Gitiles
Code Review Sign In
gerrit-public.fairphone.software / toolchain / llvm-project / b5ebf3d667e4b248176a9e7e1ffcbdcb739e27e5 / . / llvm / docs / LangRef.html
blob: f87af54978d64d31ff0a1522dea0552f29438f4b [file] [log] [blame]
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
2 "http://www.w3.org/TR/html4/strict.dtd">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3<html>
4<head>
5 <title>LLVM Assembly Language Reference Manual</title>
Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]6 <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]10 <link rel="stylesheet" href="llvm.css" type="text/css">
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 Spencerc329a4e2006-12-28 16:55:55 +0000[diff] [blame]523 prototype and implemented declaration of the function (as does normal C). For
524 integer arguments less than 32-bits, the value will be sign-extended to
525 32-bits before the call is made. If zero-extension is required, use the
526 <tt>cextcc</tt> calling convention.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]527 </dd>
528
Reid Spencerc329a4e2006-12-28 16:55:55 +0000[diff] [blame]529 <dt><b>"<tt>cextcc(bitmask)</tt>" - The C with explicit extend calling
530 convention </b>:</dt>
531 <dd>This calling convention is exactly like the C calling convention except
532 that it is parameterized to provide a <tt>bitmask</tt> that indicates how
533 integer arguments of less than 32-bits should be extended. A zero bit
534 indicates zero-extension while a 1-bit indicates sign-extension. The least
535 significant bit always corresponds to the return type of the function. The
536 bits in the <tt>bitmask</tt> are assigned to the integer parameters of the
537 function that are smaller than 32-bits. For example, a bitmask of value
538 5 (0b0101) indicates that the return value is to be sign extended, the first
539 small integer argument is to be zero extended and the second small integer
540 argument is to be sign extended.</dd>
541
542
Chris Lattner95ff1952006-05-19 21:15:36 +0000[diff] [blame]543 <dt><b>"<tt>csretcc</tt>" - The C struct return calling convention</b>:</dt>
544
545 <dd>This calling convention matches the target C calling conventions, except
546 that functions with this convention are required to take a pointer as their
547 first argument, and the return type of the function must be void. This is
548 used for C functions that return aggregates by-value. In this case, the
549 function has been transformed to take a pointer to the struct as the first
550 argument to the function. For targets where the ABI specifies specific
551 behavior for structure-return calls, the calling convention can be used to
552 distinguish between struct return functions and other functions that take a
553 pointer to a struct as the first argument.
554 </dd>
555
Reid Spencerc329a4e2006-12-28 16:55:55 +0000[diff] [blame]556 <dt><b>"<tt>csretextcc(bitmask)</tt>" - The C struct return with explicit
557 extend calling convention</b>:</dt>
558 <dd>This calling convention is exactly like the <tt>csret</tt> calling
559 convention except that it is parameterized to provide a <tt>bitmask</tt>
560 that indicates how integer arguments of less than 32-bits should be extended.
561 A zero bit indicates zero-extension while a 1-bit indicates sign-extension.
562 </dd>
563
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]564 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
565
566 <dd>This calling convention attempts to make calls as fast as possible
567 (e.g. by passing things in registers). This calling convention allows the
568 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]569 without having to conform to an externally specified ABI. Implementations of
570 this convention should allow arbitrary tail call optimization to be supported.
571 This calling convention does not support varargs and requires the prototype of
572 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]573 </dd>
574
575 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
576
577 <dd>This calling convention attempts to make code in the caller as efficient
578 as possible under the assumption that the call is not commonly executed. As
579 such, these calls often preserve all registers so that the call does not break
580 any live ranges in the caller side. This calling convention does not support
581 varargs and requires the prototype of all callees to exactly match the
582 prototype of the function definition.
583 </dd>
584
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]585 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]586
587 <dd>Any calling convention may be specified by number, allowing
588 target-specific calling conventions to be used. Target specific calling
589 conventions start at 64.
590 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]591</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]592
593<p>More calling conventions can be added/defined on an as-needed basis, to
594support pascal conventions or any other well-known target-independent
595convention.</p>
596
597</div>
598
599<!-- ======================================================================= -->
600<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]601 <a name="globalvars">Global Variables</a>
602</div>
603
604<div class="doc_text">
605
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]606<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]607instead of run-time. Global variables may optionally be initialized, may have
608an explicit section to be placed in, and may
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]609have an optional explicit alignment specified. A
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]610variable may be defined as a global "constant," which indicates that the
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]611contents of the variable will <b>never</b> be modified (enabling better
612optimization, allowing the global data to be placed in the read-only section of
613an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]614cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]615
616<p>
617LLVM explicitly allows <em>declarations</em> of global variables to be marked
618constant, even if the final definition of the global is not. This capability
619can be used to enable slightly better optimization of the program, but requires
620the language definition to guarantee that optimizations based on the
621'constantness' are valid for the translation units that do not include the
622definition.
623</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]624
625<p>As SSA values, global variables define pointer values that are in
626scope (i.e. they dominate) all basic blocks in the program. Global
627variables always define a pointer to their "content" type because they
628describe a region of memory, and all memory objects in LLVM are
629accessed through pointers.</p>
630
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]631<p>LLVM allows an explicit section to be specified for globals. If the target
632supports it, it will emit globals to the section specified.</p>
633
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]634<p>An explicit alignment may be specified for a global. If not present, or if
635the alignment is set to zero, the alignment of the global is set by the target
636to whatever it feels convenient. If an explicit alignment is specified, the
637global is forced to have at least that much alignment. All alignments must be
638a power of 2.</p>
639
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]640</div>
641
642
643<!-- ======================================================================= -->
644<div class="doc_subsection">
645 <a name="functionstructure">Functions</a>
646</div>
647
648<div class="doc_text">
649
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]650<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
651an optional <a href="#linkage">linkage type</a>, an optional
652<a href="#callingconv">calling convention</a>, a return type, an optional
653<a href="#paramattrs">parameter attribute</a> for the return type, a function
654name, a (possibly empty) argument list (each with optional
655<a href="#paramattrs">parameter attributes</a>, an optional section, an optional
656alignment, an opening curly brace, a list of basic blocks, and a closing curly
657brace. LLVM function declarations
658are consist of the "<tt>declare</tt>" keyword, an optional <a
659 href="#callingconv">calling convention</a>, a return type, an optional
660<a href="#paramattrs">parameter attribute</a> for the return type, a function
661name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]662
663<p>A function definition contains a list of basic blocks, forming the CFG for
664the function. Each basic block may optionally start with a label (giving the
665basic block a symbol table entry), contains a list of instructions, and ends
666with a <a href="#terminators">terminator</a> instruction (such as a branch or
667function return).</p>
668
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]669<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]670executed on entrance to the function, and it is not allowed to have predecessor
671basic blocks (i.e. there can not be any branches to the entry block of a
672function). Because the block can have no predecessors, it also cannot have any
673<a href="#i_phi">PHI nodes</a>.</p>
674
675<p>LLVM functions are identified by their name and type signature. Hence, two
676functions with the same name but different parameter lists or return values are
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]677considered different functions, and LLVM will resolve references to each
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]678appropriately.</p>
679
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]680<p>LLVM allows an explicit section to be specified for functions. If the target
681supports it, it will emit functions to the section specified.</p>
682
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]683<p>An explicit alignment may be specified for a function. If not present, or if
684the alignment is set to zero, the alignment of the function is set by the target
685to whatever it feels convenient. If an explicit alignment is specified, the
686function is forced to have at least that much alignment. All alignments must be
687a power of 2.</p>
688
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]689</div>
690
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]691<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]692<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
693<div class="doc_text">
694 <p>The return type and each parameter of a function type may have a set of
695 <i>parameter attributes</i> associated with them. Parameter attributes are
696 used to communicate additional information about the result or parameters of
697 a function. Parameter attributes are considered to be part of the function
698 type so two functions types that differ only by the parameter attributes
699 are different function types.</p>
700
701 <p>Parameter attributes consist of a at sign (@) followed by either a single
702 keyword or a comma separate list of keywords enclosed in parentheses. For
703 example:<pre>
704 %someFunc = i16 @zext (i8 @(sext) %someParam)
705 %someFunc = i16 @zext (i8 @zext %someParam)
706 </pre>Note that the two function types above are unique because the parameter
707 has a different attribute (@sext in the first one, @zext in the second).</p>
708
709 <p>Currently, only the following parameter attributes are defined:
710 <dl>
711 <dt><tt>@zext</tt></dt>
712 <dd>This indicates that the parameter should be zero extended just before
713 a call to this function.</dd>
714 <dt><tt>@sext</tt></dt>
715 <dd>This indicates that the parameter should be sign extended just before
716 a call to this function.</dd>
717 </dl></p>
718
719 <p>The current motivation for parameter attributes is to enable the sign and
720 zero extend information necessary for the C calling convention to be passed
721 from the front end to LLVM. The <tt>@zext</tt> and <tt>@sext</tt> attributes
722 are used by the code generator to perform the required extension. However,
723 parameter attributes are an orthogonal feature to calling conventions and
724 may be used for other purposes in the future.</p>
725</div>
726
727<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]728<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]729 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]730</div>
731
732<div class="doc_text">
733<p>
734Modules may contain "module-level inline asm" blocks, which corresponds to the
735GCC "file scope inline asm" blocks. These blocks are internally concatenated by
736LLVM and treated as a single unit, but may be separated in the .ll file if
737desired. The syntax is very simple:
738</p>
739
740<div class="doc_code"><pre>
Chris Lattnera1280ad2006-01-24 00:37:20 +0000[diff] [blame]741 module asm "inline asm code goes here"
742 module asm "more can go here"
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]743</pre></div>
744
745<p>The strings can contain any character by escaping non-printable characters.
746 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
747 for the number.
748</p>
749
750<p>
751 The inline asm code is simply printed to the machine code .s file when
752 assembly code is generated.
753</p>
754</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]755
756
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]757<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]758<div class="doc_section"> <a name="typesystem">Type System</a> </div>
759<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]760
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]761<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]762
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]763<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]764intermediate representation. Being typed enables a number of
765optimizations to be performed on the IR directly, without having to do
766extra analyses on the side before the transformation. A strong type
767system makes it easier to read the generated code and enables novel
768analyses and transformations that are not feasible to perform on normal
769three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]770
771</div>
772
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]773<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]774<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]775<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]776<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]777system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]778
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]779<table class="layout">
780 <tr class="layout">
781 <td class="left">
782 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]783 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]784 <tr><th>Type</th><th>Description</th></tr>
785 <tr><td><tt>void</tt></td><td>No value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]786 <tr><td><tt>i8</tt></td><td>Signless 8-bit value</td></tr>
787 <tr><td><tt>i32</tt></td><td>Signless 32-bit value</td></tr>
Misha Brukman36c6bc12005-04-22 18:02:52 +0000[diff] [blame]788 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]789 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]790 </tbody>
791 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]792 </td>
793 <td class="right">
794 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]795 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]796 <tr><th>Type</th><th>Description</th></tr>
797 <tr><td><tt>bool</tt></td><td>True or False value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]798 <tr><td><tt>i16</tt></td><td>Signless 16-bit value</td></tr>
799 <tr><td><tt>i64</tt></td><td>Signless 64-bit value</td></tr>
800 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]801 </tbody>
802 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]803 </td>
804 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]805</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]806</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]807
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]808<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]809<div class="doc_subsubsection"> <a name="t_classifications">Type
810Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]811<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]812<p>These different primitive types fall into a few useful
813classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]814
815<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]816 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]817 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]818 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]819 <td><a name="t_integer">integer</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]820 <td><tt>i8, i16, i32, i64</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]821 </tr>
822 <tr>
823 <td><a name="t_integral">integral</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]824 <td><tt>bool, i8, i16, i32, i64</tt>
Misha Brukman20f9a622004-08-12 20:16:08 +0000[diff] [blame]825 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]826 </tr>
827 <tr>
828 <td><a name="t_floating">floating point</a></td>
829 <td><tt>float, double</tt></td>
830 </tr>
831 <tr>
832 <td><a name="t_firstclass">first class</a></td>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]833 <td><tt>bool, i8, i16, i32, i64, float, double, <br/>
834 <a href="#t_pointer">pointer</a>,<a href="#t_packed">packed</a></tt>
835 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]836 </tr>
837 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]838</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]839
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]840<p>The <a href="#t_firstclass">first class</a> types are perhaps the
841most important. Values of these types are the only ones which can be
842produced by instructions, passed as arguments, or used as operands to
843instructions. This means that all structures and arrays must be
844manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]845</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]846
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]847<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]848<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]849
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]850<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]851
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]852<p>The real power in LLVM comes from the derived types in the system.
