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gerrit-public.fairphone.software / toolchain / llvm-project / 72ba4990048ba8cf8b72a94f374502f5dda43b03 / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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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 Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 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 Lattner6af02f32004-12-09 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 Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]27 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]28 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]29 </ol>
30 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]31 <li><a href="#typesystem">Type System</a>
32 <ol>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]33 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]34 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]35 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]36 </ol>
37 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]38 <li><a href="#t_derived">Derived Types</a>
39 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]40 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]41 <li><a href="#t_function">Function Type</a></li>
42 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]43 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]44 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]45 <li><a href="#t_packed">Packed Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]46 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]47 </ol>
48 </li>
49 </ol>
50 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]51 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]52 <ol>
53 <li><a href="#simpleconstants">Simple Constants</a>
54 <li><a href="#aggregateconstants">Aggregate Constants</a>
55 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
56 <li><a href="#undefvalues">Undefined Values</a>
57 <li><a href="#constantexprs">Constant Expressions</a>
58 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]59 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]60 <li><a href="#othervalues">Other Values</a>
61 <ol>
62 <li><a href="#inlineasm">Inline Assembler Expressions</a>
63 </ol>
64 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]65 <li><a href="#instref">Instruction Reference</a>
66 <ol>
67 <li><a href="#terminators">Terminator Instructions</a>
68 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]69 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
70 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]71 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
72 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]73 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]74 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 </ol>
76 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]77 <li><a href="#binaryops">Binary Operations</a>
78 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]79 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
80 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
81 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]82 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
83 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
84 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]85 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
86 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
87 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]88 </ol>
89 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]90 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
91 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]92 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]93 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]94 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
95 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]96 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
97 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 </ol>
99 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]100 <li><a href="#vectorops">Vector Operations</a>
101 <ol>
102 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
103 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
104 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]105 </ol>
106 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]107 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]108 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]109 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
110 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
111 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]112 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
113 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
114 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]115 </ol>
116 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]117 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]118 <ol>
119 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
120 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
121 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
122 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
123 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]124 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
126 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
127 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]128 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
129 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]130 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]131 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]132 <li><a href="#otherops">Other Operations</a>
133 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]134 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
135 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]136 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]137 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]139 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]140 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]141 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]142 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]144 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]145 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]146 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
147 <ol>
148 <li><a href="#i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
149 <li><a href="#i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
150 <li><a href="#i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
151 </ol>
152 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]153 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
154 <ol>
155 <li><a href="#i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
156 <li><a href="#i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
157 <li><a href="#i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
158 </ol>
159 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]160 <li><a href="#int_codegen">Code Generator Intrinsics</a>
161 <ol>
162 <li><a href="#i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
163 <li><a href="#i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]164 <li><a href="#i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
165 <li><a href="#i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]166 <li><a href="#i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]167 <li><a href="#i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]168 <li><a href="#i_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]169 </ol>
170 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]171 <li><a href="#int_libc">Standard C Library Intrinsics</a>
172 <ol>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]173 <li><a href="#i_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
174 <li><a href="#i_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
175 <li><a href="#i_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]176 <li><a href="#i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a></li>
177 <li><a href="#i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]178 <li><a href="#i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]179 </ol>
180 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]181 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]182 <ol>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]183 <li><a href="#i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]184 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
185 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]187 </ol>
188 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]189 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]192</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]193
194<div class="doc_author">
195 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
196 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]197</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]198
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]199<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]200<div class="doc_section"> <a name="abstract">Abstract </a></div>
201<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]202
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]203<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]204<p>This document is a reference manual for the LLVM assembly language.
205LLVM is an SSA based representation that provides type safety,
206low-level operations, flexibility, and the capability of representing
207'all' high-level languages cleanly. It is the common code
208representation used throughout all phases of the LLVM compilation
209strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]210</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]211
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]212<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]213<div class="doc_section"> <a name="introduction">Introduction</a> </div>
214<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]215
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]216<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]217
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]218<p>The LLVM code representation is designed to be used in three
219different forms: as an in-memory compiler IR, as an on-disk bytecode
220representation (suitable for fast loading by a Just-In-Time compiler),
221and as a human readable assembly language representation. This allows
222LLVM to provide a powerful intermediate representation for efficient
223compiler transformations and analysis, while providing a natural means
224to debug and visualize the transformations. The three different forms
225of LLVM are all equivalent. This document describes the human readable
226representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]227
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]228<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]229while being expressive, typed, and extensible at the same time. It
230aims to be a "universal IR" of sorts, by being at a low enough level
231that high-level ideas may be cleanly mapped to it (similar to how
232microprocessors are "universal IR's", allowing many source languages to
233be mapped to them). By providing type information, LLVM can be used as
234the target of optimizations: for example, through pointer analysis, it
235can be proven that a C automatic variable is never accessed outside of
236the current function... allowing it to be promoted to a simple SSA
237value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]238
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]239</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]240
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]241<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]242<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]243
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]244<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]245
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]246<p>It is important to note that this document describes 'well formed'
247LLVM assembly language. There is a difference between what the parser
248accepts and what is considered 'well formed'. For example, the
249following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]250
251<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]252 %x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]253</pre>
254
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]255<p>...because the definition of <tt>%x</tt> does not dominate all of
256its uses. The LLVM infrastructure provides a verification pass that may
257be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]258automatically run by the parser after parsing input assembly and by
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]259the optimizer before it outputs bytecode. The violations pointed out
260by the verifier pass indicate bugs in transformation passes or input to
261the parser.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]262
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]263<!-- Describe the typesetting conventions here. --> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]264
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]265<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]266<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]267<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]268
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]269<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]270
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]271<p>LLVM uses three different forms of identifiers, for different
272purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]273
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]274<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]275 <li>Named values are represented as a string of characters with a '%' prefix.
276 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
277 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
278 Identifiers which require other characters in their names can be surrounded
279 with quotes. In this way, anything except a <tt>"</tt> character can be used
280 in a name.</li>
281
282 <li>Unnamed values are represented as an unsigned numeric value with a '%'
283 prefix. For example, %12, %2, %44.</li>
284
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]285 <li>Constants, which are described in a <a href="#constants">section about
286 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]287</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]288
289<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
290don't need to worry about name clashes with reserved words, and the set of
291reserved words may be expanded in the future without penalty. Additionally,
292unnamed identifiers allow a compiler to quickly come up with a temporary
293variable without having to avoid symbol table conflicts.</p>
294
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]295<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]296languages. There are keywords for different opcodes
297('<tt><a href="#i_add">add</a></tt>',
298 '<tt><a href="#i_bitcast">bitcast</a></tt>',
299 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]300href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]301and others. These reserved words cannot conflict with variable names, because
302none of them start with a '%' character.</p>
303
304<p>Here is an example of LLVM code to multiply the integer variable
305'<tt>%X</tt>' by 8:</p>
306
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]307<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]308
309<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]310 %result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]311</pre>
312
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]313<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]314
315<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]316 %result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]317</pre>
318
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]319<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]320
321<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]322 <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
323 <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
324 %result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]325</pre>
326
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]327<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
328important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]330<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]331
332 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
333 line.</li>
334
335 <li>Unnamed temporaries are created when the result of a computation is not
336 assigned to a named value.</li>
337
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]338 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]339
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]340</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]341
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]342<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]343demonstrating instructions, we will follow an instruction with a comment that
344defines the type and name of value produced. Comments are shown in italic
345text.</p>
346
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]347</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]348
349<!-- *********************************************************************** -->
350<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
351<!-- *********************************************************************** -->
352
353<!-- ======================================================================= -->
354<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
355</div>
356
357<div class="doc_text">
358
359<p>LLVM programs are composed of "Module"s, each of which is a
360translation unit of the input programs. Each module consists of
361functions, global variables, and symbol table entries. Modules may be
362combined together with the LLVM linker, which merges function (and
363global variable) definitions, resolves forward declarations, and merges
364symbol table entries. Here is an example of the "hello world" module:</p>
365
366<pre><i>; Declare the string constant as a global constant...</i>
367<a href="#identifiers">%.LC0</a> = <a href="#linkage_internal">internal</a> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]368 href="#globalvars">constant</a> <a href="#t_array">[13 x i8 ]</a> c"hello world\0A\00" <i>; [13 x i8 ]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]369
370<i>; External declaration of the puts function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]371<a href="#functionstructure">declare</a> i32 %puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]372
Chris Lattnerd2d29a02006-06-13 03:05:47 +0000[diff] [blame]373<i>; Global variable / Function body section separator</i>
374implementation
375
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]376<i>; Definition of main function</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]377define i32 %main() { <i>; i32()* </i>
378 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]379 %cast210 = <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]380 href="#i_getelementptr">getelementptr</a> [13 x i8 ]* %.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]381
382 <i>; Call puts function to write out the string to stdout...</i>
383 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]384 href="#i_call">call</a> i32 %puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]385 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]386 href="#i_ret">ret</a> i32 0<br>}<br></pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]387
388<p>This example is made up of a <a href="#globalvars">global variable</a>
389named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
390function, and a <a href="#functionstructure">function definition</a>
391for "<tt>main</tt>".</p>
392
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]393<p>In general, a module is made up of a list of global values,
394where both functions and global variables are global values. Global values are
395represented by a pointer to a memory location (in this case, a pointer to an
396array of char, and a pointer to a function), and have one of the following <a
397href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]398
Chris Lattnerd2d29a02006-06-13 03:05:47 +0000[diff] [blame]399<p>Due to a limitation in the current LLVM assembly parser (it is limited by
400one-token lookahead), modules are split into two pieces by the "implementation"
401keyword. Global variable prototypes and definitions must occur before the
402keyword, and function definitions must occur after it. Function prototypes may
403occur either before or after it. In the future, the implementation keyword may
404become a noop, if the parser gets smarter.</p>
405
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]406</div>
407
408<!-- ======================================================================= -->
409<div class="doc_subsection">
410 <a name="linkage">Linkage Types</a>
411</div>
412
413<div class="doc_text">
414
415<p>
416All Global Variables and Functions have one of the following types of linkage:
417</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]418
419<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]420
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]421 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]422
423 <dd>Global values with internal linkage are only directly accessible by
424 objects in the current module. In particular, linking code into a module with
425 an internal global value may cause the internal to be renamed as necessary to
426 avoid collisions. Because the symbol is internal to the module, all
427 references can be updated. This corresponds to the notion of the
428 '<tt>static</tt>' keyword in C, or the idea of "anonymous namespaces" in C++.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]429 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]430
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]431 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]432
433 <dd>"<tt>linkonce</tt>" linkage is similar to <tt>internal</tt> linkage, with
434 the twist that linking together two modules defining the same
435 <tt>linkonce</tt> globals will cause one of the globals to be discarded. This
436 is typically used to implement inline functions. Unreferenced
437 <tt>linkonce</tt> globals are allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]438 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]439
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]440 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]441
442 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
443 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]444 used to implement constructs in C such as "<tt>i32 X;</tt>" at global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]445 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]446
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]447 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
449 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
450 pointer to array type. When two global variables with appending linkage are
451 linked together, the two global arrays are appended together. This is the
452 LLVM, typesafe, equivalent of having the system linker append together
453 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]454 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]455
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]456 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457
458 <dd>If none of the above identifiers are used, the global is externally
459 visible, meaning that it participates in linkage and can be used to resolve
460 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]461 </dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]462
463 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
464
465 <dd>"<tt>extern_weak</tt>" TBD
466 </dd>
467
468 <p>
469 The next two types of linkage are targeted for Microsoft Windows platform
470 only. They are designed to support importing (exporting) symbols from (to)
471 DLLs.
472 </p>
473
474 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
475
476 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
477 or variable via a global pointer to a pointer that is set up by the DLL
478 exporting the symbol. On Microsoft Windows targets, the pointer name is
479 formed by combining <code>_imp__</code> and the function or variable name.
480 </dd>
481
482 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
483
484 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
485 pointer to a pointer in a DLL, so that it can be referenced with the
486 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
487 name is formed by combining <code>_imp__</code> and the function or variable
488 name.
489 </dd>
490
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]491</dl>
492
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]493<p><a name="linkage_external">For example, since the "<tt>.LC0</tt>"
494variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
495variable and was linked with this one, one of the two would be renamed,
496preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
497external (i.e., lacking any linkage declarations), they are accessible
498outside of the current module. It is illegal for a function <i>declaration</i>
499to have any linkage type other than "externally visible".</a></p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]500
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]501</div>
502
503<!-- ======================================================================= -->
504<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]505 <a name="callingconv">Calling Conventions</a>
506</div>
507
508<div class="doc_text">
509
510<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
511and <a href="#i_invoke">invokes</a> can all have an optional calling convention
512specified for the call. The calling convention of any pair of dynamic
513caller/callee must match, or the behavior of the program is undefined. The
514following calling conventions are supported by LLVM, and more may be added in
515the future:</p>
516
517<dl>
518 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
519
520 <dd>This calling convention (the default if no other calling convention is
521 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]522 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame^]523 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]524 </dd>
525
Chris Lattner95ff1952006-05-19 21:15:36 +0000[diff] [blame]526 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
527
528 <dd>This calling convention matches the target C calling conventions, except
529 that functions with this convention are required to take a pointer as their
530 first argument, and the return type of the function must be void. This is
531 used for C functions that return aggregates by-value. In this case, the
532 function has been transformed to take a pointer to the struct as the first
533 argument to the function. For targets where the ABI specifies specific
534 behavior for structure-return calls, the calling convention can be used to
535 distinguish between struct return functions and other functions that take a
536 pointer to a struct as the first argument.
