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gerrit-public.fairphone.software / toolchain / llvm-project / 644f9173582f44b6293c7fadda5dc7e2bd5d5dfc / . / llvm / docs / LangRef.html
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5 <title>LLVM Assembly Language Reference Manual</title>
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7 <meta name="author" content="Chris Lattner">
8 <meta name="description"
9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]12
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]13<body>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]14
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]15<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]16<ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]17 <li><a href="#abstract">Abstract</a></li>
18 <li><a href="#introduction">Introduction</a></li>
19 <li><a href="#identifiers">Identifiers</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]20 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]24 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]25 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]26 <li><a href="#functionstructure">Functions</a></li>
Anton Korobeynikov546ea7e2007-04-29 18:02:48 +0000[diff] [blame]27 <li><a href="#aliasstructure">Aliases</a>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]28 <li><a href="#paramattrs">Parameter Attributes</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]29 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]30 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]31 </ol>
32 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]33 <li><a href="#typesystem">Type System</a>
34 <ol>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]35 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]36 <ol>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]37 <li><a href="#t_classifications">Type Classifications</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]38 </ol>
39 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]40 <li><a href="#t_derived">Derived Types</a>
41 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]42 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]43 <li><a href="#t_function">Function Type</a></li>
44 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]45 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]46 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]47 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]48 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]49 </ol>
50 </li>
51 </ol>
52 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]53 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]54 <ol>
55 <li><a href="#simpleconstants">Simple Constants</a>
56 <li><a href="#aggregateconstants">Aggregate Constants</a>
57 <li><a href="#globalconstants">Global Variable and Function Addresses</a>
58 <li><a href="#undefvalues">Undefined Values</a>
59 <li><a href="#constantexprs">Constant Expressions</a>
60 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]61 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]62 <li><a href="#othervalues">Other Values</a>
63 <ol>
64 <li><a href="#inlineasm">Inline Assembler Expressions</a>
65 </ol>
66 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]67 <li><a href="#instref">Instruction Reference</a>
68 <ol>
69 <li><a href="#terminators">Terminator Instructions</a>
70 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
72 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]73 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
74 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]75 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]76 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]77 </ol>
78 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]79 <li><a href="#binaryops">Binary Operations</a>
80 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]81 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
82 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
83 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]84 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
85 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
86 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]87 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
88 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
89 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]90 </ol>
91 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]92 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
93 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]94 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
95 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
96 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]97 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]98 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]99 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]100 </ol>
101 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]102 <li><a href="#vectorops">Vector Operations</a>
103 <ol>
104 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
105 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
106 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]109 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]110 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]111 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
112 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
113 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]114 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
115 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
116 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]117 </ol>
118 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]119 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]120 <ol>
121 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
122 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
123 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
124 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
125 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]126 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
127 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
128 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
129 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]130 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
131 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]132 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]133 </ol>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]134 <li><a href="#otherops">Other Operations</a>
135 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]136 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
137 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]138 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]139 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]140 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]141 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></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 Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]144 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]146 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]147 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]148 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
149 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]150 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
151 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
152 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]155 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
156 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]157 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
158 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
159 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]160 </ol>
161 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]162 <li><a href="#int_codegen">Code Generator Intrinsics</a>
163 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]164 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
165 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
166 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
167 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
168 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
169 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
170 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]171 </ol>
172 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]173 <li><a href="#int_libc">Standard C Library Intrinsics</a>
174 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]175 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
176 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
177 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
178 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
179 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]180 </ol>
181 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]182 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]183 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]184 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]185 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
186 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
187 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]188 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
189 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]190 </ol>
191 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]192 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]193 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]194 <li><a href="#int_atomics">Atomic Operations and Synchronization Intrinsics</a>
195 <ol>
196 <li><a href="#int_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_ls">'<tt>llvm.atomic.ls.*</tt>' Intrinsic</a></li>
198 <li><a href="#int_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_lss">'<tt>llvm.atomic.lss.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a></li>
201 </ol>
202 </li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame^]203 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
204 <ol>
205 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
206 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
207 </ol>
208 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]209 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]210 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]211 <li><a href="#int_var_annotation">
212 <tt>llvm.var.annotation</tt>' Intrinsic</a></li>
213 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]214 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]215 </ol>
216 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]217</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]218
219<div class="doc_author">
220 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
221 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]222</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]223
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]224<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]225<div class="doc_section"> <a name="abstract">Abstract </a></div>
226<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]227
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]228<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]229<p>This document is a reference manual for the LLVM assembly language.
230LLVM is an SSA based representation that provides type safety,
231low-level operations, flexibility, and the capability of representing
232'all' high-level languages cleanly. It is the common code
233representation used throughout all phases of the LLVM compilation
234strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]235</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]236
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]237<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]238<div class="doc_section"> <a name="introduction">Introduction</a> </div>
239<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]240
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]241<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]242
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]243<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]244different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]245representation (suitable for fast loading by a Just-In-Time compiler),
246and as a human readable assembly language representation. This allows
247LLVM to provide a powerful intermediate representation for efficient
248compiler transformations and analysis, while providing a natural means
249to debug and visualize the transformations. The three different forms
250of LLVM are all equivalent. This document describes the human readable
251representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]252
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]253<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]254while being expressive, typed, and extensible at the same time. It
255aims to be a "universal IR" of sorts, by being at a low enough level
256that high-level ideas may be cleanly mapped to it (similar to how
257microprocessors are "universal IR's", allowing many source languages to
258be mapped to them). By providing type information, LLVM can be used as
259the target of optimizations: for example, through pointer analysis, it
260can be proven that a C automatic variable is never accessed outside of
261the current function... allowing it to be promoted to a simple SSA
262value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]263
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]264</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]265
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]266<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]267<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
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>It is important to note that this document describes 'well formed'
272LLVM assembly language. There is a difference between what the parser
273accepts and what is considered 'well formed'. For example, the
274following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]275
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]276<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]277<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]278%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]279</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]280</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]281
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]282<p>...because the definition of <tt>%x</tt> does not dominate all of
283its uses. The LLVM infrastructure provides a verification pass that may
284be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]285automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]286the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]287by the verifier pass indicate bugs in transformation passes or input to
288the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]289</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]290
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]291<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]292
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]293<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]294<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]295<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]296
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]297<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]298
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]299<p>LLVM uses three different forms of identifiers, for different
300purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]301
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]302<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]303 <li>Named values are represented as a string of characters with a '%' prefix.
304 For example, %foo, %DivisionByZero, %a.really.long.identifier. The actual
305 regular expression used is '<tt>%[a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
306 Identifiers which require other characters in their names can be surrounded
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]307 with quotes. In this way, anything except a <tt>&quot;</tt> character can be used
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]308 in a name.</li>
309
310 <li>Unnamed values are represented as an unsigned numeric value with a '%'
311 prefix. For example, %12, %2, %44.</li>
312
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]313 <li>Constants, which are described in a <a href="#constants">section about
314 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]315</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]316
317<p>LLVM requires that values start with a '%' sign for two reasons: Compilers
318don't need to worry about name clashes with reserved words, and the set of
319reserved words may be expanded in the future without penalty. Additionally,
320unnamed identifiers allow a compiler to quickly come up with a temporary
321variable without having to avoid symbol table conflicts.</p>
322
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]323<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]324languages. There are keywords for different opcodes
325('<tt><a href="#i_add">add</a></tt>',
326 '<tt><a href="#i_bitcast">bitcast</a></tt>',
327 '<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]328href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]329and others. These reserved words cannot conflict with variable names, because
330none of them start with a '%' character.</p>
331
332<p>Here is an example of LLVM code to multiply the integer variable
333'<tt>%X</tt>' by 8:</p>
334
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]335<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]336
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]337<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]338<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]339%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]340</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]341</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]342
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]343<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]344
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]345<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]346<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]347%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]348</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]349</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]350
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]351<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]352
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]353<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]354<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]355<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
356<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
357%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]358</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]359</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]360
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]361<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
362important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]364<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]365
366 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
367 line.</li>
368
369 <li>Unnamed temporaries are created when the result of a computation is not
370 assigned to a named value.</li>
371
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]372 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]373
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]374</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]375
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]376<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]377demonstrating instructions, we will follow an instruction with a comment that
378defines the type and name of value produced. Comments are shown in italic
379text.</p>
380
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]381</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]382
383<!-- *********************************************************************** -->
384<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
385<!-- *********************************************************************** -->
386
387<!-- ======================================================================= -->
388<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
389</div>
390
391<div class="doc_text">
392
393<p>LLVM programs are composed of "Module"s, each of which is a
394translation unit of the input programs. Each module consists of
395functions, global variables, and symbol table entries. Modules may be
396combined together with the LLVM linker, which merges function (and
397global variable) definitions, resolves forward declarations, and merges
398symbol table entries. Here is an example of the "hello world" module:</p>
399
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]400<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]401<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]402<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
403 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]404
405<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]406<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]407
408<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]409define i32 @main() { <i>; i32()* </i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]410 <i>; Convert [13x i8 ]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]411 %cast210 = <a
Chris Lattner2150cde2007-06-12 17:01:15 +0000[diff] [blame]412 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]413
414 <i>; Call puts function to write out the string to stdout...</i>
415 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000[diff] [blame]416 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]417 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]418 href="#i_ret">ret</a> i32 0<br>}<br>
419</pre>
420</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]421
422<p>This example is made up of a <a href="#globalvars">global variable</a>
423named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
424function, and a <a href="#functionstructure">function definition</a>
425for "<tt>main</tt>".</p>
426
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]427<p>In general, a module is made up of a list of global values,
428where both functions and global variables are global values. Global values are
429represented by a pointer to a memory location (in this case, a pointer to an
430array of char, and a pointer to a function), and have one of the following <a
431href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]432
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]433</div>
434
435<!-- ======================================================================= -->
436<div class="doc_subsection">
437 <a name="linkage">Linkage Types</a>
438</div>
439
440<div class="doc_text">
441
442<p>
443All Global Variables and Functions have one of the following types of linkage:
444</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]445
446<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]447
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]448 <dt><tt><b><a name="linkage_internal">internal</a></b></tt> </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]449
450 <dd>Global values with internal linkage are only directly accessible by
451 objects in the current module. In particular, linking code into a module with
452 an internal global value may cause the internal to be renamed as necessary to
453 avoid collisions. Because the symbol is internal to the module, all
454 references can be updated. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]455 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]456 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]457
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]458 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]460 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
461 the same name when linkage occurs. This is typically used to implement
462 inline functions, templates, or other code which must be generated in each
463 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
464 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]465 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]466
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]467 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]468
469 <dd>"<tt>weak</tt>" linkage is exactly the same as <tt>linkonce</tt> linkage,
470 except that unreferenced <tt>weak</tt> globals may not be discarded. This is
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]471 used for globals that may be emitted in multiple translation units, but that
472 are not guaranteed to be emitted into every translation unit that uses them.
473 One example of this are common globals in C, such as "<tt>int X;</tt>" at
474 global scope.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]475 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]476
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]477 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]478
479 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
480 pointer to array type. When two global variables with appending linkage are
481 linked together, the two global arrays are appended together. This is the
482 LLVM, typesafe, equivalent of having the system linker append together
483 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]484 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]485
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]486 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
487 <dd>The semantics of this linkage follow the ELF model: the symbol is weak
488 until linked, if not linked, the symbol becomes null instead of being an
489 undefined reference.
490 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]491
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]492 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]493
494 <dd>If none of the above identifiers are used, the global is externally
495 visible, meaning that it participates in linkage and can be used to resolve
496 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]497 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]498</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]499
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]500 <p>
501 The next two types of linkage are targeted for Microsoft Windows platform
502 only. They are designed to support importing (exporting) symbols from (to)
503 DLLs.
504 </p>
505
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]506 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]507 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
508
509 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
510 or variable via a global pointer to a pointer that is set up by the DLL
511 exporting the symbol. On Microsoft Windows targets, the pointer name is
512 formed by combining <code>_imp__</code> and the function or variable name.
513 </dd>
514
515 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
516
517 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
518 pointer to a pointer in a DLL, so that it can be referenced with the
519 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
520 name is formed by combining <code>_imp__</code> and the function or variable
521 name.
522 </dd>
523
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]524</dl>
525
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]526<p><a name="linkage_external"></a>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]527variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
528variable and was linked with this one, one of the two would be renamed,
529preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
530external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000[diff] [blame]531outside of the current module.</p>
532<p>It is illegal for a function <i>declaration</i>
533to have any linkage type other than "externally visible", <tt>dllimport</tt>,
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]534or <tt>extern_weak</tt>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]535<p>Aliases can have only <tt>external</tt>, <tt>internal</tt> and <tt>weak</tt>
536linkages.
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]537</div>
538
539<!-- ======================================================================= -->
540<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]541 <a name="callingconv">Calling Conventions</a>
542</div>
543
544<div class="doc_text">
545
546<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
547and <a href="#i_invoke">invokes</a> can all have an optional calling convention
548specified for the call. The calling convention of any pair of dynamic
549caller/callee must match, or the behavior of the program is undefined. The
550following calling conventions are supported by LLVM, and more may be added in
551the future:</p>
552
553<dl>
554 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
555
556 <dd>This calling convention (the default if no other calling convention is
557 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]558 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000[diff] [blame]559 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]560 </dd>
561
562 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
563
564 <dd>This calling convention attempts to make calls as fast as possible
565 (e.g. by passing things in registers). This calling convention allows the
566 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattnerc792eb32005-05-06 23:08:23 +0000[diff] [blame]567 without having to conform to an externally specified ABI. Implementations of
568 this convention should allow arbitrary tail call optimization to be supported.
569 This calling convention does not support varargs and requires the prototype of
570 all callees to exactly match the prototype of the function definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]571 </dd>
572
573 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
574
575 <dd>This calling convention attempts to make code in the caller as efficient
576 as possible under the assumption that the call is not commonly executed. As
577 such, these calls often preserve all registers so that the call does not break
578 any live ranges in the caller side. This calling convention does not support
579 varargs and requires the prototype of all callees to exactly match the
580 prototype of the function definition.
581 </dd>
582
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]583 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]584
585 <dd>Any calling convention may be specified by number, allowing
586 target-specific calling conventions to be used. Target specific calling
587 conventions start at 64.
588 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]589</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]590
591<p>More calling conventions can be added/defined on an as-needed basis, to
592support pascal conventions or any other well-known target-independent
593convention.</p>
594
595</div>
596
597<!-- ======================================================================= -->
598<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]599 <a name="visibility">Visibility Styles</a>
600</div>
601
602<div class="doc_text">
603
604<p>
605All Global Variables and Functions have one of the following visibility styles:
606</p>
607
608<dl>
609 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
610
611 <dd>On ELF, default visibility means that the declaration is visible to other
612 modules and, in shared libraries, means that the declared entity may be
613 overridden. On Darwin, default visibility means that the declaration is
614 visible to other modules. Default visibility corresponds to "external
615 linkage" in the language.
616 </dd>
617
618 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
619
620 <dd>Two declarations of an object with hidden visibility refer to the same
621 object if they are in the same shared object. Usually, hidden visibility
622 indicates that the symbol will not be placed into the dynamic symbol table,
623 so no other module (executable or shared library) can reference it
624 directly.
625 </dd>
626
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]627 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
628
629 <dd>On ELF, protected visibility indicates that the symbol will be placed in
630 the dynamic symbol table, but that references within the defining module will
631 bind to the local symbol. That is, the symbol cannot be overridden by another
632 module.
633 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]634</dl>
635
636</div>
637
638<!-- ======================================================================= -->
639<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]640 <a name="globalvars">Global Variables</a>
641</div>
642
643<div class="doc_text">
644
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]645<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]646instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]647an explicit section to be placed in, and may have an optional explicit alignment
648specified. A variable may be defined as "thread_local", which means that it
649will not be shared by threads (each thread will have a separated copy of the
650variable). A variable may be defined as a global "constant," which indicates
651that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]652optimization, allowing the global data to be placed in the read-only section of
653an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]654cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]655
656<p>
657LLVM explicitly allows <em>declarations</em> of global variables to be marked
658constant, even if the final definition of the global is not. This capability
659can be used to enable slightly better optimization of the program, but requires
660the language definition to guarantee that optimizations based on the
661'constantness' are valid for the translation units that do not include the
662definition.
663</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]664
665<p>As SSA values, global variables define pointer values that are in
666scope (i.e. they dominate) all basic blocks in the program. Global
667variables always define a pointer to their "content" type because they
668describe a region of memory, and all memory objects in LLVM are
669accessed through pointers.</p>
670
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]671<p>LLVM allows an explicit section to be specified for globals. If the target
672supports it, it will emit globals to the section specified.</p>
673
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]674<p>An explicit alignment may be specified for a global. If not present, or if
675the alignment is set to zero, the alignment of the global is set by the target
676to whatever it feels convenient. If an explicit alignment is specified, the
677global is forced to have at least that much alignment. All alignments must be
678a power of 2.</p>
679
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]680<p>For example, the following defines a global with an initializer, section,
681 and alignment:</p>
682
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]683<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]684<pre>
Chris Lattner0a2d0992007-07-13 20:01:46 +0000[diff] [blame]685@G = constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]686</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]687</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]688
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]689</div>
690
691
692<!-- ======================================================================= -->
693<div class="doc_subsection">
694 <a name="functionstructure">Functions</a>
695</div>
696
697<div class="doc_text">
698
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]699<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
700an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]701<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]702<a href="#callingconv">calling convention</a>, a return type, an optional
703<a href="#paramattrs">parameter attribute</a> for the return type, a function
704name, a (possibly empty) argument list (each with optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]705<a href="#paramattrs">parameter attributes</a>), an optional section, an
706optional alignment, an opening curly brace, a list of basic blocks, and a
707closing curly brace.
