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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
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2587equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2588If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2589corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2590
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2591<h5>Example:</h5><pre>
2592 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2593 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2594 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2595 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2596 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2597</pre>
2598</div>
2599<!-- _______________________________________________________________________ -->
2600<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2601Instruction</a> </div>
2602<div class="doc_text">
2603<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2604<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]2605</pre>
2606
2607<h5>Overview:</h5>
2608<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2609operand shifted to the right a specified number of bits with zero fill.</p>
2610
2611<h5>Arguments:</h5>
2612<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2613<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]2614type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2615
2616<h5>Semantics:</h5>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2617
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2618<p>This instruction always performs a logical shift right operation. The most
2619significant bits of the result will be filled with zero bits after the
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2620shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2621the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2622vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2623amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2624
2625<h5>Example:</h5>
2626<pre>
2627 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2628 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2629 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2630 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2631 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2632 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2633</pre>
2634</div>
2635
2636<!-- _______________________________________________________________________ -->
2637<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2638Instruction</a> </div>
2639<div class="doc_text">
2640
2641<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2642<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]2643</pre>
2644
2645<h5>Overview:</h5>
2646<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2647operand shifted to the right a specified number of bits with sign extension.</p>
2648
2649<h5>Arguments:</h5>
2650<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanbb1ce942008-07-29 15:49:41 +0000[diff] [blame]2651<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]2652type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2653
2654<h5>Semantics:</h5>
2655<p>This instruction always performs an arithmetic shift right operation,
2656The most significant bits of the result will be filled with the sign bit
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2657of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
Mon P Wangb0f51822008-12-10 08:55:09 +0000[diff] [blame]2658larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2659arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2660corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2661
2662<h5>Example:</h5>
2663<pre>
2664 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2665 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2666 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2667 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerd939d9f2007-10-03 21:01:14 +0000[diff] [blame]2668 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang9901e732008-12-09 05:46:39 +0000[diff] [blame]2669 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2670</pre>
2671</div>
2672
2673<!-- _______________________________________________________________________ -->
2674<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2675Instruction</a> </div>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2676
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2677<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2678
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2679<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2680
2681<pre>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2682 &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]2683</pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2684
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2685<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2686
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2687<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2688its two operands.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2689
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2690<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2691
2692<p>The two arguments to the '<tt>and</tt>' instruction must be
2693<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2694values. Both arguments must have identical types.</p>
2695
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2696<h5>Semantics:</h5>
2697<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
2698<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2699<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2700<table border="1" cellspacing="0" cellpadding="4">
2701 <tbody>
2702 <tr>
2703 <td>In0</td>
2704 <td>In1</td>
2705 <td>Out</td>
2706 </tr>
2707 <tr>
2708 <td>0</td>
2709 <td>0</td>
2710 <td>0</td>
2711 </tr>
2712 <tr>
2713 <td>0</td>
2714 <td>1</td>
2715 <td>0</td>
2716 </tr>
2717 <tr>
2718 <td>1</td>
2719 <td>0</td>
2720 <td>0</td>
2721 </tr>
2722 <tr>
2723 <td>1</td>
2724 <td>1</td>
2725 <td>1</td>
2726 </tr>
2727 </tbody>
2728</table>
2729</div>
2730<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2731<pre>
2732 &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]2733 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2734 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
2735</pre>
2736</div>
2737<!-- _______________________________________________________________________ -->
2738<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
2739<div class="doc_text">
2740<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2741<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]2742</pre>
2743<h5>Overview:</h5>
2744<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2745or of its two operands.</p>
2746<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2747
2748<p>The two arguments to the '<tt>or</tt>' instruction must be
2749<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2750values. Both arguments must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2751<h5>Semantics:</h5>
2752<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
2753<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2754<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2755<table border="1" cellspacing="0" cellpadding="4">
2756 <tbody>
2757 <tr>
2758 <td>In0</td>
2759 <td>In1</td>
2760 <td>Out</td>
2761 </tr>
2762 <tr>
2763 <td>0</td>
2764 <td>0</td>
2765 <td>0</td>
2766 </tr>
2767 <tr>
2768 <td>0</td>
2769 <td>1</td>
2770 <td>1</td>
2771 </tr>
2772 <tr>
2773 <td>1</td>
2774 <td>0</td>
2775 <td>1</td>
2776 </tr>
2777 <tr>
2778 <td>1</td>
2779 <td>1</td>
2780 <td>1</td>
2781 </tr>
2782 </tbody>
2783</table>
2784</div>
2785<h5>Example:</h5>
2786<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2787 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2788 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
2789</pre>
2790</div>
2791<!-- _______________________________________________________________________ -->
2792<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2793Instruction</a> </div>
2794<div class="doc_text">
2795<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]2796<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]2797</pre>
2798<h5>Overview:</h5>
2799<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2800or of its two operands. The <tt>xor</tt> is used to implement the
2801"one's complement" operation, which is the "~" operator in C.</p>
2802<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2803<p>The two arguments to the '<tt>xor</tt>' instruction must be
2804<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2805values. Both arguments must have identical types.</p>
2806
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2807<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]2808
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2809<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
2810<p> </p>
Bill Wendling1e19eac2008-09-07 10:29:20 +0000[diff] [blame]2811<div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2812<table border="1" cellspacing="0" cellpadding="4">
2813 <tbody>
2814 <tr>
2815 <td>In0</td>
2816 <td>In1</td>
2817 <td>Out</td>
2818 </tr>
2819 <tr>
2820 <td>0</td>
2821 <td>0</td>
2822 <td>0</td>
2823 </tr>
2824 <tr>
2825 <td>0</td>
2826 <td>1</td>
2827 <td>1</td>
2828 </tr>
2829 <tr>
2830 <td>1</td>
2831 <td>0</td>
2832 <td>1</td>
2833 </tr>
2834 <tr>
2835 <td>1</td>
2836 <td>1</td>
2837 <td>0</td>
2838 </tr>
2839 </tbody>
2840</table>
2841</div>
2842<p> </p>
2843<h5>Example:</h5>
2844<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2845 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2846 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2847 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
2848</pre>
2849</div>
2850
2851<!-- ======================================================================= -->
2852<div class="doc_subsection">
2853 <a name="vectorops">Vector Operations</a>
2854</div>
2855
2856<div class="doc_text">
2857
2858<p>LLVM supports several instructions to represent vector operations in a
2859target-independent manner. These instructions cover the element-access and
2860vector-specific operations needed to process vectors effectively. While LLVM
2861does directly support these vector operations, many sophisticated algorithms
2862will want to use target-specific intrinsics to take full advantage of a specific
2863target.</p>
2864
2865</div>
2866
2867<!-- _______________________________________________________________________ -->
2868<div class="doc_subsubsection">
2869 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2870</div>
2871
2872<div class="doc_text">
2873
2874<h5>Syntax:</h5>
2875
2876<pre>
2877 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
2878</pre>
2879
2880<h5>Overview:</h5>
2881
2882<p>
2883The '<tt>extractelement</tt>' instruction extracts a single scalar
2884element from a vector at a specified index.
2885</p>
2886
2887
2888<h5>Arguments:</h5>
2889
2890<p>
2891The first operand of an '<tt>extractelement</tt>' instruction is a
2892value of <a href="#t_vector">vector</a> type. The second operand is
2893an index indicating the position from which to extract the element.
2894The index may be a variable.</p>
2895
2896<h5>Semantics:</h5>
2897
2898<p>
2899The result is a scalar of the same type as the element type of
2900<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2901<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2902results are undefined.
2903</p>
2904
2905<h5>Example:</h5>
2906
2907<pre>
2908 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
2909</pre>
2910</div>
2911
2912
2913<!-- _______________________________________________________________________ -->
2914<div class="doc_subsubsection">
2915 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2916</div>
2917
2918<div class="doc_text">
2919
2920<h5>Syntax:</h5>
2921
2922<pre>
Dan Gohmanbcc3c502008-05-12 23:38:42 +0000[diff] [blame]2923 &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]2924</pre>
2925
2926<h5>Overview:</h5>
2927
2928<p>
2929The '<tt>insertelement</tt>' instruction inserts a scalar
2930element into a vector at a specified index.
2931</p>
2932
2933
2934<h5>Arguments:</h5>
2935
2936<p>
2937The first operand of an '<tt>insertelement</tt>' instruction is a
2938value of <a href="#t_vector">vector</a> type. The second operand is a
2939scalar value whose type must equal the element type of the first
2940operand. The third operand is an index indicating the position at
2941which to insert the value. The index may be a variable.</p>
2942
2943<h5>Semantics:</h5>
2944
2945<p>
2946The result is a vector of the same type as <tt>val</tt>. Its
2947element values are those of <tt>val</tt> except at position
2948<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2949exceeds the length of <tt>val</tt>, the results are undefined.
2950</p>
2951
2952<h5>Example:</h5>
2953
2954<pre>
2955 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
2956</pre>
2957</div>
2958
2959<!-- _______________________________________________________________________ -->
2960<div class="doc_subsubsection">
2961 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2962</div>
2963
2964<div class="doc_text">
2965
2966<h5>Syntax:</h5>
2967
2968<pre>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2969 &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]2970</pre>
2971
2972<h5>Overview:</h5>
2973
2974<p>
2975The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2976from two input vectors, returning a vector with the same element type as
2977the input and length that is the same as the shuffle mask.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2978</p>
2979
2980<h5>Arguments:</h5>
2981
2982<p>
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]2983The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2984with types that match each other. The third argument is a shuffle mask whose
2985element type is always 'i32'. The result of the instruction is a vector whose
2986length is the same as the shuffle mask and whose element type is the same as
2987the element type of the first two operands.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]2988</p>
2989
2990<p>
2991The shuffle mask operand is required to be a constant vector with either
2992constant integer or undef values.
2993</p>
2994
2995<h5>Semantics:</h5>
2996
2997<p>
2998The elements of the two input vectors are numbered from left to right across
2999both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wangbff5d9c2008-11-10 04:46:22 +0000[diff] [blame]3000the result vector, which element of the two input vectors the result element
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3001gets. The element selector may be undef (meaning "don't care") and the second
3002operand may be undef if performing a shuffle from only one vector.
3003</p>
3004
3005<h5>Example:</h5>
3006
3007<pre>
3008 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3009 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
3010 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3011 &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]3012 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3013 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3014 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3015 &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]3016</pre>
3017</div>
3018
3019
3020<!-- ======================================================================= -->
3021<div class="doc_subsection">
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3022 <a name="aggregateops">Aggregate Operations</a>
3023</div>
3024
3025<div class="doc_text">
3026
3027<p>LLVM supports several instructions for working with aggregate values.
3028</p>
3029
3030</div>
3031
3032<!-- _______________________________________________________________________ -->
3033<div class="doc_subsubsection">
3034 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3035</div>
3036
3037<div class="doc_text">
3038
3039<h5>Syntax:</h5>
3040
3041<pre>
3042 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3043</pre>
3044
3045<h5>Overview:</h5>
3046
3047<p>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3048The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3049or array element from an aggregate value.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3050</p>
3051
3052
3053<h5>Arguments:</h5>
3054
3055<p>
3056The first operand of an '<tt>extractvalue</tt>' instruction is a
3057value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3058type. The operands are constant indices to specify which value to extract
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3059in a similar manner as indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3060'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3061</p>
3062
3063<h5>Semantics:</h5>
3064
3065<p>
3066The result is the value at the position in the aggregate specified by
3067the index operands.
3068</p>
3069
3070<h5>Example:</h5>
3071
3072<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3073 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3074</pre>
3075</div>
3076
3077
3078<!-- _______________________________________________________________________ -->
3079<div class="doc_subsubsection">
3080 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3081</div>
3082
3083<div class="doc_text">
3084
3085<h5>Syntax:</h5>
3086
3087<pre>
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3088 &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]3089</pre>
3090
3091<h5>Overview:</h5>
3092
3093<p>
3094The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3095into a struct field or array element in an aggregate.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3096</p>
3097
3098
3099<h5>Arguments:</h5>
3100
3101<p>
3102The first operand of an '<tt>insertvalue</tt>' instruction is a
3103value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3104The second operand is a first-class value to insert.
Dan Gohman4f29e422008-05-23 21:53:15 +0000[diff] [blame]3105The following operands are constant indices
Dan Gohmane5febe42008-05-31 00:58:22 +0000[diff] [blame]3106indicating the position at which to insert the value in a similar manner as
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3107indices in a
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3108'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3109The value to insert must have the same type as the value identified
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3110by the indices.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3111</p>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3112
3113<h5>Semantics:</h5>
3114
3115<p>
3116The result is an aggregate of the same type as <tt>val</tt>. Its
3117value is that of <tt>val</tt> except that the value at the position
Dan Gohman6c6dea02008-05-13 18:16:06 +0000[diff] [blame]3118specified by the indices is that of <tt>elt</tt>.