537 </dd>
538
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]539 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
540
541 <dd>This calling convention attempts to make calls as fast as possible
542 (e.g. by passing things in registers). This calling convention allows the
543 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]544 without having to conform to an externally specified ABI. Implementations of
545 this convention should allow arbitrary tail call optimization to be supported.
546 This calling convention does not support varargs and requires the prototype of
547 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]548 </dd>
549
550 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
551
552 <dd>This calling convention attempts to make code in the caller as efficient
553 as possible under the assumption that the call is not commonly executed. As
554 such, these calls often preserve all registers so that the call does not break
555 any live ranges in the caller side. This calling convention does not support
556 varargs and requires the prototype of all callees to exactly match the
557 prototype of the function definition.
558 </dd>
559
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]560 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]561
562 <dd>Any calling convention may be specified by number, allowing
563 target-specific calling conventions to be used. Target specific calling
564 conventions start at 64.
565 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]566</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]567
568<p>More calling conventions can be added/defined on an as-needed basis, to
569support pascal conventions or any other well-known target-independent
570convention.</p>
571
572</div>
573
574<!-- ======================================================================= -->
575<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]576 <a name="globalvars">Global Variables</a>
577</div>
578
579<div class="doc_text">
580
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]581<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]582instead of run-time. Global variables may optionally be initialized, may have
583an explicit section to be placed in, and may
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]584have an optional explicit alignment specified. A
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]585variable may be defined as a global "constant," which indicates that the
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]586contents of the variable will <b>never</b> be modified (enabling better
587optimization, allowing the global data to be placed in the read-only section of
588an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]589cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]590
591<p>
592LLVM explicitly allows <em>declarations</em> of global variables to be marked
593constant, even if the final definition of the global is not. This capability
594can be used to enable slightly better optimization of the program, but requires
595the language definition to guarantee that optimizations based on the
596'constantness' are valid for the translation units that do not include the
597definition.
598</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]599
600<p>As SSA values, global variables define pointer values that are in
601scope (i.e. they dominate) all basic blocks in the program. Global
602variables always define a pointer to their "content" type because they
603describe a region of memory, and all memory objects in LLVM are
604accessed through pointers.</p>
605
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]606<p>LLVM allows an explicit section to be specified for globals. If the target
607supports it, it will emit globals to the section specified.</p>
608
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]609<p>An explicit alignment may be specified for a global. If not present, or if
610the alignment is set to zero, the alignment of the global is set by the target
611to whatever it feels convenient. If an explicit alignment is specified, the
612global is forced to have at least that much alignment. All alignments must be
613a power of 2.</p>
614
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]615</div>
616
617
618<!-- ======================================================================= -->
619<div class="doc_subsection">
620 <a name="functionstructure">Functions</a>
621</div>
622
623<div class="doc_text">
624
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]625<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
626an optional <a href="#linkage">linkage type</a>, an optional
627<a href="#callingconv">calling convention</a>, a return type, an optional
628<a href="#paramattrs">parameter attribute</a> for the return type, a function
629name, a (possibly empty) argument list (each with optional
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]630<a href="#paramattrs">parameter attributes</a>), an optional section, an
631optional alignment, an opening curly brace, a list of basic blocks, and a
632closing curly brace. LLVM function declarations
633consist of the "<tt>declare</tt>" keyword, an optional <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]634 href="#callingconv">calling convention</a>, a return type, an optional
635<a href="#paramattrs">parameter attribute</a> for the return type, a function
636name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]637
638<p>A function definition contains a list of basic blocks, forming the CFG for
639the function. Each basic block may optionally start with a label (giving the
640basic block a symbol table entry), contains a list of instructions, and ends
641with a <a href="#terminators">terminator</a> instruction (such as a branch or
642function return).</p>
643
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]644<p>The first basic block in a program is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]645executed on entrance to the function, and it is not allowed to have predecessor
646basic blocks (i.e. there can not be any branches to the entry block of a
647function). Because the block can have no predecessors, it also cannot have any
648<a href="#i_phi">PHI nodes</a>.</p>
649
650<p>LLVM functions are identified by their name and type signature. Hence, two
651functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]652considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]653appropriately.</p>
654
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]655<p>LLVM allows an explicit section to be specified for functions. If the target
656supports it, it will emit functions to the section specified.</p>
657
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]658<p>An explicit alignment may be specified for a function. If not present, or if
659the alignment is set to zero, the alignment of the function is set by the target
660to whatever it feels convenient. If an explicit alignment is specified, the
661function is forced to have at least that much alignment. All alignments must be
662a power of 2.</p>
663
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]664</div>
665
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]666<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]667<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
668<div class="doc_text">
669 <p>The return type and each parameter of a function type may have a set of
670 <i>parameter attributes</i> associated with them. Parameter attributes are
671 used to communicate additional information about the result or parameters of
672 a function. Parameter attributes are considered to be part of the function
673 type so two functions types that differ only by the parameter attributes
674 are different function types.</p>
675
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]676 <p>Parameter attributes consist of an at sign (@) followed by either a single
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]677 keyword or a comma separate list of keywords enclosed in parentheses. For
678 example:<pre>
679 %someFunc = i16 @zext (i8 @(sext) %someParam)
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]680 %someFunc = i16 @zext (i8 @zext %someParam)</pre>
681 Note that the two function types above are unique because the parameter
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]682 has a different attribute (@sext in the first one, @zext in the second).</p>
683
684 <p>Currently, only the following parameter attributes are defined:
685 <dl>
686 <dt><tt>@zext</tt></dt>
687 <dd>This indicates that the parameter should be zero extended just before
688 a call to this function.</dd>
689 <dt><tt>@sext</tt></dt>
690 <dd>This indicates that the parameter should be sign extended just before
691 a call to this function.</dd>
692 </dl></p>
693
694 <p>The current motivation for parameter attributes is to enable the sign and
695 zero extend information necessary for the C calling convention to be passed
696 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
697 are used by the code generator to perform the required extension. However,
698 parameter attributes are an orthogonal feature to calling conventions and
699 may be used for other purposes in the future.</p>
700</div>
701
702<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]703<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]704 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]705</div>
706
707<div class="doc_text">
708<p>
709Modules may contain "module-level inline asm" blocks, which corresponds to the
710GCC "file scope inline asm" blocks. These blocks are internally concatenated by
711LLVM and treated as a single unit, but may be separated in the .ll file if
712desired. The syntax is very simple:
713</p>
714
715<div class="doc_code"><pre>
Chris Lattnera1280ad2006-01-24 00:37:20 +0000[diff] [blame]716 module asm "inline asm code goes here"
717 module asm "more can go here"
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]718</pre></div>
719
720<p>The strings can contain any character by escaping non-printable characters.
721 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
722 for the number.
723</p>
724
725<p>
726 The inline asm code is simply printed to the machine code .s file when
727 assembly code is generated.
728</p>
729</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]730
731
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]732<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]733<div class="doc_section"> <a name="typesystem">Type System</a> </div>
734<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]735
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]736<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]737
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]738<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]739intermediate representation. Being typed enables a number of
740optimizations to be performed on the IR directly, without having to do
741extra analyses on the side before the transformation. A strong type
742system makes it easier to read the generated code and enables novel
743analyses and transformations that are not feasible to perform on normal
744three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]745
746</div>
747
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]748<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]749<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]750<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]751<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]752system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]753
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]754<table class="layout">
755 <tr class="layout">
756 <td class="left">
757 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]758 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]759 <tr><th>Type</th><th>Description</th></tr>
760 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]761 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
762 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]763 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]764 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]765 </tbody>
766 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]767 </td>
768 <td class="right">
769 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]770 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]771 <tr><th>Type</th><th>Description</th></tr>
772 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]773 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
774 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
775 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]776 </tbody>
777 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]778 </td>
779 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]780</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]781</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]782
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]783<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]784<div class="doc_subsubsection"> <a name="t_classifications">Type
785Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]786<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]787<p>These different primitive types fall into a few useful
788classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]789
790<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]791 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]792 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]793 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]794 <td><a name="t_integer">integer</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]795 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]796 </tr>
797 <tr>
798 <td><a name="t_integral">integral</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]799 <td><tt>bool, i8, i16, i32, i64</tt>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]800 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]801 </tr>
802 <tr>
803 <td><a name="t_floating">floating point</a></td>
804 <td><tt>float, double</tt></td>
805 </tr>
806 <tr>
807 <td><a name="t_firstclass">first class</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]808 <td><tt>bool, i8, i16, i32, i64, float, double, <br/>
809 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
810 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]811 </tr>
812 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]813</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]814
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]815<p>The <a href="#t_firstclass">first class</a> types are perhaps the
816most important. Values of these types are the only ones which can be
817produced by instructions, passed as arguments, or used as operands to
818instructions. This means that all structures and arrays must be
819manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]820</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]821
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]822<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]823<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]824
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]825<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]826
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]827<p>The real power in LLVM comes from the derived types in the system.
828This is what allows a programmer to represent arrays, functions,
829pointers, and other useful types. Note that these derived types may be
830recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]831
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]832</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]833
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]834<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]835<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]836
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]837<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]838
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]839<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]840
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]841<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]842sequentially in memory. The array type requires a size (number of
843elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]844
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]845<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]846
847<pre>
848 [&lt;# elements&gt; x &lt;elementtype&gt;]
849</pre>
850
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]851<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]852be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]853
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]854<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]855<table class="layout">
856 <tr class="layout">
857 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]858 <tt>[40 x i32 ]</tt><br/>
859 <tt>[41 x i32 ]</tt><br/>
860 <tt>[40 x i32]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]861 </td>
862 <td class="left">
863 Array of 40 integer values.<br/>
864 Array of 41 integer values.<br/>
865 Array of 40 unsigned integer values.<br/>
866 </td>
867 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]868</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]869<p>Here are some examples of multidimensional arrays:</p>
870<table class="layout">
871 <tr class="layout">
872 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]873 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]874 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]875 <tt>[2 x [3 x [4 x i32]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]876 </td>
877 <td class="left">
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]878 3x4 array of integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]879 12x10 array of single precision floating point values.<br/>
880 2x3x4 array of unsigned integer values.<br/>
881 </td>
882 </tr>
883</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]884
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]885<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
886length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]887LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
888As a special case, however, zero length arrays are recognized to be variable
889length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]890type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]891
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]892</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]893
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]894<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]895<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]896<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]897<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]898<p>The function type can be thought of as a function signature. It
899consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]900Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]901(which are structures of pointers to functions), for indirect function
902calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]903<p>
904The return type of a function type cannot be an aggregate type.
905</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]906<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]907<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]908<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]909specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]910which indicates that the function takes a variable number of arguments.
911Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]912 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]913<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]914<table class="layout">
915 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]916 <td class="left"><tt>i32 (i32)</tt></td>
917 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]918 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]919 </tr><tr class="layout">
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]920 <td class="left"><tt>float&nbsp;(i16&nbsp;@sext,&nbsp;i32&nbsp;*)&nbsp;*
921 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]922 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
923 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]924 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]925 <tt>float</tt>.
926 </td>
927 </tr><tr class="layout">
928 <td class="left"><tt>i32 (i8*, ...)</tt></td>
929 <td class="left">A vararg function that takes at least one
930 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (signed char in C),
931 which returns an integer. This is the signature for <tt>printf</tt> in
932 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]933 </td>
934 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]935</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]936
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]937</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]938<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]939<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]940<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]941<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]942<p>The structure type is used to represent a collection of data members
943together in memory. The packing of the field types is defined to match
944the ABI of the underlying processor. The elements of a structure may
945be any type that has a size.</p>
946<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
947and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
948field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
949instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]950<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]951<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]952<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]953<table class="layout">
954 <tr class="layout">
955 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]956 <tt>{ i32, i32, i32 }</tt><br/>
957 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]958 </td>
959 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]960 a triple of three <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]961 A pair, where the first element is a <tt>float</tt> and the second element
962 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]963 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]964 </td>
965 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]966</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]967</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]968
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]969<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]970<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
971</div>
972<div class="doc_text">
973<h5>Overview:</h5>
974<p>The packed structure type is used to represent a collection of data members
975together in memory. There is no padding between fields. Further, the alignment
976of a packed structure is 1 byte. The elements of a packed structure may
977be any type that has a size.</p>
978<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
979and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
980field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
981instruction.</p>
982<h5>Syntax:</h5>
983<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
984<h5>Examples:</h5>
985<table class="layout">
986 <tr class="layout">
987 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]988 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
989 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]990 </td>
991 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]992 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]993 A pair, where the first element is a <tt>float</tt> and the second element
994 is a <a href="#t_pointer">pointer</a> to a <a href="#t_function">function</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]995 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]996 </td>
997 </tr>
998</table>
999</div>
1000
1001<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1002<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1003<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1004<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1005<p>As in many languages, the pointer type represents a pointer or
1006reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1007<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1008<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1009<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1010<table class="layout">
1011 <tr class="layout">
1012 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1013 <tt>[4x i32]*</tt><br/>
1014 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1015 </td>
1016 <td class="left">
1017 A <a href="#t_pointer">pointer</a> to <a href="#t_array">array</a> of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1018 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1019 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1020 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1021 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1022 </td>
1023 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1024</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1025</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1026
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1027<!-- _______________________________________________________________________ -->
1028<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1029<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1030
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1031<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1032
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1033<p>A packed type is a simple derived type that represents a vector
1034of elements. Packed types are used when multiple primitive data
1035are operated in parallel using a single instruction (SIMD).