853This is what allows a programmer to represent arrays, functions,
854pointers, and other useful types. Note that these derived types may be
855recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]856
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]857</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]858
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]859<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]860<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]861
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]862<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]863
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]864<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]865
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]866<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]867sequentially in memory. The array type requires a size (number of
868elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]869
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]870<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]871
872<pre>
873 [&lt;# elements&gt; x &lt;elementtype&gt;]
874</pre>
875
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]876<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]877be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]878
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]879<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]880<table class="layout">
881 <tr class="layout">
882 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]883 <tt>[40 x i32 ]</tt><br/>
884 <tt>[41 x i32 ]</tt><br/>
885 <tt>[40 x i32]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]886 </td>
887 <td class="left">
888 Array of 40 integer values.<br/>
889 Array of 41 integer values.<br/>
890 Array of 40 unsigned integer values.<br/>
891 </td>
892 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]893</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]894<p>Here are some examples of multidimensional arrays:</p>
895<table class="layout">
896 <tr class="layout">
897 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]898 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]899 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]900 <tt>[2 x [3 x [4 x i32]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]901 </td>
902 <td class="left">
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]903 3x4 array of integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]904 12x10 array of single precision floating point values.<br/>
905 2x3x4 array of unsigned integer values.<br/>
906 </td>
907 </tr>
908</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]909
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]910<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
911length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]912LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
913As a special case, however, zero length arrays are recognized to be variable
914length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]915type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]916
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]917</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]918
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]919<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]920<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]921<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]922<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]923<p>The function type can be thought of as a function signature. It
924consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]925Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]926(which are structures of pointers to functions), for indirect function
927calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]928<p>
929The return type of a function type cannot be an aggregate type.
930</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]931<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]932<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]933<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]934specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]935which indicates that the function takes a variable number of arguments.
936Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]937 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]938<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]939<table class="layout">
940 <tr class="layout">
941 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]942 <tt>i32 (i32)</tt> <br/>
943 <tt>float (i16 @sext, i32 *) *</tt><br/>
944 <tt>i32 (i8*, ...)</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]945 </td>
946 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]947 function taking an <tt>i32</tt>, returning an <tt>i32</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]948 <a href="#t_pointer">Pointer</a> to a function that takes an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]949 <tt>i16</tt> that should be sign extended and a
950 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
951 <tt>float</tt>.<br/>
952 A vararg function that takes at least one <a href="#t_pointer">pointer</a>
953 to <tt>i8 </tt> (signed char in C), which returns an integer. This is
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]954 the signature for <tt>printf</tt> in LLVM.<br/>
955 </td>
956 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]957</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]958
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]959</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]960<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]961<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]962<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]963<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]964<p>The structure type is used to represent a collection of data members
965together in memory. The packing of the field types is defined to match
966the ABI of the underlying processor. The elements of a structure may
967be any type that has a size.</p>
968<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
969and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
970field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
971instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]972<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]973<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]974<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]975<table class="layout">
976 <tr class="layout">
977 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]978 <tt>{ i32, i32, i32 }</tt><br/>
979 <tt>{ float, i32 (i32) * }</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]980 </td>
981 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]982 a triple of three <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]983 A pair, where the first element is a <tt>float</tt> and the second element
984 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^]985 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]986 </td>
987 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]988</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]989</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]990
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]991<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]992<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
993</div>
994<div class="doc_text">
995<h5>Overview:</h5>
996<p>The packed structure type is used to represent a collection of data members
997together in memory. There is no padding between fields. Further, the alignment
998of a packed structure is 1 byte. The elements of a packed structure may
999be any type that has a size.</p>
1000<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1001and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1002field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1003instruction.</p>
1004<h5>Syntax:</h5>
1005<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1006<h5>Examples:</h5>
1007<table class="layout">
1008 <tr class="layout">
1009 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1010 <tt> &lt; { i32, i32, i32 } &gt; </tt><br/>
1011 <tt> &lt; { float, i32 (i32) * } &gt; </tt><br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1012 </td>
1013 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1014 a triple of three <tt>i32</tt> values<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1015 A pair, where the first element is a <tt>float</tt> and the second element
1016 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^]1017 that takes an <tt>i32</tt>, returning an <tt>i32</tt>.<br/>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1018 </td>
1019 </tr>
1020</table>
1021</div>
1022
1023<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1024<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1025<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1026<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1027<p>As in many languages, the pointer type represents a pointer or
1028reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1029<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1030<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1031<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1032<table class="layout">
1033 <tr class="layout">
1034 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1035 <tt>[4x i32]*</tt><br/>
1036 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1037 </td>
1038 <td class="left">
1039 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^]1040 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1041 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1042 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1043 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1044 </td>
1045 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1046</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1047</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1048
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1049<!-- _______________________________________________________________________ -->
1050<div class="doc_subsubsection"> <a name="t_packed">Packed Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1051<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1052
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1053<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1054
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1055<p>A packed type is a simple derived type that represents a vector
1056of elements. Packed types are used when multiple primitive data
1057are operated in parallel using a single instruction (SIMD).
1058A packed type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1059elements) and an underlying primitive data type. Vectors must have a power
1060of two length (1, 2, 4, 8, 16 ...). Packed types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1061considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1062
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1063<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1064
1065<pre>
1066 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1067</pre>
1068
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1069<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1070be any integral or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1071
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1072<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1073
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1074<table class="layout">
1075 <tr class="layout">
1076 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1077 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1078 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1079 <tt>&lt;2 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1080 </td>
1081 <td class="left">
1082 Packed vector of 4 integer values.<br/>
1083 Packed vector of 8 floating-point values.<br/>
1084 Packed vector of 2 unsigned integer values.<br/>
1085 </td>
1086 </tr>
1087</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1088</div>
1089
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1090<!-- _______________________________________________________________________ -->
1091<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1092<div class="doc_text">
1093
1094<h5>Overview:</h5>
1095
1096<p>Opaque types are used to represent unknown types in the system. This
1097corresponds (for example) to the C notion of a foward declared structure type.
1098In LLVM, opaque types can eventually be resolved to any type (not just a
1099structure type).</p>
1100
1101<h5>Syntax:</h5>
1102
1103<pre>
1104 opaque
1105</pre>
1106
1107<h5>Examples:</h5>
1108
1109<table class="layout">
1110 <tr class="layout">
1111 <td class="left">
1112 <tt>opaque</tt>
1113 </td>
1114 <td class="left">
1115 An opaque type.<br/>
1116 </td>
1117 </tr>
1118</table>
1119</div>
1120
1121
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1122<!-- *********************************************************************** -->
1123<div class="doc_section"> <a name="constants">Constants</a> </div>
1124<!-- *********************************************************************** -->
1125
1126<div class="doc_text">
1127
1128<p>LLVM has several different basic types of constants. This section describes
1129them all and their syntax.</p>
1130
1131</div>
1132
1133<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1134<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1135
1136<div class="doc_text">
1137
1138<dl>
1139 <dt><b>Boolean constants</b></dt>
1140
1141 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
1142 constants of the <tt><a href="#t_primitive">bool</a></tt> type.
1143 </dd>
1144
1145 <dt><b>Integer constants</b></dt>
1146
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1147 <dd>Standard integers (such as '4') are constants of the <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1148 href="#t_integer">integer</a> type. Negative numbers may be used with signed
1149 integer types.
1150 </dd>
1151
1152 <dt><b>Floating point constants</b></dt>
1153
1154 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1155 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1156 notation (see below). Floating point constants must have a <a
1157 href="#t_floating">floating point</a> type. </dd>
1158
1159 <dt><b>Null pointer constants</b></dt>
1160
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1161 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1162 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1163
1164</dl>
1165
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1166<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1167of floating point constants. For example, the form '<tt>double
11680x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
11694.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1170(and the only time that they are generated by the disassembler) is when a
1171floating point constant must be emitted but it cannot be represented as a
1172decimal floating point number. For example, NaN's, infinities, and other
1173special values are represented in their IEEE hexadecimal format so that
1174assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1175
1176</div>
1177
1178<!-- ======================================================================= -->
1179<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1180</div>
1181
1182<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1183<p>Aggregate constants arise from aggregation of simple constants
1184and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1185
1186<dl>
1187 <dt><b>Structure constants</b></dt>
1188
1189 <dd>Structure constants are represented with notation similar to structure
1190 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1191 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
1192 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]1193 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1194 types of elements must match those specified by the type.
1195 </dd>
1196
1197 <dt><b>Array constants</b></dt>
1198
1199 <dd>Array constants are represented with notation similar to array type
1200 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1201 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1202 constants must have <a href="#t_array">array type</a>, and the number and
1203 types of elements must match those specified by the type.
1204 </dd>
1205
1206 <dt><b>Packed constants</b></dt>
1207
1208 <dd>Packed constants are represented with notation similar to packed type
1209 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1210 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
1211 i32 11, i32 74, i32 100 &gt;</tt>". Packed constants must have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1212 href="#t_packed">packed type</a>, and the number and types of elements must
1213 match those specified by the type.
1214 </dd>
1215
1216 <dt><b>Zero initialization</b></dt>
1217
1218 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1219 value to zero of <em>any</em> type, including scalar and aggregate types.
1220 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]1221 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1222 initializers.
1223 </dd>
1224</dl>
1225
1226</div>
1227
1228<!-- ======================================================================= -->
1229<div class="doc_subsection">
1230 <a name="globalconstants">Global Variable and Function Addresses</a>
1231</div>
1232
1233<div class="doc_text">
1234
1235<p>The addresses of <a href="#globalvars">global variables</a> and <a
1236href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1237constants. These constants are explicitly referenced when the <a
1238href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1239href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1240file:</p>
1241
1242<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1243 %X = global i32 17
1244 %Y = global i32 42
1245 %Z = global [2 x i32*] [ i32* %X, i32* %Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1246</pre>
1247
1248</div>
1249
1250<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1251<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1252<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1253 <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]1254 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1255 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1256
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1257 <p>Undefined values indicate to the compiler that the program is well defined
1258 no matter what value is used, giving the compiler more freedom to optimize.
1259 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1260</div>
1261
1262<!-- ======================================================================= -->
1263<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1264</div>
1265
1266<div class="doc_text">
1267
1268<p>Constant expressions are used to allow expressions involving other constants
1269to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1270href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1271that does not have side effects (e.g. load and call are not supported). The
1272following is the syntax for constant expressions:</p>
1273
1274<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1275 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1276 <dd>Truncate a constant to another type. The bit size of CST must be larger
1277 than the bit size of TYPE. Both types must be integral.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1278
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1279 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1280 <dd>Zero extend a constant to another type. The bit size of CST must be
1281 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1282
1283 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1284 <dd>Sign extend a constant to another type. The bit size of CST must be
1285 smaller or equal to the bit size of TYPE. Both types must be integral.</dd>
1286
1287 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1288 <dd>Truncate a floating point constant to another floating point type. The
1289 size of CST must be larger than the size of TYPE. Both types must be
1290 floating point.</dd>
1291
1292 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1293 <dd>Floating point extend a constant to another type. The size of CST must be
1294 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1295
1296 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1297 <dd>Convert a floating point constant to the corresponding unsigned integer
1298 constant. TYPE must be an integer type. CST must be floating point. If the
1299 value won't fit in the integer type, the results are undefined.</dd>
1300
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1301 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1302 <dd>Convert a floating point constant to the corresponding signed integer
1303 constant. TYPE must be an integer type. CST must be floating point. If the
1304 value won't fit in the integer type, the results are undefined.</dd>
1305
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1306 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1307 <dd>Convert an unsigned integer constant to the corresponding floating point
1308 constant. TYPE must be floating point. CST must be of integer type. If the
1309 value won't fit in the floating point type, the results are undefined.</dd>
1310
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1311 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1312 <dd>Convert a signed integer constant to the corresponding floating point
1313 constant. TYPE must be floating point. CST must be of integer type. If the
1314 value won't fit in the floating point type, the results are undefined.</dd>
1315
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1316 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1317 <dd>Convert a pointer typed constant to the corresponding integer constant
1318 TYPE must be an integer type. CST must be of pointer type. The CST value is
1319 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1320
1321 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1322 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1323 pointer type. CST must be of integer type. The CST value is zero extended,
1324 truncated, or unchanged to make it fit in a pointer size. This one is
1325 <i>really</i> dangerous!</dd>
1326
1327 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1328 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1329 identical (same number of bits). The conversion is done as if the CST value
1330 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]1331 with this operator, just the type. This can be used for conversion of
1332 packed types to any other type, as long as they have the same bit width. For
1333 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1334 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1335
1336 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1337
1338 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1339 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1340 instruction, the index list may have zero or more indexes, which are required
1341 to make sense for the type of "CSTPTR".</dd>
1342
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1343 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1344
1345 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1346 constants.</dd>
1347
1348 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1349 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1350
1351 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1352 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1353
1354 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1355
1356 <dd>Perform the <a href="#i_extractelement">extractelement
1357 operation</a> on constants.
