
5652
5653<!-- _______________________________________________________________________ -->
5654<div class="doc_subsubsection">
5655 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5656</div>
5657
5658<div class="doc_text">
5659
5660<h5>Syntax:</h5>
5661<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5662on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5663<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5664 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5665 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5666</pre>
5667
5668<h5>Overview:</h5>
5669<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5670range of bits from an integer value and returns them in the same bit width as
5671the original value.</p>
5672
5673<h5>Arguments:</h5>
5674<p>The first argument, <tt>%val</tt> and the result may be integer types of
5675any bit width but they must have the same bit width. The second and third
5676arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5677
5678<h5>Semantics:</h5>
5679<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5680of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5681<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5682operates in forward mode.</p>
5683<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5684right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5685only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5686<ol>
5687 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5688 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5689 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5690 to determine the number of bits to retain.</li>
5691 <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]5692 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5693</ol>
5694<p>In reverse mode, a similar computation is made except that the bits are
5695returned in the reverse order. So, for example, if <tt>X</tt> has the value
5696<tt>i16 0x0ACF (101011001111)</tt> and we apply
5697<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5698<tt>i16 0x0026 (000000100110)</tt>.</p>
5699</div>
5700
5701<div class="doc_subsubsection">
5702 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5703</div>
5704
5705<div class="doc_text">
5706
5707<h5>Syntax:</h5>
5708<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5709on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5710<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5711 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5712 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]5713</pre>
5714
5715<h5>Overview:</h5>
5716<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5717of bits in an integer value with another integer value. It returns the integer
5718with the replaced bits.</p>
5719
5720<h5>Arguments:</h5>
5721<p>The first argument, <tt>%val</tt> and the result may be integer types of
5722any bit width but they must have the same bit width. <tt>%val</tt> is the value
5723whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5724integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5725type since they specify only a bit index.</p>
5726
5727<h5>Semantics:</h5>
5728<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5729of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5730<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5731operates in forward mode.</p>
5732<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5733truncating it down to the size of the replacement area or zero extending it
5734up to that size.</p>
5735<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5736are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5737in <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]5738to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5739<p>In reverse mode, a similar computation is made except that the bits are
5740reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5741<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5742<h5>Examples:</h5>
5743<pre>
5744 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5745 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5746 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5747 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5748 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5749</pre>
5750</div>
5751
5752<!-- ======================================================================= -->
5753<div class="doc_subsection">
5754 <a name="int_debugger">Debugger Intrinsics</a>
5755</div>
5756
5757<div class="doc_text">
5758<p>
5759The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5760are described in the <a
5761href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5762Debugging</a> document.
5763</p>
5764</div>
5765
5766
5767<!-- ======================================================================= -->
5768<div class="doc_subsection">
5769 <a name="int_eh">Exception Handling Intrinsics</a>
5770</div>
5771
5772<div class="doc_text">
5773<p> The LLVM exception handling intrinsics (which all start with
5774<tt>llvm.eh.</tt> prefix), are described in the <a
5775href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5776Handling</a> document. </p>
5777</div>
5778
5779<!-- ======================================================================= -->
5780<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5781 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5782</div>
5783
5784<div class="doc_text">
5785<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5786 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5787 the <tt>nest</tt> attribute, from a function. The result is a callable
5788 function pointer lacking the nest parameter - the caller does not need
5789 to provide a value for it. Instead, the value to use is stored in
5790 advance in a "trampoline", a block of memory usually allocated
5791 on the stack, which also contains code to splice the nest value into the
5792 argument list. This is used to implement the GCC nested function address
5793 extension.
5794</p>
5795<p>
5796 For example, if the function is
5797 <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]5798 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]5799<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5800 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5801 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5802 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5803 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5804</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5805 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5806 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5807</div>
5808
5809<!-- _______________________________________________________________________ -->
5810<div class="doc_subsubsection">
5811 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5812</div>
5813<div class="doc_text">
5814<h5>Syntax:</h5>
5815<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5816declare 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]5817</pre>
5818<h5>Overview:</h5>
5819<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5820 This fills the memory pointed to by <tt>tramp</tt> with code
5821 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5822</p>
5823<h5>Arguments:</h5>
5824<p>
5825 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5826 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5827 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5828 intrinsic. Note that the size and the alignment are target-specific - LLVM
5829 currently provides no portable way of determining them, so a front-end that
5830 generates this intrinsic needs to have some target-specific knowledge.
