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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
Dan Gohman4dfac702008-11-24 17:18:39 +0000[diff] [blame]568<p>For example, since the "<tt>.LC0</tt>"
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]569variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
570variable and was linked with this one, one of the two would be renamed,
571preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
572external (i.e., lacking any linkage declarations), they are accessible
573outside of the current module.</p>
574<p>It is illegal for a function <i>declaration</i>
575to have any linkage type other than "externally visible", <tt>dllimport</tt>,
576or <tt>extern_weak</tt>.</p>
577<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]578linkages.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]579</div>
580
581<!-- ======================================================================= -->
582<div class="doc_subsection">
583 <a name="callingconv">Calling Conventions</a>
584</div>
585
586<div class="doc_text">
587
588<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
589and <a href="#i_invoke">invokes</a> can all have an optional calling convention
590specified for the call. The calling convention of any pair of dynamic
591caller/callee must match, or the behavior of the program is undefined. The
592following calling conventions are supported by LLVM, and more may be added in
593the future:</p>
594
595<dl>
596 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
597
598 <dd>This calling convention (the default if no other calling convention is
599 specified) matches the target C calling conventions. This calling convention
600 supports varargs function calls and tolerates some mismatch in the declared
601 prototype and implemented declaration of the function (as does normal C).
602 </dd>
603
604 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
605
606 <dd>This calling convention attempts to make calls as fast as possible
607 (e.g. by passing things in registers). This calling convention allows the
608 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]609 without having to conform to an externally specified ABI (Application Binary
610 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer07444922008-05-14 09:17:12 +0000[diff] [blame]611 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
612 supported. This calling convention does not support varargs and requires the
613 prototype of all callees to exactly match the prototype of the function
614 definition.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]615 </dd>
616
617 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
618
619 <dd>This calling convention attempts to make code in the caller as efficient
620 as possible under the assumption that the call is not commonly executed. As
621 such, these calls often preserve all registers so that the call does not break
622 any live ranges in the caller side. This calling convention does not support
623 varargs and requires the prototype of all callees to exactly match the
624 prototype of the function definition.
625 </dd>
626
627 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
628
629 <dd>Any calling convention may be specified by number, allowing
630 target-specific calling conventions to be used. Target specific calling
631 conventions start at 64.
632 </dd>
633</dl>
634
635<p>More calling conventions can be added/defined on an as-needed basis, to
636support pascal conventions or any other well-known target-independent
637convention.</p>
638
639</div>
640
641<!-- ======================================================================= -->
642<div class="doc_subsection">
643 <a name="visibility">Visibility Styles</a>
644</div>
645
646<div class="doc_text">
647
648<p>
649All Global Variables and Functions have one of the following visibility styles:
650</p>
651
652<dl>
653 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
654
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]655 <dd>On targets that use the ELF object file format, default visibility means
656 that the declaration is visible to other
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]657 modules and, in shared libraries, means that the declared entity may be
658 overridden. On Darwin, default visibility means that the declaration is
659 visible to other modules. Default visibility corresponds to "external
660 linkage" in the language.
661 </dd>
662
663 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
664
665 <dd>Two declarations of an object with hidden visibility refer to the same
666 object if they are in the same shared object. Usually, hidden visibility
667 indicates that the symbol will not be placed into the dynamic symbol table,
668 so no other module (executable or shared library) can reference it
669 directly.
670 </dd>
671
672 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
673
674 <dd>On ELF, protected visibility indicates that the symbol will be placed in
675 the dynamic symbol table, but that references within the defining module will
676 bind to the local symbol. That is, the symbol cannot be overridden by another
677 module.
678 </dd>
679</dl>
680
681</div>
682
683<!-- ======================================================================= -->
684<div class="doc_subsection">
685 <a name="globalvars">Global Variables</a>
686</div>
687
688<div class="doc_text">
689
690<p>Global variables define regions of memory allocated at compilation time
691instead of run-time. Global variables may optionally be initialized, may have
692an explicit section to be placed in, and may have an optional explicit alignment
693specified. A variable may be defined as "thread_local", which means that it
694will not be shared by threads (each thread will have a separated copy of the
695variable). A variable may be defined as a global "constant," which indicates
696that the contents of the variable will <b>never</b> be modified (enabling better
697optimization, allowing the global data to be placed in the read-only section of
698an executable, etc). Note that variables that need runtime initialization
699cannot be marked "constant" as there is a store to the variable.</p>
700
701<p>
702LLVM explicitly allows <em>declarations</em> of global variables to be marked
703constant, even if the final definition of the global is not. This capability
704can be used to enable slightly better optimization of the program, but requires
705the language definition to guarantee that optimizations based on the
706'constantness' are valid for the translation units that do not include the
707definition.
708</p>
709
710<p>As SSA values, global variables define pointer values that are in
711scope (i.e. they dominate) all basic blocks in the program. Global
712variables always define a pointer to their "content" type because they
713describe a region of memory, and all memory objects in LLVM are
714accessed through pointers.</p>
715
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]716<p>A global variable may be declared to reside in a target-specifc numbered
717address space. For targets that support them, address spaces may affect how
718optimizations are performed and/or what target instructions are used to access
Christopher Lamb20a39e92007-12-12 08:44:39 +0000[diff] [blame]719the variable. The default address space is zero. The address space qualifier
720must precede any other attributes.</p>
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]721
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]722<p>LLVM allows an explicit section to be specified for globals. If the target
723supports it, it will emit globals to the section specified.</p>
724
725<p>An explicit alignment may be specified for a global. If not present, or if
726the alignment is set to zero, the alignment of the global is set by the target
727to whatever it feels convenient. If an explicit alignment is specified, the
728global is forced to have at least that much alignment. All alignments must be
729a power of 2.</p>
730
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]731<p>For example, the following defines a global in a numbered address space with
732an initializer, section, and alignment:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]733
734<div class="doc_code">
735<pre>
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
Edwin Török76433cc2008-11-24 08:02:24 +0000[diff] [blame]897 caller. Note that this applies only to pointers that can be used to actually
898 load/store a value: NULL, unique pointers from malloc(0), and freed pointers
899 are considered to not alias anything.</dd>
Chris Lattner275e6be2008-01-11 06:20:47 +0000[diff] [blame]900
Duncan Sands4ee46812007-07-27 19:57:41 +0000[diff] [blame]901 <dt><tt>nest</tt></dt>
Duncan Sandsf1a7d4c2008-07-08 09:27:25 +0000[diff] [blame]902 <dd>This indicates that the pointer parameter can be excised using the
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]903 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
904 attribute for return values.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]905 </dl>
906
907</div>
908
909<!-- ======================================================================= -->
910<div class="doc_subsection">
Gordon Henriksen13fe5e32007-12-10 03:18:06 +0000[diff] [blame]911 <a name="gc">Garbage Collector Names</a>
912</div>
913
914<div class="doc_text">
915<p>Each function may specify a garbage collector name, which is simply a
916string.</p>
917
918<div class="doc_code"><pre
919>define void @f() gc "name" { ...</pre></div>
920
921<p>The compiler declares the supported values of <i>name</i>. Specifying a
922collector which will cause the compiler to alter its output in order to support
923the named garbage collection algorithm.</p>
924</div>
925
926<!-- ======================================================================= -->
927<div class="doc_subsection">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]928 <a name="fnattrs">Function Attributes</a>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]929</div>
930
931<div class="doc_text">
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]932
933<p>Function attributes are set to communicate additional information about
934 a function. Function attributes are considered to be part of the function,
935 not of the function type, so functions with different parameter attributes
936 can have the same function type.</p>
937
938 <p>Function attributes are simple keywords that follow the type specified. If
939 multiple attributes are needed, they are space separated. For
940 example:</p>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]941
942<div class="doc_code">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]943<pre>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]944define void @f() noinline { ... }
945define void @f() alwaysinline { ... }
946define void @f() alwaysinline optsize { ... }
947define void @f() optsize
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]948</pre>
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]949</div>
950
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]951<dl>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]952<dt><tt>alwaysinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]953<dd>This attribute indicates that the inliner should attempt to inline this
954function into callers whenever possible, ignoring any active inlining size
955threshold for this caller.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]956
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]957<dt><tt>noinline</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]958<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner377f3ae2008-10-05 17:14:59 +0000[diff] [blame]959in any situation. This attribute may not be used together with the
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]960<tt>alwaysinline</tt> attribute.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]961
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]962<dt><tt>optsize</tt></dt>
Devang Patelc29099b2008-09-29 18:34:44 +0000[diff] [blame]963<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]964make choices that keep the code size of this function low, and otherwise do
965optimizations specifically to reduce code size.</dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]966
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]967<dt><tt>noreturn</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]968<dd>This function attribute indicates that the function never returns normally.
969This produces undefined behavior at runtime if the function ever does
970dynamically return.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]971
972<dt><tt>nounwind</tt></dt>
Chris Lattner82d70f92008-10-04 18:23:17 +0000[diff] [blame]973<dd>This function attribute indicates that the function never returns with an
974unwind or exceptional control flow. If the function does unwind, its runtime
975behavior is undefined.</dd>
976
977<dt><tt>readnone</tt></dt>
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]978<dd>This attribute indicates that the function computes its result (or the
979exception it throws) based strictly on its arguments, without dereferencing any
980pointer arguments or otherwise accessing any mutable state (e.g. memory, control
981registers, etc) visible to caller functions. It does not write through any
982pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
983never changes any state visible to callers.</dd>
Devang Patel008cd3e2008-09-26 23:51:19 +0000[diff] [blame]984
Duncan Sands7d94e5a2008-10-06 08:14:18 +0000[diff] [blame]985<dt><tt><a name="readonly">readonly</a></tt></dt>
986<dd>This attribute indicates that the function does not write through any
987pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
988or otherwise modify any state (e.g. memory, control registers, etc) visible to
989caller functions. It may dereference pointer arguments and read state that may
990be set in the caller. A readonly function always returns the same value (or
991throws the same exception) when called with the same set of arguments and global
992state.</dd>
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]993
994<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]995<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]996protector. It is in the form of a "canary"&mdash;a random value placed on the
997stack before the local variables that's checked upon return from the function to
998see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]999needs stack protectors or not.
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1000
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1001<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1002that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1003have an <tt>ssp</tt> attribute.</p></dd>
1004
1005<dt><tt>sspreq</tt></dt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1006<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlingdfaabba2008-11-13 01:02:51 +0000[diff] [blame]1007stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling34f70d82008-11-26 19:19:05 +0000[diff] [blame]1008function attribute.
Bill Wendlingbe9ec3f2008-11-26 19:07:40 +0000[diff] [blame]1009
1010<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1011function that doesn't have an <tt>sspreq</tt> attribute or which has
1012an <tt>ssp</tt> attribute, then the resulting function will have
1013an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1014</dl>
1015
Devang Pateld468f1c2008-09-04 23:05:13 +0000[diff] [blame]1016</div>
1017
1018<!-- ======================================================================= -->
1019<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1020 <a name="moduleasm">Module-Level Inline Assembly</a>
1021</div>
1022
1023<div class="doc_text">
1024<p>
1025Modules may contain "module-level inline asm" blocks, which corresponds to the
1026GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1027LLVM and treated as a single unit, but may be separated in the .ll file if
1028desired. The syntax is very simple:
1029</p>
1030
1031<div class="doc_code">
1032<pre>
1033module asm "inline asm code goes here"
1034module asm "more can go here"
1035</pre>
1036</div>
1037
1038<p>The strings can contain any character by escaping non-printable characters.
1039 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1040 for the number.
1041</p>
1042
1043<p>
1044 The inline asm code is simply printed to the machine code .s file when
1045 assembly code is generated.
1046</p>
1047</div>
1048
1049<!-- ======================================================================= -->
1050<div class="doc_subsection">
1051 <a name="datalayout">Data Layout</a>
1052</div>
1053
1054<div class="doc_text">
1055<p>A module may specify a target specific data layout string that specifies how
1056data is to be laid out in memory. The syntax for the data layout is simply:</p>
1057<pre> target datalayout = "<i>layout specification</i>"</pre>
1058<p>The <i>layout specification</i> consists of a list of specifications
1059separated by the minus sign character ('-'). Each specification starts with a
1060letter and may include other information after the letter to define some
1061aspect of the data layout. The specifications accepted are as follows: </p>
1062<dl>
1063 <dt><tt>E</tt></dt>
1064 <dd>Specifies that the target lays out data in big-endian form. That is, the
1065 bits with the most significance have the lowest address location.</dd>
1066 <dt><tt>e</tt></dt>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1067 <dd>Specifies that the target lays out data in little-endian form. That is,
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1068 the bits with the least significance have the lowest address location.</dd>
1069 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1070 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1071 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1072 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1073 too.</dd>
1074 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1075 <dd>This specifies the alignment for an integer type of a given bit
1076 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1077 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1078 <dd>This specifies the alignment for a vector type of a given bit
1079 <i>size</i>.</dd>
1080 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1081 <dd>This specifies the alignment for a floating point type of a given bit
1082 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1083 (double).</dd>
1084 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1085 <dd>This specifies the alignment for an aggregate type of a given bit
1086 <i>size</i>.</dd>
1087</dl>
1088<p>When constructing the data layout for a given target, LLVM starts with a
1089default set of specifications which are then (possibly) overriden by the
1090specifications in the <tt>datalayout</tt> keyword. The default specifications
1091are given in this list:</p>
1092<ul>
1093 <li><tt>E</tt> - big endian</li>
1094 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1095 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1096 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1097 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1098 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1099 <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]1100 alignment of 64-bits</li>
1101 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1102 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1103 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1104 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1105 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1106</ul>
Chris Lattner6a9f3c42008-08-05 18:21:08 +0000[diff] [blame]1107<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1108following rules:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1109<ol>
1110 <li>If the type sought is an exact match for one of the specifications, that
1111 specification is used.</li>
1112 <li>If no match is found, and the type sought is an integer type, then the
1113 smallest integer type that is larger than the bitwidth of the sought type is
1114 used. If none of the specifications are larger than the bitwidth then the the
1115 largest integer type is used. For example, given the default specifications
1116 above, the i7 type will use the alignment of i8 (next largest) while both
1117 i65 and i256 will use the alignment of i64 (largest specified).</li>
1118 <li>If no match is found, and the type sought is a vector type, then the
1119 largest vector type that is smaller than the sought vector type will be used
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1120 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1121 in terms of 64 &lt;2 x double&gt;, for example.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1122</ol>
1123</div>
1124
1125<!-- *********************************************************************** -->
1126<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1127<!-- *********************************************************************** -->
1128
1129<div class="doc_text">
1130
1131<p>The LLVM type system is one of the most important features of the
1132intermediate representation. Being typed enables a number of
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]1133optimizations to be performed on the intermediate representation directly,
1134without having to do
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1135extra analyses on the side before the transformation. A strong type
1136system makes it easier to read the generated code and enables novel
1137analyses and transformations that are not feasible to perform on normal
1138three address code representations.</p>
1139
1140</div>
1141
1142<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1143<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1144Classifications</a> </div>
1145<div class="doc_text">
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1146<p>The types fall into a few useful
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1147classifications:</p>
1148
1149<table border="1" cellspacing="0" cellpadding="4">
1150 <tbody>
1151 <tr><th>Classification</th><th>Types</th></tr>
1152 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1153 <td><a href="#t_integer">integer</a></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1154 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
1155 </tr>
1156 <tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1157 <td><a href="#t_floating">floating point</a></td>
1158 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1159 </tr>
1160 <tr>
1161 <td><a name="t_firstclass">first class</a></td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1162 <td><a href="#t_integer">integer</a>,
1163 <a href="#t_floating">floating point</a>,
1164 <a href="#t_pointer">pointer</a>,
Dan Gohmanf6237db2008-06-18 18:42:13 +0000[diff] [blame]1165 <a href="#t_vector">vector</a>,
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]1166 <a href="#t_struct">structure</a>,
1167 <a href="#t_array">array</a>,
Dan Gohmand13951e2008-05-23 22:50:26 +0000[diff] [blame]1168 <a href="#t_label">label</a>.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1169 </td>
1170 </tr>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1171 <tr>
1172 <td><a href="#t_primitive">primitive</a></td>
1173 <td><a href="#t_label">label</a>,
1174 <a href="#t_void">void</a>,
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1175 <a href="#t_floating">floating point</a>.</td>
1176 </tr>
1177 <tr>
1178 <td><a href="#t_derived">derived</a></td>
1179 <td><a href="#t_integer">integer</a>,
1180 <a href="#t_array">array</a>,
1181 <a href="#t_function">function</a>,
1182 <a href="#t_pointer">pointer</a>,
1183 <a href="#t_struct">structure</a>,
1184 <a href="#t_pstruct">packed structure</a>,
1185 <a href="#t_vector">vector</a>,
1186 <a href="#t_opaque">opaque</a>.
Dan Gohman032ba852008-10-14 16:32:04 +0000[diff] [blame]1187 </td>
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1188 </tr>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1189 </tbody>
1190</table>
1191
1192<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1193most important. Values of these types are the only ones which can be
1194produced by instructions, passed as arguments, or used as operands to
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]1195instructions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1196</div>
1197
1198<!-- ======================================================================= -->
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1199<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1200
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1201<div class="doc_text">
1202<p>The primitive types are the fundamental building blocks of the LLVM
1203system.</p>
1204
Chris Lattner86437612008-01-04 04:34:14 +0000[diff] [blame]1205</div>
1206
Chris Lattner488772f2008-01-04 04:32:38 +0000[diff] [blame]1207<!-- _______________________________________________________________________ -->
1208<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1209
1210<div class="doc_text">
1211 <table>
1212 <tbody>
1213 <tr><th>Type</th><th>Description</th></tr>
1214 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1215 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1216 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1217 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1218 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1219 </tbody>
1220 </table>
1221</div>
1222
1223<!-- _______________________________________________________________________ -->
1224<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1225
1226<div class="doc_text">
1227<h5>Overview:</h5>
1228<p>The void type does not represent any value and has no size.</p>
1229
1230<h5>Syntax:</h5>
1231
1232<pre>
1233 void
1234</pre>
1235</div>
1236
1237<!-- _______________________________________________________________________ -->
1238<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1239
1240<div class="doc_text">
1241<h5>Overview:</h5>
1242<p>The label type represents code labels.</p>
1243
1244<h5>Syntax:</h5>
1245
1246<pre>
1247 label
1248</pre>
1249</div>
1250
1251
1252<!-- ======================================================================= -->
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1253<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
1254
1255<div class="doc_text">
1256
1257<p>The real power in LLVM comes from the derived types in the system.