1358
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1359 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1360
1361 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1362 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1363
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1364
1365 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1366
1367 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1368 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1369
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1370 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1371
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1372 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1373 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1374 binary</a> operations. The constraints on operands are the same as those for
1375 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1376 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1377</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1378</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1379
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1380<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1381<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1382<!-- *********************************************************************** -->
1383
1384<!-- ======================================================================= -->
1385<div class="doc_subsection">
1386<a name="inlineasm">Inline Assembler Expressions</a>
1387</div>
1388
1389<div class="doc_text">
1390
1391<p>
1392LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1393Module-Level Inline Assembly</a>) through the use of a special value. This
1394value represents the inline assembler as a string (containing the instructions
1395to emit), a list of operand constraints (stored as a string), and a flag that
1396indicates whether or not the inline asm expression has side effects. An example
1397inline assembler expression is:
1398</p>
1399
1400<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1401 i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1402</pre>
1403
1404<p>
1405Inline assembler expressions may <b>only</b> be used as the callee operand of
1406a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1407</p>
1408
1409<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1410 %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]1411</pre>
1412
1413<p>
1414Inline asms with side effects not visible in the constraint list must be marked
1415as having side effects. This is done through the use of the
1416'<tt>sideeffect</tt>' keyword, like so:
1417</p>
1418
1419<pre>
1420 call void asm sideeffect "eieio", ""()
1421</pre>
1422
1423<p>TODO: The format of the asm and constraints string still need to be
1424documented here. Constraints on what can be done (e.g. duplication, moving, etc
1425need to be documented).
1426</p>
1427
1428</div>
1429
1430<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1431<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1432<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1433
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1434<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1435
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1436<p>The LLVM instruction set consists of several different
1437classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1438instructions</a>, <a href="#binaryops">binary instructions</a>,
1439<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1440 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1441instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1442
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1443</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1444
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1445<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1446<div class="doc_subsection"> <a name="terminators">Terminator
1447Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1448
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1449<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1450
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1451<p>As mentioned <a href="#functionstructure">previously</a>, every
1452basic block in a program ends with a "Terminator" instruction, which
1453indicates which block should be executed after the current block is
1454finished. These terminator instructions typically yield a '<tt>void</tt>'
1455value: they produce control flow, not values (the one exception being
1456the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1457<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1458 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1459instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1460the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1461 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1462 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1463
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1464</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1465
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1466<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1467<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1468Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1469<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1470<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1471<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]1472 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1473</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1474<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1475<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1476value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1477<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1478returns a value and then causes control flow, and one that just causes
1479control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1480<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1481<p>The '<tt>ret</tt>' instruction may return any '<a
1482 href="#t_firstclass">first class</a>' type. Notice that a function is
1483not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1484instruction inside of the function that returns a value that does not
1485match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1486<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1487<p>When the '<tt>ret</tt>' instruction is executed, control flow
1488returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1489 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1490the instruction after the call. If the caller was an "<a
1491 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1492at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1493returns a value, that value shall set the call or invoke instruction's
1494return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1495<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1496<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1497 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1498</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1499</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1500<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1501<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1502<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1503<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1504<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]1505</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1506<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1507<p>The '<tt>br</tt>' instruction is used to cause control flow to
1508transfer to a different basic block in the current function. There are
1509two forms of this instruction, corresponding to a conditional branch
1510and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1511<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1512<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
1513single '<tt>bool</tt>' value and two '<tt>label</tt>' values. The
1514unconditional form of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>'
1515value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1516<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1517<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>bool</tt>'
1518argument is evaluated. If the value is <tt>true</tt>, control flows
1519to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1520control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1521<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1522<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
1523 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]1524</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1525<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1526<div class="doc_subsubsection">
1527 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1528</div>
1529
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1530<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1531<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1532
1533<pre>
1534 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1535</pre>
1536
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1537<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1538
1539<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1540several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1541instruction, allowing a branch to occur to one of many possible
1542destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1543
1544
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1545<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1546
1547<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1548comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1549an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1550table is not allowed to contain duplicate constant entries.</p>
1551
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1552<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1553
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1554<p>The <tt>switch</tt> instruction specifies a table of values and
1555destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1556table is searched for the given value. If the value is found, control flow is
1557transfered to the corresponding destination; otherwise, control flow is
1558transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1559
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1560<h5>Implementation:</h5>
1561
1562<p>Depending on properties of the target machine and the particular
1563<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1564ways. For example, it could be generated as a series of chained conditional
1565branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1566
1567<h5>Example:</h5>
1568
1569<pre>
1570 <i>; Emulate a conditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1571 %Val = <a href="#i_zext">zext</a> bool %value to i32
1572 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1573
1574 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1575 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1576
1577 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1578 switch i32 %val, label %otherwise [ i32 0, label %onzero
1579 i32 1, label %onone
1580 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1581</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1582</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1583
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1584<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1585<div class="doc_subsubsection">
1586 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1587</div>
1588
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1589<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1590
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1591<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1592
1593<pre>
1594 &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]1595 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1596</pre>
1597
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1598<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1599
1600<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1601function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1602'<tt>normal</tt>' label or the
1603'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1604"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1605"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1606href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1607continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1608
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1609<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1610
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1611<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1612
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1613<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1614 <li>
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1615 The optional "cconv" marker indicates which <a href="callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1616 convention</a> the call should use. If none is specified, the call defaults
1617 to using C calling conventions.
1618 </li>
1619 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1620 function value being invoked. In most cases, this is a direct function
1621 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1622 an arbitrary pointer to function value.
1623 </li>
1624
1625 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1626 function to be invoked. </li>
1627
1628 <li>'<tt>function args</tt>': argument list whose types match the function
1629 signature argument types. If the function signature indicates the function
1630 accepts a variable number of arguments, the extra arguments can be
1631 specified. </li>
1632
1633 <li>'<tt>normal label</tt>': the label reached when the called function
1634 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1635
1636 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1637 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1638
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1639</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1640
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1641<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1643<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1644href="#i_call">call</a></tt>' instruction in most regards. The primary
1645difference is that it establishes an association with a label, which is used by
1646the runtime library to unwind the stack.</p>
1647
1648<p>This instruction is used in languages with destructors to ensure that proper
1649cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1650exception. Additionally, this is important for implementation of
1651'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1652
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1653<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1654<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1655 %retval = invoke i32 %Test(i32 15) to label %Continue
1656 unwind label %TestCleanup <i>; {i32}:retval set</i>
1657 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1658 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1659</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1660</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1661
1662
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1663<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1664
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1665<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1666Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1667
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1668<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1669
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1670<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1671<pre>
1672 unwind
1673</pre>
1674
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1675<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1676
1677<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1678at the first callee in the dynamic call stack which used an <a
1679href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1680primarily used to implement exception handling.</p>
1681
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1682<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1683
1684<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1685immediately halt. The dynamic call stack is then searched for the first <a
1686href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1687execution continues at the "exceptional" destination block specified by the
1688<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1689dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1690</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1691
1692<!-- _______________________________________________________________________ -->
1693
1694<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1695Instruction</a> </div>
1696
1697<div class="doc_text">
1698
1699<h5>Syntax:</h5>
1700<pre>
1701 unreachable
1702</pre>
1703
1704<h5>Overview:</h5>
1705
1706<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1707instruction is used to inform the optimizer that a particular portion of the
1708code is not reachable. This can be used to indicate that the code after a
1709no-return function cannot be reached, and other facts.</p>
1710
1711<h5>Semantics:</h5>
1712
1713<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1714</div>
1715
1716
1717
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1718<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1719<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1720<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1721<p>Binary operators are used to do most of the computation in a
1722program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1723produce a single value. The operands might represent
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1724multiple data, as is the case with the <a href="#t_packed">packed</a> data type.
1725The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1726necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1727<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1728</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1729<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1730<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1731Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1732<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1733<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1734<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]1735</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1736<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1737<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1738<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1739<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1740 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
1741 This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1742Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1743<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1744<p>The value produced is the integer or floating point sum of the two
1745operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1746<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1747<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]1748</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1749</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1750<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1751<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1752Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1753<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1754<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1755<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]1756</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1757<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1758<p>The '<tt>sub</tt>' instruction returns the difference of its two
1759operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1760<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1761instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1762<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1763<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1764 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1765values.
1766This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1767Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1768<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1769<p>The value produced is the integer or floating point difference of
1770the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1771<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1772<pre> &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
1773 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1774</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1775</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1776<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1777<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1778Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1779<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1780<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1781<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]1782</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1783<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1784<p>The '<tt>mul</tt>' instruction returns the product of its two
1785operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1786<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1787<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1788 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1789values.
1790This instruction can also take <a href="#t_packed">packed</a> versions of the values.