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3119</p>
3120
3121<h5>Example:</h5>
3122
3123<pre>
Dan Gohmanb1aab4e2008-06-23 15:26:37 +0000[diff] [blame]3124 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman74d6faf2008-05-12 23:51:09 +0000[diff] [blame]3125</pre>
3126</div>
3127
3128
3129<!-- ======================================================================= -->
3130<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3131 <a name="memoryops">Memory Access and Addressing Operations</a>
3132</div>
3133
3134<div class="doc_text">
3135
3136<p>A key design point of an SSA-based representation is how it
3137represents memory. In LLVM, no memory locations are in SSA form, which
3138makes things very simple. This section describes how to read, write,
3139allocate, and free memory in LLVM.</p>
3140
3141</div>
3142
3143<!-- _______________________________________________________________________ -->
3144<div class="doc_subsubsection">
3145 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3146</div>
3147
3148<div class="doc_text">
3149
3150<h5>Syntax:</h5>
3151
3152<pre>
3153 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3154</pre>
3155
3156<h5>Overview:</h5>
3157
3158<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3159heap and returns a pointer to it. The object is always allocated in the generic
3160address space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3161
3162<h5>Arguments:</h5>
3163
3164<p>The '<tt>malloc</tt>' instruction allocates
3165<tt>sizeof(&lt;type&gt;)*NumElements</tt>
3166bytes of memory from the operating system and returns a pointer of the
3167appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3168number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3169If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3170be aligned to at least that boundary. If not specified, or if zero, the target can
3171choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3172
3173<p>'<tt>type</tt>' must be a sized type.</p>
3174
3175<h5>Semantics:</h5>
3176
3177<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyff384472008-11-24 03:41:24 +0000[diff] [blame]3178a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3179result is null if there is insufficient memory available.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3180
3181<h5>Example:</h5>
3182
3183<pre>
3184 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
3185
3186 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3187 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3188 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3189 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3190 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
3191</pre>
3192</div>
3193
3194<!-- _______________________________________________________________________ -->
3195<div class="doc_subsubsection">
3196 <a name="i_free">'<tt>free</tt>' Instruction</a>
3197</div>
3198
3199<div class="doc_text">
3200
3201<h5>Syntax:</h5>
3202
3203<pre>
3204 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
3205</pre>
3206
3207<h5>Overview:</h5>
3208
3209<p>The '<tt>free</tt>' instruction returns memory back to the unused
3210memory heap to be reallocated in the future.</p>
3211
3212<h5>Arguments:</h5>
3213
3214<p>'<tt>value</tt>' shall be a pointer value that points to a value
3215that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3216instruction.</p>
3217
3218<h5>Semantics:</h5>
3219
3220<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner329d6532008-04-19 22:41:32 +0000[diff] [blame]3221after this instruction executes. If the pointer is null, the operation
3222is a noop.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3223
3224<h5>Example:</h5>
3225
3226<pre>
3227 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
3228 free [4 x i8]* %array
3229</pre>
3230</div>
3231
3232<!-- _______________________________________________________________________ -->
3233<div class="doc_subsubsection">
3234 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3235</div>
3236
3237<div class="doc_text">
3238
3239<h5>Syntax:</h5>
3240
3241<pre>
3242 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
3243</pre>
3244
3245<h5>Overview:</h5>
3246
3247<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3248currently executing function, to be automatically released when this function
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]3249returns to its caller. The object is always allocated in the generic address
3250space (address space zero).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3251
3252<h5>Arguments:</h5>
3253
3254<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
3255bytes of memory on the runtime stack, returning a pointer of the
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3256appropriate type to the program. If "NumElements" is specified, it is the
3257number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3258If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greif5082cf42008-02-09 22:24:34 +0000[diff] [blame]3259to be aligned to at least that boundary. If not specified, or if zero, the target
3260can choose to align the allocation on any convenient boundary.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3261
3262<p>'<tt>type</tt>' may be any sized type.</p>
3263
3264<h5>Semantics:</h5>
3265
Chris Lattner8b094fc2008-04-19 21:01:16 +0000[diff] [blame]3266<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3267there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3268memory is automatically released when the function returns. The '<tt>alloca</tt>'
3269instruction is commonly used to represent automatic variables that must
3270have an address available. When the function returns (either with the <tt><a
3271 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]3272instructions), the memory is reclaimed. Allocating zero bytes
3273is legal, but the result is undefined.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3274
3275<h5>Example:</h5>
3276
3277<pre>
3278 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3279 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3280 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3281 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
3282</pre>
3283</div>
3284
3285<!-- _______________________________________________________________________ -->
3286<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3287Instruction</a> </div>
3288<div class="doc_text">
3289<h5>Syntax:</h5>
3290<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>
3291<h5>Overview:</h5>
3292<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
3293<h5>Arguments:</h5>
3294<p>The argument to the '<tt>load</tt>' instruction specifies the memory
3295address from which to load. The pointer must point to a <a
3296 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
3297marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
3298the number or order of execution of this <tt>load</tt> with other
3299volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3300instructions. </p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3301<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3302The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3303(that is, the alignment of the memory address). A value of 0 or an
3304omitted "align" argument means that the operation has the preferential
3305alignment for the target. It is the responsibility of the code emitter
3306to ensure that the alignment information is correct. Overestimating
3307the alignment results in an undefined behavior. Underestimating the
3308alignment may produce less efficient code. An alignment of 1 is always
3309safe.
3310</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3311<h5>Semantics:</h5>
3312<p>The location of memory pointed to is loaded.</p>
3313<h5>Examples:</h5>
3314<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
3315 <a
3316 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3317 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
3318</pre>
3319</div>
3320<!-- _______________________________________________________________________ -->
3321<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3322Instruction</a> </div>
3323<div class="doc_text">
3324<h5>Syntax:</h5>
3325<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3326 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3327</pre>
3328<h5>Overview:</h5>
3329<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
3330<h5>Arguments:</h5>
3331<p>There are two arguments to the '<tt>store</tt>' instruction: a value
3332to 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]3333operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3334of the '<tt>&lt;value&gt;</tt>'
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3335operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
3336optimizer is not allowed to modify the number or order of execution of
3337this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3338 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3339<p>
Chris Lattner10368b62008-04-02 00:38:26 +0000[diff] [blame]3340The optional constant "align" argument specifies the alignment of the operation
Chris Lattner21003c82008-01-06 21:04:43 +0000[diff] [blame]3341(that is, the alignment of the memory address). A value of 0 or an
3342omitted "align" argument means that the operation has the preferential
3343alignment for the target. It is the responsibility of the code emitter
3344to ensure that the alignment information is correct. Overestimating
3345the alignment results in an undefined behavior. Underestimating the
3346alignment may produce less efficient code. An alignment of 1 is always
3347safe.
3348</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3349<h5>Semantics:</h5>
3350<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
3351at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
3352<h5>Example:</h5>
3353<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling63ffa142007-10-22 05:10:05 +0000[diff] [blame]3354 store i32 3, i32* %ptr <i>; yields {void}</i>
3355 %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]3356</pre>
3357</div>
3358
3359<!-- _______________________________________________________________________ -->
3360<div class="doc_subsubsection">
3361 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3362</div>
3363
3364<div class="doc_text">
3365<h5>Syntax:</h5>
3366<pre>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3367 &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]3368</pre>
3369
3370<h5>Overview:</h5>
3371
3372<p>
3373The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3374subelement of an aggregate data structure. It performs address calculation only
3375and does not access memory.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3376
3377<h5>Arguments:</h5>
3378
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3379<p>The first argument is always a pointer, and forms the basis of the
3380calculation. The remaining arguments are indices, that indicate which of the
3381elements of the aggregate object are indexed. The interpretation of each index
3382is dependent on the type being indexed into. The first index always indexes the
3383pointer value given as the first argument, the second index indexes a value of
3384the type pointed to (not necessarily the value directly pointed to, since the
3385first index can be non-zero), etc. The first type indexed into must be a pointer
3386value, subsequent types can be arrays, vectors and structs. Note that subsequent
3387types being indexed into can never be pointers, since that would require loading
3388the pointer before continuing calculation.</p>
3389
3390<p>The type of each index argument depends on the type it is indexing into.
3391When indexing into a (packed) structure, only <tt>i32</tt> integer
3392<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3393only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3394will be sign extended to 64-bits if required.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3395
3396<p>For example, let's consider a C code fragment and how it gets
3397compiled to LLVM:</p>
3398
3399<div class="doc_code">
3400<pre>
3401struct RT {
3402 char A;
3403 int B[10][20];
3404 char C;
3405};
3406struct ST {
3407 int X;
3408 double Y;
3409 struct RT Z;
3410};
3411
3412int *foo(struct ST *s) {
3413 return &amp;s[1].Z.B[5][13];
3414}
3415</pre>
3416</div>
3417
3418<p>The LLVM code generated by the GCC frontend is:</p>
3419
3420<div class="doc_code">
3421<pre>
3422%RT = type { i8 , [10 x [20 x i32]], i8 }
3423%ST = type { i32, double, %RT }
3424
3425define i32* %foo(%ST* %s) {
3426entry:
3427 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3428 ret i32* %reg
3429}
3430</pre>
3431</div>
3432
3433<h5>Semantics:</h5>
3434
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3435<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
3436type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
3437}</tt>' type, a structure. The second index indexes into the third element of
3438the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3439i8 }</tt>' type, another structure. The third index indexes into the second
3440element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
3441array. The two dimensions of the array are subscripted into, yielding an
3442'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3443to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
3444
3445<p>Note that it is perfectly legal to index partially through a
3446structure, returning a pointer to an inner element. Because of this,
3447the LLVM code for the given testcase is equivalent to:</p>
3448
3449<pre>
3450 define i32* %foo(%ST* %s) {
3451 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
3452 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3453 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
3454 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3455 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3456 ret i32* %t5
3457 }
3458</pre>
3459
3460<p>Note that it is undefined to access an array out of bounds: array and
3461pointer indexes must always be within the defined bounds of the array type.
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]3462The one exception for this rule is zero length arrays. These arrays are
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3463defined to be accessible as variable length arrays, which requires access
3464beyond the zero'th element.</p>
3465
3466<p>The getelementptr instruction is often confusing. For some more insight
3467into how it works, see <a href="GetElementPtr.html">the getelementptr
3468FAQ</a>.</p>
3469
3470<h5>Example:</h5>
3471
3472<pre>
3473 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman32a080e2008-10-13 13:44:15 +0000[diff] [blame]3474 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3475 <i>; yields i8*:vptr</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3476 %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]3477 <i>; yields i8*:eptr</i>
3478 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3479</pre>
3480</div>
3481
3482<!-- ======================================================================= -->
3483<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
3484</div>
3485<div class="doc_text">
3486<p>The instructions in this category are the conversion instructions (casting)
3487which all take a single operand and a type. They perform various bit conversions
3488on the operand.</p>
3489</div>
3490
3491<!-- _______________________________________________________________________ -->
3492<div class="doc_subsubsection">
3493 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3494</div>
3495<div class="doc_text">
3496
3497<h5>Syntax:</h5>
3498<pre>
3499 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3500</pre>
3501
3502<h5>Overview:</h5>
3503<p>
3504The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3505</p>
3506
3507<h5>Arguments:</h5>
3508<p>
3509The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3510be an <a href="#t_integer">integer</a> type, and a type that specifies the size
3511and type of the result, which must be an <a href="#t_integer">integer</a>
3512type. The bit size of <tt>value</tt> must be larger than the bit size of
3513<tt>ty2</tt>. Equal sized types are not allowed.</p>
3514
3515<h5>Semantics:</h5>
3516<p>
3517The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
3518and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3519larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3520It will always truncate bits.</p>
3521
3522<h5>Example:</h5>
3523<pre>
3524 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
3525 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3526 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
3527</pre>
3528</div>
3529
3530<!-- _______________________________________________________________________ -->
3531<div class="doc_subsubsection">
3532 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3533</div>
3534<div class="doc_text">
3535
3536<h5>Syntax:</h5>
3537<pre>
3538 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3539</pre>
3540
3541<h5>Overview:</h5>
3542<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3543<tt>ty2</tt>.</p>
3544
3545
3546<h5>Arguments:</h5>
3547<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
3548<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3549also be of <a href="#t_integer">integer</a> type. The bit size of the
3550<tt>value</tt> must be smaller than the bit size of the destination type,
3551<tt>ty2</tt>.</p>
3552
3553<h5>Semantics:</h5>
3554<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
3555bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
3556
3557<p>When zero extending from i1, the result will always be either 0 or 1.</p>
3558
3559<h5>Example:</h5>
3560<pre>
3561 %X = zext i32 257 to i64 <i>; yields i64:257</i>
3562 %Y = zext i1 true to i32 <i>; yields i32:1</i>
3563</pre>
3564</div>
3565
3566<!-- _______________________________________________________________________ -->
3567<div class="doc_subsubsection">
3568 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3569</div>
3570<div class="doc_text">
3571
3572<h5>Syntax:</h5>
3573<pre>
3574 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3575</pre>
3576
3577<h5>Overview:</h5>
3578<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3579
3580<h5>Arguments:</h5>
3581<p>
3582The '<tt>sext</tt>' instruction takes a value to cast, which must be of
3583<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3584also be of <a href="#t_integer">integer</a> type. The bit size of the
3585<tt>value</tt> must be smaller than the bit size of the destination type,
3586<tt>ty2</tt>.</p>
3587
3588<h5>Semantics:</h5>
3589<p>
3590The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3591bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
3592the type <tt>ty2</tt>.</p>
3593
3594<p>When sign extending from i1, the extension always results in -1 or 0.</p>
3595
3596<h5>Example:</h5>
3597<pre>
3598 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
3599 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
3600</pre>
3601</div>
3602
3603<!-- _______________________________________________________________________ -->
3604<div class="doc_subsubsection">
3605 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3606</div>
3607
3608<div class="doc_text">
3609
3610<h5>Syntax:</h5>
3611
3612<pre>
3613 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3614</pre>
3615
3616<h5>Overview:</h5>
3617<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3618<tt>ty2</tt>.</p>
3619
3620
3621<h5>Arguments:</h5>
3622<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3623 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3624cast it to. The size of <tt>value</tt> must be larger than the size of
3625<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3626<i>no-op cast</i>.</p>
3627
3628<h5>Semantics:</h5>
3629<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3630<a href="#t_floating">floating point</a> type to a smaller
3631<a href="#t_floating">floating point</a> type. If the value cannot fit within
3632the destination type, <tt>ty2</tt>, then the results are undefined.</p>
3633
3634<h5>Example:</h5>
3635<pre>
3636 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3637 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3638</pre>
3639</div>
3640
3641<!-- _______________________________________________________________________ -->
3642<div class="doc_subsubsection">
3643 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3644</div>
3645<div class="doc_text">
3646
3647<h5>Syntax:</h5>
3648<pre>
3649 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3650</pre>
3651
3652<h5>Overview:</h5>
3653<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3654floating point value.</p>
3655
3656<h5>Arguments:</h5>
3657<p>The '<tt>fpext</tt>' instruction takes a
3658<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
3659and a <a href="#t_floating">floating point</a> type to cast it to. The source
3660type must be smaller than the destination type.</p>
3661
3662<h5>Semantics:</h5>
3663<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
3664<a href="#t_floating">floating point</a> type to a larger
3665<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
3666used to make a <i>no-op cast</i> because it always changes bits. Use
3667<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
3668
3669<h5>Example:</h5>
3670<pre>
3671 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3672 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3673</pre>
3674</div>
3675
3676<!-- _______________________________________________________________________ -->
3677<div class="doc_subsubsection">
3678 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
3679</div>
3680<div class="doc_text">
3681
3682<h5>Syntax:</h5>
3683<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3684 &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]3685</pre>
3686
3687<h5>Overview:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3688<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3689unsigned integer equivalent of type <tt>ty2</tt>.