1258This is what allows a programmer to represent arrays, functions,
1259pointers, and other useful types. Note that these derived types may be
1260recursive: For example, it is possible to have a two dimensional array.</p>
1261
1262</div>
1263
1264<!-- _______________________________________________________________________ -->
1265<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1266
1267<div class="doc_text">
1268
1269<h5>Overview:</h5>
1270<p>The integer type is a very simple derived type that simply specifies an
1271arbitrary bit width for the integer type desired. Any bit width from 1 bit to
12722^23-1 (about 8 million) can be specified.</p>
1273
1274<h5>Syntax:</h5>
1275
1276<pre>
1277 iN
1278</pre>
1279
1280<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1281value.</p>
1282
1283<h5>Examples:</h5>
1284<table class="layout">
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1285 <tbody>
1286 <tr>
1287 <td><tt>i1</tt></td>
1288 <td>a single-bit integer.</td>
1289 </tr><tr>
1290 <td><tt>i32</tt></td>
1291 <td>a 32-bit integer.</td>
1292 </tr><tr>
1293 <td><tt>i1942652</tt></td>
1294 <td>a really big integer of over 1 million bits.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1295 </tr>
Chris Lattner251ab812007-12-18 06:18:21 +0000[diff] [blame]1296 </tbody>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1297</table>
1298</div>
1299
1300<!-- _______________________________________________________________________ -->
1301<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
1302
1303<div class="doc_text">
1304
1305<h5>Overview:</h5>
1306
1307<p>The array type is a very simple derived type that arranges elements
1308sequentially in memory. The array type requires a size (number of
1309elements) and an underlying data type.</p>
1310
1311<h5>Syntax:</h5>
1312
1313<pre>
1314 [&lt;# elements&gt; x &lt;elementtype&gt;]
1315</pre>
1316
1317<p>The number of elements is a constant integer value; elementtype may
1318be any type with a size.</p>
1319
1320<h5>Examples:</h5>
1321<table class="layout">
1322 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1323 <td class="left"><tt>[40 x i32]</tt></td>
1324 <td class="left">Array of 40 32-bit integer values.</td>
1325 </tr>
1326 <tr class="layout">
1327 <td class="left"><tt>[41 x i32]</tt></td>
1328 <td class="left">Array of 41 32-bit integer values.</td>
1329 </tr>
1330 <tr class="layout">
1331 <td class="left"><tt>[4 x i8]</tt></td>
1332 <td class="left">Array of 4 8-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1333 </tr>
1334</table>
1335<p>Here are some examples of multidimensional arrays:</p>
1336<table class="layout">
1337 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1338 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1339 <td class="left">3x4 array of 32-bit integer values.</td>
1340 </tr>
1341 <tr class="layout">
1342 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1343 <td class="left">12x10 array of single precision floating point values.</td>
1344 </tr>
1345 <tr class="layout">
1346 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1347 <td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1348 </tr>
1349</table>
1350
1351<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1352length array. Normally, accesses past the end of an array are undefined in
1353LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1354As a special case, however, zero length arrays are recognized to be variable
1355length. This allows implementation of 'pascal style arrays' with the LLVM
1356type "{ i32, [0 x float]}", for example.</p>
1357
1358</div>
1359
1360<!-- _______________________________________________________________________ -->
1361<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
1362<div class="doc_text">
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1363
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1364<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1365
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1366<p>The function type can be thought of as a function signature. It
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1367consists of a return type and a list of formal parameter types. The
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1368return 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]1369If 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]1370class types, and the struct must have at least one element.</p>
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1371
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1372<h5>Syntax:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1373
1374<pre>
1375 &lt;returntype list&gt; (&lt;parameter list&gt;)
1376</pre>
1377
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1378<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
1379specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
1380which indicates that the function takes a variable number of arguments.
1381Variable argument functions can access their arguments with the <a
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]1382 href="#int_varargs">variable argument handling intrinsic</a> functions.
1383'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1384<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1385
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1386<h5>Examples:</h5>
1387<table class="layout">
1388 <tr class="layout">
1389 <td class="left"><tt>i32 (i32)</tt></td>
1390 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
1391 </td>
1392 </tr><tr class="layout">
Reid Spencerf234bed2007-07-19 23:13:04 +0000[diff] [blame]1393 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1394 </tt></td>
1395 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1396 an <tt>i16</tt> that should be sign extended and a
1397 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
1398 <tt>float</tt>.
1399 </td>
1400 </tr><tr class="layout">
1401 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1402 <td class="left">A vararg function that takes at least one
1403 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
1404 which returns an integer. This is the signature for <tt>printf</tt> in
1405 LLVM.
1406 </td>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1407 </tr><tr class="layout">
1408 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanafc88b02008-11-27 06:41:20 +0000[diff] [blame]1409 <td class="left">A function taking an <tt>i32</tt>, returning two
1410 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Pateld4ba41d2008-03-24 05:35:41 +0000[diff] [blame]1411 </td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1412 </tr>
1413</table>
1414
1415</div>
1416<!-- _______________________________________________________________________ -->
1417<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
1418<div class="doc_text">
1419<h5>Overview:</h5>
1420<p>The structure type is used to represent a collection of data members
1421together in memory. The packing of the field types is defined to match
1422the ABI of the underlying processor. The elements of a structure may
1423be any type that has a size.</p>
1424<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1425and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1426field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1427instruction.</p>
1428<h5>Syntax:</h5>
1429<pre> { &lt;type list&gt; }<br></pre>
1430<h5>Examples:</h5>
1431<table class="layout">
1432 <tr class="layout">
1433 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1434 <td class="left">A triple of three <tt>i32</tt> values</td>
1435 </tr><tr class="layout">
1436 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1437 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1438 second element is a <a href="#t_pointer">pointer</a> to a
1439 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1440 an <tt>i32</tt>.</td>
1441 </tr>
1442</table>
1443</div>
1444
1445<!-- _______________________________________________________________________ -->
1446<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1447</div>
1448<div class="doc_text">
1449<h5>Overview:</h5>
1450<p>The packed structure type is used to represent a collection of data members
1451together in memory. There is no padding between fields. Further, the alignment
1452of a packed structure is 1 byte. The elements of a packed structure may
1453be any type that has a size.</p>
1454<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1455and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1456field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1457instruction.</p>
1458<h5>Syntax:</h5>
1459<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1460<h5>Examples:</h5>
1461<table class="layout">
1462 <tr class="layout">
1463 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1464 <td class="left">A triple of three <tt>i32</tt> values</td>
1465 </tr><tr class="layout">
Bill Wendling74d3eac2008-09-07 10:26:33 +0000[diff] [blame]1466 <td class="left">
1467<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1468 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1469 second element is a <a href="#t_pointer">pointer</a> to a
1470 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1471 an <tt>i32</tt>.</td>
1472 </tr>
1473</table>
1474</div>
1475
1476<!-- _______________________________________________________________________ -->
1477<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
1478<div class="doc_text">
1479<h5>Overview:</h5>
1480<p>As in many languages, the pointer type represents a pointer or
Christopher Lambdd0049d2007-12-11 09:31:00 +0000[diff] [blame]1481reference to another object, which must live in memory. Pointer types may have
1482an optional address space attribute defining the target-specific numbered
1483address space where the pointed-to object resides. The default address space is
1484zero.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1485<h5>Syntax:</h5>
1486<pre> &lt;type&gt; *<br></pre>
1487<h5>Examples:</h5>
1488<table class="layout">
1489 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1490 <td class="left"><tt>[4x i32]*</tt></td>
1491 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1492 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1493 </tr>
1494 <tr class="layout">
1495 <td class="left"><tt>i32 (i32 *) *</tt></td>
1496 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1497 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1498 <tt>i32</tt>.</td>
1499 </tr>
1500 <tr class="layout">
1501 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1502 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1503 that resides in address space #5.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1504 </tr>
1505</table>
1506</div>
1507
1508<!-- _______________________________________________________________________ -->
1509<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
1510<div class="doc_text">
1511
1512<h5>Overview:</h5>
1513
1514<p>A vector type is a simple derived type that represents a vector
1515of elements. Vector types are used when multiple primitive data
1516are operated in parallel using a single instruction (SIMD).
1517A vector type requires a size (number of
1518elements) and an underlying primitive data type. Vectors must have a power
1519of two length (1, 2, 4, 8, 16 ...). Vector types are
1520considered <a href="#t_firstclass">first class</a>.</p>
1521
1522<h5>Syntax:</h5>
1523
1524<pre>
1525 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1526</pre>
1527
1528<p>The number of elements is a constant integer value; elementtype may
1529be any integer or floating point type.</p>
1530
1531<h5>Examples:</h5>
1532
1533<table class="layout">
1534 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1535 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1536 <td class="left">Vector of 4 32-bit integer values.</td>
1537 </tr>
1538 <tr class="layout">
1539 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1540 <td class="left">Vector of 8 32-bit floating-point values.</td>
1541 </tr>
1542 <tr class="layout">
1543 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1544 <td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1545 </tr>
1546</table>
1547</div>
1548
1549<!-- _______________________________________________________________________ -->
1550<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1551<div class="doc_text">
1552
1553<h5>Overview:</h5>
1554
1555<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksenda0706e2007-10-14 00:34:53 +0000[diff] [blame]1556corresponds (for example) to the C notion of a forward declared structure type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1557In LLVM, opaque types can eventually be resolved to any type (not just a
1558structure type).</p>
1559
1560<h5>Syntax:</h5>
1561
1562<pre>
1563 opaque
1564</pre>
1565
1566<h5>Examples:</h5>
1567
1568<table class="layout">
1569 <tr class="layout">
Chris Lattner7311d222007-12-19 05:04:11 +0000[diff] [blame]1570 <td class="left"><tt>opaque</tt></td>
1571 <td class="left">An opaque type.</td>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1572 </tr>
1573</table>
1574</div>
1575
1576
1577<!-- *********************************************************************** -->
1578<div class="doc_section"> <a name="constants">Constants</a> </div>
1579<!-- *********************************************************************** -->
1580
1581<div class="doc_text">
1582
1583<p>LLVM has several different basic types of constants. This section describes
1584them all and their syntax.</p>
1585
1586</div>
1587
1588<!-- ======================================================================= -->
1589<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
1590
1591<div class="doc_text">
1592
1593<dl>
1594 <dt><b>Boolean constants</b></dt>
1595
1596 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1597 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
1598 </dd>
1599
1600 <dt><b>Integer constants</b></dt>
1601
1602 <dd>Standard integers (such as '4') are constants of the <a
1603 href="#t_integer">integer</a> type. Negative numbers may be used with
1604 integer types.
1605 </dd>
1606
1607 <dt><b>Floating point constants</b></dt>
1608
1609 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1610 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]1611 notation (see below). The assembler requires the exact decimal value of
1612 a floating-point constant. For example, the assembler accepts 1.25 but
1613 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1614 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1615
1616 <dt><b>Null pointer constants</b></dt>
1617
1618 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
1619 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1620
1621</dl>
1622
1623<p>The one non-intuitive notation for constants is the optional hexadecimal form
1624of floating point constants. For example, the form '<tt>double
16250x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
16264.5e+15</tt>'. The only time hexadecimal floating point constants are required
1627(and the only time that they are generated by the disassembler) is when a
1628floating point constant must be emitted but it cannot be represented as a
1629decimal floating point number. For example, NaN's, infinities, and other
1630special values are represented in their IEEE hexadecimal format so that
1631assembly and disassembly do not cause any bits to change in the constants.</p>
1632
1633</div>
1634
1635<!-- ======================================================================= -->
1636<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1637</div>
1638
1639<div class="doc_text">
1640<p>Aggregate constants arise from aggregation of simple constants
1641and smaller aggregate constants.</p>
1642
1643<dl>
1644 <dt><b>Structure constants</b></dt>
1645
1646 <dd>Structure constants are represented with notation similar to structure
1647 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattner6c8de962007-12-25 20:34:52 +0000[diff] [blame]1648 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1649 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]1650 must have <a href="#t_struct">structure type</a>, and the number and
1651 types of elements must match those specified by the type.
1652 </dd>
1653
1654 <dt><b>Array constants</b></dt>
1655
1656 <dd>Array constants are represented with notation similar to array type
1657 definitions (a comma separated list of elements, surrounded by square brackets
1658 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
1659 constants must have <a href="#t_array">array type</a>, and the number and
1660 types of elements must match those specified by the type.
1661 </dd>
1662
1663 <dt><b>Vector constants</b></dt>
1664
1665 <dd>Vector constants are represented with notation similar to vector type
1666 definitions (a comma separated list of elements, surrounded by
1667 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1668 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
1669 href="#t_vector">vector type</a>, and the number and types of elements must
1670 match those specified by the type.
1671 </dd>
1672
1673 <dt><b>Zero initialization</b></dt>
1674
1675 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1676 value to zero of <em>any</em> type, including scalar and aggregate types.
1677 This is often used to avoid having to print large zero initializers (e.g. for
1678 large arrays) and is always exactly equivalent to using explicit zero
1679 initializers.
1680 </dd>
1681</dl>
1682
1683</div>
1684
1685<!-- ======================================================================= -->
1686<div class="doc_subsection">
1687 <a name="globalconstants">Global Variable and Function Addresses</a>
1688</div>
1689
1690<div class="doc_text">
1691
1692<p>The addresses of <a href="#globalvars">global variables</a> and <a
1693href="#functionstructure">functions</a> are always implicitly valid (link-time)
1694constants. These constants are explicitly referenced when the <a
1695href="#identifiers">identifier for the global</a> is used and always have <a
1696href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1697file:</p>
1698
1699<div class="doc_code">
1700<pre>
1701@X = global i32 17
1702@Y = global i32 42
1703@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
1704</pre>
1705</div>
1706
1707</div>
1708
1709<!-- ======================================================================= -->
1710<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
1711<div class="doc_text">
1712 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1713 no specific value. Undefined values may be of any type and be used anywhere
1714 a constant is permitted.</p>
1715
1716 <p>Undefined values indicate to the compiler that the program is well defined
1717 no matter what value is used, giving the compiler more freedom to optimize.