1791Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1792<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1793<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1794two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1795<p>There is no signed vs unsigned multiplication. The appropriate
1796action is taken based on the type of the operand.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1797<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1798<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]1799</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1800</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1801<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1802<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
1803</a></div>
1804<div class="doc_text">
1805<h5>Syntax:</h5>
1806<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1807</pre>
1808<h5>Overview:</h5>
1809<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
1810operands.</p>
1811<h5>Arguments:</h5>
1812<p>The two arguments to the '<tt>udiv</tt>' instruction must be
1813<a href="#t_integer">integer</a> values. Both arguments must have identical
1814types. This instruction can also take <a href="#t_packed">packed</a> versions
1815of the values in which case the elements must be integers.</p>
1816<h5>Semantics:</h5>
1817<p>The value produced is the unsigned integer quotient of the two operands. This
1818instruction always performs an unsigned division operation, regardless of
1819whether the arguments are unsigned or not.</p>
1820<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1821<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]1822</pre>
1823</div>
1824<!-- _______________________________________________________________________ -->
1825<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
1826</a> </div>
1827<div class="doc_text">
1828<h5>Syntax:</h5>
1829<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1830</pre>
1831<h5>Overview:</h5>
1832<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
1833operands.</p>
1834<h5>Arguments:</h5>
1835<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
1836<a href="#t_integer">integer</a> values. Both arguments must have identical
1837types. This instruction can also take <a href="#t_packed">packed</a> versions
1838of the values in which case the elements must be integers.</p>
1839<h5>Semantics:</h5>
1840<p>The value produced is the signed integer quotient of the two operands. This
1841instruction always performs a signed division operation, regardless of whether
1842the arguments are signed or not.</p>
1843<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1844<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]1845</pre>
1846</div>
1847<!-- _______________________________________________________________________ -->
1848<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1849Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1850<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1851<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1852<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]1853</pre>
1854<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1855<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1856operands.</p>
1857<h5>Arguments:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1858<p>The two arguments to the '<tt>div</tt>' instruction must be
1859<a href="#t_floating">floating point</a> values. Both arguments must have
1860identical types. This instruction can also take <a href="#t_packed">packed</a>
1861versions of the values in which case the elements must be floating point.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1862<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1863<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1864<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]1865<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]1866</pre>
1867</div>
1868<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1869<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
1870</div>
1871<div class="doc_text">
1872<h5>Syntax:</h5>
1873<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1874</pre>
1875<h5>Overview:</h5>
1876<p>The '<tt>urem</tt>' instruction returns the remainder from the
1877unsigned division of its two arguments.</p>
1878<h5>Arguments:</h5>
1879<p>The two arguments to the '<tt>urem</tt>' instruction must be
1880<a href="#t_integer">integer</a> values. Both arguments must have identical
1881types.</p>
1882<h5>Semantics:</h5>
1883<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
1884This instruction always performs an unsigned division to get the remainder,
1885regardless of whether the arguments are unsigned or not.</p>
1886<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1887<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]1888</pre>
1889
1890</div>
1891<!-- _______________________________________________________________________ -->
1892<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1893Instruction</a> </div>
1894<div class="doc_text">
1895<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1896<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]1897</pre>
1898<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1899<p>The '<tt>srem</tt>' instruction returns the remainder from the
1900signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1901<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1902<p>The two arguments to the '<tt>srem</tt>' instruction must be
1903<a href="#t_integer">integer</a> values. Both arguments must have identical
1904types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1905<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]1906<p>This instruction returns the <i>remainder</i> of a division (where the result
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1907has the same sign as the divisor), not the <i>modulus</i> (where the
1908result has the same sign as the dividend) of a value. For more
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1909information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1910 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
1911Math Forum</a>.</p>
1912<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1913<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]1914</pre>
1915
1916</div>
1917<!-- _______________________________________________________________________ -->
1918<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
1919Instruction</a> </div>
1920<div class="doc_text">
1921<h5>Syntax:</h5>
1922<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
1923</pre>
1924<h5>Overview:</h5>
1925<p>The '<tt>frem</tt>' instruction returns the remainder from the
1926division of its two operands.</p>
1927<h5>Arguments:</h5>
1928<p>The two arguments to the '<tt>frem</tt>' instruction must be
1929<a href="#t_floating">floating point</a> values. Both arguments must have
1930identical types.</p>
1931<h5>Semantics:</h5>
1932<p>This instruction returns the <i>remainder</i> of a division.</p>
1933<h5>Example:</h5>
1934<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]1935</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1936</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]1937
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1938<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1939<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
1940Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1941<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1942<p>Bitwise binary operators are used to do various forms of
1943bit-twiddling in a program. They are generally very efficient
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1944instructions and can commonly be strength reduced from other
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1945instructions. They require two operands, execute an operation on them,
1946and produce a single value. The resulting value of the bitwise binary
1947operators is always the same type as its first operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1948</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1949<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1950<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
1951Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1952<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1953<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1954<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]1955</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1956<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1957<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
1958its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1959<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1960<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1961 href="#t_integral">integral</a> values. Both arguments must have
1962identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1963<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1964<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1965<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1966<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1967<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1968 <tbody>
1969 <tr>
1970 <td>In0</td>
1971 <td>In1</td>
1972 <td>Out</td>
1973 </tr>
1974 <tr>
1975 <td>0</td>
1976 <td>0</td>
1977 <td>0</td>
1978 </tr>
1979 <tr>
1980 <td>0</td>
1981 <td>1</td>
1982 <td>0</td>
1983 </tr>
1984 <tr>
1985 <td>1</td>
1986 <td>0</td>
1987 <td>0</td>
1988 </tr>
1989 <tr>
1990 <td>1</td>
1991 <td>1</td>
1992 <td>1</td>
1993 </tr>
1994 </tbody>
1995</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1996</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1997<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]1998<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
1999 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2000 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2001</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2002</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2003<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2004<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2005<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2006<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2007<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]2008</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2009<h5>Overview:</h5>
2010<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2011or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2012<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2013<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2014 href="#t_integral">integral</a> values. Both arguments must have
2015identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2016<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2017<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2018<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2019<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2020<table border="1" cellspacing="0" cellpadding="4">
2021 <tbody>
2022 <tr>
2023 <td>In0</td>
2024 <td>In1</td>
2025 <td>Out</td>
2026 </tr>
2027 <tr>
2028 <td>0</td>
2029 <td>0</td>
2030 <td>0</td>
2031 </tr>
2032 <tr>
2033 <td>0</td>
2034 <td>1</td>
2035 <td>1</td>
2036 </tr>
2037 <tr>
2038 <td>1</td>
2039 <td>0</td>
2040 <td>1</td>
2041 </tr>
2042 <tr>
2043 <td>1</td>
2044 <td>1</td>
2045 <td>1</td>
2046 </tr>
2047 </tbody>
2048</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2049</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2050<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2051<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2052 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2053 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2054</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2055</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2056<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2057<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2058Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2059<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2060<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2061<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]2062</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2063<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2064<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2065or of its two operands. The <tt>xor</tt> is used to implement the
2066"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2067<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2068<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2069 href="#t_integral">integral</a> values. Both arguments must have
2070identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2071<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2072<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2073<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2074<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2075<table border="1" cellspacing="0" cellpadding="4">
2076 <tbody>
2077 <tr>
2078 <td>In0</td>
2079 <td>In1</td>
2080 <td>Out</td>
2081 </tr>
2082 <tr>
2083 <td>0</td>
2084 <td>0</td>
2085 <td>0</td>
2086 </tr>
2087 <tr>
2088 <td>0</td>
2089 <td>1</td>
2090 <td>1</td>
2091 </tr>
2092 <tr>
2093 <td>1</td>
2094 <td>0</td>
2095 <td>1</td>
2096 </tr>
2097 <tr>
2098 <td>1</td>
2099 <td>1</td>
2100 <td>0</td>
2101 </tr>
2102 </tbody>
2103</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2104</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2105<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2106<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2107<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2108 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2109 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2110 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</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<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2114<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
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; = 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]2119</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2120<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2121<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2122the left a specified number of bits.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2123<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2124<p>The first argument to the '<tt>shl</tt>' instruction must be an <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2125 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]2126type.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2127<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2128<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]2129<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2130<pre> &lt;result&gt; = shl i32 4, i8 %var <i>; yields {i32}:result = 4 &lt;&lt; %var</i>
2131 &lt;result&gt; = shl i32 4, i8 2 <i>; yields {i32}:result = 16</i>
2132 &lt;result&gt; = shl i32 1, i8 10 <i>; yields {i32}:result = 1024</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2133</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2134</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2135<!-- _______________________________________________________________________ -->
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2136<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2137Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2138<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2139<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2140<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]2141</pre>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2142
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2143<h5>Overview:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2144<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
2145operand shifted to the right a specified number of bits.</p>
2146
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2147<h5>Arguments:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2148<p>The first argument to the '<tt>lshr</tt>' instruction must be an <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2149 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]2150
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2151<h5>Semantics:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2152<p>This instruction always performs a logical shift right operation, regardless
2153of whether the arguments are unsigned or not. The <tt>var2</tt> most significant
2154bits will be filled with zero bits after the shift.</p>
2155
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2156<h5>Example:</h5>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2157<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2158 &lt;result&gt; = lshr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2159 &lt;result&gt; = lshr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2160 &lt;result&gt; = lshr i8 4, i8 3 <i>; yields {i8 }:result = 0</i>
2161 &lt;result&gt; = lshr i8 -2, i8 1 <i>; yields {i8 }:result = 0x7FFFFFFF </i>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2162</pre>
2163</div>
2164
2165<!-- ======================================================================= -->
2166<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2167Instruction</a> </div>
2168<div class="doc_text">
2169
2170<h5>Syntax:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2171<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]2172</pre>
2173
2174<h5>Overview:</h5>
2175<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
2176operand shifted to the right a specified number of bits.</p>
2177
2178<h5>Arguments:</h5>
2179<p>The first argument to the '<tt>ashr</tt>' instruction must be an
2180<a href="#t_integer">integer</a> type. The second argument must be an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2181'<tt>i8</tt>' type.</p>
Reid Spencerfdff9382006-11-08 06:47:33 +0000[diff] [blame]2182
2183<h5>Semantics:</h5>
2184<p>This instruction always performs an arithmetic shift right operation,
2185regardless of whether the arguments are signed or not. The <tt>var2</tt> most
2186significant bits will be filled with the sign bit of <tt>var1</tt>.</p>
2187
2188<h5>Example:</h5>
2189<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2190 &lt;result&gt; = ashr i32 4, i8 1 <i>; yields {i32}:result = 2</i>
2191 &lt;result&gt; = ashr i32 4, i8 2 <i>; yields {i32}:result = 1</i>
2192 &lt;result&gt; = ashr i8 4, i8 3 <i>; yields {i8}:result = 0</i>
2193 &lt;result&gt; = ashr i8 -2, i8 1 <i>; yields {i8 }:result = -1</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2194</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2195</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2196
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2197<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2198<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2199 <a name="vectorops">Vector Operations</a>
2200</div>
2201
2202<div class="doc_text">
2203
2204<p>LLVM supports several instructions to represent vector operations in a
2205target-independent manner. This instructions cover the element-access and
2206vector-specific operations needed to process vectors effectively. While LLVM
2207does directly support these vector operations, many sophisticated algorithms
2208will want to use target-specific intrinsics to take full advantage of a specific
2209target.</p>
2210
2211</div>
2212
2213<!-- _______________________________________________________________________ -->
2214<div class="doc_subsubsection">
2215 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2216</div>
2217
2218<div class="doc_text">
2219
2220<h5>Syntax:</h5>
2221
2222<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2223 &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]2224</pre>
2225
2226<h5>Overview:</h5>
2227
2228<p>
2229The '<tt>extractelement</tt>' instruction extracts a single scalar
2230element from a packed vector at a specified index.
2231</p>
2232
2233
2234<h5>Arguments:</h5>
2235
2236<p>
2237The first operand of an '<tt>extractelement</tt>' instruction is a
2238value of <a href="#t_packed">packed</a> type. The second operand is
2239an index indicating the position from which to extract the element.
2240The index may be a variable.</p>
2241
2242<h5>Semantics:</h5>
2243
2244<p>
2245The result is a scalar of the same type as the element type of
2246<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2247<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2248results are undefined.
2249</p>
2250
2251<h5>Example:</h5>
2252
2253<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2254 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2255</pre>
2256</div>
2257
2258
2259<!-- _______________________________________________________________________ -->
2260<div class="doc_subsubsection">
2261 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2262</div>
2263
2264<div class="doc_text">
2265
2266<h5>Syntax:</h5>
2267
2268<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2269 &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]2270</pre>
2271
2272<h5>Overview:</h5>
2273
2274<p>
2275The '<tt>insertelement</tt>' instruction inserts a scalar
2276element into a packed vector at a specified index.
2277</p>
2278
2279
2280<h5>Arguments:</h5>
2281
2282<p>
2283The first operand of an '<tt>insertelement</tt>' instruction is a
2284value of <a href="#t_packed">packed</a> type. The second operand is a
2285scalar value whose type must equal the element type of the first
2286operand. The third operand is an index indicating the position at
2287which to insert the value. The index may be a variable.</p>
2288
2289<h5>Semantics:</h5>
2290
2291<p>
2292The result is a packed vector of the same type as <tt>val</tt>. Its
2293element values are those of <tt>val</tt> except at position
2294<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2295exceeds the length of <tt>val</tt>, the results are undefined.
2296</p>
2297
2298<h5>Example:</h5>
2299
2300<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2301 %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]2302</pre>
2303</div>
2304
2305<!-- _______________________________________________________________________ -->
2306<div class="doc_subsubsection">
2307 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2308</div>
2309
2310<div class="doc_text">
2311
2312<h5>Syntax:</h5>
2313
2314<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2315 &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]2316</pre>
2317
2318<h5>Overview:</h5>
2319
2320<p>
2321The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2322from two input vectors, returning a vector of the same type.
2323</p>
2324
2325<h5>Arguments:</h5>
2326
2327<p>
2328The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2329with types that match each other and types that match the result of the
2330instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2331of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2332</p>
2333
2334<p>
2335The shuffle mask operand is required to be a constant vector with either
2336constant integer or undef values.
2337</p>
2338
2339<h5>Semantics:</h5>
2340
2341<p>
2342The elements of the two input vectors are numbered from left to right across
2343both of the vectors. The shuffle mask operand specifies, for each element of
2344the result vector, which element of the two input registers the result element
2345gets. The element selector may be undef (meaning "don't care") and the second
2346operand may be undef if performing a shuffle from only one vector.