3690</p>
3691
3692<h5>Arguments:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3693<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]3694scalar or vector <a href="#t_floating">floating point</a> value, and a type
3695to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3696type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3697vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3698
3699<h5>Semantics:</h5>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3700<p> The '<tt>fptoui</tt>' instruction converts its
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3701<a href="#t_floating">floating point</a> operand into the nearest (rounding
3702towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3703the results are undefined.</p>
3704
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3705<h5>Example:</h5>
3706<pre>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3707 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3708 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencere6adee82007-07-31 14:40:14 +0000[diff] [blame]3709 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3710</pre>
3711</div>
3712
3713<!-- _______________________________________________________________________ -->
3714<div class="doc_subsubsection">
3715 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
3716</div>
3717<div class="doc_text">
3718
3719<h5>Syntax:</h5>
3720<pre>
3721 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3722</pre>
3723
3724<h5>Overview:</h5>
3725<p>The '<tt>fptosi</tt>' instruction converts
3726<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
3727</p>
3728
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3729<h5>Arguments:</h5>
3730<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]3731scalar or vector <a href="#t_floating">floating point</a> value, and a type
3732to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3733type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3734vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3735
3736<h5>Semantics:</h5>
3737<p>The '<tt>fptosi</tt>' instruction converts its
3738<a href="#t_floating">floating point</a> operand into the nearest (rounding
3739towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3740the results are undefined.</p>
3741
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3742<h5>Example:</h5>
3743<pre>
3744 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner681f1e82007-09-22 03:17:52 +0000[diff] [blame]3745 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3746 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
3747</pre>
3748</div>
3749
3750<!-- _______________________________________________________________________ -->
3751<div class="doc_subsubsection">
3752 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
3753</div>
3754<div class="doc_text">
3755
3756<h5>Syntax:</h5>
3757<pre>
3758 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3759</pre>
3760
3761<h5>Overview:</h5>
3762<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
3763integer and converts that value to the <tt>ty2</tt> type.</p>
3764
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3765<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3766<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
3767scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3768to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3769type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3770floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3771
3772<h5>Semantics:</h5>
3773<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
3774integer quantity and converts it to the corresponding floating point value. If
3775the value cannot fit in the floating point value, the results are undefined.</p>
3776
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3777<h5>Example:</h5>
3778<pre>
3779 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3780 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3781</pre>
3782</div>
3783
3784<!-- _______________________________________________________________________ -->
3785<div class="doc_subsubsection">
3786 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
3787</div>
3788<div class="doc_text">
3789
3790<h5>Syntax:</h5>
3791<pre>
3792 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3793</pre>
3794
3795<h5>Overview:</h5>
3796<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
3797integer and converts that value to the <tt>ty2</tt> type.</p>
3798
3799<h5>Arguments:</h5>
Nate Begeman78246ca2007-11-17 03:58:34 +0000[diff] [blame]3800<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
3801scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
3802to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
3803type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
3804floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3805
3806<h5>Semantics:</h5>
3807<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
3808integer quantity and converts it to the corresponding floating point value. If
3809the value cannot fit in the floating point value, the results are undefined.</p>
3810
3811<h5>Example:</h5>
3812<pre>
3813 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3814 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3815</pre>
3816</div>
3817
3818<!-- _______________________________________________________________________ -->
3819<div class="doc_subsubsection">
3820 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3821</div>
3822<div class="doc_text">
3823
3824<h5>Syntax:</h5>
3825<pre>
3826 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3827</pre>
3828
3829<h5>Overview:</h5>
3830<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3831the integer type <tt>ty2</tt>.</p>
3832
3833<h5>Arguments:</h5>
3834<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3835must 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]3836<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]3837
3838<h5>Semantics:</h5>
3839<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3840<tt>ty2</tt> by interpreting the pointer value as an integer and either
3841truncating or zero extending that value to the size of the integer type. If
3842<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3843<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3844are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3845change.</p>
3846
3847<h5>Example:</h5>
3848<pre>
3849 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3850 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
3851</pre>
3852</div>
3853
3854<!-- _______________________________________________________________________ -->
3855<div class="doc_subsubsection">
3856 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3857</div>
3858<div class="doc_text">
3859
3860<h5>Syntax:</h5>
3861<pre>
3862 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3863</pre>
3864
3865<h5>Overview:</h5>
3866<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3867a pointer type, <tt>ty2</tt>.</p>
3868
3869<h5>Arguments:</h5>
3870<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
3871value to cast, and a type to cast it to, which must be a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3872<a href="#t_pointer">pointer</a> type.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3873
3874<h5>Semantics:</h5>
3875<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3876<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3877the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3878size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3879the size of a pointer then a zero extension is done. If they are the same size,
3880nothing is done (<i>no-op cast</i>).</p>
3881
3882<h5>Example:</h5>
3883<pre>
3884 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3885 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3886 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
3887</pre>
3888</div>
3889
3890<!-- _______________________________________________________________________ -->
3891<div class="doc_subsubsection">
3892 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
3893</div>
3894<div class="doc_text">
3895
3896<h5>Syntax:</h5>
3897<pre>
3898 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3899</pre>
3900
3901<h5>Overview:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3902
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3903<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3904<tt>ty2</tt> without changing any bits.</p>
3905
3906<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3907
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3908<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohman7305fa02008-09-08 16:45:59 +0000[diff] [blame]3909a non-aggregate first class value, and a type to cast it to, which must also be
3910a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
3911<tt>value</tt>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3912and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]3913type is a pointer, the destination type must also be a pointer. This
3914instruction supports bitwise conversion of vectors to integers and to vectors
3915of other types (as long as they have the same size).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3916
3917<h5>Semantics:</h5>
3918<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
3919<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3920this conversion. The conversion is done as if the <tt>value</tt> had been
3921stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3922converted to other pointer types with this instruction. To convert pointers to
3923other types, use the <a href="#i_inttoptr">inttoptr</a> or
3924<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
3925
3926<h5>Example:</h5>
3927<pre>
3928 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3929 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3930 %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]3931</pre>
3932</div>
3933
3934<!-- ======================================================================= -->
3935<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3936<div class="doc_text">
3937<p>The instructions in this category are the "miscellaneous"
3938instructions, which defy better classification.</p>
3939</div>
3940
3941<!-- _______________________________________________________________________ -->
3942<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3943</div>
3944<div class="doc_text">
3945<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3946<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]3947</pre>
3948<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3949<p>The '<tt>icmp</tt>' instruction returns a boolean value or
3950a vector of boolean values based on comparison
3951of its two integer, integer vector, or pointer operands.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3952<h5>Arguments:</h5>
3953<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3954the condition code indicating the kind of comparison to perform. It is not
3955a value, just a keyword. The possible condition code are:
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3956</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3957<ol>
3958 <li><tt>eq</tt>: equal</li>
3959 <li><tt>ne</tt>: not equal </li>
3960 <li><tt>ugt</tt>: unsigned greater than</li>
3961 <li><tt>uge</tt>: unsigned greater or equal</li>
3962 <li><tt>ult</tt>: unsigned less than</li>
3963 <li><tt>ule</tt>: unsigned less or equal</li>
3964 <li><tt>sgt</tt>: signed greater than</li>
3965 <li><tt>sge</tt>: signed greater or equal</li>
3966 <li><tt>slt</tt>: signed less than</li>
3967 <li><tt>sle</tt>: signed less or equal</li>
3968</ol>
3969<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3970<a href="#t_pointer">pointer</a>
3971or integer <a href="#t_vector">vector</a> typed.
3972They must also be identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3973<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3974<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]3975the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]3976yields 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]3977</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3978<ol>
3979 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3980 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3981 </li>
3982 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]3983 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3984 <li><tt>ugt</tt>: interprets the operands as unsigned 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>uge</tt>: interprets the operands as unsigned 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>ult</tt>: interprets the operands as unsigned 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>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3991 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3992 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3993 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3994 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3995 <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]3996 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3997 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]3998 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]3999 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4000</ol>
4001<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
4002values are compared as if they were integers.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4003<p>If the operands are integer vectors, then they are compared
4004element by element. The result is an <tt>i1</tt> vector with
4005the same number of elements as the values being compared.
4006Otherwise, the result is an <tt>i1</tt>.
4007</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4008
4009<h5>Example:</h5>
4010<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4011 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4012 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4013 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4014 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4015 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
4016</pre>
4017</div>
4018
4019<!-- _______________________________________________________________________ -->
4020<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4021</div>
4022<div class="doc_text">
4023<h5>Syntax:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4024<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]4025</pre>
4026<h5>Overview:</h5>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4027<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4028or vector of boolean values based on comparison
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4029of its operands.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4030<p>
4031If the operands are floating point scalars, then the result
4032type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4033</p>
4034<p>If the operands are floating point vectors, then the result type
4035is a vector of boolean with the same number of elements as the
4036operands being compared.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4037<h5>Arguments:</h5>
4038<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
4039the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4040a value, just a keyword. The possible condition code are:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4041<ol>
4042 <li><tt>false</tt>: no comparison, always returns false</li>
4043 <li><tt>oeq</tt>: ordered and equal</li>
4044 <li><tt>ogt</tt>: ordered and greater than </li>
4045 <li><tt>oge</tt>: ordered and greater than or equal</li>
4046 <li><tt>olt</tt>: ordered and less than </li>
4047 <li><tt>ole</tt>: ordered and less than or equal</li>
4048 <li><tt>one</tt>: ordered and not equal</li>
4049 <li><tt>ord</tt>: ordered (no nans)</li>
4050 <li><tt>ueq</tt>: unordered or equal</li>
4051 <li><tt>ugt</tt>: unordered or greater than </li>
4052 <li><tt>uge</tt>: unordered or greater than or equal</li>
4053 <li><tt>ult</tt>: unordered or less than </li>
4054 <li><tt>ule</tt>: unordered or less than or equal</li>
4055 <li><tt>une</tt>: unordered or not equal</li>
4056 <li><tt>uno</tt>: unordered (either nans)</li>
4057 <li><tt>true</tt>: no comparison, always returns true</li>
4058</ol>
4059<p><i>Ordered</i> means that neither operand is a QNAN while
4060<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4061<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4062either a <a href="#t_floating">floating point</a> type
4063or a <a href="#t_vector">vector</a> of floating point type.
4064They must have identical types.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4065<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4066<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4067according to the condition code given as <tt>cond</tt>.