5831 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]5832</p>
5833<h5>Semantics:</h5>
5834<p>
5835 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5836 dependent code, turning it into a function. A pointer to this function is
5837 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5838 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5839 before being called. The new function's signature is the same as that of
5840 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5841 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5842 of pointer type. Calling the new function is equivalent to calling
5843 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5844 missing <tt>nest</tt> argument. If, after calling
5845 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5846 modified, then the effect of any later call to the returned function pointer is
5847 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5848</p>
5849</div>
5850
5851<!-- ======================================================================= -->
5852<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5853 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5854</div>
5855
5856<div class="doc_text">
5857<p>
5858 These intrinsic functions expand the "universal IR" of LLVM to represent
5859 hardware constructs for atomic operations and memory synchronization. This
5860 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5861 is aimed at a low enough level to allow any programming models or APIs
5862 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5863 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5864 hardware behavior. Just as hardware provides a "universal IR" for source
5865 languages, it also provides a starting point for developing a "universal"
5866 atomic operation and synchronization IR.
5867</p>
5868<p>
5869 These do <em>not</em> form an API such as high-level threading libraries,
5870 software transaction memory systems, atomic primitives, and intrinsic
5871 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5872 application libraries. The hardware interface provided by LLVM should allow
5873 a clean implementation of all of these APIs and parallel programming models.
5874 No one model or paradigm should be selected above others unless the hardware
5875 itself ubiquitously does so.
5876
5877</p>
5878</div>
5879
5880<!-- _______________________________________________________________________ -->
5881<div class="doc_subsubsection">
5882 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5883</div>
5884<div class="doc_text">
5885<h5>Syntax:</h5>
5886<pre>
5887declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5888i1 &lt;device&gt; )
5889
5890</pre>
5891<h5>Overview:</h5>
5892<p>
5893 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5894 specific pairs of memory access types.
5895</p>
5896<h5>Arguments:</h5>
5897<p>
5898 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5899 The first four arguments enables a specific barrier as listed below. The fith
5900 argument specifies that the barrier applies to io or device or uncached memory.
5901
5902</p>
5903 <ul>
5904 <li><tt>ll</tt>: load-load barrier</li>
5905 <li><tt>ls</tt>: load-store barrier</li>
5906 <li><tt>sl</tt>: store-load barrier</li>
5907 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5908 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5909 </ul>
5910<h5>Semantics:</h5>
5911<p>
5912 This intrinsic causes the system to enforce some ordering constraints upon
5913 the loads and stores of the program. This barrier does not indicate
5914 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5915 which they occur. For any of the specified pairs of load and store operations
5916 (f.ex. load-load, or store-load), all of the first operations preceding the
5917 barrier will complete before any of the second operations succeeding the
5918 barrier begin. Specifically the semantics for each pairing is as follows:
5919</p>
5920 <ul>
5921 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5922 after the barrier begins.</li>
5923
5924 <li><tt>ls</tt>: All loads before the barrier must complete before any
5925 store after the barrier begins.</li>
5926 <li><tt>ss</tt>: All stores before the barrier must complete before any
5927 store after the barrier begins.</li>
5928 <li><tt>sl</tt>: All stores before the barrier must complete before any
5929 load after the barrier begins.</li>
5930 </ul>
5931<p>
5932 These semantics are applied with a logical "and" behavior when more than one
5933 is enabled in a single memory barrier intrinsic.
5934</p>
5935<p>
5936 Backends may implement stronger barriers than those requested when they do not
5937 support as fine grained a barrier as requested. Some architectures do not
5938 need all types of barriers and on such architectures, these become noops.
