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gerrit-public.fairphone.software / toolchain / llvm-project / 911fdf47cda1a5a6278430a3cdfffe0d1ff23a2b / . / 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">
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Reid Spencercb84e432004-08-26 20:44:00 +0000[diff] [blame]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
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]15<h1>LLVM Language Reference Manual</h1>
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>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]23 <li><a href="#linkage">Linkage Types</a>
24 <ol>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]25 <li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
26 <li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]27 <li><a href="#linkage_linker_private_weak">'<tt>linker_private_weak</tt>' Linkage</a></li>
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]28 <li><a href="#linkage_linker_private_weak_def_auto">'<tt>linker_private_weak_def_auto</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]29 <li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
30 <li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
31 <li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
32 <li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
33 <li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
34 <li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
35 <li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
Chris Lattner80d73c72009-10-10 18:26:06 +0000[diff] [blame]36 <li><a href="#linkage_linkonce_odr">'<tt>linkonce_odr</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]37 <li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]38 <li><a href="#linkage_external">'<tt>external</tt>' Linkage</a></li>
Bill Wendling8693ef82009-07-20 02:41:50 +0000[diff] [blame]39 <li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
40 <li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]41 </ol>
42 </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]43 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]44 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]45 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]46 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]47 <li><a href="#aliasstructure">Aliases</a></li>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]48 <li><a href="#namedmetadatastructure">Named Metadata</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]49 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]50 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]51 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]52 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]53 <li><a href="#datalayout">Data Layout</a></li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]54 <li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]55 <li><a href="#volatile">Volatile Memory Accesses</a></li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]56 <li><a href="#memmodel">Memory Model for Concurrent Operations</a></li>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]57 <li><a href="#ordering">Atomic Memory Ordering Constraints</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]58 </ol>
59 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]60 <li><a href="#typesystem">Type System</a>
61 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]62 <li><a href="#t_classifications">Type Classifications</a></li>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]63 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]64 <ol>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]65 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]66 <li><a href="#t_floating">Floating Point Types</a></li>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]67 <li><a href="#t_x86mmx">X86mmx Type</a></li>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]68 <li><a href="#t_void">Void Type</a></li>
69 <li><a href="#t_label">Label Type</a></li>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]70 <li><a href="#t_metadata">Metadata Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]71 </ol>
72 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]73 <li><a href="#t_derived">Derived Types</a>
74 <ol>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]75 <li><a href="#t_aggregate">Aggregate Types</a>
76 <ol>
77 <li><a href="#t_array">Array Type</a></li>
78 <li><a href="#t_struct">Structure Type</a></li>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]79 <li><a href="#t_opaque">Opaque Structure Types</a></li>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]80 <li><a href="#t_vector">Vector Type</a></li>
81 </ol>
82 </li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]83 <li><a href="#t_function">Function Type</a></li>
84 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]85 </ol>
86 </li>
87 </ol>
88 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]89 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]90 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]91 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]92 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]93 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
94 <li><a href="#undefvalues">Undefined Values</a></li>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]95 <li><a href="#poisonvalues">Poison Values</a></li>
Chris Lattner2bfd3202009-10-27 21:19:13 +0000[diff] [blame]96 <li><a href="#blockaddress">Addresses of Basic Blocks</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]97 <li><a href="#constantexprs">Constant Expressions</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]98 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]99 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]100 <li><a href="#othervalues">Other Values</a>
101 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]102 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]103 <li><a href="#metadata">Metadata Nodes and Metadata Strings</a>
104 <ol>
105 <li><a href="#tbaa">'<tt>tbaa</tt>' Metadata</a></li>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]106 <li><a href="#fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a></li>
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]107 </ol>
108 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]109 </ol>
110 </li>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame^]111 <li><a href="#module_flags">Module Flags Metadata</a>
112 <ol>
113 </ol>
114 </li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]115 <li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
116 <ol>
117 <li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]118 <li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
119 Global Variable</a></li>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]120 <li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
121 Global Variable</a></li>
122 <li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
123 Global Variable</a></li>
124 </ol>
125 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]126 <li><a href="#instref">Instruction Reference</a>
127 <ol>
128 <li><a href="#terminators">Terminator Instructions</a>
129 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]130 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
131 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]132 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]133 <li><a href="#i_indirectbr">'<tt>indirectbr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]134 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]135 <li><a href="#i_resume">'<tt>resume</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]136 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]137 </ol>
138 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]139 <li><a href="#binaryops">Binary Operations</a>