1718 </p>
1719</div>
1720
1721<!-- ======================================================================= -->
1722<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1723</div>
1724
1725<div class="doc_text">
1726
1727<p>Constant expressions are used to allow expressions involving other constants
1728to be used as constants. Constant expressions may be of any <a
1729href="#t_firstclass">first class</a> type and may involve any LLVM operation
1730that does not have side effects (e.g. load and call are not supported). The
1731following is the syntax for constant expressions:</p>
1732
1733<dl>
1734 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1735 <dd>Truncate a constant to another type. The bit size of CST must be larger
1736 than the bit size of TYPE. Both types must be integers.</dd>
1737
1738 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1739 <dd>Zero extend a constant to another type. The bit size of CST must be
1740 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1741
1742 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1743 <dd>Sign extend a constant to another type. The bit size of CST must be
1744 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
1745
1746 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1747 <dd>Truncate a floating point constant to another floating point type. The
1748 size of CST must be larger than the size of TYPE. Both types must be
1749 floating point.</dd>
1750
1751 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1752 <dd>Floating point extend a constant to another type. The size of CST must be
1753 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1754
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]1755 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1756 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1757 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1758 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1759 of the same number of elements. If the value won't fit in the integer type,
1760 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1761
1762 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
1763 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1764 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1765 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1766 of the same number of elements. If the value won't fit in the integer type,
1767 the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1768
1769 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
1770 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1771 constant. TYPE must be a scalar or vector floating point type. CST must be of
1772 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1773 of the same number of elements. If the value won't fit in the floating point
1774 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1775
1776 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
1777 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]1778 constant. TYPE must be a scalar or vector floating point type. CST must be of
1779 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1780 of the same number of elements. If the value won't fit in the floating point
1781 type, the results are undefined.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1782
1783 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1784 <dd>Convert a pointer typed constant to the corresponding integer constant
1785 TYPE must be an integer type. CST must be of pointer type. The CST value is
1786 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1787
1788 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1789 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1790 pointer type. CST must be of integer type. The CST value is zero extended,
1791 truncated, or unchanged to make it fit in a pointer size. This one is
1792 <i>really</i> dangerous!</dd>
1793
1794 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
1795 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1796 identical (same number of bits). The conversion is done as if the CST value
1797 was stored to memory and read back as TYPE. In other words, no bits change
1798 with this operator, just the type. This can be used for conversion of
1799 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]1800 pointers it is only valid to cast to another pointer type. It is not valid
1801 to bitcast to or from an aggregate type.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1802 </dd>
1803
1804 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1805
1806 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1807 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1808 instruction, the index list may have zero or more indexes, which are required
1809 to make sense for the type of "CSTPTR".</dd>
1810
1811 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1812
1813 <dd>Perform the <a href="#i_select">select operation</a> on
1814 constants.</dd>
1815
1816 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1817 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1818
1819 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1820 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
1821
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]1822 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
1823 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
1824
1825 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
1826 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
1827
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1828 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1829
1830 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1831 operation</a> on constants.</dd>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1832
1833 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1834
1835 <dd>Perform the <a href="#i_insertelement">insertelement
1836 operation</a> on constants.</dd>
1837
1838
1839 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1840
1841 <dd>Perform the <a href="#i_shufflevector">shufflevector
1842 operation</a> on constants.</dd>
1843
1844 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1845
1846 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1847 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
1848 binary</a> operations. The constraints on operands are the same as those for
1849 the corresponding instruction (e.g. no bitwise operations on floating point
1850 values are allowed).</dd>
1851</dl>
1852</div>
1853
1854<!-- *********************************************************************** -->
1855<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1856<!-- *********************************************************************** -->
1857
1858<!-- ======================================================================= -->
1859<div class="doc_subsection">
1860<a name="inlineasm">Inline Assembler Expressions</a>
1861</div>
1862
1863<div class="doc_text">
1864
1865<p>
1866LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1867Module-Level Inline Assembly</a>) through the use of a special value. This
1868value represents the inline assembler as a string (containing the instructions
1869to emit), a list of operand constraints (stored as a string), and a flag that
1870indicates whether or not the inline asm expression has side effects. An example
1871inline assembler expression is:
1872</p>
1873
1874<div class="doc_code">
1875<pre>
1876i32 (i32) asm "bswap $0", "=r,r"
1877</pre>
1878</div>
1879
1880<p>
1881Inline assembler expressions may <b>only</b> be used as the callee operand of
1882a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1883</p>
1884
1885<div class="doc_code">
1886<pre>
1887%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
1888</pre>
1889</div>
1890
1891<p>
1892Inline asms with side effects not visible in the constraint list must be marked
1893as having side effects. This is done through the use of the
1894'<tt>sideeffect</tt>' keyword, like so:
1895</p>
1896
1897<div class="doc_code">
1898<pre>
1899call void asm sideeffect "eieio", ""()
1900</pre>
1901</div>
1902
1903<p>TODO: The format of the asm and constraints string still need to be
1904documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattner1cdd64e2008-10-04 18:36:02 +0000[diff] [blame]1905need to be documented). This is probably best done by reference to another
1906document that covers inline asm from a holistic perspective.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1907</p>
1908
1909</div>
1910
1911<!-- *********************************************************************** -->
1912<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1913<!-- *********************************************************************** -->
1914
1915<div class="doc_text">
1916
1917<p>The LLVM instruction set consists of several different
1918classifications of instructions: <a href="#terminators">terminator
1919instructions</a>, <a href="#binaryops">binary instructions</a>,
1920<a href="#bitwiseops">bitwise binary instructions</a>, <a
1921 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1922instructions</a>.</p>
1923
1924</div>
1925
1926<!-- ======================================================================= -->
1927<div class="doc_subsection"> <a name="terminators">Terminator
1928Instructions</a> </div>
1929
1930<div class="doc_text">
1931
1932<p>As mentioned <a href="#functionstructure">previously</a>, every
1933basic block in a program ends with a "Terminator" instruction, which
1934indicates which block should be executed after the current block is
1935finished. These terminator instructions typically yield a '<tt>void</tt>'
1936value: they produce control flow, not values (the one exception being
1937the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
1938<p>There are six different terminator instructions: the '<a
1939 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1940instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
1941the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1942 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1943 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
1944
1945</div>
1946
1947<!-- _______________________________________________________________________ -->
1948<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1949Instruction</a> </div>
1950<div class="doc_text">
1951<h5>Syntax:</h5>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1952<pre>
1953 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]1954 ret void <i>; Return from void function</i>
1955</pre>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1956
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1957<h5>Overview:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1958
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1959<p>The '<tt>ret</tt>' instruction is used to return control flow (and
1960optionally a value) from a function back to the caller.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1961<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1962returns a value and then causes control flow, and one that just causes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1963control flow to occur.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1964
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1965<h5>Arguments:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1966
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1967<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
1968the return value. The type of the return value must be a
1969'<a href="#t_firstclass">first class</a>' type.</p>
1970
1971<p>A function is not <a href="#wellformed">well formed</a> if
1972it it has a non-void return type and contains a '<tt>ret</tt>'
1973instruction with no return value or a return value with a type that
1974does not match its type, or if it has a void return type and contains
1975a '<tt>ret</tt>' instruction with a return 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>Semantics:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1978
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1979<p>When the '<tt>ret</tt>' instruction is executed, control flow
1980returns back to the calling function's context. If the caller is a "<a
1981 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
1982the instruction after the call. If the caller was an "<a
1983 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1984at the beginning of the "normal" destination block. If the instruction
1985returns a value, that value shall set the call or invoke instruction's
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]1986return value.</p>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1987
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1988<h5>Example:</h5>
Chris Lattner43030e72008-04-23 04:59:35 +0000[diff] [blame]1989
1990<pre>
1991 ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]1992 ret void <i>; Return from a void function</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]1993 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]1994</pre>
1995</div>
1996<!-- _______________________________________________________________________ -->
1997<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
1998<div class="doc_text">
1999<h5>Syntax:</h5>
2000<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
2001</pre>
2002<h5>Overview:</h5>
2003<p>The '<tt>br</tt>' instruction is used to cause control flow to
2004transfer to a different basic block in the current function. There are
2005two forms of this instruction, corresponding to a conditional branch
2006and an unconditional branch.</p>
2007<h5>Arguments:</h5>
2008<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
2009single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
2010unconditional form of the '<tt>br</tt>' instruction takes a single
2011'<tt>label</tt>' value as a target.</p>
2012<h5>Semantics:</h5>
2013<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
2014argument is evaluated. If the value is <tt>true</tt>, control flows
2015to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2016control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
2017<h5>Example:</h5>
2018<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
2019 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
2020</div>
2021<!-- _______________________________________________________________________ -->
2022<div class="doc_subsubsection">
2023 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2024</div>
2025
2026<div class="doc_text">
2027<h5>Syntax:</h5>
2028
2029<pre>
2030 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2031</pre>
2032
2033<h5>Overview:</h5>
2034
2035<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2036several different places. It is a generalization of the '<tt>br</tt>'
2037instruction, allowing a branch to occur to one of many possible
2038destinations.</p>
2039
2040
2041<h5>Arguments:</h5>
2042
2043<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2044comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2045an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2046table is not allowed to contain duplicate constant entries.</p>
2047
2048<h5>Semantics:</h5>
2049
2050<p>The <tt>switch</tt> instruction specifies a table of values and
2051destinations. When the '<tt>switch</tt>' instruction is executed, this
2052table is searched for the given value. If the value is found, control flow is
2053transfered to the corresponding destination; otherwise, control flow is
2054transfered to the default destination.</p>
2055
2056<h5>Implementation:</h5>
2057
2058<p>Depending on properties of the target machine and the particular
2059<tt>switch</tt> instruction, this instruction may be code generated in different
2060ways. For example, it could be generated as a series of chained conditional
2061branches or with a lookup table.</p>
2062
2063<h5>Example:</h5>
2064
2065<pre>
2066 <i>; Emulate a conditional br instruction</i>
2067 %Val = <a href="#i_zext">zext</a> i1 %value to i32
2068 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
2069
2070 <i>; Emulate an unconditional br instruction</i>
2071 switch i32 0, label %dest [ ]
2072
2073 <i>; Implement a jump table:</i>
2074 switch i32 %val, label %otherwise [ i32 0, label %onzero
2075 i32 1, label %onone
2076 i32 2, label %ontwo ]
2077</pre>
2078</div>
2079
2080<!-- _______________________________________________________________________ -->
2081<div class="doc_subsubsection">
2082 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2083</div>
2084
2085<div class="doc_text">
2086
2087<h5>Syntax:</h5>
2088
2089<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2090 &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]2091 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
2092</pre>
2093
2094<h5>Overview:</h5>
2095
2096<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2097function, with the possibility of control flow transfer to either the
2098'<tt>normal</tt>' label or the
2099'<tt>exception</tt>' label. If the callee function returns with the
2100"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2101"normal" label. If the callee (or any indirect callees) returns with the "<a
2102href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]2103continued at the dynamically nearest "exception" label.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2104
2105<h5>Arguments:</h5>
2106
2107<p>This instruction requires several arguments:</p>
2108
2109<ol>
2110 <li>
2111 The optional "cconv" marker indicates which <a href="#callingconv">calling
2112 convention</a> the call should use. If none is specified, the call defaults
2113 to using C calling conventions.
2114 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2115
2116 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2117 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2118 and '<tt>inreg</tt>' attributes are valid here.</li>
2119
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2120 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2121 function value being invoked. In most cases, this is a direct function
2122 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2123 an arbitrary pointer to function value.
2124 </li>
2125
2126 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2127 function to be invoked. </li>
2128
2129 <li>'<tt>function args</tt>': argument list whose types match the function
2130 signature argument types. If the function signature indicates the function
2131 accepts a variable number of arguments, the extra arguments can be
2132 specified. </li>
2133
2134 <li>'<tt>normal label</tt>': the label reached when the called function
2135 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2136
2137 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2138 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2139
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]2140 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]2141 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2142 '<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2143</ol>
2144
2145<h5>Semantics:</h5>
2146
2147<p>This instruction is designed to operate as a standard '<tt><a
2148href="#i_call">call</a></tt>' instruction in most regards. The primary
2149difference is that it establishes an association with a label, which is used by
2150the runtime library to unwind the stack.</p>
2151
2152<p>This instruction is used in languages with destructors to ensure that proper
2153cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2154exception. Additionally, this is important for implementation of
2155'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2156
2157<h5>Example:</h5>
2158<pre>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2159 %retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2160 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewyckya1c11a12008-03-16 07:18:12 +0000[diff] [blame]2161 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2162 unwind label %TestCleanup <i>; {i32}:retval set</i>
2163</pre>
2164</div>
2165
2166
2167<!-- _______________________________________________________________________ -->
2168
2169<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2170Instruction</a> </div>
2171
2172<div class="doc_text">
2173
2174<h5>Syntax:</h5>
2175<pre>
2176 unwind
2177</pre>
2178
2179<h5>Overview:</h5>
2180
2181<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2182at the first callee in the dynamic call stack which used an <a
2183href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2184primarily used to implement exception handling.</p>
2185
2186<h5>Semantics:</h5>
2187
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]2188<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2189immediately halt. The dynamic call stack is then searched for the first <a
2190href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2191execution continues at the "exceptional" destination block specified by the
2192<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2193dynamic call chain, undefined behavior results.</p>
2194</div>
2195
2196<!-- _______________________________________________________________________ -->
2197
2198<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2199Instruction</a> </div>
2200
2201<div class="doc_text">
2202
2203<h5>Syntax:</h5>
2204<pre>
2205 unreachable
2206</pre>
2207
2208<h5>Overview:</h5>
2209
2210<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2211instruction is used to inform the optimizer that a particular portion of the
2212code is not reachable. This can be used to indicate that the code after a
2213no-return function cannot be reached, and other facts.</p>
2214
2215<h5>Semantics:</h5>
2216
2217<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2218</div>
2219
2220
2221
2222<!-- ======================================================================= -->
2223<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
2224<div class="doc_text">
2225<p>Binary operators are used to do most of the computation in a
Chris Lattnerab596d92008-04-01 18:47:32 +0000[diff] [blame]2226program. They require two operands of the same type, execute an operation on them, and
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2227produce a single value. The operands might represent
2228multiple 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]2229The result value has the same type as its operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2230<p>There are several different binary operators:</p>
2231</div>
2232<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2233<div class="doc_subsubsection">
2234 <a name="i_add">'<tt>add</tt>' Instruction</a>
2235</div>
2236
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2237<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2238
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2239<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2240
2241<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2242 &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]2243</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2244
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2245<h5>Overview:</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 '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2248
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2249<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2250
2251<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2252 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2253 <a href="#t_vector">vector</a> values. Both arguments must have identical
2254 types.</p>
2255
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2256<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2257
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2258<p>The value produced is the integer or floating point sum of the two
2259operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2260
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2261<p>If an integer sum has unsigned overflow, the result returned is the
2262mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2263the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2264
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2265<p>Because LLVM integers use a two's complement representation, this
2266instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2267
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2268<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2269
2270<pre>
2271 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2272</pre>
2273</div>
2274<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2275<div class="doc_subsubsection">
2276 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2277</div>
2278
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2279<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2280
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2281<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2282
2283<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2284 &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]2285</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2286
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2287<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2288
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2289<p>The '<tt>sub</tt>' instruction returns the difference of its two
2290operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2291
2292<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2293'<tt>neg</tt>' instruction present in most other intermediate
2294representations.</p>
2295
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2296<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2297
2298<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2299 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2300 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2301 types.</p>
2302
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2303<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2304
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2305<p>The value produced is the integer or floating point difference of
2306the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2307
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2308<p>If an integer difference has unsigned overflow, the result returned is the
2309mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2310the result.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2311
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2312<p>Because LLVM integers use a two's complement representation, this
2313instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2314
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2315<h5>Example:</h5>
2316<pre>
2317 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
2318 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
2319</pre>
2320</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2321
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2322<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2323<div class="doc_subsubsection">
2324 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2325</div>
2326
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2327<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2328
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2329<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2330<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]2331</pre>
2332<h5>Overview:</h5>
2333<p>The '<tt>mul</tt>' instruction returns the product of its two
2334operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2335
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2336<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2337
2338<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2339href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2340or <a href="#t_vector">vector</a> values. Both arguments must have identical
2341types.</p>
2342
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2343<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2344
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2345<p>The value produced is the integer or floating point product of the
2346two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2347
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2348<p>If the result of an integer multiplication has unsigned overflow,
2349the result returned is the mathematical result modulo
23502<sup>n</sup>, where n is the bit width of the result.</p>
2351<p>Because LLVM integers use a two's complement representation, and the
2352result is the same width as the operands, this instruction returns the
2353correct result for both signed and unsigned integers. If a full product
2354(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2355should be sign-extended or zero-extended as appropriate to the
2356width of the full product.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2357<h5>Example:</h5>
2358<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
2359</pre>
2360</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2361
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2362<!-- _______________________________________________________________________ -->
2363<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2364</a></div>
2365<div class="doc_text">
2366<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2367<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]2368</pre>
2369<h5>Overview:</h5>
2370<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2371operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2372
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2373<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2374
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2375<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2376<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2377values. Both arguments must have identical types.</p>
2378
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2379<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2380
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2381<p>The value produced is the unsigned integer quotient of the two operands.</p>
2382<p>Note that unsigned integer division and signed integer division are distinct
2383operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2384<p>Division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2385<h5>Example:</h5>
2386<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2387</pre>
2388</div>
2389<!-- _______________________________________________________________________ -->
2390<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2391</a> </div>
2392<div class="doc_text">
2393<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2394<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2395 &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]2396</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2397
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2398<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2399
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2400<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2401operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2402
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2403<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2404
2405<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2406<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2407values. Both arguments must have identical types.</p>
2408
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2409<h5>Semantics:</h5>
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2410<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]2411<p>Note that signed integer division and unsigned integer division are distinct
2412operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2413<p>Division by zero leads to undefined behavior. Overflow also leads to
2414undefined behavior; this is a rare case, but can occur, for example,
2415by doing a 32-bit division of -2147483648 by -1.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2416<h5>Example:</h5>
2417<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
2418</pre>
2419</div>
2420<!-- _______________________________________________________________________ -->
2421<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
2422Instruction</a> </div>
2423<div class="doc_text">
2424<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2425<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2426 &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]2427</pre>
2428<h5>Overview:</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 '<tt>fdiv</tt>' instruction returns the quotient of its two
2431operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2432
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2433<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2435<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2436<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2437of floating point values. Both arguments must have identical types.</p>
2438
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2439<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2440
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2441<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2442
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2443<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2444
2445<pre>
2446 &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]2447</pre>
2448</div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2449
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2450<!-- _______________________________________________________________________ -->
2451<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2452</div>
2453<div class="doc_text">
2454<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2455<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]2456</pre>
2457<h5>Overview:</h5>
2458<p>The '<tt>urem</tt>' instruction returns the remainder from the
2459unsigned division of its two arguments.</p>
2460<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2461<p>The two arguments to the '<tt>urem</tt>' instruction must be
2462<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2463values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2464<h5>Semantics:</h5>
2465<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2466This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2467<p>Note that unsigned integer remainder and signed integer remainder are
2468distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2469<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2470<h5>Example:</h5>
2471<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2472</pre>
2473
2474</div>
2475<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2476<div class="doc_subsubsection">
2477 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2478</div>
2479
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2480<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2481
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2482<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2483
2484<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2485 &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]2486</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2488<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2489
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2490<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman3e3fd8c2007-11-05 23:35:22 +0000[diff] [blame]2491signed division of its two operands. This instruction can also take
2492<a href="#t_vector">vector</a> versions of the values in which case
2493the elements must be integers.</p>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]2494
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2495<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2496
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2497<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2498<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2499values. Both arguments must have identical types.</p>
2500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2501<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2502
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2503<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2504has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2505operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2506a value. For more information about the difference, see <a
2507 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
2508Math Forum</a>. For a table of how this is implemented in various languages,
2509please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
2510Wikipedia: modulo operation</a>.</p>
Chris Lattner9aba1e22008-01-28 00:36:27 +0000[diff] [blame]2511<p>Note that signed integer remainder and unsigned integer remainder are
2512distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2513<p>Taking the remainder of a division by zero leads to undefined behavior.
2514Overflow also leads to undefined behavior; this is a rare case, but can occur,
2515for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2516(The remainder doesn't actually overflow, but this rule lets srem be
2517implemented using instructions that return both the result of the division
2518and the remainder.)</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2519<h5>Example:</h5>
2520<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
2521</pre>
2522
2523</div>
2524<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2525<div class="doc_subsubsection">
2526 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2527
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2528<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2529
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2530<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2531<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]2532</pre>
2533<h5>Overview:</h5>
2534<p>The '<tt>frem</tt>' instruction returns the remainder from the
2535division of its two operands.</p>
2536<h5>Arguments:</h5>
2537<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2538<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2539of floating point values. Both arguments must have identical types.</p>
2540
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2541<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2542
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2543<p>This instruction returns the <i>remainder</i> of a division.
2544The remainder has the same sign as the dividend.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2545
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2546<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2547
2548<pre>
2549 &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]2550</pre>
2551</div>
2552
2553<!-- ======================================================================= -->
2554<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2555Operations</a> </div>
2556<div class="doc_text">
2557<p>Bitwise binary operators are used to do various forms of
2558bit-twiddling in a program. They are generally very efficient
2559instructions and can commonly be strength reduced from other
Chris Lattnerdc15b1d2008-04-01 18:45:27 +0000[diff] [blame]2560instructions. They require two operands of the same type, execute an operation on them,
2561and 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]2562</div>
2563
2564<!-- _______________________________________________________________________ -->
2565<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2566Instruction</a> </div>
2567<div class="doc_text">
2568<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2569<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]2570</pre>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2571
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2572<h5>Overview:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2573
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2574<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2575the left a specified number of bits.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2576
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2577<h5>Arguments:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2578
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2579<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2580 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2581type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2582
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2583<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2584
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2585<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2586where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
2587equal 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]2588
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2589<h5>Example:</h5><pre>
2590 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2591 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2592 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2593 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2594</pre>
2595</div>
2596<!-- _______________________________________________________________________ -->
2597<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2598Instruction</a> </div>
2599<div class="doc_text">
2600<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2601<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]2602</pre>
2603
2604<h5>Overview:</h5>
2605<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2606operand shifted to the right a specified number of bits with zero fill.</p>
2607
2608<h5>Arguments:</h5>
2609<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2610<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]2611type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2612
2613<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2614
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615<p>This instruction always performs a logical shift right operation. The most
2616significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2617shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
2618the number of bits in <tt>op1</tt>, the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2619
2620<h5>Example:</h5>
2621<pre>
2622 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2623 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2624 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2625 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2626 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2627</pre>
2628</div>
2629
2630<!-- _______________________________________________________________________ -->
2631<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2632Instruction</a> </div>
2633<div class="doc_text">
2634
2635<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2636<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]2637</pre>
2638
2639<h5>Overview:</h5>
2640<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2641operand shifted to the right a specified number of bits with sign extension.</p>
2642
2643<h5>Arguments:</h5>
2644<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2645<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]2646type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2647
2648<h5>Semantics:</h5>
2649<p>This instruction always performs an arithmetic shift right operation,
2650The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2651of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
2652larger than the number of bits in <tt>op1</tt>, the result is undefined.
