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5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencer3921c742004-08-26 20:44:00 +0000[diff] [blame]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.">
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11</head>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
26 <li><a href="#functionstructure">Function Structure</a></li>
27 </ol>
28 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]29 <li><a href="#typesystem">Type System</a>
30 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]31 <li><a href="#t_primitive">Primitive Types</a>
32 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]33 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]34 </ol>
35 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]36 <li><a href="#t_derived">Derived Types</a>
37 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]38 <li><a href="#t_array">Array Type</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]39 <li><a href="#t_function">Function Type</a></li>
40 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]41 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]42 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]43 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]44 </ol>
45 </li>
46 </ol>
47 </li>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]48 <li><a href="#constants">Constants</a>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]49 <ol>
50 <li><a href="#simpleconstants">Simple Constants</a>
51 <li><a href="#aggregateconstants">Aggregate Constants</a>
52 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
53 <li><a href="#undefvalues">Undefined Values</a>
54 <li><a href="#constantexprs">Constant Expressions</a>
55 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]56 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]57 <li><a href="#instref">Instruction Reference</a>
58 <ol>
59 <li><a href="#terminators">Terminator Instructions</a>
60 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]61 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
62 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]63 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
64 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]65 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]66 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]67 </ol>
68 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]69 <li><a href="#binaryops">Binary Operations</a>
70 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
72 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
73 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
74 <li><a href="#i_div">'<tt>div</tt>' Instruction</a></li>
75 <li><a href="#i_rem">'<tt>rem</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]76 <li><a href="#i_setcc">'<tt>set<i>cc</i></tt>' Instructions</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
80 <ol>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]81 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]82 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
84 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
85 <li><a href="#i_shr">'<tt>shr</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]86 </ol>
87 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]88 <li><a href="#memoryops">Memory Access Operations</a>
89 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]90 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
91 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
92 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
93 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
94 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
95 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
96 </ol>
97 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]98 <li><a href="#otherops">Other Operations</a>
99 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]100 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]101 <li><a href="#i_cast">'<tt>cast .. to</tt>' Instruction</a></li>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]102 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]103 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]104 <li><a href="#i_vanext">'<tt>vanext</tt>' Instruction</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]105 <li><a href="#i_vaarg">'<tt>vaarg</tt>' Instruction</a></li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]106 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]107 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]108 </ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]109 </li>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]110 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]111 <ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]112 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
113 <ol>
114 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
115 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
116 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
117 </ol>
118 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]119 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
120 <ol>
121 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
122 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
123 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
124 </ol>
125 </li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]126 <li><a href="#int_codegen">Code Generator Intrinsics</a>
127 <ol>
128 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
129 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]130 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]131 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]132 </ol>
133 </li>
134 <li><a href="#int_os">Operating System Intrinsics</a>
135 <ol>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]136 <li><a href="#i_readport">'<tt>llvm.readport</tt>' Intrinsic</a></li>
137 <li><a href="#i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a></li>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]138 <li><a href="#i_readio">'<tt>llvm.readio</tt>' Intrinsic</a></li>
139 <li><a href="#i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]140 </ol>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]141 <li><a href="#int_libc">Standard C Library Intrinsics</a>
142 <ol>
143 <li><a href="#i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a></li>
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]144 <li><a href="#i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a></li>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]145 <li><a href="#i_memset">'<tt>llvm.memset</tt>' Intrinsic</a></li>
Alkis Evlogimenos96853722004-06-12 19:19:14 +0000[diff] [blame]146 <li><a href="#i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a></li>
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]147 </ol>
148 </li>
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]149 <li><a href="#int_count">Bit counting Intrinsics</a>
150 <ol>
151 <li><a href="#int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic </a></li>
152 <li><a href="#int_cttz">'<tt>llvm.cttz</tt>' Intrinsic </a></li>
153 <li><a href="#int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic </a></li>
154 </ol>
155 </li>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]156 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]157 </ol>
158 </li>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]159</ol>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]160
161<div class="doc_author">
162 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
163 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]164</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]165
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]166<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]167<div class="doc_section"> <a name="abstract">Abstract </a></div>
168<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]169
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]170<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]171<p>This document is a reference manual for the LLVM assembly language.
172LLVM is an SSA based representation that provides type safety,
173low-level operations, flexibility, and the capability of representing
174'all' high-level languages cleanly. It is the common code
175representation used throughout all phases of the LLVM compilation
176strategy.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]177</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]178
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]179<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]180<div class="doc_section"> <a name="introduction">Introduction</a> </div>
181<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]182
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]183<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]184
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]185<p>The LLVM code representation is designed to be used in three
186different forms: as an in-memory compiler IR, as an on-disk bytecode
187representation (suitable for fast loading by a Just-In-Time compiler),
188and as a human readable assembly language representation. This allows
189LLVM to provide a powerful intermediate representation for efficient
190compiler transformations and analysis, while providing a natural means
191to debug and visualize the transformations. The three different forms
192of LLVM are all equivalent. This document describes the human readable
193representation and notation.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]194
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]195<p>The LLVM representation aims to be a light-weight and low-level
196while being expressive, typed, and extensible at the same time. It
197aims to be a "universal IR" of sorts, by being at a low enough level
198that high-level ideas may be cleanly mapped to it (similar to how
199microprocessors are "universal IR's", allowing many source languages to
200be mapped to them). By providing type information, LLVM can be used as
201the target of optimizations: for example, through pointer analysis, it
202can be proven that a C automatic variable is never accessed outside of
203the current function... allowing it to be promoted to a simple SSA
204value instead of a memory location.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]205
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]206</div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]207
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]208<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]209<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]210
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]211<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]212
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]213<p>It is important to note that this document describes 'well formed'
214LLVM assembly language. There is a difference between what the parser
215accepts and what is considered 'well formed'. For example, the
216following instruction is syntactically okay, but not well formed:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]217
218<pre>
219 %x = <a href="#i_add">add</a> int 1, %x
220</pre>
221
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]222<p>...because the definition of <tt>%x</tt> does not dominate all of
223its uses. The LLVM infrastructure provides a verification pass that may
224be used to verify that an LLVM module is well formed. This pass is
225automatically run by the parser after parsing input assembly, and by
226the optimizer before it outputs bytecode. The violations pointed out
227by the verifier pass indicate bugs in transformation passes or input to
228the parser.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]229
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]230<!-- Describe the typesetting conventions here. --> </div>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]231
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]232<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]233<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]234<!-- *********************************************************************** -->
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]235
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]236<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]237
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]238<p>LLVM uses three different forms of identifiers, for different
239purposes:</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]240
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]241<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]242 <li>Named values are represented as a string of characters with a '%' prefix.
243 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
244 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
245 Identifiers which require other characters in their names can be surrounded
246 with quotes. In this way, anything except a <tt>"</tt> character can be used
247 in a name.</li>
248
249 <li>Unnamed values are represented as an unsigned numeric value with a '%'
250 prefix. For example, %12, %2, %44.</li>
251
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]252 <li>Constants, which are described in a <a href="#constants">section about
253 constants</a>, below.</li>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]254</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]255
256<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
257don't need to worry about name clashes with reserved words, and the set of
258reserved words may be expanded in the future without penalty. Additionally,
259unnamed identifiers allow a compiler to quickly come up with a temporary
260variable without having to avoid symbol table conflicts.</p>
261
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]262<p>Reserved words in LLVM are very similar to reserved words in other
263languages. There are keywords for different opcodes ('<tt><a
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]264href="#i_add">add</a></tt>', '<tt><a href="#i_cast">cast</a></tt>', '<tt><a
265href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
266href="#t_void">void</a></tt>', '<tt><a href="#t_uint">uint</a></tt>', etc...),
267and others. These reserved words cannot conflict with variable names, because
268none of them start with a '%' character.</p>
269
270<p>Here is an example of LLVM code to multiply the integer variable
271'<tt>%X</tt>' by 8:</p>
272
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]273<p>The easy way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]274
275<pre>
276 %result = <a href="#i_mul">mul</a> uint %X, 8
277</pre>
278
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]279<p>After strength reduction:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]280
281<pre>
282 %result = <a href="#i_shl">shl</a> uint %X, ubyte 3
283</pre>
284
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]285<p>And the hard way:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]286
287<pre>
288 <a href="#i_add">add</a> uint %X, %X <i>; yields {uint}:%0</i>
289 <a href="#i_add">add</a> uint %0, %0 <i>; yields {uint}:%1</i>
290 %result = <a href="#i_add">add</a> uint %1, %1
291</pre>
292
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]293<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
294important lexical features of LLVM:</p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]295
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]296<ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]297
298 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
299 line.</li>
300
301 <li>Unnamed temporaries are created when the result of a computation is not
302 assigned to a named value.</li>
303
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]304 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]305
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]306</ol>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]307
308<p>...and it also show a convention that we follow in this document. When
309demonstrating instructions, we will follow an instruction with a comment that
310defines the type and name of value produced. Comments are shown in italic
311text.</p>
312
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]313</div>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]314
315<!-- *********************************************************************** -->
316<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
317<!-- *********************************************************************** -->
318
319<!-- ======================================================================= -->
320<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
321</div>
322
323<div class="doc_text">
324
325<p>LLVM programs are composed of "Module"s, each of which is a
326translation unit of the input programs. Each module consists of
327functions, global variables, and symbol table entries. Modules may be
328combined together with the LLVM linker, which merges function (and
329global variable) definitions, resolves forward declarations, and merges
330symbol table entries. Here is an example of the "hello world" module:</p>
331
332<pre><i>; Declare the string constant as a global constant...</i>
333<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
334 href="#globalvars">constant</a> <a href="#t_array">[13 x sbyte]</a> c"hello world\0A\00" <i>; [13 x sbyte]*</i>
335
336<i>; External declaration of the puts function</i>
337<a href="#functionstructure">declare</a> int %puts(sbyte*) <i>; int(sbyte*)* </i>
338
339<i>; Definition of main function</i>
340int %main() { <i>; int()* </i>
341 <i>; Convert [13x sbyte]* to sbyte *...</i>
342 %cast210 = <a
343 href="#i_getelementptr">getelementptr</a> [13 x sbyte]* %.LC0, long 0, long 0 <i>; sbyte*</i>
344
345 <i>; Call puts function to write out the string to stdout...</i>
346 <a
347 href="#i_call">call</a> int %puts(sbyte* %cast210) <i>; int</i>
348 <a
349 href="#i_ret">ret</a> int 0<br>}<br></pre>
350
351<p>This example is made up of a <a href="#globalvars">global variable</a>
352named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
353function, and a <a href="#functionstructure">function definition</a>
354for "<tt>main</tt>".</p>
355
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]356<p>In general, a module is made up of a list of global values,
357where both functions and global variables are global values. Global values are
358represented by a pointer to a memory location (in this case, a pointer to an
359array of char, and a pointer to a function), and have one of the following <a
360href="#linkage">linkage types</a>.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]361
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]362</div>
363
364<!-- ======================================================================= -->
365<div class="doc_subsection">
366 <a name="linkage">Linkage Types</a>
367</div>
368
369<div class="doc_text">
370
371<p>
372All Global Variables and Functions have one of the following types of linkage:
373</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]374
375<dl>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]376
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]377 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]378
379 <dd>Global values with internal linkage are only directly accessible by
380 objects in the current module. In particular, linking code into a module with
381 an internal global value may cause the internal to be renamed as necessary to
382 avoid collisions. Because the symbol is internal to the module, all
383 references can be updated. This corresponds to the notion of the
384 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]385 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]386
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]387 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]388
389 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
390 the twist that linking together two modules defining the same
391 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
392 is typically used to implement inline functions. Unreferenced
393 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]394 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]395
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]396 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]397
398 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
399 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
400 used to implement constructs in C such as "<tt>int X;</tt>" at global scope.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]401 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]402
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]403 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]404
405 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
406 pointer to array type. When two global variables with appending linkage are
407 linked together, the two global arrays are appended together. This is the
408 LLVM, typesafe, equivalent of having the system linker append together
409 "sections" with identical names when .o files are linked.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]410 </dd>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]411
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]412 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]413
414 <dd>If none of the above identifiers are used, the global is externally
415 visible, meaning that it participates in linkage and can be used to resolve
416 external symbol references.
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]417 </dd>
418</dl>
419
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]420<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
421variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
422variable and was linked with this one, one of the two would be renamed,
423preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
424external (i.e., lacking any linkage declarations), they are accessible
425outside of the current module. It is illegal for a function <i>declaration</i>
426to have any linkage type other than "externally visible".</a></p>
Chris Lattnere5d947b2004-12-09 16:36:40 +0000[diff] [blame]427
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]428</div>
429
430<!-- ======================================================================= -->
431<div class="doc_subsection">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]432 <a name="callingconv">Calling Conventions</a>
433</div>
434
435<div class="doc_text">
436
437<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
438and <a href="#i_invoke">invokes</a> can all have an optional calling convention
439specified for the call. The calling convention of any pair of dynamic
440caller/callee must match, or the behavior of the program is undefined. The
441following calling conventions are supported by LLVM, and more may be added in
442the future:</p>
443
444<dl>
445 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
446
447 <dd>This calling convention (the default if no other calling convention is
448 specified) matches the target C calling conventions. This calling convention
449 supports varargs function calls, and tolerates some mismatch in the declared
450 prototype and implemented declaration of the function (as does normal C).