140 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]141 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]142 <li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]143 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]144 <li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]145 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]146 <li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]147 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
148 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
149 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]150 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
151 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
152 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]153 </ol>
154 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]155 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
156 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]157 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
158 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
159 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]160 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]161 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]162 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]163 </ol>
164 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]165 <li><a href="#vectorops">Vector Operations</a>
166 <ol>
167 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
168 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
169 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]170 </ol>
171 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]172 <li><a href="#aggregateops">Aggregate Operations</a>
173 <ol>
174 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
175 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
176 </ol>
177 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]178 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]179 <ol>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]180 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
181 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
182 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
183 <li><a href="#i_fence">'<tt>fence</tt>' Instruction</a></li>
184 <li><a href="#i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a></li>
185 <li><a href="#i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]186 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]187 </ol>
188 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]189 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]190 <ol>
191 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
192 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
193 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
194 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
195 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]196 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
197 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
198 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
199 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]200 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
201 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]202 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]203 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]204 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]205 <li><a href="#otherops">Other Operations</a>
206 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]207 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
208 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]209 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]210 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]211 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]212 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]213 <li><a href="#i_landingpad">'<tt>landingpad</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]214 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]215 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]216 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]217 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]218 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]219 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]220 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
221 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]222 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
223 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
224 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]225 </ol>
226 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]227 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
228 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]229 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
230 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
231 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]232 </ol>
233 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]234 <li><a href="#int_codegen">Code Generator Intrinsics</a>
235 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]236 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
237 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
238 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
239 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
240 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
241 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
Dan Gohmane58f7b32010-05-26 21:56:15 +0000[diff] [blame]242 <li><a href="#int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000[diff] [blame]243 </ol>
244 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]245 <li><a href="#int_libc">Standard C Library Intrinsics</a>
246 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]247 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
248 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
249 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
250 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
251 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]252 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
253 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
254 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohmane635c522011-05-27 00:36:31 +0000[diff] [blame]255 <li><a href="#int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a></li>
256 <li><a href="#int_log">'<tt>llvm.log.*</tt>' Intrinsic</a></li>
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]257 <li><a href="#int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]258 </ol>
259 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]260 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]261 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]262 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]263 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
264 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
265 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]266 </ol>
267 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]268 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
269 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]270 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
271 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
272 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
273 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
274 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]275 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]276 </ol>
277 </li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]278 <li><a href="#int_fp16">Half Precision Floating Point Intrinsics</a>