4068If the operands are vectors, then the vectors are compared
4069element by element.
4070Each comparison performed
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4071always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4072<ol>
4073 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
4074 <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]4075 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4076 <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]4077 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4078 <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]4079 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4080 <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]4081 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4082 <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]4083 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4084 <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]4085 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4086 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4087 <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]4088 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4089 <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]4090 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4091 <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]4092 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4093 <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]4094 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4095 <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]4096 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4097 <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]4098 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4099 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
4100 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4101</ol>
4102
4103<h5>Example:</h5>
4104<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]4105 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4106 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4107 &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]4108</pre>
4109</div>
4110
4111<!-- _______________________________________________________________________ -->
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4112<div class="doc_subsubsection">
4113 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4114</div>
4115<div class="doc_text">
4116<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4117<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]4118</pre>
4119<h5>Overview:</h5>
4120<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4121element-wise comparison of its two integer vector operands.</p>
4122<h5>Arguments:</h5>
4123<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4124the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4125a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4126<ol>
4127 <li><tt>eq</tt>: equal</li>
4128 <li><tt>ne</tt>: not equal </li>
4129 <li><tt>ugt</tt>: unsigned greater than</li>
4130 <li><tt>uge</tt>: unsigned greater or equal</li>
4131 <li><tt>ult</tt>: unsigned less than</li>
4132 <li><tt>ule</tt>: unsigned less or equal</li>
4133 <li><tt>sgt</tt>: signed greater than</li>
4134 <li><tt>sge</tt>: signed greater or equal</li>
4135 <li><tt>slt</tt>: signed less than</li>
4136 <li><tt>sle</tt>: signed less or equal</li>
4137</ol>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4138<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4139<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4140<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4141<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4142according to the condition code given as <tt>cond</tt>. The comparison yields a
4143<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4144identical type as the values being compared. The most significant bit in each
4145element is 1 if the element-wise comparison evaluates to true, and is 0
4146otherwise. All other bits of the result are undefined. The condition codes
4147are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4148instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4149
4150<h5>Example:</h5>
4151<pre>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4152 &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>
4153 &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]4154</pre>
4155</div>
4156
4157<!-- _______________________________________________________________________ -->
4158<div class="doc_subsubsection">
4159 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4160</div>
4161<div class="doc_text">
4162<h5>Syntax:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4163<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]4164<h5>Overview:</h5>
4165<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4166element-wise comparison of its two floating point vector operands. The output
4167elements have the same width as the input elements.</p>
4168<h5>Arguments:</h5>
4169<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4170the condition code indicating the kind of comparison to perform. It is not
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4171a value, just a keyword. The possible condition code are:</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4172<ol>
4173 <li><tt>false</tt>: no comparison, always returns false</li>
4174 <li><tt>oeq</tt>: ordered and equal</li>
4175 <li><tt>ogt</tt>: ordered and greater than </li>
4176 <li><tt>oge</tt>: ordered and greater than or equal</li>
4177 <li><tt>olt</tt>: ordered and less than </li>
4178 <li><tt>ole</tt>: ordered and less than or equal</li>
4179 <li><tt>one</tt>: ordered and not equal</li>
4180 <li><tt>ord</tt>: ordered (no nans)</li>
4181 <li><tt>ueq</tt>: unordered or equal</li>
4182 <li><tt>ugt</tt>: unordered or greater than </li>
4183 <li><tt>uge</tt>: unordered or greater than or equal</li>
4184 <li><tt>ult</tt>: unordered or less than </li>
4185 <li><tt>ule</tt>: unordered or less than or equal</li>
4186 <li><tt>une</tt>: unordered or not equal</li>
4187 <li><tt>uno</tt>: unordered (either nans)</li>
4188 <li><tt>true</tt>: no comparison, always returns true</li>
4189</ol>
4190<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4191<a href="#t_floating">floating point</a> typed. They must also be identical
4192types.</p>
4193<h5>Semantics:</h5>
Gabor Greifd9068fe2008-08-07 21:46:00 +0000[diff] [blame]4194<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4195according to the condition code given as <tt>cond</tt>. The comparison yields a
4196<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4197an identical number of elements as the values being compared, and each element
4198having identical with to the width of the floating point elements. The most
4199significant bit in each element is 1 if the element-wise comparison evaluates to
4200true, and is 0 otherwise. All other bits of the result are undefined. The
4201condition codes are evaluated identically to the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4202<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begeman646fa482008-05-12 19:01:56 +0000[diff] [blame]4203
4204<h5>Example:</h5>
4205<pre>
Chris Lattner1e5c5cd02008-10-13 16:55:18 +0000[diff] [blame]4206 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4207 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4208
4209 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4210 &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]4211</pre>
4212</div>
4213
4214<!-- _______________________________________________________________________ -->
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4215<div class="doc_subsubsection">
4216 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4217</div>
4218
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4219<div class="doc_text">
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4220
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4221<h5>Syntax:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4222
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4223<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4224<h5>Overview:</h5>
4225<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4226the SSA graph representing the function.</p>
4227<h5>Arguments:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4228
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4229<p>The type of the incoming values is specified with the first type
4230field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4231as arguments, with one pair for each predecessor basic block of the
4232current block. Only values of <a href="#t_firstclass">first class</a>
4233type may be used as the value arguments to the PHI node. Only labels
4234may be used as the label arguments.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4235
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4236<p>There must be no non-phi instructions between the start of a basic
4237block and the PHI instructions: i.e. PHI instructions must be first in
4238a basic block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4239
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4240<h5>Semantics:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4241
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4242<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4243specified by the pair corresponding to the predecessor basic block that executed
4244just prior to the current block.</p>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4245
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4246<h5>Example:</h5>
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4247<pre>
4248Loop: ; Infinite loop that counts from 0 on up...
4249 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4250 %nextindvar = add i32 %indvar, 1
4251 br label %Loop
4252</pre>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4253</div>
4254
4255<!-- _______________________________________________________________________ -->
4256<div class="doc_subsubsection">
4257 <a name="i_select">'<tt>select</tt>' Instruction</a>
4258</div>
4259
4260<div class="doc_text">
4261
4262<h5>Syntax:</h5>
4263
4264<pre>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4265 &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>
4266
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4267 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4268</pre>
4269
4270<h5>Overview:</h5>
4271
4272<p>
4273The '<tt>select</tt>' instruction is used to choose one value based on a
4274condition, without branching.
4275</p>
4276
4277
4278<h5>Arguments:</h5>
4279
4280<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4281The '<tt>select</tt>' instruction requires an 'i1' value or
4282a vector of 'i1' values indicating the
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4283condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4284type. If the val1/val2 are vectors and
4285the condition is a scalar, then entire vectors are selected, not
Chris Lattner6704c212008-05-20 20:48:21 +0000[diff] [blame]4286individual elements.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4287</p>
4288
4289<h5>Semantics:</h5>
4290
4291<p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4292If 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]4293value argument; otherwise, it returns the second value argument.
4294</p>
Dan Gohmanb60ca3c2008-09-09 01:02:47 +0000[diff] [blame]4295<p>
4296If the condition is a vector of i1, then the value arguments must
4297be vectors of the same size, and the selection is done element
4298by element.
4299</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4300
4301<h5>Example:</h5>
4302
4303<pre>
4304 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
4305</pre>
4306</div>
4307
4308
4309<!-- _______________________________________________________________________ -->
4310<div class="doc_subsubsection">
4311 <a name="i_call">'<tt>call</tt>' Instruction</a>
4312</div>
4313
4314<div class="doc_text">
4315
4316<h5>Syntax:</h5>
4317<pre>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4318 &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]4319</pre>
4320
4321<h5>Overview:</h5>
4322
4323<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
4324
4325<h5>Arguments:</h5>
4326
4327<p>This instruction requires several arguments:</p>
4328
4329<ol>
4330 <li>
4331 <p>The optional "tail" marker indicates whether the callee function accesses
4332 any allocas or varargs in the caller. If the "tail" marker is present, the
4333 function call is eligible for tail call optimization. Note that calls may
4334 be marked "tail" even if they do not occur before a <a
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4335 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4336 </li>
4337 <li>
4338 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
4339 convention</a> the call should use. If none is specified, the call defaults
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4340 to using C calling conventions.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4341 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4342
4343 <li>
4344 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4345 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4346 and '<tt>inreg</tt>' attributes are valid here.</p>
4347 </li>
4348
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4349 <li>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4350 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4351 the type of the return value. Functions that return no value are marked
4352 <tt><a href="#t_void">void</a></tt>.</p>
4353 </li>
4354 <li>
4355 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4356 value being invoked. The argument types must match the types implied by
4357 this signature. This type can be omitted if the function is not varargs
4358 and if the function type does not return a pointer to a function.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4359 </li>
4360 <li>
4361 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4362 be invoked. In most cases, this is a direct function invocation, but
4363 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
4364 to function value.</p>
4365 </li>
4366 <li>
4367 <p>'<tt>function args</tt>': argument list whose types match the
4368 function signature argument types. All arguments must be of
4369 <a href="#t_firstclass">first class</a> type. If the function signature
4370 indicates the function accepts a variable number of arguments, the extra
4371 arguments can be specified.</p>
4372 </li>
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4373 <li>
Devang Pateld0bfcc72008-10-07 17:48:33 +0000[diff] [blame]4374 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4375 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4376 '<tt>readnone</tt>' attributes are valid here.</p>
4377 </li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4378</ol>
4379
4380<h5>Semantics:</h5>
4381
4382<p>The '<tt>call</tt>' instruction is used to cause control flow to
4383transfer to a specified function, with its incoming arguments bound to
4384the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4385instruction in the called function, control flow continues with the
4386instruction after the function call, and the return value of the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4387function is bound to the result argument.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4388
4389<h5>Example:</h5>
4390
4391<pre>
Nick Lewycky93082fc2007-09-08 13:57:50 +0000[diff] [blame]4392 %retval = call i32 @test(i32 %argc)
Chris Lattner5e893ef2008-03-21 17:24:17 +0000[diff] [blame]4393 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4394 %X = tail call i32 @foo() <i>; yields i32</i>
4395 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4396 call void %foo(i8 97 signext)
Devang Patela3cc5372008-03-10 20:49:15 +0000[diff] [blame]4397
4398 %struct.A = type { i32, i8 }
Devang Patelac2fc272008-10-06 18:50:38 +0000[diff] [blame]4399 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman3e700032008-10-04 19:00:07 +0000[diff] [blame]4400 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4401 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattnerac454b32008-10-08 06:26:11 +0000[diff] [blame]4402 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman2c4e05a2008-10-07 10:03:45 +0000[diff] [blame]4403 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4404</pre>
4405
4406</div>
4407
4408<!-- _______________________________________________________________________ -->
4409<div class="doc_subsubsection">
4410 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
4411</div>
4412
4413<div class="doc_text">
4414
4415<h5>Syntax:</h5>
4416
4417<pre>
4418 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
4419</pre>
4420
4421<h5>Overview:</h5>
4422
4423<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
4424the "variable argument" area of a function call. It is used to implement the
4425<tt>va_arg</tt> macro in C.</p>
4426
4427<h5>Arguments:</h5>
4428
4429<p>This instruction takes a <tt>va_list*</tt> value and the type of
4430the argument. It returns a value of the specified argument type and
4431increments the <tt>va_list</tt> to point to the next argument. The
4432actual type of <tt>va_list</tt> is target specific.</p>
4433
4434<h5>Semantics:</h5>
4435
4436<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4437type from the specified <tt>va_list</tt> and causes the
4438<tt>va_list</tt> to point to the next argument. For more information,
4439see the variable argument handling <a href="#int_varargs">Intrinsic
4440Functions</a>.</p>
4441
4442<p>It is legal for this instruction to be called in a function which does not
4443take a variable number of arguments, for example, the <tt>vfprintf</tt>
4444function.</p>
4445
4446<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
4447href="#intrinsics">intrinsic function</a> because it takes a type as an
4448argument.</p>
4449
4450<h5>Example:</h5>
4451
4452<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4453
4454</div>
4455
4456<!-- *********************************************************************** -->
4457<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4458<!-- *********************************************************************** -->
4459
4460<div class="doc_text">
4461
4462<p>LLVM supports the notion of an "intrinsic function". These functions have
4463well known names and semantics and are required to follow certain restrictions.