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2653</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2654
2655<h5>Example:</h5>
2656<pre>
2657 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2658 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2659 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2660 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2661 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2662</pre>
2663</div>
2664
2665<!-- _______________________________________________________________________ -->
2666<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2667Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2668
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2669<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2670
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2671<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2672
2673<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2674 &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]2675</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2677<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2680its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2681
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2682<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2683
2684<p>The two arguments to the '<tt>and</tt>' instruction must be
2685<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2686values. Both arguments must have identical types.</p>
2687
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2688<h5>Semantics:</h5>
2689<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2690<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2691<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2692<table border="1" cellspacing="0" cellpadding="4">
2693 <tbody>
2694 <tr>
2695 <td>In0</td>
2696 <td>In1</td>
2697 <td>Out</td>
2698 </tr>
2699 <tr>
2700 <td>0</td>
2701 <td>0</td>
2702 <td>0</td>
2703 </tr>
2704 <tr>
2705 <td>0</td>
2706 <td>1</td>
2707 <td>0</td>
2708 </tr>
2709 <tr>
2710 <td>1</td>
2711 <td>0</td>
2712 <td>0</td>
2713 </tr>
2714 <tr>
2715 <td>1</td>
2716 <td>1</td>
2717 <td>1</td>
2718 </tr>
2719 </tbody>
2720</table>
2721</div>
2722<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2723<pre>
2724 &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]2725 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2726 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2727</pre>
2728</div>
2729<!-- _______________________________________________________________________ -->
2730<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2731<div class="doc_text">
2732<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2733<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]2734</pre>
2735<h5>Overview:</h5>
2736<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2737or of its two operands.</p>
2738<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2739
2740<p>The two arguments to the '<tt>or</tt>' instruction must be
2741<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2742values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2743<h5>Semantics:</h5>
2744<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2745<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2746<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2747<table border="1" cellspacing="0" cellpadding="4">
2748 <tbody>
2749 <tr>
2750 <td>In0</td>
2751 <td>In1</td>
2752 <td>Out</td>
2753 </tr>
2754 <tr>
2755 <td>0</td>
2756 <td>0</td>
2757 <td>0</td>
2758 </tr>
2759 <tr>
2760 <td>0</td>
2761 <td>1</td>
2762 <td>1</td>
2763 </tr>
2764 <tr>
2765 <td>1</td>
2766 <td>0</td>
2767 <td>1</td>
2768 </tr>
2769 <tr>
2770 <td>1</td>
2771 <td>1</td>
2772 <td>1</td>
2773 </tr>
2774 </tbody>
2775</table>
2776</div>
2777<h5>Example:</h5>
2778<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2779 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2780 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2781</pre>
2782</div>
2783<!-- _______________________________________________________________________ -->
2784<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2785Instruction</a> </div>
2786<div class="doc_text">
2787<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2788<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]2789</pre>
2790<h5>Overview:</h5>
2791<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2792or of its two operands. The <tt>xor</tt> is used to implement the
2793"one's complement" operation, which is the "~" operator in C.</p>
2794<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2795<p>The two arguments to the '<tt>xor</tt>' instruction must be
2796<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2797values. Both arguments must have identical types.</p>
2798
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2799<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2800
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2801<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2802<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2803<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2804<table border="1" cellspacing="0" cellpadding="4">
2805 <tbody>
2806 <tr>
2807 <td>In0</td>
2808 <td>In1</td>
2809 <td>Out</td>
2810 </tr>
2811 <tr>
2812 <td>0</td>
2813 <td>0</td>
2814 <td>0</td>
2815 </tr>
2816 <tr>
2817 <td>0</td>
2818 <td>1</td>
2819 <td>1</td>
2820 </tr>
2821 <tr>
2822 <td>1</td>
2823 <td>0</td>
2824 <td>1</td>
2825 </tr>
2826 <tr>
2827 <td>1</td>
2828 <td>1</td>
2829 <td>0</td>
2830 </tr>
2831 </tbody>
2832</table>
2833</div>
2834<p> </p>
2835<h5>Example:</h5>
2836<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2837 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2838 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2839 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2840</pre>
2841</div>
2842
2843<!-- ======================================================================= -->
2844<div class="doc_subsection">
2845 <a name="vectorops">Vector Operations</a>
2846</div>
2847
2848<div class="doc_text">
2849
2850<p>LLVM supports several instructions to represent vector operations in a
2851target-independent manner. These instructions cover the element-access and
2852vector-specific operations needed to process vectors effectively. While LLVM
2853does directly support these vector operations, many sophisticated algorithms
2854will want to use target-specific intrinsics to take full advantage of a specific
2855target.</p>
2856
2857</div>
2858
2859<!-- _______________________________________________________________________ -->
2860<div class="doc_subsubsection">
2861 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2862</div>
2863
2864<div class="doc_text">
2865
2866<h5>Syntax:</h5>
2867
2868<pre>
2869 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2870</pre>
2871
2872<h5>Overview:</h5>
2873
2874<p>
2875The '<tt>extractelement</tt>' instruction extracts a single scalar
2876element from a vector at a specified index.
2877</p>
2878
2879
2880<h5>Arguments:</h5>
2881
2882<p>
2883The first operand of an '<tt>extractelement</tt>' instruction is a
2884value of <a href="#t_vector">vector</a> type. The second operand is
2885an index indicating the position from which to extract the element.
2886The index may be a variable.</p>
2887
2888<h5>Semantics:</h5>
2889
2890<p>
2891The result is a scalar of the same type as the element type of
2892<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2893<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2894results are undefined.
2895</p>
2896
2897<h5>Example:</h5>
2898
2899<pre>
2900 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2901</pre>
2902</div>
2903
2904
2905<!-- _______________________________________________________________________ -->
2906<div class="doc_subsubsection">
2907 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2908</div>
2909
2910<div class="doc_text">
2911
2912<h5>Syntax:</h5>
2913
2914<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2915 &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]2916</pre>
2917
2918<h5>Overview:</h5>
2919
2920<p>
2921The '<tt>insertelement</tt>' instruction inserts a scalar
2922element into a vector at a specified index.
2923</p>
2924
2925
2926<h5>Arguments:</h5>
2927
2928<p>
2929The first operand of an '<tt>insertelement</tt>' instruction is a
2930value of <a href="#t_vector">vector</a> type. The second operand is a
2931scalar value whose type must equal the element type of the first
2932operand. The third operand is an index indicating the position at
2933which to insert the value. The index may be a variable.</p>
2934
2935<h5>Semantics:</h5>
2936
2937<p>
2938The result is a vector of the same type as <tt>val</tt>. Its
2939element values are those of <tt>val</tt> except at position
2940<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2941exceeds the length of <tt>val</tt>, the results are undefined.
2942</p>
2943
2944<h5>Example:</h5>
2945
2946<pre>
2947 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2948</pre>
2949</div>
2950
2951<!-- _______________________________________________________________________ -->
2952<div class="doc_subsubsection">
2953 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2954</div>
2955
2956<div class="doc_text">
2957
2958<h5>Syntax:</h5>
2959
2960<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2961 &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]2962</pre>
2963
2964<h5>Overview:</h5>
2965
2966<p>
2967The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2968from two input vectors, returning a vector with the same element type as
2969the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2970</p>
2971
2972<h5>Arguments:</h5>
2973
2974<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2975The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2976with types that match each other. The third argument is a shuffle mask whose
2977element type is always 'i32'. The result of the instruction is a vector whose
2978length is the same as the shuffle mask and whose element type is the same as
2979the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2980</p>
2981
2982<p>
2983The shuffle mask operand is required to be a constant vector with either
2984constant integer or undef values.
2985</p>
2986
2987<h5>Semantics:</h5>
2988
2989<p>
2990The elements of the two input vectors are numbered from left to right across
2991both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2992the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2993gets. The element selector may be undef (meaning "don't care") and the second
2994operand may be undef if performing a shuffle from only one vector.
2995</p>
2996
2997<h5>Example:</h5>
2998
2999<pre>
3000 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3001 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3002 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3003 &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]3004 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3005 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3006 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3007 &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]3008</pre>
3009</div>
3010
3011
3012<!-- ======================================================================= -->
3013<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3014 <a name="aggregateops">Aggregate Operations</a>
3015</div>
3016
3017<div class="doc_text">
3018
3019<p>LLVM supports several instructions for working with aggregate values.
3020</p>
3021
3022</div>
3023
3024<!-- _______________________________________________________________________ -->
3025<div class="doc_subsubsection">
3026 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3027</div>
3028
3029<div class="doc_text">
3030
3031<h5>Syntax:</h5>
3032
3033<pre>
3034 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3035</pre>
3036
3037<h5>Overview:</h5>
3038
3039<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3040The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3041or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3042</p>
3043
3044
3045<h5>Arguments:</h5>
3046
3047<p>
3048The first operand of an '<tt>extractvalue</tt>' instruction is a
3049value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3050type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3051in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3052'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3053</p>
3054
3055<h5>Semantics:</h5>
3056
3057<p>
3058The result is the value at the position in the aggregate specified by
3059the index operands.
3060</p>
3061
3062<h5>Example:</h5>
3063
3064<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3065 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3066</pre>
3067</div>
3068
3069
3070<!-- _______________________________________________________________________ -->
3071<div class="doc_subsubsection">
3072 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3073</div>
3074
3075<div class="doc_text">
3076
3077<h5>Syntax:</h5>
3078
3079<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3080 &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]3081</pre>
3082
3083<h5>Overview:</h5>
3084
3085<p>
3086The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3087into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3088</p>
3089
3090
3091<h5>Arguments:</h5>
3092
3093<p>
3094The first operand of an '<tt>insertvalue</tt>' instruction is a
3095value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3096The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3097The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3098indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3099indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3100'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3101The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3102by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3103</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3104
3105<h5>Semantics:</h5>
3106
3107<p>
3108The result is an aggregate of the same type as <tt>val</tt>. Its
3109value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3110specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3111</p>
3112
3113<h5>Example:</h5>
3114
3115<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3116 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3117</pre>
3118</div>
3119
3120
3121<!-- ======================================================================= -->
3122<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3123 <a name="memoryops">Memory Access and Addressing Operations</a>
3124</div>
3125
3126<div class="doc_text">
3127
3128<p>A key design point of an SSA-based representation is how it
3129represents memory. In LLVM, no memory locations are in SSA form, which
3130makes things very simple. This section describes how to read, write,
3131allocate, and free memory in LLVM.</p>
3132
3133</div>
3134
3135<!-- _______________________________________________________________________ -->
3136<div class="doc_subsubsection">
3137 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3138</div>
3139
3140<div class="doc_text">
3141
3142<h5>Syntax:</h5>
3143
3144<pre>
3145 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3146</pre>
3147
3148<h5>Overview:</h5>
3149
3150<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3151heap and returns a pointer to it. The object is always allocated in the generic
3152address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3153
3154<h5>Arguments:</h5>
3155
3156<p>The '<tt>malloc</tt>' instruction allocates
3157<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3158bytes of memory from the operating system and returns a pointer of the
3159appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3160number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3161If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3162be aligned to at least that boundary. If not specified, or if zero, the target can
3163choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3164
3165<p>'<tt>type</tt>' must be a sized type.</p>
3166
3167<h5>Semantics:</h5>
3168
3169<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3170a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3171result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172
3173<h5>Example:</h5>
3174
3175<pre>
3176 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3177
3178 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3179 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3180 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3181 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3182 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3183</pre>
3184</div>
3185
3186<!-- _______________________________________________________________________ -->
3187<div class="doc_subsubsection">
3188 <a name="i_free">'<tt>free</tt>' Instruction</a>
3189</div>
3190
3191<div class="doc_text">
3192
3193<h5>Syntax:</h5>
3194
3195<pre>
3196 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3197</pre>
3198
3199<h5>Overview:</h5>
3200
3201<p>The '<tt>free</tt>' instruction returns memory back to the unused
3202memory heap to be reallocated in the future.</p>
3203
3204<h5>Arguments:</h5>
3205
3206<p>'<tt>value</tt>' shall be a pointer value that points to a value
3207that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3208instruction.</p>
3209
3210<h5>Semantics:</h5>
3211
3212<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3213after this instruction executes. If the pointer is null, the operation
3214is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3215
3216<h5>Example:</h5>
3217
3218<pre>
3219 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3220 free [4 x i8]* %array
3221</pre>
3222</div>
3223
3224<!-- _______________________________________________________________________ -->
3225<div class="doc_subsubsection">
3226 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3227</div>
3228
3229<div class="doc_text">
3230
3231<h5>Syntax:</h5>
3232
3233<pre>
3234 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3235</pre>
3236
3237<h5>Overview:</h5>
3238
3239<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3240currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3241returns to its caller. The object is always allocated in the generic address
3242space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3243
3244<h5>Arguments:</h5>
3245
3246<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3247bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3248appropriate type to the program. If "NumElements" is specified, it is the
3249number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3250If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3251to be aligned to at least that boundary. If not specified, or if zero, the target
3252can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3253
3254<p>'<tt>type</tt>' may be any sized type.</p>
3255
3256<h5>Semantics:</h5>
3257
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3258<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3259there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3260memory is automatically released when the function returns. The '<tt>alloca</tt>'
3261instruction is commonly used to represent automatic variables that must
3262have an address available. When the function returns (either with the <tt><a
3263 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]3264instructions), the memory is reclaimed. Allocating zero bytes
3265is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3266
3267<h5>Example:</h5>
3268
3269<pre>
3270 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3271 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3272 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3273 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3274</pre>
3275</div>
3276
3277<!-- _______________________________________________________________________ -->
3278<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3279Instruction</a> </div>
3280<div class="doc_text">
3281<h5>Syntax:</h5>
3282<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>
3283<h5>Overview:</h5>
3284<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3285<h5>Arguments:</h5>
3286<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3287address from which to load. The pointer must point to a <a
3288 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3289marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3290the number or order of execution of this <tt>load</tt> with other
3291volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3292instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3293<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3294The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3295(that is, the alignment of the memory address). A value of 0 or an
3296omitted "align" argument means that the operation has the preferential
3297alignment for the target. It is the responsibility of the code emitter
3298to ensure that the alignment information is correct. Overestimating
3299the alignment results in an undefined behavior. Underestimating the
3300alignment may produce less efficient code. An alignment of 1 is always
3301safe.
3302</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3303<h5>Semantics:</h5>
3304<p>The location of memory pointed to is loaded.</p>
3305<h5>Examples:</h5>
3306<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3307 <a
3308 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3309 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3310</pre>
3311</div>
3312<!-- _______________________________________________________________________ -->
3313<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3314Instruction</a> </div>
3315<div class="doc_text">
3316<h5>Syntax:</h5>
3317<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3318 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3319</pre>
3320<h5>Overview:</h5>
3321<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3322<h5>Arguments:</h5>
3323<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3324to 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]3325operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3326of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3327operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3328optimizer is not allowed to modify the number or order of execution of
3329this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3330 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3331<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3332The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3333(that is, the alignment of the memory address). A value of 0 or an
3334omitted "align" argument means that the operation has the preferential
3335alignment for the target. It is the responsibility of the code emitter
3336to ensure that the alignment information is correct. Overestimating
3337the alignment results in an undefined behavior. Underestimating the
3338alignment may produce less efficient code. An alignment of 1 is always
3339safe.
3340</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3341<h5>Semantics:</h5>
3342<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3343at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3344<h5>Example:</h5>
3345<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3346 store i32 3, i32* %ptr <i>; yields {void}</i>
3347 %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]3348</pre>
3349</div>
3350
3351<!-- _______________________________________________________________________ -->
3352<div class="doc_subsubsection">
3353 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3354</div>
3355
3356<div class="doc_text">
3357<h5>Syntax:</h5>
3358<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3359 &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]3360</pre>
3361
3362<h5>Overview:</h5>
3363
3364<p>
3365The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3366subelement of an aggregate data structure. It performs address calculation only
3367and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3368
3369<h5>Arguments:</h5>
3370
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3371<p>The first argument is always a pointer, and forms the basis of the
3372calculation. The remaining arguments are indices, that indicate which of the
3373elements of the aggregate object are indexed. The interpretation of each index
3374is dependent on the type being indexed into. The first index always indexes the
3375pointer value given as the first argument, the second index indexes a value of
3376the type pointed to (not necessarily the value directly pointed to, since the
3377first index can be non-zero), etc. The first type indexed into must be a pointer
3378value, subsequent types can be arrays, vectors and structs. Note that subsequent
3379types being indexed into can never be pointers, since that would require loading
3380the pointer before continuing calculation.</p>
3381
3382<p>The type of each index argument depends on the type it is indexing into.
