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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>
444 <i>; Convert [13x i8 ]* to i8 *...</i>
445 %cast210 = <a
446 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
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
568<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
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>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]736@G = constant float 1.0 addrspace(5), 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
897 caller.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]898
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]899 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]900 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]901 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
902 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]903 </dl>
904
905</div>
906
907<!-- ======================================================================= -->
908<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]909 <a name="gc">Garbage Collector Names</a>
910</div>
911
912<div class="doc_text">
913<p>Each function may specify a garbage collector name, which is simply a
914string.</p>
915
916<div class="doc_code"><pre
917>define void @f() gc "name" { ...</pre></div>
918
919<p>The compiler declares the supported values of <i>name</i>. Specifying a
920collector which will cause the compiler to alter its output in order to support
921the named garbage collection algorithm.</p>
922</div>
923
924<!-- ======================================================================= -->
925<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]926 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]927</div>
928
929<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]930
931<p>Function attributes are set to communicate additional information about
932 a function. Function attributes are considered to be part of the function,
933 not of the function type, so functions with different parameter attributes
934 can have the same function type.</p>
935
936 <p>Function attributes are simple keywords that follow the type specified. If
937 multiple attributes are needed, they are space separated. For
938 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]939
940<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]941<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]942define void @f() noinline { ... }
943define void @f() alwaysinline { ... }
944define void @f() alwaysinline optsize { ... }
945define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]946</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]947</div>
948
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]949<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]950<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]951<dd>This attribute indicates that the inliner should attempt to inline this
952function into callers whenever possible, ignoring any active inlining size
953threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]954
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]955<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]956<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]957in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]958<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]959
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]960<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]961<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]962make choices that keep the code size of this function low, and otherwise do
963optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]964
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]965<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]966<dd>This function attribute indicates that the function never returns normally.
967This produces undefined behavior at runtime if the function ever does
968dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]969
970<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]971<dd>This function attribute indicates that the function never returns with an
972unwind or exceptional control flow. If the function does unwind, its runtime
973behavior is undefined.</dd>
974
975<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]976<dd>This attribute indicates that the function computes its result (or the
977exception it throws) based strictly on its arguments, without dereferencing any
978pointer arguments or otherwise accessing any mutable state (e.g. memory, control
979registers, etc) visible to caller functions. It does not write through any
980pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
981never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]982
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]983<dt><tt><a name="readonly">readonly</a></tt></dt>
984<dd>This attribute indicates that the function does not write through any
985pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
986or otherwise modify any state (e.g. memory, control registers, etc) visible to
987caller functions. It may dereference pointer arguments and read state that may
988be set in the caller. A readonly function always returns the same value (or
989throws the same exception) when called with the same set of arguments and global
990state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]991
992<dt><tt><a name="ssp">ssp</a></tt></dt>
993<dd>This attribute indicates that the function should emit a stack smashing
994protector. It is in the form of a "canary"&mdash;a random value placed on the
995stack before the local variables that's checked upon return from the function to
996see if it has been overwritten. A heuristic is used to determine if a function
997needs stack protectors or not.</dd>
998
999<dt><tt>ssp-req</tt></dt>
1000<dd>This attribute indicates that the function should <em>always</em> emit a
1001stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
1002function attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1003</dl>
1004
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1005</div>
1006
1007<!-- ======================================================================= -->
1008<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1009 <a name="moduleasm">Module-Level Inline Assembly</a>
1010</div>
1011
1012<div class="doc_text">
1013<p>
1014Modules may contain "module-level inline asm" blocks, which corresponds to the
1015GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1016LLVM and treated as a single unit, but may be separated in the .ll file if
1017desired. The syntax is very simple:
1018</p>
1019
1020<div class="doc_code">
1021<pre>
1022module asm "inline asm code goes here"
1023module asm "more can go here"
1024</pre>
1025</div>
1026
1027<p>The strings can contain any character by escaping non-printable characters.
1028 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1029 for the number.
1030</p>
1031
1032<p>
1033 The inline asm code is simply printed to the machine code .s file when
1034 assembly code is generated.
1035</p>
1036</div>
1037
1038<!-- ======================================================================= -->
1039<div class="doc_subsection">
1040 <a name="datalayout">Data Layout</a>
1041</div>
1042
1043<div class="doc_text">
1044<p>A module may specify a target specific data layout string that specifies how
1045data is to be laid out in memory. The syntax for the data layout is simply:</p>
1046<pre> target datalayout = "<i>layout specification</i>"</pre>
1047<p>The <i>layout specification</i> consists of a list of specifications
1048separated by the minus sign character ('-'). Each specification starts with a
1049letter and may include other information after the letter to define some
1050aspect of the data layout. The specifications accepted are as follows: </p>
1051<dl>
1052 <dt><tt>E</tt></dt>
1053 <dd>Specifies that the target lays out data in big-endian form. That is, the
1054 bits with the most significance have the lowest address location.</dd>
1055 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1056 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1057 the bits with the least significance have the lowest address location.</dd>
1058 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1059 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1060 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1061 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1062 too.</dd>
1063 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1064 <dd>This specifies the alignment for an integer type of a given bit
1065 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1066 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1067 <dd>This specifies the alignment for a vector type of a given bit
1068 <i>size</i>.</dd>
1069 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1070 <dd>This specifies the alignment for a floating point type of a given bit
1071 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1072 (double).</dd>
1073 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1074 <dd>This specifies the alignment for an aggregate type of a given bit
1075 <i>size</i>.</dd>
1076</dl>
1077<p>When constructing the data layout for a given target, LLVM starts with a
1078default set of specifications which are then (possibly) overriden by the
1079specifications in the <tt>datalayout</tt> keyword. The default specifications
1080are given in this list:</p>
1081<ul>
1082 <li><tt>E</tt> - big endian</li>
1083 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1084 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1085 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1086 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1087 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1088 <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]1089 alignment of 64-bits</li>
1090 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1091 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1092 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1093 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1094 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1095</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1096<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1097following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1098<ol>
1099 <li>If the type sought is an exact match for one of the specifications, that
1100 specification is used.</li>
1101 <li>If no match is found, and the type sought is an integer type, then the
1102 smallest integer type that is larger than the bitwidth of the sought type is
1103 used. If none of the specifications are larger than the bitwidth then the the
1104 largest integer type is used. For example, given the default specifications
1105 above, the i7 type will use the alignment of i8 (next largest) while both
1106 i65 and i256 will use the alignment of i64 (largest specified).</li>
1107 <li>If no match is found, and the type sought is a vector type, then the
1108 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1109 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1110 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1111</ol>
1112</div>
1113
1114<!-- *********************************************************************** -->
1115<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1116<!-- *********************************************************************** -->
1117
1118<div class="doc_text">
1119
1120<p>The LLVM type system is one of the most important features of the
1121intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1122optimizations to be performed on the intermediate representation directly,
1123without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1124extra analyses on the side before the transformation. A strong type
1125system makes it easier to read the generated code and enables novel
1126analyses and transformations that are not feasible to perform on normal
1127three address code representations.</p>
1128
1129</div>
1130
1131<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1132<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1133Classifications</a> </div>
1134<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1135<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1136classifications:</p>
1137
1138<table border="1" cellspacing="0" cellpadding="4">
1139 <tbody>
1140 <tr><th>Classification</th><th>Types</th></tr>
1141 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1142 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1143 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1144 </tr>
1145 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1146 <td><a href="#t_floating">floating point</a></td>
1147 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1148 </tr>
1149 <tr>
1150 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1151 <td><a href="#t_integer">integer</a>,
1152 <a href="#t_floating">floating point</a>,
1153 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1154 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1155 <a href="#t_struct">structure</a>,
1156 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1157 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1158 </td>
1159 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1160 <tr>
1161 <td><a href="#t_primitive">primitive</a></td>
1162 <td><a href="#t_label">label</a>,
1163 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1164 <a href="#t_floating">floating point</a>.</td>
1165 </tr>
1166 <tr>
1167 <td><a href="#t_derived">derived</a></td>
1168 <td><a href="#t_integer">integer</a>,
1169 <a href="#t_array">array</a>,
1170 <a href="#t_function">function</a>,
1171 <a href="#t_pointer">pointer</a>,
1172 <a href="#t_struct">structure</a>,
1173 <a href="#t_pstruct">packed structure</a>,
1174 <a href="#t_vector">vector</a>,
1175 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1176 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1177 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1178 </tbody>
1179</table>
1180
1181<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1182most important. Values of these types are the only ones which can be
1183produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1184instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1185</div>
1186
1187<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1188<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1189
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1190<div class="doc_text">
1191<p>The primitive types are the fundamental building blocks of the LLVM
1192system.</p>
1193
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1194</div>
1195
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1196<!-- _______________________________________________________________________ -->
1197<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1198
1199<div class="doc_text">
1200 <table>
1201 <tbody>
1202 <tr><th>Type</th><th>Description</th></tr>
1203 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1204 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1205 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1206 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1207 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1208 </tbody>
1209 </table>
1210</div>
1211
1212<!-- _______________________________________________________________________ -->
1213<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1214
1215<div class="doc_text">
1216<h5>Overview:</h5>
1217<p>The void type does not represent any value and has no size.</p>
1218
1219<h5>Syntax:</h5>
1220
1221<pre>
1222 void
1223</pre>
1224</div>
1225
1226<!-- _______________________________________________________________________ -->
1227<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1228
1229<div class="doc_text">
1230<h5>Overview:</h5>
1231<p>The label type represents code labels.</p>
1232
1233<h5>Syntax:</h5>
1234
1235<pre>
1236 label
1237</pre>
1238</div>
1239
1240
1241<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1242<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1243
1244<div class="doc_text">
1245
1246<p>The real power in LLVM comes from the derived types in the system.
1247This is what allows a programmer to represent arrays, functions,
1248pointers, and other useful types. Note that these derived types may be
1249recursive: For example, it is possible to have a two dimensional array.</p>
1250
1251</div>
1252
1253<!-- _______________________________________________________________________ -->
1254<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1255
1256<div class="doc_text">
1257
1258<h5>Overview:</h5>
1259<p>The integer type is a very simple derived type that simply specifies an
1260arbitrary bit width for the integer type desired. Any bit width from 1 bit to
12612^23-1 (about 8 million) can be specified.</p>
1262
1263<h5>Syntax:</h5>
1264
1265<pre>
1266 iN
1267</pre>
1268
1269<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1270value.</p>
1271
1272<h5>Examples:</h5>
1273<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1274 <tbody>
1275 <tr>
1276 <td><tt>i1</tt></td>
1277 <td>a single-bit integer.</td>
1278 </tr><tr>
1279 <td><tt>i32</tt></td>
1280 <td>a 32-bit integer.</td>
1281 </tr><tr>
1282 <td><tt>i1942652</tt></td>
1283 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1284 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1285 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1286</table>
1287</div>
1288
1289<!-- _______________________________________________________________________ -->
1290<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1291
1292<div class="doc_text">
1293
1294<h5>Overview:</h5>
1295
1296<p>The array type is a very simple derived type that arranges elements
1297sequentially in memory. The array type requires a size (number of
1298elements) and an underlying data type.</p>
1299
1300<h5>Syntax:</h5>
1301
1302<pre>
1303 [&lt;# elements&gt; x &lt;elementtype&gt;]
1304</pre>
1305
1306<p>The number of elements is a constant integer value; elementtype may
1307be any type with a size.</p>
1308
1309<h5>Examples:</h5>
1310<table class="layout">
1311 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1312 <td class="left"><tt>[40 x i32]</tt></td>
1313 <td class="left">Array of 40 32-bit integer values.</td>
1314 </tr>
1315 <tr class="layout">
1316 <td class="left"><tt>[41 x i32]</tt></td>
1317 <td class="left">Array of 41 32-bit integer values.</td>
1318 </tr>
1319 <tr class="layout">
1320 <td class="left"><tt>[4 x i8]</tt></td>
1321 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1322 </tr>
1323</table>
1324<p>Here are some examples of multidimensional arrays:</p>
1325<table class="layout">
1326 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1327 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1328 <td class="left">3x4 array of 32-bit integer values.</td>
1329 </tr>
1330 <tr class="layout">
1331 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1332 <td class="left">12x10 array of single precision floating point values.</td>
1333 </tr>
1334 <tr class="layout">
1335 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1336 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1337 </tr>
1338</table>
1339
1340<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1341length array. Normally, accesses past the end of an array are undefined in
1342LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1343As a special case, however, zero length arrays are recognized to be variable
1344length. This allows implementation of 'pascal style arrays' with the LLVM
1345type "{ i32, [0 x float]}", for example.</p>
1346
1347</div>
1348
1349<!-- _______________________________________________________________________ -->
1350<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1351<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1352
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1353<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1354
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1355<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1356consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1357return 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]1358If 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]1359class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1360
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1361<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1362
1363<pre>
1364 &lt;returntype list&gt; (&lt;parameter list&gt;)
1365</pre>
1366
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1367<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1368specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1369which indicates that the function takes a variable number of arguments.
1370Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1371 href="#int_varargs">variable argument handling intrinsic</a> functions.
1372'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1373<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1375<h5>Examples:</h5>
1376<table class="layout">
1377 <tr class="layout">
1378 <td class="left"><tt>i32 (i32)</tt></td>
1379 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1380 </td>
1381 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1382 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1383 </tt></td>
1384 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1385 an <tt>i16</tt> that should be sign extended and a
1386 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1387 <tt>float</tt>.
1388 </td>
1389 </tr><tr class="layout">
1390 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1391 <td class="left">A vararg function that takes at least one
1392 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1393 which returns an integer. This is the signature for <tt>printf</tt> in
1394 LLVM.
1395 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1396 </tr><tr class="layout">
1397 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Devang Patel6dddba22008-03-24 18:10:52 +0000[diff] [blame]1398 <td class="left">A function taking an <tt>i32></tt>, returning two
1399 <tt> i32 </tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1400 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1401 </tr>
1402</table>
1403
1404</div>
1405<!-- _______________________________________________________________________ -->
1406<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1407<div class="doc_text">
1408<h5>Overview:</h5>
1409<p>The structure type is used to represent a collection of data members
1410together in memory. The packing of the field types is defined to match
1411the ABI of the underlying processor. The elements of a structure may
1412be any type that has a size.</p>
1413<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1414and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1415field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1416instruction.</p>
1417<h5>Syntax:</h5>
1418<pre> { &lt;type list&gt; }<br></pre>
1419<h5>Examples:</h5>
1420<table class="layout">
1421 <tr class="layout">
1422 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1423 <td class="left">A triple of three <tt>i32</tt> values</td>
1424 </tr><tr class="layout">
1425 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1426 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1427 second element is a <a href="#t_pointer">pointer</a> to a
1428 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1429 an <tt>i32</tt>.</td>
1430 </tr>
1431</table>
1432</div>
1433
1434<!-- _______________________________________________________________________ -->
1435<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1436</div>
1437<div class="doc_text">
1438<h5>Overview:</h5>
1439<p>The packed structure type is used to represent a collection of data members
1440together in memory. There is no padding between fields. Further, the alignment
1441of a packed structure is 1 byte. The elements of a packed structure may
1442be any type that has a size.</p>
1443<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1444and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1445field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1446instruction.</p>
1447<h5>Syntax:</h5>
1448<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1449<h5>Examples:</h5>
1450<table class="layout">
1451 <tr class="layout">
1452 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1453 <td class="left">A triple of three <tt>i32</tt> values</td>
1454 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1455 <td class="left">
1456<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1457 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1458 second element is a <a href="#t_pointer">pointer</a> to a
1459 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1460 an <tt>i32</tt>.</td>
1461 </tr>
1462</table>
1463</div>
1464
1465<!-- _______________________________________________________________________ -->
1466<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1467<div class="doc_text">
1468<h5>Overview:</h5>
1469<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1470reference to another object, which must live in memory. Pointer types may have
1471an optional address space attribute defining the target-specific numbered
1472address space where the pointed-to object resides. The default address space is
1473zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1474<h5>Syntax:</h5>
1475<pre> &lt;type&gt; *<br></pre>
1476<h5>Examples:</h5>
1477<table class="layout">
1478 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1479 <td class="left"><tt>[4x i32]*</tt></td>
1480 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1481 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1482 </tr>
1483 <tr class="layout">
1484 <td class="left"><tt>i32 (i32 *) *</tt></td>
1485 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1486 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1487 <tt>i32</tt>.</td>
1488 </tr>
1489 <tr class="layout">
1490 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1491 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1492 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1493 </tr>
1494</table>
1495</div>
1496
1497<!-- _______________________________________________________________________ -->
1498<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1499<div class="doc_text">
1500
1501<h5>Overview:</h5>
1502
1503<p>A vector type is a simple derived type that represents a vector
1504of elements. Vector types are used when multiple primitive data
1505are operated in parallel using a single instruction (SIMD).