708
709LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
710optional <a href="#linkage">linkage type</a>, an optional
711<a href="#visibility">visibility style</a>, an optional
712<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]713<a href="#paramattrs">parameter attribute</a> for the return type, a function
714name, a possibly empty list of arguments, and an optional alignment.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]715
716<p>A function definition contains a list of basic blocks, forming the CFG for
717the function. Each basic block may optionally start with a label (giving the
718basic block a symbol table entry), contains a list of instructions, and ends
719with a <a href="#terminators">terminator</a> instruction (such as a branch or
720function return).</p>
721
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]722<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]723executed on entrance to the function, and it is not allowed to have predecessor
724basic blocks (i.e. there can not be any branches to the entry block of a
725function). Because the block can have no predecessors, it also cannot have any
726<a href="#i_phi">PHI nodes</a>.</p>
727
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]728<p>LLVM allows an explicit section to be specified for functions. If the target
729supports it, it will emit functions to the section specified.</p>
730
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]731<p>An explicit alignment may be specified for a function. If not present, or if
732the alignment is set to zero, the alignment of the function is set by the target
733to whatever it feels convenient. If an explicit alignment is specified, the
734function is forced to have at least that much alignment. All alignments must be
735a power of 2.</p>
736
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]737</div>
738
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]739
740<!-- ======================================================================= -->
741<div class="doc_subsection">
742 <a name="aliasstructure">Aliases</a>
743</div>
744<div class="doc_text">
745 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikovb18f8f82007-04-28 13:45:00 +0000[diff] [blame]746 function or global variable or bitcast of global value). Aliases may have an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]747 optional <a href="#linkage">linkage type</a>, and an
748 optional <a href="#visibility">visibility style</a>.</p>
749
750 <h5>Syntax:</h5>
751
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]752<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]753<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]754@&lt;Name&gt; = [Linkage] [Visibility] alias &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]755</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]756</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]757
758</div>
759
760
761
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]762<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]763<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
764<div class="doc_text">
765 <p>The return type and each parameter of a function type may have a set of
766 <i>parameter attributes</i> associated with them. Parameter attributes are
767 used to communicate additional information about the result or parameters of
768 a function. Parameter attributes are considered to be part of the function
769 type so two functions types that differ only by the parameter attributes
770 are different function types.</p>
771
Reid Spencercf7ebf52007-01-15 18:27:39 +0000[diff] [blame]772 <p>Parameter attributes are simple keywords that follow the type specified. If
773 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]774 example:</p>
775
776<div class="doc_code">
777<pre>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]778%someFunc = i16 (i8 signext %someParam) zeroext
779%someFunc = i16 (i8 zeroext %someParam) zeroext
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]780</pre>
781</div>
782
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]783 <p>Note that the two function types above are unique because the parameter has
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]784 a different attribute (<tt>signext</tt> in the first one, <tt>zeroext</tt> in
785 the second). Also note that the attribute for the function result
786 (<tt>zeroext</tt>) comes immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]787
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]788 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]789 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]790 <dt><tt>zeroext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]791 <dd>This indicates that the parameter should be zero extended just before
792 a call to this function.</dd>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]793 <dt><tt>signext</tt></dt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]794 <dd>This indicates that the parameter should be sign extended just before
795 a call to this function.</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]796 <dt><tt>inreg</tt></dt>
797 <dd>This indicates that the parameter should be placed in register (if
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]798 possible) during assembling function call. Support for this attribute is
799 target-specific</dd>
Anton Korobeynikove8166852007-01-28 14:30:45 +0000[diff] [blame]800 <dt><tt>sret</tt></dt>
Anton Korobeynikove93c6e82007-01-28 15:27:21 +0000[diff] [blame]801 <dd>This indicates that the parameter specifies the address of a structure
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]802 that is the return value of the function in the source program.</dd>
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000[diff] [blame]803 <dt><tt>noalias</tt></dt>
804 <dd>This indicates that the parameter not alias any other object or any
805 other "noalias" objects during the function call.
Reid Spencer9d1700e2007-03-22 02:18:56 +0000[diff] [blame]806 <dt><tt>noreturn</tt></dt>
807 <dd>This function attribute indicates that the function never returns. This
808 indicates to LLVM that every call to this function should be treated as if
809 an <tt>unreachable</tt> instruction immediately followed the call.</dd>
Reid Spencer05dbb9d2007-03-22 02:02:11 +0000[diff] [blame]810 <dt><tt>nounwind</tt></dt>
811 <dd>This function attribute indicates that the function type does not use
812 the unwind instruction and does not allow stack unwinding to propagate
813 through it.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]814 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]815
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]816</div>
817
818<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]819<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]820 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]821</div>
822
823<div class="doc_text">
824<p>
825Modules may contain "module-level inline asm" blocks, which corresponds to the
826GCC "file scope inline asm" blocks. These blocks are internally concatenated by
827LLVM and treated as a single unit, but may be separated in the .ll file if
828desired. The syntax is very simple:
829</p>
830
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]831<div class="doc_code">
832<pre>
833module asm "inline asm code goes here"
834module asm "more can go here"
835</pre>
836</div>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]837
838<p>The strings can contain any character by escaping non-printable characters.
839 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
840 for the number.
841</p>
842
843<p>
844 The inline asm code is simply printed to the machine code .s file when
845 assembly code is generated.
846</p>
847</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]848
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]849<!-- ======================================================================= -->
850<div class="doc_subsection">
851 <a name="datalayout">Data Layout</a>
852</div>
853
854<div class="doc_text">
855<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]856data is to be laid out in memory. The syntax for the data layout is simply:</p>
857<pre> target datalayout = "<i>layout specification</i>"</pre>
858<p>The <i>layout specification</i> consists of a list of specifications
859separated by the minus sign character ('-'). Each specification starts with a
860letter and may include other information after the letter to define some
861aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]862<dl>
863 <dt><tt>E</tt></dt>
864 <dd>Specifies that the target lays out data in big-endian form. That is, the
865 bits with the most significance have the lowest address location.</dd>
866 <dt><tt>e</tt></dt>
867 <dd>Specifies that hte target lays out data in little-endian form. That is,
868 the bits with the least significance have the lowest address location.</dd>
869 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
870 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
871 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
872 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
873 too.</dd>
874 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
875 <dd>This specifies the alignment for an integer type of a given bit
876 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
877 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
878 <dd>This specifies the alignment for a vector type of a given bit
879 <i>size</i>.</dd>
880 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
881 <dd>This specifies the alignment for a floating point type of a given bit
882 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
883 (double).</dd>
884 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
885 <dd>This specifies the alignment for an aggregate type of a given bit
886 <i>size</i>.</dd>
887</dl>
888<p>When constructing the data layout for a given target, LLVM starts with a
889default set of specifications which are then (possibly) overriden by the
890specifications in the <tt>datalayout</tt> keyword. The default specifications
891are given in this list:</p>
892<ul>
893 <li><tt>E</tt> - big endian</li>
894 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
895 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
896 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
897 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
898 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
899 <li><tt>i64:32:64</tt> - i64 has abi alignment of 32-bits but preferred
900 alignment of 64-bits</li>
901 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
902 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
903 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
904 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
905 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
906</ul>
907<p>When llvm is determining the alignment for a given type, it uses the
908following rules:
909<ol>
910 <li>If the type sought is an exact match for one of the specifications, that
911 specification is used.</li>
912 <li>If no match is found, and the type sought is an integer type, then the
913 smallest integer type that is larger than the bitwidth of the sought type is
914 used. If none of the specifications are larger than the bitwidth then the the
915 largest integer type is used. For example, given the default specifications
916 above, the i7 type will use the alignment of i8 (next largest) while both
917 i65 and i256 will use the alignment of i64 (largest specified).</li>
918 <li>If no match is found, and the type sought is a vector type, then the
919 largest vector type that is smaller than the sought vector type will be used
920 as a fall back. This happens because <128 x double> can be implemented in
921 terms of 64 <2 x double>, for example.</li>
922</ol>
923</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]924
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]925<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]926<div class="doc_section"> <a name="typesystem">Type System</a> </div>
927<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]928
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]929<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]930
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]931<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]932intermediate representation. Being typed enables a number of
933optimizations to be performed on the IR directly, without having to do
934extra analyses on the side before the transformation. A strong type
935system makes it easier to read the generated code and enables novel
936analyses and transformations that are not feasible to perform on normal
937three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]938
939</div>
940
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]941<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]942<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]943<div class="doc_text">
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]944<p>The primitive types are the fundamental building blocks of the LLVM
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]945system. The current set of primitive types is as follows:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]946
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]947<table class="layout">
948 <tr class="layout">
949 <td class="left">
950 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]951 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]952 <tr><th>Type</th><th>Description</th></tr>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]953 <tr><td><tt><a name="t_void">void</a></tt></td><td>No value</td></tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]954 <tr><td><tt>label</tt></td><td>Branch destination</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]955 </tbody>
956 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]957 </td>
958 <td class="right">
959 <table>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]960 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]961 <tr><th>Type</th><th>Description</th></tr>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]962 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]963 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]964 </tbody>
965 </table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]966 </td>
967 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]968</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]969</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]970
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]971<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]972<div class="doc_subsubsection"> <a name="t_classifications">Type
973Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]974<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]975<p>These different primitive types fall into a few useful
976classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]977
978<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]979 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]980 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]981 <tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]982 <td><a name="t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]983 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]984 </tr>
985 <tr>
986 <td><a name="t_floating">floating point</a></td>
987 <td><tt>float, double</tt></td>
988 </tr>
989 <tr>
990 <td><a name="t_firstclass">first class</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]991 <td><tt>i1, ..., float, double, <br/>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]992 <a href="#t_pointer">pointer</a>,<a href="#t_vector">vector</a></tt>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]993 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]994 </tr>
995 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]996</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]997
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]998<p>The <a href="#t_firstclass">first class</a> types are perhaps the
999most important. Values of these types are the only ones which can be
1000produced by instructions, passed as arguments, or used as operands to
1001instructions. This means that all structures and arrays must be
1002manipulated either by pointer or by component.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1003</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1004
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1005<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1006<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1007
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1008<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1009
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1010<p>The real power in LLVM comes from the derived types in the system.
1011This is what allows a programmer to represent arrays, functions,
1012pointers, and other useful types. Note that these derived types may be
1013recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1014
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1015</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1016
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1017<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1018<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1019
1020<div class="doc_text">
1021
1022<h5>Overview:</h5>
1023<p>The integer type is a very simple derived type that simply specifies an
1024arbitrary bit width for the integer type desired. Any bit width from 1 bit to
10252^23-1 (about 8 million) can be specified.</p>
1026
1027<h5>Syntax:</h5>
1028
1029<pre>
1030 iN
1031</pre>
1032
1033<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1034value.</p>
1035
1036<h5>Examples:</h5>
1037<table class="layout">
1038 <tr class="layout">
1039 <td class="left">
1040 <tt>i1</tt><br/>
1041 <tt>i4</tt><br/>
1042 <tt>i8</tt><br/>
1043 <tt>i16</tt><br/>
1044 <tt>i32</tt><br/>
1045 <tt>i42</tt><br/>
1046 <tt>i64</tt><br/>
1047 <tt>i1942652</tt><br/>
1048 </td>
1049 <td class="left">
1050 A boolean integer of 1 bit<br/>
1051 A nibble sized integer of 4 bits.<br/>
1052 A byte sized integer of 8 bits.<br/>
1053 A half word sized integer of 16 bits.<br/>
1054 A word sized integer of 32 bits.<br/>
1055 An integer whose bit width is the answer. <br/>
1056 A double word sized integer of 64 bits.<br/>
1057 A really big integer of over 1 million bits.<br/>
1058 </td>
1059 </tr>
1060</table>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1061</div>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1062
1063<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1064<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1065
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1066<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1067
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1068<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1069
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1070<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1071sequentially in memory. The array type requires a size (number of
1072elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1073
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1074<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1075
1076<pre>
1077 [&lt;# elements&gt; x &lt;elementtype&gt;]
1078</pre>
1079
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1080<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1081be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1082
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1083<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1084<table class="layout">
1085 <tr class="layout">
1086 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1087 <tt>[40 x i32 ]</tt><br/>
1088 <tt>[41 x i32 ]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1089 <tt>[40 x i8]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1090 </td>
1091 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1092 Array of 40 32-bit integer values.<br/>
1093 Array of 41 32-bit integer values.<br/>
1094 Array of 40 8-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1095 </td>
1096 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1097</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1098<p>Here are some examples of multidimensional arrays:</p>
1099<table class="layout">
1100 <tr class="layout">
1101 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1102 <tt>[3 x [4 x i32]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1103 <tt>[12 x [10 x float]]</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1104 <tt>[2 x [3 x [4 x i16]]]</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1105 </td>
1106 <td class="left">
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1107 3x4 array of 32-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1108 12x10 array of single precision floating point values.<br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1109 2x3x4 array of 16-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1110 </td>
1111 </tr>
1112</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1113
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1114<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1115length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1116LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1117As a special case, however, zero length arrays are recognized to be variable
1118length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1119type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1120
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1121</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1122
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1123<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1124<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1125<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1126<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1127<p>The function type can be thought of as a function signature. It
1128consists of a return type and a list of formal parameter types.
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1129Function types are usually used to build virtual function tables
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1130(which are structures of pointers to functions), for indirect function
1131calls, and when defining a function.</p>
John Criswella0d50d22003-11-25 21:45:46 +0000[diff] [blame]1132<p>
1133The return type of a function type cannot be an aggregate type.
1134</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1135<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1136<pre> &lt;returntype&gt; (&lt;parameter list&gt;)<br></pre>
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]1137<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]1138specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1139which indicates that the function takes a variable number of arguments.
1140Variable argument functions can access their arguments with the <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1141 href="#int_varargs">variable argument handling intrinsic</a> functions.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1142<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1143<table class="layout">
1144 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1145 <td class="left"><tt>i32 (i32)</tt></td>
1146 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1147 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1148 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +0000[diff] [blame]1149 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]1150 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1151 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1152 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1153 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1154 <tt>float</tt>.
1155 </td>
1156 </tr><tr class="layout">
1157 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1158 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1159 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]1160 which returns an integer. This is the signature for <tt>printf</tt> in
1161 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1162 </td>
1163 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1164</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1165
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1166</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1167<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1168<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1169<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1170<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1171<p>The structure type is used to represent a collection of data members
1172together in memory. The packing of the field types is defined to match
1173the ABI of the underlying processor. The elements of a structure may
1174be any type that has a size.</p>
1175<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1176and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1177field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1178instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1179<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1180<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1181<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1182<table class="layout">
1183 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1184 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1185 <td class="left">A triple of three <tt>i32</tt> values</td>
1186 </tr><tr class="layout">
1187 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1188 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1189 second element is a <a href="#t_pointer">pointer</a> to a
1190 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1191 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1192 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1193</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1194</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1195
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1196<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1197<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1198</div>
1199<div class="doc_text">
1200<h5>Overview:</h5>
1201<p>The packed structure type is used to represent a collection of data members
1202together in memory. There is no padding between fields. Further, the alignment
1203of a packed structure is 1 byte. The elements of a packed structure may
1204be any type that has a size.</p>
1205<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1206and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1207field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1208instruction.</p>
1209<h5>Syntax:</h5>
1210<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1211<h5>Examples:</h5>
1212<table class="layout">
1213 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1214 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1215 <td class="left">A triple of three <tt>i32</tt> values</td>
1216 </tr><tr class="layout">
1217 <td class="left"><tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}&nbsp;&gt;</tt></td>
1218 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1219 second element is a <a href="#t_pointer">pointer</a> to a
1220 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1221 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]1222 </tr>
1223</table>
1224</div>
1225
1226<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1227<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1228<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1229<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1230<p>As in many languages, the pointer type represents a pointer or
1231reference to another object, which must live in memory.</p>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1232<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1233<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1234<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1235<table class="layout">
1236 <tr class="layout">
1237 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1238 <tt>[4x i32]*</tt><br/>
1239 <tt>i32 (i32 *) *</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1240 </td>
1241 <td class="left">
1242 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]1243 four <tt>i32</tt> values<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1244 A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1245 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
1246 <tt>i32</tt>.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1247 </td>
1248 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1249</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1250</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1251
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1252<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1253<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1254<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1255
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1256<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1257
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1258<p>A vector type is a simple derived type that represents a vector
1259of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1260are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1261A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +0000[diff] [blame]1262elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1263of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1264considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1265
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1266<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1267
1268<pre>
1269 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1270</pre>
1271
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1272<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1273be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1274
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1275<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1276
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1277<table class="layout">
1278 <tr class="layout">
1279 <td class="left">
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1280 <tt>&lt;4 x i32&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1281 <tt>&lt;8 x float&gt;</tt><br/>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1282 <tt>&lt;2 x i64&gt;</tt><br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1283 </td>
1284 <td class="left">
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1285 Vector of 4 32-bit integer values.<br/>
1286 Vector of 8 floating-point values.<br/>
1287 Vector of 2 64-bit integer values.<br/>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1288 </td>
1289 </tr>
1290</table>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1291</div>
1292
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]1293<!-- _______________________________________________________________________ -->
1294<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1295<div class="doc_text">
1296
1297<h5>Overview:</h5>
1298
1299<p>Opaque types are used to represent unknown types in the system. This
1300corresponds (for example) to the C notion of a foward declared structure type.