279 <ol>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]280 <li><a href="#int_convert_to_fp16">'<tt>llvm.convert.to.fp16</tt>' Intrinsic</a></li>
281 <li><a href="#int_convert_from_fp16">'<tt>llvm.convert.from.fp16</tt>' Intrinsic</a></li>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]282 </ol>
283 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]284 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]285 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]286 <li><a href="#int_trampoline">Trampoline Intrinsics</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]287 <ol>
288 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]289 <li><a href="#int_at">'<tt>llvm.adjust.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]290 </ol>
291 </li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]292 <li><a href="#int_memorymarkers">Memory Use Markers</a>
293 <ol>
Jakub Staszak5fd147f2011-12-04 20:44:25 +0000[diff] [blame]294 <li><a href="#int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a></li>
295 <li><a href="#int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a></li>
296 <li><a href="#int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a></li>
297 <li><a href="#int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a></li>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]298 </ol>
299 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]300 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]301 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000[diff] [blame]302 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]303 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]304 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]305 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]306 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]307 '<tt>llvm.trap</tt>' Intrinsic</a></li>
308 <li><a href="#int_stackprotector">
309 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]310 <li><a href="#int_objectsize">
311 '<tt>llvm.objectsize</tt>' Intrinsic</a></li>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]312 <li><a href="#int_expect">
313 '<tt>llvm.expect</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]314 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]315 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]316 </ol>
317 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]318</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]319
320<div class="doc_author">
321 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
322 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]323</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]324
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]325<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]326<h2><a name="abstract">Abstract</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]327<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]328
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]329<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]330
331<p>This document is a reference manual for the LLVM assembly language. LLVM is
332 a Static Single Assignment (SSA) based representation that provides type
333 safety, low-level operations, flexibility, and the capability of representing
334 'all' high-level languages cleanly. It is the common code representation
335 used throughout all phases of the LLVM compilation strategy.</p>
336
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]337</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]338
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]339<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]340<h2><a name="introduction">Introduction</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]341<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]342
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]343<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]344
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]345<p>The LLVM code representation is designed to be used in three different forms:
346 as an in-memory compiler IR, as an on-disk bitcode representation (suitable
347 for fast loading by a Just-In-Time compiler), and as a human readable
348 assembly language representation. This allows LLVM to provide a powerful
349 intermediate representation for efficient compiler transformations and
350 analysis, while providing a natural means to debug and visualize the
351 transformations. The three different forms of LLVM are all equivalent. This
352 document describes the human readable representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]353
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]354<p>The LLVM representation aims to be light-weight and low-level while being
355 expressive, typed, and extensible at the same time. It aims to be a
356 "universal IR" of sorts, by being at a low enough level that high-level ideas
357 may be cleanly mapped to it (similar to how microprocessors are "universal
358 IR's", allowing many source languages to be mapped to them). By providing
359 type information, LLVM can be used as the target of optimizations: for
360 example, through pointer analysis, it can be proven that a C automatic
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]361 variable is never accessed outside of the current function, allowing it to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]362 be promoted to a simple SSA value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]363
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]364<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]365<h4>
366 <a name="wellformed">Well-Formedness</a>
367</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]368
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]369<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]370
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]371<p>It is important to note that this document describes 'well formed' LLVM
372 assembly language. There is a difference between what the parser accepts and
373 what is considered 'well formed'. For example, the following instruction is
374 syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]375
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]376<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]377%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]378</pre>
379
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]380<p>because the definition of <tt>%x</tt> does not dominate all of its uses. The
381 LLVM infrastructure provides a verification pass that may be used to verify
382 that an LLVM module is well formed. This pass is automatically run by the
383 parser after parsing input assembly and by the optimizer before it outputs
384 bitcode. The violations pointed out by the verifier pass indicate bugs in
385 transformation passes or input to the parser.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]386
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]387</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]388
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]389</div>
390
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000[diff] [blame]391<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]392
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]393<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]394<h2><a name="identifiers">Identifiers</a></h2>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]395<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]396
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]397<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]398
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]399<p>LLVM identifiers come in two basic types: global and local. Global
400 identifiers (functions, global variables) begin with the <tt>'@'</tt>