1506A vector type requires a size (number of
1507elements) and an underlying primitive data type. Vectors must have a power
1508of two length (1, 2, 4, 8, 16 ...). Vector types are
1509considered <a href="#t_firstclass">first class</a>.</p>
1510
1511<h5>Syntax:</h5>
1512
1513<pre>
1514 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1515</pre>
1516
1517<p>The number of elements is a constant integer value; elementtype may
1518be any integer or floating point type.</p>
1519
1520<h5>Examples:</h5>
1521
1522<table class="layout">
1523 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1524 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1525 <td class="left">Vector of 4 32-bit integer values.</td>
1526 </tr>
1527 <tr class="layout">
1528 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1529 <td class="left">Vector of 8 32-bit floating-point values.</td>
1530 </tr>
1531 <tr class="layout">
1532 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1533 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1534 </tr>
1535</table>
1536</div>
1537
1538<!-- _______________________________________________________________________ -->
1539<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1540<div class="doc_text">
1541
1542<h5>Overview:</h5>
1543
1544<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1545corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1546In LLVM, opaque types can eventually be resolved to any type (not just a
1547structure type).</p>
1548
1549<h5>Syntax:</h5>
1550
1551<pre>
1552 opaque
1553</pre>
1554
1555<h5>Examples:</h5>
1556
1557<table class="layout">
1558 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1559 <td class="left"><tt>opaque</tt></td>
1560 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1561 </tr>
1562</table>
1563</div>
1564
1565
1566<!-- *********************************************************************** -->
1567<div class="doc_section"> <a name="constants">Constants</a> </div>
1568<!-- *********************************************************************** -->
1569
1570<div class="doc_text">
1571
1572<p>LLVM has several different basic types of constants. This section describes
1573them all and their syntax.</p>
1574
1575</div>
1576
1577<!-- ======================================================================= -->
1578<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1579
1580<div class="doc_text">
1581
1582<dl>
1583 <dt><b>Boolean constants</b></dt>
1584
1585 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1586 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1587 </dd>
1588
1589 <dt><b>Integer constants</b></dt>
1590
1591 <dd>Standard integers (such as '4') are constants of the <a
1592 href="#t_integer">integer</a> type. Negative numbers may be used with
1593 integer types.
1594 </dd>
1595
1596 <dt><b>Floating point constants</b></dt>
1597
1598 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1599 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1600 notation (see below). The assembler requires the exact decimal value of
1601 a floating-point constant. For example, the assembler accepts 1.25 but
1602 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1603 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1604
1605 <dt><b>Null pointer constants</b></dt>
1606
1607 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1608 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1609
1610</dl>
1611
1612<p>The one non-intuitive notation for constants is the optional hexadecimal form
1613of floating point constants. For example, the form '<tt>double
16140x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
16154.5e+15</tt>'. The only time hexadecimal floating point constants are required
1616(and the only time that they are generated by the disassembler) is when a
1617floating point constant must be emitted but it cannot be represented as a
1618decimal floating point number. For example, NaN's, infinities, and other
1619special values are represented in their IEEE hexadecimal format so that
1620assembly and disassembly do not cause any bits to change in the constants.</p>
1621
1622</div>
1623
1624<!-- ======================================================================= -->
1625<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1626</div>
1627
1628<div class="doc_text">
1629<p>Aggregate constants arise from aggregation of simple constants
1630and smaller aggregate constants.</p>
1631
1632<dl>
1633 <dt><b>Structure constants</b></dt>
1634
1635 <dd>Structure constants are represented with notation similar to structure
1636 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1637 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1638 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]1639 must have <a href="#t_struct">structure type</a>, and the number and
1640 types of elements must match those specified by the type.
1641 </dd>
1642
1643 <dt><b>Array constants</b></dt>
1644
1645 <dd>Array constants are represented with notation similar to array type
1646 definitions (a comma separated list of elements, surrounded by square brackets
1647 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1648 constants must have <a href="#t_array">array type</a>, and the number and
1649 types of elements must match those specified by the type.
1650 </dd>
1651
1652 <dt><b>Vector constants</b></dt>
1653
1654 <dd>Vector constants are represented with notation similar to vector type
1655 definitions (a comma separated list of elements, surrounded by
1656 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1657 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1658 href="#t_vector">vector type</a>, and the number and types of elements must
1659 match those specified by the type.
1660 </dd>
1661
1662 <dt><b>Zero initialization</b></dt>
1663
1664 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1665 value to zero of <em>any</em> type, including scalar and aggregate types.
1666 This is often used to avoid having to print large zero initializers (e.g. for
1667 large arrays) and is always exactly equivalent to using explicit zero
1668 initializers.
1669 </dd>
1670</dl>
1671
1672</div>
1673
1674<!-- ======================================================================= -->
1675<div class="doc_subsection">
1676 <a name="globalconstants">Global Variable and Function Addresses</a>
1677</div>
1678
1679<div class="doc_text">
1680
1681<p>The addresses of <a href="#globalvars">global variables</a> and <a
1682href="#functionstructure">functions</a> are always implicitly valid (link-time)
1683constants. These constants are explicitly referenced when the <a
1684href="#identifiers">identifier for the global</a> is used and always have <a
1685href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1686file:</p>
1687
1688<div class="doc_code">
1689<pre>
1690@X = global i32 17
1691@Y = global i32 42
1692@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1693</pre>
1694</div>
1695
1696</div>
1697
1698<!-- ======================================================================= -->
1699<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1700<div class="doc_text">
1701 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1702 no specific value. Undefined values may be of any type and be used anywhere
1703 a constant is permitted.</p>
1704
1705 <p>Undefined values indicate to the compiler that the program is well defined
1706 no matter what value is used, giving the compiler more freedom to optimize.
1707 </p>
1708</div>
1709
1710<!-- ======================================================================= -->
1711<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1712</div>
1713
1714<div class="doc_text">
1715
1716<p>Constant expressions are used to allow expressions involving other constants
1717to be used as constants. Constant expressions may be of any <a
1718href="#t_firstclass">first class</a> type and may involve any LLVM operation
1719that does not have side effects (e.g. load and call are not supported). The
1720following is the syntax for constant expressions:</p>
1721
1722<dl>
1723 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1724 <dd>Truncate a constant to another type. The bit size of CST must be larger
1725 than the bit size of TYPE. Both types must be integers.</dd>
1726
1727 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1728 <dd>Zero extend a constant to another type. The bit size of CST must be
1729 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1730
1731 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1732 <dd>Sign extend a constant to another type. The bit size of CST must be
1733 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1734
1735 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1736 <dd>Truncate a floating point constant to another floating point type. The
1737 size of CST must be larger than the size of TYPE. Both types must be
1738 floating point.</dd>
1739
1740 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1741 <dd>Floating point extend a constant to another type. The size of CST must be
1742 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1743
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1744 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1745 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1746 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1747 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1748 of the same number of elements. If the value won't fit in the integer type,
1749 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1750
1751 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1752 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1753 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1754 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1755 of the same number of elements. If the value won't fit in the integer type,
1756 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1757
1758 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1759 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1760 constant. TYPE must be a scalar or vector floating point type. CST must be of
1761 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1762 of the same number of elements. If the value won't fit in the floating point
1763 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1764
1765 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1766 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1767 constant. TYPE must be a scalar or vector floating point type. CST must be of
1768 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1769 of the same number of elements. If the value won't fit in the floating point
1770 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1771
1772 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1773 <dd>Convert a pointer typed constant to the corresponding integer constant
1774 TYPE must be an integer type. CST must be of pointer type. The CST value is
1775 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1776
1777 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1778 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1779 pointer type. CST must be of integer type. The CST value is zero extended,
1780 truncated, or unchanged to make it fit in a pointer size. This one is
1781 <i>really</i> dangerous!</dd>
1782
1783 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1784 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1785 identical (same number of bits). The conversion is done as if the CST value
1786 was stored to memory and read back as TYPE. In other words, no bits change
1787 with this operator, just the type. This can be used for conversion of
1788 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]1789 pointers it is only valid to cast to another pointer type. It is not valid
1790 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1791 </dd>
1792
1793 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1794
1795 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1796 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1797 instruction, the index list may have zero or more indexes, which are required
1798 to make sense for the type of "CSTPTR".</dd>
1799
1800 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1801
1802 <dd>Perform the <a href="#i_select">select operation</a> on
1803 constants.</dd>
1804
1805 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1806 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1807
1808 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1809 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1810
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1811 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1812 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1813
1814 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1815 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1816
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1817 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1818
1819 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1820 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1821
1822 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1823
1824 <dd>Perform the <a href="#i_insertelement">insertelement
1825 operation</a> on constants.</dd>
1826
1827
1828 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1829
1830 <dd>Perform the <a href="#i_shufflevector">shufflevector
1831 operation</a> on constants.</dd>
1832
1833 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1834
1835 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1836 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1837 binary</a> operations. The constraints on operands are the same as those for
1838 the corresponding instruction (e.g. no bitwise operations on floating point
1839 values are allowed).</dd>
1840</dl>
1841</div>
1842
1843<!-- *********************************************************************** -->
1844<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1845<!-- *********************************************************************** -->
1846
1847<!-- ======================================================================= -->
1848<div class="doc_subsection">
1849<a name="inlineasm">Inline Assembler Expressions</a>
1850</div>
1851
1852<div class="doc_text">
1853
1854<p>
1855LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1856Module-Level Inline Assembly</a>) through the use of a special value. This
1857value represents the inline assembler as a string (containing the instructions
1858to emit), a list of operand constraints (stored as a string), and a flag that
1859indicates whether or not the inline asm expression has side effects. An example
1860inline assembler expression is:
1861</p>
1862
1863<div class="doc_code">
1864<pre>
1865i32 (i32) asm "bswap $0", "=r,r"
1866</pre>
1867</div>
1868
1869<p>
1870Inline assembler expressions may <b>only</b> be used as the callee operand of
1871a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1872</p>
1873
1874<div class="doc_code">
1875<pre>
1876%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1877</pre>
1878</div>
1879
1880<p>
1881Inline asms with side effects not visible in the constraint list must be marked
1882as having side effects. This is done through the use of the
1883'<tt>sideeffect</tt>' keyword, like so:
1884</p>
1885
1886<div class="doc_code">
1887<pre>
1888call void asm sideeffect "eieio", ""()
1889</pre>
1890</div>
1891
1892<p>TODO: The format of the asm and constraints string still need to be
1893documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]1894need to be documented). This is probably best done by reference to another
1895document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1896</p>
1897
1898</div>
1899
1900<!-- *********************************************************************** -->
1901<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1902<!-- *********************************************************************** -->
1903
1904<div class="doc_text">
1905
1906<p>The LLVM instruction set consists of several different
1907classifications of instructions: <a href="#terminators">terminator
1908instructions</a>, <a href="#binaryops">binary instructions</a>,
1909<a href="#bitwiseops">bitwise binary instructions</a>, <a
1910 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1911instructions</a>.</p>
1912
1913</div>
1914
1915<!-- ======================================================================= -->
1916<div class="doc_subsection"> <a name="terminators">Terminator
1917Instructions</a> </div>
1918
1919<div class="doc_text">
1920
1921<p>As mentioned <a href="#functionstructure">previously</a>, every
1922basic block in a program ends with a "Terminator" instruction, which
1923indicates which block should be executed after the current block is
1924finished. These terminator instructions typically yield a '<tt>void</tt>'
1925value: they produce control flow, not values (the one exception being
1926the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1927<p>There are six different terminator instructions: the '<a
1928 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1929instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1930the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1931 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1932 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1933
1934</div>
1935
1936<!-- _______________________________________________________________________ -->
1937<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1938Instruction</a> </div>
1939<div class="doc_text">
1940<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1941<pre>
1942 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]1943 ret void <i>; Return from void function</i>
1944</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1945
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1946<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1947
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1948<p>The '<tt>ret</tt>' instruction is used to return control flow (and
1949optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1950<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1951returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1952control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1953
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1954<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1955
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1956<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
1957the return value. The type of the return value must be a
1958'<a href="#t_firstclass">first class</a>' type.</p>
1959
1960<p>A function is not <a href="#wellformed">well formed</a> if
1961it it has a non-void return type and contains a '<tt>ret</tt>'
1962instruction with no return value or a return value with a type that
1963does not match its type, or if it has a void return type and contains
1964a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1965
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1966<h5>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1967
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1968<p>When the '<tt>ret</tt>' instruction is executed, control flow
1969returns back to the calling function's context. If the caller is a "<a
1970 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1971the instruction after the call. If the caller was an "<a
1972 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1973at the beginning of the "normal" destination block. If the instruction
1974returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1975return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1976
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1977<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1978
1979<pre>
1980 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1981 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1982 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]1983</pre>
1984</div>
1985<!-- _______________________________________________________________________ -->
1986<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
1987<div class="doc_text">
1988<h5>Syntax:</h5>
1989<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
1990</pre>
1991<h5>Overview:</h5>
1992<p>The '<tt>br</tt>' instruction is used to cause control flow to
1993transfer to a different basic block in the current function. There are
1994two forms of this instruction, corresponding to a conditional branch
1995and an unconditional branch.</p>
1996<h5>Arguments:</h5>
1997<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1998single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
1999unconditional form of the '<tt>br</tt>' instruction takes a single
2000'<tt>label</tt>' value as a target.</p>
2001<h5>Semantics:</h5>
2002<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2003argument is evaluated. If the value is <tt>true</tt>, control flows
2004to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2005control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2006<h5>Example:</h5>
2007<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
2008 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2009</div>
2010<!-- _______________________________________________________________________ -->
2011<div class="doc_subsubsection">
2012 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2013</div>
2014
2015<div class="doc_text">
2016<h5>Syntax:</h5>
2017
2018<pre>
2019 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2020</pre>
2021
2022<h5>Overview:</h5>
2023
2024<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2025several different places. It is a generalization of the '<tt>br</tt>'
2026instruction, allowing a branch to occur to one of many possible
2027destinations.</p>
2028
2029
2030<h5>Arguments:</h5>
2031
2032<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2033comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2034an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2035table is not allowed to contain duplicate constant entries.</p>
2036
2037<h5>Semantics:</h5>
2038
2039<p>The <tt>switch</tt> instruction specifies a table of values and
2040destinations. When the '<tt>switch</tt>' instruction is executed, this
2041table is searched for the given value. If the value is found, control flow is
2042transfered to the corresponding destination; otherwise, control flow is
2043transfered to the default destination.</p>
2044
2045<h5>Implementation:</h5>
2046
2047<p>Depending on properties of the target machine and the particular
2048<tt>switch</tt> instruction, this instruction may be code generated in different
2049ways. For example, it could be generated as a series of chained conditional
2050branches or with a lookup table.</p>
2051
2052<h5>Example:</h5>
2053
2054<pre>
2055 <i>; Emulate a conditional br instruction</i>
2056 %Val = <a href="#i_zext">zext</a> i1 %value to i32
2057 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
2058
2059 <i>; Emulate an unconditional br instruction</i>
2060 switch i32 0, label %dest [ ]
2061
2062 <i>; Implement a jump table:</i>
2063 switch i32 %val, label %otherwise [ i32 0, label %onzero
2064 i32 1, label %onone
2065 i32 2, label %ontwo ]
2066</pre>
2067</div>
2068
2069<!-- _______________________________________________________________________ -->
2070<div class="doc_subsubsection">
2071 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2072</div>
2073
2074<div class="doc_text">
2075
2076<h5>Syntax:</h5>
2077
2078<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2079 &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]2080 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2081</pre>
2082
2083<h5>Overview:</h5>
2084
2085<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2086function, with the possibility of control flow transfer to either the
2087'<tt>normal</tt>' label or the
2088'<tt>exception</tt>' label. If the callee function returns with the
2089"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2090"normal" label. If the callee (or any indirect callees) returns with the "<a
2091href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2092continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2093
2094<h5>Arguments:</h5>
2095
2096<p>This instruction requires several arguments:</p>
2097
2098<ol>
2099 <li>
2100 The optional "cconv" marker indicates which <a href="#callingconv">calling
2101 convention</a> the call should use. If none is specified, the call defaults
2102 to using C calling conventions.
2103 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2104
2105 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2106 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2107 and '<tt>inreg</tt>' attributes are valid here.</li>
2108
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2109 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2110 function value being invoked. In most cases, this is a direct function
2111 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2112 an arbitrary pointer to function value.