1301In LLVM, opaque types can eventually be resolved to any type (not just a
1302structure type).</p>
1303
1304<h5>Syntax:</h5>
1305
1306<pre>
1307 opaque
1308</pre>
1309
1310<h5>Examples:</h5>
1311
1312<table class="layout">
1313 <tr class="layout">
1314 <td class="left">
1315 <tt>opaque</tt>
1316 </td>
1317 <td class="left">
1318 An opaque type.<br/>
1319 </td>
1320 </tr>
1321</table>
1322</div>
1323
1324
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1325<!-- *********************************************************************** -->
1326<div class="doc_section"> <a name="constants">Constants</a> </div>
1327<!-- *********************************************************************** -->
1328
1329<div class="doc_text">
1330
1331<p>LLVM has several different basic types of constants. This section describes
1332them all and their syntax.</p>
1333
1334</div>
1335
1336<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1337<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1338
1339<div class="doc_text">
1340
1341<dl>
1342 <dt><b>Boolean constants</b></dt>
1343
1344 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1345 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1346 </dd>
1347
1348 <dt><b>Integer constants</b></dt>
1349
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1350 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]1351 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1352 integer types.
1353 </dd>
1354
1355 <dt><b>Floating point constants</b></dt>
1356
1357 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1358 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1359 notation (see below). Floating point constants must have a <a
1360 href="#t_floating">floating point</a> type. </dd>
1361
1362 <dt><b>Null pointer constants</b></dt>
1363
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1364 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1365 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1366
1367</dl>
1368
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1369<p>The one non-intuitive notation for constants is the optional hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1370of floating point constants. For example, the form '<tt>double
13710x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
13724.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]1373(and the only time that they are generated by the disassembler) is when a
1374floating point constant must be emitted but it cannot be represented as a
1375decimal floating point number. For example, NaN's, infinities, and other
1376special values are represented in their IEEE hexadecimal format so that
1377assembly and disassembly do not cause any bits to change in the constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1378
1379</div>
1380
1381<!-- ======================================================================= -->
1382<div class="doc_subsection"><a name="aggregateconstants">Aggregate Constants</a>
1383</div>
1384
1385<div class="doc_text">
Chris Lattner455fc8c2005-03-07 22:13:59 +0000[diff] [blame]1386<p>Aggregate constants arise from aggregation of simple constants
1387and smaller aggregate constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1388
1389<dl>
1390 <dt><b>Structure constants</b></dt>
1391
1392 <dd>Structure constants are represented with notation similar to structure
1393 type definitions (a comma separated list of elements, surrounded by braces
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1394 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* %G }</tt>",
Chris Lattner0a2d0992007-07-13 20:01:46 +0000[diff] [blame]1395 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]1396 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1397 types of elements must match those specified by the type.
1398 </dd>
1399
1400 <dt><b>Array constants</b></dt>
1401
1402 <dd>Array constants are represented with notation similar to array type
1403 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1404 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1405 constants must have <a href="#t_array">array type</a>, and the number and
1406 types of elements must match those specified by the type.
1407 </dd>
1408
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1409 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1410
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1411 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1412 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1413 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1414 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1415 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1416 match those specified by the type.
1417 </dd>
1418
1419 <dt><b>Zero initialization</b></dt>
1420
1421 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1422 value to zero of <em>any</em> type, including scalar and aggregate types.
1423 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]1424 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1425 initializers.
1426 </dd>
1427</dl>
1428
1429</div>
1430
1431<!-- ======================================================================= -->
1432<div class="doc_subsection">
1433 <a name="globalconstants">Global Variable and Function Addresses</a>
1434</div>
1435
1436<div class="doc_text">
1437
1438<p>The addresses of <a href="#globalvars">global variables</a> and <a
1439href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1440constants. These constants are explicitly referenced when the <a
1441href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1442href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1443file:</p>
1444
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1445<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1446<pre>
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]1447@X = global i32 17
1448@Y = global i32 42
1449@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1450</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1451</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1452
1453</div>
1454
1455<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1456<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1457<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1458 <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]1459 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1460 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1461
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1462 <p>Undefined values indicate to the compiler that the program is well defined
1463 no matter what value is used, giving the compiler more freedom to optimize.
1464 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1465</div>
1466
1467<!-- ======================================================================= -->
1468<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1469</div>
1470
1471<div class="doc_text">
1472
1473<p>Constant expressions are used to allow expressions involving other constants
1474to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1475href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1476that does not have side effects (e.g. load and call are not supported). The
1477following is the syntax for constant expressions:</p>
1478
1479<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1480 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1481 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1482 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1483
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1484 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1485 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1486 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1487
1488 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1489 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]1490 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1491
1492 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1493 <dd>Truncate a floating point constant to another floating point type. The
1494 size of CST must be larger than the size of TYPE. Both types must be
1495 floating point.</dd>
1496
1497 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1498 <dd>Floating point extend a constant to another type. The size of CST must be
1499 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1500
1501 <dt><b><tt>fp2uint ( CST to TYPE )</tt></b></dt>
1502 <dd>Convert a floating point constant to the corresponding unsigned integer
1503 constant. TYPE must be an integer type. CST must be floating point. If the
1504 value won't fit in the integer type, the results are undefined.</dd>
1505
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1506 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1507 <dd>Convert a floating point constant to the corresponding signed integer
1508 constant. TYPE must be an integer type. CST must be floating point. If the
1509 value won't fit in the integer type, the results are undefined.</dd>
1510
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1511 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1512 <dd>Convert an unsigned integer constant to the corresponding floating point
1513 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]1514 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1515
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]1516 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1517 <dd>Convert a signed integer constant to the corresponding floating point
1518 constant. TYPE must be floating point. CST must be of integer type. If the
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]1519 value won't fit in the floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1520
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1521 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1522 <dd>Convert a pointer typed constant to the corresponding integer constant
1523 TYPE must be an integer type. CST must be of pointer type. The CST value is
1524 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1525
1526 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1527 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1528 pointer type. CST must be of integer type. The CST value is zero extended,
1529 truncated, or unchanged to make it fit in a pointer size. This one is
1530 <i>really</i> dangerous!</dd>
1531
1532 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1533 <dd>Convert a constant, CST, to another TYPE. The size of CST and TYPE must be
1534 identical (same number of bits). The conversion is done as if the CST value
1535 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]1536 with this operator, just the type. This can be used for conversion of
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1537 vector types to any other type, as long as they have the same bit width. For
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]1538 pointers it is only valid to cast to another pointer type.
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]1539 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1540
1541 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1542
1543 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1544 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1545 instruction, the index list may have zero or more indexes, which are required
1546 to make sense for the type of "CSTPTR".</dd>
1547
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1548 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1549
1550 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1551 constants.</dd>
1552
1553 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
1554 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
1555
1556 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
1557 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]1558
1559 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
1560
1561 <dd>Perform the <a href="#i_extractelement">extractelement
1562 operation</a> on constants.
1563
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1564 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
1565
1566 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1567 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]1568
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1569
1570 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
1571
1572 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]1573 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]1574
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1575 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
1576
Reid Spencer641f5c92004-12-09 18:13:12 +0000[diff] [blame]1577 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
1578 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1579 binary</a> operations. The constraints on operands are the same as those for
1580 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1581 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1582</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1583</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]1584
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1585<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1586<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
1587<!-- *********************************************************************** -->
1588
1589<!-- ======================================================================= -->
1590<div class="doc_subsection">
1591<a name="inlineasm">Inline Assembler Expressions</a>
1592</div>
1593
1594<div class="doc_text">
1595
1596<p>
1597LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
1598Module-Level Inline Assembly</a>) through the use of a special value. This
1599value represents the inline assembler as a string (containing the instructions
1600to emit), a list of operand constraints (stored as a string), and a flag that
1601indicates whether or not the inline asm expression has side effects. An example
1602inline assembler expression is:
1603</p>
1604
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1605<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1606<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1607i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1608</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1609</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1610
1611<p>
1612Inline assembler expressions may <b>only</b> be used as the callee operand of
1613a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
1614</p>
1615
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1616<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1617<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1618%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1619</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1620</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1621
1622<p>
1623Inline asms with side effects not visible in the constraint list must be marked
1624as having side effects. This is done through the use of the
1625'<tt>sideeffect</tt>' keyword, like so:
1626</p>
1627
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1628<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1629<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1630call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1631</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1632</div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]1633
1634<p>TODO: The format of the asm and constraints string still need to be
1635documented here. Constraints on what can be done (e.g. duplication, moving, etc
1636need to be documented).
1637</p>
1638
1639</div>
1640
1641<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1642<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
1643<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1644
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1645<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1646
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1647<p>The LLVM instruction set consists of several different
1648classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1649instructions</a>, <a href="#binaryops">binary instructions</a>,
1650<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1651 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
1652instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1653
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1654</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1655
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1656<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1657<div class="doc_subsection"> <a name="terminators">Terminator
1658Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1659
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1660<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1661
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1662<p>As mentioned <a href="#functionstructure">previously</a>, every
1663basic block in a program ends with a "Terminator" instruction, which
1664indicates which block should be executed after the current block is
1665finished. These terminator instructions typically yield a '<tt>void</tt>'
1666value: they produce control flow, not values (the one exception being
1667the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1668<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1669 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
1670instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1671the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
1672 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
1673 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1674
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1675</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1676
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1677<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1678<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
1679Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1680<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1681<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1682<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]1683 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1684</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1685<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1686<p>The '<tt>ret</tt>' instruction is used to return control flow (and a
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]1687value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +0000[diff] [blame]1688<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1689returns a value and then causes control flow, and one that just causes
1690control flow to occur.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1691<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1692<p>The '<tt>ret</tt>' instruction may return any '<a
1693 href="#t_firstclass">first class</a>' type. Notice that a function is
1694not <a href="#wellformed">well formed</a> if there exists a '<tt>ret</tt>'
1695instruction inside of the function that returns a value that does not
1696match the return type of the function.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1697<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1698<p>When the '<tt>ret</tt>' instruction is executed, control flow
1699returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +0000[diff] [blame]1700 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1701the instruction after the call. If the caller was an "<a
1702 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1703at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1704returns a value, that value shall set the call or invoke instruction's
1705return value.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1706<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1707<pre> ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1708 ret void <i>; Return from a void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1709</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1710</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1711<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1712<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1713<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1714<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1715<pre> br i1 &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]1716</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1717<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1718<p>The '<tt>br</tt>' instruction is used to cause control flow to
1719transfer to a different basic block in the current function. There are
1720two forms of this instruction, corresponding to a conditional branch
1721and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1722<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1723<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1724single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1725unconditional form of the '<tt>br</tt>' instruction takes a single
1726'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1727<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1728<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1729argument is evaluated. If the value is <tt>true</tt>, control flows
1730to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
1731control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1732<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1733<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1734 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]1735</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1736<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1737<div class="doc_subsubsection">
1738 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
1739</div>
1740
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1741<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1742<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1743
1744<pre>
1745 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
1746</pre>
1747
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1748<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1749
1750<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
1751several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1752instruction, allowing a branch to occur to one of many possible
1753destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1754
1755
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1756<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1757
1758<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
1759comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
1760an array of pairs of comparison value constants and '<tt>label</tt>'s. The
1761table is not allowed to contain duplicate constant entries.</p>
1762
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1763<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1764
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1765<p>The <tt>switch</tt> instruction specifies a table of values and
1766destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1767table is searched for the given value. If the value is found, control flow is
1768transfered to the corresponding destination; otherwise, control flow is
1769transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1770
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1771<h5>Implementation:</h5>
1772
1773<p>Depending on properties of the target machine and the particular
1774<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +0000[diff] [blame]1775ways. For example, it could be generated as a series of chained conditional
1776branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1777
1778<h5>Example:</h5>
1779
1780<pre>
1781 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]1782 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1783 switch i32 %Val, label %truedest [i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1784
1785 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1786 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]1787
1788 <i>; Implement a jump table:</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1789 switch i32 %val, label %otherwise [ i32 0, label %onzero
1790 i32 1, label %onone
1791 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1792</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1793</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1794
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1795<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1796<div class="doc_subsubsection">
1797 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
1798</div>
1799
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1800<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1801
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1802<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1803
1804<pre>
1805 &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]1806 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1807</pre>
1808
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]1809<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1810
1811<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
1812function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1813'<tt>normal</tt>' label or the
1814'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1815"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
1816"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +0000[diff] [blame]1817href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
1818continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1819
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1820<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1821
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1822<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1823
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1824<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1825 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]1826 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1827 convention</a> the call should use. If none is specified, the call defaults
1828 to using C calling conventions.
1829 </li>
1830 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
1831 function value being invoked. In most cases, this is a direct function
1832 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
1833 an arbitrary pointer to function value.
1834 </li>
1835
1836 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
1837 function to be invoked. </li>
1838
1839 <li>'<tt>function args</tt>': argument list whose types match the function
1840 signature argument types. If the function signature indicates the function
1841 accepts a variable number of arguments, the extra arguments can be
1842 specified. </li>
1843
1844 <li>'<tt>normal label</tt>': the label reached when the called function
1845 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
1846
1847 <li>'<tt>exception label</tt>': the label reached when a callee returns with
1848 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
1849
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1850</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1851
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1852<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1853
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1854<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1855href="#i_call">call</a></tt>' instruction in most regards. The primary
1856difference is that it establishes an association with a label, which is used by
1857the runtime library to unwind the stack.</p>
1858
1859<p>This instruction is used in languages with destructors to ensure that proper
1860cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
1861exception. Additionally, this is important for implementation of
1862'<tt>catch</tt>' clauses in high-level languages that support them.</p>
1863
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1864<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]1865<pre>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]1866 %retval = invoke i32 %Test(i32 15) to label %Continue
1867 unwind label %TestCleanup <i>; {i32}:retval set</i>
1868 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Test(i32 15) to label %Continue
1869 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1870</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1871</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1872
1873
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1874<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1875
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1876<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
1877Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1878
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1879<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1880
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1881<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1882<pre>
1883 unwind
1884</pre>
1885
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1886<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1887
1888<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
1889at the first callee in the dynamic call stack which used an <a
1890href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
1891primarily used to implement exception handling.</p>
1892
Chris Lattner5ed60612003-09-03 00:41:47 +0000[diff] [blame]1893<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1894
1895<p>The '<tt>unwind</tt>' intrinsic causes execution of the current function to
1896immediately halt. The dynamic call stack is then searched for the first <a
1897href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
1898execution continues at the "exceptional" destination block specified by the
1899<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
1900dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1901</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]1902
1903<!-- _______________________________________________________________________ -->
1904
1905<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
1906Instruction</a> </div>
1907
1908<div class="doc_text">
1909
1910<h5>Syntax:</h5>
1911<pre>
1912 unreachable
1913</pre>
1914
1915<h5>Overview:</h5>
1916
1917<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
1918instruction is used to inform the optimizer that a particular portion of the
1919code is not reachable. This can be used to indicate that the code after a
1920no-return function cannot be reached, and other facts.</p>
1921
1922<h5>Semantics:</h5>
1923
1924<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
1925</div>
1926
1927
1928
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1929<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1930<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1931<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1932<p>Binary operators are used to do most of the computation in a
1933program. They require two operands, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]1934produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1935multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1936The result value of a binary operator is not
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1937necessarily the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1938<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1939</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1940<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1941<div class="doc_subsubsection"> <a name="i_add">'<tt>add</tt>'
1942Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1943<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1944<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1945<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]1946</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1947<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1948<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1949<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1950<p>The two arguments to the '<tt>add</tt>' instruction must be either <a
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1951 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a> values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1952 This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1953Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1954<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1955<p>The value produced is the integer or floating point sum of the two
1956operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1957<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1958<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]1959</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1960</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1961<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1962<div class="doc_subsubsection"> <a name="i_sub">'<tt>sub</tt>'
1963Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1964<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1965<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1966<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]1967</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1968<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1969<p>The '<tt>sub</tt>' instruction returns the difference of its two
1970operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1971<p>Note that the '<tt>sub</tt>' instruction is used to represent the '<tt>neg</tt>'
1972instruction present in most other intermediate representations.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1973<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1974<p>The two arguments to the '<tt>sub</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1975 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1976values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]1977This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]1978Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1979<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1980<p>The value produced is the integer or floating point difference of
1981the two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1982<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]1983<pre>
1984 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1985 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1986</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1987</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1988<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1989<div class="doc_subsubsection"> <a name="i_mul">'<tt>mul</tt>'
1990Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1991<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1992<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1993<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]1994</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1996<p>The '<tt>mul</tt>' instruction returns the product of its two
1997operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1998<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1999<p>The two arguments to the '<tt>mul</tt>' instruction must be either <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2000 href="#t_integer">integer</a> or <a href="#t_floating">floating point</a>
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2001values.