4464Overall, these intrinsics represent an extension mechanism for the LLVM
4465language that does not require changing all of the transformations in LLVM when
4466adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
4467
4468<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
4469prefix is reserved in LLVM for intrinsic names; thus, function names may not
4470begin with this prefix. Intrinsic functions must always be external functions:
4471you cannot define the body of intrinsic functions. Intrinsic functions may
4472only be used in call or invoke instructions: it is illegal to take the address
4473of an intrinsic function. Additionally, because intrinsic functions are part
4474of the LLVM language, it is required if any are added that they be documented
4475here.</p>
4476
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4477<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4478a family of functions that perform the same operation but on different data
4479types. Because LLVM can represent over 8 million different integer types,
4480overloading is used commonly to allow an intrinsic function to operate on any
4481integer type. One or more of the argument types or the result type can be
4482overloaded to accept any integer type. Argument types may also be defined as
4483exactly matching a previous argument's type or the result type. This allows an
4484intrinsic function which accepts multiple arguments, but needs all of them to
4485be of the same type, to only be overloaded with respect to a single argument or
4486the result.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4487
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]4488<p>Overloaded intrinsics will have the names of its overloaded argument types
4489encoded into its function name, each preceded by a period. Only those types
4490which are overloaded result in a name suffix. Arguments whose type is matched
4491against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4492take an integer of any width and returns an integer of exactly the same integer
4493width. This leads to a family of functions such as
4494<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4495Only one type, the return type, is overloaded, and only one type suffix is
4496required. Because the argument's type is matched against the return type, it
4497does not require its own name suffix.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4498
4499<p>To learn how to add an intrinsic function, please see the
4500<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
4501</p>
4502
4503</div>
4504
4505<!-- ======================================================================= -->
4506<div class="doc_subsection">
4507 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4508</div>
4509
4510<div class="doc_text">
4511
4512<p>Variable argument support is defined in LLVM with the <a
4513 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
4514intrinsic functions. These functions are related to the similarly
4515named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
4516
4517<p>All of these functions operate on arguments that use a
4518target-specific value type "<tt>va_list</tt>". The LLVM assembly
4519language reference manual does not define what this type is, so all
4520transformations should be prepared to handle these functions regardless of
4521the type used.</p>
4522
4523<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
4524instruction and the variable argument handling intrinsic functions are
4525used.</p>
4526
4527<div class="doc_code">
4528<pre>
4529define i32 @test(i32 %X, ...) {
4530 ; Initialize variable argument processing
4531 %ap = alloca i8*
4532 %ap2 = bitcast i8** %ap to i8*
4533 call void @llvm.va_start(i8* %ap2)
4534
4535 ; Read a single integer argument
4536 %tmp = va_arg i8** %ap, i32
4537
4538 ; Demonstrate usage of llvm.va_copy and llvm.va_end
4539 %aq = alloca i8*
4540 %aq2 = bitcast i8** %aq to i8*
4541 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
4542 call void @llvm.va_end(i8* %aq2)
4543
4544 ; Stop processing of arguments.
4545 call void @llvm.va_end(i8* %ap2)
4546 ret i32 %tmp
4547}
4548
4549declare void @llvm.va_start(i8*)
4550declare void @llvm.va_copy(i8*, i8*)
4551declare void @llvm.va_end(i8*)
4552</pre>
4553</div>
4554
4555</div>
4556
4557<!-- _______________________________________________________________________ -->
4558<div class="doc_subsubsection">
4559 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
4560</div>
4561
4562
4563<div class="doc_text">
4564<h5>Syntax:</h5>
4565<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
4566<h5>Overview:</h5>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4567<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4568<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4569href="#i_va_arg">va_arg</a></tt>.</p>
4570
4571<h5>Arguments:</h5>
4572
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4573<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]4574
4575<h5>Semantics:</h5>
4576
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]4577<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]4578macro available in C. In a target-dependent way, it initializes the
4579<tt>va_list</tt> element to which the argument points, so that the next call to
4580<tt>va_arg</tt> will produce the first variable argument passed to the function.
4581Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
4582last argument of the function as the compiler can figure that out.</p>
4583
4584</div>
4585
4586<!-- _______________________________________________________________________ -->
4587<div class="doc_subsubsection">
4588 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
4589</div>
4590
4591<div class="doc_text">
4592<h5>Syntax:</h5>
4593<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
4594<h5>Overview:</h5>
4595
4596<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
4597which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
4598or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
4599
4600<h5>Arguments:</h5>
4601
4602<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
4603
4604<h5>Semantics:</h5>
4605
4606<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
4607macro available in C. In a target-dependent way, it destroys the
4608<tt>va_list</tt> element to which the argument points. Calls to <a
4609href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4610<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4611<tt>llvm.va_end</tt>.</p>
4612
4613</div>
4614
4615<!-- _______________________________________________________________________ -->
4616<div class="doc_subsubsection">
4617 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
4618</div>
4619
4620<div class="doc_text">
4621
4622<h5>Syntax:</h5>
4623
4624<pre>
4625 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
4626</pre>
4627
4628<h5>Overview:</h5>
4629
4630<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4631from the source argument list to the destination argument list.</p>
4632
4633<h5>Arguments:</h5>
4634
4635<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
4636The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
4637
4638
4639<h5>Semantics:</h5>
4640
4641<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4642macro available in C. In a target-dependent way, it copies the source
4643<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4644intrinsic is necessary because the <tt><a href="#int_va_start">
4645llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4646example, memory allocation.</p>
4647
4648</div>
4649
4650<!-- ======================================================================= -->
4651<div class="doc_subsection">
4652 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4653</div>
4654
4655<div class="doc_text">
4656
4657<p>
4658LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]4659Collection</a> (GC) requires the implementation and generation of these
4660intrinsics.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4661These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
4662stack</a>, as well as garbage collector implementations that require <a
4663href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
4664Front-ends for type-safe garbage collected languages should generate these
4665intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4666href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4667</p>
Christopher Lambcfe00962007-12-17 01:00:21 +0000[diff] [blame]4668
4669<p>The garbage collection intrinsics only operate on objects in the generic
4670 address space (address space zero).</p>
4671
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4672</div>
4673
4674<!-- _______________________________________________________________________ -->
4675<div class="doc_subsubsection">
4676 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
4677</div>
4678
4679<div class="doc_text">
4680
4681<h5>Syntax:</h5>
4682
4683<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4684 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4685</pre>
4686
4687<h5>Overview:</h5>
4688
4689<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
4690the code generator, and allows some metadata to be associated with it.</p>
4691
4692<h5>Arguments:</h5>
4693
4694<p>The first argument specifies the address of a stack object that contains the
4695root pointer. The second pointer (which must be either a constant or a global
4696value address) contains the meta-data to be associated with the root.</p>
4697
4698<h5>Semantics:</h5>
4699
Chris Lattnera7d94ba2008-04-24 05:59:56 +0000[diff] [blame]4700<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]4701location. At compile-time, the code generator generates information to allow
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4702the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4703intrinsic may only be used in a function which <a href="#gc">specifies a GC
4704algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4705
4706</div>
4707
4708
4709<!-- _______________________________________________________________________ -->
4710<div class="doc_subsubsection">
4711 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
4712</div>
4713
4714<div class="doc_text">
4715
4716<h5>Syntax:</h5>
4717
4718<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4719 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4720</pre>
4721
4722<h5>Overview:</h5>
4723
4724<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4725locations, allowing garbage collector implementations that require read
4726barriers.</p>
4727
4728<h5>Arguments:</h5>
4729
4730<p>The second argument is the address to read from, which should be an address
4731allocated from the garbage collector. The first object is a pointer to the
4732start of the referenced object, if needed by the language runtime (otherwise
4733null).</p>
4734
4735<h5>Semantics:</h5>
4736
4737<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4738instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4739garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4740may only be used in a function which <a href="#gc">specifies a GC
4741algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4742
4743</div>
4744
4745
4746<!-- _______________________________________________________________________ -->
4747<div class="doc_subsubsection">
4748 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
4749</div>
4750
4751<div class="doc_text">
4752
4753<h5>Syntax:</h5>
4754
4755<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4756 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4757</pre>
4758
4759<h5>Overview:</h5>
4760
4761<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
4762locations, allowing garbage collector implementations that require write
4763barriers (such as generational or reference counting collectors).</p>
4764
4765<h5>Arguments:</h5>
4766
4767<p>The first argument is the reference to store, the second is the start of the
4768object to store it to, and the third is the address of the field of Obj to
4769store to. If the runtime does not require a pointer to the object, Obj may be
4770null.</p>
4771
4772<h5>Semantics:</h5>
4773
4774<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
4775instruction, but may be replaced with substantially more complex code by the
Gordon Henriksen40393542007-12-25 02:31:26 +0000[diff] [blame]4776garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
4777may only be used in a function which <a href="#gc">specifies a GC
4778algorithm</a>.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4779
4780</div>
4781
4782
4783
4784<!-- ======================================================================= -->
4785<div class="doc_subsection">
4786 <a name="int_codegen">Code Generator Intrinsics</a>
4787</div>
4788
4789<div class="doc_text">
4790<p>
4791These intrinsics are provided by LLVM to expose special features that may only
4792be implemented with code generator support.
4793</p>
4794
4795</div>
4796
4797<!-- _______________________________________________________________________ -->
4798<div class="doc_subsubsection">
4799 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
4800</div>
4801
4802<div class="doc_text">
4803
4804<h5>Syntax:</h5>
4805<pre>
4806 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
4807</pre>
4808
4809<h5>Overview:</h5>
4810
4811<p>
4812The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4813target-specific value indicating the return address of the current function
4814or one of its callers.
4815</p>
4816
4817<h5>Arguments:</h5>
4818
4819<p>
4820The argument to this intrinsic indicates which function to return the address
4821for. Zero indicates the calling function, one indicates its caller, etc. The
4822argument is <b>required</b> to be a constant integer value.
4823</p>
4824
4825<h5>Semantics:</h5>
4826
4827<p>
4828The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4829the return address of the specified call frame, or zero if it cannot be
4830identified. The value returned by this intrinsic is likely to be incorrect or 0
4831for arguments other than zero, so it should only be used for debugging purposes.
4832</p>
4833
4834<p>
4835Note that calling this intrinsic does not prevent function inlining or other
4836aggressive transformations, so the value returned may not be that of the obvious
4837source-language caller.
4838</p>
4839</div>
4840
4841
4842<!-- _______________________________________________________________________ -->
4843<div class="doc_subsubsection">
4844 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
4845</div>
4846
4847<div class="doc_text">
4848
4849<h5>Syntax:</h5>
4850<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4851 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4852</pre>
4853
4854<h5>Overview:</h5>
4855
4856<p>
4857The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4858target-specific frame pointer value for the specified stack frame.
4859</p>
4860
4861<h5>Arguments:</h5>
4862
4863<p>
4864The argument to this intrinsic indicates which function to return the frame
4865pointer for. Zero indicates the calling function, one indicates its caller,
4866etc. The argument is <b>required</b> to be a constant integer value.
4867</p>
4868
4869<h5>Semantics:</h5>
4870
4871<p>
4872The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4873the frame address of the specified call frame, or zero if it cannot be
4874identified. The value returned by this intrinsic is likely to be incorrect or 0
4875for arguments other than zero, so it should only be used for debugging purposes.
4876</p>
4877
4878<p>
4879Note that calling this intrinsic does not prevent function inlining or other
4880aggressive transformations, so the value returned may not be that of the obvious
4881source-language caller.
4882</p>
4883</div>
4884
4885<!-- _______________________________________________________________________ -->
4886<div class="doc_subsubsection">
4887 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
4888</div>
4889
4890<div class="doc_text">
4891
4892<h5>Syntax:</h5>
4893<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4894 declare i8 *@llvm.stacksave()
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]4895</pre>
4896
4897<h5>Overview:</h5>
4898
4899<p>
4900The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
4901the function stack, for use with <a href="#int_stackrestore">
4902<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4903features like scoped automatic variable sized arrays in C99.
4904</p>
4905
4906<h5>Semantics:</h5>
4907
4908<p>
4909This intrinsic returns a opaque pointer value that can be passed to <a
4910href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
4911<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4912<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4913state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4914practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4915that were allocated after the <tt>llvm.stacksave</tt> was executed.
4916</p>
4917
4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
4922 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
4923</div>
4924
4925<div class="doc_text">
4926
4927<h5>Syntax:</h5>
4928<pre>
4929 declare void @llvm.stackrestore(i8 * %ptr)
4930</pre>
4931
4932<h5>Overview:</h5>
4933
4934<p>
4935The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4936the function stack to the state it was in when the corresponding <a
4937href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
4938useful for implementing language features like scoped automatic variable sized
4939arrays in C99.
4940</p>
4941
4942<h5>Semantics:</h5>
4943
4944<p>
4945See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
4946</p>
4947
4948</div>
4949
4950
4951<!-- _______________________________________________________________________ -->
4952<div class="doc_subsubsection">
4953 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
4954</div>
4955
4956<div class="doc_text">
4957
4958<h5>Syntax:</h5>
4959<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]4960 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]4961</pre>
4962
4963<h5>Overview:</h5>
4964
4965
4966<p>
4967The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
4968a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4969no
4970effect on the behavior of the program but can change its performance
4971characteristics.
4972</p>
4973
4974<h5>Arguments:</h5>
4975
4976<p>
4977<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4978determining if the fetch should be for a read (0) or write (1), and
4979<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
4980locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
4981<tt>locality</tt> arguments must be constant integers.
4982</p>
4983
4984<h5>Semantics:</h5>
4985
4986<p>
4987This intrinsic does not modify the behavior of the program. In particular,
4988prefetches cannot trap and do not produce a value. On targets that support this
4989intrinsic, the prefetch can provide hints to the processor cache for better
4990performance.