2113 </li>
2114
2115 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2116 function to be invoked. </li>
2117
2118 <li>'<tt>function args</tt>': argument list whose types match the function
2119 signature argument types. If the function signature indicates the function
2120 accepts a variable number of arguments, the extra arguments can be
2121 specified. </li>
2122
2123 <li>'<tt>normal label</tt>': the label reached when the called function
2124 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2125
2126 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2127 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2128
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2129 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2130 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2131 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2132</ol>
2133
2134<h5>Semantics:</h5>
2135
2136<p>This instruction is designed to operate as a standard '<tt><a
2137href="#i_call">call</a></tt>' instruction in most regards. The primary
2138difference is that it establishes an association with a label, which is used by
2139the runtime library to unwind the stack.</p>
2140
2141<p>This instruction is used in languages with destructors to ensure that proper
2142cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2143exception. Additionally, this is important for implementation of
2144'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2145
2146<h5>Example:</h5>
2147<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2148 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2149 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2150 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2151 unwind label %TestCleanup <i>; {i32}:retval set</i>
2152</pre>
2153</div>
2154
2155
2156<!-- _______________________________________________________________________ -->
2157
2158<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2159Instruction</a> </div>
2160
2161<div class="doc_text">
2162
2163<h5>Syntax:</h5>
2164<pre>
2165 unwind
2166</pre>
2167
2168<h5>Overview:</h5>
2169
2170<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2171at the first callee in the dynamic call stack which used an <a
2172href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2173primarily used to implement exception handling.</p>
2174
2175<h5>Semantics:</h5>
2176
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2177<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2178immediately halt. The dynamic call stack is then searched for the first <a
2179href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2180execution continues at the "exceptional" destination block specified by the
2181<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2182dynamic call chain, undefined behavior results.</p>
2183</div>
2184
2185<!-- _______________________________________________________________________ -->
2186
2187<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2188Instruction</a> </div>
2189
2190<div class="doc_text">
2191
2192<h5>Syntax:</h5>
2193<pre>
2194 unreachable
2195</pre>
2196
2197<h5>Overview:</h5>
2198
2199<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2200instruction is used to inform the optimizer that a particular portion of the
2201code is not reachable. This can be used to indicate that the code after a
2202no-return function cannot be reached, and other facts.</p>
2203
2204<h5>Semantics:</h5>
2205
2206<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2207</div>
2208
2209
2210
2211<!-- ======================================================================= -->
2212<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2213<div class="doc_text">
2214<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2215program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2216produce a single value. The operands might represent
2217multiple 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]2218The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2219<p>There are several different binary operators:</p>
2220</div>
2221<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2222<div class="doc_subsubsection">
2223 <a name="i_add">'<tt>add</tt>' Instruction</a>
2224</div>
2225
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2226<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2228<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2229
2230<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2231 &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]2232</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2234<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2236<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2238<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2239
2240<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2241 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2242 <a href="#t_vector">vector</a> values. Both arguments must have identical
2243 types.</p>
2244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2245<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2246
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2247<p>The value produced is the integer or floating point sum of the two
2248operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2249
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2250<p>If an integer sum has unsigned overflow, the result returned is the
2251mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2252the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2253
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2254<p>Because LLVM integers use a two's complement representation, this
2255instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2256
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2257<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2258
2259<pre>
2260 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2261</pre>
2262</div>
2263<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2264<div class="doc_subsubsection">
2265 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2266</div>
2267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2268<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2269
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2270<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2271
2272<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2273 &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]2274</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2275
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2276<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2277
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2278<p>The '<tt>sub</tt>' instruction returns the difference of its two
2279operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2280
2281<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2282'<tt>neg</tt>' instruction present in most other intermediate
2283representations.</p>
2284
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2285<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2286
2287<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2288 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2289 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2290 types.</p>
2291
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2292<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2293
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2294<p>The value produced is the integer or floating point difference of
2295the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2296
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2297<p>If an integer difference has unsigned overflow, the result returned is the
2298mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2299the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2300
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2301<p>Because LLVM integers use a two's complement representation, this
2302instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2303
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2304<h5>Example:</h5>
2305<pre>
2306 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2307 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2308</pre>
2309</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2310
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2311<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2312<div class="doc_subsubsection">
2313 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2314</div>
2315
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2316<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2317
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2318<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2319<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]2320</pre>
2321<h5>Overview:</h5>
2322<p>The '<tt>mul</tt>' instruction returns the product of its two
2323operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2324
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2325<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2326
2327<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2328href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2329or <a href="#t_vector">vector</a> values. Both arguments must have identical
2330types.</p>
2331
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2332<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2333
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2334<p>The value produced is the integer or floating point product of the
2335two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2336
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2337<p>If the result of an integer multiplication has unsigned overflow,
2338the result returned is the mathematical result modulo
23392<sup>n</sup>, where n is the bit width of the result.</p>
2340<p>Because LLVM integers use a two's complement representation, and the
2341result is the same width as the operands, this instruction returns the
2342correct result for both signed and unsigned integers. If a full product
2343(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2344should be sign-extended or zero-extended as appropriate to the
2345width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2346<h5>Example:</h5>
2347<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2348</pre>
2349</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2350
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2351<!-- _______________________________________________________________________ -->
2352<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2353</a></div>
2354<div class="doc_text">
2355<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2356<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]2357</pre>
2358<h5>Overview:</h5>
2359<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2360operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2361
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2362<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2364<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2365<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2366values. Both arguments must have identical types.</p>
2367
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2368<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2369
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2370<p>The value produced is the unsigned integer quotient of the two operands.</p>
2371<p>Note that unsigned integer division and signed integer division are distinct
2372operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2373<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2374<h5>Example:</h5>
2375<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2376</pre>
2377</div>
2378<!-- _______________________________________________________________________ -->
2379<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2380</a> </div>
2381<div class="doc_text">
2382<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2383<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2384 &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]2385</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2386
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2387<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2388
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2389<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2390operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2391
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2392<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2393
2394<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2395<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2396values. Both arguments must have identical types.</p>
2397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2399<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]2400<p>Note that signed integer division and unsigned integer division are distinct
2401operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2402<p>Division by zero leads to undefined behavior. Overflow also leads to
2403undefined behavior; this is a rare case, but can occur, for example,
2404by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2405<h5>Example:</h5>
2406<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2407</pre>
2408</div>
2409<!-- _______________________________________________________________________ -->
2410<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2411Instruction</a> </div>
2412<div class="doc_text">
2413<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2414<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2415 &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]2416</pre>
2417<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2418
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2419<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
2420operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2421
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2422<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2423
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2424<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2425<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2426of floating point values. Both arguments must have identical types.</p>
2427
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2428<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2429
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2430<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2431
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2432<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2433
2434<pre>
2435 &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]2436</pre>
2437</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2439<!-- _______________________________________________________________________ -->
2440<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2441</div>
2442<div class="doc_text">
2443<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2444<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]2445</pre>
2446<h5>Overview:</h5>
2447<p>The '<tt>urem</tt>' instruction returns the remainder from the
2448unsigned division of its two arguments.</p>
2449<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2450<p>The two arguments to the '<tt>urem</tt>' instruction must be
2451<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2452values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2453<h5>Semantics:</h5>
2454<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2455This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2456<p>Note that unsigned integer remainder and signed integer remainder are
2457distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2458<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2459<h5>Example:</h5>
2460<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2461</pre>
2462
2463</div>
2464<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2465<div class="doc_subsubsection">
2466 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2467</div>
2468
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2469<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2471<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2472
2473<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2474 &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]2475</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2477<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2478
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2479<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2480signed division of its two operands. This instruction can also take
2481<a href="#t_vector">vector</a> versions of the values in which case
2482the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2483
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2484<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2485
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2486<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2488values. Both arguments must have identical types.</p>
2489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2490<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2491
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2492<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2493has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2494operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2495a value. For more information about the difference, see <a
2496 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2497Math Forum</a>. For a table of how this is implemented in various languages,
2498please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2499Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2500<p>Note that signed integer remainder and unsigned integer remainder are
2501distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2502<p>Taking the remainder of a division by zero leads to undefined behavior.
2503Overflow also leads to undefined behavior; this is a rare case, but can occur,
2504for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2505(The remainder doesn't actually overflow, but this rule lets srem be
2506implemented using instructions that return both the result of the division
2507and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2508<h5>Example:</h5>
2509<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2510</pre>
2511
2512</div>
2513<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2514<div class="doc_subsubsection">
2515 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2516
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2517<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2518
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2520<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]2521</pre>
2522<h5>Overview:</h5>
2523<p>The '<tt>frem</tt>' instruction returns the remainder from the
2524division of its two operands.</p>
2525<h5>Arguments:</h5>
2526<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2527<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2528of floating point values. Both arguments must have identical types.</p>
2529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2531
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2532<p>This instruction returns the <i>remainder</i> of a division.
2533The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2534
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2535<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2536
2537<pre>
2538 &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]2539</pre>
2540</div>
2541
2542<!-- ======================================================================= -->
2543<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2544Operations</a> </div>
2545<div class="doc_text">
2546<p>Bitwise binary operators are used to do various forms of
2547bit-twiddling in a program. They are generally very efficient
2548instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2549instructions. They require two operands of the same type, execute an operation on them,
2550and 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]2551</div>
2552
2553<!-- _______________________________________________________________________ -->
2554<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2555Instruction</a> </div>
2556<div class="doc_text">
2557<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2558<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]2559</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2560
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2561<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2562
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2563<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2564the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2565
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2566<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2567
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2568<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2569 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2570type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2573
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2574<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2575where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
2576equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2577
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2578<h5>Example:</h5><pre>
2579 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2580 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2581 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2582 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583</pre>
2584</div>
2585<!-- _______________________________________________________________________ -->
2586<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2587Instruction</a> </div>
2588<div class="doc_text">
2589<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2590<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]2591</pre>
2592
2593<h5>Overview:</h5>
2594<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2595operand shifted to the right a specified number of bits with zero fill.</p>
2596
2597<h5>Arguments:</h5>
2598<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2599<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]2600type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2601
2602<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2603
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2604<p>This instruction always performs a logical shift right operation. The most
2605significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2606shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
2607the number of bits in <tt>op1</tt>, the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2608
2609<h5>Example:</h5>
2610<pre>
2611 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2612 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2613 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2614 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2615 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2616</pre>
2617</div>
2618
2619<!-- _______________________________________________________________________ -->
2620<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2621Instruction</a> </div>
2622<div class="doc_text">
2623
2624<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2625<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]2626</pre>
2627
2628<h5>Overview:</h5>
2629<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2630operand shifted to the right a specified number of bits with sign extension.</p>
2631
2632<h5>Arguments:</h5>
2633<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2634<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]2635type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2636
2637<h5>Semantics:</h5>
2638<p>This instruction always performs an arithmetic shift right operation,
2639The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2640of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
2641larger than the number of bits in <tt>op1</tt>, the result is undefined.
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2642</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2643
2644<h5>Example:</h5>
2645<pre>
2646 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2647 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2648 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2649 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2650 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2651</pre>
2652</div>
2653
2654<!-- _______________________________________________________________________ -->
2655<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2656Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2657
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2658<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2659
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2660<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2661
2662<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2663 &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]2664</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2665
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2666<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2667
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2668<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2669its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2672
2673<p>The two arguments to the '<tt>and</tt>' instruction must be
2674<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2675values. Both arguments must have identical types.</p>
2676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2677<h5>Semantics:</h5>
2678<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2679<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2680<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2681<table border="1" cellspacing="0" cellpadding="4">
2682 <tbody>
2683 <tr>
2684 <td>In0</td>
2685 <td>In1</td>
2686 <td>Out</td>
2687 </tr>
2688 <tr>
2689 <td>0</td>
2690 <td>0</td>
2691 <td>0</td>
2692 </tr>
2693 <tr>
2694 <td>0</td>
2695 <td>1</td>
2696 <td>0</td>
2697 </tr>
2698 <tr>
2699 <td>1</td>
2700 <td>0</td>
2701 <td>0</td>
2702 </tr>
2703 <tr>
2704 <td>1</td>
2705 <td>1</td>
2706 <td>1</td>
2707 </tr>
2708 </tbody>
2709</table>
2710</div>
2711<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2712<pre>
2713 &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]2714 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2715 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2716</pre>
2717</div>
2718<!-- _______________________________________________________________________ -->
2719<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2720<div class="doc_text">
2721<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2722<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]2723</pre>
2724<h5>Overview:</h5>
2725<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2726or of its two operands.</p>
2727<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2728
2729<p>The two arguments to the '<tt>or</tt>' instruction must be
2730<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2731values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2732<h5>Semantics:</h5>
2733<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2734<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2735<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2736<table border="1" cellspacing="0" cellpadding="4">
2737 <tbody>
2738 <tr>
2739 <td>In0</td>
2740 <td>In1</td>
2741 <td>Out</td>
2742 </tr>
2743 <tr>
2744 <td>0</td>
2745 <td>0</td>
2746 <td>0</td>
2747 </tr>
2748 <tr>
2749 <td>0</td>
2750 <td>1</td>
2751 <td>1</td>
2752 </tr>
2753 <tr>
2754 <td>1</td>
2755 <td>0</td>
2756 <td>1</td>
2757 </tr>
2758 <tr>
2759 <td>1</td>
2760 <td>1</td>
2761 <td>1</td>
2762 </tr>
2763 </tbody>
2764</table>
2765</div>
2766<h5>Example:</h5>
2767<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2768 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2769 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2770</pre>
2771</div>
2772<!-- _______________________________________________________________________ -->
2773<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2774Instruction</a> </div>
2775<div class="doc_text">
2776<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2777<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]2778</pre>
2779<h5>Overview:</h5>
2780<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2781or of its two operands. The <tt>xor</tt> is used to implement the
2782"one's complement" operation, which is the "~" operator in C.</p>
2783<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2784<p>The two arguments to the '<tt>xor</tt>' instruction must be
2785<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2786values. Both arguments must have identical types.</p>
2787
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2788<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2789
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2790<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2791<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2792<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2793<table border="1" cellspacing="0" cellpadding="4">
2794 <tbody>
2795 <tr>
2796 <td>In0</td>
2797 <td>In1</td>
2798 <td>Out</td>
2799 </tr>
2800 <tr>
2801 <td>0</td>
2802 <td>0</td>
2803 <td>0</td>
2804 </tr>
2805 <tr>
2806 <td>0</td>
2807 <td>1</td>
2808 <td>1</td>
2809 </tr>
2810 <tr>
2811 <td>1</td>
2812 <td>0</td>
2813 <td>1</td>
2814 </tr>
2815 <tr>
2816 <td>1</td>
2817 <td>1</td>
2818 <td>0</td>
2819 </tr>
2820 </tbody>
2821</table>
2822</div>
2823<p> </p>
2824<h5>Example:</h5>
2825<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2826 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2827 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2828 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2829</pre>
2830</div>
2831
2832<!-- ======================================================================= -->
2833<div class="doc_subsection">
2834 <a name="vectorops">Vector Operations</a>
2835</div>
2836
2837<div class="doc_text">
2838
2839<p>LLVM supports several instructions to represent vector operations in a
2840target-independent manner. These instructions cover the element-access and
2841vector-specific operations needed to process vectors effectively. While LLVM
2842does directly support these vector operations, many sophisticated algorithms
2843will want to use target-specific intrinsics to take full advantage of a specific
2844target.</p>
2845
2846</div>
2847
2848<!-- _______________________________________________________________________ -->
2849<div class="doc_subsubsection">
2850 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2851</div>
2852
2853<div class="doc_text">
2854
2855<h5>Syntax:</h5>
2856
2857<pre>
2858 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2859</pre>
2860
2861<h5>Overview:</h5>
2862
2863<p>
2864The '<tt>extractelement</tt>' instruction extracts a single scalar
2865element from a vector at a specified index.
2866</p>
2867
2868
2869<h5>Arguments:</h5>
2870
2871<p>
2872The first operand of an '<tt>extractelement</tt>' instruction is a
2873value of <a href="#t_vector">vector</a> type. The second operand is
2874an index indicating the position from which to extract the element.
2875The index may be a variable.</p>
2876
2877<h5>Semantics:</h5>
2878
2879<p>
2880The result is a scalar of the same type as the element type of
2881<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2882<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2883results are undefined.
2884</p>
2885
2886<h5>Example:</h5>
2887
2888<pre>
2889 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2890</pre>
2891</div>
2892
2893
2894<!-- _______________________________________________________________________ -->
2895<div class="doc_subsubsection">
2896 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2897</div>
2898
2899<div class="doc_text">
2900
2901<h5>Syntax:</h5>
2902
2903<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2904 &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]2905</pre>
2906
2907<h5>Overview:</h5>
2908
2909<p>
2910The '<tt>insertelement</tt>' instruction inserts a scalar
2911element into a vector at a specified index.
2912</p>
2913
2914
2915<h5>Arguments:</h5>
2916
2917<p>
2918The first operand of an '<tt>insertelement</tt>' instruction is a
2919value of <a href="#t_vector">vector</a> type. The second operand is a
2920scalar value whose type must equal the element type of the first
2921operand. The third operand is an index indicating the position at
2922which to insert the value. The index may be a variable.</p>
2923
2924<h5>Semantics:</h5>
2925
2926<p>
2927The result is a vector of the same type as <tt>val</tt>. Its
2928element values are those of <tt>val</tt> except at position
2929<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2930exceeds the length of <tt>val</tt>, the results are undefined.