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2002This instruction can also take <a href="#t_vector">vector</a> versions of the values.
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2003Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2004<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2005<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2006two operands.</p>
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]2007<p>Because the operands are the same width, the result of an integer
2008multiplication is the same whether the operands should be deemed unsigned or
2009signed.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2010<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2011<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]2012</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2013</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2014<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2015<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2016</a></div>
2017<div class="doc_text">
2018<h5>Syntax:</h5>
2019<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2020</pre>
2021<h5>Overview:</h5>
2022<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2023operands.</p>
2024<h5>Arguments:</h5>
2025<p>The two arguments to the '<tt>udiv</tt>' instruction must be
2026<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2027types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2028of the values in which case the elements must be integers.</p>
2029<h5>Semantics:</h5>
2030<p>The value produced is the unsigned integer quotient of the two operands. This
2031instruction always performs an unsigned division operation, regardless of
2032whether the arguments are unsigned or not.</p>
2033<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2034<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]2035</pre>
2036</div>
2037<!-- _______________________________________________________________________ -->
2038<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2039</a> </div>
2040<div class="doc_text">
2041<h5>Syntax:</h5>
2042<pre> &lt;result&gt; = sdiv &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2043</pre>
2044<h5>Overview:</h5>
2045<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2046operands.</p>
2047<h5>Arguments:</h5>
2048<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2049<a href="#t_integer">integer</a> values. Both arguments must have identical
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2050types. This instruction can also take <a href="#t_vector">vector</a> versions
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2051of the values in which case the elements must be integers.</p>
2052<h5>Semantics:</h5>
2053<p>The value produced is the signed integer quotient of the two operands. This
2054instruction always performs a signed division operation, regardless of whether
2055the arguments are signed or not.</p>
2056<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2057<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]2058</pre>
2059</div>
2060<!-- _______________________________________________________________________ -->
2061<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2062Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2063<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2064<h5>Syntax:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2065<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]2066</pre>
2067<h5>Overview:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2068<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2069operands.</p>
2070<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2071<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2072<a href="#t_floating">floating point</a> values. Both arguments must have
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2073identical types. This instruction can also take <a href="#t_vector">vector</a>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2074versions of floating point values.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2075<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2076<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2077<h5>Example:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]2078<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]2079</pre>
2080</div>
2081<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2082<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2083</div>
2084<div class="doc_text">
2085<h5>Syntax:</h5>
2086<pre> &lt;result&gt; = urem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2087</pre>
2088<h5>Overview:</h5>
2089<p>The '<tt>urem</tt>' instruction returns the remainder from the
2090unsigned division of its two arguments.</p>
2091<h5>Arguments:</h5>
2092<p>The two arguments to the '<tt>urem</tt>' instruction must be
2093<a href="#t_integer">integer</a> values. Both arguments must have identical
2094types.</p>
2095<h5>Semantics:</h5>
2096<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
2097This instruction always performs an unsigned division to get the remainder,
2098regardless of whether the arguments are unsigned or not.</p>
2099<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2100<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]2101</pre>
2102
2103</div>
2104<!-- _______________________________________________________________________ -->
2105<div class="doc_subsubsection"> <a name="i_srem">'<tt>srem</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2106Instruction</a> </div>
2107<div class="doc_text">
2108<h5>Syntax:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2109<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]2110</pre>
2111<h5>Overview:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2112<p>The '<tt>srem</tt>' instruction returns the remainder from the
2113signed division of its two operands.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2114<h5>Arguments:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2115<p>The two arguments to the '<tt>srem</tt>' instruction must be
2116<a href="#t_integer">integer</a> values. Both arguments must have identical
2117types.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2118<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]2119<p>This instruction returns the <i>remainder</i> of a division (where the result
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2120has the same sign as the dividend, <tt>var1</tt>), not the <i>modulo</i>
2121operator (where the result has the same sign as the divisor, <tt>var2</tt>) of
2122a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2123 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2124Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +0000[diff] [blame]2125please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +0000[diff] [blame]2126Wikipedia: modulo operation</a>.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2127<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2128<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]2129</pre>
2130
2131</div>
2132<!-- _______________________________________________________________________ -->
2133<div class="doc_subsubsection"> <a name="i_frem">'<tt>frem</tt>'
2134Instruction</a> </div>
2135<div class="doc_text">
2136<h5>Syntax:</h5>
2137<pre> &lt;result&gt; = frem &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2138</pre>
2139<h5>Overview:</h5>
2140<p>The '<tt>frem</tt>' instruction returns the remainder from the
2141division of its two operands.</p>
2142<h5>Arguments:</h5>
2143<p>The two arguments to the '<tt>frem</tt>' instruction must be
2144<a href="#t_floating">floating point</a> values. Both arguments must have
2145identical types.</p>
2146<h5>Semantics:</h5>
2147<p>This instruction returns the <i>remainder</i> of a division.</p>
2148<h5>Example:</h5>
2149<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]2150</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2151</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]2152
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2153<!-- ======================================================================= -->
2154<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2155Operations</a> </div>
2156<div class="doc_text">
2157<p>Bitwise binary operators are used to do various forms of
2158bit-twiddling in a program. They are generally very efficient
2159instructions and can commonly be strength reduced from other
2160instructions. They require two operands, execute an operation on them,
2161and produce a single value. The resulting value of the bitwise binary
2162operators is always the same type as its first operand.</p>
2163</div>
2164
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2165<!-- _______________________________________________________________________ -->
2166<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2167Instruction</a> </div>
2168<div class="doc_text">
2169<h5>Syntax:</h5>
2170<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2171</pre>
2172<h5>Overview:</h5>
2173<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2174the left a specified number of bits.</p>
2175<h5>Arguments:</h5>
2176<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
2177 href="#t_integer">integer</a> type.</p>
2178<h5>Semantics:</h5>
2179<p>The value produced is <tt>var1</tt> * 2<sup><tt>var2</tt></sup>.</p>
2180<h5>Example:</h5><pre>
2181 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2182 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2183 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
2184</pre>
2185</div>
2186<!-- _______________________________________________________________________ -->
2187<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2188Instruction</a> </div>
2189<div class="doc_text">
2190<h5>Syntax:</h5>
2191<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2192</pre>
2193
2194<h5>Overview:</h5>
2195<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2196operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2197
2198<h5>Arguments:</h5>
2199<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
2200<a href="#t_integer">integer</a> type.</p>
2201
2202<h5>Semantics:</h5>
2203<p>This instruction always performs a logical shift right operation. The most
2204significant bits of the result will be filled with zero bits after the
2205shift.</p>
2206
2207<h5>Example:</h5>
2208<pre>
2209 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2210 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2211 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2212 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
2213</pre>
2214</div>
2215
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]2216<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2217<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2218Instruction</a> </div>
2219<div class="doc_text">
2220
2221<h5>Syntax:</h5>
2222<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {ty}:result</i>
2223</pre>
2224
2225<h5>Overview:</h5>
2226<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2227operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]2228
2229<h5>Arguments:</h5>
2230<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
2231<a href="#t_integer">integer</a> type.</p>
2232
2233<h5>Semantics:</h5>
2234<p>This instruction always performs an arithmetic shift right operation,
2235The most significant bits of the result will be filled with the sign bit
2236of <tt>var1</tt>.</p>
2237
2238<h5>Example:</h5>
2239<pre>
2240 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2241 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2242 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2243 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
2244</pre>
2245</div>
2246
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2247<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2248<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2249Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2250<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2251<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2252<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]2253</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2254<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2255<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2256its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2257<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2258<p>The two arguments to the '<tt>and</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2259 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2260identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2261<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2262<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2263<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2264<div style="align: center">
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2265<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2266 <tbody>
2267 <tr>
2268 <td>In0</td>
2269 <td>In1</td>
2270 <td>Out</td>
2271 </tr>
2272 <tr>
2273 <td>0</td>
2274 <td>0</td>
2275 <td>0</td>
2276 </tr>
2277 <tr>
2278 <td>0</td>
2279 <td>1</td>
2280 <td>0</td>
2281 </tr>
2282 <tr>
2283 <td>1</td>
2284 <td>0</td>
2285 <td>0</td>
2286 </tr>
2287 <tr>
2288 <td>1</td>
2289 <td>1</td>
2290 <td>1</td>
2291 </tr>
2292 </tbody>
2293</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2294</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2295<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2296<pre> &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
2297 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2298 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2299</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2300</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2301<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2302<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2303<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2304<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2305<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]2306</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2307<h5>Overview:</h5>
2308<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2309or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2310<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2311<p>The two arguments to the '<tt>or</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2312 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2313identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2314<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2315<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2316<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2317<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2318<table border="1" cellspacing="0" cellpadding="4">
2319 <tbody>
2320 <tr>
2321 <td>In0</td>
2322 <td>In1</td>
2323 <td>Out</td>
2324 </tr>
2325 <tr>
2326 <td>0</td>
2327 <td>0</td>
2328 <td>0</td>
2329 </tr>
2330 <tr>
2331 <td>0</td>
2332 <td>1</td>
2333 <td>1</td>
2334 </tr>
2335 <tr>
2336 <td>1</td>
2337 <td>0</td>
2338 <td>1</td>
2339 </tr>
2340 <tr>
2341 <td>1</td>
2342 <td>1</td>
2343 <td>1</td>
2344 </tr>
2345 </tbody>
2346</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2347</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2348<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2349<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
2350 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
2351 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2352</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2353</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2354<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2355<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
2356Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2357<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2358<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2359<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]2360</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2361<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2362<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
2363or of its two operands. The <tt>xor</tt> is used to implement the
2364"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2365<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2366<p>The two arguments to the '<tt>xor</tt>' instruction must be <a
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2367 href="#t_integer">integer</a> values. Both arguments must have
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2368identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2369<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2370<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2371<p> </p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2372<div style="align: center">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2373<table border="1" cellspacing="0" cellpadding="4">
2374 <tbody>
2375 <tr>
2376 <td>In0</td>
2377 <td>In1</td>
2378 <td>Out</td>
2379 </tr>
2380 <tr>
2381 <td>0</td>
2382 <td>0</td>
2383 <td>0</td>
2384 </tr>
2385 <tr>
2386 <td>0</td>
2387 <td>1</td>
2388 <td>1</td>
2389 </tr>
2390 <tr>
2391 <td>1</td>
2392 <td>0</td>
2393 <td>1</td>
2394 </tr>
2395 <tr>
2396 <td>1</td>
2397 <td>1</td>
2398 <td>0</td>
2399 </tr>
2400 </tbody>
2401</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2402</div>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2403<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2404<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2405<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
2406 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
2407 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
2408 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2409</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2410</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2411
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2412<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2413<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2414 <a name="vectorops">Vector Operations</a>
2415</div>
2416
2417<div class="doc_text">
2418
2419<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2420target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2421vector-specific operations needed to process vectors effectively. While LLVM
2422does directly support these vector operations, many sophisticated algorithms
2423will want to use target-specific intrinsics to take full advantage of a specific
2424target.</p>
2425
2426</div>
2427
2428<!-- _______________________________________________________________________ -->
2429<div class="doc_subsubsection">
2430 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
2431</div>
2432
2433<div class="doc_text">
2434
2435<h5>Syntax:</h5>
2436
2437<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2438 &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]2439</pre>
2440
2441<h5>Overview:</h5>
2442
2443<p>
2444The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2445element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2446</p>
2447
2448
2449<h5>Arguments:</h5>
2450
2451<p>
2452The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2453value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2454an index indicating the position from which to extract the element.
2455The index may be a variable.</p>
2456
2457<h5>Semantics:</h5>
2458
2459<p>
2460The result is a scalar of the same type as the element type of
2461<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
2462<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
2463results are undefined.
2464</p>
2465
2466<h5>Example:</h5>
2467
2468<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2469 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2470</pre>
2471</div>
2472
2473
2474<!-- _______________________________________________________________________ -->
2475<div class="doc_subsubsection">
2476 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
2477</div>
2478
2479<div class="doc_text">
2480
2481<h5>Syntax:</h5>
2482
2483<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2484 &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]2485</pre>
2486
2487<h5>Overview:</h5>
2488
2489<p>
2490The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2491element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2492</p>
2493
2494
2495<h5>Arguments:</h5>
2496
2497<p>
2498The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2499value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2500scalar value whose type must equal the element type of the first
2501operand. The third operand is an index indicating the position at
2502which to insert the value. The index may be a variable.</p>
2503
2504<h5>Semantics:</h5>
2505
2506<p>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2507The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2508element values are those of <tt>val</tt> except at position
2509<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
2510exceeds the length of <tt>val</tt>, the results are undefined.
2511</p>
2512
2513<h5>Example:</h5>
2514
2515<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2516 %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]2517</pre>
2518</div>
2519
2520<!-- _______________________________________________________________________ -->
2521<div class="doc_subsubsection">
2522 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
2523</div>
2524
2525<div class="doc_text">
2526
2527<h5>Syntax:</h5>
2528
2529<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2530 &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]2531</pre>
2532
2533<h5>Overview:</h5>
2534
2535<p>
2536The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
2537from two input vectors, returning a vector of the same type.
2538</p>
2539
2540<h5>Arguments:</h5>
2541
2542<p>
2543The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
2544with types that match each other and types that match the result of the
2545instruction. The third argument is a shuffle mask, which has the same number
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2546of elements as the other vector type, but whose element type is always 'i32'.
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2547</p>
2548
2549<p>
2550The shuffle mask operand is required to be a constant vector with either
2551constant integer or undef values.
2552</p>
2553
2554<h5>Semantics:</h5>
2555
2556<p>
2557The elements of the two input vectors are numbered from left to right across
2558both of the vectors. The shuffle mask operand specifies, for each element of
2559the result vector, which element of the two input registers the result element
2560gets. The element selector may be undef (meaning "don't care") and the second
2561operand may be undef if performing a shuffle from only one vector.