451 </dd>
452
453 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
454
455 <dd>This calling convention attempts to make calls as fast as possible
456 (e.g. by passing things in registers). This calling convention allows the
457 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner8cdc5bc2005-05-06 23:08:23 +0000[diff] [blame]458 without having to conform to an externally specified ABI. Implementations of
459 this convention should allow arbitrary tail call optimization to be supported.
460 This calling convention does not support varargs and requires the prototype of
461 all callees to exactly match the prototype of the function definition.
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]462 </dd>
463
464 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
465
466 <dd>This calling convention attempts to make code in the caller as efficient
467 as possible under the assumption that the call is not commonly executed. As
468 such, these calls often preserve all registers so that the call does not break
469 any live ranges in the caller side. This calling convention does not support
470 varargs and requires the prototype of all callees to exactly match the
471 prototype of the function definition.
472 </dd>
473
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]474 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]475
476 <dd>Any calling convention may be specified by number, allowing
477 target-specific calling conventions to be used. Target specific calling
478 conventions start at 64.
479 </dd>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]480</dl>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]481
482<p>More calling conventions can be added/defined on an as-needed basis, to
483support pascal conventions or any other well-known target-independent
484convention.</p>
485
486</div>
487
488<!-- ======================================================================= -->
489<div class="doc_subsection">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]490 <a name="globalvars">Global Variables</a>
491</div>
492
493<div class="doc_text">
494
Chris Lattner3689a342005-02-12 19:30:21 +0000[diff] [blame]495<p>Global variables define regions of memory allocated at compilation time
496instead of run-time. Global variables may optionally be initialized. A
497variable may be defined as a global "constant", which indicates that the
498contents of the variable will <b>never</b> be modified (enabling better
499optimization, allowing the global data to be placed in the read-only section of
500an executable, etc). Note that variables that need runtime initialization
501cannot be marked "constant", as there is a store to the variable.</p>
502
503<p>
504LLVM explicitly allows <em>declarations</em> of global variables to be marked
505constant, even if the final definition of the global is not. This capability
506can be used to enable slightly better optimization of the program, but requires
507the language definition to guarantee that optimizations based on the
508'constantness' are valid for the translation units that do not include the
509definition.
510</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]511
512<p>As SSA values, global variables define pointer values that are in
513scope (i.e. they dominate) all basic blocks in the program. Global
514variables always define a pointer to their "content" type because they
515describe a region of memory, and all memory objects in LLVM are
516accessed through pointers.</p>
517
518</div>
519
520
521<!-- ======================================================================= -->
522<div class="doc_subsection">
523 <a name="functionstructure">Functions</a>
524</div>
525
526<div class="doc_text">
527
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]528<p>LLVM function definitions consist of an optional <a href="#linkage">linkage
529type</a>, an optional <a href="#callingconv">calling convention</a>, a return
530type, a function name, a (possibly empty) argument list, an opening curly brace,
531a list of basic blocks, and a closing curly brace. LLVM function declarations
532are defined with the "<tt>declare</tt>" keyword, an optional <a
533href="#callingconv">calling convention</a>, a return type, a function name, and
534a possibly empty list of arguments.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]535
536<p>A function definition contains a list of basic blocks, forming the CFG for
537the function. Each basic block may optionally start with a label (giving the
538basic block a symbol table entry), contains a list of instructions, and ends
539with a <a href="#terminators">terminator</a> instruction (such as a branch or
540function return).</p>
541
542<p>The first basic block in program is special in two ways: it is immediately
543executed on entrance to the function, and it is not allowed to have predecessor
544basic blocks (i.e. there can not be any branches to the entry block of a
545function). Because the block can have no predecessors, it also cannot have any
546<a href="#i_phi">PHI nodes</a>.</p>
547
548<p>LLVM functions are identified by their name and type signature. Hence, two
549functions with the same name but different parameter lists or return values are
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]550considered different functions, and LLVM will resolve references to each
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]551appropriately.</p>
552
553</div>
554
555
556
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]557<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]558<div class="doc_section"> <a name="typesystem">Type System</a> </div>
559<!-- *********************************************************************** -->
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]560
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]561<div class="doc_text">
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]562
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]563<p>The LLVM type system is one of the most important features of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]564intermediate representation. Being typed enables a number of
565optimizations to be performed on the IR directly, without having to do
566extra analyses on the side before the transformation. A strong type
567system makes it easier to read the generated code and enables novel
568analyses and transformations that are not feasible to perform on normal
569three address code representations.</p>
Chris Lattnerfa730212004-12-09 16:11:40 +0000[diff] [blame]570
571</div>
572
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]573<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]574<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]575<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]576<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]577system. The current set of primitive types is as follows:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]578
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]579<table class="layout">
580 <tr class="layout">
581 <td class="left">
582 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]583 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]584 <tr><th>Type</th><th>Description</th></tr>
585 <tr><td><tt>void</tt></td><td>No value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]586 <tr><td><tt>ubyte</tt></td><td>Unsigned 8-bit value</td></tr>
587 <tr><td><tt>ushort</tt></td><td>Unsigned 16-bit value</td></tr>
588 <tr><td><tt>uint</tt></td><td>Unsigned 32-bit value</td></tr>
589 <tr><td><tt>ulong</tt></td><td>Unsigned 64-bit value</td></tr>
590 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]591 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]592 </tbody>
593 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]594 </td>
595 <td class="right">
596 <table>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]597 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]598 <tr><th>Type</th><th>Description</th></tr>
599 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]600 <tr><td><tt>sbyte</tt></td><td>Signed 8-bit value</td></tr>
601 <tr><td><tt>short</tt></td><td>Signed 16-bit value</td></tr>
602 <tr><td><tt>int</tt></td><td>Signed 32-bit value</td></tr>
603 <tr><td><tt>long</tt></td><td>Signed 64-bit value</td></tr>
604 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]605 </tbody>
606 </table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]607 </td>
608 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]609</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]610</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]611
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]612<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]613<div class="doc_subsubsection"> <a name="t_classifications">Type
614Classifications</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]615<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]616<p>These different primitive types fall into a few useful
617classifications:</p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]618
619<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]620 <tbody>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]621 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]622 <tr>
623 <td><a name="t_signed">signed</a></td>
624 <td><tt>sbyte, short, int, long, float, double</tt></td>
625 </tr>
626 <tr>
627 <td><a name="t_unsigned">unsigned</a></td>
628 <td><tt>ubyte, ushort, uint, ulong</tt></td>
629 </tr>
630 <tr>
631 <td><a name="t_integer">integer</a></td>
632 <td><tt>ubyte, sbyte, ushort, short, uint, int, ulong, long</tt></td>
633 </tr>
634 <tr>
635 <td><a name="t_integral">integral</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]636 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long</tt>
637 </td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]638 </tr>
639 <tr>
640 <td><a name="t_floating">floating point</a></td>
641 <td><tt>float, double</tt></td>
642 </tr>
643 <tr>
644 <td><a name="t_firstclass">first class</a></td>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]645 <td><tt>bool, ubyte, sbyte, ushort, short, uint, int, ulong, long,<br>
646 float, double, <a href="#t_pointer">pointer</a>,
647 <a href="#t_packed">packed</a></tt></td>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]648 </tr>
649 </tbody>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]650</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]651
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]652<p>The <a href="#t_firstclass">first class</a> types are perhaps the
653most important. Values of these types are the only ones which can be
654produced by instructions, passed as arguments, or used as operands to
655instructions. This means that all structures and arrays must be
656manipulated either by pointer or by component.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]657</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]658
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]659<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]660<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]661
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]662<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]663
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]664<p>The real power in LLVM comes from the derived types in the system.
665This is what allows a programmer to represent arrays, functions,
666pointers, and other useful types. Note that these derived types may be
667recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]668
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]669</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]670
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]671<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]672<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]673
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]674<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]675
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]676<h5>Overview:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]677
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]678<p>The array type is a very simple derived type that arranges elements
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]679sequentially in memory. The array type requires a size (number of
680elements) and an underlying data type.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]681
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]682<h5>Syntax:</h5>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]683
684<pre>
685 [&lt;# elements&gt; x &lt;elementtype&gt;]
686</pre>
687
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]688<p>The number of elements is a constant integer value, elementtype may
689be any type with a size.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]690
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]691<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]692<table class="layout">
693 <tr class="layout">
694 <td class="left">
695 <tt>[40 x int ]</tt><br/>
696 <tt>[41 x int ]</tt><br/>
697 <tt>[40 x uint]</tt><br/>
698 </td>
699 <td class="left">
700 Array of 40 integer values.<br/>
701 Array of 41 integer values.<br/>
702 Array of 40 unsigned integer values.<br/>
703 </td>
704 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]705</table>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]706<p>Here are some examples of multidimensional arrays:</p>
707<table class="layout">
708 <tr class="layout">
709 <td class="left">
710 <tt>[3 x [4 x int]]</tt><br/>
711 <tt>[12 x [10 x float]]</tt><br/>
712 <tt>[2 x [3 x [4 x uint]]]</tt><br/>
713 </td>
714 <td class="left">
715 3x4 array integer values.<br/>
716 12x10 array of single precision floating point values.<br/>
717 2x3x4 array of unsigned integer values.<br/>
718 </td>
719 </tr>
720</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]721</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]722
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]723<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]724<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]725<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]726<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]727<p>The function type can be thought of as a function signature. It
728consists of a return type and a list of formal parameter types.
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]729Function types are usually used to build virtual function tables
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]730(which are structures of pointers to functions), for indirect function
731calls, and when defining a function.</p>
John Criswell009900b2003-11-25 21:45:46 +0000[diff] [blame]732<p>
733The return type of a function type cannot be an aggregate type.
734</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]735<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]736<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]737<p>Where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
738specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]739which indicates that the function takes a variable number of arguments.
740Variable argument functions can access their arguments with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]741 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]742<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]743<table class="layout">
744 <tr class="layout">
745 <td class="left">
746 <tt>int (int)</tt> <br/>
747 <tt>float (int, int *) *</tt><br/>
748 <tt>int (sbyte *, ...)</tt><br/>
749 </td>
750 <td class="left">
751 function taking an <tt>int</tt>, returning an <tt>int</tt><br/>
752 <a href="#t_pointer">Pointer</a> to a function that takes an
Misha Brukmanc24b7582004-08-12 20:16:08 +0000[diff] [blame]753 <tt>int</tt> and a <a href="#t_pointer">pointer</a> to <tt>int</tt>,
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]754 returning <tt>float</tt>.<br/>
755 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
756 to <tt>sbyte</tt> (signed char in C), which returns an integer. This is
757 the signature for <tt>printf</tt> in LLVM.<br/>
758 </td>
759 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]760</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]761
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]762</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]763<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]764<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]765<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]766<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]767<p>The structure type is used to represent a collection of data members
768together in memory. The packing of the field types is defined to match
769the ABI of the underlying processor. The elements of a structure may
770be any type that has a size.</p>
771<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
772and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
773field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
774instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]775<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]776<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]777<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]778<table class="layout">
779 <tr class="layout">
780 <td class="left">
781 <tt>{ int, int, int }</tt><br/>
782 <tt>{ float, int (int) * }</tt><br/>
783 </td>
784 <td class="left">
785 a triple of three <tt>int</tt> values<br/>
786 A pair, where the first element is a <tt>float</tt> and the second element
787 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
788 that takes an <tt>int</tt>, returning an <tt>int</tt>.<br/>
789 </td>
790 </tr>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]791</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]792</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]793
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]794<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]795<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]796<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]797<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]798<p>As in many languages, the pointer type represents a pointer or
799reference to another object, which must live in memory.</p>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]800<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]801<pre> &lt;type&gt; *<br></pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]802<h5>Examples:</h5>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]803<table class="layout">
804 <tr class="layout">
805 <td class="left">
806 <tt>[4x int]*</tt><br/>
807 <tt>int (int *) *</tt><br/>
808 </td>
809 <td class="left">
810 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
811 four <tt>int</tt> values<br/>
812 A <a href="#t_pointer">pointer</a> to a <a
Chris Lattnera977c482005-02-19 02:22:14 +0000[diff] [blame]813 href="#t_function">function</a> that takes an <tt>int*</tt>, returning an
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]814 <tt>int</tt>.<br/>
815 </td>
816 </tr>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]817</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]818</div>
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]819
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]820<!-- _______________________________________________________________________ -->
821<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]822<div class="doc_text">
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]823
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]824<h5>Overview:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]825
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]826<p>A packed type is a simple derived type that represents a vector
827of elements. Packed types are used when multiple primitive data
828are operated in parallel using a single instruction (SIMD).
829A packed type requires a size (number of
830elements) and an underlying primitive data type. Packed types are
831considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]832
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]833<h5>Syntax:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]834
835<pre>
836 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
837</pre>
838
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]839<p>The number of elements is a constant integer value, elementtype may
840be any integral or floating point type.</p>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]841
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]842<h5>Examples:</h5>
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]843
Reid Spencerd3f876c2004-11-01 08:19:36 +0000[diff] [blame]844<table class="layout">
845 <tr class="layout">
846 <td class="left">
847 <tt>&lt;4 x int&gt;</tt><br/>
848 <tt>&lt;8 x float&gt;</tt><br/>
849 <tt>&lt;2 x uint&gt;</tt><br/>
850 </td>
851 <td class="left">
852 Packed vector of 4 integer values.<br/>
853 Packed vector of 8 floating-point values.<br/>
854 Packed vector of 2 unsigned integer values.<br/>
855 </td>
856 </tr>
857</table>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]858</div>
859
Chris Lattner69c11bb2005-04-25 17:34:15 +0000[diff] [blame]860<!-- _______________________________________________________________________ -->
861<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
862<div class="doc_text">
863
864<h5>Overview:</h5>
865
866<p>Opaque types are used to represent unknown types in the system. This
867corresponds (for example) to the C notion of a foward declared structure type.