2931</p>
2932
2933<h5>Example:</h5>
2934
2935<pre>
2936 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2937</pre>
2938</div>
2939
2940<!-- _______________________________________________________________________ -->
2941<div class="doc_subsubsection">
2942 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2943</div>
2944
2945<div class="doc_text">
2946
2947<h5>Syntax:</h5>
2948
2949<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2950 &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]2951</pre>
2952
2953<h5>Overview:</h5>
2954
2955<p>
2956The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2957from two input vectors, returning a vector with the same element type as
2958the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2959</p>
2960
2961<h5>Arguments:</h5>
2962
2963<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2964The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2965with types that match each other. The third argument is a shuffle mask whose
2966element type is always 'i32'. The result of the instruction is a vector whose
2967length is the same as the shuffle mask and whose element type is the same as
2968the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2969</p>
2970
2971<p>
2972The shuffle mask operand is required to be a constant vector with either
2973constant integer or undef values.
2974</p>
2975
2976<h5>Semantics:</h5>
2977
2978<p>
2979The elements of the two input vectors are numbered from left to right across
2980both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2981the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2982gets. The element selector may be undef (meaning "don't care") and the second
2983operand may be undef if performing a shuffle from only one vector.
2984</p>
2985
2986<h5>Example:</h5>
2987
2988<pre>
2989 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2990 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2991 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2992 &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]2993 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
2994 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
2995 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2996 &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]2997</pre>
2998</div>
2999
3000
3001<!-- ======================================================================= -->
3002<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3003 <a name="aggregateops">Aggregate Operations</a>
3004</div>
3005
3006<div class="doc_text">
3007
3008<p>LLVM supports several instructions for working with aggregate values.
3009</p>
3010
3011</div>
3012
3013<!-- _______________________________________________________________________ -->
3014<div class="doc_subsubsection">
3015 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3016</div>
3017
3018<div class="doc_text">
3019
3020<h5>Syntax:</h5>
3021
3022<pre>
3023 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3024</pre>
3025
3026<h5>Overview:</h5>
3027
3028<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3029The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3030or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3031</p>
3032
3033
3034<h5>Arguments:</h5>
3035
3036<p>
3037The first operand of an '<tt>extractvalue</tt>' instruction is a
3038value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3039type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3040in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3041'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3042</p>
3043
3044<h5>Semantics:</h5>
3045
3046<p>
3047The result is the value at the position in the aggregate specified by
3048the index operands.
3049</p>
3050
3051<h5>Example:</h5>
3052
3053<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3054 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3055</pre>
3056</div>
3057
3058
3059<!-- _______________________________________________________________________ -->
3060<div class="doc_subsubsection">
3061 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3062</div>
3063
3064<div class="doc_text">
3065
3066<h5>Syntax:</h5>
3067
3068<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3069 &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]3070</pre>
3071
3072<h5>Overview:</h5>
3073
3074<p>
3075The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3076into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3077</p>
3078
3079
3080<h5>Arguments:</h5>
3081
3082<p>
3083The first operand of an '<tt>insertvalue</tt>' instruction is a
3084value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3085The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3086The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3087indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3088indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3089'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3090The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3091by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3092</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3093
3094<h5>Semantics:</h5>
3095
3096<p>
3097The result is an aggregate of the same type as <tt>val</tt>. Its
3098value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3099specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3100</p>
3101
3102<h5>Example:</h5>
3103
3104<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3105 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3106</pre>
3107</div>
3108
3109
3110<!-- ======================================================================= -->
3111<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3112 <a name="memoryops">Memory Access and Addressing Operations</a>
3113</div>
3114
3115<div class="doc_text">
3116
3117<p>A key design point of an SSA-based representation is how it
3118represents memory. In LLVM, no memory locations are in SSA form, which
3119makes things very simple. This section describes how to read, write,
3120allocate, and free memory in LLVM.</p>
3121
3122</div>
3123
3124<!-- _______________________________________________________________________ -->
3125<div class="doc_subsubsection">
3126 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3127</div>
3128
3129<div class="doc_text">
3130
3131<h5>Syntax:</h5>
3132
3133<pre>
3134 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3135</pre>
3136
3137<h5>Overview:</h5>
3138
3139<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3140heap and returns a pointer to it. The object is always allocated in the generic
3141address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3142
3143<h5>Arguments:</h5>
3144
3145<p>The '<tt>malloc</tt>' instruction allocates
3146<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3147bytes of memory from the operating system and returns a pointer of the
3148appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3149number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3150If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3151be aligned to at least that boundary. If not specified, or if zero, the target can
3152choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153
3154<p>'<tt>type</tt>' must be a sized type.</p>
3155
3156<h5>Semantics:</h5>
3157
3158<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3159a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3160result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161
3162<h5>Example:</h5>
3163
3164<pre>
3165 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3166
3167 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3168 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3169 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3170 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3171 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3172</pre>
3173</div>
3174
3175<!-- _______________________________________________________________________ -->
3176<div class="doc_subsubsection">
3177 <a name="i_free">'<tt>free</tt>' Instruction</a>
3178</div>
3179
3180<div class="doc_text">
3181
3182<h5>Syntax:</h5>
3183
3184<pre>
3185 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3186</pre>
3187
3188<h5>Overview:</h5>
3189
3190<p>The '<tt>free</tt>' instruction returns memory back to the unused
3191memory heap to be reallocated in the future.</p>
3192
3193<h5>Arguments:</h5>
3194
3195<p>'<tt>value</tt>' shall be a pointer value that points to a value
3196that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3197instruction.</p>
3198
3199<h5>Semantics:</h5>
3200
3201<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3202after this instruction executes. If the pointer is null, the operation
3203is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3204
3205<h5>Example:</h5>
3206
3207<pre>
3208 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3209 free [4 x i8]* %array
3210</pre>
3211</div>
3212
3213<!-- _______________________________________________________________________ -->
3214<div class="doc_subsubsection">
3215 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3216</div>
3217
3218<div class="doc_text">
3219
3220<h5>Syntax:</h5>
3221
3222<pre>
3223 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3224</pre>
3225
3226<h5>Overview:</h5>
3227
3228<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3229currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3230returns to its caller. The object is always allocated in the generic address
3231space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3232
3233<h5>Arguments:</h5>
3234
3235<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3236bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3237appropriate type to the program. If "NumElements" is specified, it is the
3238number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3239If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3240to be aligned to at least that boundary. If not specified, or if zero, the target
3241can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3242
3243<p>'<tt>type</tt>' may be any sized type.</p>
3244
3245<h5>Semantics:</h5>
3246
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3247<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3248there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3249memory is automatically released when the function returns. The '<tt>alloca</tt>'
3250instruction is commonly used to represent automatic variables that must
3251have an address available. When the function returns (either with the <tt><a
3252 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]3253instructions), the memory is reclaimed. Allocating zero bytes
3254is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3255
3256<h5>Example:</h5>
3257
3258<pre>
3259 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3260 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3261 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3262 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3263</pre>
3264</div>
3265
3266<!-- _______________________________________________________________________ -->
3267<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3268Instruction</a> </div>
3269<div class="doc_text">
3270<h5>Syntax:</h5>
3271<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>
3272<h5>Overview:</h5>
3273<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3274<h5>Arguments:</h5>
3275<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3276address from which to load. The pointer must point to a <a
3277 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3278marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3279the number or order of execution of this <tt>load</tt> with other
3280volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3281instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3282<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3283The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3284(that is, the alignment of the memory address). A value of 0 or an
3285omitted "align" argument means that the operation has the preferential
3286alignment for the target. It is the responsibility of the code emitter
3287to ensure that the alignment information is correct. Overestimating
3288the alignment results in an undefined behavior. Underestimating the
3289alignment may produce less efficient code. An alignment of 1 is always
3290safe.
3291</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3292<h5>Semantics:</h5>
3293<p>The location of memory pointed to is loaded.</p>
3294<h5>Examples:</h5>
3295<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3296 <a
3297 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3298 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3299</pre>
3300</div>
3301<!-- _______________________________________________________________________ -->
3302<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3303Instruction</a> </div>
3304<div class="doc_text">
3305<h5>Syntax:</h5>
3306<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3307 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3308</pre>
3309<h5>Overview:</h5>
3310<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3311<h5>Arguments:</h5>
3312<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3313to 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]3314operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3315of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3316operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3317optimizer is not allowed to modify the number or order of execution of
3318this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3319 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3320<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3321The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3322(that is, the alignment of the memory address). A value of 0 or an
3323omitted "align" argument means that the operation has the preferential
3324alignment for the target. It is the responsibility of the code emitter
3325to ensure that the alignment information is correct. Overestimating
3326the alignment results in an undefined behavior. Underestimating the
3327alignment may produce less efficient code. An alignment of 1 is always
3328safe.
3329</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3330<h5>Semantics:</h5>
3331<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3332at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3333<h5>Example:</h5>
3334<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3335 store i32 3, i32* %ptr <i>; yields {void}</i>
3336 %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]3337</pre>
3338</div>
3339
3340<!-- _______________________________________________________________________ -->
3341<div class="doc_subsubsection">
3342 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3343</div>
3344
3345<div class="doc_text">
3346<h5>Syntax:</h5>
3347<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3348 &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]3349</pre>
3350
3351<h5>Overview:</h5>
3352
3353<p>
3354The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3355subelement of an aggregate data structure. It performs address calculation only
3356and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3357
3358<h5>Arguments:</h5>
3359
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3360<p>The first argument is always a pointer, and forms the basis of the
3361calculation. The remaining arguments are indices, that indicate which of the
3362elements of the aggregate object are indexed. The interpretation of each index
3363is dependent on the type being indexed into. The first index always indexes the
3364pointer value given as the first argument, the second index indexes a value of
3365the type pointed to (not necessarily the value directly pointed to, since the
3366first index can be non-zero), etc. The first type indexed into must be a pointer
3367value, subsequent types can be arrays, vectors and structs. Note that subsequent
3368types being indexed into can never be pointers, since that would require loading
3369the pointer before continuing calculation.</p>
3370
3371<p>The type of each index argument depends on the type it is indexing into.
3372When indexing into a (packed) structure, only <tt>i32</tt> integer
3373<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3374only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3375will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376
3377<p>For example, let's consider a C code fragment and how it gets
3378compiled to LLVM:</p>
3379
3380<div class="doc_code">
3381<pre>
3382struct RT {
3383 char A;
3384 int B[10][20];
3385 char C;
3386};
3387struct ST {
3388 int X;
3389 double Y;
3390 struct RT Z;
3391};
3392
3393int *foo(struct ST *s) {
3394 return &amp;s[1].Z.B[5][13];
3395}
3396</pre>
3397</div>
3398
3399<p>The LLVM code generated by the GCC frontend is:</p>
3400
3401<div class="doc_code">
3402<pre>
3403%RT = type { i8 , [10 x [20 x i32]], i8 }
3404%ST = type { i32, double, %RT }
3405
3406define i32* %foo(%ST* %s) {
3407entry:
3408 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3409 ret i32* %reg
3410}
3411</pre>
3412</div>
3413
3414<h5>Semantics:</h5>
3415
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3416<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3417type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3418}</tt>' type, a structure. The second index indexes into the third element of
3419the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3420i8 }</tt>' type, another structure. The third index indexes into the second
3421element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3422array. The two dimensions of the array are subscripted into, yielding an
3423'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3424to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3425
3426<p>Note that it is perfectly legal to index partially through a
3427structure, returning a pointer to an inner element. Because of this,
3428the LLVM code for the given testcase is equivalent to:</p>
3429
3430<pre>
3431 define i32* %foo(%ST* %s) {
3432 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3433 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3434 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3435 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3436 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3437 ret i32* %t5
3438 }
3439</pre>
3440
3441<p>Note that it is undefined to access an array out of bounds: array and
3442pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3443The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3444defined to be accessible as variable length arrays, which requires access
3445beyond the zero'th element.</p>
3446
3447<p>The getelementptr instruction is often confusing. For some more insight
3448into how it works, see <a href="GetElementPtr.html">the getelementptr
3449FAQ</a>.</p>
3450
3451<h5>Example:</h5>
3452
3453<pre>
3454 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3455 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3456 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3457 %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]3458 <i>; yields i8*:eptr</i>
3459 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3460</pre>
3461</div>
3462
3463<!-- ======================================================================= -->
3464<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3465</div>
3466<div class="doc_text">
3467<p>The instructions in this category are the conversion instructions (casting)
3468which all take a single operand and a type. They perform various bit conversions
3469on the operand.</p>
3470</div>
3471
3472<!-- _______________________________________________________________________ -->
3473<div class="doc_subsubsection">
3474 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3475</div>
3476<div class="doc_text">
3477
3478<h5>Syntax:</h5>
3479<pre>
3480 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3481</pre>
3482
3483<h5>Overview:</h5>
3484<p>
3485The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3486</p>
3487
3488<h5>Arguments:</h5>
3489<p>
3490The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3491be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3492and type of the result, which must be an <a href="#t_integer">integer</a>
3493type. The bit size of <tt>value</tt> must be larger than the bit size of
3494<tt>ty2</tt>. Equal sized types are not allowed.</p>
3495
3496<h5>Semantics:</h5>
3497<p>
3498The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3499and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3500larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3501It will always truncate bits.</p>
3502
3503<h5>Example:</h5>
3504<pre>
3505 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3506 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3507 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3508</pre>
3509</div>
3510
3511<!-- _______________________________________________________________________ -->
3512<div class="doc_subsubsection">
3513 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3514</div>
3515<div class="doc_text">
3516
3517<h5>Syntax:</h5>
3518<pre>
3519 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3520</pre>
3521
3522<h5>Overview:</h5>
3523<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3524<tt>ty2</tt>.</p>
3525
3526
3527<h5>Arguments:</h5>
3528<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3529<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3530also be of <a href="#t_integer">integer</a> type. The bit size of the
3531<tt>value</tt> must be smaller than the bit size of the destination type,
3532<tt>ty2</tt>.</p>
3533
3534<h5>Semantics:</h5>
3535<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3536bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3537
3538<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3539
3540<h5>Example:</h5>
3541<pre>
3542 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3543 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3544</pre>
3545</div>
3546
3547<!-- _______________________________________________________________________ -->
3548<div class="doc_subsubsection">
3549 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3550</div>
3551<div class="doc_text">
3552
3553<h5>Syntax:</h5>
3554<pre>
3555 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3556</pre>
3557
3558<h5>Overview:</h5>
3559<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3560
3561<h5>Arguments:</h5>
3562<p>
3563The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3564<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3565also be of <a href="#t_integer">integer</a> type. The bit size of the
3566<tt>value</tt> must be smaller than the bit size of the destination type,
3567<tt>ty2</tt>.</p>
3568
3569<h5>Semantics:</h5>
3570<p>
3571The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3572bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3573the type <tt>ty2</tt>.</p>
3574
3575<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3576
3577<h5>Example:</h5>
3578<pre>
3579 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3580 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3581</pre>
3582</div>
3583
3584<!-- _______________________________________________________________________ -->
3585<div class="doc_subsubsection">
3586 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3587</div>
3588
3589<div class="doc_text">
3590
3591<h5>Syntax:</h5>
3592
3593<pre>
3594 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3595</pre>
3596
3597<h5>Overview:</h5>
3598<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3599<tt>ty2</tt>.</p>
3600
3601
3602<h5>Arguments:</h5>
3603<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3604 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3605cast it to. The size of <tt>value</tt> must be larger than the size of
3606<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3607<i>no-op cast</i>.</p>
3608
3609<h5>Semantics:</h5>
3610<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3611<a href="#t_floating">floating point</a> type to a smaller
3612<a href="#t_floating">floating point</a> type. If the value cannot fit within
3613the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3614
3615<h5>Example:</h5>
3616<pre>
3617 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3618 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3619</pre>
3620</div>
3621
3622<!-- _______________________________________________________________________ -->
3623<div class="doc_subsubsection">
3624 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3625</div>
3626<div class="doc_text">
3627
3628<h5>Syntax:</h5>
3629<pre>
3630 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3631</pre>
3632
3633<h5>Overview:</h5>
3634<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3635floating point value.</p>
3636
3637<h5>Arguments:</h5>
3638<p>The '<tt>fpext</tt>' instruction takes a
3639<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3640and a <a href="#t_floating">floating point</a> type to cast it to. The source
3641type must be smaller than the destination type.</p>
3642
3643<h5>Semantics:</h5>
3644<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3645<a href="#t_floating">floating point</a> type to a larger
3646<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3647used to make a <i>no-op cast</i> because it always changes bits. Use
3648<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3649
3650<h5>Example:</h5>
3651<pre>
3652 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3653 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3654</pre>
3655</div>
3656
3657<!-- _______________________________________________________________________ -->
3658<div class="doc_subsubsection">
3659 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3660</div>
3661<div class="doc_text">
3662
3663<h5>Syntax:</h5>
3664<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3665 &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]3666</pre>
3667
3668<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3669<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3670unsigned integer equivalent of type <tt>ty2</tt>.