2562</p>
2563
2564<h5>Example:</h5>
2565
2566<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2567 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2568 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2569 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
2570 &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]2571</pre>
2572</div>
2573
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]2574
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]2575<!-- ======================================================================= -->
2576<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2577 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2578</div>
2579
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2580<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2581
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2582<p>A key design point of an SSA-based representation is how it
2583represents memory. In LLVM, no memory locations are in SSA form, which
2584makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2585allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2586
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2587</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2588
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2589<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2590<div class="doc_subsubsection">
2591 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
2592</div>
2593
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2594<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2595
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2596<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2597
2598<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2599 &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]2600</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2601
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2602<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2603
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2604<p>The '<tt>malloc</tt>' instruction allocates memory from the system
2605heap and returns a pointer to it.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2606
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2607<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2608
2609<p>The '<tt>malloc</tt>' instruction allocates
2610<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +0000[diff] [blame]2611bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2612appropriate type to the program. If "NumElements" is specified, it is the
2613number of elements allocated. If an alignment is specified, the value result
2614of the allocation is guaranteed to be aligned to at least that boundary. If
2615not specified, or if zero, the target can choose to align the allocation on any
2616convenient boundary.</p>
2617
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2618<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2619
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2620<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2621
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2622<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
2623a pointer is returned.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2624
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2625<h5>Example:</h5>
2626
2627<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2628 %array = malloc [4 x i8 ] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2629
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]2630 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
2631 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
2632 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
2633 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
2634 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2635</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2636</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2637
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2638<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2639<div class="doc_subsubsection">
2640 <a name="i_free">'<tt>free</tt>' Instruction</a>
2641</div>
2642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2643<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2644
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2645<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2646
2647<pre>
2648 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2649</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2650
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2651<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2652
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2653<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2654memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2655
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2656<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2657
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2658<p>'<tt>value</tt>' shall be a pointer value that points to a value
2659that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
2660instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2661
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2662<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2663
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2664<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2665after this instruction executes.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2666
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2667<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2668
2669<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2670 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
2671 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2672</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2673</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2674
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2675<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2676<div class="doc_subsubsection">
2677 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
2678</div>
2679
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2680<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2681
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2682<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2683
2684<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2685 &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]2686</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2687
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2688<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2689
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2690<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
2691currently executing function, to be automatically released when this function
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2692returns to its caller.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2693
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2694<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2695
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2696<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2697bytes of memory on the runtime stack, returning a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2698appropriate type to the program. If "NumElements" is specified, it is the
2699number of elements allocated. If an alignment is specified, the value result
2700of the allocation is guaranteed to be aligned to at least that boundary. If
2701not specified, or if zero, the target can choose to align the allocation on any
2702convenient boundary.</p>
2703
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2704<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2705
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2706<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2707
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2708<p>Memory is allocated; a pointer is returned. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2709memory is automatically released when the function returns. The '<tt>alloca</tt>'
2710instruction is commonly used to represent automatic variables that must
2711have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +0000[diff] [blame]2712 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]2713instructions), the memory is reclaimed.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2714
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2715<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2716
2717<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2718 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2719 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
2720 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2721 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2722</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2723</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]2724
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2725<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2726<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
2727Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2728<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2729<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2730<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2731<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2732<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2733<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2734<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2735address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +0000[diff] [blame]2736 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2737marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2738the number or order of execution of this <tt>load</tt> with other
2739volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
2740instructions. </p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2741<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2742<p>The location of memory pointed to is loaded.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2743<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2744<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2745 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2746 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2747 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2748</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2749</div>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2750<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2751<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
2752Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +0000[diff] [blame]2753<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2754<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +0000[diff] [blame]2755<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
2756 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2757</pre>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2758<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2759<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2760<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2761<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2762to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2763operand must be a pointer to the type of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2764operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2765optimizer is not allowed to modify the number or order of execution of
2766this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
2767 href="#i_store">store</a></tt> instructions.</p>
2768<h5>Semantics:</h5>
2769<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
2770at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.</p>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2771<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2772<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2773 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2774 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
2775 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2776</pre>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2777</div>
2778
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]2779<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2780<div class="doc_subsubsection">
2781 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
2782</div>
2783
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2784<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2785<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2786<pre>
2787 &lt;result&gt; = getelementptr &lt;ty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
2788</pre>
2789
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2790<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2791
2792<p>
2793The '<tt>getelementptr</tt>' instruction is used to get the address of a
2794subelement of an aggregate data structure.</p>
2795
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2796<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2797
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2798<p>This instruction takes a list of integer operands that indicate what
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2799elements of the aggregate object to index to. The actual types of the arguments
2800provided depend on the type of the first pointer argument. The
2801'<tt>getelementptr</tt>' instruction is used to index down through the type
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]2802levels 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]2803structure, only <tt>i32</tt> integer constants are allowed. When indexing
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2804into an array or pointer, only integers of 32 or 64 bits are allowed, and will
2805be sign extended to 64-bit values.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2806
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2807<p>For example, let's consider a C code fragment and how it gets
2808compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2809
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2810<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2811<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2812struct RT {
2813 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2814 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2815 char C;
2816};
2817struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2818 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2819 double Y;
2820 struct RT Z;
2821};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2822
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]2823int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2824 return &amp;s[1].Z.B[5][13];
2825}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2826</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2827</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2828
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2829<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2830
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2831<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2832<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2833%RT = type { i8 , [10 x [20 x i32]], i8 }
2834%ST = type { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2835
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2836define i32* %foo(%ST* %s) {
2837entry:
2838 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
2839 ret i32* %reg
2840}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2841</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2842</div>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2843
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2844<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2845
2846<p>The index types specified for the '<tt>getelementptr</tt>' instruction depend
John Criswell4a3327e2005-05-13 22:25:59 +0000[diff] [blame]2847on the pointer type that is being indexed into. <a href="#t_pointer">Pointer</a>
Reid Spencercee005c2006-12-04 21:29:24 +0000[diff] [blame]2848and <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]2849<a href="#t_integer">integer</a> type but the value will always be sign extended
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2850to 64-bits. <a href="#t_struct">Structure</a> types require <tt>i32</tt>
Reid Spencerc0312692006-12-03 16:53:48 +0000[diff] [blame]2851<b>constants</b>.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2852
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2853<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]2854type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2855}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2856the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
2857i8 }</tt>' type, another structure. The third index indexes into the second
2858element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2859array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2860'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
2861to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2862
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]2863<p>Note that it is perfectly legal to index partially through a
2864structure, returning a pointer to an inner element. Because of this,
2865the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2866
2867<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2868 define i32* %foo(%ST* %s) {
2869 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2870 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
2871 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2872 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
2873 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
2874 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2875 }
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2876</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2877
2878<p>Note that it is undefined to access an array out of bounds: array and
2879pointer indexes must always be within the defined bounds of the array type.
2880The one exception for this rules is zero length arrays. These arrays are
2881defined to be accessible as variable length arrays, which requires access
2882beyond the zero'th element.</p>
2883
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]2884<p>The getelementptr instruction is often confusing. For some more insight
2885into how it works, see <a href="GetElementPtr.html">the getelementptr
2886FAQ</a>.</p>
2887
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2888<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]2889
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2890<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2891 <i>; yields [12 x i8]*:aptr</i>
2892 %aptr = getelementptr {i32, [12 x i8]}* %sptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2893</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]2894</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]2895
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2896<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2897<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2898</div>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2899<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]2900<p>The instructions in this category are the conversion instructions (casting)
2901which all take a single operand and a type. They perform various bit conversions
2902on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2903</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2904
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]2905<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]2906<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2907 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
2908</div>
2909<div class="doc_text">
2910
2911<h5>Syntax:</h5>
2912<pre>
2913 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2914</pre>
2915
2916<h5>Overview:</h5>
2917<p>
2918The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
2919</p>
2920
2921<h5>Arguments:</h5>
2922<p>
2923The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
2924be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2925and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2926type. The bit size of <tt>value</tt> must be larger than the bit size of
2927<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2928
2929<h5>Semantics:</h5>
2930<p>
2931The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2932and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
2933larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
2934It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2935
2936<h5>Example:</h5>
2937<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2938 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2939 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
2940 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2941</pre>
2942</div>
2943
2944<!-- _______________________________________________________________________ -->
2945<div class="doc_subsubsection">
2946 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
2947</div>
2948<div class="doc_text">
2949
2950<h5>Syntax:</h5>
2951<pre>
2952 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2953</pre>
2954
2955<h5>Overview:</h5>
2956<p>The '<tt>zext</tt>' instruction zero extends its operand to type
2957<tt>ty2</tt>.</p>
2958
2959
2960<h5>Arguments:</h5>
2961<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2962<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2963also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2964<tt>value</tt> must be smaller than the bit size of the destination type,
2965<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2966
2967<h5>Semantics:</h5>
2968<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]2969bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2970
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]2971<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2972
2973<h5>Example:</h5>
2974<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2975 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]2976 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2977</pre>
2978</div>
2979
2980<!-- _______________________________________________________________________ -->
2981<div class="doc_subsubsection">
2982 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
2983</div>
2984<div class="doc_text">
2985
2986<h5>Syntax:</h5>
2987<pre>
2988 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
2989</pre>
2990
2991<h5>Overview:</h5>
2992<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
2993
2994<h5>Arguments:</h5>
2995<p>
2996The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]2997<a href="#t_integer">integer</a> type, and a type to cast it to, which must
2998also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]2999<tt>value</tt> must be smaller than the bit size of the destination type,
3000<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3001
3002<h5>Semantics:</h5>
3003<p>
3004The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3005bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerc87f3df2007-05-24 19:13:27 +0000[diff] [blame]3006the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3007
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3008<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3009
3010<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3011<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3012 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3013 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3014</pre>
3015</div>
3016
3017<!-- _______________________________________________________________________ -->
3018<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3019 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3020</div>
3021
3022<div class="doc_text">
3023
3024<h5>Syntax:</h5>
3025
3026<pre>
3027 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3028</pre>
3029
3030<h5>Overview:</h5>
3031<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3032<tt>ty2</tt>.</p>
3033
3034
3035<h5>Arguments:</h5>
3036<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3037 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3038cast it to. The size of <tt>value</tt> must be larger than the size of
3039<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3040<i>no-op cast</i>.</p>
3041
3042<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3043<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3044<a href="#t_floating">floating point</a> type to a smaller
3045<a href="#t_floating">floating point</a> type. If the value cannot fit within
3046the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]3047
3048<h5>Example:</h5>
3049<pre>
3050 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3051 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3052</pre>
3053</div>
3054
3055<!-- _______________________________________________________________________ -->
3056<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3057 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3058</div>
3059<div class="doc_text">
3060
3061<h5>Syntax:</h5>
3062<pre>
3063 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3064</pre>
3065
3066<h5>Overview:</h5>
3067<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3068floating point value.</p>
3069
3070<h5>Arguments:</h5>
3071<p>The '<tt>fpext</tt>' instruction takes a
3072<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3073and a <a href="#t_floating">floating point</a> type to cast it to. The source
3074type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3075
3076<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3077<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3078<a href="#t_floating">floating point</a> type to a larger
3079<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3080used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3081<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]3082
3083<h5>Example:</h5>
3084<pre>
3085 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3086 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3087</pre>
3088</div>
3089
3090<!-- _______________________________________________________________________ -->
3091<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]3092 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3093</div>
3094<div class="doc_text">
3095
3096<h5>Syntax:</h5>
3097<pre>
3098 &lt;result&gt; = fp2uint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3099</pre>
3100
3101<h5>Overview:</h5>
3102<p>The '<tt>fp2uint</tt>' converts a floating point <tt>value</tt> to its
3103unsigned integer equivalent of type <tt>ty2</tt>.
3104</p>
3105
3106<h5>Arguments:</h5>
3107<p>The '<tt>fp2uint</tt>' instruction takes a value to cast, which must be a
3108<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3109must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3110
3111<h5>Semantics:</h5>
3112<p> The '<tt>fp2uint</tt>' instruction converts its
3113<a href="#t_floating">floating point</a> operand into the nearest (rounding
3114towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3115the results are undefined.</p>
3116
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3117<p>When converting to i1, the conversion is done as a comparison against
3118zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3119If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3120
3121<h5>Example:</h5>
3122<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3123 %X = fp2uint double 123.0 to i32 <i>; yields i32:123</i>
3124 %Y = fp2uint float 1.0E+300 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3125 %X = fp2uint float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3126</pre>
3127</div>
3128
3129<!-- _______________________________________________________________________ -->
3130<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3131 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3132</div>
3133<div class="doc_text">
3134
3135<h5>Syntax:</h5>
3136<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3137 &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]3138</pre>
3139
3140<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3141<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3142<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]3143</p>
3144
3145
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3146<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3147<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]3148<a href="#t_floating">floating point</a> value, and a type to cast it to, which
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3149must also be an <a href="#t_integer">integer</a> type.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3150
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3151<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3152<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3153<a href="#t_floating">floating point</a> operand into the nearest (rounding
3154towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3155the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3156
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3157<p>When converting to i1, the conversion is done as a comparison against
3158zero. If the <tt>value</tt> was zero, the i1 result will be <tt>false</tt>.
3159If the <tt>value</tt> was non-zero, the i1 result will be <tt>true</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3160
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3161<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3162<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3163 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
3164 %Y = fptosi float 1.0E-247 to i1 <i>; yields i1:true</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3165 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3166</pre>
3167</div>
3168
3169<!-- _______________________________________________________________________ -->
3170<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3171 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3172</div>
3173<div class="doc_text">
3174
3175<h5>Syntax:</h5>
3176<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3177 &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]3178</pre>
3179
3180<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3181<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3182integer and converts that value to the <tt>ty2</tt> type.</p>
3183
3184
3185<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3186<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3187<a href="#t_integer">integer</a> value, and a type to cast it to, which must
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3188be a <a href="#t_floating">floating point</a> type.</p>
3189
3190<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3191<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3192integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3193the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3194
3195
3196<h5>Example:</h5>
3197<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3198 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3199 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3200</pre>
3201</div>
3202
3203<!-- _______________________________________________________________________ -->
3204<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3205 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3206</div>
3207<div class="doc_text">
3208
3209<h5>Syntax:</h5>
3210<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3211 &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]3212</pre>
3213
3214<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3215<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3216integer and converts that value to the <tt>ty2</tt> type.</p>
3217
3218<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3219<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be an
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3220<a href="#t_integer">integer</a> value, and a type to cast it to, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3221a <a href="#t_floating">floating point</a> type.</p>
3222
3223<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]3224<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3225integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +0000[diff] [blame]3226the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3227
3228<h5>Example:</h5>
3229<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3230 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3231 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3232</pre>
3233</div>
3234
3235<!-- _______________________________________________________________________ -->
3236<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3237 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
3238</div>
3239<div class="doc_text">
3240
3241<h5>Syntax:</h5>
3242<pre>
3243 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3244</pre>
3245
3246<h5>Overview:</h5>
3247<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
3248the integer type <tt>ty2</tt>.</p>
3249
3250<h5>Arguments:</h5>
3251<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3252must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3253<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.
3254
3255<h5>Semantics:</h5>
3256<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
3257<tt>ty2</tt> by interpreting the pointer value as an integer and either
3258truncating or zero extending that value to the size of the integer type. If
3259<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
3260<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3261are the same size, then nothing is done (<i>no-op cast</i>) other than a type
3262change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3263
3264<h5>Example:</h5>
3265<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3266 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
3267 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3268</pre>
3269</div>
3270
3271<!-- _______________________________________________________________________ -->
3272<div class="doc_subsubsection">
3273 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
3274</div>
3275<div class="doc_text">
3276
3277<h5>Syntax:</h5>
3278<pre>
3279 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3280</pre>
3281
3282<h5>Overview:</h5>
3283<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
3284a pointer type, <tt>ty2</tt>.</p>
3285
3286<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3287<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3288value to cast, and a type to cast it to, which must be a
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]3289<a href="#t_pointer">pointer</a> type.