1036A packed type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1037elements) and an underlying primitive data type. Vectors must have a power
1038of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1039considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1040
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1041<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1042
1043<pre>
1044 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1045</pre>
1046
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1047<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1048be any integral or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1049
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1050<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1051
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1052<table class="layout">
1053 <tr class="layout">
1054 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1055 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1056 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1057 <tt>&lt;2 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1058 </td>
1059 <td class="left">
1060 Packed vector of 4 integer values.<br/>
1061 Packed vector of 8 floating-point values.<br/>
1062 Packed vector of 2 unsigned integer values.<br/>
1063 </td>
1064 </tr>
1065</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1066</div>
1067
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1068<!-- _______________________________________________________________________ -->
1069<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1070<div class="doc_text">
1071
1072<h5>Overview:</h5>
1073
1074<p>Opaque types are used to represent unknown types in the system. This
1075corresponds (for example) to the C notion of a foward declared structure type.
1076In LLVM, opaque types can eventually be resolved to any type (not just a
1077structure type).</p>
1078
1079<h5>Syntax:</h5>
1080
1081<pre>
1082 opaque
1083</pre>
1084
1085<h5>Examples:</h5>
1086
1087<table class="layout">
1088 <tr class="layout">
1089 <td class="left">
1090 <tt>opaque</tt>
1091 </td>
1092 <td class="left">
1093 An opaque type.<br/>
1094 </td>
1095 </tr>
1096</table>
1097</div>
1098
1099
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1100<!-- *********************************************************************** -->
1101<div class="doc_section"> <a name="constants">Constants</a> </div>
1102<!-- *********************************************************************** -->
1103
1104<div class="doc_text">
1105
1106<p>LLVM has several different basic types of constants. This section describes
1107them all and their syntax.</p>
1108
1109</div>
1110
1111<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1112<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1113
1114<div class="doc_text">
1115
1116<dl>
1117 <dt><b>Boolean constants</b></dt>
1118
1119 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1120 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1121 </dd>
1122
1123 <dt><b>Integer constants</b></dt>
1124
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1125 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1126 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1127 integer types.
1128 </dd>
1129
1130 <dt><b>Floating point constants</b></dt>
1131
1132 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1133 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1134 notation (see below). Floating point constants must have a <a
1135 href="#t_floating">floating point</a> type. </dd>
1136
1137 <dt><b>Null pointer constants</b></dt>
1138
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1139 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1140 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1141
1142</dl>
1143
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1144<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1145of floating point constants. For example, the form '<tt>double
11460x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11474.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1148(and the only time that they are generated by the disassembler) is when a
1149floating point constant must be emitted but it cannot be represented as a
1150decimal floating point number. For example, NaN's, infinities, and other
1151special values are represented in their IEEE hexadecimal format so that
1152assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1153
1154</div>
1155
1156<!-- ======================================================================= -->
1157<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1158</div>
1159
1160<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1161<p>Aggregate constants arise from aggregation of simple constants
1162and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1163
1164<dl>
1165 <dt><b>Structure constants</b></dt>
1166
1167 <dd>Structure constants are represented with notation similar to structure
1168 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1169 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1170 where "<tt>%G</tt>" is declared as "<tt>%G = external global i32</tt>". Structure constants
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1171 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1172 types of elements must match those specified by the type.
1173 </dd>
1174
1175 <dt><b>Array constants</b></dt>
1176
1177 <dd>Array constants are represented with notation similar to array type
1178 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1179 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1180 constants must have <a href="#t_array">array type</a>, and the number and
1181 types of elements must match those specified by the type.
1182 </dd>
1183
1184 <dt><b>Packed constants</b></dt>
1185
1186 <dd>Packed constants are represented with notation similar to packed type
1187 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1188 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1189 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1190 href="#t_packed">packed type</a>, and the number and types of elements must
1191 match those specified by the type.
1192 </dd>
1193
1194 <dt><b>Zero initialization</b></dt>
1195
1196 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1197 value to zero of <em>any</em> type, including scalar and aggregate types.
1198 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1199 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1200 initializers.
1201 </dd>
1202</dl>
1203
1204</div>
1205
1206<!-- ======================================================================= -->
1207<div class="doc_subsection">
1208 <a name="globalconstants">Global Variable and Function Addresses</a>
1209</div>
1210
1211<div class="doc_text">
1212
1213<p>The addresses of <a href="#globalvars">global variables</a> and <a
1214href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1215constants. These constants are explicitly referenced when the <a
1216href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1217href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1218file:</p>
1219
1220<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1221 %X = global i32 17
1222 %Y = global i32 42
1223 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1224</pre>
1225
1226</div>
1227
1228<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1229<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1230<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1231 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1232 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1233 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1234
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1235 <p>Undefined values indicate to the compiler that the program is well defined
1236 no matter what value is used, giving the compiler more freedom to optimize.
1237 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1238</div>
1239
1240<!-- ======================================================================= -->
1241<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1242</div>
1243
1244<div class="doc_text">
1245
1246<p>Constant expressions are used to allow expressions involving other constants
1247to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1248href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1249that does not have side effects (e.g. load and call are not supported). The
1250following is the syntax for constant expressions:</p>
1251
1252<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1253 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1254 <dd>Truncate a constant to another type. The bit size of CST must be larger
1255 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1256
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1257 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1258 <dd>Zero extend a constant to another type. The bit size of CST must be
1259 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1260
1261 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1262 <dd>Sign extend a constant to another type. The bit size of CST must be
1263 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1264
1265 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1266 <dd>Truncate a floating point constant to another floating point type. The
1267 size of CST must be larger than the size of TYPE. Both types must be
1268 floating point.</dd>
1269
1270 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1271 <dd>Floating point extend a constant to another type. The size of CST must be
1272 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1273
1274 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1275 <dd>Convert a floating point constant to the corresponding unsigned integer
1276 constant. TYPE must be an integer type. CST must be floating point. If the
1277 value won't fit in the integer type, the results are undefined.</dd>
1278
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1279 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1280 <dd>Convert a floating point constant to the corresponding signed integer
1281 constant. TYPE must be an integer type. CST must be floating point. If the
1282 value won't fit in the integer type, the results are undefined.</dd>
1283
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1284 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1285 <dd>Convert an unsigned integer constant to the corresponding floating point
1286 constant. TYPE must be floating point. CST must be of integer type. If the
1287 value won't fit in the floating point type, the results are undefined.</dd>
1288
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1289 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1290 <dd>Convert a signed integer constant to the corresponding floating point
1291 constant. TYPE must be floating point. CST must be of integer type. If the
1292 value won't fit in the floating point type, the results are undefined.</dd>
1293
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1294 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1295 <dd>Convert a pointer typed constant to the corresponding integer constant
1296 TYPE must be an integer type. CST must be of pointer type. The CST value is
1297 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1298
1299 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1300 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1301 pointer type. CST must be of integer type. The CST value is zero extended,
1302 truncated, or unchanged to make it fit in a pointer size. This one is
1303 <i>really</i> dangerous!</dd>
1304
1305 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1306 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1307 identical (same number of bits). The conversion is done as if the CST value
1308 was stored to memory and read back as TYPE. In other words, no bits change
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1309 with this operator, just the type. This can be used for conversion of
1310 packed types to any other type, as long as they have the same bit width. For
1311 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1312 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1313
1314 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1315
1316 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1317 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1318 instruction, the index list may have zero or more indexes, which are required
1319 to make sense for the type of "CSTPTR".</dd>
1320
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1321 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1322
1323 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1324 constants.</dd>
1325
1326 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1327 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1328
1329 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1330 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1331
1332 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1333
1334 <dd>Perform the <a href="#i_extractelement">extractelement
1335 operation</a> on constants.
1336
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1337 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1338
1339 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1340 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1341
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1342
1343 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1344
1345 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1346 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1347
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1348 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1349
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1350 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1351 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1352 binary</a> operations. The constraints on operands are the same as those for
1353 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1354 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1355</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1356</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1357
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1358<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1359<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1360<!-- *********************************************************************** -->
1361
1362<!-- ======================================================================= -->
1363<div class="doc_subsection">
1364<a name="inlineasm">Inline Assembler Expressions</a>
1365</div>
1366
1367<div class="doc_text">
1368
1369<p>
1370LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1371Module-Level Inline Assembly</a>) through the use of a special value. This
1372value represents the inline assembler as a string (containing the instructions
1373to emit), a list of operand constraints (stored as a string), and a flag that
1374indicates whether or not the inline asm expression has side effects. An example
1375inline assembler expression is:
1376</p>
1377
1378<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1379 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1380</pre>
1381
1382<p>
1383Inline assembler expressions may <b>only</b> be used as the callee operand of
1384a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1385</p>
1386
1387<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1388 %X = call i32 asm "<a href="#i_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1389</pre>
1390
1391<p>
1392Inline asms with side effects not visible in the constraint list must be marked
1393as having side effects. This is done through the use of the
1394'<tt>sideeffect</tt>' keyword, like so:
1395</p>
1396
1397<pre>
1398 call void asm sideeffect "eieio", ""()
1399</pre>
1400
1401<p>TODO: The format of the asm and constraints string still need to be
1402documented here. Constraints on what can be done (e.g. duplication, moving, etc
1403need to be documented).
1404</p>
1405
1406</div>
1407
1408<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1409<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1410<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1411
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1412<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1413
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1414<p>The LLVM instruction set consists of several different
1415classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1416instructions</a>, <a href="#binaryops">binary instructions</a>,
1417<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1418 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1419instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1420
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1421</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1422
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1423<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1424<div class="doc_subsection"> <a name="terminators">Terminator
1425Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1426
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1427<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1428
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1429<p>As mentioned <a href="#functionstructure">previously</a>, every
1430basic block in a program ends with a "Terminator" instruction, which
1431indicates which block should be executed after the current block is
1432finished. These terminator instructions typically yield a '<tt>void</tt>'
1433value: they produce control flow, not values (the one exception being
1434the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1435<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1436 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1437instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1438the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1439 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1440 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1441
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1442</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1443
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1444<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1445<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1446Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1447<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1448<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1449<pre> ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1450 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1451</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1452<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1453<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1454value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1455<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1456returns a value and then causes control flow, and one that just causes
1457control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1458<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1459<p>The '<tt>ret</tt>' instruction may return any '<a
1460 href="#t_firstclass">first class</a>' type. Notice that a function is
1461not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1462instruction inside of the function that returns a value that does not
1463match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1464<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1465<p>When the '<tt>ret</tt>' instruction is executed, control flow
1466returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1467 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1468the instruction after the call. If the caller was an "<a
1469 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1470at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1471returns a value, that value shall set the call or invoke instruction's
1472return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1473<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1474<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1475 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1476</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1477</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1478<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1479<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1480<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1481<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1482<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 Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1483</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1484<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1485<p>The '<tt>br</tt>' instruction is used to cause control flow to
1486transfer to a different basic block in the current function. There are
1487two forms of this instruction, corresponding to a conditional branch
1488and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1489<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1490<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1491single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1492unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1493value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1494<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1495<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1496argument is evaluated. If the value is <tt>true</tt>, control flows
1497to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1498control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1499<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1500<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br bool %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
1501 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1502</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1503<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1504<div class="doc_subsubsection">
1505 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1506</div>
1507
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1508<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1509<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1510
1511<pre>
1512 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1513</pre>
1514
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1515<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1516
1517<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1518several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1519instruction, allowing a branch to occur to one of many possible
1520destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1521
1522
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1523<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1524
1525<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1526comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1527an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1528table is not allowed to contain duplicate constant entries.</p>
1529
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1530<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1531
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1532<p>The <tt>switch</tt> instruction specifies a table of values and
1533destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1534table is searched for the given value. If the value is found, control flow is
1535transfered to the corresponding destination; otherwise, control flow is
1536transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1537
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1538<h5>Implementation:</h5>
1539
1540<p>Depending on properties of the target machine and the particular
1541<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1542ways. For example, it could be generated as a series of chained conditional
1543branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1544
1545<h5>Example:</h5>
1546
1547<pre>
1548 <i>; Emulate a conditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1549 %Val = <a href="#i_zext">zext</a> bool %value to i32
1550 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1551
1552 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1553 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1554
1555 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1556 switch i32 %val, label %otherwise [ i32 0, label %onzero
1557 i32 1, label %onone
1558 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1559</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1560</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1561
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1562<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1563<div class="doc_subsubsection">
1564 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1565</div>
1566
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1567<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1568
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1569<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1570
1571<pre>
1572 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] &lt;ptr to function ty&gt; %&lt;function ptr val&gt;(&lt;function args&gt;)
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]1573 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1574</pre>
1575
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1576<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1577
1578<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1579function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1580'<tt>normal</tt>' label or the
1581'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1582"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1583"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1584href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1585continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1586
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1587<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1588
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1589<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1590
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1591<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1592 <li>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1593 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1594 convention</a> the call should use. If none is specified, the call defaults
1595 to using C calling conventions.