4991</p>
4992
4993</div>
4994
4995<!-- _______________________________________________________________________ -->
4996<div class="doc_subsubsection">
4997 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
4998</div>
4999
5000<div class="doc_text">
5001
5002<h5>Syntax:</h5>
5003<pre>
Chris Lattner38bd5dd2007-09-21 17:30:40 +0000[diff] [blame]5004 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5005</pre>
5006
5007<h5>Overview:</h5>
5008
5009
5010<p>
5011The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5012(PC) in a region of
5013code to simulators and other tools. The method is target specific, but it is
5014expected that the marker will use exported symbols to transmit the PC of the
5015marker.
5016The marker makes no guarantees that it will remain with any specific instruction
5017after optimizations. It is possible that the presence of a marker will inhibit
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5018optimizations. The intended use is to be inserted after optimizations to allow
5019correlations of simulation runs.
5020</p>
5021
5022<h5>Arguments:</h5>
5023
5024<p>
5025<tt>id</tt> is a numerical id identifying the marker.
5026</p>
5027
5028<h5>Semantics:</h5>
5029
5030<p>
5031This intrinsic does not modify the behavior of the program. Backends that do not
5032support this intrinisic may ignore it.
5033</p>
5034
5035</div>
5036
5037<!-- _______________________________________________________________________ -->
5038<div class="doc_subsubsection">
5039 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
5040</div>
5041
5042<div class="doc_text">
5043
5044<h5>Syntax:</h5>
5045<pre>
5046 declare i64 @llvm.readcyclecounter( )
5047</pre>
5048
5049<h5>Overview:</h5>
5050
5051
5052<p>
5053The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5054counter register (or similar low latency, high accuracy clocks) on those targets
5055that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5056As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5057should only be used for small timings.
5058</p>
5059
5060<h5>Semantics:</h5>
5061
5062<p>
5063When directly supported, reading the cycle counter should not modify any memory.
5064Implementations are allowed to either return a application specific value or a
5065system wide value. On backends without support, this is lowered to a constant 0.
5066</p>
5067
5068</div>
5069
5070<!-- ======================================================================= -->
5071<div class="doc_subsection">
5072 <a name="int_libc">Standard C Library Intrinsics</a>
5073</div>
5074
5075<div class="doc_text">
5076<p>
5077LLVM provides intrinsics for a few important standard C library functions.
5078These intrinsics allow source-language front-ends to pass information about the
5079alignment of the pointer arguments to the code generator, providing opportunity
5080for more efficient code generation.
5081</p>
5082
5083</div>
5084
5085<!-- _______________________________________________________________________ -->
5086<div class="doc_subsubsection">
5087 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
5088</div>
5089
5090<div class="doc_text">
5091
5092<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5093<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5094width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5095<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5096 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5097 i8 &lt;len&gt;, i32 &lt;align&gt;)
5098 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5099 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5100 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5101 i32 &lt;len&gt;, i32 &lt;align&gt;)
5102 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5103 i64 &lt;len&gt;, i32 &lt;align&gt;)
5104</pre>
5105
5106<h5>Overview:</h5>
5107
5108<p>
5109The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5110location to the destination location.
5111</p>
5112
5113<p>
5114Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5115intrinsics do not return a value, and takes an extra alignment argument.
5116</p>
5117
5118<h5>Arguments:</h5>
5119
5120<p>
5121The first argument is a pointer to the destination, the second is a pointer to
5122the source. The third argument is an integer argument
5123specifying the number of bytes to copy, and the fourth argument is the alignment
5124of the source and destination locations.
5125</p>
5126
5127<p>
5128If the call to this intrinisic has an alignment value that is not 0 or 1, then
5129the caller guarantees that both the source and destination pointers are aligned
5130to that boundary.
5131</p>
5132
5133<h5>Semantics:</h5>
5134
5135<p>
5136The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
5137location to the destination location, which are not allowed to overlap. It
5138copies "len" bytes of memory over. If the argument is known to be aligned to
5139some boundary, this can be specified as the fourth argument, otherwise it should
5140be set to 0 or 1.
5141</p>
5142</div>
5143
5144
5145<!-- _______________________________________________________________________ -->
5146<div class="doc_subsubsection">
5147 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
5148</div>
5149
5150<div class="doc_text">
5151
5152<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5153<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5154width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5155<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5156 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5157 i8 &lt;len&gt;, i32 &lt;align&gt;)
5158 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5159 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5160 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5161 i32 &lt;len&gt;, i32 &lt;align&gt;)
5162 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5163 i64 &lt;len&gt;, i32 &lt;align&gt;)
5164</pre>
5165
5166<h5>Overview:</h5>
5167
5168<p>
5169The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5170location to the destination location. It is similar to the
Chris Lattnerdba16ea2008-01-06 19:51:52 +0000[diff] [blame]5171'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5172</p>
5173
5174<p>
5175Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5176intrinsics do not return a value, and takes an extra alignment argument.
5177</p>
5178
5179<h5>Arguments:</h5>
5180
5181<p>
5182The first argument is a pointer to the destination, the second is a pointer to
5183the source. The third argument is an integer argument
5184specifying the number of bytes to copy, and the fourth argument is the alignment
5185of the source and destination locations.
5186</p>
5187
5188<p>
5189If the call to this intrinisic has an alignment value that is not 0 or 1, then
5190the caller guarantees that the source and destination pointers are aligned to
5191that boundary.
5192</p>
5193
5194<h5>Semantics:</h5>
5195
5196<p>
5197The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
5198location to the destination location, which may overlap. It
5199copies "len" bytes of memory over. If the argument is known to be aligned to
5200some boundary, this can be specified as the fourth argument, otherwise it should
5201be set to 0 or 1.
5202</p>
5203</div>
5204
5205
5206<!-- _______________________________________________________________________ -->
5207<div class="doc_subsubsection">
5208 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
5209</div>
5210
5211<div class="doc_text">
5212
5213<h5>Syntax:</h5>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5214<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5215width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5216<pre>
Chris Lattner82c2e432008-11-21 16:42:48 +0000[diff] [blame]5217 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5218 i8 &lt;len&gt;, i32 &lt;align&gt;)
5219 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5220 i16 &lt;len&gt;, i32 &lt;align&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5221 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5222 i32 &lt;len&gt;, i32 &lt;align&gt;)
5223 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5224 i64 &lt;len&gt;, i32 &lt;align&gt;)
5225</pre>
5226
5227<h5>Overview:</h5>
5228
5229<p>
5230The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
5231byte value.
5232</p>
5233
5234<p>
5235Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5236does not return a value, and takes an extra alignment argument.
5237</p>
5238
5239<h5>Arguments:</h5>
5240
5241<p>
5242The first argument is a pointer to the destination to fill, the second is the
5243byte value to fill it with, the third argument is an integer
5244argument specifying the number of bytes to fill, and the fourth argument is the
5245known alignment of destination location.
5246</p>
5247
5248<p>
5249If the call to this intrinisic has an alignment value that is not 0 or 1, then
5250the caller guarantees that the destination pointer is aligned to that boundary.
5251</p>
5252
5253<h5>Semantics:</h5>
5254
5255<p>
5256The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5257the
5258destination location. If the argument is known to be aligned to some boundary,
5259this can be specified as the fourth argument, otherwise it should be set to 0 or
52601.
5261</p>
5262</div>
5263
5264
5265<!-- _______________________________________________________________________ -->
5266<div class="doc_subsubsection">
5267 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
5268</div>
5269
5270<div class="doc_text">
5271
5272<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5273<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]5274floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5275types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5276<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5277 declare float @llvm.sqrt.f32(float %Val)
5278 declare double @llvm.sqrt.f64(double %Val)
5279 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5280 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5281 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5282</pre>
5283
5284<h5>Overview:</h5>
5285
5286<p>
5287The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5288returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5289<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattnerf914a002008-01-29 07:00:44 +0000[diff] [blame]5290negative numbers other than -0.0 (which allows for better optimization, because
5291there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5292defined to return -0.0 like IEEE sqrt.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5293</p>
5294
5295<h5>Arguments:</h5>
5296
5297<p>
5298The argument and return value are floating point numbers of the same type.
5299</p>
5300
5301<h5>Semantics:</h5>
5302
5303<p>
5304This function returns the sqrt of the specified operand if it is a nonnegative
5305floating point number.
5306</p>
5307</div>
5308
5309<!-- _______________________________________________________________________ -->
5310<div class="doc_subsubsection">
5311 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
5312</div>
5313
5314<div class="doc_text">
5315
5316<h5>Syntax:</h5>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5317<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]5318floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5319types however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5320<pre>
Dale Johannesenf9adbb62007-10-02 17:47:38 +0000[diff] [blame]5321 declare float @llvm.powi.f32(float %Val, i32 %power)
5322 declare double @llvm.powi.f64(double %Val, i32 %power)
5323 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5324 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5325 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5326</pre>
5327
5328<h5>Overview:</h5>
5329
5330<p>
5331The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5332specified (positive or negative) power. The order of evaluation of
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5333multiplications is not defined. When a vector of floating point type is
5334used, the second argument remains a scalar integer value.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5335</p>
5336
5337<h5>Arguments:</h5>
5338
5339<p>
5340The second argument is an integer power, and the first is a value to raise to
5341that power.
5342</p>
5343
5344<h5>Semantics:</h5>
5345
5346<p>
5347This function returns the first value raised to the second power with an
5348unspecified sequence of rounding operations.</p>
5349</div>
5350
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5351<!-- _______________________________________________________________________ -->
5352<div class="doc_subsubsection">
5353 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5354</div>
5355
5356<div class="doc_text">
5357
5358<h5>Syntax:</h5>
5359<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5360floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5361types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5362<pre>
5363 declare float @llvm.sin.f32(float %Val)
5364 declare double @llvm.sin.f64(double %Val)
5365 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5366 declare fp128 @llvm.sin.f128(fp128 %Val)
5367 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5368</pre>
5369
5370<h5>Overview:</h5>
5371
5372<p>
5373The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5374</p>
5375
5376<h5>Arguments:</h5>
5377
5378<p>
5379The argument and return value are floating point numbers of the same type.
5380</p>
5381
5382<h5>Semantics:</h5>
5383
5384<p>
5385This function returns the sine of the specified operand, returning the
5386same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5387conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5388</div>
5389
5390<!-- _______________________________________________________________________ -->
5391<div class="doc_subsubsection">
5392 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5393</div>
5394
5395<div class="doc_text">
5396
5397<h5>Syntax:</h5>
5398<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5399floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5400types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5401<pre>
5402 declare float @llvm.cos.f32(float %Val)
5403 declare double @llvm.cos.f64(double %Val)
5404 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5405 declare fp128 @llvm.cos.f128(fp128 %Val)
5406 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5407</pre>
5408
5409<h5>Overview:</h5>
5410
5411<p>
5412The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5413</p>
5414
5415<h5>Arguments:</h5>
5416
5417<p>
5418The argument and return value are floating point numbers of the same type.
5419</p>
5420
5421<h5>Semantics:</h5>
5422
5423<p>
5424This function returns the cosine of the specified operand, returning the
5425same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5426conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5427</div>
5428
5429<!-- _______________________________________________________________________ -->
5430<div class="doc_subsubsection">
5431 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5432</div>
5433
5434<div class="doc_text">
5435
5436<h5>Syntax:</h5>
5437<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5438floating point or vector of floating point type. Not all targets support all
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5439types however.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5440<pre>
5441 declare float @llvm.pow.f32(float %Val, float %Power)
5442 declare double @llvm.pow.f64(double %Val, double %Power)
5443 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5444 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5445 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5446</pre>
5447
5448<h5>Overview:</h5>
5449
5450<p>
5451The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5452specified (positive or negative) power.
5453</p>
5454
5455<h5>Arguments:</h5>
5456
5457<p>
5458The second argument is a floating point power, and the first is a value to
5459raise to that power.
5460</p>
5461
5462<h5>Semantics:</h5>
5463
5464<p>
5465This function returns the first value raised to the second power,
5466returning the
5467same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmaneaba92e2007-10-17 18:05:13 +0000[diff] [blame]5468conditions in the same way.</p>
Dan Gohman361079c2007-10-15 20:30:11 +0000[diff] [blame]5469</div>
5470
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5471
5472<!-- ======================================================================= -->
5473<div class="doc_subsection">
5474 <a name="int_manip">Bit Manipulation Intrinsics</a>
5475</div>
5476
5477<div class="doc_text">
5478<p>
5479LLVM provides intrinsics for a few important bit manipulation operations.
5480These allow efficient code generation for some algorithms.
5481</p>
5482
5483</div>
5484
5485<!-- _______________________________________________________________________ -->
5486<div class="doc_subsubsection">
5487 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
5488</div>
5489
5490<div class="doc_text">
5491
5492<h5>Syntax:</h5>
5493<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5494type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5495<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5496 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5497 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5498 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5499</pre>
5500
5501<h5>Overview:</h5>
5502
5503<p>
5504The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
5505values with an even number of bytes (positive multiple of 16 bits). These are
5506useful for performing operations on data that is not in the target's native
5507byte order.