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3290
3291<h5>Semantics:</h5>
3292<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
3293<tt>ty2</tt> by applying either a zero extension or a truncation depending on
3294the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
3295size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
3296the size of a pointer then a zero extension is done. If they are the same size,
3297nothing is done (<i>no-op cast</i>).</p>
3298
3299<h5>Example:</h5>
3300<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3301 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
3302 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
3303 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3304</pre>
3305</div>
3306
3307<!-- _______________________________________________________________________ -->
3308<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3309 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3310</div>
3311<div class="doc_text">
3312
3313<h5>Syntax:</h5>
3314<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3315 &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]3316</pre>
3317
3318<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3319<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3320<tt>ty2</tt> without changing any bits.</p>
3321
3322<h5>Arguments:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3323<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3324a first class value, and a type to cast it to, which must also be a <a
3325 href="#t_firstclass">first class</a> type. The bit sizes of <tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +0000[diff] [blame]3326and the destination type, <tt>ty2</tt>, must be identical. If the source
3327type is a pointer, the destination type must also be a pointer.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3328
3329<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]3330<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]3331<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
3332this conversion. The conversion is done as if the <tt>value</tt> had been
3333stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
3334converted to other pointer types with this instruction. To convert pointers to
3335other types, use the <a href="#i_inttoptr">inttoptr</a> or
3336<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]3337
3338<h5>Example:</h5>
3339<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3340 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3341 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
3342 %Z = bitcast <2xint> %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]3343</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3344</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3345
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3346<!-- ======================================================================= -->
3347<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
3348<div class="doc_text">
3349<p>The instructions in this category are the "miscellaneous"
3350instructions, which defy better classification.</p>
3351</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3352
3353<!-- _______________________________________________________________________ -->
3354<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
3355</div>
3356<div class="doc_text">
3357<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3358<pre> &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3359</pre>
3360<h5>Overview:</h5>
3361<p>The '<tt>icmp</tt>' instruction returns a boolean value based on comparison
3362of its two integer operands.</p>
3363<h5>Arguments:</h5>
3364<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3365the condition code indicating the kind of comparison to perform. It is not
3366a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3367<ol>
3368 <li><tt>eq</tt>: equal</li>
3369 <li><tt>ne</tt>: not equal </li>
3370 <li><tt>ugt</tt>: unsigned greater than</li>
3371 <li><tt>uge</tt>: unsigned greater or equal</li>
3372 <li><tt>ult</tt>: unsigned less than</li>
3373 <li><tt>ule</tt>: unsigned less or equal</li>
3374 <li><tt>sgt</tt>: signed greater than</li>
3375 <li><tt>sge</tt>: signed greater or equal</li>
3376 <li><tt>slt</tt>: signed less than</li>
3377 <li><tt>sle</tt>: signed less or equal</li>
3378</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]3379<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3380<a href="#t_pointer">pointer</a> typed. They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3381<h5>Semantics:</h5>
3382<p>The '<tt>icmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3383the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3384yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3385<ol>
3386 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
3387 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3388 </li>
3389 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
3390 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
3391 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
3392 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3393 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
3394 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3395 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
3396 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3397 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
3398 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
3399 <li><tt>sgt</tt>: interprets the operands as signed values and yields
3400 <tt>true</tt> if <tt>var1</tt> is greater than <tt>var2</tt>.</li>
3401 <li><tt>sge</tt>: interprets the operands as signed values and yields
3402 <tt>true</tt> if <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
3403 <li><tt>slt</tt>: interprets the operands as signed values and yields
3404 <tt>true</tt> if <tt>var1</tt> is less than <tt>var2</tt>.</li>
3405 <li><tt>sle</tt>: interprets the operands as signed values and yields
3406 <tt>true</tt> if <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3407</ol>
3408<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3409values are compared as if they were integers.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3410
3411<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3412<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
3413 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
3414 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
3415 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
3416 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
3417 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3418</pre>
3419</div>
3420
3421<!-- _______________________________________________________________________ -->
3422<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
3423</div>
3424<div class="doc_text">
3425<h5>Syntax:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3426<pre> &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;var1&gt;, &lt;var2&gt; <i>; yields {i1}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3427</pre>
3428<h5>Overview:</h5>
3429<p>The '<tt>fcmp</tt>' instruction returns a boolean value based on comparison
3430of its floating point operands.</p>
3431<h5>Arguments:</h5>
3432<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3433the condition code indicating the kind of comparison to perform. It is not
3434a value, just a keyword. The possible condition code are:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3435<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3436 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3437 <li><tt>oeq</tt>: ordered and equal</li>
3438 <li><tt>ogt</tt>: ordered and greater than </li>
3439 <li><tt>oge</tt>: ordered and greater than or equal</li>
3440 <li><tt>olt</tt>: ordered and less than </li>
3441 <li><tt>ole</tt>: ordered and less than or equal</li>
3442 <li><tt>one</tt>: ordered and not equal</li>
3443 <li><tt>ord</tt>: ordered (no nans)</li>
3444 <li><tt>ueq</tt>: unordered or equal</li>
3445 <li><tt>ugt</tt>: unordered or greater than </li>
3446 <li><tt>uge</tt>: unordered or greater than or equal</li>
3447 <li><tt>ult</tt>: unordered or less than </li>
3448 <li><tt>ule</tt>: unordered or less than or equal</li>
3449 <li><tt>une</tt>: unordered or not equal</li>
3450 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3451 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3452</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3453<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +0000[diff] [blame]3454<i>unordered</i> means that either operand may be a QNAN.</p>
Reid Spencer784ef792007-01-04 05:19:58 +0000[diff] [blame]3455<p>The <tt>val1</tt> and <tt>val2</tt> arguments must be
3456<a href="#t_floating">floating point</a> typed. They must have identical
3457types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3458<h5>Semantics:</h5>
3459<p>The '<tt>fcmp</tt>' compares <tt>var1</tt> and <tt>var2</tt> according to
3460the condition code given as <tt>cond</tt>. The comparison performed always
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3461yields a <a href="#t_primitive">i1</a> result, as follows:
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3462<ol>
3463 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3464 <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]3465 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3466 <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]3467 <tt>var1</tt> is greather than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3468 <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]3469 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3470 <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]3471 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3472 <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]3473 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3474 <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]3475 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3476 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
3477 <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]3478 <tt>var1</tt> is equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3479 <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]3480 <tt>var1</tt> is greater than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3481 <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]3482 <tt>var1</tt> is greater than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3483 <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]3484 <tt>var1</tt> is less than <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3485 <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]3486 <tt>var1</tt> is less than or equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3487 <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]3488 <tt>var1</tt> is not equal to <tt>var2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]3489 <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]3490 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
3491</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]3492
3493<h5>Example:</h5>
3494<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
3495 &lt;result&gt; = icmp one float 4.0, 5.0 <i>; yields: result=true</i>
3496 &lt;result&gt; = icmp olt float 4.0, 5.0 <i>; yields: result=true</i>
3497 &lt;result&gt; = icmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
3498</pre>
3499</div>
3500
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3501<!-- _______________________________________________________________________ -->
3502<div class="doc_subsubsection"> <a name="i_phi">'<tt>phi</tt>'
3503Instruction</a> </div>
3504<div class="doc_text">
3505<h5>Syntax:</h5>
3506<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
3507<h5>Overview:</h5>
3508<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
3509the SSA graph representing the function.</p>
3510<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3511<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3512field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
3513as arguments, with one pair for each predecessor basic block of the
3514current block. Only values of <a href="#t_firstclass">first class</a>
3515type may be used as the value arguments to the PHI node. Only labels
3516may be used as the label arguments.</p>
3517<p>There must be no non-phi instructions between the start of a basic
3518block and the PHI instructions: i.e. PHI instructions must be first in
3519a basic block.</p>
3520<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3521<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
3522specified by the pair corresponding to the predecessor basic block that executed
3523just prior to the current block.</p>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]3524<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3525<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]3526</div>
3527
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3528<!-- _______________________________________________________________________ -->
3529<div class="doc_subsubsection">
3530 <a name="i_select">'<tt>select</tt>' Instruction</a>
3531</div>
3532
3533<div class="doc_text">
3534
3535<h5>Syntax:</h5>
3536
3537<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3538 &lt;result&gt; = select i1 &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3539</pre>
3540
3541<h5>Overview:</h5>
3542
3543<p>
3544The '<tt>select</tt>' instruction is used to choose one value based on a
3545condition, without branching.
3546</p>
3547
3548
3549<h5>Arguments:</h5>
3550
3551<p>
3552The '<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.
3553</p>
3554
3555<h5>Semantics:</h5>
3556
3557<p>
3558If the boolean condition evaluates to true, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3559value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3560</p>
3561
3562<h5>Example:</h5>
3563
3564<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3565 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]3566</pre>
3567</div>
3568
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]3569
3570<!-- _______________________________________________________________________ -->
3571<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3572 <a name="i_call">'<tt>call</tt>' Instruction</a>
3573</div>
3574
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3575<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3576
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3577<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3578<pre>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3579 &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]3580</pre>
3581
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3582<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3583
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3584<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3585
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3586<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3587
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3588<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3589
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3590<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3591 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3592 <p>The optional "tail" marker indicates whether the callee function accesses
3593 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3594 function call is eligible for tail call optimization. Note that calls may
3595 be marked "tail" even if they do not occur before a <a
3596 href="#i_ret"><tt>ret</tt></a> instruction.
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3597 </li>
3598 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]3599 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3600 convention</a> the call should use. If none is specified, the call defaults
3601 to using C calling conventions.
3602 </li>
3603 <li>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3604 <p>'<tt>ty</tt>': shall be the signature of the pointer to function value
3605 being invoked. The argument types must match the types implied by this
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3606 signature. This type can be omitted if the function is not varargs and
3607 if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3608 </li>
3609 <li>
3610 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
3611 be invoked. In most cases, this is a direct function invocation, but
3612 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3613 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3614 </li>
3615 <li>
3616 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +0000[diff] [blame]3617 function signature argument types. All arguments must be of
3618 <a href="#t_firstclass">first class</a> type. If the function signature
3619 indicates the function accepts a variable number of arguments, the extra
3620 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3621 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3622</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3623
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3624<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3625
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3626<p>The '<tt>call</tt>' instruction is used to cause control flow to
3627transfer to a specified function, with its incoming arguments bound to
3628the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
3629instruction in the called function, control flow continues with the
3630instruction after the function call, and the return value of the
3631function is bound to the result argument. This is a simpler case of
3632the <a href="#i_invoke">invoke</a> instruction.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3633
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3634<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3635
3636<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3637 %retval = call i32 %test(i32 %argc)
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3638 call i32(i8 *, ...) *%printf(i8 * %msg, i32 12, i8 42);
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3639 %X = tail call i32 %foo()
3640 %Y = tail call <a href="#callingconv">fastcc</a> i32 %foo()
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]3641</pre>
3642
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3643</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3644
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3645<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3646<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3647 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3648</div>
3649
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3650<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3651
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3652<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3653
3654<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3655 &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]3656</pre>
3657
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3658<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3659
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3660<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3661the "variable argument" area of a function call. It is used to implement the
3662<tt>va_arg</tt> macro in C.</p>
3663
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3664<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3665
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3666<p>This instruction takes a <tt>va_list*</tt> value and the type of
3667the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3668increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3669actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3670
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3671<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3672
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3673<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
3674type from the specified <tt>va_list</tt> and causes the
3675<tt>va_list</tt> to point to the next argument. For more information,
3676see the variable argument handling <a href="#int_varargs">Intrinsic
3677Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3678
3679<p>It is legal for this instruction to be called in a function which does not
3680take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3681function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3682
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3683<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3684href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3685argument.</p>
3686
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]3687<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]3688
3689<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
3690
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3691</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3692
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3693<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3694<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
3695<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3696
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3697<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3698
3699<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3700well known names and semantics and are required to follow certain restrictions.
3701Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3702language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +0000[diff] [blame]3703adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3704
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]3705<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3706prefix is reserved in LLVM for intrinsic names; thus, function names may not
3707begin with this prefix. Intrinsic functions must always be external functions:
3708you cannot define the body of intrinsic functions. Intrinsic functions may
3709only be used in call or invoke instructions: it is illegal to take the address
3710of an intrinsic function. Additionally, because intrinsic functions are part
3711of the LLVM language, it is required if any are added that they be documented
3712here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3713
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3714<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3715a family of functions that perform the same operation but on different data
3716types. This is most frequent with the integer types. Since LLVM can represent
3717over 8 million different integer types, there is a way to declare an intrinsic
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3718that can be overloaded based on its arguments. Such an intrinsic will have the
3719names of its argument types encoded into its function name, each
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3720preceded by a period. For example, the <tt>llvm.ctpop</tt> function can take an
3721integer of any width. This leads to a family of functions such as
3722<tt>i32 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i32 @llvm.ctpop.i29(i29 %val)</tt>.
3723</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3724
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]3725
3726<p>To learn how to add an intrinsic function, please see the
3727<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3728</p>
3729
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3730</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3731
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3732<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3733<div class="doc_subsection">
3734 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
3735</div>
3736
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3737<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3738
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3739<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]3740 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3741intrinsic functions. These functions are related to the similarly
3742named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3743
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3744<p>All of these functions operate on arguments that use a
3745target-specific value type "<tt>va_list</tt>". The LLVM assembly
3746language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3747transformations should be prepared to handle these functions regardless of
3748the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3749
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]3750<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]3751instruction and the variable argument handling intrinsic functions are
3752used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3753
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3754<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3755<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3756define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3757 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3758 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3759 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3760 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3761
3762 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3763 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3764
3765 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3766 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3767 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3768 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3769 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3770
3771 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3772 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3773 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3774}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]3775
3776declare void @llvm.va_start(i8*)
3777declare void @llvm.va_copy(i8*, i8*)
3778declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3779</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3780</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3781
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]3782</div>
3783
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3784<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3785<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3786 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3787</div>
3788
3789
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3790<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3791<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3792<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3793<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3794<P>The '<tt>llvm.va_start</tt>' intrinsic initializes
3795<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
3796href="#i_va_arg">va_arg</a></tt>.</p>
3797
3798<h5>Arguments:</h5>
3799
3800<P>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
3801
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3802<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3803
3804<P>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
3805macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3806<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3807<tt>va_arg</tt> will produce the first variable argument passed to the function.
3808Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3809last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3810
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3811</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3812
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3813<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3814<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3815 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3816</div>
3817
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3818<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3819<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3820<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3821<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3822
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3823<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3824which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3825or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3826
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3827<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3828
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3829<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3830
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3831<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3832
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3833<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3834macro available in C. In a target-dependent way, it destroys the
3835<tt>va_list</tt> element to which the argument points. Calls to <a
3836href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
3837<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
3838<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]3839
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3840</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3841
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3842<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3843<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3844 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3845</div>
3846
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3847<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3848
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3849<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3850
3851<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3852 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3853</pre>
3854
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3855<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3856
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3857<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
3858from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3859
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3860<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3861
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]3862<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]3863The 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]3864
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3865
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]3866<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3867
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]3868<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
3869macro available in C. In a target-dependent way, it copies the source
3870<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
3871intrinsic is necessary because the <tt><a href="#int_va_start">
3872llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
3873example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3874
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3875</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]3876
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]3877<!-- ======================================================================= -->
3878<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3879 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
3880</div>
3881
3882<div class="doc_text">
3883
3884<p>
3885LLVM support for <a href="GarbageCollection.html">Accurate Garbage
3886Collection</a> requires the implementation and generation of these intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3887These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3888stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3889href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3890Front-ends for type-safe garbage collected languages should generate these
3891intrinsics to make use of the LLVM garbage collectors. For more details, see <a
3892href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
3893</p>
3894</div>
3895
3896<!-- _______________________________________________________________________ -->
3897<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3898 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3899</div>
3900
3901<div class="doc_text">
3902
3903<h5>Syntax:</h5>
3904
3905<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3906 declare void @llvm.gcroot(&lt;ty&gt;** %ptrloc, &lt;ty2&gt;* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3907</pre>
3908
3909<h5>Overview:</h5>
3910
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]3911<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]3912the code generator, and allows some metadata to be associated with it.</p>
3913
3914<h5>Arguments:</h5>
3915
3916<p>The first argument specifies the address of a stack object that contains the
3917root pointer. The second pointer (which must be either a constant or a global
3918value address) contains the meta-data to be associated with the root.</p>
3919
3920<h5>Semantics:</h5>
3921
3922<p>At runtime, a call to this intrinsics stores a null pointer into the "ptrloc"
3923location. At compile-time, the code generator generates information to allow
3924the runtime to find the pointer at GC safe points.
3925</p>
3926
3927</div>
3928
3929
3930<!-- _______________________________________________________________________ -->
3931<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3932 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3933</div>
3934
3935<div class="doc_text">
3936
3937<h5>Syntax:</h5>
3938
3939<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3940 declare i8 * @llvm.gcread(i8 * %ObjPtr, i8 ** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3941</pre>
3942
3943<h5>Overview:</h5>
3944
3945<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
3946locations, allowing garbage collector implementations that require read
3947barriers.</p>
3948
3949<h5>Arguments:</h5>
3950
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3951<p>The second argument is the address to read from, which should be an address
3952allocated from the garbage collector. The first object is a pointer to the
3953start of the referenced object, if needed by the language runtime (otherwise
3954null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3955
3956<h5>Semantics:</h5>
3957
3958<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
3959instruction, but may be replaced with substantially more complex code by the
3960garbage collector runtime, as needed.</p>
3961
3962</div>
3963
3964
3965<!-- _______________________________________________________________________ -->
3966<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]3967 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3968</div>
3969
3970<div class="doc_text">
3971
3972<h5>Syntax:</h5>
3973
3974<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]3975 declare void @llvm.gcwrite(i8 * %P1, i8 * %Obj, i8 ** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3976</pre>
3977
3978<h5>Overview:</h5>
3979
3980<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
3981locations, allowing garbage collector implementations that require write
3982barriers (such as generational or reference counting collectors).</p>
3983
3984<h5>Arguments:</h5>
3985
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]3986<p>The first argument is the reference to store, the second is the start of the
3987object to store it to, and the third is the address of the field of Obj to
3988store to. If the runtime does not require a pointer to the object, Obj may be
3989null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]3990
3991<h5>Semantics:</h5>
3992
3993<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
3994instruction, but may be replaced with substantially more complex code by the
3995garbage collector runtime, as needed.</p>
3996
3997</div>
3998
3999
4000
4001<!-- ======================================================================= -->
4002<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4003 <a name="int_codegen">Code Generator Intrinsics</a>
4004</div>
4005
4006<div class="doc_text">
4007<p>
4008These intrinsics are provided by LLVM to expose special features that may only
4009be implemented with code generator support.
4010</p>
4011
4012</div>
4013
4014<!-- _______________________________________________________________________ -->
4015<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4016 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4017</div>
4018
4019<div class="doc_text">
4020
4021<h5>Syntax:</h5>
4022<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4023 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4024</pre>
4025
4026<h5>Overview:</h5>
4027
4028<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4029The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
4030target-specific value indicating the return address of the current function
4031or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4032</p>
4033
4034<h5>Arguments:</h5>
4035
4036<p>
4037The argument to this intrinsic indicates which function to return the address
4038for. Zero indicates the calling function, one indicates its caller, etc. The
4039argument is <b>required</b> to be a constant integer value.
4040</p>
4041
4042<h5>Semantics:</h5>
4043
4044<p>
4045The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
4046the return address of the specified call frame, or zero if it cannot be
4047identified. The value returned by this intrinsic is likely to be incorrect or 0
4048for arguments other than zero, so it should only be used for debugging purposes.
4049</p>
4050
4051<p>
4052Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4053aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4054source-language caller.
4055</p>
4056</div>
4057
4058
4059<!-- _______________________________________________________________________ -->
4060<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4061 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4062</div>
4063
4064<div class="doc_text">
4065
4066<h5>Syntax:</h5>
4067<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4068 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4069</pre>
4070
4071<h5>Overview:</h5>
4072
4073<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +0000[diff] [blame]4074The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
4075target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4076</p>
4077
4078<h5>Arguments:</h5>
4079
4080<p>
4081The argument to this intrinsic indicates which function to return the frame
4082pointer for. Zero indicates the calling function, one indicates its caller,
4083etc. The argument is <b>required</b> to be a constant integer value.
4084</p>
4085
4086<h5>Semantics:</h5>
4087
4088<p>
4089The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
4090the frame address of the specified call frame, or zero if it cannot be
4091identified. The value returned by this intrinsic is likely to be incorrect or 0
4092for arguments other than zero, so it should only be used for debugging purposes.
4093</p>
4094
4095<p>
4096Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +0000[diff] [blame]4097aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4098source-language caller.