1596 </li>
1597 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1598 function value being invoked. In most cases, this is a direct function
1599 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1600 an arbitrary pointer to function value.
1601 </li>
1602
1603 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1604 function to be invoked. </li>
1605
1606 <li>'<tt>function args</tt>': argument list whose types match the function
1607 signature argument types. If the function signature indicates the function
1608 accepts a variable number of arguments, the extra arguments can be
1609 specified. </li>
1610
1611 <li>'<tt>normal label</tt>': the label reached when the called function
1612 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1613
1614 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1615 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1616
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1617</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1618
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1619<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1620
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1621<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1622href="#i_call">call</a></tt>' instruction in most regards. The primary
1623difference is that it establishes an association with a label, which is used by
1624the runtime library to unwind the stack.</p>
1625
1626<p>This instruction is used in languages with destructors to ensure that proper
1627cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1628exception. Additionally, this is important for implementation of
1629'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1630
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1631<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1632<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1633 %retval = invoke i32 %Test(i32 15) to label %Continue
1634 unwind label %TestCleanup <i>; {i32}:retval set</i>
1635 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1636 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1637</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1638</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1639
1640
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1641<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1642
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1643<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1644Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1645
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1646<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1647
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1648<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1649<pre>
1650 unwind
1651</pre>
1652
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1653<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1654
1655<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1656at the first callee in the dynamic call stack which used an <a
1657href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1658primarily used to implement exception handling.</p>
1659
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1660<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1661
1662<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1663immediately halt. The dynamic call stack is then searched for the first <a
1664href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1665execution continues at the "exceptional" destination block specified by the
1666<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1667dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1668</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1669
1670<!-- _______________________________________________________________________ -->
1671
1672<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1673Instruction</a> </div>
1674
1675<div class="doc_text">
1676
1677<h5>Syntax:</h5>
1678<pre>
1679 unreachable
1680</pre>
1681
1682<h5>Overview:</h5>
1683
1684<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1685instruction is used to inform the optimizer that a particular portion of the
1686code is not reachable. This can be used to indicate that the code after a
1687no-return function cannot be reached, and other facts.</p>
1688
1689<h5>Semantics:</h5>
1690
1691<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1692</div>
1693
1694
1695
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1696<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1697<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1698<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1699<p>Binary operators are used to do most of the computation in a
1700program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1701produce a single value. The operands might represent
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1702multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1703The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1704necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1705<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1706</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1707<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1708<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1709Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1710<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1712<pre> &lt;result&gt; = add &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1713</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1715<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1716<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1717<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1718 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1719 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1720Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1721<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1722<p>The value produced is the integer or floating point sum of the two
1723operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1724<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1725<pre> &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1726</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1727</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1728<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1729<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1730Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1731<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1732<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1733<pre> &lt;result&gt; = sub &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1734</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1735<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1736<p>The '<tt>sub</tt>' instruction returns the difference of its two
1737operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1738<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1739instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1740<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1741<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1742 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1743values.
1744This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1745Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1747<p>The value produced is the integer or floating point difference of
1748the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1749<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1750<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1751 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1752</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1755<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1756Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1757<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1758<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1759<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1760</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1761<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1762<p>The '<tt>mul</tt>' instruction returns the product of its two
1763operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1764<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1765<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1766 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1767values.
1768This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1769Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1770<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1771<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1772two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1773<p>There is no signed vs unsigned multiplication. The appropriate
1774action is taken based on the type of the operand.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1775<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1776<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1777</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1778</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1779<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1780<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1781</a></div>
1782<div class="doc_text">
1783<h5>Syntax:</h5>
1784<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1785</pre>
1786<h5>Overview:</h5>
1787<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1788operands.</p>
1789<h5>Arguments:</h5>
1790<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1791<a href="#t_integer">integer</a> values. Both arguments must have identical
1792types. This instruction can also take <a href="#t_packed">packed</a> versions
1793of the values in which case the elements must be integers.</p>
1794<h5>Semantics:</h5>
1795<p>The value produced is the unsigned integer quotient of the two operands. This
1796instruction always performs an unsigned division operation, regardless of
1797whether the arguments are unsigned or not.</p>
1798<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1799<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1800</pre>
1801</div>
1802<!-- _______________________________________________________________________ -->
1803<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1804</a> </div>
1805<div class="doc_text">
1806<h5>Syntax:</h5>
1807<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1808</pre>
1809<h5>Overview:</h5>
1810<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1811operands.</p>
1812<h5>Arguments:</h5>
1813<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1814<a href="#t_integer">integer</a> values. Both arguments must have identical
1815types. This instruction can also take <a href="#t_packed">packed</a> versions
1816of the values in which case the elements must be integers.</p>
1817<h5>Semantics:</h5>
1818<p>The value produced is the signed integer quotient of the two operands. This
1819instruction always performs a signed division operation, regardless of whether
1820the arguments are signed or not.</p>
1821<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1822<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1823</pre>
1824</div>
1825<!-- _______________________________________________________________________ -->
1826<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1827Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1828<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1829<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1830<pre> &lt;result&gt; = fdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1831</pre>
1832<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1833<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1834operands.</p>
1835<h5>Arguments:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1836<p>The two arguments to the '<tt>div</tt>' instruction must be
1837<a href="#t_floating">floating point</a> values. Both arguments must have
1838identical types. This instruction can also take <a href="#t_packed">packed</a>
1839versions of the values in which case the elements must be floating point.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1840<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1841<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1842<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1843<pre> &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1844</pre>
1845</div>
1846<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1847<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1848</div>
1849<div class="doc_text">
1850<h5>Syntax:</h5>
1851<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1852</pre>
1853<h5>Overview:</h5>
1854<p>The '<tt>urem</tt>' instruction returns the remainder from the
1855unsigned division of its two arguments.</p>
1856<h5>Arguments:</h5>
1857<p>The two arguments to the '<tt>urem</tt>' instruction must be
1858<a href="#t_integer">integer</a> values. Both arguments must have identical
1859types.</p>
1860<h5>Semantics:</h5>
1861<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1862This instruction always performs an unsigned division to get the remainder,
1863regardless of whether the arguments are unsigned or not.</p>
1864<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1865<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1866</pre>
1867
1868</div>
1869<!-- _______________________________________________________________________ -->
1870<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1871Instruction</a> </div>
1872<div class="doc_text">
1873<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1874<pre> &lt;result&gt; = srem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1875</pre>
1876<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1877<p>The '<tt>srem</tt>' instruction returns the remainder from the
1878signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1879<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1880<p>The two arguments to the '<tt>srem</tt>' instruction must be
1881<a href="#t_integer">integer</a> values. Both arguments must have identical
1882types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1883<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1884<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1885has the same sign as the divisor), not the <i>modulus</i> (where the
1886result has the same sign as the dividend) of a value. For more
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1887information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1888 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1889Math Forum</a>.</p>
1890<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1891<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1892</pre>
1893
1894</div>
1895<!-- _______________________________________________________________________ -->
1896<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1897Instruction</a> </div>
1898<div class="doc_text">
1899<h5>Syntax:</h5>
1900<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1901</pre>
1902<h5>Overview:</h5>
1903<p>The '<tt>frem</tt>' instruction returns the remainder from the
1904division of its two operands.</p>
1905<h5>Arguments:</h5>
1906<p>The two arguments to the '<tt>frem</tt>' instruction must be
1907<a href="#t_floating">floating point</a> values. Both arguments must have
1908identical types.</p>
1909<h5>Semantics:</h5>
1910<p>This instruction returns the <i>remainder</i> of a division.</p>
1911<h5>Example:</h5>
1912<pre> &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1913</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1914</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]1915
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1916<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1917<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1918Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1919<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1920<p>Bitwise binary operators are used to do various forms of
1921bit-twiddling in a program. They are generally very efficient
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1922instructions and can commonly be strength reduced from other
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1923instructions. They require two operands, execute an operation on them,
1924and produce a single value. The resulting value of the bitwise binary
1925operators is always the same type as its first operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1926</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1927<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1928<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1929Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1930<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1931<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1932<pre> &lt;result&gt; = and &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1933</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1934<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1935<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1936its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1937<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1938<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1939 href="#t_integral">integral</a> values. Both arguments must have
1940identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1941<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1942<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1943<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1944<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1945<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1946 <tbody>
1947 <tr>
1948 <td>In0</td>
1949 <td>In1</td>
1950 <td>Out</td>
1951 </tr>
1952 <tr>
1953 <td>0</td>
1954 <td>0</td>
1955 <td>0</td>
1956 </tr>
1957 <tr>
1958 <td>0</td>
1959 <td>1</td>
1960 <td>0</td>
1961 </tr>
1962 <tr>
1963 <td>1</td>
1964 <td>0</td>
1965 <td>0</td>
1966 </tr>
1967 <tr>
1968 <td>1</td>
1969 <td>1</td>
1970 <td>1</td>
1971 </tr>
1972 </tbody>
1973</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1974</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1975<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1976<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1977 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
1978 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1979</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1980</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1981<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1982<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1983<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1984<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1985<pre> &lt;result&gt; = or &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1986</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1987<h5>Overview:</h5>
1988<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
1989or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1990<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1991<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1992 href="#t_integral">integral</a> values. Both arguments must have
1993identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1994<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1995<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1996<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1997<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1998<table border="1" cellspacing="0" cellpadding="4">
1999 <tbody>
2000 <tr>
2001 <td>In0</td>
2002 <td>In1</td>
2003 <td>Out</td>
2004 </tr>
2005 <tr>
2006 <td>0</td>
2007 <td>0</td>
2008 <td>0</td>
2009 </tr>
2010 <tr>
2011 <td>0</td>
2012 <td>1</td>
2013 <td>1</td>
2014 </tr>
2015 <tr>
2016 <td>1</td>
2017 <td>0</td>
2018 <td>1</td>
2019 </tr>
2020 <tr>
2021 <td>1</td>
2022 <td>1</td>
2023 <td>1</td>
2024 </tr>
2025 </tbody>
2026</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2027</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2028<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2029<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2030 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2031 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2032</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2033</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2034<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2035<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2036Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2037<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2038<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2039<pre> &lt;result&gt; = xor &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2040</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2041<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2042<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2043or of its two operands. The <tt>xor</tt> is used to implement the
2044"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2045<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2046<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2047 href="#t_integral">integral</a> values. Both arguments must have
2048identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2049<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2050<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2051<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2052<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2053<table border="1" cellspacing="0" cellpadding="4">
2054 <tbody>
2055 <tr>
2056 <td>In0</td>
2057 <td>In1</td>
2058 <td>Out</td>
2059 </tr>
2060 <tr>
2061 <td>0</td>
2062 <td>0</td>
2063 <td>0</td>
2064 </tr>
2065 <tr>
2066 <td>0</td>
2067 <td>1</td>
2068 <td>1</td>
2069 </tr>
2070 <tr>
2071 <td>1</td>
2072 <td>0</td>
2073 <td>1</td>
2074 </tr>
2075 <tr>
2076 <td>1</td>
2077 <td>1</td>
2078 <td>0</td>
2079 </tr>
2080 </tbody>
2081</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2082</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2083<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2084<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2085<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2086 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2087 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2088 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2089</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2090</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2091<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2092<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2093Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2094<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2095<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2096<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2097</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2098<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2099<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2100the left a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2101<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2102<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2103 href="#t_integer">integer</a> type. The second argument must be an '<tt>i8</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2104type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2105<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2106<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2107<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2108<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2109 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2110 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2111</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2112</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2113<!-- _______________________________________________________________________ -->
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2114<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2115Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2116<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2117<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2118<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2119</pre>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2120
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2121<h5>Overview:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2122<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2123operand shifted to the right a specified number of bits.</p>
2124
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2125<h5>Arguments:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2126<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2127 href="#t_integer">integer</a> type. The second argument must be an '<tt>i8</tt>' type.</p>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2128
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2129<h5>Semantics:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2130<p>This instruction always performs a logical shift right operation, regardless
2131of whether the arguments are unsigned or not. The <tt>var2</tt> most significant
2132bits will be filled with zero bits after the shift.</p>
2133
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2134<h5>Example:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2135<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2136 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2137 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2138 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2139 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2140</pre>
2141</div>
2142
2143<!-- ======================================================================= -->
2144<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2145Instruction</a> </div>
2146<div class="doc_text">
2147
2148<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2149<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, i8 &lt;var2&gt; <i>; yields {ty}:result</i>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2150</pre>
2151
2152<h5>Overview:</h5>
2153<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2154operand shifted to the right a specified number of bits.</p>
2155
2156<h5>Arguments:</h5>
2157<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2158<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2159'<tt>i8</tt>' type.</p>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2160
2161<h5>Semantics:</h5>
2162<p>This instruction always performs an arithmetic shift right operation,
2163regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2164significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2165
2166<h5>Example:</h5>
2167<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2168 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2169 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2170 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2171 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2172</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2173</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2174
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2175<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2176<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2177 <a name="vectorops">Vector Operations</a>
2178</div>
2179
2180<div class="doc_text">
2181
2182<p>LLVM supports several instructions to represent vector operations in a
2183target-independent manner. This instructions cover the element-access and
2184vector-specific operations needed to process vectors effectively. While LLVM
2185does directly support these vector operations, many sophisticated algorithms
2186will want to use target-specific intrinsics to take full advantage of a specific
2187target.</p>
2188
2189</div>
2190
2191<!-- _______________________________________________________________________ -->
2192<div class="doc_subsubsection">
2193 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2194</div>
2195
2196<div class="doc_text">
2197
2198<h5>Syntax:</h5>
2199
2200<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2201 &lt;result&gt; = extractelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, i32 &lt;idx&gt; <i>; yields &lt;ty&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2202</pre>
2203
2204<h5>Overview:</h5>
2205
2206<p>
2207The '<tt>extractelement</tt>' instruction extracts a single scalar
2208element from a packed vector at a specified index.