3671</p>
3672
3673<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3674<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]3675scalar or vector <a href="#t_floating">floating point</a> value, and a type
3676to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3677type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3678vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3679
3680<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3681<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3682<a href="#t_floating">floating point</a> operand into the nearest (rounding
3683towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3684the results are undefined.</p>
3685
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3686<h5>Example:</h5>
3687<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3688 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3689 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3690 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3691</pre>
3692</div>
3693
3694<!-- _______________________________________________________________________ -->
3695<div class="doc_subsubsection">
3696 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3697</div>
3698<div class="doc_text">
3699
3700<h5>Syntax:</h5>
3701<pre>
3702 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3703</pre>
3704
3705<h5>Overview:</h5>
3706<p>The '<tt>fptosi</tt>' instruction converts
3707<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3708</p>
3709
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710<h5>Arguments:</h5>
3711<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]3712scalar or vector <a href="#t_floating">floating point</a> value, and a type
3713to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3714type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3715vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3716
3717<h5>Semantics:</h5>
3718<p>The '<tt>fptosi</tt>' instruction converts its
3719<a href="#t_floating">floating point</a> operand into the nearest (rounding
3720towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3721the results are undefined.</p>
3722
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3723<h5>Example:</h5>
3724<pre>
3725 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3726 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3727 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3728</pre>
3729</div>
3730
3731<!-- _______________________________________________________________________ -->
3732<div class="doc_subsubsection">
3733 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3734</div>
3735<div class="doc_text">
3736
3737<h5>Syntax:</h5>
3738<pre>
3739 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3740</pre>
3741
3742<h5>Overview:</h5>
3743<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3744integer and converts that value to the <tt>ty2</tt> type.</p>
3745
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3747<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3748scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3749to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3750type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3751floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3752
3753<h5>Semantics:</h5>
3754<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3755integer quantity and converts it to the corresponding floating point value. If
3756the value cannot fit in the floating point value, the results are undefined.</p>
3757
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3758<h5>Example:</h5>
3759<pre>
3760 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3761 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3762</pre>
3763</div>
3764
3765<!-- _______________________________________________________________________ -->
3766<div class="doc_subsubsection">
3767 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3768</div>
3769<div class="doc_text">
3770
3771<h5>Syntax:</h5>
3772<pre>
3773 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3774</pre>
3775
3776<h5>Overview:</h5>
3777<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3778integer and converts that value to the <tt>ty2</tt> type.</p>
3779
3780<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3781<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3782scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3783to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3784type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3785floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3786
3787<h5>Semantics:</h5>
3788<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3789integer quantity and converts it to the corresponding floating point value. If
3790the value cannot fit in the floating point value, the results are undefined.</p>
3791
3792<h5>Example:</h5>
3793<pre>
3794 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3795 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3796</pre>
3797</div>
3798
3799<!-- _______________________________________________________________________ -->
3800<div class="doc_subsubsection">
3801 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3802</div>
3803<div class="doc_text">
3804
3805<h5>Syntax:</h5>
3806<pre>
3807 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3808</pre>
3809
3810<h5>Overview:</h5>
3811<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3812the integer type <tt>ty2</tt>.</p>
3813
3814<h5>Arguments:</h5>
3815<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3816must 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]3817<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]3818
3819<h5>Semantics:</h5>
3820<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3821<tt>ty2</tt> by interpreting the pointer value as an integer and either
3822truncating or zero extending that value to the size of the integer type. If
3823<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3824<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3825are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3826change.</p>
3827
3828<h5>Example:</h5>
3829<pre>
3830 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3831 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3832</pre>
3833</div>
3834
3835<!-- _______________________________________________________________________ -->
3836<div class="doc_subsubsection">
3837 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3838</div>
3839<div class="doc_text">
3840
3841<h5>Syntax:</h5>
3842<pre>
3843 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3844</pre>
3845
3846<h5>Overview:</h5>
3847<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3848a pointer type, <tt>ty2</tt>.</p>
3849
3850<h5>Arguments:</h5>
3851<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3852value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3853<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3854
3855<h5>Semantics:</h5>
3856<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3857<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3858the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3859size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3860the size of a pointer then a zero extension is done. If they are the same size,
3861nothing is done (<i>no-op cast</i>).</p>
3862
3863<h5>Example:</h5>
3864<pre>
3865 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3866 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3867 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3868</pre>
3869</div>
3870
3871<!-- _______________________________________________________________________ -->
3872<div class="doc_subsubsection">
3873 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3874</div>
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
3878<pre>
3879 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3880</pre>
3881
3882<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3883
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3884<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3885<tt>ty2</tt> without changing any bits.</p>
3886
3887<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3888
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3889<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3890a non-aggregate first class value, and a type to cast it to, which must also be
3891a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3892<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3893and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3894type is a pointer, the destination type must also be a pointer. This
3895instruction supports bitwise conversion of vectors to integers and to vectors
3896of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3897
3898<h5>Semantics:</h5>
3899<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3900<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3901this conversion. The conversion is done as if the <tt>value</tt> had been
3902stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3903converted to other pointer types with this instruction. To convert pointers to
3904other types, use the <a href="#i_inttoptr">inttoptr</a> or
3905<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3906
3907<h5>Example:</h5>
3908<pre>
3909 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3910 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3911 %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]3912</pre>
3913</div>
3914
3915<!-- ======================================================================= -->
3916<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3917<div class="doc_text">
3918<p>The instructions in this category are the "miscellaneous"
3919instructions, which defy better classification.</p>
3920</div>
3921
3922<!-- _______________________________________________________________________ -->
3923<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3924</div>
3925<div class="doc_text">
3926<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3927<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]3928</pre>
3929<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3930<p>The '<tt>icmp</tt>' instruction returns a boolean value or
3931a vector of boolean values based on comparison
3932of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3933<h5>Arguments:</h5>
3934<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3935the condition code indicating the kind of comparison to perform. It is not
3936a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3937</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3938<ol>
3939 <li><tt>eq</tt>: equal</li>
3940 <li><tt>ne</tt>: not equal </li>
3941 <li><tt>ugt</tt>: unsigned greater than</li>
3942 <li><tt>uge</tt>: unsigned greater or equal</li>
3943 <li><tt>ult</tt>: unsigned less than</li>
3944 <li><tt>ule</tt>: unsigned less or equal</li>
3945 <li><tt>sgt</tt>: signed greater than</li>
3946 <li><tt>sge</tt>: signed greater or equal</li>
3947 <li><tt>slt</tt>: signed less than</li>
3948 <li><tt>sle</tt>: signed less or equal</li>
3949</ol>
3950<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3951<a href="#t_pointer">pointer</a>
3952or integer <a href="#t_vector">vector</a> typed.
3953They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3954<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3955<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]3956the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3957yields 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]3958</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3959<ol>
3960 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3961 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3962 </li>
3963 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3964 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3966 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3967 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3968 <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]3969 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3970 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3971 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3972 <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]3973 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3974 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3975 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3976 <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]3977 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3978 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3979 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3980 <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]3981</ol>
3982<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3983values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3984<p>If the operands are integer vectors, then they are compared
3985element by element. The result is an <tt>i1</tt> vector with
3986the same number of elements as the values being compared.
3987Otherwise, the result is an <tt>i1</tt>.
3988</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3989
3990<h5>Example:</h5>
3991<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3992 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3993 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3994 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3995 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3996 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
3997</pre>
3998</div>
3999
4000<!-- _______________________________________________________________________ -->
4001<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4002</div>
4003<div class="doc_text">
4004<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4005<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]4006</pre>
4007<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4008<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4009or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4010of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4011<p>
4012If the operands are floating point scalars, then the result
4013type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4014</p>
4015<p>If the operands are floating point vectors, then the result type
4016is a vector of boolean with the same number of elements as the
4017operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4018<h5>Arguments:</h5>
4019<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4020the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4021a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4022<ol>
4023 <li><tt>false</tt>: no comparison, always returns false</li>
4024 <li><tt>oeq</tt>: ordered and equal</li>
4025 <li><tt>ogt</tt>: ordered and greater than </li>
4026 <li><tt>oge</tt>: ordered and greater than or equal</li>
4027 <li><tt>olt</tt>: ordered and less than </li>
4028 <li><tt>ole</tt>: ordered and less than or equal</li>
4029 <li><tt>one</tt>: ordered and not equal</li>
4030 <li><tt>ord</tt>: ordered (no nans)</li>
4031 <li><tt>ueq</tt>: unordered or equal</li>
4032 <li><tt>ugt</tt>: unordered or greater than </li>
4033 <li><tt>uge</tt>: unordered or greater than or equal</li>
4034 <li><tt>ult</tt>: unordered or less than </li>
4035 <li><tt>ule</tt>: unordered or less than or equal</li>
4036 <li><tt>une</tt>: unordered or not equal</li>
4037 <li><tt>uno</tt>: unordered (either nans)</li>
4038 <li><tt>true</tt>: no comparison, always returns true</li>
4039</ol>
4040<p><i>Ordered</i> means that neither operand is a QNAN while
4041<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4042<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4043either a <a href="#t_floating">floating point</a> type
4044or a <a href="#t_vector">vector</a> of floating point type.
4045They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4046<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4047<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4048according to the condition code given as <tt>cond</tt>.
4049If the operands are vectors, then the vectors are compared
4050element by element.
4051Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4052always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4053<ol>
4054 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4055 <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]4056 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057 <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]4058 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4059 <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]4060 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4061 <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]4062 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4063 <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]4064 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065 <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]4066 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4067 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4068 <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]4069 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070 <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]4071 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4072 <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]4073 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074 <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]4075 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076 <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]4077 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078 <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]4079 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4081 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4082</ol>
4083
4084<h5>Example:</h5>
4085<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]4086 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4087 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4088 &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]4089</pre>
4090</div>
4091
4092<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4093<div class="doc_subsubsection">
4094 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4095</div>
4096<div class="doc_text">
4097<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4098<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]4099</pre>
4100<h5>Overview:</h5>
4101<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4102element-wise comparison of its two integer vector operands.</p>
4103<h5>Arguments:</h5>
4104<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4105the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4106a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4107<ol>
4108 <li><tt>eq</tt>: equal</li>
4109 <li><tt>ne</tt>: not equal </li>
4110 <li><tt>ugt</tt>: unsigned greater than</li>
4111 <li><tt>uge</tt>: unsigned greater or equal</li>
4112 <li><tt>ult</tt>: unsigned less than</li>
4113 <li><tt>ule</tt>: unsigned less or equal</li>
4114 <li><tt>sgt</tt>: signed greater than</li>
4115 <li><tt>sge</tt>: signed greater or equal</li>
4116 <li><tt>slt</tt>: signed less than</li>
4117 <li><tt>sle</tt>: signed less or equal</li>
4118</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4119<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4120<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4121<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4122<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4123according to the condition code given as <tt>cond</tt>. The comparison yields a
4124<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4125identical type as the values being compared. The most significant bit in each
4126element is 1 if the element-wise comparison evaluates to true, and is 0
4127otherwise. All other bits of the result are undefined. The condition codes
4128are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4129instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4130
4131<h5>Example:</h5>
4132<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4133 &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>
4134 &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]4135</pre>
4136</div>
4137
4138<!-- _______________________________________________________________________ -->
4139<div class="doc_subsubsection">
4140 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4141</div>
4142<div class="doc_text">
4143<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4144<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]4145<h5>Overview:</h5>
4146<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4147element-wise comparison of its two floating point vector operands. The output
4148elements have the same width as the input elements.</p>
4149<h5>Arguments:</h5>
4150<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4151the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4152a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4153<ol>
4154 <li><tt>false</tt>: no comparison, always returns false</li>
4155 <li><tt>oeq</tt>: ordered and equal</li>
4156 <li><tt>ogt</tt>: ordered and greater than </li>
4157 <li><tt>oge</tt>: ordered and greater than or equal</li>
4158 <li><tt>olt</tt>: ordered and less than </li>
4159 <li><tt>ole</tt>: ordered and less than or equal</li>
4160 <li><tt>one</tt>: ordered and not equal</li>
4161 <li><tt>ord</tt>: ordered (no nans)</li>
4162 <li><tt>ueq</tt>: unordered or equal</li>
4163 <li><tt>ugt</tt>: unordered or greater than </li>
4164 <li><tt>uge</tt>: unordered or greater than or equal</li>
4165 <li><tt>ult</tt>: unordered or less than </li>
4166 <li><tt>ule</tt>: unordered or less than or equal</li>
4167 <li><tt>une</tt>: unordered or not equal</li>
4168 <li><tt>uno</tt>: unordered (either nans)</li>
4169 <li><tt>true</tt>: no comparison, always returns true</li>
4170</ol>
4171<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4172<a href="#t_floating">floating point</a> typed. They must also be identical
4173types.</p>
4174<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4175<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4176according to the condition code given as <tt>cond</tt>. The comparison yields a
4177<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4178an identical number of elements as the values being compared, and each element
4179having identical with to the width of the floating point elements. The most
4180significant bit in each element is 1 if the element-wise comparison evaluates to
4181true, and is 0 otherwise. All other bits of the result are undefined. The
4182condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4183<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4184
4185<h5>Example:</h5>
4186<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4187 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4188 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4189
4190 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4191 &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]4192</pre>
4193</div>
4194
4195<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4196<div class="doc_subsubsection">
4197 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4198</div>
4199
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4200<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4201
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4202<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4203
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4204<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4205<h5>Overview:</h5>
4206<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4207the SSA graph representing the function.</p>
4208<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4209
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4210<p>The type of the incoming values is specified with the first type
4211field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4212as arguments, with one pair for each predecessor basic block of the
4213current block. Only values of <a href="#t_firstclass">first class</a>
4214type may be used as the value arguments to the PHI node. Only labels
4215may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4216
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4217<p>There must be no non-phi instructions between the start of a basic
4218block and the PHI instructions: i.e. PHI instructions must be first in
4219a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4223<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4224specified by the pair corresponding to the predecessor basic block that executed
4225just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4226
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4227<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4228<pre>
4229Loop: ; Infinite loop that counts from 0 on up...
4230 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4231 %nextindvar = add i32 %indvar, 1
4232 br label %Loop
4233</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234</div>
4235
4236<!-- _______________________________________________________________________ -->
4237<div class="doc_subsubsection">
4238 <a name="i_select">'<tt>select</tt>' Instruction</a>
4239</div>
4240
4241<div class="doc_text">
4242
4243<h5>Syntax:</h5>
4244
4245<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4246 &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>
4247
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4248 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4249</pre>
4250
4251<h5>Overview:</h5>
4252
4253<p>
4254The '<tt>select</tt>' instruction is used to choose one value based on a
4255condition, without branching.
4256</p>
4257
4258
4259<h5>Arguments:</h5>
4260
4261<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4262The '<tt>select</tt>' instruction requires an 'i1' value or
4263a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4264condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4265type. If the val1/val2 are vectors and
4266the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4267individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268</p>
4269
4270<h5>Semantics:</h5>
4271
4272<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4273If 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]4274value argument; otherwise, it returns the second value argument.
4275</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4276<p>
4277If the condition is a vector of i1, then the value arguments must
4278be vectors of the same size, and the selection is done element
4279by element.