2347</p>
2348
2349<h5>Example:</h5>
2350
2351<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2352 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
2353 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
2354 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2355 &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]2356</pre>
2357</div>
2358
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2359
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2360<!-- ======================================================================= -->
2361<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2362 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2363</div>
2364
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2365<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2366
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2367<p>A key design point of an SSA-based representation is how it
2368represents memory. In LLVM, no memory locations are in SSA form, which
2369makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2370allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2371
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2372</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2373
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2374<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2375<div class="doc_subsubsection">
2376 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2377</div>
2378
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2379<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2380
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2381<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2382
2383<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2384 &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]2385</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2386
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2387<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2388
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2389<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2390heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2391
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2392<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2393
2394<p>The '<tt>malloc</tt>' instruction allocates
2395<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2396bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2397appropriate type to the program. If "NumElements" is specified, it is the
2398number of elements allocated. If an alignment is specified, the value result
2399of the allocation is guaranteed to be aligned to at least that boundary. If
2400not specified, or if zero, the target can choose to align the allocation on any
2401convenient boundary.</p>
2402
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2403<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2404
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2405<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2406
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2407<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2408a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2409
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2410<h5>Example:</h5>
2411
2412<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2413 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2414
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2415 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2416 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2417 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2418 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2419 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2420</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2421</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2422
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2423<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2424<div class="doc_subsubsection">
2425 <a name="i_free">'<tt>free</tt>' Instruction</a>
2426</div>
2427
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2428<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2429
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2430<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2431
2432<pre>
2433 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2434</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2435
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2436<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2437
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2438<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2439memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2440
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2441<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2442
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2443<p>'<tt>value</tt>' shall be a pointer value that points to a value
2444that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2445instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2446
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2447<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2448
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2449<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2450after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2451
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2452<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2453
2454<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2455 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2456 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2457</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2458</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2459
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2460<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2461<div class="doc_subsubsection">
2462 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2463</div>
2464
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2465<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2466
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2467<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2468
2469<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2470 &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]2471</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2472
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2473<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2474
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2475<p>The '<tt>alloca</tt>' instruction allocates memory on the current
2476stack frame of the procedure that is live until the current function
2477returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2478
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2479<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2480
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2481<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2482bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2483appropriate type to the program. If "NumElements" is specified, it is the
2484number of elements allocated. If an alignment is specified, the value result
2485of the allocation is guaranteed to be aligned to at least that boundary. If
2486not specified, or if zero, the target can choose to align the allocation on any
2487convenient boundary.</p>
2488
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2489<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2490
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2491<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2492
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2493<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2494memory is automatically released when the function returns. The '<tt>alloca</tt>'
2495instruction is commonly used to represent automatic variables that must
2496have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2497 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]2498instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2499
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2500<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2501
2502<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2503 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
2504 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2505 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
2506 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2507</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2508</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2509
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2510<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2511<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2512Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2513<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2514<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2515<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]2516<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2517<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2518<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2519<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2520address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2521 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2522marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2523the number or order of execution of this <tt>load</tt> with other
2524volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2525instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2526<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2527<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2528<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2529<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2530 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2531 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2532 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2533</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2534</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2535<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2536<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2537Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2538<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2539<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2540<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]2541 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]2542</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2543<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2544<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2545<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2546<p>There are two arguments to the '<tt>store</tt>' instruction: a value
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2547to 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]2548operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2549operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2550optimizer is not allowed to modify the number or order of execution of
2551this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2552 href="#i_store">store</a></tt> instructions.</p>
2553<h5>Semantics:</h5>
2554<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2555at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2556<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2557<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2558 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2559 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2560 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2561</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2562</div>
2563
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2564<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2565<div class="doc_subsubsection">
2566 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2567</div>
2568
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2569<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2570<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2571<pre>
2572 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2573</pre>
2574
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2575<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2576
2577<p>
2578The '<tt>getelementptr</tt>' instruction is used to get the address of a
2579subelement of an aggregate data structure.</p>
2580
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2581<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2582
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2583<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2584elements of the aggregate object to index to. The actual types of the arguments
2585provided depend on the type of the first pointer argument. The
2586'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2587levels 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^]2588structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2589into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2590be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2591
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2592<p>For example, let's consider a C code fragment and how it gets
2593compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2594
2595<pre>
2596 struct RT {
2597 char A;
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2598 i32 B[10][20];
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2599 char C;
2600 };
2601 struct ST {
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2602 i32 X;
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2603 double Y;
2604 struct RT Z;
2605 };
2606
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2607 define i32 *foo(struct ST *s) {
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2608 return &amp;s[1].Z.B[5][13];
2609 }
2610</pre>
2611
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2612<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2613
2614<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2615 %RT = type { i8 , [10 x [20 x i32]], i8 }
2616 %ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2617
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2618 implementation
2619
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2620 define i32* %foo(%ST* %s) {
Brian Gaeke317ef962004-07-02 21:08:14 +0000[diff] [blame]2621 entry:
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2622 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2623 ret i32* %reg
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2624 }
2625</pre>
2626
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2627<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2628
2629<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2630on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2631and <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]2632<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^]2633to 64-bits. <a href="#t_struct">Structure</a> types, require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2634<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2635
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2636<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^]2637type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2638}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2639the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2640i8 }</tt>' type, another structure. The third index indexes into the second
2641element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2642array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2643'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2644to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2645
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2646<p>Note that it is perfectly legal to index partially through a
2647structure, returning a pointer to an inner element. Because of this,
2648the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2649
2650<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2651 define i32* %foo(%ST* %s) {
2652 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
2653 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2654 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
2655 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2656 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2657 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2658 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2659</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2660
2661<p>Note that it is undefined to access an array out of bounds: array and
2662pointer indexes must always be within the defined bounds of the array type.
2663The one exception for this rules is zero length arrays. These arrays are
2664defined to be accessible as variable length arrays, which requires access
2665beyond the zero'th element.</p>
2666
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2667<p>The getelementptr instruction is often confusing. For some more insight
2668into how it works, see <a href="GetElementPtr.html">the getelementptr
2669FAQ</a>.</p>
2670
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2671<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2672
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2673<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2674 <i>; yields [12 x i8]*:aptr</i>
2675 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2676</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2677</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2678
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2679<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2680<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2681</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2682<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2683<p>The instructions in this category are the conversion instructions (casting)
2684which all take a single operand and a type. They perform various bit conversions
2685on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2686</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2687
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2688<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2689<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2690 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2691</div>
2692<div class="doc_text">
2693
2694<h5>Syntax:</h5>
2695<pre>
2696 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2697</pre>
2698
2699<h5>Overview:</h5>
2700<p>
2701The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2702</p>
2703
2704<h5>Arguments:</h5>
2705<p>
2706The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2707be an <a href="#t_integer">integer</a> type, and a type that specifies the size
2708and type of the result, which must be an <a href="#t_integral">integral</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2709type. The bit size of <tt>value</tt> must be larger than the bit size of
2710<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2711
2712<h5>Semantics:</h5>
2713<p>
2714The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2715and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2716larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2717It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2718
2719<h5>Example:</h5>
2720<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2721 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
2722 %Y = trunc i32 123 to bool <i>; yields bool:true</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2723</pre>
2724</div>
2725
2726<!-- _______________________________________________________________________ -->
2727<div class="doc_subsubsection">
2728 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2729</div>
2730<div class="doc_text">
2731
2732<h5>Syntax:</h5>
2733<pre>
2734 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2735</pre>
2736
2737<h5>Overview:</h5>
2738<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2739<tt>ty2</tt>.</p>
2740
2741
2742<h5>Arguments:</h5>
2743<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
2744<a href="#t_integral">integral</a> type, and a type to cast it to, which must
2745also be of <a href="#t_integral">integral</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2746<tt>value</tt> must be smaller than the bit size of the destination type,
2747<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2748
2749<h5>Semantics:</h5>
2750<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
2751bits until it reaches the size of the destination type, <tt>ty2</tt>. When the
2752the operand and the type are the same size, no bit filling is done and the
2753cast is considered a <i>no-op cast</i> because no bits change (only the type
2754changes).</p>
2755
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2756<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]2757
2758<h5>Example:</h5>
2759<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2760 %X = zext i32 257 to i64 <i>; yields i64:257</i>
2761 %Y = zext bool true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2762</pre>
2763</div>
2764
2765<!-- _______________________________________________________________________ -->
2766<div class="doc_subsubsection">
2767 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2768</div>
2769<div class="doc_text">
2770
2771<h5>Syntax:</h5>
2772<pre>
2773 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2774</pre>
2775
2776<h5>Overview:</h5>
2777<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2778
2779<h5>Arguments:</h5>
2780<p>
2781The '<tt>sext</tt>' instruction takes a value to cast, which must be of
2782<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]2783also be of <a href="#t_integral">integral</a> type. The bit size of the
2784<tt>value</tt> must be smaller than the bit size of the destination type,
2785<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2786
2787<h5>Semantics:</h5>
2788<p>
2789The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
2790bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
2791the type <tt>ty2</tt>. When the the operand and the type are the same size,
2792no bit filling is done and the cast is considered a <i>no-op cast</i> because
2793no bits change (only the type changes).</p>
2794
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2795<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]2796
2797<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2798<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2799 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
2800 %Y = sext bool true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2801</pre>
2802</div>
2803
2804<!-- _______________________________________________________________________ -->
2805<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2806 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
2807</div>
2808
2809<div class="doc_text">
2810
2811<h5>Syntax:</h5>
2812
2813<pre>
2814 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2815</pre>
2816
2817<h5>Overview:</h5>
2818<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
2819<tt>ty2</tt>.</p>
2820
2821
2822<h5>Arguments:</h5>
2823<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
2824 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
2825cast it to. The size of <tt>value</tt> must be larger than the size of
2826<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
2827<i>no-op cast</i>.</p>
2828
2829<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2830<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
2831<a href="#t_floating">floating point</a> type to a smaller
2832<a href="#t_floating">floating point</a> type. If the value cannot fit within
2833the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]2834
2835<h5>Example:</h5>
2836<pre>
2837 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
2838 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
2839</pre>
2840</div>
2841
2842<!-- _______________________________________________________________________ -->
2843<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2844 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
2845</div>
2846<div class="doc_text">
2847
2848<h5>Syntax:</h5>
2849<pre>
2850 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2851</pre>
2852
2853<h5>Overview:</h5>
2854<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
2855floating point value.</p>
2856
2857<h5>Arguments:</h5>
2858<p>The '<tt>fpext</tt>' instruction takes a
2859<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2860and a <a href="#t_floating">floating point</a> type to cast it to. The source
2861type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2862
2863<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2864<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
2865<a href="t_floating">floating point</a> type to a larger
2866<a href="t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
2867used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2868<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]2869
2870<h5>Example:</h5>
2871<pre>
2872 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
2873 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
2874</pre>
2875</div>
2876
2877<!-- _______________________________________________________________________ -->
2878<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2879 <a name="i_fp2uint">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2880</div>
2881<div class="doc_text">
2882
2883<h5>Syntax:</h5>
2884<pre>
2885 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2886</pre>
2887
2888<h5>Overview:</h5>
2889<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
2890unsigned integer equivalent of type <tt>ty2</tt>.
2891</p>
2892
2893<h5>Arguments:</h5>
2894<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
2895<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2896must be an <a href="#t_integral">integral</a> type.</p>
2897
2898<h5>Semantics:</h5>
2899<p> The '<tt>fp2uint</tt>' instruction converts its
2900<a href="#t_floating">floating point</a> operand into the nearest (rounding
2901towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
2902the results are undefined.</p>
2903
2904<p>When converting to bool, the conversion is done as a comparison against
2905zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2906If the <tt>value</tt> was non-zero, the bool result will be <tt>true</tt>.</p>
2907
2908<h5>Example:</h5>
2909<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2910 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2911 %Y = fp2uint float 1.0E+300 to bool <i>; yields bool:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2912 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2913</pre>
2914</div>
2915
2916<!-- _______________________________________________________________________ -->
2917<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2918 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2919</div>
2920<div class="doc_text">
2921
2922<h5>Syntax:</h5>
2923<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2924 &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]2925</pre>
2926
2927<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2928<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2929<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]2930</p>
2931
2932
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2933<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2934<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]2935<a href="#t_floating">floating point</a> value, and a type to cast it to, which
2936must also be an <a href="#t_integral">integral</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2937
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2938<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2939<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2940<a href="#t_floating">floating point</a> operand into the nearest (rounding
2941towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
2942the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2943
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2944<p>When converting to bool, the conversion is done as a comparison against
2945zero. If the <tt>value</tt> was zero, the bool result will be <tt>false</tt>.