868In LLVM, opaque types can eventually be resolved to any type (not just a
869structure type).</p>
870
871<h5>Syntax:</h5>
872
873<pre>
874 opaque
875</pre>
876
877<h5>Examples:</h5>
878
879<table class="layout">
880 <tr class="layout">
881 <td class="left">
882 <tt>opaque</tt>
883 </td>
884 <td class="left">
885 An opaque type.<br/>
886 </td>
887 </tr>
888</table>
889</div>
890
891
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]892<!-- *********************************************************************** -->
893<div class="doc_section"> <a name="constants">Constants</a> </div>
894<!-- *********************************************************************** -->
895
896<div class="doc_text">
897
898<p>LLVM has several different basic types of constants. This section describes
899them all and their syntax.</p>
900
901</div>
902
903<!-- ======================================================================= -->
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]904<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]905
906<div class="doc_text">
907
908<dl>
909 <dt><b>Boolean constants</b></dt>
910
911 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
912 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
913 </dd>
914
915 <dt><b>Integer constants</b></dt>
916
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]917 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]918 href="#t_integer">integer</a> type. Negative numbers may be used with signed
919 integer types.
920 </dd>
921
922 <dt><b>Floating point constants</b></dt>
923
924 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
925 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]926 notation. Floating point constants have an optional hexadecimal
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]927 notation (see below). Floating point constants must have a <a
928 href="#t_floating">floating point</a> type. </dd>
929
930 <dt><b>Null pointer constants</b></dt>
931
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]932 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]933 and must be of <a href="#t_pointer">pointer type</a>.</dd>
934
935</dl>
936
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]937<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]938of floating point constants. For example, the form '<tt>double
9390x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
9404.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencercc16dc32004-12-09 18:02:53 +0000[diff] [blame]941(and the only time that they are generated by the disassembler) is when a
942floating point constant must be emitted but it cannot be represented as a
943decimal floating point number. For example, NaN's, infinities, and other
944special values are represented in their IEEE hexadecimal format so that
945assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]946
947</div>
948
949<!-- ======================================================================= -->
950<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
951</div>
952
953<div class="doc_text">
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]954<p>Aggregate constants arise from aggregation of simple constants
955and smaller aggregate constants.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]956
957<dl>
958 <dt><b>Structure constants</b></dt>
959
960 <dd>Structure constants are represented with notation similar to structure
961 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]962 (<tt>{}</tt>)). For example: "<tt>{ int 4, float 17.0, int* %G }</tt>",
963 where "<tt>%G</tt>" is declared as "<tt>%G = external global int</tt>". Structure constants
964 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]965 types of elements must match those specified by the type.
966 </dd>
967
968 <dt><b>Array constants</b></dt>
969
970 <dd>Array constants are represented with notation similar to array type
971 definitions (a comma separated list of elements, surrounded by square brackets
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]972 (<tt>[]</tt>)). For example: "<tt>[ int 42, int 11, int 74 ]</tt>". Array
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]973 constants must have <a href="#t_array">array type</a>, and the number and
974 types of elements must match those specified by the type.
975 </dd>
976
977 <dt><b>Packed constants</b></dt>
978
979 <dd>Packed constants are represented with notation similar to packed type
980 definitions (a comma separated list of elements, surrounded by
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]981 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; int 42,
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]982 int 11, int 74, int 100 &gt;</tt>". Packed constants must have <a
983 href="#t_packed">packed type</a>, and the number and types of elements must
984 match those specified by the type.
985 </dd>
986
987 <dt><b>Zero initialization</b></dt>
988
989 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
990 value to zero of <em>any</em> type, including scalar and aggregate types.
991 This is often used to avoid having to print large zero initializers (e.g. for
992 large arrays), and is always exactly equivalent to using explicit zero
993 initializers.
994 </dd>
995</dl>
996
997</div>
998
999<!-- ======================================================================= -->
1000<div class="doc_subsection">
1001 <a name="globalconstants">Global Variable and Function Addresses</a>
1002</div>
1003
1004<div class="doc_text">
1005
1006<p>The addresses of <a href="#globalvars">global variables</a> and <a
1007href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1008constants. These constants are explicitly referenced when the <a
1009href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1010href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1011file:</p>
1012
1013<pre>
1014 %X = global int 17
1015 %Y = global int 42
1016 %Z = global [2 x int*] [ int* %X, int* %Y ]
1017</pre>
1018
1019</div>
1020
1021<!-- ======================================================================= -->
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1022<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1023<div class="doc_text">
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1024 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
1025 no specific value. Undefined values may be of any type, and be used anywhere
1026 a constant is permitted.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1027
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1028 <p>Undefined values indicate to the compiler that the program is well defined
1029 no matter what value is used, giving the compiler more freedom to optimize.
1030 </p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1031</div>
1032
1033<!-- ======================================================================= -->
1034<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1035</div>
1036
1037<div class="doc_text">
1038
1039<p>Constant expressions are used to allow expressions involving other constants
1040to be used as constants. Constant expressions may be of any <a
1041href="#t_firstclass">first class</a> type, and may involve any LLVM operation
1042that does not have side effects (e.g. load and call are not supported). The
1043following is the syntax for constant expressions:</p>
1044
1045<dl>
1046 <dt><b><tt>cast ( CST to TYPE )</tt></b></dt>
1047
1048 <dd>Cast a constant to another type.</dd>
1049
1050 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1051
1052 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1053 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1054 instruction, the index list may have zero or more indexes, which are required
1055 to make sense for the type of "CSTPTR".</dd>
1056
1057 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1058
Reid Spencer2dc45b82004-12-09 18:13:12 +0000[diff] [blame]1059 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1060 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1061 binary</a> operations. The constraints on operands are the same as those for
1062 the corresponding instruction (e.g. no bitwise operations on floating point
1063 are allowed).</dd>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1064</dl>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1065</div>
Chris Lattner9ee5d222004-03-08 16:49:10 +0000[diff] [blame]1066
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1067<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1068<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1069<!-- *********************************************************************** -->
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1070
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1071<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1072
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1073<p>The LLVM instruction set consists of several different
1074classifications of instructions: <a href="#terminators">terminator
1075instructions</a>, <a href="#binaryops">binary instructions</a>, <a
1076 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1077instructions</a>.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1078
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1079</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1080
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1081<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1082<div class="doc_subsection"> <a name="terminators">Terminator
1083Instructions</a> </div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1084
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1085<div class="doc_text">
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1086
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1087<p>As mentioned <a href="#functionstructure">previously</a>, every
1088basic block in a program ends with a "Terminator" instruction, which
1089indicates which block should be executed after the current block is
1090finished. These terminator instructions typically yield a '<tt>void</tt>'
1091value: they produce control flow, not values (the one exception being
1092the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1093<p>There are six different terminator instructions: the '<a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1094 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1095instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1096the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1097 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1098 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1099
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1100</div>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]1101
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1102<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1103<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1104Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1105<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1106<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1107<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1108 ret void <i>; Return from void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1109</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1110<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1111<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
1112value) from a function, back to the caller.</p>
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]1113<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1114returns a value and then causes control flow, and one that just causes
1115control flow to occur.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1116<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1117<p>The '<tt>ret</tt>' instruction may return any '<a
1118 href="#t_firstclass">first class</a>' type. Notice that a function is
1119not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1120instruction inside of the function that returns a value that does not
1121match the return type of the function.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1122<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1123<p>When the '<tt>ret</tt>' instruction is executed, control flow
1124returns back to the calling function's context. If the caller is a "<a
John Criswellfa081872004-06-25 15:16:57 +0000[diff] [blame]1125 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1126the instruction after the call. If the caller was an "<a
1127 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
1128at the beginning "normal" of the destination block. If the instruction
1129returns a value, that value shall set the call or invoke instruction's
1130return value.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1131<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1132<pre> ret int 5 <i>; Return an integer value of 5</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1133 ret void <i>; Return from a void function</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1134</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1135</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1136<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1137<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1138<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1139<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1140<pre> br bool &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1141</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1142<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1143<p>The '<tt>br</tt>' instruction is used to cause control flow to
1144transfer to a different basic block in the current function. There are
1145two forms of this instruction, corresponding to a conditional branch
1146and an unconditional branch.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1147<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1148<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1149single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1150unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1151value as a target.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1152<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1153<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1154argument is evaluated. If the value is <tt>true</tt>, control flows
1155to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1156control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1157<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1158<pre>Test:<br> %cond = <a href="#i_setcc">seteq</a> int %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1159 href="#i_ret">ret</a> int 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> int 0<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1160</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1161<!-- _______________________________________________________________________ -->
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1162<div class="doc_subsubsection">
1163 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1164</div>
1165
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1166<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1167<h5>Syntax:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1168
1169<pre>
1170 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1171</pre>
1172
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1173<h5>Overview:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1174
1175<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1176several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1177instruction, allowing a branch to occur to one of many possible
1178destinations.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1179
1180
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1181<h5>Arguments:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1182
1183<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1184comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1185an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1186table is not allowed to contain duplicate constant entries.</p>
1187
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1188<h5>Semantics:</h5>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1189
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1190<p>The <tt>switch</tt> instruction specifies a table of values and
1191destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1192table is searched for the given value. If the value is found, control flow is
1193transfered to the corresponding destination; otherwise, control flow is
1194transfered to the default destination.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1195
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1196<h5>Implementation:</h5>
1197
1198<p>Depending on properties of the target machine and the particular
1199<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswell84114752004-06-25 16:05:06 +0000[diff] [blame]1200ways. For example, it could be generated as a series of chained conditional
1201branches or with a lookup table.</p>
Chris Lattnerc88c17b2004-02-24 04:54:45 +0000[diff] [blame]1202
1203<h5>Example:</h5>
1204
1205<pre>
1206 <i>; Emulate a conditional br instruction</i>
1207 %Val = <a href="#i_cast">cast</a> bool %value to int
1208 switch int %Val, label %truedest [int 0, label %falsedest ]
1209
1210 <i>; Emulate an unconditional br instruction</i>
1211 switch uint 0, label %dest [ ]
1212
1213 <i>; Implement a jump table:</i>
1214 switch uint %val, label %otherwise [ uint 0, label %onzero
1215 uint 1, label %onone
1216 uint 2, label %ontwo ]
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1217</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1218</div>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1219
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1220<!-- _______________________________________________________________________ -->
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1221<div class="doc_subsubsection">
1222 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1223</div>
1224
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1225<div class="doc_text">
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1226
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1227<h5>Syntax:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1228
1229<pre>
1230 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
1231 to label &lt;normal label&gt; except label &lt;exception label&gt;
1232</pre>
1233
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1234<h5>Overview:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1235
1236<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1237function, with the possibility of control flow transfer to either the
1238'<tt>normal</tt>' <tt>label</tt> label or the
1239'<tt>exception</tt>'<tt>label</tt>. If the callee function returns with the
1240"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1241"normal" label. If the callee (or any indirect callees) returns with the "<a
1242href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted, and
1243continued at the dynamically nearest "except" label.</p>
1244
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1245<h5>Arguments:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1246
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1247<p>This instruction requires several arguments:</p>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1248
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1249<ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1250 <li>
1251 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
1252 convention</a> the call should use. If none is specified, the call defaults
1253 to using C calling conventions.
1254 </li>
1255 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1256 function value being invoked. In most cases, this is a direct function
1257 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1258 an arbitrary pointer to function value.