4280</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4281
4282<h5>Example:</h5>
4283
4284<pre>
4285 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4286</pre>
4287</div>
4288
4289
4290<!-- _______________________________________________________________________ -->
4291<div class="doc_subsubsection">
4292 <a name="i_call">'<tt>call</tt>' Instruction</a>
4293</div>
4294
4295<div class="doc_text">
4296
4297<h5>Syntax:</h5>
4298<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4299 &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]4300</pre>
4301
4302<h5>Overview:</h5>
4303
4304<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4305
4306<h5>Arguments:</h5>
4307
4308<p>This instruction requires several arguments:</p>
4309
4310<ol>
4311 <li>
4312 <p>The optional "tail" marker indicates whether the callee function accesses
4313 any allocas or varargs in the caller. If the "tail" marker is present, the
4314 function call is eligible for tail call optimization. Note that calls may
4315 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4316 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4317 </li>
4318 <li>
4319 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4320 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4321 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4322 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4323
4324 <li>
4325 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4326 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4327 and '<tt>inreg</tt>' attributes are valid here.</p>
4328 </li>
4329
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4330 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4331 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4332 the type of the return value. Functions that return no value are marked
4333 <tt><a href="#t_void">void</a></tt>.</p>
4334 </li>
4335 <li>
4336 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4337 value being invoked. The argument types must match the types implied by
4338 this signature. This type can be omitted if the function is not varargs
4339 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4340 </li>
4341 <li>
4342 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4343 be invoked. In most cases, this is a direct function invocation, but
4344 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4345 to function value.</p>
4346 </li>
4347 <li>
4348 <p>'<tt>function args</tt>': argument list whose types match the
4349 function signature argument types. All arguments must be of
4350 <a href="#t_firstclass">first class</a> type. If the function signature
4351 indicates the function accepts a variable number of arguments, the extra
4352 arguments can be specified.</p>
4353 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4354 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4355 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4356 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4357 '<tt>readnone</tt>' attributes are valid here.</p>
4358 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359</ol>
4360
4361<h5>Semantics:</h5>
4362
4363<p>The '<tt>call</tt>' instruction is used to cause control flow to
4364transfer to a specified function, with its incoming arguments bound to
4365the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4366instruction in the called function, control flow continues with the
4367instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4368function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4369
4370<h5>Example:</h5>
4371
4372<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4373 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4374 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4375 %X = tail call i32 @foo() <i>; yields i32</i>
4376 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4377 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4378
4379 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4380 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4381 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4382 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4383 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4384 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4385</pre>
4386
4387</div>
4388
4389<!-- _______________________________________________________________________ -->
4390<div class="doc_subsubsection">
4391 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4392</div>
4393
4394<div class="doc_text">
4395
4396<h5>Syntax:</h5>
4397
4398<pre>
4399 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4400</pre>
4401
4402<h5>Overview:</h5>
4403
4404<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4405the "variable argument" area of a function call. It is used to implement the
4406<tt>va_arg</tt> macro in C.</p>
4407
4408<h5>Arguments:</h5>
4409
4410<p>This instruction takes a <tt>va_list*</tt> value and the type of
4411the argument. It returns a value of the specified argument type and
4412increments the <tt>va_list</tt> to point to the next argument. The
4413actual type of <tt>va_list</tt> is target specific.</p>
4414
4415<h5>Semantics:</h5>
4416
4417<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4418type from the specified <tt>va_list</tt> and causes the
4419<tt>va_list</tt> to point to the next argument. For more information,
4420see the variable argument handling <a href="#int_varargs">Intrinsic
4421Functions</a>.</p>
4422
4423<p>It is legal for this instruction to be called in a function which does not
4424take a variable number of arguments, for example, the <tt>vfprintf</tt>
4425function.</p>
4426
4427<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4428href="#intrinsics">intrinsic function</a> because it takes a type as an
4429argument.</p>
4430
4431<h5>Example:</h5>
4432
4433<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4434
4435</div>
4436
4437<!-- *********************************************************************** -->
4438<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4439<!-- *********************************************************************** -->
4440
4441<div class="doc_text">
4442
4443<p>LLVM supports the notion of an "intrinsic function". These functions have
4444well known names and semantics and are required to follow certain restrictions.
4445Overall, these intrinsics represent an extension mechanism for the LLVM
4446language that does not require changing all of the transformations in LLVM when
4447adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4448
4449<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4450prefix is reserved in LLVM for intrinsic names; thus, function names may not
4451begin with this prefix. Intrinsic functions must always be external functions:
4452you cannot define the body of intrinsic functions. Intrinsic functions may
4453only be used in call or invoke instructions: it is illegal to take the address
4454of an intrinsic function. Additionally, because intrinsic functions are part
4455of the LLVM language, it is required if any are added that they be documented
4456here.</p>
4457
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4458<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4459a family of functions that perform the same operation but on different data
4460types. Because LLVM can represent over 8 million different integer types,
4461overloading is used commonly to allow an intrinsic function to operate on any
4462integer type. One or more of the argument types or the result type can be
4463overloaded to accept any integer type. Argument types may also be defined as
4464exactly matching a previous argument's type or the result type. This allows an
4465intrinsic function which accepts multiple arguments, but needs all of them to
4466be of the same type, to only be overloaded with respect to a single argument or
4467the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4468
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4469<p>Overloaded intrinsics will have the names of its overloaded argument types
4470encoded into its function name, each preceded by a period. Only those types
4471which are overloaded result in a name suffix. Arguments whose type is matched
4472against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4473take an integer of any width and returns an integer of exactly the same integer
4474width. This leads to a family of functions such as
4475<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4476Only one type, the return type, is overloaded, and only one type suffix is
4477required. Because the argument's type is matched against the return type, it
4478does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4479
4480<p>To learn how to add an intrinsic function, please see the
4481<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4482</p>
4483
4484</div>
4485
4486<!-- ======================================================================= -->
4487<div class="doc_subsection">
4488 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4489</div>
4490
4491<div class="doc_text">
4492
4493<p>Variable argument support is defined in LLVM with the <a
4494 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4495intrinsic functions. These functions are related to the similarly
4496named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4497
4498<p>All of these functions operate on arguments that use a
4499target-specific value type "<tt>va_list</tt>". The LLVM assembly
4500language reference manual does not define what this type is, so all
4501transformations should be prepared to handle these functions regardless of
4502the type used.</p>
4503
4504<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4505instruction and the variable argument handling intrinsic functions are
4506used.</p>
4507
4508<div class="doc_code">
4509<pre>
4510define i32 @test(i32 %X, ...) {
4511 ; Initialize variable argument processing
4512 %ap = alloca i8*
4513 %ap2 = bitcast i8** %ap to i8*
4514 call void @llvm.va_start(i8* %ap2)
4515
4516 ; Read a single integer argument
4517 %tmp = va_arg i8** %ap, i32
4518
4519 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4520 %aq = alloca i8*
4521 %aq2 = bitcast i8** %aq to i8*
4522 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4523 call void @llvm.va_end(i8* %aq2)
4524
4525 ; Stop processing of arguments.
4526 call void @llvm.va_end(i8* %ap2)
4527 ret i32 %tmp
4528}
4529
4530declare void @llvm.va_start(i8*)
4531declare void @llvm.va_copy(i8*, i8*)
4532declare void @llvm.va_end(i8*)
4533</pre>
4534</div>
4535
4536</div>
4537
4538<!-- _______________________________________________________________________ -->
4539<div class="doc_subsubsection">
4540 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4541</div>
4542
4543
4544<div class="doc_text">
4545<h5>Syntax:</h5>
4546<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4547<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4548<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4549<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4550href="#i_va_arg">va_arg</a></tt>.</p>
4551
4552<h5>Arguments:</h5>
4553
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4554<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]4555
4556<h5>Semantics:</h5>
4557
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4558<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]4559macro available in C. In a target-dependent way, it initializes the
4560<tt>va_list</tt> element to which the argument points, so that the next call to
4561<tt>va_arg</tt> will produce the first variable argument passed to the function.
4562Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4563last argument of the function as the compiler can figure that out.</p>
4564
4565</div>
4566
4567<!-- _______________________________________________________________________ -->
4568<div class="doc_subsubsection">
4569 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4570</div>
4571
4572<div class="doc_text">
4573<h5>Syntax:</h5>
4574<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4575<h5>Overview:</h5>
4576
4577<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4578which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4579or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4580
4581<h5>Arguments:</h5>
4582
4583<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4584
4585<h5>Semantics:</h5>
4586
4587<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4588macro available in C. In a target-dependent way, it destroys the
4589<tt>va_list</tt> element to which the argument points. Calls to <a
4590href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4591<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4592<tt>llvm.va_end</tt>.</p>
4593
4594</div>
4595
4596<!-- _______________________________________________________________________ -->
4597<div class="doc_subsubsection">
4598 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4599</div>
4600
4601<div class="doc_text">
4602
4603<h5>Syntax:</h5>
4604
4605<pre>
4606 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4607</pre>
4608
4609<h5>Overview:</h5>
4610
4611<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4612from the source argument list to the destination argument list.</p>
4613
4614<h5>Arguments:</h5>
4615
4616<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4617The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4618
4619
4620<h5>Semantics:</h5>
4621
4622<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4623macro available in C. In a target-dependent way, it copies the source
4624<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4625intrinsic is necessary because the <tt><a href="#int_va_start">
4626llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4627example, memory allocation.</p>
4628
4629</div>
4630
4631<!-- ======================================================================= -->
4632<div class="doc_subsection">
4633 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4634</div>
4635
4636<div class="doc_text">
4637
4638<p>
4639LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4640Collection</a> (GC) requires the implementation and generation of these
4641intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4642These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4643stack</a>, as well as garbage collector implementations that require <a
4644href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4645Front-ends for type-safe garbage collected languages should generate these
4646intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4647href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4648</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4649
4650<p>The garbage collection intrinsics only operate on objects in the generic
4651 address space (address space zero).</p>
4652
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653</div>
4654
4655<!-- _______________________________________________________________________ -->
4656<div class="doc_subsubsection">
4657 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4658</div>
4659
4660<div class="doc_text">
4661
4662<h5>Syntax:</h5>
4663
4664<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4665 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4666</pre>
4667
4668<h5>Overview:</h5>
4669
4670<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4671the code generator, and allows some metadata to be associated with it.</p>
4672
4673<h5>Arguments:</h5>
4674
4675<p>The first argument specifies the address of a stack object that contains the
4676root pointer. The second pointer (which must be either a constant or a global
4677value address) contains the meta-data to be associated with the root.</p>
4678
4679<h5>Semantics:</h5>
4680
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4681<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]4682location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4683the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4684intrinsic may only be used in a function which <a href="#gc">specifies a GC
4685algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4686
4687</div>
4688
4689
4690<!-- _______________________________________________________________________ -->
4691<div class="doc_subsubsection">
4692 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4693</div>
4694
4695<div class="doc_text">
4696
4697<h5>Syntax:</h5>
4698
4699<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4700 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4701</pre>
4702
4703<h5>Overview:</h5>
4704
4705<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4706locations, allowing garbage collector implementations that require read
4707barriers.</p>
4708
4709<h5>Arguments:</h5>
4710
4711<p>The second argument is the address to read from, which should be an address
4712allocated from the garbage collector. The first object is a pointer to the
4713start of the referenced object, if needed by the language runtime (otherwise
4714null).</p>
4715
4716<h5>Semantics:</h5>
4717
4718<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4719instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4720garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4721may only be used in a function which <a href="#gc">specifies a GC
4722algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4723
4724</div>
4725
4726
4727<!-- _______________________________________________________________________ -->
4728<div class="doc_subsubsection">
4729 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4730</div>
4731
4732<div class="doc_text">
4733
4734<h5>Syntax:</h5>
4735
4736<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4737 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4738</pre>
4739
4740<h5>Overview:</h5>
4741
4742<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4743locations, allowing garbage collector implementations that require write
4744barriers (such as generational or reference counting collectors).</p>
4745
4746<h5>Arguments:</h5>
4747
4748<p>The first argument is the reference to store, the second is the start of the
4749object to store it to, and the third is the address of the field of Obj to
4750store to. If the runtime does not require a pointer to the object, Obj may be
4751null.</p>
4752
4753<h5>Semantics:</h5>
4754
4755<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4756instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4757garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4758may only be used in a function which <a href="#gc">specifies a GC
4759algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4760
4761</div>
4762
4763
4764
4765<!-- ======================================================================= -->
4766<div class="doc_subsection">
4767 <a name="int_codegen">Code Generator Intrinsics</a>
4768</div>
4769
4770<div class="doc_text">
4771<p>
4772These intrinsics are provided by LLVM to expose special features that may only
4773be implemented with code generator support.
4774</p>
4775
4776</div>
4777
4778<!-- _______________________________________________________________________ -->
4779<div class="doc_subsubsection">
4780 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4781</div>
4782
4783<div class="doc_text">
4784
4785<h5>Syntax:</h5>
4786<pre>
4787 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4788</pre>
4789
4790<h5>Overview:</h5>
4791
4792<p>
4793The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4794target-specific value indicating the return address of the current function
4795or one of its callers.
4796</p>
4797
4798<h5>Arguments:</h5>
4799
4800<p>
4801The argument to this intrinsic indicates which function to return the address
4802for. Zero indicates the calling function, one indicates its caller, etc. The
4803argument is <b>required</b> to be a constant integer value.
4804</p>
4805
4806<h5>Semantics:</h5>
4807
4808<p>
4809The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4810the return address of the specified call frame, or zero if it cannot be
4811identified. The value returned by this intrinsic is likely to be incorrect or 0
4812for arguments other than zero, so it should only be used for debugging purposes.
4813</p>
4814
4815<p>
4816Note that calling this intrinsic does not prevent function inlining or other
4817aggressive transformations, so the value returned may not be that of the obvious
4818source-language caller.
4819</p>
4820</div>
4821
4822
4823<!-- _______________________________________________________________________ -->
4824<div class="doc_subsubsection">
4825 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4826</div>
4827
4828<div class="doc_text">
4829
4830<h5>Syntax:</h5>
4831<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4832 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4833</pre>
4834
4835<h5>Overview:</h5>
4836
4837<p>
4838The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4839target-specific frame pointer value for the specified stack frame.
4840</p>
4841
4842<h5>Arguments:</h5>
4843
4844<p>
4845The argument to this intrinsic indicates which function to return the frame
4846pointer for. Zero indicates the calling function, one indicates its caller,
4847etc. The argument is <b>required</b> to be a constant integer value.
4848</p>
4849
4850<h5>Semantics:</h5>
4851
4852<p>
4853The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4854the frame address of the specified call frame, or zero if it cannot be
4855identified. The value returned by this intrinsic is likely to be incorrect or 0
4856for arguments other than zero, so it should only be used for debugging purposes.
4857</p>
4858
4859<p>
4860Note that calling this intrinsic does not prevent function inlining or other
4861aggressive transformations, so the value returned may not be that of the obvious
4862source-language caller.
4863</p>
4864</div>
4865
4866<!-- _______________________________________________________________________ -->
4867<div class="doc_subsubsection">
4868 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4869</div>
4870
4871<div class="doc_text">
4872
4873<h5>Syntax:</h5>
4874<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4875 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4876</pre>
4877
4878<h5>Overview:</h5>
4879
4880<p>
4881The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4882the function stack, for use with <a href="#int_stackrestore">
4883<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4884features like scoped automatic variable sized arrays in C99.
4885</p>
4886
4887<h5>Semantics:</h5>
4888
4889<p>
4890This intrinsic returns a opaque pointer value that can be passed to <a
4891href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4892<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4893<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4894state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4895practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4896that were allocated after the <tt>llvm.stacksave</tt> was executed.
4897</p>
4898
4899</div>
4900
4901<!-- _______________________________________________________________________ -->
4902<div class="doc_subsubsection">
4903 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4904</div>
4905
4906<div class="doc_text">
4907
4908<h5>Syntax:</h5>
4909<pre>
4910 declare void @llvm.stackrestore(i8 * %ptr)
4911</pre>
4912
4913<h5>Overview:</h5>
4914
4915<p>
4916The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4917the function stack to the state it was in when the corresponding <a
4918href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4919useful for implementing language features like scoped automatic variable sized
4920arrays in C99.
4921</p>
4922
4923<h5>Semantics:</h5>
4924
4925<p>
4926See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4927</p>
4928
4929</div>
4930
4931
4932<!-- _______________________________________________________________________ -->
4933<div class="doc_subsubsection">
4934 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4935</div>
4936
4937<div class="doc_text">
4938
4939<h5>Syntax:</h5>
4940<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4941 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]4942</pre>
4943
4944<h5>Overview:</h5>
4945
4946
4947<p>
4948The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4949a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4950no
4951effect on the behavior of the program but can change its performance
4952characteristics.
4953</p>
4954
4955<h5>Arguments:</h5>
4956
4957<p>
4958<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4959determining if the fetch should be for a read (0) or write (1), and
4960<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4961locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4962<tt>locality</tt> arguments must be constant integers.
4963</p>
4964
4965<h5>Semantics:</h5>
4966
4967<p>
4968This intrinsic does not modify the behavior of the program. In particular,
4969prefetches cannot trap and do not produce a value. On targets that support this
4970intrinsic, the prefetch can provide hints to the processor cache for better
4971performance.
4972</p>
4973
4974</div>
4975
4976<!-- _______________________________________________________________________ -->
4977<div class="doc_subsubsection">
4978 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4979</div>
4980
4981<div class="doc_text">
4982
4983<h5>Syntax:</h5>
4984<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4985 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4986</pre>
4987
4988<h5>Overview:</h5>
4989
4990
4991<p>
4992The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4993(PC) in a region of
4994code to simulators and other tools. The method is target specific, but it is
4995expected that the marker will use exported symbols to transmit the PC of the
4996marker.
4997The marker makes no guarantees that it will remain with any specific instruction
4998after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4999optimizations. The intended use is to be inserted after optimizations to allow
5000correlations of simulation runs.
5001</p>
5002
5003<h5>Arguments:</h5>
5004
5005<p>
5006<tt>id</tt> is a numerical id identifying the marker.
5007</p>
5008
5009<h5>Semantics:</h5>
5010
5011<p>
5012This intrinsic does not modify the behavior of the program. Backends that do not
5013support this intrinisic may ignore it.