2946If 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]2947
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]2948<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2949<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2950 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2951 %Y = fptosi float 1.0E-247 to bool <i>; yields bool:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2952 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2953</pre>
2954</div>
2955
2956<!-- _______________________________________________________________________ -->
2957<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2958 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2959</div>
2960<div class="doc_text">
2961
2962<h5>Syntax:</h5>
2963<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2964 &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]2965</pre>
2966
2967<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2968<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2969integer and converts that value to the <tt>ty2</tt> type.</p>
2970
2971
2972<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2973<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]2974<a href="#t_integral">integral</a> value, and a type to cast it to, which must
2975be a <a href="#t_floating">floating point</a> type.</p>
2976
2977<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2978<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2979integer quantity and converts it to the corresponding floating point value. If
2980the value cannot fit in the floating point value, the results are undefined.</p>
2981
2982
2983<h5>Example:</h5>
2984<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]2985 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
2986 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2987</pre>
2988</div>
2989
2990<!-- _______________________________________________________________________ -->
2991<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2992 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2993</div>
2994<div class="doc_text">
2995
2996<h5>Syntax:</h5>
2997<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2998 &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]2999</pre>
3000
3001<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3002<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3003integer and converts that value to the <tt>ty2</tt> type.</p>
3004
3005<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3006<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]3007<a href="#t_integral">integral</a> value, and a type to cast it to, which must be
3008a <a href="#t_floating">floating point</a> type.</p>
3009
3010<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3011<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3012integer quantity and converts it to the corresponding floating point value. If
3013the value cannot fit in the floating point value, the results are undefined.</p>
3014
3015<h5>Example:</h5>
3016<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3017 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
3018 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3019</pre>
3020</div>
3021
3022<!-- _______________________________________________________________________ -->
3023<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3024 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3025</div>
3026<div class="doc_text">
3027
3028<h5>Syntax:</h5>
3029<pre>
3030 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3031</pre>
3032
3033<h5>Overview:</h5>
3034<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3035the integer type <tt>ty2</tt>.</p>
3036
3037<h5>Arguments:</h5>
3038<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
3039must be a <a href="t_pointer">pointer</a> value, and a type to cast it to
3040<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3041
3042<h5>Semantics:</h5>
3043<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3044<tt>ty2</tt> by interpreting the pointer value as an integer and either
3045truncating or zero extending that value to the size of the integer type. If
3046<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3047<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
3048are the same size, then nothing is done (<i>no-op cast</i>).</p>
3049
3050<h5>Example:</h5>
3051<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3052 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit</i>
3053 %Y = ptrtoint i32* %x to i64 <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3054</pre>
3055</div>
3056
3057<!-- _______________________________________________________________________ -->
3058<div class="doc_subsubsection">
3059 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3060</div>
3061<div class="doc_text">
3062
3063<h5>Syntax:</h5>
3064<pre>
3065 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3066</pre>
3067
3068<h5>Overview:</h5>
3069<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3070a pointer type, <tt>ty2</tt>.</p>
3071
3072<h5>Arguments:</h5>
3073<p>The '<tt>inttoptr</tt>' instruction takes an <a href="i_integer">integer</a>
3074value to cast, and a type to cast it to, which must be a
3075<a href="#t_pointer">pointer</a> type. </tt>
3076
3077<h5>Semantics:</h5>
3078<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3079<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3080the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3081size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3082the size of a pointer then a zero extension is done. If they are the same size,
3083nothing is done (<i>no-op cast</i>).</p>
3084
3085<h5>Example:</h5>
3086<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3087 %X = inttoptr i32 255 to i32* <i>; yields zero extend on 64-bit</i>
3088 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit </i>
3089 %Y = inttoptr i16 0 to i32* <i>; yields zero extend on 32-bit</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3090</pre>
3091</div>
3092
3093<!-- _______________________________________________________________________ -->
3094<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3095 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3096</div>
3097<div class="doc_text">
3098
3099<h5>Syntax:</h5>
3100<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3101 &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]3102</pre>
3103
3104<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3105<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3106<tt>ty2</tt> without changing any bits.</p>
3107
3108<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3109<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3110a first class value, and a type to cast it to, which must also be a <a
3111 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
3112and the destination type, <tt>ty2</tt>, must be identical.</p>
3113
3114<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3115<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3116<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3117this conversion. The conversion is done as if the <tt>value</tt> had been
3118stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3119converted to other pointer types with this instruction. To convert pointers to
3120other types, use the <a href="#i_inttoptr">inttoptr</a> or
3121<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3122
3123<h5>Example:</h5>
3124<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3125 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
3126 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3127 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3128</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3129</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3130
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3131<!-- ======================================================================= -->
3132<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3133<div class="doc_text">
3134<p>The instructions in this category are the "miscellaneous"
3135instructions, which defy better classification.</p>
3136</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3137
3138<!-- _______________________________________________________________________ -->
3139<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3140</div>
3141<div class="doc_text">
3142<h5>Syntax:</h5>
3143<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3144</pre>
3145<h5>Overview:</h5>
3146<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3147of its two integer operands.</p>
3148<h5>Arguments:</h5>
3149<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
3150the condition code which indicates the kind of comparison to perform. It is not
3151a value, just a keyword. The possibilities for the condition code are:
3152<ol>
3153 <li><tt>eq</tt>: equal</li>
3154 <li><tt>ne</tt>: not equal </li>
3155 <li><tt>ugt</tt>: unsigned greater than</li>
3156 <li><tt>uge</tt>: unsigned greater or equal</li>
3157 <li><tt>ult</tt>: unsigned less than</li>
3158 <li><tt>ule</tt>: unsigned less or equal</li>
3159 <li><tt>sgt</tt>: signed greater than</li>
3160 <li><tt>sge</tt>: signed greater or equal</li>
3161 <li><tt>slt</tt>: signed less than</li>
3162 <li><tt>sle</tt>: signed less or equal</li>
3163</ol>
3164<p>The remaining two arguments must be of <a href="#t_integral">integral</a>,
3165<a href="#t_pointer">pointer</a> or a <a href="#t_packed">packed</a> integral
3166type. They must have identical types.</p>
3167<h5>Semantics:</h5>
3168<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3169the condition code given as <tt>cond</tt>. The comparison performed always
3170yields a <a href="#t_bool">bool</a> result, as follows:
3171<ol>
3172 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3173 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3174 </li>
3175 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3176 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3177 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3178 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3179 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3180 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3181 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3182 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3183 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3184 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3185 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3186 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3187 <li><tt>sge</tt>: interprets the operands as signed values and yields
3188 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3189 <li><tt>slt</tt>: interprets the operands as signed values and yields
3190 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3191 <li><tt>sle</tt>: interprets the operands as signed values and yields
3192 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3193 </li>
3194</ol>
3195<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
3196values are treated as integers and then compared.</p>
3197<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]3198the vector are compared in turn and the predicate must hold for all
3199elements.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3200
3201<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3202<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3203 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3204 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3205 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3206 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3207 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3208</pre>
3209</div>
3210
3211<!-- _______________________________________________________________________ -->
3212<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3213</div>
3214<div class="doc_text">
3215<h5>Syntax:</h5>
3216<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {bool}:result</i>
3217</pre>
3218<h5>Overview:</h5>
3219<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3220of its floating point operands.</p>
3221<h5>Arguments:</h5>
3222<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
3223the condition code which indicates the kind of comparison to perform. It is not
3224a value, just a keyword. The possibilities for the condition code are:
3225<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3226 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3227 <li><tt>oeq</tt>: ordered and equal</li>
3228 <li><tt>ogt</tt>: ordered and greater than </li>
3229 <li><tt>oge</tt>: ordered and greater than or equal</li>
3230 <li><tt>olt</tt>: ordered and less than </li>
3231 <li><tt>ole</tt>: ordered and less than or equal</li>
3232 <li><tt>one</tt>: ordered and not equal</li>
3233 <li><tt>ord</tt>: ordered (no nans)</li>
3234 <li><tt>ueq</tt>: unordered or equal</li>
3235 <li><tt>ugt</tt>: unordered or greater than </li>
3236 <li><tt>uge</tt>: unordered or greater than or equal</li>
3237 <li><tt>ult</tt>: unordered or less than </li>
3238 <li><tt>ule</tt>: unordered or less than or equal</li>
3239 <li><tt>une</tt>: unordered or not equal</li>
3240 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3241 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3242</ol>
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3243<p>In the preceding, <i>ordered</i> means that neither operand is a QNAN while
3244<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3245<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be of
3246<a href="#t_floating">floating point</a>, or a <a href="#t_packed">packed</a>
3247floating point type. They must have identical types.</p>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3248<p>In the foregoing, <i>ordered</i> means that neither operand is a QNAN and
3249<i>unordered</i> means that either operand is a QNAN.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3250<h5>Semantics:</h5>
3251<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3252the condition code given as <tt>cond</tt>. The comparison performed always
3253yields a <a href="#t_bool">bool</a> result, as follows:
3254<ol>
3255 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3256 <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]3257 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3258 <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]3259 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3260 <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]3261 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3262 <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]3263 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3264 <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]3265 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3266 <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]3267 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3268 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3269 <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]3270 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3271 <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]3272 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3273 <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]3274 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3275 <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]3276 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3277 <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]3278 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3279 <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]3280 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3281 <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]3282 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3283</ol>
3284<p>If the operands are <a href="#t_packed">packed</a> typed, the elements of
3285the vector are compared in turn and the predicate must hold for all elements.
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3286</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3287
3288<h5>Example:</h5>
3289<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3290 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3291 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3292 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3293</pre>
3294</div>
3295
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3296<!-- _______________________________________________________________________ -->
3297<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3298Instruction</a> </div>
3299<div class="doc_text">
3300<h5>Syntax:</h5>
3301<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3302<h5>Overview:</h5>
3303<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3304the SSA graph representing the function.</p>
3305<h5>Arguments:</h5>
3306<p>The type of the incoming values are specified with the first type
3307field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3308as arguments, with one pair for each predecessor basic block of the
3309current block. Only values of <a href="#t_firstclass">first class</a>
3310type may be used as the value arguments to the PHI node. Only labels
3311may be used as the label arguments.</p>
3312<p>There must be no non-phi instructions between the start of a basic
3313block and the PHI instructions: i.e. PHI instructions must be first in
3314a basic block.</p>
3315<h5>Semantics:</h5>
3316<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the
3317value specified by the parameter, depending on which basic block we
3318came from in the last <a href="#terminators">terminator</a> instruction.</p>
3319<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3320<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]3321</div>
3322
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3323<!-- _______________________________________________________________________ -->
3324<div class="doc_subsubsection">
3325 <a name="i_select">'<tt>select</tt>' Instruction</a>
3326</div>
3327
3328<div class="doc_text">
3329
3330<h5>Syntax:</h5>
3331
3332<pre>
3333 &lt;result&gt; = select bool &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
3334</pre>
3335
3336<h5>Overview:</h5>
3337
3338<p>
3339The '<tt>select</tt>' instruction is used to choose one value based on a
3340condition, without branching.
3341</p>
3342
3343
3344<h5>Arguments:</h5>
3345
3346<p>
3347The '<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.
3348</p>
3349
3350<h5>Semantics:</h5>
3351
3352<p>
3353If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3354value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3355</p>
3356
3357<h5>Example:</h5>
3358
3359<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3360 %X = select bool true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3361</pre>
3362</div>
3363
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3364
3365<!-- _______________________________________________________________________ -->
3366<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3367 <a name="i_call">'<tt>call</tt>' Instruction</a>
3368</div>
3369
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3370<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3371
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3372<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3373<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3374 &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]3375</pre>
3376
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3377<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3378
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3379<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3380
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3381<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3382
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3383<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3384
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3385<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3386 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3387 <p>The optional "tail" marker indicates whether the callee function accesses
3388 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3389 function call is eligible for tail call optimization. Note that calls may
3390 be marked "tail" even if they do not occur before a <a
3391 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3392 </li>
3393 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3394 <p>The optional "cconv" marker indicates which <a href="callingconv">calling
3395 convention</a> the call should use. If none is specified, the call defaults
3396 to using C calling conventions.
3397 </li>
3398 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3399 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3400 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3401 signature. This type can be omitted if the function is not varargs and
3402 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3403 </li>
3404 <li>
3405 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3406 be invoked. In most cases, this is a direct function invocation, but
3407 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3408 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3409 </li>
3410 <li>
3411 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3412 function signature argument types. All arguments must be of
3413 <a href="#t_firstclass">first class</a> type. If the function signature
3414 indicates the function accepts a variable number of arguments, the extra
3415 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3416 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3417</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3418
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3419<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3420
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3421<p>The '<tt>call</tt>' instruction is used to cause control flow to
3422transfer to a specified function, with its incoming arguments bound to
3423the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3424instruction in the called function, control flow continues with the
3425instruction after the function call, and the return value of the
3426function is bound to the result argument. This is a simpler case of
3427the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3428
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3429<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3430
3431<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3432 %retval = call i32 %test(i32 %argc)
3433 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
3434 %X = tail call i32 %foo()
3435 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3436</pre>
3437
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3438</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3439
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3440<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3441<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3442 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3443</div>
3444
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3445<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3446
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3447<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3448
3449<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3450 &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]3451</pre>
3452
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3453<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3454
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3455<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3456the "variable argument" area of a function call. It is used to implement the
3457<tt>va_arg</tt> macro in C.</p>
3458
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3459<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3460
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3461<p>This instruction takes a <tt>va_list*</tt> value and the type of
3462the argument. It returns a value of the specified argument type and
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]3463increments the <tt>va_list</tt> to point to the next argument. Again, the
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3464actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3465
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3466<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3467
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3468<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3469type from the specified <tt>va_list</tt> and causes the
3470<tt>va_list</tt> to point to the next argument. For more information,
3471see the variable argument handling <a href="#int_varargs">Intrinsic
3472Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3473
3474<p>It is legal for this instruction to be called in a function which does not
3475take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3476function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3477
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3478<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3479href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3480argument.</p>
3481
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3482<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3483
3484<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3485
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3486</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3487
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3488<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3489<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3490<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3491
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3492<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3493
3494<p>LLVM supports the notion of an "intrinsic function". These functions have
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3495well known names and semantics and are required to follow certain
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3496restrictions. Overall, these instructions represent an extension mechanism for
3497the LLVM language that does not require changing all of the transformations in
3498LLVM to add to the language (or the bytecode reader/writer, the parser,
3499etc...).</p>
3500
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3501<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
3502prefix is reserved in LLVM for intrinsic names; thus, functions may not be named
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3503this. Intrinsic functions must always be external functions: you cannot define
3504the body of intrinsic functions. Intrinsic functions may only be used in call
3505or invoke instructions: it is illegal to take the address of an intrinsic
3506function. Additionally, because intrinsic functions are part of the LLVM
3507language, it is required that they all be documented here if any are added.</p>
3508
3509
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3510<p>To learn how to add an intrinsic function, please see the <a
Chris Lattner90391c12005-05-11 03:35:57 +0000[diff] [blame]3511href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3512</p>
3513
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3514</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3515
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3516<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3517<div class="doc_subsection">
3518 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3519</div>
3520
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3521<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3522
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3523<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3524 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3525intrinsic functions. These functions are related to the similarly
3526named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3527
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3528<p>All of these functions operate on arguments that use a
3529target-specific value type "<tt>va_list</tt>". The LLVM assembly
3530language reference manual does not define what this type is, so all
3531transformations should be prepared to handle intrinsics with any type
3532used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3533
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3534<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]3535instruction and the variable argument handling intrinsic functions are
3536used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3537
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3538<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3539define i32 %test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3540 ; Initialize variable argument processing
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3541 %ap = alloca i8 *
3542 call void %<a href="#i_va_start">llvm.va_start</a>(i8 ** %ap)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3543
3544 ; Read a single integer argument
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3545 %tmp = va_arg i8 ** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3546
3547 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3548 %aq = alloca i8 *
3549 call void %<a href="#i_va_copy">llvm.va_copy</a>(i8 ** %aq, i8 ** %ap)
3550 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %aq)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3551
3552 ; Stop processing of arguments.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3553 call void %<a href="#i_va_end">llvm.va_end</a>(i8 ** %ap)
3554 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3555}
3556</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3557</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3558
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3559<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3560<div class="doc_subsubsection">
3561 <a name="i_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
3562</div>
3563
3564
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3565<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3566<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3567<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]3568<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3569<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3570<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3571href="#i_va_arg">va_arg</a></tt>.</p>
3572
3573<h5>Arguments:</h5>
3574
3575<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3576
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3577<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3578
3579<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3580macro available in C. In a target-dependent way, it initializes the
3581<tt>va_list</tt> element the argument points to, so that the next call to
3582<tt>va_arg</tt> will produce the first variable argument passed to the function.