3383When indexing into a (packed) structure, only <tt>i32</tt> integer
3384<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3385only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3386will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3387
3388<p>For example, let's consider a C code fragment and how it gets
3389compiled to LLVM:</p>
3390
3391<div class="doc_code">
3392<pre>
3393struct RT {
3394 char A;
3395 int B[10][20];
3396 char C;
3397};
3398struct ST {
3399 int X;
3400 double Y;
3401 struct RT Z;
3402};
3403
3404int *foo(struct ST *s) {
3405 return &amp;s[1].Z.B[5][13];
3406}
3407</pre>
3408</div>
3409
3410<p>The LLVM code generated by the GCC frontend is:</p>
3411
3412<div class="doc_code">
3413<pre>
3414%RT = type { i8 , [10 x [20 x i32]], i8 }
3415%ST = type { i32, double, %RT }
3416
3417define i32* %foo(%ST* %s) {
3418entry:
3419 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3420 ret i32* %reg
3421}
3422</pre>
3423</div>
3424
3425<h5>Semantics:</h5>
3426
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3427<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3428type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3429}</tt>' type, a structure. The second index indexes into the third element of
3430the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3431i8 }</tt>' type, another structure. The third index indexes into the second
3432element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3433array. The two dimensions of the array are subscripted into, yielding an
3434'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3435to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3436
3437<p>Note that it is perfectly legal to index partially through a
3438structure, returning a pointer to an inner element. Because of this,
3439the LLVM code for the given testcase is equivalent to:</p>
3440
3441<pre>
3442 define i32* %foo(%ST* %s) {
3443 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3444 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3445 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3446 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3447 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3448 ret i32* %t5
3449 }
3450</pre>
3451
3452<p>Note that it is undefined to access an array out of bounds: array and
3453pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3454The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3455defined to be accessible as variable length arrays, which requires access
3456beyond the zero'th element.</p>
3457
3458<p>The getelementptr instruction is often confusing. For some more insight
3459into how it works, see <a href="GetElementPtr.html">the getelementptr
3460FAQ</a>.</p>
3461
3462<h5>Example:</h5>
3463
3464<pre>
3465 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3466 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3467 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3468 %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]3469 <i>; yields i8*:eptr</i>
3470 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3471</pre>
3472</div>
3473
3474<!-- ======================================================================= -->
3475<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3476</div>
3477<div class="doc_text">
3478<p>The instructions in this category are the conversion instructions (casting)
3479which all take a single operand and a type. They perform various bit conversions
3480on the operand.</p>
3481</div>
3482
3483<!-- _______________________________________________________________________ -->
3484<div class="doc_subsubsection">
3485 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3486</div>
3487<div class="doc_text">
3488
3489<h5>Syntax:</h5>
3490<pre>
3491 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3492</pre>
3493
3494<h5>Overview:</h5>
3495<p>
3496The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3497</p>
3498
3499<h5>Arguments:</h5>
3500<p>
3501The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3502be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3503and type of the result, which must be an <a href="#t_integer">integer</a>
3504type. The bit size of <tt>value</tt> must be larger than the bit size of
3505<tt>ty2</tt>. Equal sized types are not allowed.</p>
3506
3507<h5>Semantics:</h5>
3508<p>
3509The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3510and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3511larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3512It will always truncate bits.</p>
3513
3514<h5>Example:</h5>
3515<pre>
3516 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3517 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3518 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3519</pre>
3520</div>
3521
3522<!-- _______________________________________________________________________ -->
3523<div class="doc_subsubsection">
3524 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3525</div>
3526<div class="doc_text">
3527
3528<h5>Syntax:</h5>
3529<pre>
3530 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3531</pre>
3532
3533<h5>Overview:</h5>
3534<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3535<tt>ty2</tt>.</p>
3536
3537
3538<h5>Arguments:</h5>
3539<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3540<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3541also be of <a href="#t_integer">integer</a> type. The bit size of the
3542<tt>value</tt> must be smaller than the bit size of the destination type,
3543<tt>ty2</tt>.</p>
3544
3545<h5>Semantics:</h5>
3546<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3547bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3548
3549<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3550
3551<h5>Example:</h5>
3552<pre>
3553 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3554 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3555</pre>
3556</div>
3557
3558<!-- _______________________________________________________________________ -->
3559<div class="doc_subsubsection">
3560 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3561</div>
3562<div class="doc_text">
3563
3564<h5>Syntax:</h5>
3565<pre>
3566 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3567</pre>
3568
3569<h5>Overview:</h5>
3570<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3571
3572<h5>Arguments:</h5>
3573<p>
3574The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3575<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3576also be of <a href="#t_integer">integer</a> type. The bit size of the
3577<tt>value</tt> must be smaller than the bit size of the destination type,
3578<tt>ty2</tt>.</p>
3579
3580<h5>Semantics:</h5>
3581<p>
3582The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3583bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3584the type <tt>ty2</tt>.</p>
3585
3586<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3587
3588<h5>Example:</h5>
3589<pre>
3590 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3591 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3592</pre>
3593</div>
3594
3595<!-- _______________________________________________________________________ -->
3596<div class="doc_subsubsection">
3597 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3598</div>
3599
3600<div class="doc_text">
3601
3602<h5>Syntax:</h5>
3603
3604<pre>
3605 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3606</pre>
3607
3608<h5>Overview:</h5>
3609<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3610<tt>ty2</tt>.</p>
3611
3612
3613<h5>Arguments:</h5>
3614<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3615 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3616cast it to. The size of <tt>value</tt> must be larger than the size of
3617<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3618<i>no-op cast</i>.</p>
3619
3620<h5>Semantics:</h5>
3621<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3622<a href="#t_floating">floating point</a> type to a smaller
3623<a href="#t_floating">floating point</a> type. If the value cannot fit within
3624the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3625
3626<h5>Example:</h5>
3627<pre>
3628 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3629 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3630</pre>
3631</div>
3632
3633<!-- _______________________________________________________________________ -->
3634<div class="doc_subsubsection">
3635 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3636</div>
3637<div class="doc_text">
3638
3639<h5>Syntax:</h5>
3640<pre>
3641 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3642</pre>
3643
3644<h5>Overview:</h5>
3645<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3646floating point value.</p>
3647
3648<h5>Arguments:</h5>
3649<p>The '<tt>fpext</tt>' instruction takes a
3650<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3651and a <a href="#t_floating">floating point</a> type to cast it to. The source
3652type must be smaller than the destination type.</p>
3653
3654<h5>Semantics:</h5>
3655<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3656<a href="#t_floating">floating point</a> type to a larger
3657<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3658used to make a <i>no-op cast</i> because it always changes bits. Use
3659<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3660
3661<h5>Example:</h5>
3662<pre>
3663 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3664 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3665</pre>
3666</div>
3667
3668<!-- _______________________________________________________________________ -->
3669<div class="doc_subsubsection">
3670 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3671</div>
3672<div class="doc_text">
3673
3674<h5>Syntax:</h5>
3675<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3676 &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]3677</pre>
3678
3679<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3680<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3681unsigned integer equivalent of type <tt>ty2</tt>.
3682</p>
3683
3684<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3685<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]3686scalar or vector <a href="#t_floating">floating point</a> value, and a type
3687to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3688type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3689vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3690
3691<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3692<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3693<a href="#t_floating">floating point</a> operand into the nearest (rounding
3694towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3695the results are undefined.</p>
3696
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3697<h5>Example:</h5>
3698<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3699 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3700 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3701 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3702</pre>
3703</div>
3704
3705<!-- _______________________________________________________________________ -->
3706<div class="doc_subsubsection">
3707 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3708</div>
3709<div class="doc_text">
3710
3711<h5>Syntax:</h5>
3712<pre>
3713 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3714</pre>
3715
3716<h5>Overview:</h5>
3717<p>The '<tt>fptosi</tt>' instruction converts
3718<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3719</p>
3720
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3721<h5>Arguments:</h5>
3722<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]3723scalar or vector <a href="#t_floating">floating point</a> value, and a type
3724to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3725type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3726vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3727
3728<h5>Semantics:</h5>
3729<p>The '<tt>fptosi</tt>' instruction converts its
3730<a href="#t_floating">floating point</a> operand into the nearest (rounding
3731towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3732the results are undefined.</p>
3733
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3734<h5>Example:</h5>
3735<pre>
3736 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3737 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3738 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3739</pre>
3740</div>
3741
3742<!-- _______________________________________________________________________ -->
3743<div class="doc_subsubsection">
3744 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3745</div>
3746<div class="doc_text">
3747
3748<h5>Syntax:</h5>
3749<pre>
3750 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3751</pre>
3752
3753<h5>Overview:</h5>
3754<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3755integer and converts that value to the <tt>ty2</tt> type.</p>
3756
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3757<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3758<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3759scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3760to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3761type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3762floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3763
3764<h5>Semantics:</h5>
3765<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3766integer quantity and converts it to the corresponding floating point value. If
3767the value cannot fit in the floating point value, the results are undefined.</p>
3768
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3769<h5>Example:</h5>
3770<pre>
3771 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3772 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3773</pre>
3774</div>
3775
3776<!-- _______________________________________________________________________ -->
3777<div class="doc_subsubsection">
3778 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3779</div>
3780<div class="doc_text">
3781
3782<h5>Syntax:</h5>
3783<pre>
3784 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3785</pre>
3786
3787<h5>Overview:</h5>
3788<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3789integer and converts that value to the <tt>ty2</tt> type.</p>
3790
3791<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3792<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3793scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3794to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3795type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3796floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3797
3798<h5>Semantics:</h5>
3799<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3800integer quantity and converts it to the corresponding floating point value. If
3801the value cannot fit in the floating point value, the results are undefined.</p>
3802
3803<h5>Example:</h5>
3804<pre>
3805 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3806 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3807</pre>
3808</div>
3809
3810<!-- _______________________________________________________________________ -->
3811<div class="doc_subsubsection">
3812 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3813</div>
3814<div class="doc_text">
3815
3816<h5>Syntax:</h5>
3817<pre>
3818 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3819</pre>
3820
3821<h5>Overview:</h5>
3822<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3823the integer type <tt>ty2</tt>.</p>
3824
3825<h5>Arguments:</h5>
3826<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3827must 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]3828<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]3829
3830<h5>Semantics:</h5>
3831<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3832<tt>ty2</tt> by interpreting the pointer value as an integer and either
3833truncating or zero extending that value to the size of the integer type. If
3834<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3835<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3836are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3837change.</p>
3838
3839<h5>Example:</h5>
3840<pre>
3841 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3842 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3843</pre>
3844</div>
3845
3846<!-- _______________________________________________________________________ -->
3847<div class="doc_subsubsection">
3848 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3849</div>
3850<div class="doc_text">
3851
3852<h5>Syntax:</h5>
3853<pre>
3854 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3855</pre>
3856
3857<h5>Overview:</h5>
3858<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3859a pointer type, <tt>ty2</tt>.</p>
3860
3861<h5>Arguments:</h5>
3862<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3863value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3864<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3865
3866<h5>Semantics:</h5>
3867<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3868<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3869the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3870size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3871the size of a pointer then a zero extension is done. If they are the same size,
3872nothing is done (<i>no-op cast</i>).</p>
3873
3874<h5>Example:</h5>
3875<pre>
3876 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3877 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3878 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3879</pre>
3880</div>
3881
3882<!-- _______________________________________________________________________ -->
3883<div class="doc_subsubsection">
3884 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3885</div>
3886<div class="doc_text">
3887
3888<h5>Syntax:</h5>
3889<pre>
3890 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3891</pre>
3892
3893<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3894
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3895<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3896<tt>ty2</tt> without changing any bits.</p>
3897
3898<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3899
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3900<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3901a non-aggregate first class value, and a type to cast it to, which must also be
3902a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3903<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3904and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3905type is a pointer, the destination type must also be a pointer. This
3906instruction supports bitwise conversion of vectors to integers and to vectors
3907of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3908
3909<h5>Semantics:</h5>
3910<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3911<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3912this conversion. The conversion is done as if the <tt>value</tt> had been
3913stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3914converted to other pointer types with this instruction. To convert pointers to
3915other types, use the <a href="#i_inttoptr">inttoptr</a> or
3916<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3917
3918<h5>Example:</h5>
3919<pre>
3920 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3921 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3922 %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]3923</pre>
3924</div>
3925
3926<!-- ======================================================================= -->
3927<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3928<div class="doc_text">
3929<p>The instructions in this category are the "miscellaneous"
3930instructions, which defy better classification.</p>
3931</div>
3932
3933<!-- _______________________________________________________________________ -->
3934<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3935</div>
3936<div class="doc_text">
3937<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3938<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]3939</pre>
3940<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3941<p>The '<tt>icmp</tt>' instruction returns a boolean value or
3942a vector of boolean values based on comparison
3943of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3944<h5>Arguments:</h5>
3945<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3946the condition code indicating the kind of comparison to perform. It is not
3947a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3948</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3949<ol>
3950 <li><tt>eq</tt>: equal</li>
3951 <li><tt>ne</tt>: not equal </li>
3952 <li><tt>ugt</tt>: unsigned greater than</li>
3953 <li><tt>uge</tt>: unsigned greater or equal</li>
3954 <li><tt>ult</tt>: unsigned less than</li>
3955 <li><tt>ule</tt>: unsigned less or equal</li>
3956 <li><tt>sgt</tt>: signed greater than</li>
3957 <li><tt>sge</tt>: signed greater or equal</li>
3958 <li><tt>slt</tt>: signed less than</li>
3959 <li><tt>sle</tt>: signed less or equal</li>
3960</ol>
3961<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3962<a href="#t_pointer">pointer</a>
3963or integer <a href="#t_vector">vector</a> typed.
3964They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3965<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3966<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]3967the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3968yields 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]3969</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3970<ol>
3971 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3972 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3973 </li>
3974 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3975 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3976 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3977 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3979 <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]3980 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3981 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3982 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3983 <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]3984 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3985 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3986 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3987 <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]3988 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3989 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3990 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3991 <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]3992</ol>
3993<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3994values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3995<p>If the operands are integer vectors, then they are compared
3996element by element. The result is an <tt>i1</tt> vector with
3997the same number of elements as the values being compared.
3998Otherwise, the result is an <tt>i1</tt>.
3999</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000
4001<h5>Example:</h5>
4002<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4003 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4004 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4005 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4006 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4007 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4008</pre>
4009</div>
4010
4011<!-- _______________________________________________________________________ -->
4012<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4013</div>
4014<div class="doc_text">
4015<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4016<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]4017</pre>
4018<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4019<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4020or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4021of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4022<p>
4023If the operands are floating point scalars, then the result
4024type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4025</p>
4026<p>If the operands are floating point vectors, then the result type
4027is a vector of boolean with the same number of elements as the
4028operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4029<h5>Arguments:</h5>
4030<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4031the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4032a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4033<ol>
4034 <li><tt>false</tt>: no comparison, always returns false</li>
4035 <li><tt>oeq</tt>: ordered and equal</li>
4036 <li><tt>ogt</tt>: ordered and greater than </li>
4037 <li><tt>oge</tt>: ordered and greater than or equal</li>
4038 <li><tt>olt</tt>: ordered and less than </li>
4039 <li><tt>ole</tt>: ordered and less than or equal</li>
4040 <li><tt>one</tt>: ordered and not equal</li>
4041 <li><tt>ord</tt>: ordered (no nans)</li>
4042 <li><tt>ueq</tt>: unordered or equal</li>
4043 <li><tt>ugt</tt>: unordered or greater than </li>
4044 <li><tt>uge</tt>: unordered or greater than or equal</li>
4045 <li><tt>ult</tt>: unordered or less than </li>
4046 <li><tt>ule</tt>: unordered or less than or equal</li>
4047 <li><tt>une</tt>: unordered or not equal</li>
4048 <li><tt>uno</tt>: unordered (either nans)</li>
4049 <li><tt>true</tt>: no comparison, always returns true</li>
4050</ol>
4051<p><i>Ordered</i> means that neither operand is a QNAN while
4052<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4053<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4054either a <a href="#t_floating">floating point</a> type
4055or a <a href="#t_vector">vector</a> of floating point type.
4056They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4057<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4058<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4059according to the condition code given as <tt>cond</tt>.
4060If the operands are vectors, then the vectors are compared
4061element by element.
4062Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4063always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4064<ol>
4065 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4066 <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]4067 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4068 <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]4069 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4070 <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]4071 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4072 <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]4073 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4074 <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]4075 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076 <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]4077 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4079 <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]4080 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4081 <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]4082 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4083 <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]4084 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4085 <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]4086 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4087 <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]4088 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4089 <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]4090 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4091 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4092 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4093</ol>
4094
4095<h5>Example:</h5>
4096<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]4097 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4098 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4099 &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]4100</pre>
4101</div>
4102
4103<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4104<div class="doc_subsubsection">
4105 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4106</div>
4107<div class="doc_text">
4108<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4109<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]4110</pre>
4111<h5>Overview:</h5>
4112<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4113element-wise comparison of its two integer vector operands.</p>
4114<h5>Arguments:</h5>
4115<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4116the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4117a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4118<ol>
4119 <li><tt>eq</tt>: equal</li>
4120 <li><tt>ne</tt>: not equal </li>
4121 <li><tt>ugt</tt>: unsigned greater than</li>
4122 <li><tt>uge</tt>: unsigned greater or equal</li>
4123 <li><tt>ult</tt>: unsigned less than</li>
4124 <li><tt>ule</tt>: unsigned less or equal</li>
4125 <li><tt>sgt</tt>: signed greater than</li>
4126 <li><tt>sge</tt>: signed greater or equal</li>
4127 <li><tt>slt</tt>: signed less than</li>
4128 <li><tt>sle</tt>: signed less or equal</li>
4129</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4130<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4131<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4132<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4133<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4134according to the condition code given as <tt>cond</tt>. The comparison yields a
4135<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4136identical type as the values being compared. The most significant bit in each
4137element is 1 if the element-wise comparison evaluates to true, and is 0
4138otherwise. All other bits of the result are undefined. The condition codes
4139are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4140instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4141
4142<h5>Example:</h5>
4143<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4144 &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>
4145 &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]4146</pre>
4147</div>
4148
4149<!-- _______________________________________________________________________ -->
4150<div class="doc_subsubsection">
4151 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4152</div>
4153<div class="doc_text">
4154<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4155<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]4156<h5>Overview:</h5>
4157<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4158element-wise comparison of its two floating point vector operands. The output
4159elements have the same width as the input elements.</p>
4160<h5>Arguments:</h5>
4161<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4162the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4163a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4164<ol>
4165 <li><tt>false</tt>: no comparison, always returns false</li>
4166 <li><tt>oeq</tt>: ordered and equal</li>
4167 <li><tt>ogt</tt>: ordered and greater than </li>
4168 <li><tt>oge</tt>: ordered and greater than or equal</li>
4169 <li><tt>olt</tt>: ordered and less than </li>
4170 <li><tt>ole</tt>: ordered and less than or equal</li>
4171 <li><tt>one</tt>: ordered and not equal</li>
4172 <li><tt>ord</tt>: ordered (no nans)</li>
4173 <li><tt>ueq</tt>: unordered or equal</li>
4174 <li><tt>ugt</tt>: unordered or greater than </li>
4175 <li><tt>uge</tt>: unordered or greater than or equal</li>
4176 <li><tt>ult</tt>: unordered or less than </li>
4177 <li><tt>ule</tt>: unordered or less than or equal</li>
4178 <li><tt>une</tt>: unordered or not equal</li>
4179 <li><tt>uno</tt>: unordered (either nans)</li>
4180 <li><tt>true</tt>: no comparison, always returns true</li>
4181</ol>
4182<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4183<a href="#t_floating">floating point</a> typed. They must also be identical
4184types.</p>
4185<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4186<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4187according to the condition code given as <tt>cond</tt>. The comparison yields a
4188<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4189an identical number of elements as the values being compared, and each element
4190having identical with to the width of the floating point elements. The most
4191significant bit in each element is 1 if the element-wise comparison evaluates to
4192true, and is 0 otherwise. All other bits of the result are undefined. The
4193condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4194<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4195
4196<h5>Example:</h5>
4197<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4198 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4199 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4200
4201 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4202 &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]4203</pre>
4204</div>
4205
4206<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4207<div class="doc_subsubsection">
4208 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4209</div>
4210
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4211<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4212
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4213<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4214
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4215<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4216<h5>Overview:</h5>
4217<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4218the SSA graph representing the function.</p>
4219<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221<p>The type of the incoming values is specified with the first type
4222field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4223as arguments, with one pair for each predecessor basic block of the
4224current block. Only values of <a href="#t_firstclass">first class</a>
4225type may be used as the value arguments to the PHI node. Only labels
4226may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4227
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4228<p>There must be no non-phi instructions between the start of a basic
4229block and the PHI instructions: i.e. PHI instructions must be first in
4230a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4231
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4232<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4233
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4234<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4235specified by the pair corresponding to the predecessor basic block that executed
4236just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4237
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4238<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4239<pre>
4240Loop: ; Infinite loop that counts from 0 on up...