5014</p>
5015
5016</div>
5017
5018<!-- _______________________________________________________________________ -->
5019<div class="doc_subsubsection">
5020 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5021</div>
5022
5023<div class="doc_text">
5024
5025<h5>Syntax:</h5>
5026<pre>
5027 declare i64 @llvm.readcyclecounter( )
5028</pre>
5029
5030<h5>Overview:</h5>
5031
5032
5033<p>
5034The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5035counter register (or similar low latency, high accuracy clocks) on those targets
5036that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5037As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5038should only be used for small timings.
5039</p>
5040
5041<h5>Semantics:</h5>
5042
5043<p>
5044When directly supported, reading the cycle counter should not modify any memory.
5045Implementations are allowed to either return a application specific value or a
5046system wide value. On backends without support, this is lowered to a constant 0.
5047</p>
5048
5049</div>
5050
5051<!-- ======================================================================= -->
5052<div class="doc_subsection">
5053 <a name="int_libc">Standard C Library Intrinsics</a>
5054</div>
5055
5056<div class="doc_text">
5057<p>
5058LLVM provides intrinsics for a few important standard C library functions.
5059These intrinsics allow source-language front-ends to pass information about the
5060alignment of the pointer arguments to the code generator, providing opportunity
5061for more efficient code generation.
5062</p>
5063
5064</div>
5065
5066<!-- _______________________________________________________________________ -->
5067<div class="doc_subsubsection">
5068 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5069</div>
5070
5071<div class="doc_text">
5072
5073<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5074<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5075width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5076<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5077 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5078 i8 &lt;len&gt;, i32 &lt;align&gt;)
5079 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5080 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5081 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5082 i32 &lt;len&gt;, i32 &lt;align&gt;)
5083 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5084 i64 &lt;len&gt;, i32 &lt;align&gt;)
5085</pre>
5086
5087<h5>Overview:</h5>
5088
5089<p>
5090The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5091location to the destination location.
5092</p>
5093
5094<p>
5095Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5096intrinsics do not return a value, and takes an extra alignment argument.
5097</p>
5098
5099<h5>Arguments:</h5>
5100
5101<p>
5102The first argument is a pointer to the destination, the second is a pointer to
5103the source. The third argument is an integer argument
5104specifying the number of bytes to copy, and the fourth argument is the alignment
5105of the source and destination locations.
5106</p>
5107
5108<p>
5109If the call to this intrinisic has an alignment value that is not 0 or 1, then
5110the caller guarantees that both the source and destination pointers are aligned
5111to that boundary.
5112</p>
5113
5114<h5>Semantics:</h5>
5115
5116<p>
5117The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5118location to the destination location, which are not allowed to overlap. It
5119copies "len" bytes of memory over. If the argument is known to be aligned to
5120some boundary, this can be specified as the fourth argument, otherwise it should
5121be set to 0 or 1.
5122</p>
5123</div>
5124
5125
5126<!-- _______________________________________________________________________ -->
5127<div class="doc_subsubsection">
5128 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5129</div>
5130
5131<div class="doc_text">
5132
5133<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5134<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5135width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5136<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5137 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5138 i8 &lt;len&gt;, i32 &lt;align&gt;)
5139 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5140 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5141 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5142 i32 &lt;len&gt;, i32 &lt;align&gt;)
5143 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5144 i64 &lt;len&gt;, i32 &lt;align&gt;)
5145</pre>
5146
5147<h5>Overview:</h5>
5148
5149<p>
5150The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5151location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5152'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5153</p>
5154
5155<p>
5156Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5157intrinsics do not return a value, and takes an extra alignment argument.
5158</p>
5159
5160<h5>Arguments:</h5>
5161
5162<p>
5163The first argument is a pointer to the destination, the second is a pointer to
5164the source. The third argument is an integer argument
5165specifying the number of bytes to copy, and the fourth argument is the alignment
5166of the source and destination locations.
5167</p>
5168
5169<p>
5170If the call to this intrinisic has an alignment value that is not 0 or 1, then
5171the caller guarantees that the source and destination pointers are aligned to
5172that boundary.
5173</p>
5174
5175<h5>Semantics:</h5>
5176
5177<p>
5178The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5179location to the destination location, which may overlap. It
5180copies "len" bytes of memory over. If the argument is known to be aligned to
5181some boundary, this can be specified as the fourth argument, otherwise it should
5182be set to 0 or 1.
5183</p>
5184</div>
5185
5186
5187<!-- _______________________________________________________________________ -->
5188<div class="doc_subsubsection">
5189 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5190</div>
5191
5192<div class="doc_text">
5193
5194<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5195<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5196width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5197<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5198 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5199 i8 &lt;len&gt;, i32 &lt;align&gt;)
5200 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5201 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5202 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5203 i32 &lt;len&gt;, i32 &lt;align&gt;)
5204 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5205 i64 &lt;len&gt;, i32 &lt;align&gt;)
5206</pre>
5207
5208<h5>Overview:</h5>
5209
5210<p>
5211The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5212byte value.
5213</p>
5214
5215<p>
5216Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5217does not return a value, and takes an extra alignment argument.
5218</p>
5219
5220<h5>Arguments:</h5>
5221
5222<p>
5223The first argument is a pointer to the destination to fill, the second is the
5224byte value to fill it with, the third argument is an integer
5225argument specifying the number of bytes to fill, and the fourth argument is the
5226known alignment of destination location.
5227</p>
5228
5229<p>
5230If the call to this intrinisic has an alignment value that is not 0 or 1, then
5231the caller guarantees that the destination pointer is aligned to that boundary.
5232</p>
5233
5234<h5>Semantics:</h5>
5235
5236<p>
5237The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5238the
5239destination location. If the argument is known to be aligned to some boundary,
5240this can be specified as the fourth argument, otherwise it should be set to 0 or
52411.
5242</p>
5243</div>
5244
5245
5246<!-- _______________________________________________________________________ -->
5247<div class="doc_subsubsection">
5248 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5249</div>
5250
5251<div class="doc_text">
5252
5253<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5254<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]5255floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5256types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5257<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5258 declare float @llvm.sqrt.f32(float %Val)
5259 declare double @llvm.sqrt.f64(double %Val)
5260 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5261 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5262 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5263</pre>
5264
5265<h5>Overview:</h5>
5266
5267<p>
5268The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5269returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5270<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5271negative numbers other than -0.0 (which allows for better optimization, because
5272there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5273defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274</p>
5275
5276<h5>Arguments:</h5>
5277
5278<p>
5279The argument and return value are floating point numbers of the same type.
5280</p>
5281
5282<h5>Semantics:</h5>
5283
5284<p>
5285This function returns the sqrt of the specified operand if it is a nonnegative
5286floating point number.
5287</p>
5288</div>
5289
5290<!-- _______________________________________________________________________ -->
5291<div class="doc_subsubsection">
5292 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5293</div>
5294
5295<div class="doc_text">
5296
5297<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5298<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]5299floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5300types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5301<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5302 declare float @llvm.powi.f32(float %Val, i32 %power)
5303 declare double @llvm.powi.f64(double %Val, i32 %power)
5304 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5305 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5306 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5307</pre>
5308
5309<h5>Overview:</h5>
5310
5311<p>
5312The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5313specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5314multiplications is not defined. When a vector of floating point type is
5315used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5316</p>
5317
5318<h5>Arguments:</h5>
5319
5320<p>
5321The second argument is an integer power, and the first is a value to raise to
5322that power.
5323</p>
5324
5325<h5>Semantics:</h5>
5326
5327<p>
5328This function returns the first value raised to the second power with an
5329unspecified sequence of rounding operations.</p>
5330</div>
5331
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5332<!-- _______________________________________________________________________ -->
5333<div class="doc_subsubsection">
5334 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5335</div>
5336
5337<div class="doc_text">
5338
5339<h5>Syntax:</h5>
5340<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5341floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5342types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5343<pre>
5344 declare float @llvm.sin.f32(float %Val)
5345 declare double @llvm.sin.f64(double %Val)
5346 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5347 declare fp128 @llvm.sin.f128(fp128 %Val)
5348 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5349</pre>
5350
5351<h5>Overview:</h5>
5352
5353<p>
5354The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5355</p>
5356
5357<h5>Arguments:</h5>
5358
5359<p>
5360The argument and return value are floating point numbers of the same type.
5361</p>
5362
5363<h5>Semantics:</h5>
5364
5365<p>
5366This function returns the sine of the specified operand, returning the
5367same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5368conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5369</div>
5370
5371<!-- _______________________________________________________________________ -->
5372<div class="doc_subsubsection">
5373 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5374</div>
5375
5376<div class="doc_text">
5377
5378<h5>Syntax:</h5>
5379<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5380floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5381types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5382<pre>
5383 declare float @llvm.cos.f32(float %Val)
5384 declare double @llvm.cos.f64(double %Val)
5385 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5386 declare fp128 @llvm.cos.f128(fp128 %Val)
5387 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5388</pre>
5389
5390<h5>Overview:</h5>
5391
5392<p>
5393The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5394</p>
5395
5396<h5>Arguments:</h5>
5397
5398<p>
5399The argument and return value are floating point numbers of the same type.
5400</p>
5401
5402<h5>Semantics:</h5>
5403
5404<p>
5405This function returns the cosine of the specified operand, returning the
5406same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5407conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5408</div>
5409
5410<!-- _______________________________________________________________________ -->
5411<div class="doc_subsubsection">
5412 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5413</div>
5414
5415<div class="doc_text">
5416
5417<h5>Syntax:</h5>
5418<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5419floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5420types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5421<pre>
5422 declare float @llvm.pow.f32(float %Val, float %Power)
5423 declare double @llvm.pow.f64(double %Val, double %Power)
5424 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5425 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5426 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5427</pre>
5428
5429<h5>Overview:</h5>
5430
5431<p>
5432The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5433specified (positive or negative) power.
5434</p>
5435
5436<h5>Arguments:</h5>
5437
5438<p>
5439The second argument is a floating point power, and the first is a value to
5440raise to that power.
5441</p>
5442
5443<h5>Semantics:</h5>
5444
5445<p>
5446This function returns the first value raised to the second power,
5447returning the
5448same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5449conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5450</div>
5451
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5452
5453<!-- ======================================================================= -->
5454<div class="doc_subsection">
5455 <a name="int_manip">Bit Manipulation Intrinsics</a>
5456</div>
5457
5458<div class="doc_text">
5459<p>
5460LLVM provides intrinsics for a few important bit manipulation operations.
5461These allow efficient code generation for some algorithms.
5462</p>
5463
5464</div>
5465
5466<!-- _______________________________________________________________________ -->
5467<div class="doc_subsubsection">
5468 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5469</div>
5470
5471<div class="doc_text">
5472
5473<h5>Syntax:</h5>
5474<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5475type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5476<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5477 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5478 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5479 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5480</pre>
5481
5482<h5>Overview:</h5>
5483
5484<p>
5485The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5486values with an even number of bytes (positive multiple of 16 bits). These are
5487useful for performing operations on data that is not in the target's native
5488byte order.
5489</p>
5490
5491<h5>Semantics:</h5>
5492
5493<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5494The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5495and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5496intrinsic returns an i32 value that has the four bytes of the input i32
5497swapped, 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]5498i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5499<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5500additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5501</p>
5502
5503</div>
5504
5505<!-- _______________________________________________________________________ -->
5506<div class="doc_subsubsection">
5507 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5508</div>
5509
5510<div class="doc_text">
5511
5512<h5>Syntax:</h5>
5513<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]5514width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5515<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5516 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5517 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5518 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5519 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5520 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5521</pre>
5522
5523<h5>Overview:</h5>
5524
5525<p>
5526The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5527value.
5528</p>
5529
5530<h5>Arguments:</h5>
5531
5532<p>
5533The only argument is the value to be counted. The argument may be of any
5534integer type. The return type must match the argument type.
5535</p>
5536
5537<h5>Semantics:</h5>
5538
5539<p>
5540The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5541</p>
5542</div>
5543
5544<!-- _______________________________________________________________________ -->
5545<div class="doc_subsubsection">
5546 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5547</div>
5548
5549<div class="doc_text">
5550
5551<h5>Syntax:</h5>
5552<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]5553integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5554<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5555 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5556 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5557 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5558 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5559 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5560</pre>
5561
5562<h5>Overview:</h5>
5563
5564<p>
5565The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5566leading zeros in a variable.
5567</p>
5568
5569<h5>Arguments:</h5>
5570
5571<p>
5572The only argument is the value to be counted. The argument may be of any
5573integer type. The return type must match the argument type.
5574</p>
5575
5576<h5>Semantics:</h5>
5577
5578<p>
5579The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5580in a variable. If the src == 0 then the result is the size in bits of the type
5581of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5582</p>
5583</div>
5584
5585
5586
5587<!-- _______________________________________________________________________ -->
5588<div class="doc_subsubsection">
5589 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5590</div>
5591
5592<div class="doc_text">
5593
5594<h5>Syntax:</h5>
5595<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]5596integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5597<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5598 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5599 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5600 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5601 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5602 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5603</pre>
5604
5605<h5>Overview:</h5>
5606
5607<p>
5608The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5609trailing zeros.
5610</p>
5611
5612<h5>Arguments:</h5>
5613
5614<p>
5615The only argument is the value to be counted. The argument may be of any
5616integer type. The return type must match the argument type.
5617</p>
5618
5619<h5>Semantics:</h5>
5620
5621<p>
5622The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5623in a variable. If the src == 0 then the result is the size in bits of the type
5624of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5625</p>
5626</div>
5627
5628<!-- _______________________________________________________________________ -->
5629<div class="doc_subsubsection">
5630 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5631</div>
5632
5633<div class="doc_text">
5634
5635<h5>Syntax:</h5>
5636<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5637on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5638<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5639 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5640 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5641</pre>
5642
5643<h5>Overview:</h5>
5644<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5645range of bits from an integer value and returns them in the same bit width as
5646the original value.</p>
5647
5648<h5>Arguments:</h5>
5649<p>The first argument, <tt>%val</tt> and the result may be integer types of
5650any bit width but they must have the same bit width. The second and third
5651arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5652
5653<h5>Semantics:</h5>
5654<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5655of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5656<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5657operates in forward mode.</p>
5658<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5659right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5660only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5661<ol>
5662 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5663 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5664 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5665 to determine the number of bits to retain.</li>
5666 <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]5667 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5668</ol>
5669<p>In reverse mode, a similar computation is made except that the bits are
5670returned in the reverse order. So, for example, if <tt>X</tt> has the value
5671<tt>i16 0x0ACF (101011001111)</tt> and we apply
5672<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5673<tt>i16 0x0026 (000000100110)</tt>.</p>
5674</div>
5675
5676<div class="doc_subsubsection">
5677 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5678</div>
5679
5680<div class="doc_text">
5681
5682<h5>Syntax:</h5>
5683<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5684on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5685<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5686 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5687 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]5688</pre>
5689
5690<h5>Overview:</h5>
5691<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5692of bits in an integer value with another integer value. It returns the integer
5693with the replaced bits.</p>
5694
5695<h5>Arguments:</h5>
5696<p>The first argument, <tt>%val</tt> and the result may be integer types of
5697any bit width but they must have the same bit width. <tt>%val</tt> is the value
5698whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5699integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5700type since they specify only a bit index.</p>
5701
5702<h5>Semantics:</h5>
5703<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5704of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5705<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5706operates in forward mode.</p>
5707<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5708truncating it down to the size of the replacement area or zero extending it
5709up to that size.</p>
5710<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5711are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5712in <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]5713to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5714<p>In reverse mode, a similar computation is made except that the bits are
5715reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5716<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]5717<h5>Examples:</h5>
5718<pre>
5719 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5720 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5721 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5722 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5723 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5724</pre>
5725</div>
5726
5727<!-- ======================================================================= -->
5728<div class="doc_subsection">
5729 <a name="int_debugger">Debugger Intrinsics</a>
5730</div>
5731
5732<div class="doc_text">
5733<p>
5734The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5735are described in the <a
5736href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5737Debugging</a> document.
5738</p>
5739</div>
5740
5741
5742<!-- ======================================================================= -->
5743<div class="doc_subsection">
5744 <a name="int_eh">Exception Handling Intrinsics</a>
5745</div>
5746
5747<div class="doc_text">
5748<p> The LLVM exception handling intrinsics (which all start with
5749<tt>llvm.eh.</tt> prefix), are described in the <a
5750href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5751Handling</a> document. </p>
5752</div>
5753
5754<!-- ======================================================================= -->
5755<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5756 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5757</div>
5758
5759<div class="doc_text">
5760<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5761 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5762 the <tt>nest</tt> attribute, from a function. The result is a callable
5763 function pointer lacking the nest parameter - the caller does not need
5764 to provide a value for it. Instead, the value to use is stored in
5765 advance in a "trampoline", a block of memory usually allocated
5766 on the stack, which also contains code to splice the nest value into the
5767 argument list. This is used to implement the GCC nested function address
5768 extension.