3583Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
3584last argument of the function, the compiler can figure that out.</p>
3585
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_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
3591</div>
3592
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3593<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3594<h5>Syntax:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3595<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]3596<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3597<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>&lt;arglist&gt;</tt>
3598which has been initialized previously with <tt><a href="#i_va_start">llvm.va_start</a></tt>
3599or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3600<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3601<p>The argument is a <tt>va_list</tt> to destroy.</p>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3602<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3603<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]3604macro available in C. In a target-dependent way, it destroys the <tt>va_list</tt>.
3605Calls to <a href="#i_va_start"><tt>llvm.va_start</tt></a> and <a
3606 href="#i_va_copy"><tt>llvm.va_copy</tt></a> must be matched exactly
3607with calls to <tt>llvm.va_end</tt>.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3608</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3609
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3610<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3611<div class="doc_subsubsection">
3612 <a name="i_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
3613</div>
3614
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3615<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3616
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3617<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3618
3619<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3620 declare void %llvm.va_copy(&lt;va_list&gt;* &lt;destarglist&gt;,
Andrew Lenharth5305ea52005-06-22 20:38:11 +0000[diff] [blame]3621 &lt;va_list&gt;* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3622</pre>
3623
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3624<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3625
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3626<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position from
3627the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3628
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3629<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3630
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3631<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]3632The 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]3633
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3634
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3635<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3636
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3637<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt> macro
3638available in C. In a target-dependent way, it copies the source
3639<tt>va_list</tt> element into the destination list. This intrinsic is necessary
3640because 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]3641arbitrarily complex and require memory allocation, for example.</p>
3642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3643</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3644
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3645<!-- ======================================================================= -->
3646<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3647 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3648</div>
3649
3650<div class="doc_text">
3651
3652<p>
3653LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3654Collection</a> requires the implementation and generation of these intrinsics.
3655These intrinsics allow identification of <a href="#i_gcroot">GC roots on the
3656stack</a>, as well as garbage collector implementations that require <a
3657href="#i_gcread">read</a> and <a href="#i_gcwrite">write</a> barriers.
3658Front-ends for type-safe garbage collected languages should generate these
3659intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3660href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3661</p>
3662</div>
3663
3664<!-- _______________________________________________________________________ -->
3665<div class="doc_subsubsection">
3666 <a name="i_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
3667</div>
3668
3669<div class="doc_text">
3670
3671<h5>Syntax:</h5>
3672
3673<pre>
Reid Spencer7821d062005-04-26 20:50:44 +0000[diff] [blame]3674 declare void %llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3675</pre>
3676
3677<h5>Overview:</h5>
3678
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3679<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]3680the code generator, and allows some metadata to be associated with it.</p>
3681
3682<h5>Arguments:</h5>
3683
3684<p>The first argument specifies the address of a stack object that contains the
3685root pointer. The second pointer (which must be either a constant or a global
3686value address) contains the meta-data to be associated with the root.</p>
3687
3688<h5>Semantics:</h5>
3689
3690<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3691location. At compile-time, the code generator generates information to allow
3692the runtime to find the pointer at GC safe points.
3693</p>
3694
3695</div>
3696
3697
3698<!-- _______________________________________________________________________ -->
3699<div class="doc_subsubsection">
3700 <a name="i_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
3701</div>
3702
3703<div class="doc_text">
3704
3705<h5>Syntax:</h5>
3706
3707<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3708 declare i8 * %llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3709</pre>
3710
3711<h5>Overview:</h5>
3712
3713<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3714locations, allowing garbage collector implementations that require read
3715barriers.</p>
3716
3717<h5>Arguments:</h5>
3718
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3719<p>The second argument is the address to read from, which should be an address
3720allocated from the garbage collector. The first object is a pointer to the
3721start of the referenced object, if needed by the language runtime (otherwise
3722null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3723
3724<h5>Semantics:</h5>
3725
3726<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3727instruction, but may be replaced with substantially more complex code by the
3728garbage collector runtime, as needed.</p>
3729
3730</div>
3731
3732
3733<!-- _______________________________________________________________________ -->
3734<div class="doc_subsubsection">
3735 <a name="i_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
3736</div>
3737
3738<div class="doc_text">
3739
3740<h5>Syntax:</h5>
3741
3742<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3743 declare void %llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3744</pre>
3745
3746<h5>Overview:</h5>
3747
3748<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3749locations, allowing garbage collector implementations that require write
3750barriers (such as generational or reference counting collectors).</p>
3751
3752<h5>Arguments:</h5>
3753
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3754<p>The first argument is the reference to store, the second is the start of the
3755object to store it to, and the third is the address of the field of Obj to
3756store to. If the runtime does not require a pointer to the object, Obj may be
3757null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3758
3759<h5>Semantics:</h5>
3760
3761<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3762instruction, but may be replaced with substantially more complex code by the
3763garbage collector runtime, as needed.</p>
3764
3765</div>
3766
3767
3768
3769<!-- ======================================================================= -->
3770<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3771 <a name="int_codegen">Code Generator Intrinsics</a>
3772</div>
3773
3774<div class="doc_text">
3775<p>
3776These intrinsics are provided by LLVM to expose special features that may only
3777be implemented with code generator support.
3778</p>
3779
3780</div>
3781
3782<!-- _______________________________________________________________________ -->
3783<div class="doc_subsubsection">
3784 <a name="i_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
3785</div>
3786
3787<div class="doc_text">
3788
3789<h5>Syntax:</h5>
3790<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3791 declare i8 *%llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3792</pre>
3793
3794<h5>Overview:</h5>
3795
3796<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3797The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
3798target-specific value indicating the return address of the current function
3799or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3800</p>
3801
3802<h5>Arguments:</h5>
3803
3804<p>
3805The argument to this intrinsic indicates which function to return the address
3806for. Zero indicates the calling function, one indicates its caller, etc. The
3807argument is <b>required</b> to be a constant integer value.
3808</p>
3809
3810<h5>Semantics:</h5>
3811
3812<p>
3813The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
3814the return address of the specified call frame, or zero if it cannot be
3815identified. The value returned by this intrinsic is likely to be incorrect or 0
3816for arguments other than zero, so it should only be used for debugging purposes.
3817</p>
3818
3819<p>
3820Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3821aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3822source-language caller.
3823</p>
3824</div>
3825
3826
3827<!-- _______________________________________________________________________ -->
3828<div class="doc_subsubsection">
3829 <a name="i_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
3830</div>
3831
3832<div class="doc_text">
3833
3834<h5>Syntax:</h5>
3835<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3836 declare i8 *%llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3837</pre>
3838
3839<h5>Overview:</h5>
3840
3841<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]3842The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
3843target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3844</p>
3845
3846<h5>Arguments:</h5>
3847
3848<p>
3849The argument to this intrinsic indicates which function to return the frame
3850pointer for. Zero indicates the calling function, one indicates its caller,
3851etc. The argument is <b>required</b> to be a constant integer value.
3852</p>
3853
3854<h5>Semantics:</h5>
3855
3856<p>
3857The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
3858the frame address of the specified call frame, or zero if it cannot be
3859identified. The value returned by this intrinsic is likely to be incorrect or 0
3860for arguments other than zero, so it should only be used for debugging purposes.
3861</p>
3862
3863<p>
3864Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]3865aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]3866source-language caller.
3867</p>
3868</div>
3869
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3870<!-- _______________________________________________________________________ -->
3871<div class="doc_subsubsection">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3872 <a name="i_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
3873</div>
3874
3875<div class="doc_text">
3876
3877<h5>Syntax:</h5>
3878<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3879 declare i8 *%llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3880</pre>
3881
3882<h5>Overview:</h5>
3883
3884<p>
3885The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
3886the function stack, for use with <a href="#i_stackrestore">
3887<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
3888features like scoped automatic variable sized arrays in C99.
3889</p>
3890
3891<h5>Semantics:</h5>
3892
3893<p>
3894This intrinsic returns a opaque pointer value that can be passed to <a
3895href="#i_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
3896<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
3897<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
3898state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
3899practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
3900that were allocated after the <tt>llvm.stacksave</tt> was executed.
3901</p>
3902
3903</div>
3904
3905<!-- _______________________________________________________________________ -->
3906<div class="doc_subsubsection">
3907 <a name="i_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
3908</div>
3909
3910<div class="doc_text">
3911
3912<h5>Syntax:</h5>
3913<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3914 declare void %llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]3915</pre>
3916
3917<h5>Overview:</h5>
3918
3919<p>
3920The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
3921the function stack to the state it was in when the corresponding <a
3922href="#llvm.stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
3923useful for implementing language features like scoped automatic variable sized
3924arrays in C99.
3925</p>
3926
3927<h5>Semantics:</h5>
3928
3929<p>
3930See the description for <a href="#i_stacksave"><tt>llvm.stacksave</tt></a>.
3931</p>
3932
3933</div>
3934
3935
3936<!-- _______________________________________________________________________ -->
3937<div class="doc_subsubsection">
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3938 <a name="i_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
3939</div>
3940
3941<div class="doc_text">
3942
3943<h5>Syntax:</h5>
3944<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3945 declare void %llvm.prefetch(i8 * &lt;address&gt;,
3946 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3947</pre>
3948
3949<h5>Overview:</h5>
3950
3951
3952<p>
3953The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3954a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
3955no
3956effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]3957characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3958</p>
3959
3960<h5>Arguments:</h5>
3961
3962<p>
3963<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
3964determining if the fetch should be for a read (0) or write (1), and
3965<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]3966locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]3967<tt>locality</tt> arguments must be constant integers.
3968</p>
3969
3970<h5>Semantics:</h5>
3971
3972<p>
3973This intrinsic does not modify the behavior of the program. In particular,
3974prefetches cannot trap and do not produce a value. On targets that support this
3975intrinsic, the prefetch can provide hints to the processor cache for better
3976performance.
3977</p>
3978
3979</div>
3980
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3981<!-- _______________________________________________________________________ -->
3982<div class="doc_subsubsection">
3983 <a name="i_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
3984</div>
3985
3986<div class="doc_text">
3987
3988<h5>Syntax:</h5>
3989<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]3990 declare void %llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3991</pre>
3992
3993<h5>Overview:</h5>
3994
3995
3996<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3997The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
3998(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]3999code to simulators and other tools. The method is target specific, but it is
4000expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4001The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4002after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4003optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4004correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4005</p>
4006
4007<h5>Arguments:</h5>
4008
4009<p>
4010<tt>id</tt> is a numerical id identifying the marker.