5939</p>
5940<h5>Example:</h5>
5941<pre>
5942%ptr = malloc i32
5943 store i32 4, %ptr
5944
5945%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5946 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5947 <i>; guarantee the above finishes</i>
5948 store i32 8, %ptr <i>; before this begins</i>
5949</pre>
5950</div>
5951
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5952<!-- _______________________________________________________________________ -->
5953<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5954 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5955</div>
5956<div class="doc_text">
5957<h5>Syntax:</h5>
5958<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5959 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5960 any integer bit width and for different address spaces. Not all targets
5961 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5962
5963<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5964declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5965declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5966declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5967declare 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]5968
5969</pre>
5970<h5>Overview:</h5>
5971<p>
5972 This loads a value in memory and compares it to a given value. If they are
5973 equal, it stores a new value into the memory.
5974</p>
5975<h5>Arguments:</h5>
5976<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5977 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5978 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5979 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5980 this integer type. While any bit width integer may be used, targets may only
5981 lower representations they support in hardware.
5982
5983</p>
5984<h5>Semantics:</h5>
5985<p>
5986 This entire intrinsic must be executed atomically. It first loads the value
5987 in memory pointed to by <tt>ptr</tt> and compares it with the value
5988 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5989 loaded value is yielded in all cases. This provides the equivalent of an
5990 atomic compare-and-swap operation within the SSA framework.
5991</p>
5992<h5>Examples:</h5>
5993
5994<pre>
5995%ptr = malloc i32
5996 store i32 4, %ptr
5997
5998%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5999%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6000 <i>; yields {i32}:result1 = 4</i>
6001%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6002%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6003
6004%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6005%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6006 <i>; yields {i32}:result2 = 8</i>
6007%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6008
6009%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6010</pre>
6011</div>
6012
6013<!-- _______________________________________________________________________ -->
6014<div class="doc_subsubsection">
6015 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6016</div>
6017<div class="doc_text">
6018<h5>Syntax:</h5>
6019
6020<p>
6021 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6022 integer bit width. Not all targets support all bit widths however.</p>
6023<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6024declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6025declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6026declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6027declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6028
6029</pre>
6030<h5>Overview:</h5>
6031<p>
6032 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6033 the value from memory. It then stores the value in <tt>val</tt> in the memory
6034 at <tt>ptr</tt>.
6035</p>
6036<h5>Arguments:</h5>
6037
6038<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6039 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6040 <tt>val</tt> argument and the result must be integers of the same bit width.
6041 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6042 integer type. The targets may only lower integer representations they
6043 support.
6044</p>
6045<h5>Semantics:</h5>
6046<p>
6047 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6048 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6049 equivalent of an atomic swap operation within the SSA framework.
6050
6051</p>
6052<h5>Examples:</h5>
6053<pre>
6054%ptr = malloc i32
6055 store i32 4, %ptr
6056
6057%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6058%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6059 <i>; yields {i32}:result1 = 4</i>
6060%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6061%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6062
6063%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6064%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6065 <i>; yields {i32}:result2 = 8</i>
6066
6067%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6068%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6069</pre>
6070</div>
6071
6072<!-- _______________________________________________________________________ -->
6073<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6074 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6075
6076</div>
6077<div class="doc_text">
6078<h5>Syntax:</h5>
6079<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6080 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]6081 integer bit width. Not all targets support all bit widths however.</p>
6082<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6083declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6084declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6085declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6086declare 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]6087
6088</pre>
6089<h5>Overview:</h5>
6090<p>
6091 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6092 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6093</p>
6094<h5>Arguments:</h5>
6095<p>
6096
6097 The intrinsic takes two arguments, the first a pointer to an integer value
6098 and the second an integer value. The result is also an integer value. These
6099 integer types can have any bit width, but they must all have the same bit
6100 width. The targets may only lower integer representations they support.
6101</p>
6102<h5>Semantics:</h5>
6103<p>
6104 This intrinsic does a series of operations atomically. It first loads the
6105 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6106 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6107</p>
6108
6109<h5>Examples:</h5>
6110<pre>
6111%ptr = malloc i32
6112 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6113%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6114 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6115%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6116 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6117%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6118 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6119%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6120</pre>
6121</div>
6122
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6123<!-- _______________________________________________________________________ -->
6124<div class="doc_subsubsection">
6125 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6126
6127</div>
6128<div class="doc_text">
6129<h5>Syntax:</h5>
6130<p>
6131 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]6132 any integer bit width and for different address spaces. Not all targets
6133 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6134<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6135declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6136declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6137declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6138declare 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]6139
6140</pre>
6141<h5>Overview:</h5>
6142<p>
6143 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6144 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6145</p>
6146<h5>Arguments:</h5>
6147<p>
6148
6149 The intrinsic takes two arguments, the first a pointer to an integer value
6150 and the second an integer value. The result is also an integer value. These
6151 integer types can have any bit width, but they must all have the same bit
6152 width. The targets may only lower integer representations they support.