1259 </li>
1260
1261 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1262 function to be invoked. </li>
1263
1264 <li>'<tt>function args</tt>': argument list whose types match the function
1265 signature argument types. If the function signature indicates the function
1266 accepts a variable number of arguments, the extra arguments can be
1267 specified. </li>
1268
1269 <li>'<tt>normal label</tt>': the label reached when the called function
1270 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1271
1272 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1273 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1274
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1275</ol>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1276
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1277<h5>Semantics:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1278
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1279<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1280href="#i_call">call</a></tt>' instruction in most regards. The primary
1281difference is that it establishes an association with a label, which is used by
1282the runtime library to unwind the stack.</p>
1283
1284<p>This instruction is used in languages with destructors to ensure that proper
1285cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1286exception. Additionally, this is important for implementation of
1287'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1288
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1289<h5>Example:</h5>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]1290<pre>
1291 %retval = invoke int %Test(int 15) to label %Continue
1292 except label %TestCleanup <i>; {int}:retval set</i>
1293 %retval = invoke <a href="#callingconv">coldcc</a> int %Test(int 15) to label %Continue
1294 except label %TestCleanup <i>; {int}:retval set</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1295</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1296</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1297
1298
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1299<!-- _______________________________________________________________________ -->
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1300
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1301<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1302Instruction</a> </div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1303
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1304<div class="doc_text">
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1305
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1306<h5>Syntax:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1307<pre>
1308 unwind
1309</pre>
1310
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1311<h5>Overview:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1312
1313<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1314at the first callee in the dynamic call stack which used an <a
1315href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1316primarily used to implement exception handling.</p>
1317
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1318<h5>Semantics:</h5>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1319
1320<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1321immediately halt. The dynamic call stack is then searched for the first <a
1322href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1323execution continues at the "exceptional" destination block specified by the
1324<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1325dynamic call chain, undefined behavior results.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1326</div>
Chris Lattner35eca582004-10-16 18:04:13 +0000[diff] [blame]1327
1328<!-- _______________________________________________________________________ -->
1329
1330<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1331Instruction</a> </div>
1332
1333<div class="doc_text">
1334
1335<h5>Syntax:</h5>
1336<pre>
1337 unreachable
1338</pre>
1339
1340<h5>Overview:</h5>
1341
1342<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1343instruction is used to inform the optimizer that a particular portion of the
1344code is not reachable. This can be used to indicate that the code after a
1345no-return function cannot be reached, and other facts.</p>
1346
1347<h5>Semantics:</h5>
1348
1349<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1350</div>
1351
1352
1353
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1354<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1355<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1356<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1357<p>Binary operators are used to do most of the computation in a
1358program. They require two operands, execute an operation on them, and
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1359produce a single value. The operands might represent
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1360multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1361The result value of a binary operator is not
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1362necessarily the same type as its operands.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1363<p>There are several different binary operators:</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1364</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1365<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1366<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1367Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1368<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1369<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1370<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1371</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1372<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1373<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1374<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1375<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1376 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1377 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1378Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1379<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1380<p>The value produced is the integer or floating point sum of the two
1381operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1382<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1383<pre> &lt;result&gt; = add int 4, %var <i>; yields {int}:result = 4 + %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1384</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1385</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1386<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1387<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1388Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1389<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1390<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1391<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1392</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1393<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1394<p>The '<tt>sub</tt>' instruction returns the difference of its two
1395operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1396<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1397instruction present in most other intermediate representations.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1398<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1399<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1400 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1401values.
1402This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1403Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1404<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1405<p>The value produced is the integer or floating point difference of
1406the two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1407<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1408<pre> &lt;result&gt; = sub int 4, %var <i>; yields {int}:result = 4 - %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1409 &lt;result&gt; = sub int 0, %val <i>; yields {int}:result = -%var</i>
1410</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1411</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1412<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1413<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1414Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1415<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1416<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1417<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1418</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1419<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1420<p>The '<tt>mul</tt>' instruction returns the product of its two
1421operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1422<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1423<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1424 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1425values.
1426This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1427Both arguments must have identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1428<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1429<p>The value produced is the integer or floating point product of the
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1430two operands.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1431<p>There is no signed vs unsigned multiplication. The appropriate
1432action is taken based on the type of the operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1433<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1434<pre> &lt;result&gt; = mul int 4, %var <i>; yields {int}:result = 4 * %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1435</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1436</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1437<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1438<div class="doc_subsubsection"> <a name="i_div">'<tt>div</tt>'
1439Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1440<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1441<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1442<pre> &lt;result&gt; = div &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1443</pre>
1444<h5>Overview:</h5>
1445<p>The '<tt>div</tt>' instruction returns the quotient of its two
1446operands.</p>
1447<h5>Arguments:</h5>
1448<p>The two arguments to the '<tt>div</tt>' instruction must be either <a
1449 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1450values.
1451This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1452Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1453<h5>Semantics:</h5>
1454<p>The value produced is the integer or floating point quotient of the
1455two operands.</p>
1456<h5>Example:</h5>
1457<pre> &lt;result&gt; = div int 4, %var <i>; yields {int}:result = 4 / %var</i>
1458</pre>
1459</div>
1460<!-- _______________________________________________________________________ -->
1461<div class="doc_subsubsection"> <a name="i_rem">'<tt>rem</tt>'
1462Instruction</a> </div>
1463<div class="doc_text">
1464<h5>Syntax:</h5>
1465<pre> &lt;result&gt; = rem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1466</pre>
1467<h5>Overview:</h5>
1468<p>The '<tt>rem</tt>' instruction returns the remainder from the
1469division of its two operands.</p>
1470<h5>Arguments:</h5>
1471<p>The two arguments to the '<tt>rem</tt>' instruction must be either <a
1472 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnera58561b2004-08-12 19:12:28 +0000[diff] [blame]1473values.
1474This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1475Both arguments must have identical types.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1476<h5>Semantics:</h5>
1477<p>This returns the <i>remainder</i> of a division (where the result
1478has the same sign as the divisor), not the <i>modulus</i> (where the
1479result has the same sign as the dividend) of a value. For more
1480information about the difference, see: <a
1481 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1482Math Forum</a>.</p>
1483<h5>Example:</h5>
1484<pre> &lt;result&gt; = rem int 4, %var <i>; yields {int}:result = 4 % %var</i>
1485</pre>
1486</div>
1487<!-- _______________________________________________________________________ -->
1488<div class="doc_subsubsection"> <a name="i_setcc">'<tt>set<i>cc</i></tt>'
1489Instructions</a> </div>
1490<div class="doc_text">
1491<h5>Syntax:</h5>
1492<pre> &lt;result&gt; = seteq &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1493 &lt;result&gt; = setne &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1494 &lt;result&gt; = setlt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1495 &lt;result&gt; = setgt &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1496 &lt;result&gt; = setle &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1497 &lt;result&gt; = setge &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
1498</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1499<h5>Overview:</h5>
1500<p>The '<tt>set<i>cc</i></tt>' family of instructions returns a boolean
1501value based on a comparison of their two operands.</p>
1502<h5>Arguments:</h5>
1503<p>The two arguments to the '<tt>set<i>cc</i></tt>' instructions must
1504be of <a href="#t_firstclass">first class</a> type (it is not possible
1505to compare '<tt>label</tt>'s, '<tt>array</tt>'s, '<tt>structure</tt>'
1506or '<tt>void</tt>' values, etc...). Both arguments must have identical
1507types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1508<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1509<p>The '<tt>seteq</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1510value if both operands are equal.<br>
1511The '<tt>setne</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1512value if both operands are unequal.<br>
1513The '<tt>setlt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1514value if the first operand is less than the second operand.<br>
1515The '<tt>setgt</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1516value if the first operand is greater than the second operand.<br>
1517The '<tt>setle</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1518value if the first operand is less than or equal to the second operand.<br>
1519The '<tt>setge</tt>' instruction yields a <tt>true</tt> '<tt>bool</tt>'
1520value if the first operand is greater than or equal to the second
1521operand.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1522<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1523<pre> &lt;result&gt; = seteq int 4, 5 <i>; yields {bool}:result = false</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1524 &lt;result&gt; = setne float 4, 5 <i>; yields {bool}:result = true</i>
1525 &lt;result&gt; = setlt uint 4, 5 <i>; yields {bool}:result = true</i>
1526 &lt;result&gt; = setgt sbyte 4, 5 <i>; yields {bool}:result = false</i>
1527 &lt;result&gt; = setle sbyte 4, 5 <i>; yields {bool}:result = true</i>
1528 &lt;result&gt; = setge sbyte 4, 5 <i>; yields {bool}:result = false</i>
1529</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1530</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1531<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1532<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1533Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1534<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1535<p>Bitwise binary operators are used to do various forms of
1536bit-twiddling in a program. They are generally very efficient
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1537instructions and can commonly be strength reduced from other
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1538instructions. They require two operands, execute an operation on them,
1539and produce a single value. The resulting value of the bitwise binary
1540operators is always the same type as its first operand.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1541</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1542<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1543<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1544Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1545<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1546<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1547<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1548</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1549<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1550<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1551its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1552<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1553<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1554 href="#t_integral">integral</a> values. Both arguments must have
1555identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1556<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1557<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1558<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1559<div style="align: center">
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1560<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1561 <tbody>
1562 <tr>
1563 <td>In0</td>
1564 <td>In1</td>
1565 <td>Out</td>
1566 </tr>
1567 <tr>
1568 <td>0</td>
1569 <td>0</td>
1570 <td>0</td>
1571 </tr>
1572 <tr>
1573 <td>0</td>
1574 <td>1</td>
1575 <td>0</td>
1576 </tr>
1577 <tr>
1578 <td>1</td>
1579 <td>0</td>
1580 <td>0</td>
1581 </tr>
1582 <tr>
1583 <td>1</td>
1584 <td>1</td>
1585 <td>1</td>
1586 </tr>
1587 </tbody>
1588</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1589</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1590<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1591<pre> &lt;result&gt; = and int 4, %var <i>; yields {int}:result = 4 &amp; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1592 &lt;result&gt; = and int 15, 40 <i>; yields {int}:result = 8</i>
1593 &lt;result&gt; = and int 4, 8 <i>; yields {int}:result = 0</i>
1594</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1595</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1596<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1597<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1598<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1599<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1600<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1601</pre>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1602<h5>Overview:</h5>
1603<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1604or of its two operands.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1605<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1606<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1607 href="#t_integral">integral</a> values. Both arguments must have
1608identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1609<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1610<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1611<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1612<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1613<table border="1" cellspacing="0" cellpadding="4">
1614 <tbody>
1615 <tr>
1616 <td>In0</td>
1617 <td>In1</td>
1618 <td>Out</td>
1619 </tr>
1620 <tr>
1621 <td>0</td>
1622 <td>0</td>
1623 <td>0</td>
1624 </tr>
1625 <tr>
1626 <td>0</td>
1627 <td>1</td>
1628 <td>1</td>
1629 </tr>
1630 <tr>
1631 <td>1</td>
1632 <td>0</td>
1633 <td>1</td>
1634 </tr>
1635 <tr>
1636 <td>1</td>
1637 <td>1</td>
1638 <td>1</td>
1639 </tr>
1640 </tbody>
1641</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1642</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1643<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1644<pre> &lt;result&gt; = or int 4, %var <i>; yields {int}:result = 4 | %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1645 &lt;result&gt; = or int 15, 40 <i>; yields {int}:result = 47</i>
1646 &lt;result&gt; = or int 4, 8 <i>; yields {int}:result = 12</i>
1647</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1648</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1649<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1650<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
1651Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1652<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1653<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1654<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1655</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1656<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1657<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
1658or of its two operands. The <tt>xor</tt> is used to implement the
1659"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1660<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1661<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1662 href="#t_integral">integral</a> values. Both arguments must have
1663identical types.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1664<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1665<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1666<p> </p>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1667<div style="align: center">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1668<table border="1" cellspacing="0" cellpadding="4">
1669 <tbody>
1670 <tr>
1671 <td>In0</td>
1672 <td>In1</td>
1673 <td>Out</td>
1674 </tr>
1675 <tr>
1676 <td>0</td>
1677 <td>0</td>
1678 <td>0</td>
1679 </tr>
1680 <tr>
1681 <td>0</td>
1682 <td>1</td>
1683 <td>1</td>
1684 </tr>
1685 <tr>
1686 <td>1</td>
1687 <td>0</td>
1688 <td>1</td>
1689 </tr>
1690 <tr>
1691 <td>1</td>
1692 <td>1</td>
1693 <td>0</td>
1694 </tr>
1695 </tbody>
1696</table>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]1697</div>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1698<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1699<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1700<pre> &lt;result&gt; = xor int 4, %var <i>; yields {int}:result = 4 ^ %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1701 &lt;result&gt; = xor int 15, 40 <i>; yields {int}:result = 39</i>
1702 &lt;result&gt; = xor int 4, 8 <i>; yields {int}:result = 12</i>
Chris Lattner27f71f22003-09-03 00:41:47 +0000[diff] [blame]1703 &lt;result&gt; = xor int %V, -1 <i>; yields {int}:result = ~%V</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1704</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1705</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1706<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1707<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
1708Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1709<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1710<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1711<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1712</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1713<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1714<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
1715the left a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1717<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1718 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1719type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1720<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1721<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1722<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1723<pre> &lt;result&gt; = shl int 4, ubyte %var <i>; yields {int}:result = 4 &lt;&lt; %var</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1724 &lt;result&gt; = shl int 4, ubyte 2 <i>; yields {int}:result = 16</i>
1725 &lt;result&gt; = shl int 1, ubyte 10 <i>; yields {int}:result = 1024</i>
1726</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1727</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1728<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1729<div class="doc_subsubsection"> <a name="i_shr">'<tt>shr</tt>'
1730Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1731<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1732<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1733<pre> &lt;result&gt; = shr &lt;ty&gt; &lt;var1&gt;, ubyte &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1734</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1736<p>The '<tt>shr</tt>' instruction returns the first operand shifted to
1737the right a specified number of bits.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1739<p>The first argument to the '<tt>shr</tt>' instruction must be an <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1740 href="#t_integer">integer</a> type. The second argument must be an '<tt>ubyte</tt>'
1741type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1743<p>If the first argument is a <a href="#t_signed">signed</a> type, the
1744most significant bit is duplicated in the newly free'd bit positions.