4099</p>
4100</div>
4101
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4102<!-- _______________________________________________________________________ -->
4103<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4104 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4105</div>
4106
4107<div class="doc_text">
4108
4109<h5>Syntax:</h5>
4110<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4111 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4112</pre>
4113
4114<h5>Overview:</h5>
4115
4116<p>
4117The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4118the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4119<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
4120features like scoped automatic variable sized arrays in C99.
4121</p>
4122
4123<h5>Semantics:</h5>
4124
4125<p>
4126This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4127href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4128<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
4129<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
4130state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
4131practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
4132that were allocated after the <tt>llvm.stacksave</tt> was executed.
4133</p>
4134
4135</div>
4136
4137<!-- _______________________________________________________________________ -->
4138<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4139 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4140</div>
4141
4142<div class="doc_text">
4143
4144<h5>Syntax:</h5>
4145<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4146 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4147</pre>
4148
4149<h5>Overview:</h5>
4150
4151<p>
4152The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
4153the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4154href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4155useful for implementing language features like scoped automatic variable sized
4156arrays in C99.
4157</p>
4158
4159<h5>Semantics:</h5>
4160
4161<p>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4162See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]4163</p>
4164
4165</div>
4166
4167
4168<!-- _______________________________________________________________________ -->
4169<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4170 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4171</div>
4172
4173<div class="doc_text">
4174
4175<h5>Syntax:</h5>
4176<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4177 declare void @llvm.prefetch(i8 * &lt;address&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4178 i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4179</pre>
4180
4181<h5>Overview:</h5>
4182
4183
4184<p>
4185The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4186a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
4187no
4188effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +0000[diff] [blame]4189characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4190</p>
4191
4192<h5>Arguments:</h5>
4193
4194<p>
4195<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
4196determining if the fetch should be for a read (0) or write (1), and
4197<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +0000[diff] [blame]4198locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]4199<tt>locality</tt> arguments must be constant integers.
4200</p>
4201
4202<h5>Semantics:</h5>
4203
4204<p>
4205This intrinsic does not modify the behavior of the program. In particular,
4206prefetches cannot trap and do not produce a value. On targets that support this
4207intrinsic, the prefetch can provide hints to the processor cache for better
4208performance.
4209</p>
4210
4211</div>
4212
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4213<!-- _______________________________________________________________________ -->
4214<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4215 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4216</div>
4217
4218<div class="doc_text">
4219
4220<h5>Syntax:</h5>
4221<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4222 declare void @llvm.pcmarker( i32 &lt;id&gt; )
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4223</pre>
4224
4225<h5>Overview:</h5>
4226
4227
4228<p>
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4229The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
4230(PC) in a region of
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4231code to simulators and other tools. The method is target specific, but it is
4232expected that the marker will use exported symbols to transmit the PC of the marker.
Jeff Cohendc6bfea2005-11-11 02:15:27 +0000[diff] [blame]4233The marker makes no guarantees that it will remain with any specific instruction
Chris Lattnere64d41d2005-11-15 06:07:55 +0000[diff] [blame]4234after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +0000[diff] [blame]4235optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]4236correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]4237</p>
4238
4239<h5>Arguments:</h5>
4240
4241<p>
4242<tt>id</tt> is a numerical id identifying the marker.
4243</p>
4244
4245<h5>Semantics:</h5>
4246
4247<p>
4248This intrinsic does not modify the behavior of the program. Backends that do not
4249support this intrinisic may ignore it.
4250</p>
4251
4252</div>
4253
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4254<!-- _______________________________________________________________________ -->
4255<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4256 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4257</div>
4258
4259<div class="doc_text">
4260
4261<h5>Syntax:</h5>
4262<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4263 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]4264</pre>
4265
4266<h5>Overview:</h5>
4267
4268
4269<p>
4270The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
4271counter register (or similar low latency, high accuracy clocks) on those targets
4272that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
4273As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
4274should only be used for small timings.
4275</p>
4276
4277<h5>Semantics:</h5>
4278
4279<p>
4280When directly supported, reading the cycle counter should not modify any memory.
4281Implementations are allowed to either return a application specific value or a
4282system wide value. On backends without support, this is lowered to a constant 0.
4283</p>
4284
4285</div>
4286
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4287<!-- ======================================================================= -->
4288<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4289 <a name="int_libc">Standard C Library Intrinsics</a>
4290</div>
4291
4292<div class="doc_text">
4293<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4294LLVM provides intrinsics for a few important standard C library functions.
4295These intrinsics allow source-language front-ends to pass information about the
4296alignment of the pointer arguments to the code generator, providing opportunity
4297for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4298</p>
4299
4300</div>
4301
4302<!-- _______________________________________________________________________ -->
4303<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4304 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4305</div>
4306
4307<div class="doc_text">
4308
4309<h5>Syntax:</h5>
4310<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4311 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4312 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4313 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4314 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4315</pre>
4316
4317<h5>Overview:</h5>
4318
4319<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4320The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4321location to the destination location.
4322</p>
4323
4324<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4325Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
4326intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4327</p>
4328
4329<h5>Arguments:</h5>
4330
4331<p>
4332The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4333the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4334specifying the number of bytes to copy, and the fourth argument is the alignment
4335of the source and destination locations.
4336</p>
4337
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4338<p>
4339If 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]4340the caller guarantees that both the source and destination pointers are aligned
4341to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4342</p>
4343
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4344<h5>Semantics:</h5>
4345
4346<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4347The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]4348location to the destination location, which are not allowed to overlap. It
4349copies "len" bytes of memory over. If the argument is known to be aligned to
4350some boundary, this can be specified as the fourth argument, otherwise it should
4351be set to 0 or 1.
4352</p>
4353</div>
4354
4355
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4356<!-- _______________________________________________________________________ -->
4357<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4358 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4359</div>
4360
4361<div class="doc_text">
4362
4363<h5>Syntax:</h5>
4364<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4365 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4366 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4367 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4368 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4369</pre>
4370
4371<h5>Overview:</h5>
4372
4373<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4374The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
4375location to the destination location. It is similar to the
4376'<tt>llvm.memcmp</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4377</p>
4378
4379<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4380Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
4381intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4382</p>
4383
4384<h5>Arguments:</h5>
4385
4386<p>
4387The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4388the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4389specifying the number of bytes to copy, and the fourth argument is the alignment
4390of the source and destination locations.
4391</p>
4392
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4393<p>
4394If 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]4395the caller guarantees that the source and destination pointers are aligned to
4396that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]4397</p>
4398
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4399<h5>Semantics:</h5>
4400
4401<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4402The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]4403location to the destination location, which may overlap. It
4404copies "len" bytes of memory over. If the argument is known to be aligned to
4405some boundary, this can be specified as the fourth argument, otherwise it should
4406be set to 0 or 1.
4407</p>
4408</div>
4409
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4410
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4411<!-- _______________________________________________________________________ -->
4412<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4413 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4414</div>
4415
4416<div class="doc_text">
4417
4418<h5>Syntax:</h5>
4419<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4420 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4421 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4422 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4423 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4424</pre>
4425
4426<h5>Overview:</h5>
4427
4428<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4429The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4430byte value.
4431</p>
4432
4433<p>
4434Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
4435does not return a value, and takes an extra alignment argument.
4436</p>
4437
4438<h5>Arguments:</h5>
4439
4440<p>
4441The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4442byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4443argument specifying the number of bytes to fill, and the fourth argument is the
4444known alignment of destination location.
4445</p>
4446
4447<p>
4448If 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]4449the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4450</p>
4451
4452<h5>Semantics:</h5>
4453
4454<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +0000[diff] [blame]4455The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
4456the
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]4457destination location. If the argument is known to be aligned to some boundary,
4458this can be specified as the fourth argument, otherwise it should be set to 0 or
44591.
4460</p>
4461</div>
4462
4463
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4464<!-- _______________________________________________________________________ -->
4465<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4466 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4467</div>
4468
4469<div class="doc_text">
4470
4471<h5>Syntax:</h5>
4472<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4473 declare float @llvm.sqrt.f32(float %Val)
4474 declare double @llvm.sqrt.f64(double %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4475</pre>
4476
4477<h5>Overview:</h5>
4478
4479<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4480The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4481returning the same value as the libm '<tt>sqrt</tt>' function would. Unlike
4482<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
4483negative numbers (which allows for better optimization).
4484</p>
4485
4486<h5>Arguments:</h5>
4487
4488<p>
4489The argument and return value are floating point numbers of the same type.
4490</p>
4491
4492<h5>Semantics:</h5>
4493
4494<p>
Dan Gohman33988db2007-07-16 14:37:41 +0000[diff] [blame]4495This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]4496floating point number.
4497</p>
4498</div>
4499
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4500<!-- _______________________________________________________________________ -->
4501<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4502 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4503</div>
4504
4505<div class="doc_text">
4506
4507<h5>Syntax:</h5>
4508<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4509 declare float @llvm.powi.f32(float %Val, i32 %power)
4510 declare double @llvm.powi.f64(double %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]4511</pre>
4512
4513<h5>Overview:</h5>
4514
4515<p>
4516The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
4517specified (positive or negative) power. The order of evaluation of
4518multiplications is not defined.
4519</p>
4520
4521<h5>Arguments:</h5>
4522
4523<p>
4524The second argument is an integer power, and the first is a value to raise to
4525that power.
4526</p>
4527
4528<h5>Semantics:</h5>
4529
4530<p>
4531This function returns the first value raised to the second power with an
4532unspecified sequence of rounding operations.</p>
4533</div>
4534
4535
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4536<!-- ======================================================================= -->
4537<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4538 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4539</div>
4540
4541<div class="doc_text">
4542<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4543LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4544These allow efficient code generation for some algorithms.
4545</p>
4546
4547</div>
4548
4549<!-- _______________________________________________________________________ -->
4550<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4551 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4552</div>
4553
4554<div class="doc_text">
4555
4556<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4557<p>This is an overloaded intrinsic function. You can use bswap on any integer
4558type that is an even number of bytes (i.e. BitWidth % 16 == 0). Note the suffix
4559that includes the type for the result and the operand.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4560<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4561 declare i16 @llvm.bswap.i16.i16(i16 &lt;id&gt;)
4562 declare i32 @llvm.bswap.i32.i32(i32 &lt;id&gt;)
Reid Spencer403a1c42007-04-02 00:19:52 +0000[diff] [blame]4563 declare i64 @llvm.bswap.i64.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4564</pre>
4565
4566<h5>Overview:</h5>
4567
4568<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +0000[diff] [blame]4569The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4570values with an even number of bytes (positive multiple of 16 bits). These are
4571useful for performing operations on data that is not in the target's native
4572byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4573</p>
4574
4575<h5>Semantics:</h5>
4576
4577<p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4578The <tt>llvm.bswap.16.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4579and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
4580intrinsic returns an i32 value that has the four bytes of the input i32
4581swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4582i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48.i48</tt>,
4583<tt>llvm.bswap.i64.i64</tt> and other intrinsics extend this concept to
4584additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]4585</p>
4586
4587</div>
4588
4589<!-- _______________________________________________________________________ -->
4590<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4591 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4592</div>
4593
4594<div class="doc_text">
4595
4596<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4597<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
4598width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4599<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4600 declare i32 @llvm.ctpop.i8 (i8 &lt;src&gt;)
4601 declare i32 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4602 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4603 declare i32 @llvm.ctpop.i64(i64 &lt;src&gt;)
4604 declare i32 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4605</pre>
4606
4607<h5>Overview:</h5>
4608
4609<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +0000[diff] [blame]4610The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
4611value.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4612</p>
4613
4614<h5>Arguments:</h5>
4615
4616<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4617The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4618integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4619</p>
4620
4621<h5>Semantics:</h5>
4622
4623<p>
4624The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
4625</p>
4626</div>
4627
4628<!-- _______________________________________________________________________ -->
4629<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4630 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4631</div>
4632
4633<div class="doc_text">
4634
4635<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4636<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
4637integer bit width. Not all targets support all bit widths however.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4638<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4639 declare i32 @llvm.ctlz.i8 (i8 &lt;src&gt;)
4640 declare i32 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4641 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4642 declare i32 @llvm.ctlz.i64(i64 &lt;src&gt;)
4643 declare i32 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4644</pre>
4645
4646<h5>Overview:</h5>
4647
4648<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4649The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
4650leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4651</p>
4652
4653<h5>Arguments:</h5>
4654
4655<p>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]4656The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4657integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4658</p>
4659
4660<h5>Semantics:</h5>
4661
4662<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4663The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
4664in 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]4665of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]4666</p>
4667</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]4668
4669
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4670
4671<!-- _______________________________________________________________________ -->
4672<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]4673 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4674</div>
4675
4676<div class="doc_text">
4677
4678<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4679<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
4680integer bit width. Not all targets support all bit widths however.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4681<pre>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4682 declare i32 @llvm.cttz.i8 (i8 &lt;src&gt;)
4683 declare i32 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]4684 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]4685 declare i32 @llvm.cttz.i64(i64 &lt;src&gt;)
4686 declare i32 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4687</pre>
4688
4689<h5>Overview:</h5>
4690
4691<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]4692The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
4693trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4694</p>
4695
4696<h5>Arguments:</h5>
4697
4698<p>
4699The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +0000[diff] [blame]4700integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]4701</p>
4702
4703<h5>Semantics:</h5>
4704
4705<p>
4706The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
4707in a variable. If the src == 0 then the result is the size in bits of the type
4708of src. For example, <tt>llvm.cttz(2) = 1</tt>.
4709</p>
4710</div>
4711
Reid Spencer8a5799f2007-04-01 08:27:01 +0000[diff] [blame]4712<!-- _______________________________________________________________________ -->
4713<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4714 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4715</div>
4716
4717<div class="doc_text">
4718
4719<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4720<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4721on any integer bit width.
4722<pre>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4723 declare i17 @llvm.part.select.i17.i17 (i17 %val, i32 %loBit, i32 %hiBit)
4724 declare i29 @llvm.part.select.i29.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4725</pre>
4726
4727<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4728<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4729range of bits from an integer value and returns them in the same bit width as
4730the original value.</p>
4731
4732<h5>Arguments:</h5>
4733<p>The first argument, <tt>%val</tt> and the result may be integer types of
4734any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4735arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4736
4737<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +0000[diff] [blame]4738<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]4739of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
4740<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
4741operates in forward mode.</p>
4742<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
4743right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4744only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
4745<ol>
4746 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
4747 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
4748 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
4749 to determine the number of bits to retain.</li>
4750 <li>A mask of the retained bits is created by shifting a -1 value.</li>
4751 <li>The mask is ANDed with <tt>%val</tt> to produce the result.
4752</ol>
Reid Spencer70845c02007-05-14 16:14:57 +0000[diff] [blame]4753<p>In reverse mode, a similar computation is made except that the bits are
4754returned in the reverse order. So, for example, if <tt>X</tt> has the value
4755<tt>i16 0x0ACF (101011001111)</tt> and we apply
4756<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
4757<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +0000[diff] [blame]4758</div>
4759
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4760<div class="doc_subsubsection">
4761 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
4762</div>
4763
4764<div class="doc_text">
4765
4766<h5>Syntax:</h5>
4767<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
4768on any integer bit width.
4769<pre>
4770 declare i17 @llvm.part.set.i17.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
4771 declare i29 @llvm.part.set.i29.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
4772</pre>
4773
4774<h5>Overview:</h5>
4775<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
4776of bits in an integer value with another integer value. It returns the integer
4777with the replaced bits.</p>
4778
4779<h5>Arguments:</h5>
4780<p>The first argument, <tt>%val</tt> and the result may be integer types of
4781any bit width but they must have the same bit width. <tt>%val</tt> is the value
4782whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
4783integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
4784type since they specify only a bit index.</p>
4785
4786<h5>Semantics:</h5>
4787<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
4788of operation: forwards and reverse. If <tt>%lo</tt> is greater than
4789<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
4790operates in forward mode.</p>
4791<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
4792truncating it down to the size of the replacement area or zero extending it
4793up to that size.</p>
4794<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
4795are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
4796in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
4797to the <tt>%hi</tt>th bit.
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]4798<p>In reverse mode, a similar computation is made except that the bits are
4799reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
4800<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4801<h5>Examples:</h5>
4802<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]4803 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +0000[diff] [blame]4804 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
4805 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
4806 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +0000[diff] [blame]4807 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]4808</pre>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]4809</div>
4810
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]4811<!-- ======================================================================= -->
4812<div class="doc_subsection">
4813 <a name="int_debugger">Debugger Intrinsics</a>
4814</div>
4815
4816<div class="doc_text">
4817<p>
4818The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
4819are described in the <a
4820href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
4821Debugging</a> document.