6153</p>
6154<h5>Semantics:</h5>
6155<p>
6156 This intrinsic does a series of operations atomically. It first loads the
6157 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6158 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6159</p>
6160
6161<h5>Examples:</h5>
6162<pre>
6163%ptr = malloc i32
6164 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6165%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6166 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6167%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6168 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6169%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6170 <i>; yields {i32}:result3 = 2</i>
6171%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6172</pre>
6173</div>
6174
6175<!-- _______________________________________________________________________ -->
6176<div class="doc_subsubsection">
6177 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6178 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6179 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6180 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6181
6182</div>
6183<div class="doc_text">
6184<h5>Syntax:</h5>
6185<p>
6186 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6187 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6188 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6189 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6190<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6191declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6192declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6193declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6194declare 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]6195
6196</pre>
6197
6198<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6199declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6200declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6201declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6202declare 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]6203
6204</pre>
6205
6206<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6207declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6208declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6209declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6210declare 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]6211
6212</pre>
6213
6214<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6215declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6216declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6217declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6218declare 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]6219
6220</pre>
6221<h5>Overview:</h5>
6222<p>
6223 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6224 the value stored in memory at <tt>ptr</tt>. It yields the original value
6225 at <tt>ptr</tt>.
6226</p>
6227<h5>Arguments:</h5>
6228<p>
6229
6230 These intrinsics take two arguments, the first a pointer to an integer value
6231 and the second an integer value. The result is also an integer value. These
6232 integer types can have any bit width, but they must all have the same bit
6233 width. The targets may only lower integer representations they support.
6234</p>
6235<h5>Semantics:</h5>
6236<p>
6237 These intrinsics does a series of operations atomically. They first load the
6238 value stored at <tt>ptr</tt>. They then do the bitwise operation
6239 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6240 value stored at <tt>ptr</tt>.
6241</p>
6242
6243<h5>Examples:</h5>
6244<pre>
6245%ptr = malloc i32
6246 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6247%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6248 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6249%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6250 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6251%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6252 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6253%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6254 <i>; yields {i32}:result3 = FF</i>
6255%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6256</pre>
6257</div>
6258
6259
6260<!-- _______________________________________________________________________ -->
6261<div class="doc_subsubsection">
6262 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6263 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6264 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6265 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6266
6267</div>
6268<div class="doc_text">
6269<h5>Syntax:</h5>
6270<p>
6271 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6272 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6273 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6274 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6275 support all bit widths however.</p>
6276<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6277declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6278declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6279declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6280declare 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]6281
6282</pre>
6283
6284<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6285declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6286declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6287declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6288declare 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]6289
6290</pre>
6291
6292<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6293declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6294declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6295declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6296declare 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]6297
6298</pre>
6299
6300<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6301declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6302declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6303declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6304declare 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]6305
6306</pre>
6307<h5>Overview:</h5>
6308<p>
6309 These intrinsics takes the signed or unsigned minimum or maximum of
6310 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6311 original value at <tt>ptr</tt>.
6312</p>
6313<h5>Arguments:</h5>
6314<p>
6315
6316 These intrinsics take two arguments, the first a pointer to an integer value
6317 and the second an integer value. The result is also an integer value. These
6318 integer types can have any bit width, but they must all have the same bit
6319 width. The targets may only lower integer representations they support.
6320</p>
6321<h5>Semantics:</h5>
6322<p>
6323 These intrinsics does a series of operations atomically. They first load the
6324 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6325 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6326 the original value stored at <tt>ptr</tt>.