5508</p>
5509
5510<h5>Semantics:</h5>
5511
5512<p>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5513The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5514and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5515intrinsic returns an i32 value that has the four bytes of the input i32
5516swapped, 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]5517i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5518<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5519additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
5520</p>
5521
5522</div>
5523
5524<!-- _______________________________________________________________________ -->
5525<div class="doc_subsubsection">
5526 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
5527</div>
5528
5529<div class="doc_text">
5530
5531<h5>Syntax:</h5>
5532<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]5533width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5534<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5535 declare i8 @llvm.ctpop.i8 (i8 &lt;src&gt;)
5536 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5537 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5538 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5539 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5540</pre>
5541
5542<h5>Overview:</h5>
5543
5544<p>
5545The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5546value.
5547</p>
5548
5549<h5>Arguments:</h5>
5550
5551<p>
5552The only argument is the value to be counted. The argument may be of any
5553integer type. The return type must match the argument type.
5554</p>
5555
5556<h5>Semantics:</h5>
5557
5558<p>
5559The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5560</p>
5561</div>
5562
5563<!-- _______________________________________________________________________ -->
5564<div class="doc_subsubsection">
5565 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
5566</div>
5567
5568<div class="doc_text">
5569
5570<h5>Syntax:</h5>
5571<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]5572integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5573<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5574 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5575 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5576 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5577 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5578 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5579</pre>
5580
5581<h5>Overview:</h5>
5582
5583<p>
5584The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5585leading zeros in a variable.
5586</p>
5587
5588<h5>Arguments:</h5>
5589
5590<p>
5591The only argument is the value to be counted. The argument may be of any
5592integer type. The return type must match the argument type.
5593</p>
5594
5595<h5>Semantics:</h5>
5596
5597<p>
5598The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5599in a variable. If the src == 0 then the result is the size in bits of the type
5600of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
5601</p>
5602</div>
5603
5604
5605
5606<!-- _______________________________________________________________________ -->
5607<div class="doc_subsubsection">
5608 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
5609</div>
5610
5611<div class="doc_text">
5612
5613<h5>Syntax:</h5>
5614<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]5615integer bit width. Not all targets support all bit widths however.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5616<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5617 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5618 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5619 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5620 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5621 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5622</pre>
5623
5624<h5>Overview:</h5>
5625
5626<p>
5627The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5628trailing zeros.
5629</p>
5630
5631<h5>Arguments:</h5>
5632
5633<p>
5634The only argument is the value to be counted. The argument may be of any
5635integer type. The return type must match the argument type.
5636</p>
5637
5638<h5>Semantics:</h5>
5639
5640<p>
5641The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5642in a variable. If the src == 0 then the result is the size in bits of the type
5643of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5644</p>
5645</div>
5646
5647<!-- _______________________________________________________________________ -->
5648<div class="doc_subsubsection">
5649 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
5650</div>
5651
5652<div class="doc_text">
5653
5654<h5>Syntax:</h5>
5655<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5656on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5657<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5658 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5659 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5660</pre>
5661
5662<h5>Overview:</h5>
5663<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
5664range of bits from an integer value and returns them in the same bit width as
5665the original value.</p>
5666
5667<h5>Arguments:</h5>
5668<p>The first argument, <tt>%val</tt> and the result may be integer types of
5669any bit width but they must have the same bit width. The second and third
5670arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
5671
5672<h5>Semantics:</h5>
5673<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
5674of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5675<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5676operates in forward mode.</p>
5677<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5678right by <tt>%loBit</tt> bits and then ANDing it with a mask with
5679only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5680<ol>
5681 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5682 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5683 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5684 to determine the number of bits to retain.</li>
5685 <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]5686 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5687</ol>
5688<p>In reverse mode, a similar computation is made except that the bits are
5689returned in the reverse order. So, for example, if <tt>X</tt> has the value
5690<tt>i16 0x0ACF (101011001111)</tt> and we apply
5691<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5692<tt>i16 0x0026 (000000100110)</tt>.</p>
5693</div>
5694
5695<div class="doc_subsubsection">
5696 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5697</div>
5698
5699<div class="doc_text">
5700
5701<h5>Syntax:</h5>
5702<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5703on any integer bit width.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5704<pre>
Chandler Carrutha228e392007-08-04 01:51:18 +0000[diff] [blame]5705 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5706 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]5707</pre>
5708
5709<h5>Overview:</h5>
5710<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5711of bits in an integer value with another integer value. It returns the integer
5712with the replaced bits.</p>
5713
5714<h5>Arguments:</h5>
5715<p>The first argument, <tt>%val</tt> and the result may be integer types of
5716any bit width but they must have the same bit width. <tt>%val</tt> is the value
5717whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5718integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5719type since they specify only a bit index.</p>
5720
5721<h5>Semantics:</h5>
5722<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5723of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5724<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5725operates in forward mode.</p>
5726<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5727truncating it down to the size of the replacement area or zero extending it
5728up to that size.</p>
5729<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5730are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5731in <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]5732to the <tt>%hi</tt>th bit.</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]5733<p>In reverse mode, a similar computation is made except that the bits are
5734reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5735<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]5736<h5>Examples:</h5>
5737<pre>
5738 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
5739 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
5740 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
5741 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
5742 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
5743</pre>
5744</div>
5745
5746<!-- ======================================================================= -->
5747<div class="doc_subsection">
5748 <a name="int_debugger">Debugger Intrinsics</a>
5749</div>
5750
5751<div class="doc_text">
5752<p>
5753The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
5754are described in the <a
5755href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
5756Debugging</a> document.
5757</p>
5758</div>
5759
5760
5761<!-- ======================================================================= -->
5762<div class="doc_subsection">
5763 <a name="int_eh">Exception Handling Intrinsics</a>
5764</div>
5765
5766<div class="doc_text">
5767<p> The LLVM exception handling intrinsics (which all start with
5768<tt>llvm.eh.</tt> prefix), are described in the <a
5769href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
5770Handling</a> document. </p>
5771</div>
5772
5773<!-- ======================================================================= -->
5774<div class="doc_subsection">
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5775 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5776</div>
5777
5778<div class="doc_text">
5779<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5780 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5781 the <tt>nest</tt> attribute, from a function. The result is a callable
5782 function pointer lacking the nest parameter - the caller does not need
5783 to provide a value for it. Instead, the value to use is stored in
5784 advance in a "trampoline", a block of memory usually allocated
5785 on the stack, which also contains code to splice the nest value into the
5786 argument list. This is used to implement the GCC nested function address
5787 extension.
5788</p>
5789<p>
5790 For example, if the function is
5791 <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]5792 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]5793<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5794 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5795 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
5796 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5797 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5798</pre>
Bill Wendlinge262b4c2007-09-22 09:23:55 +0000[diff] [blame]5799 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
5800 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5801</div>
5802
5803<!-- _______________________________________________________________________ -->
5804<div class="doc_subsubsection">
5805 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5806</div>
5807<div class="doc_text">
5808<h5>Syntax:</h5>
5809<pre>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5810declare 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]5811</pre>
5812<h5>Overview:</h5>
5813<p>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5814 This fills the memory pointed to by <tt>tramp</tt> with code
5815 and returns a function pointer suitable for executing it.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5816</p>
5817<h5>Arguments:</h5>
5818<p>
5819 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5820 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5821 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sands35012212007-08-22 23:39:54 +0000[diff] [blame]5822 intrinsic. Note that the size and the alignment are target-specific - LLVM
5823 currently provides no portable way of determining them, so a front-end that
5824 generates this intrinsic needs to have some target-specific knowledge.
5825 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]5826</p>
5827<h5>Semantics:</h5>
5828<p>
5829 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5830 dependent code, turning it into a function. A pointer to this function is
5831 returned, but needs to be bitcast to an
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5832 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands7407a9f2007-09-11 14:10:23 +0000[diff] [blame]5833 before being called. The new function's signature is the same as that of
5834 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
5835 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
5836 of pointer type. Calling the new function is equivalent to calling
5837 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
5838 missing <tt>nest</tt> argument. If, after calling
5839 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
5840 modified, then the effect of any later call to the returned function pointer is
5841 undefined.
Duncan Sands38947cd2007-07-27 12:58:54 +0000[diff] [blame]5842</p>
5843</div>
5844
5845<!-- ======================================================================= -->
5846<div class="doc_subsection">
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5847 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
5848</div>
5849
5850<div class="doc_text">
5851<p>
5852 These intrinsic functions expand the "universal IR" of LLVM to represent
5853 hardware constructs for atomic operations and memory synchronization. This
5854 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner96451482008-08-05 18:29:16 +0000[diff] [blame]5855 is aimed at a low enough level to allow any programming models or APIs
5856 (Application Programming Interfaces) which
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5857 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
5858 hardware behavior. Just as hardware provides a "universal IR" for source
5859 languages, it also provides a starting point for developing a "universal"
5860 atomic operation and synchronization IR.
5861</p>
5862<p>
5863 These do <em>not</em> form an API such as high-level threading libraries,
5864 software transaction memory systems, atomic primitives, and intrinsic
5865 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
5866 application libraries. The hardware interface provided by LLVM should allow
5867 a clean implementation of all of these APIs and parallel programming models.
5868 No one model or paradigm should be selected above others unless the hardware
5869 itself ubiquitously does so.
5870
5871</p>
5872</div>
5873
5874<!-- _______________________________________________________________________ -->
5875<div class="doc_subsubsection">
5876 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5877</div>
5878<div class="doc_text">
5879<h5>Syntax:</h5>
5880<pre>
5881declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
5882i1 &lt;device&gt; )
5883
5884</pre>
5885<h5>Overview:</h5>
5886<p>
5887 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5888 specific pairs of memory access types.
5889</p>
5890<h5>Arguments:</h5>
5891<p>
5892 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
5893 The first four arguments enables a specific barrier as listed below. The fith
5894 argument specifies that the barrier applies to io or device or uncached memory.
5895
5896</p>
5897 <ul>
5898 <li><tt>ll</tt>: load-load barrier</li>
5899 <li><tt>ls</tt>: load-store barrier</li>
5900 <li><tt>sl</tt>: store-load barrier</li>
5901 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]5902 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]5903 </ul>
5904<h5>Semantics:</h5>
5905<p>
5906 This intrinsic causes the system to enforce some ordering constraints upon
5907 the loads and stores of the program. This barrier does not indicate
5908 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5909 which they occur. For any of the specified pairs of load and store operations
5910 (f.ex. load-load, or store-load), all of the first operations preceding the
5911 barrier will complete before any of the second operations succeeding the
5912 barrier begin. Specifically the semantics for each pairing is as follows:
5913</p>
5914 <ul>
5915 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5916 after the barrier begins.</li>
5917
5918 <li><tt>ls</tt>: All loads before the barrier must complete before any
5919 store after the barrier begins.</li>
5920 <li><tt>ss</tt>: All stores before the barrier must complete before any
5921 store after the barrier begins.</li>
5922 <li><tt>sl</tt>: All stores before the barrier must complete before any
5923 load after the barrier begins.</li>
5924 </ul>
5925<p>
5926 These semantics are applied with a logical "and" behavior when more than one
5927 is enabled in a single memory barrier intrinsic.
5928</p>
5929<p>
5930 Backends may implement stronger barriers than those requested when they do not
5931 support as fine grained a barrier as requested. Some architectures do not
5932 need all types of barriers and on such architectures, these become noops.
5933</p>
5934<h5>Example:</h5>
5935<pre>
5936%ptr = malloc i32
5937 store i32 4, %ptr
5938
5939%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5940 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5941 <i>; guarantee the above finishes</i>
5942 store i32 8, %ptr <i>; before this begins</i>
5943</pre>
5944</div>
5945
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5946<!-- _______________________________________________________________________ -->
5947<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5948 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5949</div>
5950<div class="doc_text">
5951<h5>Syntax:</h5>
5952<p>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5953 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
5954 any integer bit width and for different address spaces. Not all targets
5955 support all bit widths however.</p>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5956
5957<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5958declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
5959declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
5960declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
5961declare 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]5962
5963</pre>
5964<h5>Overview:</h5>
5965<p>
5966 This loads a value in memory and compares it to a given value. If they are
5967 equal, it stores a new value into the memory.
5968</p>
5969<h5>Arguments:</h5>
5970<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]5971 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5972 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
5973 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
5974 this integer type. While any bit width integer may be used, targets may only
5975 lower representations they support in hardware.
5976
5977</p>
5978<h5>Semantics:</h5>
5979<p>
5980 This entire intrinsic must be executed atomically. It first loads the value
5981 in memory pointed to by <tt>ptr</tt> and compares it with the value
5982 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
5983 loaded value is yielded in all cases. This provides the equivalent of an
5984 atomic compare-and-swap operation within the SSA framework.