2209</p>
2210
2211
2212<h5>Arguments:</h5>
2213
2214<p>
2215The first operand of an '<tt>extractelement</tt>' instruction is a
2216value of <a href="#t_packed">packed</a> type. The second operand is
2217an index indicating the position from which to extract the element.
2218The index may be a variable.</p>
2219
2220<h5>Semantics:</h5>
2221
2222<p>
2223The result is a scalar of the same type as the element type of
2224<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2225<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2226results are undefined.
2227</p>
2228
2229<h5>Example:</h5>
2230
2231<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2232 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2233</pre>
2234</div>
2235
2236
2237<!-- _______________________________________________________________________ -->
2238<div class="doc_subsubsection">
2239 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2240</div>
2241
2242<div class="doc_text">
2243
2244<h5>Syntax:</h5>
2245
2246<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2247 &lt;result&gt; = insertelement &lt;n x &lt;ty&gt;&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt, i32 &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2248</pre>
2249
2250<h5>Overview:</h5>
2251
2252<p>
2253The '<tt>insertelement</tt>' instruction inserts a scalar
2254element into a packed vector at a specified index.
2255</p>
2256
2257
2258<h5>Arguments:</h5>
2259
2260<p>
2261The first operand of an '<tt>insertelement</tt>' instruction is a
2262value of <a href="#t_packed">packed</a> type. The second operand is a
2263scalar value whose type must equal the element type of the first
2264operand. The third operand is an index indicating the position at
2265which to insert the value. The index may be a variable.</p>
2266
2267<h5>Semantics:</h5>
2268
2269<p>
2270The result is a packed vector of the same type as <tt>val</tt>. Its
2271element values are those of <tt>val</tt> except at position
2272<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2273exceeds the length of <tt>val</tt>, the results are undefined.
2274</p>
2275
2276<h5>Example:</h5>
2277
2278<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2279 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2280</pre>
2281</div>
2282
2283<!-- _______________________________________________________________________ -->
2284<div class="doc_subsubsection">
2285 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2286</div>
2287
2288<div class="doc_text">
2289
2290<h5>Syntax:</h5>
2291
2292<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2293 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;n x i32&gt; &lt;mask&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2294</pre>
2295
2296<h5>Overview:</h5>
2297
2298<p>
2299The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2300from two input vectors, returning a vector of the same type.
2301</p>
2302
2303<h5>Arguments:</h5>
2304
2305<p>
2306The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2307with types that match each other and types that match the result of the
2308instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2309of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2310</p>
2311
2312<p>
2313The shuffle mask operand is required to be a constant vector with either
2314constant integer or undef values.
2315</p>
2316
2317<h5>Semantics:</h5>
2318
2319<p>
2320The elements of the two input vectors are numbered from left to right across
2321both of the vectors. The shuffle mask operand specifies, for each element of
2322the result vector, which element of the two input registers the result element
2323gets. The element selector may be undef (meaning "don't care") and the second
2324operand may be undef if performing a shuffle from only one vector.
2325</p>
2326
2327<h5>Example:</h5>
2328
2329<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2330 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2331 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2332 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2333 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i> - Identity shuffle.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2334</pre>
2335</div>
2336
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2337
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2338<!-- ======================================================================= -->
2339<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2340 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2341</div>
2342
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2343<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2344
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2345<p>A key design point of an SSA-based representation is how it
2346represents memory. In LLVM, no memory locations are in SSA form, which
2347makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2348allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2349
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2350</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2351
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2352<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2353<div class="doc_subsubsection">
2354 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2355</div>
2356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2357<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2359<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2360
2361<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2362 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2363</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2364
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2365<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2366
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2367<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2368heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2369
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2370<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2371
2372<p>The '<tt>malloc</tt>' instruction allocates
2373<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2374bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2375appropriate type to the program. If "NumElements" is specified, it is the
2376number of elements allocated. If an alignment is specified, the value result
2377of the allocation is guaranteed to be aligned to at least that boundary. If
2378not specified, or if zero, the target can choose to align the allocation on any
2379convenient boundary.</p>
2380
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2381<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2382
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2383<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2384
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2385<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2386a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2387
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2388<h5>Example:</h5>
2389
2390<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2391 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2392
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2393 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2394 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2395 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2396 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2397 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2398</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2399</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2400
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2401<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2402<div class="doc_subsubsection">
2403 <a name="i_free">'<tt>free</tt>' Instruction</a>
2404</div>
2405
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2406<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2407
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2408<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2409
2410<pre>
2411 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2412</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2413
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2414<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2415
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2416<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2417memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2419<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2420
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2421<p>'<tt>value</tt>' shall be a pointer value that points to a value
2422that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2423instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2424
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2425<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2426
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2427<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2428after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2429
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2430<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2431
2432<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2433 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2434 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2435</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2436</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2437
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2438<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2439<div class="doc_subsubsection">
2440 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2441</div>
2442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2443<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2445<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2446
2447<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2448 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2449</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2450
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2451<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2452
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2453<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2454stack frame of the procedure that is live until the current function
2455returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2456
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2457<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2458
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2459<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2460bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2461appropriate type to the program. If "NumElements" is specified, it is the
2462number of elements allocated. If an alignment is specified, the value result
2463of the allocation is guaranteed to be aligned to at least that boundary. If
2464not specified, or if zero, the target can choose to align the allocation on any
2465convenient boundary.</p>
2466
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2467<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2468
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2469<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2470
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2471<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2472memory is automatically released when the function returns. The '<tt>alloca</tt>'
2473instruction is commonly used to represent automatic variables that must
2474have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2475 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2476instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2477
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2478<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2479
2480<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2481 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2482 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2483 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2484 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2485</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2486</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2487
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2488<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2489<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2490Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2491<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2492<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2493<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 Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2494<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2495<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2496<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2497<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2498address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2499 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2500marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2501the number or order of execution of this <tt>load</tt> with other
2502volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2503instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2504<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2505<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2506<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2507<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2508 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2509 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2510 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2511</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2512</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2513<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2514<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2515Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2516<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2517<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2518<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner12d456c2003-09-08 18:27:49 +0000[diff] [blame]2519 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2520</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2521<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2522<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2523<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2524<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2525to store and an address in which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2526operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2527operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2528optimizer is not allowed to modify the number or order of execution of
2529this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2530 href="#i_store">store</a></tt> instructions.</p>
2531<h5>Semantics:</h5>
2532<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2533at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2534<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2535<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2536 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2537 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2538 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2539</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2540</div>
2541
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2542<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2543<div class="doc_subsubsection">
2544 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2545</div>
2546
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2547<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2548<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2549<pre>
2550 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2551</pre>
2552
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2553<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2554
2555<p>
2556The '<tt>getelementptr</tt>' instruction is used to get the address of a
2557subelement of an aggregate data structure.</p>
2558
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2559<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2560
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2561<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2562elements of the aggregate object to index to. The actual types of the arguments
2563provided depend on the type of the first pointer argument. The
2564'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2565levels of a structure or to a specific index in an array. When indexing into a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2566structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2567into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2568be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2569
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2570<p>For example, let's consider a C code fragment and how it gets
2571compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2572
2573<pre>
2574 struct RT {
2575 char A;
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2576 i32 B[10][20];
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2577 char C;
2578 };
2579 struct ST {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2580 i32 X;
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2581 double Y;
2582 struct RT Z;
2583 };
2584
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2585 define i32 *foo(struct ST *s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2586 return &amp;s[1].Z.B[5][13];
2587 }
2588</pre>
2589
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2590<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2591
2592<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2593 %RT = type { i8 , [10 x [20 x i32]], i8 }
2594 %ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2595
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2596 implementation
2597
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2598 define i32* %foo(%ST* %s) {
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2599 entry:
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2600 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2601 ret i32* %reg
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2602 }
2603</pre>
2604
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2605<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2606
2607<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2608on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2609and <a href="#t_array">array</a> types can use a 32-bit or 64-bit
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2610<a href="#t_integer">integer</a> type but the value will always be sign extended
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2611to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2612<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2613
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2614<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2615type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2616}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2617the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2618i8 }</tt>' type, another structure. The third index indexes into the second
2619element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2620array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2621'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2622to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2623
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2624<p>Note that it is perfectly legal to index partially through a
2625structure, returning a pointer to an inner element. Because of this,
2626the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2627
2628<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2629 define i32* %foo(%ST* %s) {
2630 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2631 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2632 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2633 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2634 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2635 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2636 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2637</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2638
2639<p>Note that it is undefined to access an array out of bounds: array and
2640pointer indexes must always be within the defined bounds of the array type.