4241 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4242 %nextindvar = add i32 %indvar, 1
4243 br label %Loop
4244</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4245</div>
4246
4247<!-- _______________________________________________________________________ -->
4248<div class="doc_subsubsection">
4249 <a name="i_select">'<tt>select</tt>' Instruction</a>
4250</div>
4251
4252<div class="doc_text">
4253
4254<h5>Syntax:</h5>
4255
4256<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4257 &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>
4258
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4259 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4260</pre>
4261
4262<h5>Overview:</h5>
4263
4264<p>
4265The '<tt>select</tt>' instruction is used to choose one value based on a
4266condition, without branching.
4267</p>
4268
4269
4270<h5>Arguments:</h5>
4271
4272<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4273The '<tt>select</tt>' instruction requires an 'i1' value or
4274a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4275condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4276type. If the val1/val2 are vectors and
4277the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4278individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4279</p>
4280
4281<h5>Semantics:</h5>
4282
4283<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4284If 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]4285value argument; otherwise, it returns the second value argument.
4286</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4287<p>
4288If the condition is a vector of i1, then the value arguments must
4289be vectors of the same size, and the selection is done element
4290by element.
4291</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4292
4293<h5>Example:</h5>
4294
4295<pre>
4296 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4297</pre>
4298</div>
4299
4300
4301<!-- _______________________________________________________________________ -->
4302<div class="doc_subsubsection">
4303 <a name="i_call">'<tt>call</tt>' Instruction</a>
4304</div>
4305
4306<div class="doc_text">
4307
4308<h5>Syntax:</h5>
4309<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4310 &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]4311</pre>
4312
4313<h5>Overview:</h5>
4314
4315<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4316
4317<h5>Arguments:</h5>
4318
4319<p>This instruction requires several arguments:</p>
4320
4321<ol>
4322 <li>
4323 <p>The optional "tail" marker indicates whether the callee function accesses
4324 any allocas or varargs in the caller. If the "tail" marker is present, the
4325 function call is eligible for tail call optimization. Note that calls may
4326 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4327 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4328 </li>
4329 <li>
4330 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4331 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4332 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4333 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4334
4335 <li>
4336 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4337 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4338 and '<tt>inreg</tt>' attributes are valid here.</p>
4339 </li>
4340
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4341 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4342 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4343 the type of the return value. Functions that return no value are marked
4344 <tt><a href="#t_void">void</a></tt>.</p>
4345 </li>
4346 <li>
4347 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4348 value being invoked. The argument types must match the types implied by
4349 this signature. This type can be omitted if the function is not varargs
4350 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4351 </li>
4352 <li>
4353 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4354 be invoked. In most cases, this is a direct function invocation, but
4355 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4356 to function value.</p>
4357 </li>
4358 <li>
4359 <p>'<tt>function args</tt>': argument list whose types match the
4360 function signature argument types. All arguments must be of
4361 <a href="#t_firstclass">first class</a> type. If the function signature
4362 indicates the function accepts a variable number of arguments, the extra
4363 arguments can be specified.</p>
4364 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4365 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4366 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4367 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4368 '<tt>readnone</tt>' attributes are valid here.</p>
4369 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4370</ol>
4371
4372<h5>Semantics:</h5>
4373
4374<p>The '<tt>call</tt>' instruction is used to cause control flow to
4375transfer to a specified function, with its incoming arguments bound to
4376the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4377instruction in the called function, control flow continues with the
4378instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4379function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4380
4381<h5>Example:</h5>
4382
4383<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4384 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4385 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4386 %X = tail call i32 @foo() <i>; yields i32</i>
4387 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4388 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4389
4390 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4391 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4392 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4393 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4394 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4395 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4396</pre>
4397
4398</div>
4399
4400<!-- _______________________________________________________________________ -->
4401<div class="doc_subsubsection">
4402 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4403</div>
4404
4405<div class="doc_text">
4406
4407<h5>Syntax:</h5>
4408
4409<pre>
4410 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4411</pre>
4412
4413<h5>Overview:</h5>
4414
4415<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4416the "variable argument" area of a function call. It is used to implement the
4417<tt>va_arg</tt> macro in C.</p>
4418
4419<h5>Arguments:</h5>
4420
4421<p>This instruction takes a <tt>va_list*</tt> value and the type of
4422the argument. It returns a value of the specified argument type and
4423increments the <tt>va_list</tt> to point to the next argument. The
4424actual type of <tt>va_list</tt> is target specific.</p>
4425
4426<h5>Semantics:</h5>
4427
4428<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4429type from the specified <tt>va_list</tt> and causes the
4430<tt>va_list</tt> to point to the next argument. For more information,
4431see the variable argument handling <a href="#int_varargs">Intrinsic
4432Functions</a>.</p>
4433
4434<p>It is legal for this instruction to be called in a function which does not
4435take a variable number of arguments, for example, the <tt>vfprintf</tt>
4436function.</p>
4437
4438<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4439href="#intrinsics">intrinsic function</a> because it takes a type as an
4440argument.</p>
4441
4442<h5>Example:</h5>
4443
4444<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4445
4446</div>
4447
4448<!-- *********************************************************************** -->
4449<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4450<!-- *********************************************************************** -->
4451
4452<div class="doc_text">
4453
4454<p>LLVM supports the notion of an "intrinsic function". These functions have
4455well known names and semantics and are required to follow certain restrictions.
4456Overall, these intrinsics represent an extension mechanism for the LLVM
4457language that does not require changing all of the transformations in LLVM when
4458adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4459
4460<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4461prefix is reserved in LLVM for intrinsic names; thus, function names may not
4462begin with this prefix. Intrinsic functions must always be external functions:
4463you cannot define the body of intrinsic functions. Intrinsic functions may
4464only be used in call or invoke instructions: it is illegal to take the address
4465of an intrinsic function. Additionally, because intrinsic functions are part
4466of the LLVM language, it is required if any are added that they be documented
4467here.</p>
4468
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4469<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4470a family of functions that perform the same operation but on different data
4471types. Because LLVM can represent over 8 million different integer types,
4472overloading is used commonly to allow an intrinsic function to operate on any
4473integer type. One or more of the argument types or the result type can be
4474overloaded to accept any integer type. Argument types may also be defined as
4475exactly matching a previous argument's type or the result type. This allows an
4476intrinsic function which accepts multiple arguments, but needs all of them to
4477be of the same type, to only be overloaded with respect to a single argument or
4478the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4479
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4480<p>Overloaded intrinsics will have the names of its overloaded argument types
4481encoded into its function name, each preceded by a period. Only those types
4482which are overloaded result in a name suffix. Arguments whose type is matched
4483against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4484take an integer of any width and returns an integer of exactly the same integer
4485width. This leads to a family of functions such as
4486<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4487Only one type, the return type, is overloaded, and only one type suffix is
4488required. Because the argument's type is matched against the return type, it
4489does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4490
4491<p>To learn how to add an intrinsic function, please see the
4492<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4493</p>
4494
4495</div>
4496
4497<!-- ======================================================================= -->
4498<div class="doc_subsection">
4499 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4500</div>
4501
4502<div class="doc_text">
4503
4504<p>Variable argument support is defined in LLVM with the <a
4505 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4506intrinsic functions. These functions are related to the similarly
4507named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4508
4509<p>All of these functions operate on arguments that use a
4510target-specific value type "<tt>va_list</tt>". The LLVM assembly
4511language reference manual does not define what this type is, so all
4512transformations should be prepared to handle these functions regardless of
4513the type used.</p>
4514
4515<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4516instruction and the variable argument handling intrinsic functions are
4517used.</p>
4518
4519<div class="doc_code">
4520<pre>
4521define i32 @test(i32 %X, ...) {
4522 ; Initialize variable argument processing
4523 %ap = alloca i8*
4524 %ap2 = bitcast i8** %ap to i8*
4525 call void @llvm.va_start(i8* %ap2)
4526
4527 ; Read a single integer argument
4528 %tmp = va_arg i8** %ap, i32
4529
4530 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4531 %aq = alloca i8*
4532 %aq2 = bitcast i8** %aq to i8*
4533 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4534 call void @llvm.va_end(i8* %aq2)
4535
4536 ; Stop processing of arguments.
4537 call void @llvm.va_end(i8* %ap2)
4538 ret i32 %tmp
4539}
4540
4541declare void @llvm.va_start(i8*)
4542declare void @llvm.va_copy(i8*, i8*)
4543declare void @llvm.va_end(i8*)
4544</pre>
4545</div>
4546
4547</div>
4548
4549<!-- _______________________________________________________________________ -->
4550<div class="doc_subsubsection">
4551 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4552</div>
4553
4554
4555<div class="doc_text">
4556<h5>Syntax:</h5>
4557<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4558<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4559<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4560<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4561href="#i_va_arg">va_arg</a></tt>.</p>
4562
4563<h5>Arguments:</h5>
4564
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4565<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]4566
4567<h5>Semantics:</h5>
4568
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4569<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]4570macro available in C. In a target-dependent way, it initializes the
4571<tt>va_list</tt> element to which the argument points, so that the next call to
4572<tt>va_arg</tt> will produce the first variable argument passed to the function.
4573Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4574last argument of the function as the compiler can figure that out.</p>
4575
4576</div>
4577
4578<!-- _______________________________________________________________________ -->
4579<div class="doc_subsubsection">
4580 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4581</div>
4582
4583<div class="doc_text">
4584<h5>Syntax:</h5>
4585<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4586<h5>Overview:</h5>
4587
4588<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4589which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4590or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4591
4592<h5>Arguments:</h5>
4593
4594<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4595
4596<h5>Semantics:</h5>
4597
4598<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4599macro available in C. In a target-dependent way, it destroys the
4600<tt>va_list</tt> element to which the argument points. Calls to <a
4601href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4602<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4603<tt>llvm.va_end</tt>.</p>
4604
4605</div>
4606
4607<!-- _______________________________________________________________________ -->
4608<div class="doc_subsubsection">
4609 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4610</div>
4611
4612<div class="doc_text">
4613
4614<h5>Syntax:</h5>
4615
4616<pre>
4617 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4618</pre>
4619
4620<h5>Overview:</h5>
4621
4622<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4623from the source argument list to the destination argument list.</p>
4624
4625<h5>Arguments:</h5>
4626
4627<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4628The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4629
4630
4631<h5>Semantics:</h5>
4632
4633<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4634macro available in C. In a target-dependent way, it copies the source
4635<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4636intrinsic is necessary because the <tt><a href="#int_va_start">
4637llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4638example, memory allocation.</p>
4639
4640</div>
4641
4642<!-- ======================================================================= -->
4643<div class="doc_subsection">
4644 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4645</div>
4646
4647<div class="doc_text">
4648
4649<p>
4650LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4651Collection</a> (GC) requires the implementation and generation of these
4652intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4653These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4654stack</a>, as well as garbage collector implementations that require <a
4655href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4656Front-ends for type-safe garbage collected languages should generate these
4657intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4658href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4659</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4660
4661<p>The garbage collection intrinsics only operate on objects in the generic
4662 address space (address space zero).</p>
4663
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4664</div>
4665
4666<!-- _______________________________________________________________________ -->
4667<div class="doc_subsubsection">
4668 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4669</div>
4670
4671<div class="doc_text">
4672
4673<h5>Syntax:</h5>
4674
4675<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4676 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4677</pre>
4678
4679<h5>Overview:</h5>
4680
4681<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4682the code generator, and allows some metadata to be associated with it.</p>
4683
4684<h5>Arguments:</h5>
4685
4686<p>The first argument specifies the address of a stack object that contains the
4687root pointer. The second pointer (which must be either a constant or a global
4688value address) contains the meta-data to be associated with the root.</p>
4689
4690<h5>Semantics:</h5>
4691
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4692<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]4693location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4694the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4695intrinsic may only be used in a function which <a href="#gc">specifies a GC
4696algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4697
4698</div>
4699
4700
4701<!-- _______________________________________________________________________ -->
4702<div class="doc_subsubsection">
4703 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4704</div>
4705
4706<div class="doc_text">
4707
4708<h5>Syntax:</h5>
4709
4710<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4711 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4712</pre>
4713
4714<h5>Overview:</h5>
4715
4716<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4717locations, allowing garbage collector implementations that require read
4718barriers.</p>
4719
4720<h5>Arguments:</h5>
4721
4722<p>The second argument is the address to read from, which should be an address
4723allocated from the garbage collector. The first object is a pointer to the
4724start of the referenced object, if needed by the language runtime (otherwise
4725null).</p>
4726
4727<h5>Semantics:</h5>
4728
4729<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4730instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4731garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4732may only be used in a function which <a href="#gc">specifies a GC
4733algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4734
4735</div>
4736
4737
4738<!-- _______________________________________________________________________ -->
4739<div class="doc_subsubsection">
4740 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4741</div>
4742
4743<div class="doc_text">
4744
4745<h5>Syntax:</h5>
4746
4747<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4748 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4749</pre>
4750
4751<h5>Overview:</h5>
4752
4753<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4754locations, allowing garbage collector implementations that require write
4755barriers (such as generational or reference counting collectors).</p>
4756
4757<h5>Arguments:</h5>
4758
4759<p>The first argument is the reference to store, the second is the start of the
4760object to store it to, and the third is the address of the field of Obj to
4761store to. If the runtime does not require a pointer to the object, Obj may be
4762null.</p>
4763
4764<h5>Semantics:</h5>
4765
4766<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4767instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4768garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4769may only be used in a function which <a href="#gc">specifies a GC
4770algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4771
4772</div>
4773
4774
4775
4776<!-- ======================================================================= -->
4777<div class="doc_subsection">
4778 <a name="int_codegen">Code Generator Intrinsics</a>
4779</div>
4780
4781<div class="doc_text">
4782<p>
4783These intrinsics are provided by LLVM to expose special features that may only
4784be implemented with code generator support.
4785</p>
4786
4787</div>
4788
4789<!-- _______________________________________________________________________ -->
4790<div class="doc_subsubsection">
4791 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4792</div>
4793
4794<div class="doc_text">
4795
4796<h5>Syntax:</h5>
4797<pre>
4798 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4799</pre>
4800
4801<h5>Overview:</h5>
4802
4803<p>
4804The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4805target-specific value indicating the return address of the current function
4806or one of its callers.
4807</p>
4808
4809<h5>Arguments:</h5>
4810
4811<p>
4812The argument to this intrinsic indicates which function to return the address
4813for. Zero indicates the calling function, one indicates its caller, etc. The
4814argument is <b>required</b> to be a constant integer value.
4815</p>
4816
4817<h5>Semantics:</h5>
4818
4819<p>
4820The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4821the return address of the specified call frame, or zero if it cannot be
4822identified. The value returned by this intrinsic is likely to be incorrect or 0
4823for arguments other than zero, so it should only be used for debugging purposes.
4824</p>
4825
4826<p>
4827Note that calling this intrinsic does not prevent function inlining or other
4828aggressive transformations, so the value returned may not be that of the obvious
4829source-language caller.
4830</p>
4831</div>
4832
4833
4834<!-- _______________________________________________________________________ -->
4835<div class="doc_subsubsection">
4836 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4837</div>
4838
4839<div class="doc_text">
4840
4841<h5>Syntax:</h5>
4842<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4843 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4844</pre>
4845
4846<h5>Overview:</h5>
4847
4848<p>
4849The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4850target-specific frame pointer value for the specified stack frame.
4851</p>
4852
4853<h5>Arguments:</h5>
4854
4855<p>
4856The argument to this intrinsic indicates which function to return the frame
4857pointer for. Zero indicates the calling function, one indicates its caller,
4858etc. The argument is <b>required</b> to be a constant integer value.
4859</p>
4860
4861<h5>Semantics:</h5>
4862
4863<p>
4864The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4865the frame address of the specified call frame, or zero if it cannot be
4866identified. The value returned by this intrinsic is likely to be incorrect or 0
4867for arguments other than zero, so it should only be used for debugging purposes.
4868</p>
4869
4870<p>
4871Note that calling this intrinsic does not prevent function inlining or other
4872aggressive transformations, so the value returned may not be that of the obvious
4873source-language caller.
4874</p>
4875</div>
4876
4877<!-- _______________________________________________________________________ -->
4878<div class="doc_subsubsection">
4879 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4880</div>
4881
4882<div class="doc_text">
4883
4884<h5>Syntax:</h5>
4885<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4886 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4887</pre>
4888
4889<h5>Overview:</h5>
4890
4891<p>
4892The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4893the function stack, for use with <a href="#int_stackrestore">
4894<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4895features like scoped automatic variable sized arrays in C99.