401 character. Local identifiers (register names, types) begin with
402 the <tt>'%'</tt> character. Additionally, there are three different formats
403 for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]404
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]405<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]406 <li>Named values are represented as a string of characters with their prefix.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]407 For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
408 <tt>%a.really.long.identifier</tt>. The actual regular expression used is
409 '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
410 other characters in their names can be surrounded with quotes. Special
411 characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
412 ASCII code for the character in hexadecimal. In this way, any character
413 can be used in a name value, even quotes themselves.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]414
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]415 <li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]416 prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]417
Reid Spencer8f08d802004-12-09 18:02:53 +0000[diff] [blame]418 <li>Constants, which are described in a <a href="#constants">section about
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]419 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]420</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]421
Reid Spencerb23b65f2007-08-07 14:34:28 +0000[diff] [blame]422<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]423 don't need to worry about name clashes with reserved words, and the set of
424 reserved words may be expanded in the future without penalty. Additionally,
425 unnamed identifiers allow a compiler to quickly come up with a temporary
426 variable without having to avoid symbol table conflicts.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]427
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]428<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]429 languages. There are keywords for different opcodes
430 ('<tt><a href="#i_add">add</a></tt>',
431 '<tt><a href="#i_bitcast">bitcast</a></tt>',
432 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
433 ('<tt><a href="#t_void">void</a></tt>',
434 '<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
435 reserved words cannot conflict with variable names, because none of them
436 start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]437
438<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]439 '<tt>%X</tt>' by 8:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]440
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]441<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]442
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]443<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]444%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]445</pre>
446
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]447<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]448
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]449<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]450%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]451</pre>
452
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]453<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]454
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]455<pre class="doc_code">
Gabor Greifbd0328f2009-10-28 13:05:07 +0000[diff] [blame]456%0 = <a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
457%1 = <a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]458%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]459</pre>
460
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]461<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
462 lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]463
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]464<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]465 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]466 line.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]467
468 <li>Unnamed temporaries are created when the result of a computation is not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]469 assigned to a named value.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]470
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]471 <li>Unnamed temporaries are numbered sequentially</li>
472</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]473
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]474<p>It also shows a convention that we follow in this document. When
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]475 demonstrating instructions, we will follow an instruction with a comment that
476 defines the type and name of value produced. Comments are shown in italic
477 text.</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]478
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]479</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]480
481<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]482<h2><a name="highlevel">High Level Structure</a></h2>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]483<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]484<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]485<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]486<h3>
487 <a name="modulestructure">Module Structure</a>
488</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]489
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]490<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]491
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]492<p>LLVM programs are composed of "Module"s, each of which is a translation unit
493 of the input programs. Each module consists of functions, global variables,
494 and symbol table entries. Modules may be combined together with the LLVM
495 linker, which merges function (and global variable) definitions, resolves
496 forward declarations, and merges symbol table entries. Here is an example of
497 the "hello world" module:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]498
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]499<pre class="doc_code">
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]500<i>; Declare the string constant as a global constant.</i>&nbsp;
Nick Lewyckyfea7ddc2011-01-29 01:09:53 +0000[diff] [blame]501<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a>&nbsp;<a href="#globalvars">constant</a>&nbsp;<a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]502
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]503<i>; External declaration of the puts function</i>&nbsp;
504<a href="#functionstructure">declare</a> i32 @puts(i8*) <i>; i32 (i8*)* </i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]505
506<i>; Definition of main function</i>
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]507define i32 @main() { <i>; i32()* </i>&nbsp;
508 <i>; Convert [13 x i8]* to i8 *...</i>&nbsp;
509 %cast210 = <a href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8*</i>&nbsp;
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]510
Chris Lattner54a7be72010-08-17 17:13:42 +0000[diff] [blame]511 <i>; Call puts function to write out the string to stdout.</i>&nbsp;
512 <a href="#i_call">call</a> i32 @puts(i8* %cast210) <i>; i32</i>&nbsp;
513 <a href="#i_ret">ret</a> i32 0&nbsp;
514}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]515
516<i>; Named metadata</i>
517!1 = metadata !{i32 41}
518!foo = !{!1, null}
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]519</pre>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]520
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]521<p>This example is made up of a <a href="#globalvars">global variable</a> named