4822</p>
4823</div>
4824
4825
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]4826<!-- ======================================================================= -->
4827<div class="doc_subsection">
4828 <a name="int_eh">Exception Handling Intrinsics</a>
4829</div>
4830
4831<div class="doc_text">
4832<p> The LLVM exception handling intrinsics (which all start with
4833<tt>llvm.eh.</tt> prefix), are described in the <a
4834href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
4835Handling</a> document. </p>
4836</div>
4837
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]4838<!-- ======================================================================= -->
4839<div class="doc_subsection">
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4840 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
4841</div>
4842
4843<div class="doc_text">
4844<p>
4845 These intrinsic functions expand the "universal IR" of LLVM to represent
4846 hardware constructs for atomic operations and memory synchronization. This
4847 provides an interface to the hardware, not an interface to the programmer. It
4848 is aimed at a low enough level to allow any programming models or APIs which
4849 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4850 hardware behavior. Just as hardware provides a "universal IR" for source
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4851 languages, it also provides a starting point for developing a "universal"
4852 atomic operation and synchronization IR.
4853</p>
4854<p>
4855 These do <em>not</em> form an API such as high-level threading libraries,
4856 software transaction memory systems, atomic primitives, and intrinsic
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4857 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4858 application libraries. The hardware interface provided by LLVM should allow
4859 a clean implementation of all of these APIs and parallel programming models.
4860 No one model or paradigm should be selected above others unless the hardware
4861 itself ubiquitously does so.
4862</p>
4863</div>
4864
4865<!-- _______________________________________________________________________ -->
4866<div class="doc_subsubsection">
4867 <a name="int_lcs">'<tt>llvm.atomic.lcs.*</tt>' Intrinsic</a>
4868</div>
4869<div class="doc_text">
4870<h5>Syntax:</h5>
4871<p>
4872 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lcs</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4873 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4874<pre>
4875declare i8 @llvm.atomic.lcs.i8.i8p.i8.i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
4876declare i16 @llvm.atomic.lcs.i16.i16p.i16.i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
4877declare i32 @llvm.atomic.lcs.i32.i32p.i32.i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
4878declare i64 @llvm.atomic.lcs.i64.i64p.i64.i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
4879</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4880<h5>Overview:</h5>
4881<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4882 This loads a value in memory and compares it to a given value. If they are
4883 equal, it stores a new value into the memory.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4884</p>
4885<h5>Arguments:</h5>
4886<p>
4887 The <tt>llvm.atomic.lcs</tt> intrinsic takes three arguments. The result as
4888 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
4889 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
4890 this integer type. While any bit width integer may be used, targets may only
4891 lower representations they support in hardware.
4892</p>
4893<h5>Semantics:</h5>
4894<p>
4895 This entire intrinsic must be executed atomically. It first loads the value
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4896 in memory pointed to by <tt>ptr</tt> and compares it with the value
4897 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
4898 loaded value is yielded in all cases. This provides the equivalent of an
4899 atomic compare-and-swap operation within the SSA framework.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4900</p>
4901<h5>Examples:</h5>
4902<pre>
4903%ptr = malloc i32
4904 store i32 4, %ptr
4905
4906%val1 = add i32 4, 4
4907%result1 = call i32 @llvm.atomic.lcs( i32* %ptr, i32 4, %val1 )
4908 <i>; yields {i32}:result1 = 4</i>
4909%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
4910%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
4911
4912%val2 = add i32 1, 1
4913%result2 = call i32 @llvm.atomic.lcs( i32* %ptr, i32 5, %val2 )
4914 <i>; yields {i32}:result2 = 8</i>
4915%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
4916%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
4917</pre>
4918</div>
4919
4920<!-- _______________________________________________________________________ -->
4921<div class="doc_subsubsection">
4922 <a name="int_ls">'<tt>llvm.atomic.ls.*</tt>' Intrinsic</a>
4923</div>
4924<div class="doc_text">
4925<h5>Syntax:</h5>
4926<p>
4927 This is an overloaded intrinsic. You can use <tt>llvm.atomic.ls</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4928 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4929<pre>
4930declare i8 @llvm.atomic.ls.i8.i8p.i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
4931declare i16 @llvm.atomic.ls.i16.i16p.i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
4932declare i32 @llvm.atomic.ls.i32.i32p.i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
4933declare i64 @llvm.atomic.ls.i64.i64p.i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
4934</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4935<h5>Overview:</h5>
4936<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4937 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
4938 the value from memory. It then stores the value in <tt>val</tt> in the memory
4939 at <tt>ptr</tt>.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4940</p>
4941<h5>Arguments:</h5>
4942<p>
4943 The <tt>llvm.atomic.ls</tt> intrinsic takes two arguments. Both the
4944 <tt>val</tt> argument and the result must be integers of the same bit width.
4945 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
4946 integer type. The targets may only lower integer representations they
4947 support.
4948</p>
4949<h5>Semantics:</h5>
4950<p>
4951 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
4952 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
4953 equivalent of an atomic swap operation within the SSA framework.
4954</p>
4955<h5>Examples:</h5>
4956<pre>
4957%ptr = malloc i32
4958 store i32 4, %ptr
4959
4960%val1 = add i32 4, 4
4961%result1 = call i32 @llvm.atomic.ls( i32* %ptr, i32 %val1 )
4962 <i>; yields {i32}:result1 = 4</i>
4963%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
4964%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
4965
4966%val2 = add i32 1, 1
4967%result2 = call i32 @llvm.atomic.ls( i32* %ptr, i32 %val2 )
4968 <i>; yields {i32}:result2 = 8</i>
4969%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
4970%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
4971</pre>
4972 </div>
4973
4974<!-- _______________________________________________________________________ -->
4975<div class="doc_subsubsection">
4976 <a name="int_las">'<tt>llvm.atomic.las.*</tt>' Intrinsic</a>
4977</div>
4978<div class="doc_text">
4979<h5>Syntax:</h5>
4980<p>
4981 This is an overloaded intrinsic. You can use <tt>llvm.atomic.las</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]4982 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4983<pre>
4984declare i8 @llvm.atomic.las.i8.i8p.i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
4985declare i16 @llvm.atomic.las.i16.i16p.i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
4986declare i32 @llvm.atomic.las.i32.i32p.i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
4987declare i64 @llvm.atomic.las.i64.i64p.i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
4988</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4989<h5>Overview:</h5>
4990<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]4991 This intrinsic adds <tt>delta</tt> to the value stored in memory at
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]4992 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
4993</p>
4994<h5>Arguments:</h5>
4995<p>
4996 The intrinsic takes two arguments, the first a pointer to an integer value
4997 and the second an integer value. The result is also an integer value. These
4998 integer types can have any bit width, but they must all have the same bit
4999 width. The targets may only lower integer representations they support.
5000</p>
5001<h5>Semantics:</h5>
5002<p>
5003 This intrinsic does a series of operations atomically. It first loads the
5004 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
5005 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
5006</p>
5007<h5>Examples:</h5>
5008<pre>
5009%ptr = malloc i32
5010 store i32 4, %ptr
5011%result1 = call i32 @llvm.atomic.las( i32* %ptr, i32 4 )
5012 <i>; yields {i32}:result1 = 4</i>
5013%result2 = call i32 @llvm.atomic.las( i32* %ptr, i32 2 )
5014 <i>; yields {i32}:result2 = 8</i>
5015%result3 = call i32 @llvm.atomic.las( i32* %ptr, i32 5 )
5016 <i>; yields {i32}:result3 = 10</i>
5017%memval = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
5018</pre>
5019</div>
5020
5021<!-- _______________________________________________________________________ -->
5022<div class="doc_subsubsection">
5023 <a name="int_lss">'<tt>llvm.atomic.lss.*</tt>' Intrinsic</a>
5024</div>
5025<div class="doc_text">
5026<h5>Syntax:</h5>
5027<p>
5028 This is an overloaded intrinsic. You can use <tt>llvm.atomic.lss</tt> on any
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]5029 integer bit width. Not all targets support all bit widths however.</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5030<pre>
5031declare i8 @llvm.atomic.lss.i8.i8.i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
5032declare i16 @llvm.atomic.lss.i16.i16.i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
5033declare i32 @llvm.atomic.lss.i32.i32.i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
5034declare i64 @llvm.atomic.lss.i64.i64.i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
5035</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5036<h5>Overview:</h5>
5037<p>
Chandler Carruthfd4184352007-07-20 20:14:52 +0000[diff] [blame]5038 This intrinsic subtracts <tt>delta</tt> from the value stored in memory at
5039 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5040</p>
5041<h5>Arguments:</h5>
5042<p>
5043 The intrinsic takes two arguments, the first a pointer to an integer value
5044 and the second an integer value. The result is also an integer value. These
5045 integer types can have any bit width, but they must all have the same bit
5046 width. The targets may only lower integer representations they support.
5047</p>
5048<h5>Semantics:</h5>
5049<p>
5050 This intrinsic does a series of operations atomically. It first loads the
5051 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>,
5052 stores the result to <tt>ptr</tt>. It yields the original value stored
5053 at <tt>ptr</tt>.
5054</p>
5055<h5>Examples:</h5>
5056<pre>
5057%ptr = malloc i32
5058 store i32 32, %ptr
5059%result1 = call i32 @llvm.atomic.lss( i32* %ptr, i32 4 )
5060 <i>; yields {i32}:result1 = 32</i>
5061%result2 = call i32 @llvm.atomic.lss( i32* %ptr, i32 2 )
5062 <i>; yields {i32}:result2 = 28</i>
5063%result3 = call i32 @llvm.atomic.lss( i32* %ptr, i32 5 )
5064 <i>; yields {i32}:result3 = 26</i>
5065%memval = load i32* %ptr <i>; yields {i32}:memval1 = 21</i>
5066</pre>
5067</div>
5068
5069<!-- _______________________________________________________________________ -->
5070<div class="doc_subsubsection">
5071 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
5072</div>
5073<div class="doc_text">
5074<h5>Syntax:</h5>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5075<pre>
5076declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt; )
5077</pre>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5078<h5>Overview:</h5>
5079<p>
5080 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
5081 specific pairs of memory access types.
5082</p>
5083<h5>Arguments:</h5>
5084<p>
5085 The <tt>llvm.memory.barrier</tt> intrinsic requires four boolean arguments.
5086 Each argument enables a specific barrier as listed below.
Reid Spencer65a72e32007-07-20 20:03:33 +0000[diff] [blame]5087</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5088 <ul>
5089 <li><tt>ll</tt>: load-load barrier</li>
5090 <li><tt>ls</tt>: load-store barrier</li>
5091 <li><tt>sl</tt>: store-load barrier</li>
5092 <li><tt>ss</tt>: store-store barrier</li>
5093 </ul>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5094<h5>Semantics:</h5>
5095<p>
5096 This intrinsic causes the system to enforce some ordering constraints upon
5097 the loads and stores of the program. This barrier does not indicate
5098 <em>when</em> any events will occur, it only enforces an <em>order</em> in
5099 which they occur. For any of the specified pairs of load and store operations
5100 (f.ex. load-load, or store-load), all of the first operations preceding the
5101 barrier will complete before any of the second operations succeeding the
5102 barrier begin. Specifically the semantics for each pairing is as follows:
Reid Spencer65a72e32007-07-20 20:03:33 +0000[diff] [blame]5103</p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5104 <ul>
5105 <li><tt>ll</tt>: All loads before the barrier must complete before any load
5106 after the barrier begins.</li>
5107 <li><tt>ls</tt>: All loads before the barrier must complete before any
5108 store after the barrier begins.</li>
5109 <li><tt>ss</tt>: All stores before the barrier must complete before any
5110 store after the barrier begins.</li>
5111 <li><tt>sl</tt>: All stores before the barrier must complete before any
5112 load after the barrier begins.</li>
5113 </ul>
Reid Spencer65a72e32007-07-20 20:03:33 +0000[diff] [blame]5114<p>
Chandler Carruth6a5f6bf62007-07-20 19:34:37 +0000[diff] [blame]5115 These semantics are applied with a logical "and" behavior when more than one
5116 is enabled in a single memory barrier intrinsic.
5117</p>
5118<h5>Example:</h5>
5119<pre>
5120%ptr = malloc i32
5121 store i32 4, %ptr
5122
5123%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
5124 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
5125 <i>; guarantee the above finishes</i>
5126 store i32 8, %ptr <i>; before this begins</i>
5127</pre>
5128</div>
5129
5130<!-- ======================================================================= -->
5131<div class="doc_subsection">
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame^]5132 <a name="int_trampoline">Trampoline Intrinsics</a>
5133</div>
5134
5135<div class="doc_text">
5136<p>
5137 These intrinsics make it possible to excise one parameter, marked with
5138 the <tt>nest</tt> attribute, from a function. The result is a callable
5139 function pointer lacking the nest parameter - the caller does not need
5140 to provide a value for it. Instead, the value to use is stored in
5141 advance in a "trampoline", a block of memory usually allocated
5142 on the stack, which also contains code to splice the nest value into the
5143 argument list. This is used to implement the GCC nested function address
5144 extension.
5145</p>
5146<p>
5147 For example, if the function is
5148 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
5149 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:
5150<pre>
5151 %tramp1 = alloca [10 x i8], align 4 ; size and alignment only correct for X86
5152 %tramp = getelementptr [10 x i8]* %tramp1, i32 0, i32 0
5153 call void @llvm.init.trampoline( i8* %tramp, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
5154 %adj = call i8* @llvm.adjust.trampoline( i8* %tramp )
5155 %fp = bitcast i8* %adj to i32 (i32, i32)*
5156</pre>
5157 The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent to
5158 <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.
5159</p>
5160<p>
5161 Trampolines are currently only supported on the X86 architecture.
5162</p>
5163</div>
5164
5165<!-- _______________________________________________________________________ -->
5166<div class="doc_subsubsection">
5167 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
5168</div>
5169<div class="doc_text">
5170<h5>Syntax:</h5>
5171<pre>
5172declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
5173</pre>
5174<h5>Overview:</h5>
5175<p>
5176 This initializes the memory pointed to by <tt>tramp</tt> as a trampoline.
5177</p>
5178<h5>Arguments:</h5>
5179<p>
5180 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
5181 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
5182 and sufficiently aligned block of memory; this memory is written to by the
5183 intrinsic. Currently LLVM provides no help in determining just how big and
5184 aligned the memory needs to be. The <tt>func</tt> argument must hold a
5185 function bitcast to an <tt>i8*</tt>.
5186</p>
5187<h5>Semantics:</h5>
5188<p>
5189 The block of memory pointed to by <tt>tramp</tt> is filled with target
5190 dependent code, turning it into a function.
5191 The new function's signature is the same as that of <tt>func</tt> with
5192 any arguments marked with the <tt>nest</tt> attribute removed. At most
5193 one such <tt>nest</tt> argument is allowed, and it must be of pointer
5194 type. Calling the new function is equivalent to calling <tt>func</tt>
5195 with the same argument list, but with <tt>nval</tt> used for the missing
5196 <tt>nest</tt> argument.
5197</p>
5198</div>
5199
5200<!-- _______________________________________________________________________ -->
5201<div class="doc_subsubsection">
5202 <a name="int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a>
5203</div>
5204<div class="doc_text">
5205<h5>Syntax:</h5>
5206<pre>
5207declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
5208</pre>
5209<h5>Overview:</h5>
5210<p>
5211 This intrinsic returns a function pointer suitable for executing
5212 the trampoline code pointed to by <tt>tramp</tt>.
5213</p>
5214<h5>Arguments:</h5>
5215<p>
5216 The <tt>llvm.adjust.trampoline</tt> takes one argument, a pointer to a
5217 trampoline initialized by the
5218 <a href="#int_it">'<tt>llvm.init.trampoline</tt>' intrinsic</a>.
5219</p>
5220<h5>Semantics:</h5>
5221<p>
5222 A function pointer that can be used to execute the trampoline code in
5223 <tt>tramp</tt> is returned. The returned value should be bitcast to an
5224 <a href="#int_trampoline">appropriate function pointer type</a>
5225 before being called.
5226</p>
5227</div>
5228
5229<!-- ======================================================================= -->
5230<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5231 <a name="int_general">General Intrinsics</a>
5232</div>
5233
5234<div class="doc_text">
5235<p> This class of intrinsics is designed to be generic and has
5236no specific purpose. </p>
5237</div>
5238
5239<!-- _______________________________________________________________________ -->
5240<div class="doc_subsubsection">
5241 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
5242</div>
5243
5244<div class="doc_text">
5245
5246<h5>Syntax:</h5>
5247<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5248 declare void @llvm.var.annotation(i8* &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5249</pre>
5250
5251<h5>Overview:</h5>
5252
5253<p>
5254The '<tt>llvm.var.annotation</tt>' intrinsic
5255</p>
5256
5257<h5>Arguments:</h5>
5258
5259<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +0000[diff] [blame]5260The first argument is a pointer to a value, the second is a pointer to a
5261global string, the third is a pointer to a global string which is the source
5262file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]5263</p>
5264
5265<h5>Semantics:</h5>
5266
5267<p>
5268This intrinsic allows annotation of local variables with arbitrary strings.
5269This can be useful for special purpose optimizations that want to look for these
5270 annotations. These have no other defined use, they are ignored by code
5271 generation and optimization.
5272</div>
5273
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]5274
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5275<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5276<hr>
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5282
5283 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +0000[diff] [blame]5284 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
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