2641The one exception for this rules is zero length arrays. These arrays are
2642defined to be accessible as variable length arrays, which requires access
2643beyond the zero'th element.</p>
2644
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2645<p>The getelementptr instruction is often confusing. For some more insight
2646into how it works, see <a href="GetElementPtr.html">the getelementptr
2647FAQ</a>.</p>
2648
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2649<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2650
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2651<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2652 <i>; yields [12 x i8]*:aptr</i>
2653 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2654</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2655</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2656
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2657<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2658<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2659</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2660<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2661<p>The instructions in this category are the conversion instructions (casting)
2662which all take a single operand and a type. They perform various bit conversions
2663on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2664</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2665
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2666<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2667<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2668 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2669</div>
2670<div class="doc_text">
2671
2672<h5>Syntax:</h5>
2673<pre>
2674 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2675</pre>
2676
2677<h5>Overview:</h5>
2678<p>
2679The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2680</p>
2681
2682<h5>Arguments:</h5>
2683<p>
2684The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2685be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2686and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2687type. The bit size of <tt>value</tt> must be larger than the bit size of
2688<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2689
2690<h5>Semantics:</h5>
2691<p>
2692The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2693and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2694larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2695It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2696
2697<h5>Example:</h5>
2698<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2699 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
2700 %Y = trunc i32 123 to bool <i>; yields bool:true</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2701</pre>
2702</div>
2703
2704<!-- _______________________________________________________________________ -->
2705<div class="doc_subsubsection">
2706 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2707</div>
2708<div class="doc_text">
2709
2710<h5>Syntax:</h5>
2711<pre>
2712 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2713</pre>
2714
2715<h5>Overview:</h5>
2716<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2717<tt>ty2</tt>.</p>
2718
2719
2720<h5>Arguments:</h5>
2721<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2722<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2723also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2724<tt>value</tt> must be smaller than the bit size of the destination type,
2725<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2726
2727<h5>Semantics:</h5>
2728<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2729bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2730the operand and the type are the same size, no bit filling is done and the
2731cast is considered a <i>no-op cast</i> because no bits change (only the type
2732changes).</p>
2733
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2734<p>When zero extending from bool, the result will alwasy be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2735
2736<h5>Example:</h5>
2737<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2738 %X = zext i32 257 to i64 <i>; yields i64:257</i>
2739 %Y = zext bool true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2740</pre>
2741</div>
2742
2743<!-- _______________________________________________________________________ -->
2744<div class="doc_subsubsection">
2745 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2746</div>
2747<div class="doc_text">
2748
2749<h5>Syntax:</h5>
2750<pre>
2751 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2752</pre>
2753
2754<h5>Overview:</h5>
2755<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2756
2757<h5>Arguments:</h5>
2758<p>
2759The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2760<a href="#t_integral">integral</a> type, and a type to cast it to, which must
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2761also be of <a href="#t_integral">integral</a> type. The bit size of the
2762<tt>value</tt> must be smaller than the bit size of the destination type,
2763<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2764
2765<h5>Semantics:</h5>
2766<p>
2767The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2768bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2769the type <tt>ty2</tt>. When the the operand and the type are the same size,
2770no bit filling is done and the cast is considered a <i>no-op cast</i> because
2771no bits change (only the type changes).</p>
2772
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2773<p>When sign extending from bool, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2774
2775<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2776<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2777 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
2778 %Y = sext bool true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2779</pre>
2780</div>
2781
2782<!-- _______________________________________________________________________ -->
2783<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2784 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2785</div>
2786
2787<div class="doc_text">
2788
2789<h5>Syntax:</h5>
2790
2791<pre>
2792 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2793</pre>
2794
2795<h5>Overview:</h5>
2796<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2797<tt>ty2</tt>.</p>
2798
2799
2800<h5>Arguments:</h5>
2801<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2802 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2803cast it to. The size of <tt>value</tt> must be larger than the size of
2804<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2805<i>no-op cast</i>.</p>
2806
2807<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2808<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2809<a href="#t_floating">floating point</a> type to a smaller
2810<a href="#t_floating">floating point</a> type. If the value cannot fit within
2811the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2812
2813<h5>Example:</h5>
2814<pre>
2815 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2816 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2817</pre>
2818</div>
2819
2820<!-- _______________________________________________________________________ -->
2821<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2822 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2823</div>
2824<div class="doc_text">
2825
2826<h5>Syntax:</h5>
2827<pre>
2828 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2829</pre>
2830
2831<h5>Overview:</h5>
2832<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2833floating point value.</p>
2834
2835<h5>Arguments:</h5>
2836<p>The '<tt>fpext</tt>' instruction takes a
2837<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2838and a <a href="#t_floating">floating point</a> type to cast it to. The source
2839type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2840
2841<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2842<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2843<a href="t_floating">floating point</a> type to a larger
2844<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2845used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2846<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2847
2848<h5>Example:</h5>
2849<pre>
2850 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2851 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2852</pre>
2853</div>
2854
2855<!-- _______________________________________________________________________ -->
2856<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2857 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2858</div>
2859<div class="doc_text">
2860
2861<h5>Syntax:</h5>
2862<pre>
2863 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2864</pre>
2865
2866<h5>Overview:</h5>
2867<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2868unsigned integer equivalent of type <tt>ty2</tt>.
2869</p>
2870
2871<h5>Arguments:</h5>
2872<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2873<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2874must be an <a href="#t_integral">integral</a> type.</p>
2875
2876<h5>Semantics:</h5>
2877<p> The '<tt>fp2uint</tt>' instruction converts its
2878<a href="#t_floating">floating point</a> operand into the nearest (rounding
2879towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2880the results are undefined.</p>
2881
2882<p>When converting to bool, the conversion is done as a comparison against
2883zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2884If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2885
2886<h5>Example:</h5>
2887<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2888 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2889 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2890 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2891</pre>
2892</div>
2893
2894<!-- _______________________________________________________________________ -->
2895<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2896 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2897</div>
2898<div class="doc_text">
2899
2900<h5>Syntax:</h5>
2901<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2902 &lt;result&gt; = fptosi &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2903</pre>
2904
2905<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2906<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2907<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2908</p>
2909
2910
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2911<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2912<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2913<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2914must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2915
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2916<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2917<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2918<a href="#t_floating">floating point</a> operand into the nearest (rounding
2919towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2920the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2921
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2922<p>When converting to bool, the conversion is done as a comparison against
2923zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2924If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2925
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2926<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2927<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2928 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2929 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2930 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2931</pre>
2932</div>
2933
2934<!-- _______________________________________________________________________ -->
2935<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2936 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2937</div>
2938<div class="doc_text">
2939
2940<h5>Syntax:</h5>
2941<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2942 &lt;result&gt; = uitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2943</pre>
2944
2945<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2946<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2947integer and converts that value to the <tt>ty2</tt> type.</p>
2948
2949
2950<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2951<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2952<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2953be a <a href="#t_floating">floating point</a> type.</p>
2954
2955<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2956<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2957integer quantity and converts it to the corresponding floating point value. If
2958the value cannot fit in the floating point value, the results are undefined.</p>
2959
2960
2961<h5>Example:</h5>
2962<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2963 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2964 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2965</pre>
2966</div>
2967
2968<!-- _______________________________________________________________________ -->
2969<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2970 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2971</div>
2972<div class="doc_text">
2973
2974<h5>Syntax:</h5>
2975<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2976 &lt;result&gt; = sitofp &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2977</pre>
2978
2979<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2980<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2981integer and converts that value to the <tt>ty2</tt> type.</p>
2982
2983<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2984<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2985<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
2986a <a href="#t_floating">floating point</a> type.</p>
2987
2988<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2989<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2990integer quantity and converts it to the corresponding floating point value. If
2991the value cannot fit in the floating point value, the results are undefined.</p>
2992
2993<h5>Example:</h5>
2994<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2995 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
2996 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2997</pre>
2998</div>
2999
3000<!-- _______________________________________________________________________ -->
3001<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3002 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3003</div>
3004<div class="doc_text">
3005
3006<h5>Syntax:</h5>
3007<pre>
3008 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3009</pre>
3010
3011<h5>Overview:</h5>
3012<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3013the integer type <tt>ty2</tt>.</p>
3014
3015<h5>Arguments:</h5>
3016<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3017must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3018<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3019
3020<h5>Semantics:</h5>
3021<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3022<tt>ty2</tt> by interpreting the pointer value as an integer and either
3023truncating or zero extending that value to the size of the integer type. If
3024<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3025<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3026are the same size, then nothing is done (<i>no-op cast</i>).</p>
3027
3028<h5>Example:</h5>
3029<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3030 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3031 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3032</pre>
3033</div>
3034
3035<!-- _______________________________________________________________________ -->
3036<div class="doc_subsubsection">
3037 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3038</div>
3039<div class="doc_text">
3040
3041<h5>Syntax:</h5>
3042<pre>
3043 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3044</pre>
3045
3046<h5>Overview:</h5>
3047<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3048a pointer type, <tt>ty2</tt>.</p>
3049
3050<h5>Arguments:</h5>
3051<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3052value to cast, and a type to cast it to, which must be a
3053<a href="#t_pointer">pointer</a> type. </tt>
3054
3055<h5>Semantics:</h5>
3056<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3057<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3058the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3059size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3060the size of a pointer then a zero extension is done. If they are the same size,
3061nothing is done (<i>no-op cast</i>).</p>
3062
3063<h5>Example:</h5>
3064<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3065 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3066 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3067 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3068</pre>
3069</div>
3070
3071<!-- _______________________________________________________________________ -->
3072<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3073 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3074</div>
3075<div class="doc_text">
3076
3077<h5>Syntax:</h5>
3078<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3079 &lt;result&gt; = bitcast &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3080</pre>
3081
3082<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3083<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3084<tt>ty2</tt> without changing any bits.</p>
3085
3086<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3087<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3088a first class value, and a type to cast it to, which must also be a <a
3089 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3090and the destination type, <tt>ty2</tt>, must be identical.</p>
3091
3092<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3093<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3094<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3095this conversion. The conversion is done as if the <tt>value</tt> had been
3096stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3097converted to other pointer types with this instruction. To convert pointers to
3098other types, use the <a href="#i_inttoptr">inttoptr</a> or
3099<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3100
3101<h5>Example:</h5>
3102<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3103 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3104 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3105 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3106</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3107</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3108
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3109<!-- ======================================================================= -->
3110<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3111<div class="doc_text">
3112<p>The instructions in this category are the "miscellaneous"
3113instructions, which defy better classification.</p>
3114</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3115
3116<!-- _______________________________________________________________________ -->
3117<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3118</div>
3119<div class="doc_text">
3120<h5>Syntax:</h5>
3121<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3122</pre>
3123<h5>Overview:</h5>
3124<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3125of its two integer operands.</p>
3126<h5>Arguments:</h5>
3127<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3128the condition code which indicates the kind of comparison to perform. It is not
3129a value, just a keyword. The possibilities for the condition code are:
3130<ol>
3131 <li><tt>eq</tt>: equal</li>
3132 <li><tt>ne</tt>: not equal </li>
3133 <li><tt>ugt</tt>: unsigned greater than</li>
3134 <li><tt>uge</tt>: unsigned greater or equal</li>
3135 <li><tt>ult</tt>: unsigned less than</li>
3136 <li><tt>ule</tt>: unsigned less or equal</li>
3137 <li><tt>sgt</tt>: signed greater than</li>
3138 <li><tt>sge</tt>: signed greater or equal</li>
3139 <li><tt>slt</tt>: signed less than</li>
3140 <li><tt>sle</tt>: signed less or equal</li>
3141</ol>
3142<p>The remaining two arguments must be of <a href="#t_integral">integral</a>,
3143<a href="#t_pointer">pointer</a> or a <a href="#t_packed">packed</a> integral
3144type. They must have identical types.</p>
3145<h5>Semantics:</h5>
3146<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3147the condition code given as <tt>cond</tt>. The comparison performed always
3148yields a <a href="#t_bool">bool</a> result, as follows:
3149<ol>
3150 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3151 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3152 </li>
3153 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3154 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3155 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3156 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3157 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3158 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3159 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3160 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3161 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3162 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3163 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3164 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3165 <li><tt>sge</tt>: interprets the operands as signed values and yields
3166 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3167 <li><tt>slt</tt>: interprets the operands as signed values and yields
3168 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3169 <li><tt>sle</tt>: interprets the operands as signed values and yields
3170 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3171 </li>
3172</ol>
3173<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3174values are treated as integers and then compared.</p>
3175<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3176the vector are compared in turn and the predicate must hold for all
3177elements.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3178
3179<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3180<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3181 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3182 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3183 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3184 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3185 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3186</pre>
3187</div>
3188
3189<!-- _______________________________________________________________________ -->
3190<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3191</div>
3192<div class="doc_text">
3193<h5>Syntax:</h5>
3194<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3195</pre>
3196<h5>Overview:</h5>
3197<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3198of its floating point operands.</p>
3199<h5>Arguments:</h5>
3200<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3201the condition code which indicates the kind of comparison to perform. It is not
3202a value, just a keyword. The possibilities for the condition code are:
3203<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3204 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3205 <li><tt>oeq</tt>: ordered and equal</li>
3206 <li><tt>ogt</tt>: ordered and greater than </li>
3207 <li><tt>oge</tt>: ordered and greater than or equal</li>
3208 <li><tt>olt</tt>: ordered and less than </li>
3209 <li><tt>ole</tt>: ordered and less than or equal</li>
3210 <li><tt>one</tt>: ordered and not equal</li>
3211 <li><tt>ord</tt>: ordered (no nans)</li>
3212 <li><tt>ueq</tt>: unordered or equal</li>
3213 <li><tt>ugt</tt>: unordered or greater than </li>
3214 <li><tt>uge</tt>: unordered or greater than or equal</li>
3215 <li><tt>ult</tt>: unordered or less than </li>
3216 <li><tt>ule</tt>: unordered or less than or equal</li>
3217 <li><tt>une</tt>: unordered or not equal</li>
3218 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3219 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3220</ol>
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3221<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3222<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3223<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be of
3224<a href="#t_floating">floating point</a>, or a <a href="#t_packed">packed</a>
3225floating point type. They must have identical types.</p>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3226<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3227<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3228<h5>Semantics:</h5>
3229<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3230the condition code given as <tt>cond</tt>. The comparison performed always
3231yields a <a href="#t_bool">bool</a> result, as follows:
3232<ol>
3233 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3234 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3235 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3236 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3237 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3238 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3239 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3240 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3241 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3242 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3243 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3244 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3245 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3246 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3247 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3248 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3249 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3250 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3251 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3252 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3253 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3254 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3255 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3256 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3257 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3258 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3259 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3260 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3261</ol>
3262<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3263the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3264</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3265
3266<h5>Example:</h5>
3267<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3268 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3269 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3270 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3271</pre>
3272</div>
3273
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3274<!-- _______________________________________________________________________ -->
3275<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3276Instruction</a> </div>
3277<div class="doc_text">
3278<h5>Syntax:</h5>
3279<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3280<h5>Overview:</h5>
3281<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3282the SSA graph representing the function.</p>
3283<h5>Arguments:</h5>
3284<p>The type of the incoming values are specified with the first type
3285field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3286as arguments, with one pair for each predecessor basic block of the
3287current block. Only values of <a href="#t_firstclass">first class</a>
3288type may be used as the value arguments to the PHI node. Only labels
3289may be used as the label arguments.</p>
3290<p>There must be no non-phi instructions between the start of a basic
3291block and the PHI instructions: i.e. PHI instructions must be first in
3292a basic block.</p>
3293<h5>Semantics:</h5>
3294<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3295value specified by the parameter, depending on which basic block we
3296came from in the last <a href="#terminators">terminator</a> instruction.</p>
3297<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3298<pre>Loop: ; Infinite loop that counts from 0 on up...<br> %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]<br> %nextindvar = add i32 %indvar, 1<br> br label %Loop<br></pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3299</div>
3300
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3301<!-- _______________________________________________________________________ -->
3302<div class="doc_subsubsection">
3303 <a name="i_select">'<tt>select</tt>' Instruction</a>
3304</div>
3305
3306<div class="doc_text">
3307
3308<h5>Syntax:</h5>
3309
3310<pre>
3311 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3312</pre>
3313
3314<h5>Overview:</h5>
3315
3316<p>
3317The '<tt>select</tt>' instruction is used to choose one value based on a
3318condition, without branching.