1745If the first argument is unsigned, zero bits shall fill the empty
1746positions.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1747<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1748<pre> &lt;result&gt; = shr int 4, ubyte %var <i>; yields {int}:result = 4 &gt;&gt; %var</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1749 &lt;result&gt; = shr uint 4, ubyte 1 <i>; yields {uint}:result = 2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1750 &lt;result&gt; = shr int 4, ubyte 2 <i>; yields {int}:result = 1</i>
Chris Lattner8c6bb902003-06-18 21:30:51 +0000[diff] [blame]1751 &lt;result&gt; = shr sbyte 4, ubyte 3 <i>; yields {sbyte}:result = 0</i>
1752 &lt;result&gt; = shr sbyte -2, ubyte 1 <i>; yields {sbyte}:result = -1</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1753</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1754</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1755<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1756<div class="doc_subsection"> <a name="memoryops">Memory Access
1757Operations</a></div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1758<div class="doc_text">
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1759<p>A key design point of an SSA-based representation is how it
1760represents memory. In LLVM, no memory locations are in SSA form, which
1761makes things very simple. This section describes how to read, write,
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1762allocate, and free memory in LLVM.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1763</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1764<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1765<div class="doc_subsubsection"> <a name="i_malloc">'<tt>malloc</tt>'
1766Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1767<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1768<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1769<pre> &lt;result&gt; = malloc &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1770 &lt;result&gt; = malloc &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1771</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1772<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1773<p>The '<tt>malloc</tt>' instruction allocates memory from the system
1774heap and returns a pointer to it.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1775<h5>Arguments:</h5>
John Criswell6e4ca612004-02-24 16:13:56 +0000[diff] [blame]1776<p>The '<tt>malloc</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
1777bytes of memory from the operating system and returns a pointer of the
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1778appropriate type to the program. The second form of the instruction is
1779a shorter version of the first instruction that defaults to allocating
1780one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1781<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1782<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1783<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
1784a pointer is returned.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1785<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1786<pre> %array = malloc [4 x ubyte ] <i>; yields {[%4 x ubyte]*}:array</i>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1787
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1788 %size = <a
1789 href="#i_add">add</a> uint 2, 2 <i>; yields {uint}:size = uint 4</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1790 %array1 = malloc ubyte, uint 4 <i>; yields {ubyte*}:array1</i>
1791 %array2 = malloc [12 x ubyte], uint %size <i>; yields {[12 x ubyte]*}:array2</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1792</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1793</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1794<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1795<div class="doc_subsubsection"> <a name="i_free">'<tt>free</tt>'
1796Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1797<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1798<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1799<pre> free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1800</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1801<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1802<p>The '<tt>free</tt>' instruction returns memory back to the unused
1803memory heap, to be reallocated in the future.</p>
1804<p> </p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1805<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1806<p>'<tt>value</tt>' shall be a pointer value that points to a value
1807that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
1808instruction.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1809<h5>Semantics:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1810<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1811after this instruction executes.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1812<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1813<pre> %array = <a href="#i_malloc">malloc</a> [4 x ubyte] <i>; yields {[4 x ubyte]*}:array</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1814 free [4 x ubyte]* %array
1815</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1816</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1817<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1818<div class="doc_subsubsection"> <a name="i_alloca">'<tt>alloca</tt>'
1819Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1820<div class="doc_text">
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1821<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1822<pre> &lt;result&gt; = alloca &lt;type&gt;, uint &lt;NumElements&gt; <i>; yields {type*}:result</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1823 &lt;result&gt; = alloca &lt;type&gt; <i>; yields {type*}:result</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1824</pre>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1825<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1826<p>The '<tt>alloca</tt>' instruction allocates memory on the current
1827stack frame of the procedure that is live until the current function
1828returns to its caller.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Arguments:</h5>
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]1830<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1831bytes of memory on the runtime stack, returning a pointer of the
1832appropriate type to the program. The second form of the instruction is
1833a shorter version of the first that defaults to allocating one element.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1834<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1835<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1836<p>Memory is allocated, a pointer is returned. '<tt>alloca</tt>'d
1837memory is automatically released when the function returns. The '<tt>alloca</tt>'
1838instruction is commonly used to represent automatic variables that must
1839have an address available. When the function returns (either with the <tt><a
1840 href="#i_ret">ret</a></tt> or <tt><a href="#i_invoke">invoke</a></tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1841instructions), the memory is reclaimed.</p>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1842<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1843<pre> %ptr = alloca int <i>; yields {int*}:ptr</i>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1844 %ptr = alloca int, uint 4 <i>; yields {int*}:ptr</i>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1845</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1846</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1847<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1848<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
1849Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1850<div class="doc_text">
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1851<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1852<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;<br></pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1853<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1854<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1855<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1856<p>The argument to the '<tt>load</tt>' instruction specifies the memory
1857address to load from. The pointer must point to a <a
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1858 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1859marked as <tt>volatile</tt> then the optimizer is not allowed to modify
1860the number or order of execution of this <tt>load</tt> with other
1861volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
1862instructions. </p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1863<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1864<p>The location of memory pointed to is loaded.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1865<h5>Examples:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1866<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1867 <a
1868 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1869 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1870</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1871</div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1872<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1873<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
1874Instruction</a> </div>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1875<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1876<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattnerf0651072003-09-08 18:27:49 +0000[diff] [blame]1877 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1878</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1879<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1880<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1881<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1882<p>There are two arguments to the '<tt>store</tt>' instruction: a value
1883to store and an address to store it into. The type of the '<tt>&lt;pointer&gt;</tt>'
1884operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
1885operand. If the <tt>store</tt> is marked as <tt>volatile</tt> then the
1886optimizer is not allowed to modify the number or order of execution of
1887this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
1888 href="#i_store">store</a></tt> instructions.</p>
1889<h5>Semantics:</h5>
1890<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
1891at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1892<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1893<pre> %ptr = <a href="#i_alloca">alloca</a> int <i>; yields {int*}:ptr</i>
1894 <a
1895 href="#i_store">store</a> int 3, int* %ptr <i>; yields {void}</i>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1896 %val = load int* %ptr <i>; yields {int}:val = int 3</i>
1897</pre>
Chris Lattner2b7d3202002-05-06 03:03:22 +0000[diff] [blame]1898<!-- _______________________________________________________________________ -->
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1899<div class="doc_subsubsection">
1900 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
1901</div>
1902
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1903<div class="doc_text">
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1904<h5>Syntax:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1905<pre>
1906 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
1907</pre>
1908
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1909<h5>Overview:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1910
1911<p>
1912The '<tt>getelementptr</tt>' instruction is used to get the address of a
1913subelement of an aggregate data structure.</p>
1914
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1915<h5>Arguments:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1916
1917<p>This instruction takes a list of integer constants that indicate what
1918elements of the aggregate object to index to. The actual types of the arguments
1919provided depend on the type of the first pointer argument. The
1920'<tt>getelementptr</tt>' instruction is used to index down through the type
1921levels of a structure. When indexing into a structure, only <tt>uint</tt>
1922integer constants are allowed. When indexing into an array or pointer
1923<tt>int</tt> and <tt>long</tt> indexes are allowed of any sign.</p>
1924
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1925<p>For example, let's consider a C code fragment and how it gets
1926compiled to LLVM:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1927
1928<pre>
1929 struct RT {
1930 char A;
1931 int B[10][20];
1932 char C;
1933 };
1934 struct ST {
1935 int X;
1936 double Y;
1937 struct RT Z;
1938 };
1939
1940 int *foo(struct ST *s) {
1941 return &amp;s[1].Z.B[5][13];
1942 }
1943</pre>
1944
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1945<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1946
1947<pre>
1948 %RT = type { sbyte, [10 x [20 x int]], sbyte }
1949 %ST = type { int, double, %RT }
1950
Brian Gaeke7283e7c2004-07-02 21:08:14 +0000[diff] [blame]1951 implementation
1952
1953 int* %foo(%ST* %s) {
1954 entry:
1955 %reg = getelementptr %ST* %s, int 1, uint 2, uint 1, int 5, int 13
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1956 ret int* %reg
1957 }
1958</pre>
1959
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1960<h5>Semantics:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1961
1962<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
Chris Lattnere53e5082004-06-03 22:57:15 +0000[diff] [blame]1963on the pointer type that is being index into. <a href="#t_pointer">Pointer</a>
1964and <a href="#t_array">array</a> types require <tt>uint</tt>, <tt>int</tt>,
1965<tt>ulong</tt>, or <tt>long</tt> values, and <a href="#t_struct">structure</a>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1966types require <tt>uint</tt> <b>constants</b>.</p>
1967
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]1968<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1969type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ int, double, %RT
1970}</tt>' type, a structure. The second index indexes into the third element of
1971the structure, yielding a '<tt>%RT</tt>' = '<tt>{ sbyte, [10 x [20 x int]],
1972sbyte }</tt>' type, another structure. The third index indexes into the second
1973element of the structure, yielding a '<tt>[10 x [20 x int]]</tt>' type, an
1974array. The two dimensions of the array are subscripted into, yielding an
1975'<tt>int</tt>' type. The '<tt>getelementptr</tt>' instruction return a pointer
1976to this element, thus computing a value of '<tt>int*</tt>' type.</p>
1977
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]1978<p>Note that it is perfectly legal to index partially through a
1979structure, returning a pointer to an inner element. Because of this,
1980the LLVM code for the given testcase is equivalent to:</p>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1981
1982<pre>
Chris Lattnerd4f6b172005-03-07 22:13:59 +0000[diff] [blame]1983 int* %foo(%ST* %s) {
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1984 %t1 = getelementptr %ST* %s, int 1 <i>; yields %ST*:%t1</i>
1985 %t2 = getelementptr %ST* %t1, int 0, uint 2 <i>; yields %RT*:%t2</i>
1986 %t3 = getelementptr %RT* %t2, int 0, uint 1 <i>; yields [10 x [20 x int]]*:%t3</i>
1987 %t4 = getelementptr [10 x [20 x int]]* %t3, int 0, int 5 <i>; yields [20 x int]*:%t4</i>
1988 %t5 = getelementptr [20 x int]* %t4, int 0, int 13 <i>; yields int*:%t5</i>
1989 ret int* %t5
1990 }
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]1991</pre>
Chris Lattner7faa8832002-04-14 06:13:44 +0000[diff] [blame]1992<h5>Example:</h5>
Chris Lattnerf74d5c72004-04-05 01:30:49 +0000[diff] [blame]1993<pre>
1994 <i>; yields [12 x ubyte]*:aptr</i>
1995 %aptr = getelementptr {int, [12 x ubyte]}* %sptr, long 0, uint 1
1996</pre>
1997
1998</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]1999<!-- ======================================================================= -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2000<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2001<div class="doc_text">
John Criswell4457dc92004-04-09 16:48:45 +0000[diff] [blame]2002<p>The instructions in this category are the "miscellaneous"
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2003instructions, which defy better classification.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2004</div>
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2005<!-- _______________________________________________________________________ -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2006<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
2007Instruction</a> </div>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2008<div class="doc_text">
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2009<h5>Syntax:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2010<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2011<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2012<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
2013the SSA graph representing the function.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2014<h5>Arguments:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2015<p>The type of the incoming values are specified with the first type
2016field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
2017as arguments, with one pair for each predecessor basic block of the
2018current block. Only values of <a href="#t_firstclass">first class</a>
2019type may be used as the value arguments to the PHI node. Only labels
2020may be used as the label arguments.</p>
2021<p>There must be no non-phi instructions between the start of a basic
2022block and the PHI instructions: i.e. PHI instructions must be first in
2023a basic block.</p>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2024<h5>Semantics:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2025<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
2026value specified by the parameter, depending on which basic block we
2027came from in the last <a href="#terminators">terminator</a> instruction.</p>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2028<h5>Example:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2029<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi uint [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add uint %indvar, 1<br> br label %Loop<br></pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2030</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2031
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2032<!-- _______________________________________________________________________ -->
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2033<div class="doc_subsubsection">
2034 <a name="i_cast">'<tt>cast .. to</tt>' Instruction</a>
2035</div>
2036
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2037<div class="doc_text">
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2038
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2039<h5>Syntax:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2040
2041<pre>
2042 &lt;result&gt; = cast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2043</pre>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2044
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2045<h5>Overview:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2046
2047<p>
2048The '<tt>cast</tt>' instruction is used as the primitive means to convert
2049integers to floating point, change data type sizes, and break type safety (by
2050casting pointers).
2051</p>
2052
2053
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2054<h5>Arguments:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2055
2056<p>
2057The '<tt>cast</tt>' instruction takes a value to cast, which must be a first
2058class value, and a type to cast it to, which must also be a <a
2059href="#t_firstclass">first class</a> type.
2060</p>
2061
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2062<h5>Semantics:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2063
2064<p>
2065This instruction follows the C rules for explicit casts when determining how the
2066data being cast must change to fit in its new container.
2067</p>
2068
2069<p>
2070When casting to bool, any value that would be considered true in the context of
2071a C '<tt>if</tt>' condition is converted to the boolean '<tt>true</tt>' values,
2072all else are '<tt>false</tt>'.
2073</p>
2074
2075<p>
2076When extending an integral value from a type of one signness to another (for
2077example '<tt>sbyte</tt>' to '<tt>ulong</tt>'), the value is sign-extended if the
2078<b>source</b> value is signed, and zero-extended if the source value is
2079unsigned. <tt>bool</tt> values are always zero extended into either zero or
2080one.