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]522 "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]523 a <a href="#functionstructure">function definition</a> for
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]524 "<tt>main</tt>" and <a href="#namedmetadatastructure">named metadata</a>
525 "<tt>foo"</tt>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]526
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]527<p>In general, a module is made up of a list of global values, where both
528 functions and global variables are global values. Global values are
529 represented by a pointer to a memory location (in this case, a pointer to an
530 array of char, and a pointer to a function), and have one of the
531 following <a href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]532
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]533</div>
534
535<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]536<h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]537 <a name="linkage">Linkage Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]538</h3>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]539
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]540<div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]541
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]542<p>All Global Variables and Functions have one of the following types of
543 linkage:</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]544
545<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]546 <dt><tt><b><a name="linkage_private">private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]547 <dd>Global values with "<tt>private</tt>" linkage are only directly accessible
548 by objects in the current module. In particular, linking code into a
549 module with an private global value may cause the private to be renamed as
550 necessary to avoid collisions. Because the symbol is private to the
551 module, all references can be updated. This doesn't show up in any symbol
552 table in the object file.</dd>
Rafael Espindola6de96a12009-01-15 20:18:42 +0000[diff] [blame]553
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]554 <dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt></dt>
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]555 <dd>Similar to <tt>private</tt>, but the symbol is passed through the
556 assembler and evaluated by the linker. Unlike normal strong symbols, they
557 are removed by the linker from the final linked image (executable or
558 dynamic library).</dd>
559
560 <dt><tt><b><a name="linkage_linker_private_weak">linker_private_weak</a></b></tt></dt>
561 <dd>Similar to "<tt>linker_private</tt>", but the symbol is weak. Note that
562 <tt>linker_private_weak</tt> symbols are subject to coalescing by the
563 linker. The symbols are removed by the linker from the final linked image
564 (executable or dynamic library).</dd>
Bill Wendlinga3c6f6b2009-07-20 01:03:30 +0000[diff] [blame]565
Bill Wendling578ee402010-08-20 22:05:50 +0000[diff] [blame]566 <dt><tt><b><a name="linkage_linker_private_weak_def_auto">linker_private_weak_def_auto</a></b></tt></dt>
567 <dd>Similar to "<tt>linker_private_weak</tt>", but it's known that the address
568 of the object is not taken. For instance, functions that had an inline
569 definition, but the compiler decided not to inline it. Note,
570 unlike <tt>linker_private</tt> and <tt>linker_private_weak</tt>,
571 <tt>linker_private_weak_def_auto</tt> may have only <tt>default</tt>
572 visibility. The symbols are removed by the linker from the final linked
573 image (executable or dynamic library).</dd>
574
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]575 <dt><tt><b><a name="linkage_internal">internal</a></b></tt></dt>
Bill Wendling36321712010-06-29 22:34:52 +0000[diff] [blame]576 <dd>Similar to private, but the value shows as a local symbol
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]577 (<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
578 corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]579
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]580 <dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt></dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]581 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]582 into the object file corresponding to the LLVM module. They exist to
583 allow inlining and other optimizations to take place given knowledge of
584 the definition of the global, which is known to be somewhere outside the
585 module. Globals with <tt>available_externally</tt> linkage are allowed to
586 be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
587 This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner184f1be2009-04-13 05:44:34 +0000[diff] [blame]588
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]589 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt></dt>
Chris Lattnere20b4702007-01-14 06:51:48 +0000[diff] [blame]590 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Chris Lattner0de4caa2010-01-09 19:15:14 +0000[diff] [blame]591 the same name when linkage occurs. This can be used to implement
592 some forms of inline functions, templates, or other code which must be
593 generated in each translation unit that uses it, but where the body may
594 be overridden with a more definitive definition later. Unreferenced
595 <tt>linkonce</tt> globals are allowed to be discarded. Note that
596 <tt>linkonce</tt> linkage does not actually allow the optimizer to
597 inline the body of this function into callers because it doesn't know if
598 this definition of the function is the definitive definition within the
599 program or whether it will be overridden by a stronger definition.
600 To enable inlining and other optimizations, use "<tt>linkonce_odr</tt>"
601 linkage.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]602
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]603 <dt><tt><b><a name="linkage_weak">weak</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]604 <dd>"<tt>weak</tt>" linkage has the same merging semantics as
605 <tt>linkonce</tt> linkage, except that unreferenced globals with
606 <tt>weak</tt> linkage may not be discarded. This is used for globals that
607 are declared "weak" in C source code.</dd>
608
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]609 <dt><tt><b><a name="linkage_common">common</a></b></tt></dt>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]610 <dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
611 they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
612 global scope.
613 Symbols with "<tt>common</tt>" linkage are merged in the same way as
614 <tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]615 <tt>common</tt> symbols may not have an explicit section,
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]616 must have a zero initializer, and may not be marked '<a
Chris Lattner0aff0b22009-08-05 05:41:44 +0000[diff] [blame]617 href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
618 have common linkage.</dd>
Chris Lattnerd0554882009-08-05 05:21:07 +0000[diff] [blame]619
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]620
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]621 <dt><tt><b><a name="linkage_appending">appending</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]622 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]623 pointer to array type. When two global variables with appending linkage
624 are linked together, the two global arrays are appended together. This is
625 the LLVM, typesafe, equivalent of having the system linker append together
626 "sections" with identical names when .o files are linked.</dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]627
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]628 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]629 <dd>The semantics of this linkage follow the ELF object file model: the symbol