4896</p>
4897
4898<h5>Semantics:</h5>
4899
4900<p>
4901This intrinsic returns a opaque pointer value that can be passed to <a
4902href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4903<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4904<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4905state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4906practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4907that were allocated after the <tt>llvm.stacksave</tt> was executed.
4908</p>
4909
4910</div>
4911
4912<!-- _______________________________________________________________________ -->
4913<div class="doc_subsubsection">
4914 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4915</div>
4916
4917<div class="doc_text">
4918
4919<h5>Syntax:</h5>
4920<pre>
4921 declare void @llvm.stackrestore(i8 * %ptr)
4922</pre>
4923
4924<h5>Overview:</h5>
4925
4926<p>
4927The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4928the function stack to the state it was in when the corresponding <a
4929href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4930useful for implementing language features like scoped automatic variable sized
4931arrays in C99.
4932</p>
4933
4934<h5>Semantics:</h5>
4935
4936<p>
4937See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4938</p>
4939
4940</div>
4941
4942
4943<!-- _______________________________________________________________________ -->
4944<div class="doc_subsubsection">
4945 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4946</div>
4947
4948<div class="doc_text">
4949
4950<h5>Syntax:</h5>
4951<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4952 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]4953</pre>
4954
4955<h5>Overview:</h5>
4956
4957
4958<p>
4959The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4960a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4961no
4962effect on the behavior of the program but can change its performance
4963characteristics.
4964</p>
4965
4966<h5>Arguments:</h5>
4967
4968<p>
4969<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4970determining if the fetch should be for a read (0) or write (1), and
4971<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4972locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4973<tt>locality</tt> arguments must be constant integers.
4974</p>
4975
4976<h5>Semantics:</h5>
4977
4978<p>
4979This intrinsic does not modify the behavior of the program. In particular,
4980prefetches cannot trap and do not produce a value. On targets that support this
4981intrinsic, the prefetch can provide hints to the processor cache for better
4982performance.
4983</p>
4984
4985</div>
4986
4987<!-- _______________________________________________________________________ -->
4988<div class="doc_subsubsection">
4989 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4990</div>
4991
4992<div class="doc_text">
4993
4994<h5>Syntax:</h5>
4995<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4996 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4997</pre>
4998
4999<h5>Overview:</h5>
5000
5001
5002<p>
5003The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5004(PC) in a region of
5005code to simulators and other tools. The method is target specific, but it is
5006expected that the marker will use exported symbols to transmit the PC of the
5007marker.
5008The marker makes no guarantees that it will remain with any specific instruction
5009after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5010optimizations. The intended use is to be inserted after optimizations to allow
5011correlations of simulation runs.
5012</p>
5013
5014<h5>Arguments:</h5>
5015
5016<p>
5017<tt>id</tt> is a numerical id identifying the marker.
5018</p>
5019
5020<h5>Semantics:</h5>
5021
5022<p>
5023This intrinsic does not modify the behavior of the program. Backends that do not
5024support this intrinisic may ignore it.
5025</p>
5026
5027</div>
5028
5029<!-- _______________________________________________________________________ -->
5030<div class="doc_subsubsection">
5031 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5032</div>
5033
5034<div class="doc_text">
5035
5036<h5>Syntax:</h5>
5037<pre>
5038 declare i64 @llvm.readcyclecounter( )
5039</pre>
5040
5041<h5>Overview:</h5>
5042
5043
5044<p>
5045The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5046counter register (or similar low latency, high accuracy clocks) on those targets
5047that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5048As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5049should only be used for small timings.
5050</p>
5051
5052<h5>Semantics:</h5>
5053
5054<p>
5055When directly supported, reading the cycle counter should not modify any memory.
5056Implementations are allowed to either return a application specific value or a
5057system wide value. On backends without support, this is lowered to a constant 0.
5058</p>
5059
5060</div>
5061
5062<!-- ======================================================================= -->
5063<div class="doc_subsection">
5064 <a name="int_libc">Standard C Library Intrinsics</a>
5065</div>
5066
5067<div class="doc_text">
5068<p>
5069LLVM provides intrinsics for a few important standard C library functions.
5070These intrinsics allow source-language front-ends to pass information about the
5071alignment of the pointer arguments to the code generator, providing opportunity
5072for more efficient code generation.
5073</p>
5074
5075</div>
5076
5077<!-- _______________________________________________________________________ -->
5078<div class="doc_subsubsection">
5079 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5080</div>
5081
5082<div class="doc_text">
5083
5084<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5085<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5086width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5087<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5088 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5089 i8 &lt;len&gt;, i32 &lt;align&gt;)
5090 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5091 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5092 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5093 i32 &lt;len&gt;, i32 &lt;align&gt;)
5094 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5095 i64 &lt;len&gt;, i32 &lt;align&gt;)
5096</pre>
5097
5098<h5>Overview:</h5>
5099
5100<p>
5101The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5102location to the destination location.
5103</p>
5104
5105<p>
5106Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5107intrinsics do not return a value, and takes an extra alignment argument.
5108</p>
5109
5110<h5>Arguments:</h5>
5111
5112<p>
5113The first argument is a pointer to the destination, the second is a pointer to
5114the source. The third argument is an integer argument
5115specifying the number of bytes to copy, and the fourth argument is the alignment
5116of the source and destination locations.
5117</p>
5118
5119<p>
5120If the call to this intrinisic has an alignment value that is not 0 or 1, then
5121the caller guarantees that both the source and destination pointers are aligned
5122to that boundary.
5123</p>
5124
5125<h5>Semantics:</h5>
5126
5127<p>
5128The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5129location to the destination location, which are not allowed to overlap. It
5130copies "len" bytes of memory over. If the argument is known to be aligned to
5131some boundary, this can be specified as the fourth argument, otherwise it should
5132be set to 0 or 1.
5133</p>
5134</div>
5135
5136
5137<!-- _______________________________________________________________________ -->
5138<div class="doc_subsubsection">
5139 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5140</div>
5141
5142<div class="doc_text">
5143
5144<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5145<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5146width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5147<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5148 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5149 i8 &lt;len&gt;, i32 &lt;align&gt;)
5150 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5151 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5152 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5153 i32 &lt;len&gt;, i32 &lt;align&gt;)
5154 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5155 i64 &lt;len&gt;, i32 &lt;align&gt;)
5156</pre>
5157
5158<h5>Overview:</h5>
5159
5160<p>
5161The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5162location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5163'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5164</p>
5165
5166<p>
5167Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5168intrinsics do not return a value, and takes an extra alignment argument.
5169</p>
5170
5171<h5>Arguments:</h5>
5172
5173<p>
5174The first argument is a pointer to the destination, the second is a pointer to
5175the source. The third argument is an integer argument
5176specifying the number of bytes to copy, and the fourth argument is the alignment
5177of the source and destination locations.
5178</p>
5179
5180<p>
5181If the call to this intrinisic has an alignment value that is not 0 or 1, then
5182the caller guarantees that the source and destination pointers are aligned to
5183that boundary.
5184</p>
5185
5186<h5>Semantics:</h5>
5187
5188<p>
5189The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5190location to the destination location, which may overlap. It
5191copies "len" bytes of memory over. If the argument is known to be aligned to
5192some boundary, this can be specified as the fourth argument, otherwise it should
5193be set to 0 or 1.
5194</p>
5195</div>
5196
5197
5198<!-- _______________________________________________________________________ -->
5199<div class="doc_subsubsection">
5200 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5201</div>
5202
5203<div class="doc_text">
5204
5205<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5206<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5207width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5208<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5209 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5210 i8 &lt;len&gt;, i32 &lt;align&gt;)
5211 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5212 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5213 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5214 i32 &lt;len&gt;, i32 &lt;align&gt;)
5215 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5216 i64 &lt;len&gt;, i32 &lt;align&gt;)
5217</pre>
5218
5219<h5>Overview:</h5>
5220
5221<p>
5222The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5223byte value.
5224</p>
5225
5226<p>
5227Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5228does not return a value, and takes an extra alignment argument.
5229</p>
5230
5231<h5>Arguments:</h5>
5232
5233<p>
5234The first argument is a pointer to the destination to fill, the second is the
5235byte value to fill it with, the third argument is an integer
5236argument specifying the number of bytes to fill, and the fourth argument is the
5237known alignment of destination location.
5238</p>
5239
5240<p>
5241If the call to this intrinisic has an alignment value that is not 0 or 1, then
5242the caller guarantees that the destination pointer is aligned to that boundary.
5243</p>
5244
5245<h5>Semantics:</h5>
5246
5247<p>
5248The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5249the
5250destination location. If the argument is known to be aligned to some boundary,
5251this can be specified as the fourth argument, otherwise it should be set to 0 or
52521.
5253</p>
5254</div>
5255
5256
5257<!-- _______________________________________________________________________ -->
5258<div class="doc_subsubsection">
5259 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5260</div>
5261
5262<div class="doc_text">
5263
5264<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5265<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]5266floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5267types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5268<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5269 declare float @llvm.sqrt.f32(float %Val)
5270 declare double @llvm.sqrt.f64(double %Val)
5271 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5272 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5273 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5274</pre>
5275
5276<h5>Overview:</h5>
5277
5278<p>
5279The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5280returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5281<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5282negative numbers other than -0.0 (which allows for better optimization, because
5283there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5284defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5285</p>
5286
5287<h5>Arguments:</h5>
5288
5289<p>
5290The argument and return value are floating point numbers of the same type.
5291</p>
5292
5293<h5>Semantics:</h5>
5294
5295<p>
5296This function returns the sqrt of the specified operand if it is a nonnegative
5297floating point number.
5298</p>
5299</div>
5300
5301<!-- _______________________________________________________________________ -->
5302<div class="doc_subsubsection">
5303 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5304</div>
5305
5306<div class="doc_text">
5307
5308<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5309<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]5310floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5311types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5312<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5313 declare float @llvm.powi.f32(float %Val, i32 %power)
5314 declare double @llvm.powi.f64(double %Val, i32 %power)
5315 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5316 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5317 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5318</pre>
5319
5320<h5>Overview:</h5>
5321
5322<p>
5323The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5324specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5325multiplications is not defined. When a vector of floating point type is
5326used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5327</p>
5328
5329<h5>Arguments:</h5>
5330
5331<p>
5332The second argument is an integer power, and the first is a value to raise to
5333that power.
5334</p>
5335
5336<h5>Semantics:</h5>
5337
5338<p>
5339This function returns the first value raised to the second power with an
5340unspecified sequence of rounding operations.</p>
5341</div>
5342
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5343<!-- _______________________________________________________________________ -->
5344<div class="doc_subsubsection">
5345 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5346</div>
5347
5348<div class="doc_text">
5349
5350<h5>Syntax:</h5>
5351<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5352floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5353types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5354<pre>
5355 declare float @llvm.sin.f32(float %Val)
5356 declare double @llvm.sin.f64(double %Val)
5357 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5358 declare fp128 @llvm.sin.f128(fp128 %Val)
5359 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5360</pre>
5361
5362<h5>Overview:</h5>
5363
5364<p>
5365The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5366</p>
5367
5368<h5>Arguments:</h5>
5369
5370<p>
5371The argument and return value are floating point numbers of the same type.
5372</p>
5373
5374<h5>Semantics:</h5>
5375
5376<p>
5377This function returns the sine of the specified operand, returning the
5378same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5379conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5380</div>
5381
5382<!-- _______________________________________________________________________ -->
5383<div class="doc_subsubsection">
5384 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5385</div>
5386
5387<div class="doc_text">
5388
5389<h5>Syntax:</h5>
5390<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5391floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5392types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5393<pre>
5394 declare float @llvm.cos.f32(float %Val)
5395 declare double @llvm.cos.f64(double %Val)
5396 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5397 declare fp128 @llvm.cos.f128(fp128 %Val)
5398 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5399</pre>
5400
5401<h5>Overview:</h5>
5402
5403<p>
5404The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5405</p>
5406
5407<h5>Arguments:</h5>
5408
5409<p>
5410The argument and return value are floating point numbers of the same type.
5411</p>
5412
5413<h5>Semantics:</h5>
5414
5415<p>
5416This function returns the cosine of the specified operand, returning the
5417same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5418conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5419</div>
5420
5421<!-- _______________________________________________________________________ -->
5422<div class="doc_subsubsection">
5423 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5424</div>
5425
5426<div class="doc_text">
5427
5428<h5>Syntax:</h5>
5429<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5430floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5431types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5432<pre>
5433 declare float @llvm.pow.f32(float %Val, float %Power)
5434 declare double @llvm.pow.f64(double %Val, double %Power)
5435 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5436 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5437 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5438</pre>
5439
5440<h5>Overview:</h5>
5441
5442<p>
5443The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5444specified (positive or negative) power.
5445</p>
5446
5447<h5>Arguments:</h5>
5448
5449<p>
5450The second argument is a floating point power, and the first is a value to
5451raise to that power.
5452</p>
5453
5454<h5>Semantics:</h5>
5455
5456<p>
5457This function returns the first value raised to the second power,
5458returning the
5459same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5460conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5461</div>
5462
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5463
5464<!-- ======================================================================= -->
5465<div class="doc_subsection">
5466 <a name="int_manip">Bit Manipulation Intrinsics</a>
5467</div>
5468
5469<div class="doc_text">
5470<p>
5471LLVM provides intrinsics for a few important bit manipulation operations.
5472These allow efficient code generation for some algorithms.
5473</p>
5474
5475</div>
5476
5477<!-- _______________________________________________________________________ -->
5478<div class="doc_subsubsection">
5479 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5480</div>
5481
5482<div class="doc_text">
5483
5484<h5>Syntax:</h5>
5485<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5486type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5487<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5488 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5489 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5490 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5491</pre>
5492
5493<h5>Overview:</h5>
5494
5495<p>
5496The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5497values with an even number of bytes (positive multiple of 16 bits). These are
5498useful for performing operations on data that is not in the target's native
5499byte order.
5500</p>
5501
5502<h5>Semantics:</h5>
5503
5504<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5505The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5506and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5507intrinsic returns an i32 value that has the four bytes of the input i32
5508swapped, 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]5509i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5510<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5511additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5512</p>
5513
5514</div>
5515
5516<!-- _______________________________________________________________________ -->
5517<div class="doc_subsubsection">
5518 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5519</div>
5520
5521<div class="doc_text">
5522
5523<h5>Syntax:</h5>
5524<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]5525width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5526<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5527 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5528 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5529 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5530 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5531 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5532</pre>
5533
5534<h5>Overview:</h5>
5535
5536<p>
5537The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5538value.
5539</p>
5540
5541<h5>Arguments:</h5>
5542
5543<p>
5544The only argument is the value to be counted. The argument may be of any
5545integer type. The return type must match the argument type.
5546</p>
5547
5548<h5>Semantics:</h5>
5549
5550<p>
5551The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5552</p>
5553</div>
5554
5555<!-- _______________________________________________________________________ -->
5556<div class="doc_subsubsection">
5557 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5558</div>
5559
5560<div class="doc_text">
5561
5562<h5>Syntax:</h5>
5563<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]5564integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5565<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5566 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5567 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5568 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5569 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5570 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5571</pre>
5572
5573<h5>Overview:</h5>
5574
5575<p>
5576The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5577leading zeros in a variable.
5578</p>
5579
5580<h5>Arguments:</h5>
5581
5582<p>
5583The only argument is the value to be counted. The argument may be of any
5584integer type. The return type must match the argument type.
5585</p>
5586
5587<h5>Semantics:</h5>
5588
5589<p>
5590The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5591in a variable. If the src == 0 then the result is the size in bits of the type
5592of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5593</p>
5594</div>
5595
5596
5597
5598<!-- _______________________________________________________________________ -->
5599<div class="doc_subsubsection">
5600 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5601</div>
5602
5603<div class="doc_text">
5604
5605<h5>Syntax:</h5>
5606<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]5607integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5608<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5609 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5610 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5611 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5612 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5613 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5614</pre>
5615
5616<h5>Overview:</h5>
5617
5618<p>
5619The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5620trailing zeros.
5621</p>
5622
5623<h5>Arguments:</h5>
5624
5625<p>
5626The only argument is the value to be counted. The argument may be of any
5627integer type. The return type must match the argument type.
5628</p>
5629
5630<h5>Semantics:</h5>
5631
5632<p>
5633The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5634in a variable. If the src == 0 then the result is the size in bits of the type
5635of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5636</p>
5637</div>
5638
5639<!-- _______________________________________________________________________ -->
5640<div class="doc_subsubsection">
5641 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5642</div>
5643
5644<div class="doc_text">
5645
5646<h5>Syntax:</h5>
5647<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5648on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5649<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5650 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5651 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5652</pre>
5653
5654<h5>Overview:</h5>
5655<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5656range of bits from an integer value and returns them in the same bit width as
5657the original value.</p>
5658
5659<h5>Arguments:</h5>
5660<p>The first argument, <tt>%val</tt> and the result may be integer types of
5661any bit width but they must have the same bit width. The second and third
5662arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5663
5664<h5>Semantics:</h5>
5665<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5666of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5667<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5668operates in forward mode.</p>
5669<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5670right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5671only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5672<ol>
5673 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5674 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5675 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5676 to determine the number of bits to retain.</li>
5677 <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]5678 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5679</ol>
5680<p>In reverse mode, a similar computation is made except that the bits are
5681returned in the reverse order. So, for example, if <tt>X</tt> has the value
5682<tt>i16 0x0ACF (101011001111)</tt> and we apply
5683<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5684<tt>i16 0x0026 (000000100110)</tt>.</p>
5685</div>
5686
5687<div class="doc_subsubsection">
5688 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5689</div>
5690
5691<div class="doc_text">
5692
5693<h5>Syntax:</h5>
5694<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5695on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5696<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5697 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5698 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]5699</pre>
5700
5701<h5>Overview:</h5>
5702<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5703of bits in an integer value with another integer value. It returns the integer
5704with the replaced bits.</p>
5705
5706<h5>Arguments:</h5>
5707<p>The first argument, <tt>%val</tt> and the result may be integer types of
5708any bit width but they must have the same bit width. <tt>%val</tt> is the value
5709whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5710integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5711type since they specify only a bit index.</p>
5712
5713<h5>Semantics:</h5>
5714<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5715of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5716<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5717operates in forward mode.</p>
5718<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5719truncating it down to the size of the replacement area or zero extending it
5720up to that size.</p>
5721<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5722are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5723in <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]5724to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5725<p>In reverse mode, a similar computation is made except that the bits are
5726reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5727<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]5728<h5>Examples:</h5>
5729<pre>
5730 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5731 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5732 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5733 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5734 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5735</pre>
5736</div>
5737
5738<!-- ======================================================================= -->
5739<div class="doc_subsection">
5740 <a name="int_debugger">Debugger Intrinsics</a>
5741</div>
5742
5743<div class="doc_text">
5744<p>
5745The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5746are described in the <a
5747href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5748Debugging</a> document.