2081</p>
2082
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2083<h5>Example:</h5>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2084
2085<pre>
2086 %X = cast int 257 to ubyte <i>; yields ubyte:1</i>
Chris Lattner7bae3952002-06-25 18:03:17 +0000[diff] [blame]2087 %Y = cast int 123 to bool <i>; yields bool:true</i>
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2088</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2089</div>
Chris Lattnercc37aae2004-03-12 05:50:16 +0000[diff] [blame]2090
2091<!-- _______________________________________________________________________ -->
2092<div class="doc_subsubsection">
2093 <a name="i_select">'<tt>select</tt>' Instruction</a>
2094</div>
2095
2096<div class="doc_text">
2097
2098<h5>Syntax:</h5>
2099
2100<pre>
2101 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
2102</pre>
2103
2104<h5>Overview:</h5>
2105
2106<p>
2107The '<tt>select</tt>' instruction is used to choose one value based on a
2108condition, without branching.
2109</p>
2110
2111
2112<h5>Arguments:</h5>
2113
2114<p>
2115The '<tt>select</tt>' instruction requires a boolean value indicating the condition, and two values of the same <a href="#t_firstclass">first class</a> type.
2116</p>
2117
2118<h5>Semantics:</h5>
2119
2120<p>
2121If the boolean condition evaluates to true, the instruction returns the first
2122value argument, otherwise it returns the second value argument.
2123</p>
2124
2125<h5>Example:</h5>
2126
2127<pre>
2128 %X = select bool true, ubyte 17, ubyte 42 <i>; yields ubyte:17</i>
2129</pre>
2130</div>
2131
2132
2133
2134
2135
Chris Lattner33ba0d92001-07-09 00:26:23 +0000[diff] [blame]2136<!-- _______________________________________________________________________ -->
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2137<div class="doc_subsubsection">
2138 <a name="i_call">'<tt>call</tt>' Instruction</a>
2139</div>
2140
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2141<div class="doc_text">
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2142
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2143<h5>Syntax:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2144<pre>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2145 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2146</pre>
2147
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2148<h5>Overview:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2149
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2150<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2151
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2152<h5>Arguments:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2153
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2154<p>This instruction requires several arguments:</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2155
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2156<ol>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2157 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2158 <p>The optional "tail" marker indicates whether the callee function accesses
2159 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2160 function call is eligible for tail call optimization. Note that calls may
2161 be marked "tail" even if they do not occur before a <a
2162 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2163 </li>
2164 <li>
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2165 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
2166 convention</a> the call should use. If none is specified, the call defaults
2167 to using C calling conventions.
2168 </li>
2169 <li>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2170 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
2171 being invoked. The argument types must match the types implied by this
2172 signature.</p>
2173 </li>
2174 <li>
2175 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
2176 be invoked. In most cases, this is a direct function invocation, but
2177 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
2178 to function values.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2179 </li>
2180 <li>
2181 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencera7e302a2005-05-01 22:22:57 +0000[diff] [blame]2182 function signature argument types. All arguments must be of
2183 <a href="#t_firstclass">first class</a> type. If the function signature
2184 indicates the function accepts a variable number of arguments, the extra
2185 arguments can be specified.</p>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2186 </li>
Chris Lattner6536cfe2002-05-06 22:08:29 +0000[diff] [blame]2187</ol>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2188
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2189<h5>Semantics:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2190
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2191<p>The '<tt>call</tt>' instruction is used to cause control flow to
2192transfer to a specified function, with its incoming arguments bound to
2193the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
2194instruction in the called function, control flow continues with the
2195instruction after the function call, and the return value of the
2196function is bound to the result argument. This is a simpler case of
2197the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2198
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]2199<h5>Example:</h5>
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2200
2201<pre>
2202 %retval = call int %test(int %argc)
2203 call int(sbyte*, ...) *%printf(sbyte* %msg, int 12, sbyte 42);
2204 %X = tail call int %foo()
Chris Lattnerbad10ee2005-05-06 22:57:40 +0000[diff] [blame]2205 %Y = tail call <a href="#callingconv">fastcc</a> int %foo()
Chris Lattner2bff5242005-05-06 05:47:36 +0000[diff] [blame]2206</pre>
2207
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2208</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2209
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2210<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2211<div class="doc_subsubsection">
2212 <a name="i_vanext">'<tt>vanext</tt>' Instruction</a>
2213</div>
2214
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2215<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2216
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2217<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2218
2219<pre>
2220 &lt;resultarglist&gt; = vanext &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2221</pre>
2222
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2223<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2224
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2225<p>The '<tt>vanext</tt>' instruction is used to access arguments passed
2226through the "variable argument" area of a function call. It is used to
2227implement the <tt>va_arg</tt> macro in C.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2228
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2229<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2230
2231<p>This instruction takes a <tt>va_list</tt> value and the type of the
2232argument. It returns another <tt>va_list</tt>. The actual type of
2233<tt>va_list</tt> may be defined differently for different targets. Most targets
2234use a <tt>va_list</tt> type of <tt>sbyte*</tt> or some other pointer type.</p>
2235
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2236<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2237
2238<p>The '<tt>vanext</tt>' instruction advances the specified <tt>va_list</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2239past an argument of the specified type. In conjunction with the <a
2240 href="#i_vaarg"><tt>vaarg</tt></a> instruction, it is used to implement
2241the <tt>va_arg</tt> macro available in C. For more information, see
2242the variable argument handling <a href="#int_varargs">Intrinsic
2243Functions</a>.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2244
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2245<p>It is legal for this instruction to be called in a function which
2246does not take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2247function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2248
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2249<p><tt>vanext</tt> is an LLVM instruction instead of an <a
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2250href="#intrinsics">intrinsic function</a> because it takes a type as an
2251argument. The type refers to the current argument in the <tt>va_list</tt>, it
2252tells the compiler how far on the stack it needs to advance to find the next
2253argument</p>
2254
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2255<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2256
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2257<p>See the <a href="#int_varargs">variable argument processing</a>
2258section.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2259
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2260</div>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2261
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2262<!-- _______________________________________________________________________ -->
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2263<div class="doc_subsubsection">
2264 <a name="i_vaarg">'<tt>vaarg</tt>' Instruction</a>
2265</div>
2266
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2267<div class="doc_text">
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2268
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2269<h5>Syntax:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2270
2271<pre>
2272 &lt;resultval&gt; = vaarg &lt;va_list&gt; &lt;arglist&gt;, &lt;argty&gt;
2273</pre>
2274
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2275<h5>Overview:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2276
2277<p>The '<tt>vaarg</tt>' instruction is used to access arguments passed through
2278the "variable argument" area of a function call. It is used to implement the
2279<tt>va_arg</tt> macro in C.</p>
2280
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2281<h5>Arguments:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2282
2283<p>This instruction takes a <tt>va_list</tt> value and the type of the
2284argument. It returns a value of the specified argument type. Again, the actual
2285type of <tt>va_list</tt> is target specific.</p>
2286
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2287<h5>Semantics:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2288
2289<p>The '<tt>vaarg</tt>' instruction loads an argument of the specified type from
2290the specified <tt>va_list</tt>. In conjunction with the <a
2291href="#i_vanext"><tt>vanext</tt></a> instruction, it is used to implement the
2292<tt>va_arg</tt> macro available in C. For more information, see the variable
2293argument handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
2294
2295<p>It is legal for this instruction to be called in a function which does not
2296take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2297function.</p>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2298
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2299<p><tt>vaarg</tt> is an LLVM instruction instead of an <a
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2300href="#intrinsics">intrinsic function</a> because it takes an type as an
2301argument.</p>
2302
Chris Lattner8d1a81d2003-10-18 05:51:36 +0000[diff] [blame]2303<h5>Example:</h5>
Chris Lattnere19d7a72004-09-27 21:51:25 +0000[diff] [blame]2304
2305<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
2306
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2307</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2308
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2309<!-- *********************************************************************** -->
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2310<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
2311<!-- *********************************************************************** -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2312
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2313<div class="doc_text">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2314
2315<p>LLVM supports the notion of an "intrinsic function". These functions have
2316well known names and semantics, and are required to follow certain
2317restrictions. Overall, these instructions represent an extension mechanism for
2318the LLVM language that does not require changing all of the transformations in
2319LLVM to add to the language (or the bytecode reader/writer, the parser,
2320etc...).</p>
2321
2322<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix, this
2323prefix is reserved in LLVM for intrinsic names, thus functions may not be named
2324this. Intrinsic functions must always be external functions: you cannot define
2325the body of intrinsic functions. Intrinsic functions may only be used in call
2326or invoke instructions: it is illegal to take the address of an intrinsic
2327function. Additionally, because intrinsic functions are part of the LLVM
2328language, it is required that they all be documented here if any are added.</p>
2329
2330
2331<p>
2332Adding an intrinsic to LLVM is straight-forward if it is possible to express the
2333concept in LLVM directly (ie, code generator support is not _required_). To do
2334this, extend the default implementation of the IntrinsicLowering class to handle
2335the intrinsic. Code generators use this class to lower intrinsics they do not
2336understand to raw LLVM instructions that they do.
2337</p>
2338
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2339</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2340
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2341<!-- ======================================================================= -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2342<div class="doc_subsection">
2343 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
2344</div>
2345
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2346<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2347
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2348<p>Variable argument support is defined in LLVM with the <a
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2349 href="#i_vanext"><tt>vanext</tt></a> instruction and these three
2350intrinsic functions. These functions are related to the similarly
2351named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2352
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2353<p>All of these functions operate on arguments that use a
2354target-specific value type "<tt>va_list</tt>". The LLVM assembly
2355language reference manual does not define what this type is, so all
2356transformations should be prepared to handle intrinsics with any type
2357used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2358
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2359<p>This example shows how the <a href="#i_vanext"><tt>vanext</tt></a>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2360instruction and the variable argument handling intrinsic functions are
2361used.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2362
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2363<pre>
2364int %test(int %X, ...) {
2365 ; Initialize variable argument processing
2366 %ap = call sbyte* %<a href="#i_va_start">llvm.va_start</a>()
2367
2368 ; Read a single integer argument
2369 %tmp = vaarg sbyte* %ap, int
2370
2371 ; Advance to the next argument
2372 %ap2 = vanext sbyte* %ap, int
2373
2374 ; Demonstrate usage of llvm.va_copy and llvm.va_end
2375 %aq = call sbyte* %<a href="#i_va_copy">llvm.va_copy</a>(sbyte* %ap2)
2376 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %aq)
2377
2378 ; Stop processing of arguments.
2379 call void %<a href="#i_va_end">llvm.va_end</a>(sbyte* %ap2)
2380 ret int %tmp
2381}
2382</pre>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2383</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2384
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2385<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2386<div class="doc_subsubsection">
2387 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
2388</div>
2389
2390
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2391<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2392<h5>Syntax:</h5>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2393<pre> declare &lt;va_list&gt; %llvm.va_start()<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2394<h5>Overview:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2395<p>The '<tt>llvm.va_start</tt>' intrinsic returns a new <tt>&lt;arglist&gt;</tt>
2396for subsequent use by the variable argument intrinsics.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2397<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2398<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2399macro available in C. In a target-dependent way, it initializes and
2400returns a <tt>va_list</tt> element, so that the next <tt>vaarg</tt>
2401will produce the first variable argument passed to the function. Unlike
2402the C <tt>va_start</tt> macro, this intrinsic does not need to know the
2403last argument of the function, the compiler can figure that out.</p>
2404<p>Note that this intrinsic function is only legal to be called from
2405within the body of a variable argument function.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2406</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2407
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2408<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2409<div class="doc_subsubsection">
2410 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
2411</div>
2412
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2413<div class="doc_text">
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2414<h5>Syntax:</h5>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2415<pre> declare void %llvm.va_end(&lt;va_list&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2416<h5>Overview:</h5>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2417<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
2418which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
2419or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2420<h5>Arguments:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2421<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2422<h5>Semantics:</h5>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2423<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner261efe92003-11-25 01:02:51 +0000[diff] [blame]2424macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
2425Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
2426 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
2427with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2428</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2429
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2430<!-- _______________________________________________________________________ -->
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2431<div class="doc_subsubsection">
2432 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
2433</div>
2434
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2435<div class="doc_text">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2436
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2437<h5>Syntax:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2438
2439<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2440 declare &lt;va_list&gt; %llvm.va_copy(&lt;va_list&gt; &lt;destarglist&gt;)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2441</pre>
2442
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2443<h5>Overview:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2444
2445<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
2446from the source argument list to the destination argument list.</p>
2447
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2448<h5>Arguments:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2449
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2450<p>The argument is the <tt>va_list</tt> to copy.</p>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2451
Chris Lattnerd9ad5b32003-05-08 04:57:36 +0000[diff] [blame]2452<h5>Semantics:</h5>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2453
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2454<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2455macro available in C. In a target-dependent way, it copies the source
2456<tt>va_list</tt> element into the returned list. This intrinsic is necessary
Chris Lattnerfcd37252004-06-21 22:52:48 +0000[diff] [blame]2457because the <tt><a href="#i_va_start">llvm.va_start</a></tt> intrinsic may be
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2458arbitrarily complex and require memory allocation, for example.</p>
2459
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]2460</div>
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]2461
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2462<!-- ======================================================================= -->
2463<div class="doc_subsection">
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2464 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
2465</div>
2466
2467<div class="doc_text">
2468
2469<p>
2470LLVM support for <a href="GarbageCollection.html">Accurate Garbage
2471Collection</a> requires the implementation and generation of these intrinsics.