630 is weak until linked, if not linked, the symbol becomes null instead of
631 being an undefined reference.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000[diff] [blame]632
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]633 <dt><tt><b><a name="linkage_linkonce_odr">linkonce_odr</a></b></tt></dt>
634 <dt><tt><b><a name="linkage_weak_odr">weak_odr</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]635 <dd>Some languages allow differing globals to be merged, such as two functions
636 with different semantics. Other languages, such as <tt>C++</tt>, ensure
Bill Wendling03bcd6e2010-07-01 21:55:59 +0000[diff] [blame]637 that only equivalent globals are ever merged (the "one definition rule"
638 &mdash; "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]639 and <tt>weak_odr</tt> linkage types to indicate that the global will only
640 be merged with equivalent globals. These linkage types are otherwise the
641 same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]642
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]643 <dt><tt><b><a name="linkage_external">external</a></b></tt></dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000[diff] [blame]644 <dd>If none of the above identifiers are used, the global is externally
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]645 visible, meaning that it participates in linkage and can be used to
646 resolve external symbol references.</dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000[diff] [blame]647</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]648
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]649<p>The next two types of linkage are targeted for Microsoft Windows platform
650 only. They are designed to support importing (exporting) symbols from (to)
651 DLLs (Dynamic Link Libraries).</p>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]652
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]653<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]654 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]655 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]656 or variable via a global pointer to a pointer that is set up by the DLL
657 exporting the symbol. On Microsoft Windows targets, the pointer name is
658 formed by combining <code>__imp_</code> and the function or variable
659 name.</dd>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]660
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]661 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt></dt>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000[diff] [blame]662 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]663 pointer to a pointer in a DLL, so that it can be referenced with the
664 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
665 name is formed by combining <code>__imp_</code> and the function or
666 variable name.</dd>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]667</dl>
668
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]669<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
670 another module defined a "<tt>.LC0</tt>" variable and was linked with this
671 one, one of the two would be renamed, preventing a collision. Since
672 "<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
673 declarations), they are accessible outside of the current module.</p>
674
675<p>It is illegal for a function <i>declaration</i> to have any linkage type
Bill Wendlingb4d076e2011-10-11 06:41:28 +0000[diff] [blame]676 other than <tt>external</tt>, <tt>dllimport</tt>
677 or <tt>extern_weak</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]678
Duncan Sands12da8ce2009-03-07 15:45:40 +0000[diff] [blame]679<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]680 or <tt>weak_odr</tt> linkages.</p>
681
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]682</div>
683
684<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]685<h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]686 <a name="callingconv">Calling Conventions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]687</h3>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]688
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]689<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]690
691<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]692 and <a href="#i_invoke">invokes</a> can all have an optional calling
693 convention specified for the call. The calling convention of any pair of
694 dynamic caller/callee must match, or the behavior of the program is
695 undefined. The following calling conventions are supported by LLVM, and more
696 may be added in the future:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]697
698<dl>
699 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]700 <dd>This calling convention (the default if no other calling convention is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]701 specified) matches the target C calling conventions. This calling
702 convention supports varargs function calls and tolerates some mismatch in
703 the declared prototype and implemented declaration of the function (as
704 does normal C).</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]705
706 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]707 <dd>This calling convention attempts to make calls as fast as possible
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]708 (e.g. by passing things in registers). This calling convention allows the
709 target to use whatever tricks it wants to produce fast code for the
710 target, without having to conform to an externally specified ABI
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]711 (Application Binary Interface).
712 <a href="CodeGenerator.html#tailcallopt">Tail calls can only be optimized
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]713 when this or the GHC convention is used.</a> This calling convention
714 does not support varargs and requires the prototype of all callees to
715 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]716
717 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]718 <dd>This calling convention attempts to make code in the caller as efficient
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]719 as possible under the assumption that the call is not commonly executed.
720 As such, these calls often preserve all registers so that the call does
721 not break any live ranges in the caller side. This calling convention
722 does not support varargs and requires the prototype of all callees to
723 exactly match the prototype of the function definition.</dd>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]724
Chris Lattnera179e4d2010-03-11 00:22:57 +0000[diff] [blame]725 <dt><b>"<tt>cc <em>10</em></tt>" - GHC convention</b>:</dt>
726 <dd>This calling convention has been implemented specifically for use by the
727 <a href="http://www.haskell.org/ghc">Glasgow Haskell Compiler (GHC)</a>.
728 It passes everything in registers, going to extremes to achieve this by
729 disabling callee save registers. This calling convention should not be
730 used lightly but only for specific situations such as an alternative to
731 the <em>register pinning</em> performance technique often used when
732 implementing functional programming languages.At the moment only X86
733 supports this convention and it has the following limitations:
734 <ul>
735 <li>On <em>X86-32</em> only supports up to 4 bit type parameters. No
736 floating point types are supported.</li>
737 <li>On <em>X86-64</em> only supports up to 10 bit type parameters and
738 6 floating point parameters.</li>
739 </ul>
740 This calling convention supports
741 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> but
742 requires both the caller and callee are using it.