5769</p>
5770<p>
5771 For example, if the function is
5772 <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]5773 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]5774<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5775 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5776 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5777 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5778 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5779</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5780 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5781 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5782</div>
5783
5784<!-- _______________________________________________________________________ -->
5785<div class="doc_subsubsection">
5786 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5787</div>
5788<div class="doc_text">
5789<h5>Syntax:</h5>
5790<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5791declare 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]5792</pre>
5793<h5>Overview:</h5>
5794<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5795 This fills the memory pointed to by <tt>tramp</tt> with code
5796 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5797</p>
5798<h5>Arguments:</h5>
5799<p>
5800 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5801 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5802 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5803 intrinsic. Note that the size and the alignment are target-specific - LLVM
5804 currently provides no portable way of determining them, so a front-end that
5805 generates this intrinsic needs to have some target-specific knowledge.
5806 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]5807</p>
5808<h5>Semantics:</h5>
5809<p>
5810 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5811 dependent code, turning it into a function. A pointer to this function is
5812 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5813 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5814 before being called. The new function's signature is the same as that of
5815 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5816 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5817 of pointer type. Calling the new function is equivalent to calling
5818 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5819 missing <tt>nest</tt> argument. If, after calling
5820 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5821 modified, then the effect of any later call to the returned function pointer is
5822 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5823</p>
5824</div>
5825
5826<!-- ======================================================================= -->
5827<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5828 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5829</div>
5830
5831<div class="doc_text">
5832<p>
5833 These intrinsic functions expand the "universal IR" of LLVM to represent
5834 hardware constructs for atomic operations and memory synchronization. This
5835 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5836 is aimed at a low enough level to allow any programming models or APIs
5837 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5838 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5839 hardware behavior. Just as hardware provides a "universal IR" for source
5840 languages, it also provides a starting point for developing a "universal"
5841 atomic operation and synchronization IR.
5842</p>
5843<p>
5844 These do <em>not</em> form an API such as high-level threading libraries,
5845 software transaction memory systems, atomic primitives, and intrinsic
5846 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5847 application libraries. The hardware interface provided by LLVM should allow
5848 a clean implementation of all of these APIs and parallel programming models.
5849 No one model or paradigm should be selected above others unless the hardware
5850 itself ubiquitously does so.
5851
5852</p>
5853</div>
5854
5855<!-- _______________________________________________________________________ -->
5856<div class="doc_subsubsection">
5857 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5858</div>
5859<div class="doc_text">
5860<h5>Syntax:</h5>
5861<pre>
5862declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5863i1 &lt;device&gt; )
5864
5865</pre>
5866<h5>Overview:</h5>
5867<p>
5868 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5869 specific pairs of memory access types.
5870</p>
5871<h5>Arguments:</h5>
5872<p>
5873 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5874 The first four arguments enables a specific barrier as listed below. The fith
5875 argument specifies that the barrier applies to io or device or uncached memory.
5876
5877</p>
5878 <ul>
5879 <li><tt>ll</tt>: load-load barrier</li>
5880 <li><tt>ls</tt>: load-store barrier</li>
5881 <li><tt>sl</tt>: store-load barrier</li>
5882 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5883 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5884 </ul>
5885<h5>Semantics:</h5>
5886<p>
5887 This intrinsic causes the system to enforce some ordering constraints upon
5888 the loads and stores of the program. This barrier does not indicate
5889 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5890 which they occur. For any of the specified pairs of load and store operations
5891 (f.ex. load-load, or store-load), all of the first operations preceding the
5892 barrier will complete before any of the second operations succeeding the
5893 barrier begin. Specifically the semantics for each pairing is as follows:
5894</p>
5895 <ul>
5896 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5897 after the barrier begins.</li>
5898
5899 <li><tt>ls</tt>: All loads before the barrier must complete before any
5900 store after the barrier begins.</li>
5901 <li><tt>ss</tt>: All stores before the barrier must complete before any
5902 store after the barrier begins.</li>
5903 <li><tt>sl</tt>: All stores before the barrier must complete before any
5904 load after the barrier begins.</li>
5905 </ul>
5906<p>
5907 These semantics are applied with a logical "and" behavior when more than one
5908 is enabled in a single memory barrier intrinsic.
5909</p>
5910<p>
5911 Backends may implement stronger barriers than those requested when they do not
5912 support as fine grained a barrier as requested. Some architectures do not
5913 need all types of barriers and on such architectures, these become noops.
5914</p>
5915<h5>Example:</h5>
5916<pre>
5917%ptr = malloc i32
5918 store i32 4, %ptr
5919
5920%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5921 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5922 <i>; guarantee the above finishes</i>
5923 store i32 8, %ptr <i>; before this begins</i>
5924</pre>
5925</div>
5926
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5927<!-- _______________________________________________________________________ -->
5928<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5929 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5930</div>
5931<div class="doc_text">
5932<h5>Syntax:</h5>
5933<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5934 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5935 any integer bit width and for different address spaces. Not all targets
5936 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5937
5938<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5939declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5940declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5941declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5942declare 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]5943
5944</pre>
5945<h5>Overview:</h5>
5946<p>
5947 This loads a value in memory and compares it to a given value. If they are
5948 equal, it stores a new value into the memory.
5949</p>
5950<h5>Arguments:</h5>
5951<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5952 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5953 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5954 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5955 this integer type. While any bit width integer may be used, targets may only
5956 lower representations they support in hardware.
5957
5958</p>
5959<h5>Semantics:</h5>
5960<p>
5961 This entire intrinsic must be executed atomically. It first loads the value
5962 in memory pointed to by <tt>ptr</tt> and compares it with the value
5963 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5964 loaded value is yielded in all cases. This provides the equivalent of an
5965 atomic compare-and-swap operation within the SSA framework.
5966</p>
5967<h5>Examples:</h5>
5968
5969<pre>
5970%ptr = malloc i32
5971 store i32 4, %ptr
5972
5973%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5974%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5975 <i>; yields {i32}:result1 = 4</i>
5976%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5977%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5978
5979%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5980%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5981 <i>; yields {i32}:result2 = 8</i>
5982%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5983
5984%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5985</pre>
5986</div>
5987
5988<!-- _______________________________________________________________________ -->
5989<div class="doc_subsubsection">
5990 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
5991</div>
5992<div class="doc_text">
5993<h5>Syntax:</h5>
5994
5995<p>
5996 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
5997 integer bit width. Not all targets support all bit widths however.</p>
5998<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5999declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6000declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6001declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6002declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6003
6004</pre>
6005<h5>Overview:</h5>
6006<p>
6007 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6008 the value from memory. It then stores the value in <tt>val</tt> in the memory
6009 at <tt>ptr</tt>.
6010</p>
6011<h5>Arguments:</h5>
6012
6013<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6014 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6015 <tt>val</tt> argument and the result must be integers of the same bit width.
6016 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6017 integer type. The targets may only lower integer representations they
6018 support.
6019</p>
6020<h5>Semantics:</h5>
6021<p>
6022 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6023 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6024 equivalent of an atomic swap operation within the SSA framework.
6025
6026</p>
6027<h5>Examples:</h5>
6028<pre>
6029%ptr = malloc i32
6030 store i32 4, %ptr
6031
6032%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6033%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6034 <i>; yields {i32}:result1 = 4</i>
6035%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6036%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6037
6038%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6039%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6040 <i>; yields {i32}:result2 = 8</i>
6041
6042%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6043%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6044</pre>
6045</div>
6046
6047<!-- _______________________________________________________________________ -->
6048<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6049 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6050
6051</div>
6052<div class="doc_text">
6053<h5>Syntax:</h5>
6054<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6055 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]6056 integer bit width. Not all targets support all bit widths however.</p>
6057<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6058declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6059declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6060declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6061declare 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]6062
6063</pre>
6064<h5>Overview:</h5>
6065<p>
6066 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6067 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6068</p>
6069<h5>Arguments:</h5>
6070<p>
6071
6072 The intrinsic takes two arguments, the first a pointer to an integer value
6073 and the second an integer value. The result is also an integer value. These
6074 integer types can have any bit width, but they must all have the same bit
6075 width. The targets may only lower integer representations they support.
6076</p>
6077<h5>Semantics:</h5>
6078<p>
6079 This intrinsic does a series of operations atomically. It first loads the
6080 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6081 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6082</p>
6083
6084<h5>Examples:</h5>
6085<pre>
6086%ptr = malloc i32
6087 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6088%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6089 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6090%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6091 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6092%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6093 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6094%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6095</pre>
6096</div>
6097
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6098<!-- _______________________________________________________________________ -->
6099<div class="doc_subsubsection">
6100 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6101
6102</div>
6103<div class="doc_text">
6104<h5>Syntax:</h5>
6105<p>
6106 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]6107 any integer bit width and for different address spaces. Not all targets
6108 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6109<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6110declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6111declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6112declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6113declare 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]6114
6115</pre>
6116<h5>Overview:</h5>
6117<p>
6118 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6119 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6120</p>
6121<h5>Arguments:</h5>
6122<p>
6123
6124 The intrinsic takes two arguments, the first a pointer to an integer value
6125 and the second an integer value. The result is also an integer value. These
6126 integer types can have any bit width, but they must all have the same bit
6127 width. The targets may only lower integer representations they support.
6128</p>
6129<h5>Semantics:</h5>
6130<p>
6131 This intrinsic does a series of operations atomically. It first loads the
6132 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6133 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6134</p>
6135
6136<h5>Examples:</h5>
6137<pre>
6138%ptr = malloc i32
6139 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6140%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6141 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6142%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6143 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6144%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6145 <i>; yields {i32}:result3 = 2</i>
6146%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6147</pre>
6148</div>
6149
6150<!-- _______________________________________________________________________ -->
6151<div class="doc_subsubsection">
6152 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6153 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6154 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6155 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6156
6157</div>
6158<div class="doc_text">
6159<h5>Syntax:</h5>
6160<p>
6161 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6162 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6163 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6164 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6165<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6166declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6167declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6168declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6169declare 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]6170
6171</pre>
6172
6173<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6174declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6175declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6176declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6177declare 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]6178
6179</pre>
6180
6181<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6182declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6183declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6184declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6185declare 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]6186
6187</pre>
6188
6189<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6190declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6191declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6192declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6193declare 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]6194
6195</pre>
6196<h5>Overview:</h5>
6197<p>
6198 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6199 the value stored in memory at <tt>ptr</tt>. It yields the original value
6200 at <tt>ptr</tt>.
6201</p>
6202<h5>Arguments:</h5>
6203<p>
6204
6205 These intrinsics take two arguments, the first a pointer to an integer value
6206 and the second an integer value. The result is also an integer value. These
6207 integer types can have any bit width, but they must all have the same bit
6208 width. The targets may only lower integer representations they support.
6209</p>
6210<h5>Semantics:</h5>
6211<p>
6212 These intrinsics does a series of operations atomically. They first load the
6213 value stored at <tt>ptr</tt>. They then do the bitwise operation
6214 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6215 value stored at <tt>ptr</tt>.
6216</p>
6217
6218<h5>Examples:</h5>
6219<pre>
6220%ptr = malloc i32
6221 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6222%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6223 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6224%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6225 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6226%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6227 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6228%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6229 <i>; yields {i32}:result3 = FF</i>
6230%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6231</pre>
6232</div>
6233
6234
6235<!-- _______________________________________________________________________ -->
6236<div class="doc_subsubsection">
6237 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6238 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6239 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6240 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6241
6242</div>
6243<div class="doc_text">
6244<h5>Syntax:</h5>
6245<p>
6246 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6247 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6248 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6249 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6250 support all bit widths however.</p>
6251<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6252declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6253declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6254declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6255declare 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]6256
6257</pre>
6258
6259<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6260declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6261declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6262declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6263declare 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]6264
6265</pre>
6266
6267<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6268declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6269declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6270declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6271declare 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]6272
6273</pre>
6274
6275<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6276declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6277declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6278declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6279declare 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]6280
6281</pre>
6282<h5>Overview:</h5>
6283<p>
6284 These intrinsics takes the signed or unsigned minimum or maximum of
6285 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6286 original value at <tt>ptr</tt>.
6287</p>
6288<h5>Arguments:</h5>
6289<p>
6290
6291 These intrinsics take two arguments, the first a pointer to an integer value
6292 and the second an integer value. The result is also an integer value. These
6293 integer types can have any bit width, but they must all have the same bit
6294 width. The targets may only lower integer representations they support.
6295</p>
6296<h5>Semantics:</h5>
6297<p>
6298 These intrinsics does a series of operations atomically. They first load the
6299 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6300 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6301 the original value stored at <tt>ptr</tt>.
6302</p>
6303
6304<h5>Examples:</h5>
6305<pre>
6306%ptr = malloc i32
6307 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6308%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6309 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6310%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6311 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6312%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6313 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6314%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6315 <i>; yields {i32}:result3 = 8</i>
6316%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6317</pre>
6318</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6319
6320<!-- ======================================================================= -->
6321<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6322 <a name="int_general">General Intrinsics</a>
6323</div>
6324
6325<div class="doc_text">
6326<p> This class of intrinsics is designed to be generic and has
6327no specific purpose. </p>
6328</div>
6329
6330<!-- _______________________________________________________________________ -->
6331<div class="doc_subsubsection">
6332 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6333</div>
6334
6335<div class="doc_text">
6336
6337<h5>Syntax:</h5>
6338<pre>
6339 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6340</pre>
6341
6342<h5>Overview:</h5>
6343
6344<p>
6345The '<tt>llvm.var.annotation</tt>' intrinsic
6346</p>
6347
6348<h5>Arguments:</h5>
6349
6350<p>
6351The first argument is a pointer to a value, the second is a pointer to a
6352global string, the third is a pointer to a global string which is the source
6353file name, and the last argument is the line number.
6354</p>
6355
6356<h5>Semantics:</h5>
6357
6358<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6359This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6360This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6361annotations. These have no other defined use, they are ignored by code
6362generation and optimization.
6363</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6364</div>
6365
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6366<!-- _______________________________________________________________________ -->
6367<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6368 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6369</div>
6370
6371<div class="doc_text">
6372
6373<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6374<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6375any integer bit width.
6376</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6377<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6378 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6379 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6380 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6381 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6382 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]6383</pre>
6384
6385<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6386
6387<p>
6388The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6389</p>
6390
6391<h5>Arguments:</h5>
6392
6393<p>
6394The first argument is an integer value (result of some expression),
6395the second is a pointer to a global string, the third is a pointer to a global
6396string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6397It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6398</p>
6399
6400<h5>Semantics:</h5>
6401
6402<p>
6403This intrinsic allows annotations to be put on arbitrary expressions
6404with arbitrary strings. This can be useful for special purpose optimizations
6405that want to look for these annotations. These have no other defined use, they
6406are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6407</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6408</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6409
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6410<!-- _______________________________________________________________________ -->
6411<div class="doc_subsubsection">
6412 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6413</div>
6414
6415<div class="doc_text">
6416
6417<h5>Syntax:</h5>
6418<pre>
6419 declare void @llvm.trap()
6420</pre>
6421
6422<h5>Overview:</h5>
6423
6424<p>
6425The '<tt>llvm.trap</tt>' intrinsic
6426</p>
6427
6428<h5>Arguments:</h5>
6429
6430<p>
6431None
6432</p>
6433
6434<h5>Semantics:</h5>
6435
6436<p>
6437This intrinsics is lowered to the target dependent trap instruction. If the
6438target does not have a trap instruction, this intrinsic will be lowered to the
6439call of the abort() function.
6440</p>
6441</div>
6442
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6443<!-- _______________________________________________________________________ -->
6444<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6445 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6446</div>
6447<div class="doc_text">
6448<h5>Syntax:</h5>
6449<pre>
6450declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6451
6452</pre>
6453<h5>Overview:</h5>
6454<p>
6455 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6456 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6457 it is placed on the stack before local variables.
6458</p>
6459<h5>Arguments:</h5>
6460<p>
6461 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6462 first argument is the value loaded from the stack guard
6463 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6464 has enough space to hold the value of the guard.
6465</p>
6466<h5>Semantics:</h5>
6467<p>
6468 This intrinsic causes the prologue/epilogue inserter to force the position of
6469 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6470 stack. This is to ensure that if a local variable on the stack is overwritten,
6471 it will destroy the value of the guard. When the function exits, the guard on
6472 the stack is checked against the original guard. If they're different, then
6473 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6474</p>
6475</div>
6476
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6477<!-- *********************************************************************** -->
6478<hr>
6479<address>
6480 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
6481 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6482 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6483 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6484
6485 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6486 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6487 Last modified: $Date$
6488</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6490</body>
6491</html>