2472These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
2473stack</a>, as well as garbage collector implementations that require <a
2474href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
2475Front-ends for type-safe garbage collected languages should generate these
2476intrinsics to make use of the LLVM garbage collectors. For more details, see <a
2477href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
2478</p>
2479</div>
2480
2481<!-- _______________________________________________________________________ -->
2482<div class="doc_subsubsection">
2483 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
2484</div>
2485
2486<div class="doc_text">
2487
2488<h5>Syntax:</h5>
2489
2490<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2491 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2492</pre>
2493
2494<h5>Overview:</h5>
2495
John Criswell9e2485c2004-12-10 15:51:16 +0000[diff] [blame]2496<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2497the code generator, and allows some metadata to be associated with it.</p>
2498
2499<h5>Arguments:</h5>
2500
2501<p>The first argument specifies the address of a stack object that contains the
2502root pointer. The second pointer (which must be either a constant or a global
2503value address) contains the meta-data to be associated with the root.</p>
2504
2505<h5>Semantics:</h5>
2506
2507<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
2508location. At compile-time, the code generator generates information to allow
2509the runtime to find the pointer at GC safe points.
2510</p>
2511
2512</div>
2513
2514
2515<!-- _______________________________________________________________________ -->
2516<div class="doc_subsubsection">
2517 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
2518</div>
2519
2520<div class="doc_text">
2521
2522<h5>Syntax:</h5>
2523
2524<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2525 declare sbyte* %llvm.gcread(sbyte** %Ptr)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2526</pre>
2527
2528<h5>Overview:</h5>
2529
2530<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
2531locations, allowing garbage collector implementations that require read
2532barriers.</p>
2533
2534<h5>Arguments:</h5>
2535
2536<p>The argument is the address to read from, which should be an address
2537allocated from the garbage collector.</p>
2538
2539<h5>Semantics:</h5>
2540
2541<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
2542instruction, but may be replaced with substantially more complex code by the
2543garbage collector runtime, as needed.</p>
2544
2545</div>
2546
2547
2548<!-- _______________________________________________________________________ -->
2549<div class="doc_subsubsection">
2550 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
2551</div>
2552
2553<div class="doc_text">
2554
2555<h5>Syntax:</h5>
2556
2557<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2558 declare void %llvm.gcwrite(sbyte* %P1, sbyte** %P2)
Chris Lattnerd7923912004-05-23 21:06:01 +0000[diff] [blame]2559</pre>
2560
2561<h5>Overview:</h5>
2562
2563<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
2564locations, allowing garbage collector implementations that require write
2565barriers (such as generational or reference counting collectors).</p>
2566
2567<h5>Arguments:</h5>
2568
2569<p>The first argument is the reference to store, and the second is the heap
2570location to store to.</p>
2571
2572<h5>Semantics:</h5>
2573
2574<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
2575instruction, but may be replaced with substantially more complex code by the
2576garbage collector runtime, as needed.</p>
2577
2578</div>
2579
2580
2581
2582<!-- ======================================================================= -->
2583<div class="doc_subsection">
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2584 <a name="int_codegen">Code Generator Intrinsics</a>
2585</div>
2586
2587<div class="doc_text">
2588<p>
2589These intrinsics are provided by LLVM to expose special features that may only
2590be implemented with code generator support.
2591</p>
2592
2593</div>
2594
2595<!-- _______________________________________________________________________ -->
2596<div class="doc_subsubsection">
2597 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
2598</div>
2599
2600<div class="doc_text">
2601
2602<h5>Syntax:</h5>
2603<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2604 declare void* %llvm.returnaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2605</pre>
2606
2607<h5>Overview:</h5>
2608
2609<p>
2610The '<tt>llvm.returnaddress</tt>' intrinsic returns a target-specific value
2611indicating the return address of the current function or one of its callers.
2612</p>
2613
2614<h5>Arguments:</h5>
2615
2616<p>
2617The argument to this intrinsic indicates which function to return the address
2618for. Zero indicates the calling function, one indicates its caller, etc. The
2619argument is <b>required</b> to be a constant integer value.
2620</p>
2621
2622<h5>Semantics:</h5>
2623
2624<p>
2625The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
2626the return address of the specified call frame, or zero if it cannot be
2627identified. The value returned by this intrinsic is likely to be incorrect or 0
2628for arguments other than zero, so it should only be used for debugging purposes.
2629</p>
2630
2631<p>
2632Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]2633aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2634source-language caller.
2635</p>
2636</div>
2637
2638
2639<!-- _______________________________________________________________________ -->
2640<div class="doc_subsubsection">
2641 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
2642</div>
2643
2644<div class="doc_text">
2645
2646<h5>Syntax:</h5>
2647<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2648 declare void* %llvm.frameaddress(uint &lt;level&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2649</pre>
2650
2651<h5>Overview:</h5>
2652
2653<p>
2654The '<tt>llvm.frameaddress</tt>' intrinsic returns the target-specific frame
2655pointer value for the specified stack frame.
2656</p>
2657
2658<h5>Arguments:</h5>
2659
2660<p>
2661The argument to this intrinsic indicates which function to return the frame
2662pointer for. Zero indicates the calling function, one indicates its caller,
2663etc. The argument is <b>required</b> to be a constant integer value.
2664</p>
2665
2666<h5>Semantics:</h5>
2667
2668<p>
2669The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
2670the frame address of the specified call frame, or zero if it cannot be
2671identified. The value returned by this intrinsic is likely to be incorrect or 0
2672for arguments other than zero, so it should only be used for debugging purposes.
2673</p>
2674
2675<p>
2676Note that calling this intrinsic does not prevent function inlining or other
Chris Lattnerb40bb382005-03-07 20:30:51 +0000[diff] [blame]2677aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2678source-language caller.
2679</p>
2680</div>
2681
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2682<!-- _______________________________________________________________________ -->
2683<div class="doc_subsubsection">
2684 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
2685</div>
2686
2687<div class="doc_text">
2688
2689<h5>Syntax:</h5>
2690<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2691 declare void %llvm.prefetch(sbyte * &lt;address&gt;,
2692 uint &lt;rw&gt;, uint &lt;locality&gt;)
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2693</pre>
2694
2695<h5>Overview:</h5>
2696
2697
2698<p>
2699The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
2700a prefetch instruction if supported, otherwise it is a noop. Prefetches have no
Chris Lattner2a615362005-02-28 19:47:14 +0000[diff] [blame]2701effect on the behavior of the program, but can change its performance
2702characteristics.
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2703</p>
2704
2705<h5>Arguments:</h5>
2706
2707<p>
2708<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
2709determining if the fetch should be for a read (0) or write (1), and
2710<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattneraeffb4a2005-03-07 20:31:38 +0000[diff] [blame]2711locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2712<tt>locality</tt> arguments must be constant integers.
2713</p>
2714
2715<h5>Semantics:</h5>
2716
2717<p>
2718This intrinsic does not modify the behavior of the program. In particular,
2719prefetches cannot trap and do not produce a value. On targets that support this
2720intrinsic, the prefetch can provide hints to the processor cache for better
2721performance.
2722</p>
2723
2724</div>
2725
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]2726<!-- _______________________________________________________________________ -->
2727<div class="doc_subsubsection">
2728 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
2729</div>
2730
2731<div class="doc_text">
2732
2733<h5>Syntax:</h5>
2734<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2735 declare void %llvm.pcmarker( uint &lt;id&gt; )
Andrew Lenharth7f4ec3b2005-03-28 20:05:49 +0000[diff] [blame]2736</pre>
2737
2738<h5>Overview:</h5>
2739
2740
2741<p>
2742The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a PC in a region of
2743code to simulators and other tools. The method is target specific, but it is
2744expected that the marker will use exported symbols to transmit the PC of the marker.
2745The marker makes no guaranties that it will remain with any specific instruction
2746after optimizations. It is possible that the presense of a marker will inhibit
2747optimizations. The intended use is to be inserted after optmizations to allow
2748corrolations of simulation runs.
2749</p>
2750
2751<h5>Arguments:</h5>
2752
2753<p>
2754<tt>id</tt> is a numerical id identifying the marker.
2755</p>
2756
2757<h5>Semantics:</h5>
2758
2759<p>
2760This intrinsic does not modify the behavior of the program. Backends that do not
2761support this intrinisic may ignore it.
2762</p>
2763
2764</div>
2765
Chris Lattner9a9d7ac2005-02-28 19:24:19 +0000[diff] [blame]2766
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2767<!-- ======================================================================= -->
2768<div class="doc_subsection">
2769 <a name="int_os">Operating System Intrinsics</a>
2770</div>
2771
2772<div class="doc_text">
2773<p>
2774These intrinsics are provided by LLVM to support the implementation of
2775operating system level code.
2776</p>
2777
2778</div>
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2779
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2780<!-- _______________________________________________________________________ -->
2781<div class="doc_subsubsection">
2782 <a name="i_readport">'<tt>llvm.readport</tt>' Intrinsic</a>
2783</div>
2784
2785<div class="doc_text">
2786
2787<h5>Syntax:</h5>
2788<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2789 declare &lt;integer type&gt; %llvm.readport (&lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2790</pre>
2791
2792<h5>Overview:</h5>
2793
2794<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2795The '<tt>llvm.readport</tt>' intrinsic reads data from the specified hardware
2796I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2797</p>
2798
2799<h5>Arguments:</h5>
2800
2801<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2802The argument to this intrinsic indicates the hardware I/O address from which
2803to read the data. The address is in the hardware I/O address namespace (as
2804opposed to being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2805</p>
2806
2807<h5>Semantics:</h5>
2808
2809<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2810The '<tt>llvm.readport</tt>' intrinsic reads data from the hardware I/O port
2811specified by <i>address</i> and returns the value. The address and return
2812value must be integers, but the size is dependent upon the platform upon which
2813the program is code generated. For example, on x86, the address must be an
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2814unsigned 16-bit value, and the return value must be 8, 16, or 32 bits.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2815</p>
2816
2817</div>
2818
2819<!-- _______________________________________________________________________ -->
2820<div class="doc_subsubsection">
2821 <a name="i_writeport">'<tt>llvm.writeport</tt>' Intrinsic</a>
2822</div>
2823
2824<div class="doc_text">
2825
2826<h5>Syntax:</h5>
2827<pre>
Chris Lattnerc3f59762004-12-09 17:30:23 +0000[diff] [blame]2828 call void (&lt;integer type&gt;, &lt;integer type&gt;)*
2829 %llvm.writeport (&lt;integer type&gt; &lt;value&gt;,
2830 &lt;integer type&gt; &lt;address&gt;)
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2831</pre>
2832
2833<h5>Overview:</h5>
2834
2835<p>
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2836The '<tt>llvm.writeport</tt>' intrinsic writes data to the specified hardware
2837I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2838</p>
2839
2840<h5>Arguments:</h5>
2841
2842<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2843The first argument is the value to write to the I/O port.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2844</p>
2845
2846<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2847The second argument indicates the hardware I/O address to which data should be
2848written. The address is in the hardware I/O address namespace (as opposed to
2849being a memory location for memory mapped I/O).
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2850</p>
2851
2852<h5>Semantics:</h5>
2853
2854<p>
2855The '<tt>llvm.writeport</tt>' intrinsic writes <i>value</i> to the I/O port
2856specified by <i>address</i>. The address and value must be integers, but the
2857size is dependent upon the platform upon which the program is code generated.
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2858For example, on x86, the address must be an unsigned 16-bit value, and the
John Criswell7123e272004-04-09 16:43:20 +0000[diff] [blame]2859value written must be 8, 16, or 32 bits in length.
John Criswellcfd3bac2004-04-09 15:23:37 +0000[diff] [blame]2860</p>
2861
2862</div>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2863
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2864<!-- _______________________________________________________________________ -->
2865<div class="doc_subsubsection">
2866 <a name="i_readio">'<tt>llvm.readio</tt>' Intrinsic</a>
2867</div>
2868
2869<div class="doc_text">
2870
2871<h5>Syntax:</h5>
2872<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2873 declare &lt;result&gt; %llvm.readio (&lt;ty&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2874</pre>
2875
2876<h5>Overview:</h5>
2877
2878<p>
2879The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
2880address.
2881</p>
2882
2883<h5>Arguments:</h5>
2884
2885<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2886The argument to this intrinsic is a pointer indicating the memory address from
2887which to read the data. The data must be a
2888<a href="#t_firstclass">first class</a> type.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2889</p>
2890
2891<h5>Semantics:</h5>
2892
2893<p>
2894The '<tt>llvm.readio</tt>' intrinsic reads data from a memory mapped I/O
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2895location specified by <i>pointer</i> and returns the value. The argument must
2896be a pointer, and the return value must be a
2897<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2898may not support I/O on all first class types. For example, 32-bit processors
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2899may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2900</p>
2901
2902<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2903This intrinsic enforces an in-order memory model for llvm.readio and
2904llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2905scheduled processors may execute loads and stores out of order, re-ordering at
2906run time accesses to memory mapped I/O registers. Using these intrinsics
2907ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2908</p>
2909
2910</div>
2911
2912<!-- _______________________________________________________________________ -->
2913<div class="doc_subsubsection">
2914 <a name="i_writeio">'<tt>llvm.writeio</tt>' Intrinsic</a>
2915</div>
2916
2917<div class="doc_text">
2918
2919<h5>Syntax:</h5>
2920<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]2921 declare void %llvm.writeio (&lt;ty1&gt; &lt;value&gt;, &lt;ty2&gt; * &lt;pointer&gt;)
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2922</pre>
2923
2924<h5>Overview:</h5>
2925
2926<p>
2927The '<tt>llvm.writeio</tt>' intrinsic writes data to the specified memory
2928mapped I/O address.