743 </dd>
744
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]745 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]746 <dd>Any calling convention may be specified by number, allowing
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]747 target-specific calling conventions to be used. Target specific calling
748 conventions start at 64.</dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000[diff] [blame]749</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]750
751<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]752 support Pascal conventions or any other well-known target-independent
753 convention.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]754
755</div>
756
757<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]758<h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]759 <a name="visibility">Visibility Styles</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]760</h3>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]761
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]762<div>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]763
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]764<p>All Global Variables and Functions have one of the following visibility
765 styles:</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]766
767<dl>
768 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]769 <dd>On targets that use the ELF object file format, default visibility means
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]770 that the declaration is visible to other modules and, in shared libraries,
771 means that the declared entity may be overridden. On Darwin, default
772 visibility means that the declaration is visible to other modules. Default
773 visibility corresponds to "external linkage" in the language.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]774
775 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]776 <dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]777 object if they are in the same shared object. Usually, hidden visibility
778 indicates that the symbol will not be placed into the dynamic symbol
779 table, so no other module (executable or shared library) can reference it
780 directly.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]781
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]782 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000[diff] [blame]783 <dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]784 the dynamic symbol table, but that references within the defining module
785 will bind to the local symbol. That is, the symbol cannot be overridden by
786 another module.</dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]787</dl>
788
789</div>
790
791<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]792<h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]793 <a name="namedtypes">Named Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]794</h3>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]795
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]796<div>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]797
798<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]799 it easier to read the IR and make the IR more condensed (particularly when
800 recursive types are involved). An example of a name specification is:</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]801
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]802<pre class="doc_code">
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]803%mytype = type { %mytype*, i32 }
804</pre>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]805
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]806<p>You may give a name to any <a href="#typesystem">type</a> except
Chris Lattner249b9762010-08-17 23:26:04 +0000[diff] [blame]807 "<a href="#t_void">void</a>". Type name aliases may be used anywhere a type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]808 is expected with the syntax "%mytype".</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]809
810<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]811 and that you can therefore specify multiple names for the same type. This
812 often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
813 uses structural typing, the name is not part of the type. When printing out
814 LLVM IR, the printer will pick <em>one name</em> to render all types of a
815 particular shape. This means that if you have code where two different
816 source types end up having the same LLVM type, that the dumper will sometimes
817 print the "wrong" or unexpected type. This is an important design point and
818 isn't going to change.</p>
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]819
820</div>
821
Chris Lattnerbc088212009-01-11 20:53:49 +0000[diff] [blame]822<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]823<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]824 <a name="globalvars">Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]825</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]826
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]827<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]828
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]829<p>Global variables define regions of memory allocated at compilation time
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]830 instead of run-time. Global variables may optionally be initialized, may
831 have an explicit section to be placed in, and may have an optional explicit
832 alignment specified. A variable may be defined as "thread_local", which
833 means that it will not be shared by threads (each thread will have a
834 separated copy of the variable). A variable may be defined as a global
835 "constant," which indicates that the contents of the variable
836 will <b>never</b> be modified (enabling better optimization, allowing the
837 global data to be placed in the read-only section of an executable, etc).