5749</p>
5750</div>
5751
5752
5753<!-- ======================================================================= -->
5754<div class="doc_subsection">
5755 <a name="int_eh">Exception Handling Intrinsics</a>
5756</div>
5757
5758<div class="doc_text">
5759<p> The LLVM exception handling intrinsics (which all start with
5760<tt>llvm.eh.</tt> prefix), are described in the <a
5761href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5762Handling</a> document. </p>
5763</div>
5764
5765<!-- ======================================================================= -->
5766<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5767 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5768</div>
5769
5770<div class="doc_text">
5771<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5772 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5773 the <tt>nest</tt> attribute, from a function. The result is a callable
5774 function pointer lacking the nest parameter - the caller does not need
5775 to provide a value for it. Instead, the value to use is stored in
5776 advance in a "trampoline", a block of memory usually allocated
5777 on the stack, which also contains code to splice the nest value into the
5778 argument list. This is used to implement the GCC nested function address
5779 extension.
5780</p>
5781<p>
5782 For example, if the function is
5783 <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]5784 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]5785<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5786 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5787 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5788 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5789 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5790</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5791 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5792 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5793</div>
5794
5795<!-- _______________________________________________________________________ -->
5796<div class="doc_subsubsection">
5797 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5798</div>
5799<div class="doc_text">
5800<h5>Syntax:</h5>
5801<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5802declare 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]5803</pre>
5804<h5>Overview:</h5>
5805<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5806 This fills the memory pointed to by <tt>tramp</tt> with code
5807 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5808</p>
5809<h5>Arguments:</h5>
5810<p>
5811 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5812 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5813 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5814 intrinsic. Note that the size and the alignment are target-specific - LLVM
5815 currently provides no portable way of determining them, so a front-end that
5816 generates this intrinsic needs to have some target-specific knowledge.
5817 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]5818</p>
5819<h5>Semantics:</h5>
5820<p>
5821 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5822 dependent code, turning it into a function. A pointer to this function is
5823 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5824 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5825 before being called. The new function's signature is the same as that of
5826 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5827 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5828 of pointer type. Calling the new function is equivalent to calling
5829 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5830 missing <tt>nest</tt> argument. If, after calling
5831 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5832 modified, then the effect of any later call to the returned function pointer is
5833 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5834</p>
5835</div>
5836
5837<!-- ======================================================================= -->
5838<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5839 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5840</div>
5841
5842<div class="doc_text">
5843<p>
5844 These intrinsic functions expand the "universal IR" of LLVM to represent
5845 hardware constructs for atomic operations and memory synchronization. This
5846 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5847 is aimed at a low enough level to allow any programming models or APIs
5848 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5849 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5850 hardware behavior. Just as hardware provides a "universal IR" for source
5851 languages, it also provides a starting point for developing a "universal"
5852 atomic operation and synchronization IR.
5853</p>
5854<p>
5855 These do <em>not</em> form an API such as high-level threading libraries,
5856 software transaction memory systems, atomic primitives, and intrinsic
5857 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5858 application libraries. The hardware interface provided by LLVM should allow
5859 a clean implementation of all of these APIs and parallel programming models.
5860 No one model or paradigm should be selected above others unless the hardware
5861 itself ubiquitously does so.
5862
5863</p>
5864</div>
5865
5866<!-- _______________________________________________________________________ -->
5867<div class="doc_subsubsection">
5868 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5869</div>
5870<div class="doc_text">
5871<h5>Syntax:</h5>
5872<pre>
5873declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5874i1 &lt;device&gt; )
5875
5876</pre>
5877<h5>Overview:</h5>
5878<p>
5879 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5880 specific pairs of memory access types.
5881</p>
5882<h5>Arguments:</h5>
5883<p>
5884 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5885 The first four arguments enables a specific barrier as listed below. The fith
5886 argument specifies that the barrier applies to io or device or uncached memory.
5887
5888</p>
5889 <ul>
5890 <li><tt>ll</tt>: load-load barrier</li>
5891 <li><tt>ls</tt>: load-store barrier</li>
5892 <li><tt>sl</tt>: store-load barrier</li>
5893 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5894 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5895 </ul>
5896<h5>Semantics:</h5>
5897<p>
5898 This intrinsic causes the system to enforce some ordering constraints upon
5899 the loads and stores of the program. This barrier does not indicate
5900 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5901 which they occur. For any of the specified pairs of load and store operations
5902 (f.ex. load-load, or store-load), all of the first operations preceding the
5903 barrier will complete before any of the second operations succeeding the
5904 barrier begin. Specifically the semantics for each pairing is as follows:
5905</p>
5906 <ul>
5907 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5908 after the barrier begins.</li>
5909
5910 <li><tt>ls</tt>: All loads before the barrier must complete before any
5911 store after the barrier begins.</li>
5912 <li><tt>ss</tt>: All stores before the barrier must complete before any
5913 store after the barrier begins.</li>
5914 <li><tt>sl</tt>: All stores before the barrier must complete before any
5915 load after the barrier begins.</li>
5916 </ul>
5917<p>
5918 These semantics are applied with a logical "and" behavior when more than one
5919 is enabled in a single memory barrier intrinsic.
5920</p>
5921<p>
5922 Backends may implement stronger barriers than those requested when they do not
5923 support as fine grained a barrier as requested. Some architectures do not
5924 need all types of barriers and on such architectures, these become noops.
5925</p>
5926<h5>Example:</h5>
5927<pre>
5928%ptr = malloc i32
5929 store i32 4, %ptr
5930
5931%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5932 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5933 <i>; guarantee the above finishes</i>
5934 store i32 8, %ptr <i>; before this begins</i>
5935</pre>
5936</div>
5937
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5938<!-- _______________________________________________________________________ -->
5939<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5940 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5941</div>
5942<div class="doc_text">
5943<h5>Syntax:</h5>
5944<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5945 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5946 any integer bit width and for different address spaces. Not all targets
5947 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5948
5949<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5950declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5951declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5952declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5953declare 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]5954
5955</pre>
5956<h5>Overview:</h5>
5957<p>
5958 This loads a value in memory and compares it to a given value. If they are
5959 equal, it stores a new value into the memory.
5960</p>
5961<h5>Arguments:</h5>
5962<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5963 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5964 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5965 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5966 this integer type. While any bit width integer may be used, targets may only
5967 lower representations they support in hardware.
5968
5969</p>
5970<h5>Semantics:</h5>
5971<p>
5972 This entire intrinsic must be executed atomically. It first loads the value
5973 in memory pointed to by <tt>ptr</tt> and compares it with the value
5974 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5975 loaded value is yielded in all cases. This provides the equivalent of an
5976 atomic compare-and-swap operation within the SSA framework.
5977</p>
5978<h5>Examples:</h5>
5979
5980<pre>
5981%ptr = malloc i32
5982 store i32 4, %ptr
5983
5984%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5985%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5986 <i>; yields {i32}:result1 = 4</i>
5987%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5988%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5989
5990%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5991%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5992 <i>; yields {i32}:result2 = 8</i>
5993%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
5994
5995%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
5996</pre>
5997</div>
5998
5999<!-- _______________________________________________________________________ -->
6000<div class="doc_subsubsection">
6001 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6002</div>
6003<div class="doc_text">
6004<h5>Syntax:</h5>
6005
6006<p>
6007 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6008 integer bit width. Not all targets support all bit widths however.</p>
6009<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6010declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6011declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6012declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6013declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6014
6015</pre>
6016<h5>Overview:</h5>
6017<p>
6018 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6019 the value from memory. It then stores the value in <tt>val</tt> in the memory
6020 at <tt>ptr</tt>.
6021</p>
6022<h5>Arguments:</h5>
6023
6024<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6025 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6026 <tt>val</tt> argument and the result must be integers of the same bit width.
6027 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6028 integer type. The targets may only lower integer representations they
6029 support.
6030</p>
6031<h5>Semantics:</h5>
6032<p>
6033 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6034 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6035 equivalent of an atomic swap operation within the SSA framework.
6036
6037</p>
6038<h5>Examples:</h5>
6039<pre>
6040%ptr = malloc i32
6041 store i32 4, %ptr
6042
6043%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6044%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6045 <i>; yields {i32}:result1 = 4</i>
6046%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6047%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6048
6049%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6050%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6051 <i>; yields {i32}:result2 = 8</i>
6052
6053%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6054%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6055</pre>
6056</div>
6057
6058<!-- _______________________________________________________________________ -->
6059<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6060 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6061
6062</div>
6063<div class="doc_text">
6064<h5>Syntax:</h5>
6065<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6066 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]6067 integer bit width. Not all targets support all bit widths however.</p>
6068<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6069declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6070declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6071declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6072declare 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]6073
6074</pre>
6075<h5>Overview:</h5>
6076<p>
6077 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6078 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6079</p>
6080<h5>Arguments:</h5>
6081<p>
6082
6083 The intrinsic takes two arguments, the first a pointer to an integer value
6084 and the second an integer value. The result is also an integer value. These
6085 integer types can have any bit width, but they must all have the same bit
6086 width. The targets may only lower integer representations they support.
6087</p>
6088<h5>Semantics:</h5>
6089<p>
6090 This intrinsic does a series of operations atomically. It first loads the
6091 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6092 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6093</p>
6094
6095<h5>Examples:</h5>
6096<pre>
6097%ptr = malloc i32
6098 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6099%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6100 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6101%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6102 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6103%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6104 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6105%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6106</pre>
6107</div>
6108
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6109<!-- _______________________________________________________________________ -->
6110<div class="doc_subsubsection">
6111 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6112
6113</div>
6114<div class="doc_text">
6115<h5>Syntax:</h5>
6116<p>
6117 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]6118 any integer bit width and for different address spaces. Not all targets
6119 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6120<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6121declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6122declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6123declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6124declare 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]6125
6126</pre>
6127<h5>Overview:</h5>
6128<p>
6129 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6130 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6131</p>
6132<h5>Arguments:</h5>
6133<p>
6134
6135 The intrinsic takes two arguments, the first a pointer to an integer value
6136 and the second an integer value. The result is also an integer value. These
6137 integer types can have any bit width, but they must all have the same bit
6138 width. The targets may only lower integer representations they support.
6139</p>
6140<h5>Semantics:</h5>
6141<p>
6142 This intrinsic does a series of operations atomically. It first loads the
6143 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6144 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6145</p>
6146
6147<h5>Examples:</h5>
6148<pre>
6149%ptr = malloc i32
6150 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6151%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6152 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6153%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6154 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6155%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6156 <i>; yields {i32}:result3 = 2</i>
6157%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6158</pre>
6159</div>
6160
6161<!-- _______________________________________________________________________ -->
6162<div class="doc_subsubsection">
6163 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6164 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6165 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6166 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6167
6168</div>
6169<div class="doc_text">
6170<h5>Syntax:</h5>
6171<p>
6172 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6173 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6174 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6175 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6176<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6177declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6178declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6179declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6180declare 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]6181
6182</pre>
6183
6184<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6185declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6186declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6187declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6188declare 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]6189
6190</pre>
6191
6192<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6193declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6194declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6195declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6196declare 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]6197
6198</pre>
6199
6200<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6201declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6202declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6203declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6204declare 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]6205
6206</pre>
6207<h5>Overview:</h5>
6208<p>
6209 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6210 the value stored in memory at <tt>ptr</tt>. It yields the original value
6211 at <tt>ptr</tt>.
6212</p>
6213<h5>Arguments:</h5>
6214<p>
6215
6216 These intrinsics take two arguments, the first a pointer to an integer value
6217 and the second an integer value. The result is also an integer value. These
6218 integer types can have any bit width, but they must all have the same bit
6219 width. The targets may only lower integer representations they support.
6220</p>
6221<h5>Semantics:</h5>
6222<p>
6223 These intrinsics does a series of operations atomically. They first load the
6224 value stored at <tt>ptr</tt>. They then do the bitwise operation
6225 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6226 value stored at <tt>ptr</tt>.
6227</p>
6228
6229<h5>Examples:</h5>
6230<pre>
6231%ptr = malloc i32
6232 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6233%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6234 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6235%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6236 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6237%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6238 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6239%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6240 <i>; yields {i32}:result3 = FF</i>
6241%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6242</pre>
6243</div>
6244
6245
6246<!-- _______________________________________________________________________ -->
6247<div class="doc_subsubsection">
6248 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6249 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6250 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6251 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6252
6253</div>
6254<div class="doc_text">
6255<h5>Syntax:</h5>
6256<p>
6257 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6258 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6259 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6260 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6261 support all bit widths however.</p>
6262<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6263declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6264declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6265declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6266declare 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]6267
6268</pre>
6269
6270<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6271declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6272declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6273declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6274declare 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]6275
6276</pre>
6277
6278<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6279declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6280declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6281declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6282declare 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]6283
6284</pre>
6285
6286<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6287declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6288declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6289declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6290declare 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]6291
6292</pre>
6293<h5>Overview:</h5>
6294<p>
6295 These intrinsics takes the signed or unsigned minimum or maximum of
6296 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6297 original value at <tt>ptr</tt>.
6298</p>
6299<h5>Arguments:</h5>
6300<p>
6301
6302 These intrinsics take two arguments, the first a pointer to an integer value
6303 and the second an integer value. The result is also an integer value. These
6304 integer types can have any bit width, but they must all have the same bit
6305 width. The targets may only lower integer representations they support.
6306</p>
6307<h5>Semantics:</h5>
6308<p>
6309 These intrinsics does a series of operations atomically. They first load the
6310 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6311 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6312 the original value stored at <tt>ptr</tt>.
6313</p>
6314
6315<h5>Examples:</h5>
6316<pre>
6317%ptr = malloc i32
6318 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6319%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6320 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6321%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6322 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6323%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6324 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6325%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6326 <i>; yields {i32}:result3 = 8</i>
6327%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6328</pre>
6329</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6330
6331<!-- ======================================================================= -->
6332<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6333 <a name="int_general">General Intrinsics</a>
6334</div>
6335
6336<div class="doc_text">
6337<p> This class of intrinsics is designed to be generic and has
6338no specific purpose. </p>
6339</div>
6340
6341<!-- _______________________________________________________________________ -->
6342<div class="doc_subsubsection">
6343 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6344</div>
6345
6346<div class="doc_text">
6347
6348<h5>Syntax:</h5>
6349<pre>
6350 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6351</pre>
6352
6353<h5>Overview:</h5>
6354
6355<p>
6356The '<tt>llvm.var.annotation</tt>' intrinsic
6357</p>
6358
6359<h5>Arguments:</h5>
6360
6361<p>
6362The first argument is a pointer to a value, the second is a pointer to a
6363global string, the third is a pointer to a global string which is the source
6364file name, and the last argument is the line number.
6365</p>
6366
6367<h5>Semantics:</h5>
6368
6369<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6370This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6371This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6372annotations. These have no other defined use, they are ignored by code
6373generation and optimization.
6374</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6375</div>
6376
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6377<!-- _______________________________________________________________________ -->
6378<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6379 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6380</div>
6381
6382<div class="doc_text">
6383
6384<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6385<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6386any integer bit width.
6387</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6388<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6389 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6390 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6391 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6392 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6393 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]6394</pre>
6395
6396<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6397
6398<p>
6399The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6400</p>
6401
6402<h5>Arguments:</h5>
6403
6404<p>
6405The first argument is an integer value (result of some expression),
6406the second is a pointer to a global string, the third is a pointer to a global
6407string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6408It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6409</p>
6410
6411<h5>Semantics:</h5>
6412
6413<p>
6414This intrinsic allows annotations to be put on arbitrary expressions
6415with arbitrary strings. This can be useful for special purpose optimizations
6416that want to look for these annotations. These have no other defined use, they
6417are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6418</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6419</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6420
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6421<!-- _______________________________________________________________________ -->
6422<div class="doc_subsubsection">
6423 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6424</div>
6425
6426<div class="doc_text">
6427
6428<h5>Syntax:</h5>
6429<pre>
6430 declare void @llvm.trap()
6431</pre>
6432
6433<h5>Overview:</h5>
6434
6435<p>
6436The '<tt>llvm.trap</tt>' intrinsic
6437</p>
6438
6439<h5>Arguments:</h5>
6440
6441<p>
6442None
6443</p>
6444
6445<h5>Semantics:</h5>
6446
6447<p>
6448This intrinsics is lowered to the target dependent trap instruction. If the
6449target does not have a trap instruction, this intrinsic will be lowered to the
6450call of the abort() function.
6451</p>
6452</div>
6453
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6454<!-- _______________________________________________________________________ -->
6455<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6456 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6457</div>
6458<div class="doc_text">
6459<h5>Syntax:</h5>
6460<pre>
6461declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6462
6463</pre>
6464<h5>Overview:</h5>
6465<p>
6466 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6467 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6468 it is placed on the stack before local variables.
6469</p>
6470<h5>Arguments:</h5>
6471<p>
6472 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6473 first argument is the value loaded from the stack guard
6474 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6475 has enough space to hold the value of the guard.
6476</p>
6477<h5>Semantics:</h5>
6478<p>
6479 This intrinsic causes the prologue/epilogue inserter to force the position of
6480 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6481 stack. This is to ensure that if a local variable on the stack is overwritten,
6482 it will destroy the value of the guard. When the function exits, the guard on
6483 the stack is checked against the original guard. If they're different, then
6484 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6485</p>
6486</div>
6487
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6488<!-- *********************************************************************** -->
6489<hr>
6490<address>
6491 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
6492 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
6493 <a href="http://validator.w3.org/check/referer"><img
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6494 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6495
6496 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6497 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6498 Last modified: $Date$
6499</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6500
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6501</body>
6502</html>