2929</p>
2930
2931<h5>Arguments:</h5>
2932
2933<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2934The first argument is the value to write to the memory mapped I/O location.
2935The second argument is a pointer indicating the memory address to which the
2936data should be written.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2937</p>
2938
2939<h5>Semantics:</h5>
2940
2941<p>
2942The '<tt>llvm.writeio</tt>' intrinsic writes <i>value</i> to the memory mapped
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2943I/O address specified by <i>pointer</i>. The value must be a
2944<a href="#t_firstclass">first class</a> type. However, certain architectures
Misha Brukmancfa87bc2005-04-22 18:02:52 +0000[diff] [blame]2945may not support I/O on all first class types. For example, 32-bit processors
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2946may only support I/O on data types that are 32 bits or less.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2947</p>
2948
2949<p>
John Criswell96db6fc2004-04-12 16:33:19 +0000[diff] [blame]2950This intrinsic enforces an in-order memory model for llvm.readio and
2951llvm.writeio calls on machines that use dynamic scheduling. Dynamically
2952scheduled processors may execute loads and stores out of order, re-ordering at
2953run time accesses to memory mapped I/O registers. Using these intrinsics
2954ensures that accesses to memory mapped I/O registers occur in program order.
John Criswell183402a2004-04-12 15:02:16 +0000[diff] [blame]2955</p>
2956
2957</div>
2958
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2959<!-- ======================================================================= -->
2960<div class="doc_subsection">
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2961 <a name="int_libc">Standard C Library Intrinsics</a>
2962</div>
2963
2964<div class="doc_text">
2965<p>
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]2966LLVM provides intrinsics for a few important standard C library functions.
2967These intrinsics allow source-language front-ends to pass information about the
2968alignment of the pointer arguments to the code generator, providing opportunity
2969for more efficient code generation.
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2970</p>
2971
2972</div>
2973
2974<!-- _______________________________________________________________________ -->
2975<div class="doc_subsubsection">
2976 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
2977</div>
2978
2979<div class="doc_text">
2980
2981<h5>Syntax:</h5>
2982<pre>
Reid Spencerd4622352005-04-26 20:41:16 +0000[diff] [blame]2983 declare void %llvm.memcpy(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
2984 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]2985</pre>
2986
2987<h5>Overview:</h5>
2988
2989<p>
2990The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
2991location to the destination location.
2992</p>
2993
2994<p>
2995Note that, unlike the standard libc function, the <tt>llvm.memcpy</tt> intrinsic
2996does not return a value, and takes an extra alignment argument.
2997</p>
2998
2999<h5>Arguments:</h5>
3000
3001<p>
3002The first argument is a pointer to the destination, the second is a pointer to
3003the source. The third argument is an (arbitrarily sized) integer argument
3004specifying the number of bytes to copy, and the fourth argument is the alignment
3005of the source and destination locations.
3006</p>
3007
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3008<p>
3009If the call to this intrinisic has an alignment value that is not 0 or 1, then
3010the caller guarantees that the size of the copy is a multiple of the alignment
3011and that both the source and destination pointers are aligned to that boundary.
3012</p>
3013
Chris Lattner33aec9e2004-02-12 17:01:32 +0000[diff] [blame]3014<h5>Semantics:</h5>
3015
3016<p>
3017The '<tt>llvm.memcpy</tt>' intrinsic copies a block of memory from the source
3018location to the destination location, which are not allowed to overlap. It
3019copies "len" bytes of memory over. If the argument is known to be aligned to
3020some boundary, this can be specified as the fourth argument, otherwise it should
3021be set to 0 or 1.
3022</p>
3023</div>
3024
3025
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3026<!-- _______________________________________________________________________ -->
3027<div class="doc_subsubsection">
3028 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
3029</div>
3030
3031<div class="doc_text">
3032
3033<h5>Syntax:</h5>
3034<pre>
Reid Spencerd4622352005-04-26 20:41:16 +0000[diff] [blame]3035 declare void %llvm.memmove(sbyte* &lt;dest&gt;, sbyte* &lt;src&gt;,
3036 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3037</pre>
3038
3039<h5>Overview:</h5>
3040
3041<p>
3042The '<tt>llvm.memmove</tt>' intrinsic moves a block of memory from the source
3043location to the destination location. It is similar to the '<tt>llvm.memcpy</tt>'
3044intrinsic but allows the two memory locations to overlap.
3045</p>
3046
3047<p>
3048Note that, unlike the standard libc function, the <tt>llvm.memmove</tt> intrinsic
3049does not return a value, and takes an extra alignment argument.
3050</p>
3051
3052<h5>Arguments:</h5>
3053
3054<p>
3055The first argument is a pointer to the destination, the second is a pointer to
3056the source. The third argument is an (arbitrarily sized) integer argument
3057specifying the number of bytes to copy, and the fourth argument is the alignment
3058of the source and destination locations.
3059</p>
3060
Chris Lattner3301ced2004-02-12 21:18:15 +0000[diff] [blame]3061<p>
3062If the call to this intrinisic has an alignment value that is not 0 or 1, then
3063the caller guarantees that the size of the copy is a multiple of the alignment
3064and that both the source and destination pointers are aligned to that boundary.
3065</p>
3066
Chris Lattner0eb51b42004-02-12 18:10:10 +0000[diff] [blame]3067<h5>Semantics:</h5>
3068
3069<p>
3070The '<tt>llvm.memmove</tt>' intrinsic copies a block of memory from the source
3071location to the destination location, which may overlap. It
3072copies "len" bytes of memory over. If the argument is known to be aligned to
3073some boundary, this can be specified as the fourth argument, otherwise it should
3074be set to 0 or 1.
3075</p>
3076</div>
3077
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3078
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3079<!-- _______________________________________________________________________ -->
3080<div class="doc_subsubsection">
3081 <a name="i_memset">'<tt>llvm.memset</tt>' Intrinsic</a>
3082</div>
3083
3084<div class="doc_text">
3085
3086<h5>Syntax:</h5>
3087<pre>
Reid Spencerd4622352005-04-26 20:41:16 +0000[diff] [blame]3088 declare void %llvm.memset(sbyte* &lt;dest&gt;, ubyte &lt;val&gt;,
3089 uint &lt;len&gt;, uint &lt;align&gt;)
Chris Lattner10610642004-02-14 04:08:35 +0000[diff] [blame]3090</pre>
3091
3092<h5>Overview:</h5>
3093
3094<p>
3095The '<tt>llvm.memset</tt>' intrinsic fills a block of memory with a particular
3096byte value.
3097</p>
3098
3099<p>
3100Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
3101does not return a value, and takes an extra alignment argument.
3102</p>
3103
3104<h5>Arguments:</h5>
3105
3106<p>
3107The first argument is a pointer to the destination to fill, the second is the
3108byte value to fill it with, the third argument is an (arbitrarily sized) integer
3109argument specifying the number of bytes to fill, and the fourth argument is the
3110known alignment of destination location.
3111</p>
3112
3113<p>
3114If the call to this intrinisic has an alignment value that is not 0 or 1, then
3115the caller guarantees that the size of the copy is a multiple of the alignment
3116and that the destination pointer is aligned to that boundary.
3117</p>
3118
3119<h5>Semantics:</h5>
3120
3121<p>
3122The '<tt>llvm.memset</tt>' intrinsic fills "len" bytes of memory starting at the
3123destination location. If the argument is known to be aligned to some boundary,
3124this can be specified as the fourth argument, otherwise it should be set to 0 or
31251.
3126</p>
3127</div>
3128
3129
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3130<!-- _______________________________________________________________________ -->
3131<div class="doc_subsubsection">
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3132 <a name="i_isunordered">'<tt>llvm.isunordered</tt>' Intrinsic</a>
3133</div>
3134
3135<div class="doc_text">
3136
3137<h5>Syntax:</h5>
3138<pre>
Reid Spencera8d451e2005-04-26 20:50:44 +0000[diff] [blame]3139 declare bool %llvm.isunordered(&lt;float or double&gt; Val1, &lt;float or double&gt; Val2)
Alkis Evlogimenos26bbe932004-06-13 01:16:15 +0000[diff] [blame]3140</pre>
3141
3142<h5>Overview:</h5>
3143
3144<p>
3145The '<tt>llvm.isunordered</tt>' intrinsic returns true if either or both of the
3146specified floating point values is a NAN.
3147</p>
3148
3149<h5>Arguments:</h5>
3150
3151<p>
3152The arguments are floating point numbers of the same type.
3153</p>
3154
3155<h5>Semantics:</h5>
3156
3157<p>
3158If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
3159false.
3160</p>
3161</div>
3162
3163
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3164<!-- ======================================================================= -->
3165<div class="doc_subsection">
3166 <a name="int_count">Bit Counting Intrinsics</a>
3167</div>
3168
3169<div class="doc_text">
3170<p>
3171LLVM provides intrinsics for a few important bit counting operations.
3172These allow efficient code generation for some algorithms.
3173</p>
3174
3175</div>
3176
3177<!-- _______________________________________________________________________ -->
3178<div class="doc_subsubsection">
3179 <a name="int_ctpop">'<tt>llvm.ctpop</tt>' Intrinsic</a>
3180</div>
3181
3182<div class="doc_text">
3183
3184<h5>Syntax:</h5>
3185<pre>
3186 declare int %llvm.ctpop(int &lt;src&gt;)
3187
3188</pre>
3189
3190<h5>Overview:</h5>
3191
3192<p>
3193The '<tt>llvm.ctpop</tt>' intrinsic counts the number of ones in a variable.
3194</p>
3195
3196<h5>Arguments:</h5>
3197
3198<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]3199The only argument is the value to be counted. The argument may be of any
3200integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3201</p>
3202
3203<h5>Semantics:</h5>
3204
3205<p>
3206The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
3207</p>
3208</div>
3209
3210<!-- _______________________________________________________________________ -->
3211<div class="doc_subsubsection">
3212 <a name="int_cttz">'<tt>llvm.cttz</tt>' Intrinsic</a>
3213</div>
3214
3215<div class="doc_text">
3216
3217<h5>Syntax:</h5>
3218<pre>
3219 declare int %llvm.cttz(int &lt;src&gt;)
3220
3221</pre>
3222
3223<h5>Overview:</h5>
3224
3225<p>
3226The '<tt>llvm.cttz</tt>' intrinsic counts the number of trailing zeros.
3227</p>
3228
3229<h5>Arguments:</h5>
3230
3231<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]3232The only argument is the value to be counted. The argument may be of any
3233integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3234</p>
3235
3236<h5>Semantics:</h5>
3237
3238<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]3239The '<tt>llvm.cttz</tt>' intrinsic counts the trailing zeros in a variable. If
3240the src == 0 then the result is the size in bits of the type of src.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3241</p>
3242</div>
3243
3244<!-- _______________________________________________________________________ -->
3245<div class="doc_subsubsection">
3246 <a name="int_ctlz">'<tt>llvm.ctlz</tt>' Intrinsic</a>
3247</div>
3248
3249<div class="doc_text">
3250
3251<h5>Syntax:</h5>
3252<pre>
3253 declare int %llvm.ctlz(int &lt;src&gt;)
3254
3255</pre>
3256
3257<h5>Overview:</h5>
3258
3259<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]3260The '<tt>llvm.ctlz</tt>' intrinsic counts the number of leading zeros in a
3261variable.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3262</p>
3263
3264<h5>Arguments:</h5>
3265
3266<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]3267The only argument is the value to be counted. The argument may be of any
3268integer type. The return type must match the argument type.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3269</p>
3270
3271<h5>Semantics:</h5>
3272
3273<p>
Chris Lattnercfe6b372005-05-07 01:46:40 +0000[diff] [blame^]3274The '<tt>llvm.ctlz</tt>' intrinsic counts the leading zeros in a variable. If
3275the src == 0 then the result is the size in bits of the type of src.
Andrew Lenharthec370fd2005-05-03 18:01:48 +0000[diff] [blame]3276</p>
3277</div>
Chris Lattner32006282004-06-11 02:28:03 +0000[diff] [blame]3278
3279
Chris Lattner8ff75902004-01-06 05:31:32 +0000[diff] [blame]3280<!-- ======================================================================= -->
3281<div class="doc_subsection">
3282 <a name="int_debugger">Debugger Intrinsics</a>
3283</div>
3284
3285<div class="doc_text">
3286<p>
3287The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
3288are described in the <a
3289href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
3290Debugging</a> document.
3291</p>
3292</div>
3293
3294
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3295<!-- *********************************************************************** -->
Chris Lattner00950542001-06-06 20:29:01 +0000[diff] [blame]3296<hr>
Misha Brukmandaa4cb02004-03-01 17:47:27 +0000[diff] [blame]3297<address>
3298 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
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3301 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
3302
3303 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
3304 <a href="http://llvm.cs.uiuc.edu">The LLVM Compiler Infrastructure</a><br>
3305 Last modified: $Date$
3306</address>
Misha Brukman9d0919f2003-11-08 01:05:38 +0000[diff] [blame]3307</body>
3308</html>