5985</p>
5986<h5>Examples:</h5>
5987
5988<pre>
5989%ptr = malloc i32
5990 store i32 4, %ptr
5991
5992%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5993%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]5994 <i>; yields {i32}:result1 = 4</i>
5995%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
5996%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
5997
5998%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]5999%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6000 <i>; yields {i32}:result2 = 8</i>
6001%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6002
6003%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6004</pre>
6005</div>
6006
6007<!-- _______________________________________________________________________ -->
6008<div class="doc_subsubsection">
6009 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6010</div>
6011<div class="doc_text">
6012<h5>Syntax:</h5>
6013
6014<p>
6015 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6016 integer bit width. Not all targets support all bit widths however.</p>
6017<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6018declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6019declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6020declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6021declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6022
6023</pre>
6024<h5>Overview:</h5>
6025<p>
6026 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6027 the value from memory. It then stores the value in <tt>val</tt> in the memory
6028 at <tt>ptr</tt>.
6029</p>
6030<h5>Arguments:</h5>
6031
6032<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6033 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6034 <tt>val</tt> argument and the result must be integers of the same bit width.
6035 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6036 integer type. The targets may only lower integer representations they
6037 support.
6038</p>
6039<h5>Semantics:</h5>
6040<p>
6041 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6042 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6043 equivalent of an atomic swap operation within the SSA framework.
6044
6045</p>
6046<h5>Examples:</h5>
6047<pre>
6048%ptr = malloc i32
6049 store i32 4, %ptr
6050
6051%val1 = add i32 4, 4
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6052%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6053 <i>; yields {i32}:result1 = 4</i>
6054%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6055%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6056
6057%val2 = add i32 1, 1
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6058%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6059 <i>; yields {i32}:result2 = 8</i>
6060
6061%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6062%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6063</pre>
6064</div>
6065
6066<!-- _______________________________________________________________________ -->
6067<div class="doc_subsubsection">
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6068 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6069
6070</div>
6071<div class="doc_text">
6072<h5>Syntax:</h5>
6073<p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6074 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]6075 integer bit width. Not all targets support all bit widths however.</p>
6076<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6077declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6078declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6079declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6080declare 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]6081
6082</pre>
6083<h5>Overview:</h5>
6084<p>
6085 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6086 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6087</p>
6088<h5>Arguments:</h5>
6089<p>
6090
6091 The intrinsic takes two arguments, the first a pointer to an integer value
6092 and the second an integer value. The result is also an integer value. These
6093 integer types can have any bit width, but they must all have the same bit
6094 width. The targets may only lower integer representations they support.
6095</p>
6096<h5>Semantics:</h5>
6097<p>
6098 This intrinsic does a series of operations atomically. It first loads the
6099 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6100 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6101</p>
6102
6103<h5>Examples:</h5>
6104<pre>
6105%ptr = malloc i32
6106 store i32 4, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6107%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6108 <i>; yields {i32}:result1 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6109%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6110 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6111%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6112 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6113%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharthe44f3902008-02-21 06:45:13 +0000[diff] [blame]6114</pre>
6115</div>
6116
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6117<!-- _______________________________________________________________________ -->
6118<div class="doc_subsubsection">
6119 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6120
6121</div>
6122<div class="doc_text">
6123<h5>Syntax:</h5>
6124<p>
6125 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]6126 any integer bit width and for different address spaces. Not all targets
6127 support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6128<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6129declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6130declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6131declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6132declare 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]6133
6134</pre>
6135<h5>Overview:</h5>
6136<p>
6137 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6138 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6139</p>
6140<h5>Arguments:</h5>
6141<p>
6142
6143 The intrinsic takes two arguments, the first a pointer to an integer value
6144 and the second an integer value. The result is also an integer value. These
6145 integer types can have any bit width, but they must all have the same bit
6146 width. The targets may only lower integer representations they support.
6147</p>
6148<h5>Semantics:</h5>
6149<p>
6150 This intrinsic does a series of operations atomically. It first loads the
6151 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6152 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6153</p>
6154
6155<h5>Examples:</h5>
6156<pre>
6157%ptr = malloc i32
6158 store i32 8, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6159%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6160 <i>; yields {i32}:result1 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6161%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6162 <i>; yields {i32}:result2 = 4</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6163%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6164 <i>; yields {i32}:result3 = 2</i>
6165%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6166</pre>
6167</div>
6168
6169<!-- _______________________________________________________________________ -->
6170<div class="doc_subsubsection">
6171 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6172 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6173 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6174 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6175
6176</div>
6177<div class="doc_text">
6178<h5>Syntax:</h5>
6179<p>
6180 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6181 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6182 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6183 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6184<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6185declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6186declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6187declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6188declare 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]6189
6190</pre>
6191
6192<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6193declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6194declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6195declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6196declare 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]6197
6198</pre>
6199
6200<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6201declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6202declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6203declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6204declare 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]6205
6206</pre>
6207
6208<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6209declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6210declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6211declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6212declare 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]6213
6214</pre>
6215<h5>Overview:</h5>
6216<p>
6217 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6218 the value stored in memory at <tt>ptr</tt>. It yields the original value
6219 at <tt>ptr</tt>.
6220</p>
6221<h5>Arguments:</h5>
6222<p>
6223
6224 These intrinsics take two arguments, the first a pointer to an integer value
6225 and the second an integer value. The result is also an integer value. These
6226 integer types can have any bit width, but they must all have the same bit
6227 width. The targets may only lower integer representations they support.
6228</p>
6229<h5>Semantics:</h5>
6230<p>
6231 These intrinsics does a series of operations atomically. They first load the
6232 value stored at <tt>ptr</tt>. They then do the bitwise operation
6233 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6234 value stored at <tt>ptr</tt>.
6235</p>
6236
6237<h5>Examples:</h5>
6238<pre>
6239%ptr = malloc i32
6240 store i32 0x0F0F, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6241%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6242 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6243%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6244 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6245%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6246 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6247%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6248 <i>; yields {i32}:result3 = FF</i>
6249%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6250</pre>
6251</div>
6252
6253
6254<!-- _______________________________________________________________________ -->
6255<div class="doc_subsubsection">
6256 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6257 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6258 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6259 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6260
6261</div>
6262<div class="doc_text">
6263<h5>Syntax:</h5>
6264<p>
6265 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6266 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6267 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6268 address spaces. Not all targets
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6269 support all bit widths however.</p>
6270<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6271declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6272declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6273declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6274declare 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]6275
6276</pre>
6277
6278<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6279declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6280declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6281declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6282declare 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]6283
6284</pre>
6285
6286<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6287declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6288declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6289declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6290declare 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]6291
6292</pre>
6293
6294<pre>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6295declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6296declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6297declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6298declare 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]6299
6300</pre>
6301<h5>Overview:</h5>
6302<p>
6303 These intrinsics takes the signed or unsigned minimum or maximum of
6304 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6305 original value at <tt>ptr</tt>.
6306</p>
6307<h5>Arguments:</h5>
6308<p>
6309
6310 These intrinsics take two arguments, the first a pointer to an integer value
6311 and the second an integer value. The result is also an integer value. These
6312 integer types can have any bit width, but they must all have the same bit
6313 width. The targets may only lower integer representations they support.
6314</p>
6315<h5>Semantics:</h5>
6316<p>
6317 These intrinsics does a series of operations atomically. They first load the
6318 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6319 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6320 the original value stored at <tt>ptr</tt>.
6321</p>
6322
6323<h5>Examples:</h5>
6324<pre>
6325%ptr = malloc i32
6326 store i32 7, %ptr
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6327%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6328 <i>; yields {i32}:result0 = 7</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6329%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6330 <i>; yields {i32}:result1 = -2</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6331%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6332 <i>; yields {i32}:result2 = 8</i>
Mon P Wangce3ac892008-07-30 04:36:53 +0000[diff] [blame]6333%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6bde9ec2008-06-25 08:15:39 +0000[diff] [blame]6334 <i>; yields {i32}:result3 = 8</i>
6335%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6336</pre>
6337</div>
Andrew Lenharth785610d2008-02-16 01:24:58 +0000[diff] [blame]6338
6339<!-- ======================================================================= -->
6340<div class="doc_subsection">
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6341 <a name="int_general">General Intrinsics</a>
6342</div>
6343
6344<div class="doc_text">
6345<p> This class of intrinsics is designed to be generic and has
6346no specific purpose. </p>
6347</div>
6348
6349<!-- _______________________________________________________________________ -->
6350<div class="doc_subsubsection">
6351 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6352</div>
6353
6354<div class="doc_text">
6355
6356<h5>Syntax:</h5>
6357<pre>
6358 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6359</pre>
6360
6361<h5>Overview:</h5>
6362
6363<p>
6364The '<tt>llvm.var.annotation</tt>' intrinsic
6365</p>
6366
6367<h5>Arguments:</h5>
6368
6369<p>
6370The first argument is a pointer to a value, the second is a pointer to a
6371global string, the third is a pointer to a global string which is the source
6372file name, and the last argument is the line number.
6373</p>
6374
6375<h5>Semantics:</h5>
6376
6377<p>
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6378This intrinsic allows annotation of local variables with arbitrary strings.
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6379This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6380annotations. These have no other defined use, they are ignored by code
6381generation and optimization.
6382</p>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6383</div>
6384
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6385<!-- _______________________________________________________________________ -->
6386<div class="doc_subsubsection">
Tanya Lattnerc9869b12007-09-21 23:57:59 +0000[diff] [blame]6387 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6388</div>
6389
6390<div class="doc_text">
6391
6392<h5>Syntax:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6393<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6394any integer bit width.
6395</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6396<pre>
Tanya Lattner09161fe2007-09-22 00:03:01 +0000[diff] [blame]6397 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6398 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6399 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6400 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6401 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]6402</pre>
6403
6404<h5>Overview:</h5>
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6405
6406<p>
6407The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6408</p>
6409
6410<h5>Arguments:</h5>
6411
6412<p>
6413The first argument is an integer value (result of some expression),
6414the second is a pointer to a global string, the third is a pointer to a global
6415string which is the source file name, and the last argument is the line number.
Tanya Lattnere545be72007-09-21 23:56:27 +0000[diff] [blame]6416It returns the value of the first argument.
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6417</p>
6418
6419<h5>Semantics:</h5>
6420
6421<p>
6422This intrinsic allows annotations to be put on arbitrary expressions
6423with arbitrary strings. This can be useful for special purpose optimizations
6424that want to look for these annotations. These have no other defined use, they
6425are ignored by code generation and optimization.
Dan Gohman2672f3e2008-10-14 16:51:45 +0000[diff] [blame]6426</p>
Tanya Lattnerb306a9e2007-09-21 22:59:12 +0000[diff] [blame]6427</div>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6428
Anton Korobeynikove6e764f2008-01-15 22:31:34 +0000[diff] [blame]6429<!-- _______________________________________________________________________ -->
6430<div class="doc_subsubsection">
6431 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
6432</div>
6433
6434<div class="doc_text">
6435
6436<h5>Syntax:</h5>
6437<pre>
6438 declare void @llvm.trap()
6439</pre>
6440
6441<h5>Overview:</h5>
6442
6443<p>
6444The '<tt>llvm.trap</tt>' intrinsic
6445</p>
6446
6447<h5>Arguments:</h5>
6448
6449<p>
6450None
6451</p>
6452
6453<h5>Semantics:</h5>
6454
6455<p>
6456This intrinsics is lowered to the target dependent trap instruction. If the
6457target does not have a trap instruction, this intrinsic will be lowered to the
6458call of the abort() function.
6459</p>
6460</div>
6461
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6462<!-- _______________________________________________________________________ -->
6463<div class="doc_subsubsection">
Misha Brukman5dd7f4d2008-11-22 23:55:29 +0000[diff] [blame]6464 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendlinge4164592008-11-19 05:56:17 +0000[diff] [blame]6465</div>
6466<div class="doc_text">
6467<h5>Syntax:</h5>
6468<pre>
6469declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
6470
6471</pre>
6472<h5>Overview:</h5>
6473<p>
6474 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
6475 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
6476 it is placed on the stack before local variables.
6477</p>
6478<h5>Arguments:</h5>
6479<p>
6480 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
6481 first argument is the value loaded from the stack guard
6482 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
6483 has enough space to hold the value of the guard.
6484</p>
6485<h5>Semantics:</h5>
6486<p>
6487 This intrinsic causes the prologue/epilogue inserter to force the position of
6488 the <tt>AllocaInst</tt> stack slot to be before local variables on the
6489 stack. This is to ensure that if a local variable on the stack is overwritten,
6490 it will destroy the value of the guard. When the function exits, the guard on
6491 the stack is checked against the original guard. If they're different, then
6492 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
6493</p>
6494</div>
6495
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6496<!-- *********************************************************************** -->
6497<hr>
6498<address>
6499 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame^]6500 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6501 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman947321d2008-12-11 17:34:48 +0000[diff] [blame^]6502 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6503
6504 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
6505 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
6506 Last modified: $Date$
6507</address>
Chris Lattner08497ce2008-01-04 04:33:49 +0000[diff] [blame]6508
Dan Gohmanf17a25c2007-07-18 16:29:46 +0000[diff] [blame]6509</body>
6510</html>