6327</p>
6328
6329<h5>Examples:</h5>
6330<pre>
6331%ptr = malloc i32
6332 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6333%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6334 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6335%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6336 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6337%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6338 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6339%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6340 <i>; yields {i32}:result3 = 8</i>
6341%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6342</pre>
6343</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6344
6345<!-- ======================================================================= -->
6346<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6347 <a name="int_general">General Intrinsics</a>
6348</div>
6349
6350<div class="doc_text">
6351<p> This class of intrinsics is designed to be generic and has
6352no specific purpose. </p>
6353</div>
6354
6355<!-- _______________________________________________________________________ -->
6356<div class="doc_subsubsection">
6357 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6358</div>
6359
6360<div class="doc_text">
6361
6362<h5>Syntax:</h5>
6363<pre>
6364 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6365</pre>
6366
6367<h5>Overview:</h5>
6368
6369<p>
6370The '<tt>llvm.var.annotation</tt>' intrinsic
6371</p>
6372
6373<h5>Arguments:</h5>
6374
6375<p>
6376The first argument is a pointer to a value, the second is a pointer to a
6377global string, the third is a pointer to a global string which is the source
6378file name, and the last argument is the line number.
6379</p>
6380
6381<h5>Semantics:</h5>
6382
6383<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6384This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6385This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6386annotations. These have no other defined use, they are ignored by code
6387generation and optimization.
6388</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6389</div>
6390
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6391<!-- _______________________________________________________________________ -->
6392<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6393 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6394</div>
6395
6396<div class="doc_text">
6397
6398<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6399<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6400any integer bit width.
6401</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6402<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6403 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6404 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6405 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6406 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6407 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]6408</pre>
6409
6410<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6411
6412<p>
6413The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6414</p>
6415
6416<h5>Arguments:</h5>
6417
6418<p>
6419The first argument is an integer value (result of some expression),
6420the second is a pointer to a global string, the third is a pointer to a global
6421string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6422It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6423</p>
6424
6425<h5>Semantics:</h5>
6426
6427<p>
6428This intrinsic allows annotations to be put on arbitrary expressions
6429with arbitrary strings. This can be useful for special purpose optimizations
6430that want to look for these annotations. These have no other defined use, they
6431are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6432</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6433</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6434
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6435<!-- _______________________________________________________________________ -->
6436<div class="doc_subsubsection">
6437 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6438</div>
6439
6440<div class="doc_text">
6441
6442<h5>Syntax:</h5>
6443<pre>
6444 declare void @llvm.trap()
6445</pre>
6446
6447<h5>Overview:</h5>
6448
6449<p>
6450The '<tt>llvm.trap</tt>' intrinsic
6451</p>
6452
6453<h5>Arguments:</h5>
6454
6455<p>
6456None
6457</p>
6458
6459<h5>Semantics:</h5>
6460
6461<p>
6462This intrinsics is lowered to the target dependent trap instruction. If the
6463target does not have a trap instruction, this intrinsic will be lowered to the
6464call of the abort() function.
6465</p>
6466</div>
6467
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6468<!-- _______________________________________________________________________ -->
6469<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6470 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6471</div>
6472<div class="doc_text">
6473<h5>Syntax:</h5>
6474<pre>
6475declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6476
6477</pre>
6478<h5>Overview:</h5>
6479<p>
6480 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6481 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6482 it is placed on the stack before local variables.
6483</p>
6484<h5>Arguments:</h5>
6485<p>
6486 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6487 first argument is the value loaded from the stack guard
6488 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6489 has enough space to hold the value of the guard.
6490</p>
6491<h5>Semantics:</h5>
6492<p>
6493 This intrinsic causes the prologue/epilogue inserter to force the position of
6494 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6495 stack. This is to ensure that if a local variable on the stack is overwritten,
6496 it will destroy the value of the guard. When the function exits, the guard on
6497 the stack is checked against the original guard. If they're different, then
6498 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6499</p>
6500</div>
6501
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6502<!-- *********************************************************************** -->
6503<hr>
6504<address>
6505 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6506 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6507 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame]6508 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]6509
6510 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6511 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6512 Last modified: $Date$
6513</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6514
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6515</body>
6516</html>