3319</p>
3320
3321
3322<h5>Arguments:</h5>
3323
3324<p>
3325The '<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.
3326</p>
3327
3328<h5>Semantics:</h5>
3329
3330<p>
3331If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3332value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3333</p>
3334
3335<h5>Example:</h5>
3336
3337<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3338 %X = select bool true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3339</pre>
3340</div>
3341
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3342
3343<!-- _______________________________________________________________________ -->
3344<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3345 <a name="i_call">'<tt>call</tt>' Instruction</a>
3346</div>
3347
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3348<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3349
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3350<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3351<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3352 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] &lt;ty&gt;* &lt;fnptrval&gt;(&lt;param list&gt;)
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3353</pre>
3354
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3355<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3356
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3357<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3358
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3359<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3360
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3361<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3362
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3363<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3364 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3365 <p>The optional "tail" marker indicates whether the callee function accesses
3366 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3367 function call is eligible for tail call optimization. Note that calls may
3368 be marked "tail" even if they do not occur before a <a
3369 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3370 </li>
3371 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3372 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3373 convention</a> the call should use. If none is specified, the call defaults
3374 to using C calling conventions.
3375 </li>
3376 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3377 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3378 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3379 signature. This type can be omitted if the function is not varargs and
3380 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3381 </li>
3382 <li>
3383 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3384 be invoked. In most cases, this is a direct function invocation, but
3385 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3386 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3387 </li>
3388 <li>
3389 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3390 function signature argument types. All arguments must be of
3391 <a href="#t_firstclass">first class</a> type. If the function signature
3392 indicates the function accepts a variable number of arguments, the extra
3393 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3394 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3395</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3396
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3397<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3398
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3399<p>The '<tt>call</tt>' instruction is used to cause control flow to
3400transfer to a specified function, with its incoming arguments bound to
3401the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3402instruction in the called function, control flow continues with the
3403instruction after the function call, and the return value of the
3404function is bound to the result argument. This is a simpler case of
3405the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3406
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3407<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3408
3409<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3410 %retval = call i32 %test(i32 %argc)
3411 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3412 %X = tail call i32 %foo()
3413 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3414</pre>
3415
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3416</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3417
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3418<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3419<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3420 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3421</div>
3422
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3423<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3424
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3425<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3426
3427<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3428 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3429</pre>
3430
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3431<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3432
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3433<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3434the "variable argument" area of a function call. It is used to implement the
3435<tt>va_arg</tt> macro in C.</p>
3436
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3437<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3438
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3439<p>This instruction takes a <tt>va_list*</tt> value and the type of
3440the argument. It returns a value of the specified argument type and
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]3441increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3442actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3443
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3444<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3445
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3446<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3447type from the specified <tt>va_list</tt> and causes the
3448<tt>va_list</tt> to point to the next argument. For more information,
3449see the variable argument handling <a href="#int_varargs">Intrinsic
3450Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3451
3452<p>It is legal for this instruction to be called in a function which does not
3453take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3454function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3455
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3456<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3457href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3458argument.</p>
3459
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3460<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3461
3462<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3464</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3465
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3466<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3467<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3468<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3469
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3470<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3471
3472<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3473well known names and semantics and are required to follow certain
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3474restrictions. Overall, these instructions represent an extension mechanism for
3475the LLVM language that does not require changing all of the transformations in
3476LLVM to add to the language (or the bytecode reader/writer, the parser,
3477etc...).</p>
3478
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3479<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3480prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3481this. Intrinsic functions must always be external functions: you cannot define
3482the body of intrinsic functions. Intrinsic functions may only be used in call
3483or invoke instructions: it is illegal to take the address of an intrinsic
3484function. Additionally, because intrinsic functions are part of the LLVM
3485language, it is required that they all be documented here if any are added.</p>
3486
3487
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3488<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner90391c12005-05-11 03:35:57 +0000[diff] [blame]3489href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3490</p>
3491
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3492</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3493
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3494<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3495<div class="doc_subsection">
3496 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3497</div>
3498
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3499<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3500
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3501<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3502 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3503intrinsic functions. These functions are related to the similarly
3504named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3505
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3506<p>All of these functions operate on arguments that use a
3507target-specific value type "<tt>va_list</tt>". The LLVM assembly
3508language reference manual does not define what this type is, so all
3509transformations should be prepared to handle intrinsics with any type
3510used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3511
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3512<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3513instruction and the variable argument handling intrinsic functions are
3514used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3515
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3516<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3517define i32 %test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3518 ; Initialize variable argument processing
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3519 %ap = alloca i8 *
3520 call void %<a href="#i_va_start">llvm.va_start</a>(i8 ** %ap)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3521
3522 ; Read a single integer argument
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3523 %tmp = va_arg i8 ** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3524
3525 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3526 %aq = alloca i8 *
3527 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 ** %aq, i8 ** %ap)
3528 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %aq)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3529
3530 ; Stop processing of arguments.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3531 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %ap)
3532 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3533}
3534</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3535</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3536
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3537<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3538<div class="doc_subsubsection">
3539 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3540</div>
3541
3542
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3543<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3544<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3545<pre> declare void %llvm.va_start(&lt;va_list&gt;* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3546<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3547<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3548<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3549href="#i_va_arg">va_arg</a></tt>.</p>
3550
3551<h5>Arguments:</h5>
3552
3553<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3554
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3555<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3556
3557<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3558macro available in C. In a target-dependent way, it initializes the
3559<tt>va_list</tt> element the argument points to, so that the next call to
3560<tt>va_arg</tt> will produce the first variable argument passed to the function.
3561Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3562last argument of the function, the compiler can figure that out.</p>
3563
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3564</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3565
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3566<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3567<div class="doc_subsubsection">
3568 <a name="i_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3569</div>
3570
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3571<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3572<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3573<pre> declare void %llvm.va_end(&lt;va_list*&gt; &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3574<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3575<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3576which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3577or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3578<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3579<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3580<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3581<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3582macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3583Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3584 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3585with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3586</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3587
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3588<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3589<div class="doc_subsubsection">
3590 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3591</div>
3592
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3593<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3594
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3595<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3596
3597<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3598 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]3599 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3600</pre>
3601
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3602<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3603
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3604<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3605the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3606
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3607<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3608
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3609<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]3610The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3611
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3612
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3613<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3614
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3615<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3616available in C. In a target-dependent way, it copies the source
3617<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3618because the <tt><a href="i_va_begin">llvm.va_begin</a></tt> intrinsic may be
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3619arbitrarily complex and require memory allocation, for example.</p>
3620
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3621</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3622
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3623<!-- ======================================================================= -->
3624<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3625 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3626</div>
3627
3628<div class="doc_text">
3629
3630<p>
3631LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3632Collection</a> requires the implementation and generation of these intrinsics.
3633These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3634stack</a>, as well as garbage collector implementations that require <a
3635href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3636Front-ends for type-safe garbage collected languages should generate these
3637intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3638href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3639</p>
3640</div>
3641
3642<!-- _______________________________________________________________________ -->
3643<div class="doc_subsubsection">
3644 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3645</div>
3646
3647<div class="doc_text">
3648
3649<h5>Syntax:</h5>
3650
3651<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]3652 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3653</pre>
3654
3655<h5>Overview:</h5>
3656
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3657<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3658the code generator, and allows some metadata to be associated with it.</p>
3659
3660<h5>Arguments:</h5>
3661
3662<p>The first argument specifies the address of a stack object that contains the
3663root pointer. The second pointer (which must be either a constant or a global
3664value address) contains the meta-data to be associated with the root.</p>
3665
3666<h5>Semantics:</h5>
3667
3668<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3669location. At compile-time, the code generator generates information to allow
3670the runtime to find the pointer at GC safe points.
3671</p>
3672
3673</div>
3674
3675
3676<!-- _______________________________________________________________________ -->
3677<div class="doc_subsubsection">
3678 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3679</div>
3680
3681<div class="doc_text">
3682
3683<h5>Syntax:</h5>
3684
3685<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3686 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3687</pre>
3688
3689<h5>Overview:</h5>
3690
3691<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3692locations, allowing garbage collector implementations that require read
3693barriers.</p>
3694
3695<h5>Arguments:</h5>
3696
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3697<p>The second argument is the address to read from, which should be an address
3698allocated from the garbage collector. The first object is a pointer to the
3699start of the referenced object, if needed by the language runtime (otherwise
3700null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3701
3702<h5>Semantics:</h5>
3703
3704<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3705instruction, but may be replaced with substantially more complex code by the
3706garbage collector runtime, as needed.</p>
3707
3708</div>
3709
3710
3711<!-- _______________________________________________________________________ -->
3712<div class="doc_subsubsection">
3713 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3714</div>
3715
3716<div class="doc_text">
3717
3718<h5>Syntax:</h5>
3719
3720<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3721 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3722</pre>
3723
3724<h5>Overview:</h5>
3725
3726<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3727locations, allowing garbage collector implementations that require write
3728barriers (such as generational or reference counting collectors).</p>
3729
3730<h5>Arguments:</h5>
3731
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3732<p>The first argument is the reference to store, the second is the start of the
3733object to store it to, and the third is the address of the field of Obj to
3734store to. If the runtime does not require a pointer to the object, Obj may be
3735null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3736
3737<h5>Semantics:</h5>
3738
3739<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3740instruction, but may be replaced with substantially more complex code by the
3741garbage collector runtime, as needed.</p>
3742
3743</div>
3744
3745
3746
3747<!-- ======================================================================= -->
3748<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3749 <a name="int_codegen">Code Generator Intrinsics</a>
3750</div>
3751
3752<div class="doc_text">
3753<p>
3754These intrinsics are provided by LLVM to expose special features that may only
3755be implemented with code generator support.
3756</p>
3757
3758</div>
3759
3760<!-- _______________________________________________________________________ -->
3761<div class="doc_subsubsection">
3762 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3763</div>
3764
3765<div class="doc_text">
3766
3767<h5>Syntax:</h5>
3768<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3769 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3770</pre>
3771
3772<h5>Overview:</h5>
3773
3774<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3775The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3776target-specific value indicating the return address of the current function
3777or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3778</p>
3779
3780<h5>Arguments:</h5>
3781
3782<p>
3783The argument to this intrinsic indicates which function to return the address
3784for. Zero indicates the calling function, one indicates its caller, etc. The
3785argument is <b>required</b> to be a constant integer value.
3786</p>
3787
3788<h5>Semantics:</h5>
3789
3790<p>
3791The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3792the return address of the specified call frame, or zero if it cannot be
3793identified. The value returned by this intrinsic is likely to be incorrect or 0
3794for arguments other than zero, so it should only be used for debugging purposes.
3795</p>
3796
3797<p>
3798Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3799aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3800source-language caller.
3801</p>
3802</div>
3803
3804
3805<!-- _______________________________________________________________________ -->
3806<div class="doc_subsubsection">
3807 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3808</div>
3809
3810<div class="doc_text">
3811
3812<h5>Syntax:</h5>
3813<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3814 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3815</pre>
3816
3817<h5>Overview:</h5>
3818
3819<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3820The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3821target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3822</p>
3823
3824<h5>Arguments:</h5>
3825
3826<p>
3827The argument to this intrinsic indicates which function to return the frame
3828pointer for. Zero indicates the calling function, one indicates its caller,
3829etc. The argument is <b>required</b> to be a constant integer value.
3830</p>
3831
3832<h5>Semantics:</h5>
3833
3834<p>
3835The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3836the frame address of the specified call frame, or zero if it cannot be
3837identified. The value returned by this intrinsic is likely to be incorrect or 0
3838for arguments other than zero, so it should only be used for debugging purposes.
3839</p>
3840
3841<p>
3842Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3843aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3844source-language caller.
3845</p>
3846</div>
3847
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3848<!-- _______________________________________________________________________ -->
3849<div class="doc_subsubsection">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3850 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3851</div>
3852
3853<div class="doc_text">
3854
3855<h5>Syntax:</h5>
3856<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3857 declare i8 *%llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3858</pre>
3859
3860<h5>Overview:</h5>
3861
3862<p>
3863The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3864the function stack, for use with <a href="#i_stackrestore">
3865<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3866features like scoped automatic variable sized arrays in C99.