4011</p>
4012
4013<h5>Semantics:</h5>
4014
4015<p>
4016This intrinsic does not modify the behavior of the program. Backends that do not
4017support this intrinisic may ignore it.
4018</p>
4019
4020</div>
4021
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4022<!-- _______________________________________________________________________ -->
4023<div class="doc_subsubsection">
4024 <a name="i_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
4025</div>
4026
4027<div class="doc_text">
4028
4029<h5>Syntax:</h5>
4030<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4031 declare i64 %llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4032</pre>
4033
4034<h5>Overview:</h5>
4035
4036
4037<p>
4038The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4039counter register (or similar low latency, high accuracy clocks) on those targets
4040that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4041As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4042should only be used for small timings.
4043</p>
4044
4045<h5>Semantics:</h5>
4046
4047<p>
4048When directly supported, reading the cycle counter should not modify any memory.
4049Implementations are allowed to either return a application specific value or a
4050system wide value. On backends without support, this is lowered to a constant 0.
4051</p>
4052
4053</div>
4054
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4055<!-- ======================================================================= -->
4056<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4057 <a name="int_libc">Standard C Library Intrinsics</a>
4058</div>
4059
4060<div class="doc_text">
4061<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4062LLVM provides intrinsics for a few important standard C library functions.
4063These intrinsics allow source-language front-ends to pass information about the
4064alignment of the pointer arguments to the code generator, providing opportunity
4065for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4066</p>
4067
4068</div>
4069
4070<!-- _______________________________________________________________________ -->
4071<div class="doc_subsubsection">
4072 <a name="i_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
4073</div>
4074
4075<div class="doc_text">
4076
4077<h5>Syntax:</h5>
4078<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4079 declare void %llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4080 i32 &lt;len&gt;, i32 &lt;align&gt;)
4081 declare void %llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4082 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4083</pre>
4084
4085<h5>Overview:</h5>
4086
4087<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4088The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4089location to the destination location.
4090</p>
4091
4092<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4093Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4094intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4095</p>
4096
4097<h5>Arguments:</h5>
4098
4099<p>
4100The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4101the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4102specifying the number of bytes to copy, and the fourth argument is the alignment
4103of the source and destination locations.
4104</p>
4105
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4106<p>
4107If 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]4108the caller guarantees that both the source and destination pointers are aligned
4109to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4110</p>
4111
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4112<h5>Semantics:</h5>
4113
4114<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4115The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4116location to the destination location, which are not allowed to overlap. It
4117copies "len" bytes of memory over. If the argument is known to be aligned to
4118some boundary, this can be specified as the fourth argument, otherwise it should
4119be set to 0 or 1.
4120</p>
4121</div>
4122
4123
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4124<!-- _______________________________________________________________________ -->
4125<div class="doc_subsubsection">
4126 <a name="i_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
4127</div>
4128
4129<div class="doc_text">
4130
4131<h5>Syntax:</h5>
4132<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4133 declare void %llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4134 i32 &lt;len&gt;, i32 &lt;align&gt;)
4135 declare void %llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
4136 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4137</pre>
4138
4139<h5>Overview:</h5>
4140
4141<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4142The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4143location to the destination location. It is similar to the
4144'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4145</p>
4146
4147<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4148Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4149intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4150</p>
4151
4152<h5>Arguments:</h5>
4153
4154<p>
4155The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4156the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4157specifying the number of bytes to copy, and the fourth argument is the alignment
4158of the source and destination locations.
4159</p>
4160
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4161<p>
4162If 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]4163the caller guarantees that the source and destination pointers are aligned to
4164that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4165</p>
4166
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4167<h5>Semantics:</h5>
4168
4169<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4170The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4171location to the destination location, which may overlap. It
4172copies "len" bytes of memory over. If the argument is known to be aligned to
4173some boundary, this can be specified as the fourth argument, otherwise it should
4174be set to 0 or 1.
4175</p>
4176</div>
4177
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4178
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4179<!-- _______________________________________________________________________ -->
4180<div class="doc_subsubsection">
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4181 <a name="i_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4182</div>
4183
4184<div class="doc_text">
4185
4186<h5>Syntax:</h5>
4187<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4188 declare void %llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4189 i32 &lt;len&gt;, i32 &lt;align&gt;)
4190 declare void %llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
4191 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4192</pre>
4193
4194<h5>Overview:</h5>
4195
4196<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4197The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4198byte value.
4199</p>
4200
4201<p>
4202Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4203does not return a value, and takes an extra alignment argument.
4204</p>
4205
4206<h5>Arguments:</h5>
4207
4208<p>
4209The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4210byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4211argument specifying the number of bytes to fill, and the fourth argument is the
4212known alignment of destination location.
4213</p>
4214
4215<p>
4216If 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]4217the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4218</p>
4219
4220<h5>Semantics:</h5>
4221
4222<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4223The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4224the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4225destination location. If the argument is known to be aligned to some boundary,
4226this can be specified as the fourth argument, otherwise it should be set to 0 or
42271.
4228</p>
4229</div>
4230
4231
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4232<!-- _______________________________________________________________________ -->
4233<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4234 <a name="i_isunordered">'<tt>llvm.isunordered.*</tt>' Intrinsic</a>
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4235</div>
4236
4237<div class="doc_text">
4238
4239<h5>Syntax:</h5>
4240<pre>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4241 declare bool %llvm.isunordered.f32(float Val1, float Val2)
4242 declare bool %llvm.isunordered.f64(double Val1, double Val2)
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4243</pre>
4244
4245<h5>Overview:</h5>
4246
4247<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4248The '<tt>llvm.isunordered</tt>' intrinsics return true if either or both of the
Alkis Evlogimenos0fa39232004-06-13 01:16:15 +0000[diff] [blame]4249specified floating point values is a NAN.
4250</p>
4251
4252<h5>Arguments:</h5>
4253
4254<p>
4255The arguments are floating point numbers of the same type.
4256</p>
4257
4258<h5>Semantics:</h5>
4259
4260<p>
4261If either or both of the arguments is a SNAN or QNAN, it returns true, otherwise
4262false.
4263</p>
4264</div>
4265
4266
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4267<!-- _______________________________________________________________________ -->
4268<div class="doc_subsubsection">
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4269 <a name="i_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4270</div>
4271
4272<div class="doc_text">
4273
4274<h5>Syntax:</h5>
4275<pre>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4276 declare float %llvm.sqrt.f32(float %Val)
4277 declare double %llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4278</pre>
4279
4280<h5>Overview:</h5>
4281
4282<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4283The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4284returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4285<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4286negative numbers (which allows for better optimization).
4287</p>
4288
4289<h5>Arguments:</h5>
4290
4291<p>
4292The argument and return value are floating point numbers of the same type.
4293</p>
4294
4295<h5>Semantics:</h5>
4296
4297<p>
4298This function returns the sqrt of the specified operand if it is a positive
4299floating point number.
4300</p>
4301</div>
4302
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4303<!-- _______________________________________________________________________ -->
4304<div class="doc_subsubsection">
4305 <a name="i_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
4306</div>
4307
4308<div class="doc_text">
4309
4310<h5>Syntax:</h5>
4311<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4312 declare float %llvm.powi.f32(float %Val, i32 %power)
4313 declare double %llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4314</pre>
4315
4316<h5>Overview:</h5>
4317
4318<p>
4319The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4320specified (positive or negative) power. The order of evaluation of
4321multiplications is not defined.
4322</p>
4323
4324<h5>Arguments:</h5>
4325
4326<p>
4327The second argument is an integer power, and the first is a value to raise to
4328that power.
4329</p>
4330
4331<h5>Semantics:</h5>
4332
4333<p>
4334This function returns the first value raised to the second power with an
4335unspecified sequence of rounding operations.</p>
4336</div>
4337
4338
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4339<!-- ======================================================================= -->
4340<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4341 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4342</div>
4343
4344<div class="doc_text">
4345<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4346LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4347These allow efficient code generation for some algorithms.
4348</p>
4349
4350</div>
4351
4352<!-- _______________________________________________________________________ -->
4353<div class="doc_subsubsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4354 <a name="i_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
4355</div>
4356
4357<div class="doc_text">
4358
4359<h5>Syntax:</h5>
4360<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4361 declare i16 %llvm.bswap.i16(i16 &lt;id&gt;)
4362 declare i32 %llvm.bswap.i32(i32 &lt;id&gt;)
4363 declare i64 %llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4364</pre>
4365
4366<h5>Overview:</h5>
4367
4368<p>
4369The '<tt>llvm.bwsap</tt>' family of intrinsics is used to byteswap a 16, 32 or
437064 bit quantity. These are useful for performing operations on data that is not
4371in the target's native byte order.
4372</p>
4373
4374<h5>Semantics:</h5>
4375
4376<p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4377The <tt>llvm.bswap.16</tt> intrinsic returns an i16 value that has the high
4378and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4379intrinsic returns an i32 value that has the four bytes of the input i32
4380swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
4381i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i64</tt>
4382intrinsic extends this concept to 64 bits.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4383</p>
4384
4385</div>
4386
4387<!-- _______________________________________________________________________ -->
4388<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4389 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4390</div>
4391
4392<div class="doc_text">
4393
4394<h5>Syntax:</h5>
4395<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4396 declare i8 %llvm.ctpop.i8 (i8 &lt;src&gt;)
4397 declare i16 %llvm.ctpop.i16(i16 &lt;src&gt;)
4398 declare i32 %llvm.ctpop.i32(i32 &lt;src&gt;)
4399 declare i64 %llvm.ctpop.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4400</pre>
4401
4402<h5>Overview:</h5>
4403
4404<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4405The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4406value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4407</p>
4408
4409<h5>Arguments:</h5>
4410
4411<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4412The only argument is the value to be counted. The argument may be of any
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4413unsigned integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4414</p>
4415
4416<h5>Semantics:</h5>
4417
4418<p>
4419The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4420</p>
4421</div>
4422
4423<!-- _______________________________________________________________________ -->
4424<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4425 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4426</div>
4427
4428<div class="doc_text">
4429
4430<h5>Syntax:</h5>
4431<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4432 declare i8 %llvm.ctlz.i8 (i8 &lt;src&gt;)
4433 declare i16 %llvm.ctlz.i16(i16 &lt;src&gt;)
4434 declare i32 %llvm.ctlz.i32(i32 &lt;src&gt;)
4435 declare i64 %llvm.ctlz.i64(i64 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4436</pre>
4437
4438<h5>Overview:</h5>
4439
4440<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4441The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4442leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4443</p>
4444
4445<h5>Arguments:</h5>
4446
4447<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4448The only argument is the value to be counted. The argument may be of any
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4449unsigned integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4450</p>
4451
4452<h5>Semantics:</h5>
4453
4454<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4455The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4456in 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^]4457of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4458</p>
4459</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4460
4461
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4462
4463<!-- _______________________________________________________________________ -->
4464<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4465 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4466</div>
4467
4468<div class="doc_text">
4469
4470<h5>Syntax:</h5>
4471<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame^]4472 declare i8 %llvm.cttz.i8 (i8 &lt;src&gt;)
4473 declare i16 %llvm.cttz.i16(i16 &lt;src&gt;)
4474 declare i32 %llvm.cttz.i32(i32 &lt;src&gt;)
4475 declare i64 %llvm.cttz.i64(i64 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4476</pre>
4477
4478<h5>Overview:</h5>
4479
4480<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4481The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4482trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4483</p>
4484
4485<h5>Arguments:</h5>
4486
4487<p>
4488The only argument is the value to be counted. The argument may be of any
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4489unsigned integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4490</p>
4491
4492<h5>Semantics:</h5>
4493
4494<p>
4495The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4496in a variable. If the src == 0 then the result is the size in bits of the type
4497of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4498</p>
4499</div>
4500
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4501<!-- ======================================================================= -->
4502<div class="doc_subsection">
4503 <a name="int_debugger">Debugger Intrinsics</a>
4504</div>
4505
4506<div class="doc_text">
4507<p>
4508The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4509are described in the <a
4510href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4511Debugging</a> document.
4512</p>
4513</div>
4514
4515
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4516<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4517<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4518<address>
4519 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
4520 src="http://jigsaw.w3.org/css-validator/images/vcss" alt="Valid CSS!"></a>
4521 <a href="http://validator.w3.org/check/referer"><img
4522 src="http://www.w3.org/Icons/valid-html401" alt="Valid HTML 4.01!" /></a>
4523
4524 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]4525 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]4526 Last modified: $Date$
4527</address>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4528</body>
4529</html>