3867</p>
3868
3869<h5>Semantics:</h5>
3870
3871<p>
3872This intrinsic returns a opaque pointer value that can be passed to <a
3873href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3874<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3875<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3876state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3877practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3878that were allocated after the <tt>llvm.stacksave</tt> was executed.
3879</p>
3880
3881</div>
3882
3883<!-- _______________________________________________________________________ -->
3884<div class="doc_subsubsection">
3885 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3886</div>
3887
3888<div class="doc_text">
3889
3890<h5>Syntax:</h5>
3891<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3892 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3893</pre>
3894
3895<h5>Overview:</h5>
3896
3897<p>
3898The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3899the function stack to the state it was in when the corresponding <a
3900href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3901useful for implementing language features like scoped automatic variable sized
3902arrays in C99.
3903</p>
3904
3905<h5>Semantics:</h5>
3906
3907<p>
3908See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3909</p>
3910
3911</div>
3912
3913
3914<!-- _______________________________________________________________________ -->
3915<div class="doc_subsubsection">
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3916 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3917</div>
3918
3919<div class="doc_text">
3920
3921<h5>Syntax:</h5>
3922<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3923 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3924 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3925</pre>
3926
3927<h5>Overview:</h5>
3928
3929
3930<p>
3931The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3932a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3933no
3934effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]3935characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3936</p>
3937
3938<h5>Arguments:</h5>
3939
3940<p>
3941<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3942determining if the fetch should be for a read (0) or write (1), and
3943<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]3944locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3945<tt>locality</tt> arguments must be constant integers.
3946</p>
3947
3948<h5>Semantics:</h5>
3949
3950<p>
3951This intrinsic does not modify the behavior of the program. In particular,
3952prefetches cannot trap and do not produce a value. On targets that support this
3953intrinsic, the prefetch can provide hints to the processor cache for better
3954performance.
3955</p>
3956
3957</div>
3958
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3959<!-- _______________________________________________________________________ -->
3960<div class="doc_subsubsection">
3961 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3962</div>
3963
3964<div class="doc_text">
3965
3966<h5>Syntax:</h5>
3967<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3968 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3969</pre>
3970
3971<h5>Overview:</h5>
3972
3973
3974<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3975The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3976(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3977code to simulators and other tools. The method is target specific, but it is
3978expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]3979The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]3980after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]3981optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3982correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3983</p>
3984
3985<h5>Arguments:</h5>
3986
3987<p>
3988<tt>id</tt> is a numerical id identifying the marker.
3989</p>
3990
3991<h5>Semantics:</h5>
3992
3993<p>
3994This intrinsic does not modify the behavior of the program. Backends that do not
3995support this intrinisic may ignore it.
3996</p>
3997
3998</div>
3999
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4000<!-- _______________________________________________________________________ -->
4001<div class="doc_subsubsection">
4002 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4003</div>
4004
4005<div class="doc_text">
4006
4007<h5>Syntax:</h5>
4008<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4009 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4010</pre>
4011
4012<h5>Overview:</h5>
4013
4014
4015<p>
4016The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4017counter register (or similar low latency, high accuracy clocks) on those targets
4018that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4019As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4020should only be used for small timings.
4021</p>
4022
4023<h5>Semantics:</h5>
4024
4025<p>
4026When directly supported, reading the cycle counter should not modify any memory.
4027Implementations are allowed to either return a application specific value or a
4028system wide value. On backends without support, this is lowered to a constant 0.
4029</p>
4030
4031</div>
4032
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4033<!-- ======================================================================= -->
4034<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4035 <a name="int_libc">Standard C Library Intrinsics</a>
4036</div>
4037
4038<div class="doc_text">
4039<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4040LLVM provides intrinsics for a few important standard C library functions.
4041These intrinsics allow source-language front-ends to pass information about the
4042alignment of the pointer arguments to the code generator, providing opportunity
4043for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4044</p>
4045
4046</div>
4047
4048<!-- _______________________________________________________________________ -->
4049<div class="doc_subsubsection">
4050 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4051</div>
4052
4053<div class="doc_text">
4054
4055<h5>Syntax:</h5>
4056<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4057 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4058 i32 &lt;len&gt;, i32 &lt;align&gt;)
4059 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4060 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4061</pre>
4062
4063<h5>Overview:</h5>
4064
4065<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4066The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4067location to the destination location.
4068</p>
4069
4070<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4071Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4072intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4073</p>
4074
4075<h5>Arguments:</h5>
4076
4077<p>
4078The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4079the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4080specifying the number of bytes to copy, and the fourth argument is the alignment
4081of the source and destination locations.
4082</p>
4083
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4084<p>
4085If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4086the caller guarantees that both the source and destination pointers are aligned
4087to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4088</p>
4089
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4090<h5>Semantics:</h5>
4091
4092<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4093The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4094location to the destination location, which are not allowed to overlap. It
4095copies "len" bytes of memory over. If the argument is known to be aligned to
4096some boundary, this can be specified as the fourth argument, otherwise it should
4097be set to 0 or 1.
4098</p>
4099</div>
4100
4101
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4102<!-- _______________________________________________________________________ -->
4103<div class="doc_subsubsection">
4104 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4105</div>
4106
4107<div class="doc_text">
4108
4109<h5>Syntax:</h5>
4110<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4111 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4112 i32 &lt;len&gt;, i32 &lt;align&gt;)
4113 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4114 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4115</pre>
4116
4117<h5>Overview:</h5>
4118
4119<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4120The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4121location to the destination location. It is similar to the
4122'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4123</p>
4124
4125<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4126Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4127intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4128</p>
4129
4130<h5>Arguments:</h5>
4131
4132<p>
4133The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4134the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4135specifying the number of bytes to copy, and the fourth argument is the alignment
4136of the source and destination locations.
4137</p>
4138
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4139<p>
4140If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4141the caller guarantees that the source and destination pointers are aligned to
4142that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4143</p>
4144
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4145<h5>Semantics:</h5>
4146
4147<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4148The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4149location to the destination location, which may overlap. It
4150copies "len" bytes of memory over. If the argument is known to be aligned to
4151some boundary, this can be specified as the fourth argument, otherwise it should
4152be set to 0 or 1.
4153</p>
4154</div>
4155
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4156
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4157<!-- _______________________________________________________________________ -->
4158<div class="doc_subsubsection">
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4159 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4160</div>
4161
4162<div class="doc_text">
4163
4164<h5>Syntax:</h5>
4165<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4166 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4167 i32 &lt;len&gt;, i32 &lt;align&gt;)
4168 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4169 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4170</pre>
4171
4172<h5>Overview:</h5>
4173
4174<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4175The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4176byte value.
4177</p>
4178
4179<p>
4180Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4181does not return a value, and takes an extra alignment argument.
4182</p>
4183
4184<h5>Arguments:</h5>
4185
4186<p>
4187The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4188byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4189argument specifying the number of bytes to fill, and the fourth argument is the
4190known alignment of destination location.
4191</p>
4192
4193<p>
4194If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +0000[diff] [blame]4195the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4196</p>
4197
4198<h5>Semantics:</h5>
4199
4200<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4201The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4202the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4203destination location. If the argument is known to be aligned to some boundary,
4204this can be specified as the fourth argument, otherwise it should be set to 0 or
42051.
4206</p>
4207</div>
4208
4209
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4210<!-- _______________________________________________________________________ -->
4211<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4212 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4213</div>
4214
4215<div class="doc_text">
4216
4217<h5>Syntax:</h5>
4218<pre>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4219 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4220 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4221</pre>
4222
4223<h5>Overview:</h5>
4224
4225<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4226The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4227specified floating point values is a NAN.
4228</p>
4229
4230<h5>Arguments:</h5>
4231
4232<p>
4233The arguments are floating point numbers of the same type.
4234</p>
4235
4236<h5>Semantics:</h5>
4237
4238<p>
4239If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4240false.
4241</p>
4242</div>
4243
4244
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4245<!-- _______________________________________________________________________ -->
4246<div class="doc_subsubsection">
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4247 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4248</div>
4249
4250<div class="doc_text">
4251
4252<h5>Syntax:</h5>
4253<pre>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4254 declare float %llvm.sqrt.f32(float %Val)
4255 declare double %llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4256</pre>
4257
4258<h5>Overview:</h5>
4259
4260<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4261The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4262returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4263<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4264negative numbers (which allows for better optimization).
4265</p>
4266
4267<h5>Arguments:</h5>
4268
4269<p>
4270The argument and return value are floating point numbers of the same type.
4271</p>
4272
4273<h5>Semantics:</h5>
4274
4275<p>
4276This function returns the sqrt of the specified operand if it is a positive
4277floating point number.
4278</p>
4279</div>
4280
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4281<!-- _______________________________________________________________________ -->
4282<div class="doc_subsubsection">
4283 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4284</div>
4285
4286<div class="doc_text">
4287
4288<h5>Syntax:</h5>
4289<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4290 declare float %llvm.powi.f32(float %Val, i32 %power)
4291 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4292</pre>
4293
4294<h5>Overview:</h5>
4295
4296<p>
4297The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4298specified (positive or negative) power. The order of evaluation of
4299multiplications is not defined.
4300</p>
4301
4302<h5>Arguments:</h5>
4303
4304<p>
4305The second argument is an integer power, and the first is a value to raise to
4306that power.
4307</p>
4308
4309<h5>Semantics:</h5>
4310
4311<p>
4312This function returns the first value raised to the second power with an
4313unspecified sequence of rounding operations.</p>
4314</div>
4315
4316
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4317<!-- ======================================================================= -->
4318<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4319 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4320</div>
4321
4322<div class="doc_text">
4323<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4324LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4325These allow efficient code generation for some algorithms.
4326</p>
4327
4328</div>
4329
4330<!-- _______________________________________________________________________ -->
4331<div class="doc_subsubsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4332 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4333</div>
4334
4335<div class="doc_text">
4336
4337<h5>Syntax:</h5>
4338<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4339 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4340 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4341 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4342</pre>
4343
4344<h5>Overview:</h5>
4345
4346<p>
4347The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
434864 bit quantity. These are useful for performing operations on data that is not
4349in the target's native byte order.
4350</p>
4351
4352<h5>Semantics:</h5>
4353
4354<p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4355The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4356and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4357intrinsic returns an i32 value that has the four bytes of the input i32
4358swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4359i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4360intrinsic extends this concept to 64 bits.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4361</p>
4362
4363</div>
4364
4365<!-- _______________________________________________________________________ -->
4366<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4367 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4368</div>
4369
4370<div class="doc_text">
4371
4372<h5>Syntax:</h5>
4373<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4374 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4375 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4376 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4377 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4378</pre>
4379
4380<h5>Overview:</h5>
4381
4382<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4383The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4384value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4385</p>
4386
4387<h5>Arguments:</h5>
4388
4389<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4390The only argument is the value to be counted. The argument may be of any
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4391unsigned integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4392</p>
4393
4394<h5>Semantics:</h5>
4395
4396<p>
4397The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4398</p>
4399</div>
4400
4401<!-- _______________________________________________________________________ -->
4402<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4403 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4404</div>
4405
4406<div class="doc_text">
4407
4408<h5>Syntax:</h5>
4409<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4410 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4411 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4412 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4413 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4414</pre>
4415
4416<h5>Overview:</h5>
4417
4418<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4419The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4420leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4421</p>
4422
4423<h5>Arguments:</h5>
4424
4425<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4426The only argument is the value to be counted. The argument may be of any
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4427unsigned integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4428</p>
4429
4430<h5>Semantics:</h5>
4431
4432<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4433The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4434in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4435of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4436</p>
4437</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4438
4439
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4440
4441<!-- _______________________________________________________________________ -->
4442<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4443 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4444</div>
4445
4446<div class="doc_text">
4447
4448<h5>Syntax:</h5>
4449<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4450 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4451 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4452 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4453 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4454</pre>
4455
4456<h5>Overview:</h5>
4457
4458<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4459The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4460trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4461</p>
4462
4463<h5>Arguments:</h5>
4464
4465<p>
4466The only argument is the value to be counted. The argument may be of any
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4467unsigned integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4468</p>
4469
4470<h5>Semantics:</h5>
4471
4472<p>
4473The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4474in a variable. If the src == 0 then the result is the size in bits of the type
4475of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4476</p>
4477</div>
4478
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4479<!-- ======================================================================= -->
4480<div class="doc_subsection">
4481 <a name="int_debugger">Debugger Intrinsics</a>
4482</div>
4483
4484<div class="doc_text">
4485<p>
4486The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4487are described in the <a
4488href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4489Debugging</a> document.
4490</p>
4491</div>
4492
4493
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4494<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4495<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4496<address>
4497 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4498 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4499 <a href="http://validator.w3.org/check/referer"><img
4500 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4501
4502 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]4503 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4504 Last modified: $Date$
4505</address>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4506</body>
4507</html>