838 Note that variables that need runtime initialization cannot be marked
839 "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000[diff] [blame]840
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]841<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
842 constant, even if the final definition of the global is not. This capability
843 can be used to enable slightly better optimization of the program, but
844 requires the language definition to guarantee that optimizations based on the
845 'constantness' are valid for the translation units that do not include the
846 definition.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]847
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]848<p>As SSA values, global variables define pointer values that are in scope
849 (i.e. they dominate) all basic blocks in the program. Global variables
850 always define a pointer to their "content" type because they describe a
851 region of memory, and all memory objects in LLVM are accessed through
852 pointers.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]853
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]854<p>Global variables can be marked with <tt>unnamed_addr</tt> which indicates
855 that the address is not significant, only the content. Constants marked
Rafael Espindolaf1ed7812011-01-15 08:20:57 +0000[diff] [blame]856 like this can be merged with other constants if they have the same
857 initializer. Note that a constant with significant address <em>can</em>
858 be merged with a <tt>unnamed_addr</tt> constant, the result being a
859 constant whose address is significant.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]860
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]861<p>A global variable may be declared to reside in a target-specific numbered
862 address space. For targets that support them, address spaces may affect how
863 optimizations are performed and/or what target instructions are used to
864 access the variable. The default address space is zero. The address space
865 qualifier must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000[diff] [blame]866
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]867<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]868 supports it, it will emit globals to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]869
Chris Lattner78e00bc2010-04-28 00:13:42 +0000[diff] [blame]870<p>An explicit alignment may be specified for a global, which must be a power
871 of 2. If not present, or if the alignment is set to zero, the alignment of
872 the global is set by the target to whatever it feels convenient. If an
873 explicit alignment is specified, the global is forced to have exactly that
Chris Lattner4bd85e42010-04-28 00:31:12 +0000[diff] [blame]874 alignment. Targets and optimizers are not allowed to over-align the global
875 if the global has an assigned section. In this case, the extra alignment
876 could be observable: for example, code could assume that the globals are
877 densely packed in their section and try to iterate over them as an array,
878 alignment padding would break this iteration.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]879
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]880<p>For example, the following defines a global in a numbered address space with
881 an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]882
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]883<pre class="doc_code">
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000[diff] [blame]884@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000[diff] [blame]885</pre>
886
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]887</div>
888
889
890<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]891<h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]892 <a name="functionstructure">Functions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]893</h3>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]894
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]895<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]896
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]897<p>LLVM function definitions consist of the "<tt>define</tt>" keyword, an
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]898 optional <a href="#linkage">linkage type</a>, an optional
899 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]900 <a href="#callingconv">calling convention</a>,
901 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]902 <a href="#paramattrs">parameter attribute</a> for the return type, a function
903 name, a (possibly empty) argument list (each with optional
904 <a href="#paramattrs">parameter attributes</a>), optional
905 <a href="#fnattrs">function attributes</a>, an optional section, an optional
906 alignment, an optional <a href="#gc">garbage collector name</a>, an opening
907 curly brace, a list of basic blocks, and a closing curly brace.</p>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000[diff] [blame]908
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]909<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
910 optional <a href="#linkage">linkage type</a>, an optional
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]911 <a href="#visibility">visibility style</a>, an optional
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]912 <a href="#callingconv">calling convention</a>,
913 an optional <tt>unnamed_addr</tt> attribute, a return type, an optional
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]914 <a href="#paramattrs">parameter attribute</a> for the return type, a function
915 name, a possibly empty list of arguments, an optional alignment, and an
916 optional <a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]917
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]918<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]919 (Control Flow Graph) for the function. Each basic block may optionally start
920 with a label (giving the basic block a symbol table entry), contains a list
921 of instructions, and ends with a <a href="#terminators">terminator</a>
922 instruction (such as a branch or function return).</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]923
Chris Lattnera59fb102007-06-08 16:52:14 +0000[diff] [blame]924<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]925 executed on entrance to the function, and it is not allowed to have
926 predecessor basic blocks (i.e. there can not be any branches to the entry
927 block of a function). Because the block can have no predecessors, it also
928 cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]929
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]930<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]931 supports it, it will emit functions to the section specified.</p>
Chris Lattner662c8722005-11-12 00:45:07 +0000[diff] [blame]932
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]933<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]934 the alignment is set to zero, the alignment of the function is set by the
935 target to whatever it feels convenient. If an explicit alignment is
936 specified, the function is forced to have at least that much alignment. All
937 alignments must be a power of 2.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]938
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]939<p>If the <tt>unnamed_addr</tt> attribute is given, the address is know to not
Bill Wendlingef3cdea2011-11-04 20:40:41 +0000[diff] [blame]940 be significant and two identical functions can be merged.</p>
Rafael Espindola45e6c192011-01-08 16:42:36 +0000[diff] [blame]941
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]942<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]943<pre class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000[diff] [blame]944define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]945 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
946 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
947 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
948 [<a href="#gc">gc</a>] { ... }
949</pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]950
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]951</div>
952
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]953<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]954<h3>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]955 <a name="aliasstructure">Aliases</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]956</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]957
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]958<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]959
960<p>Aliases act as "second name" for the aliasee value (which can be either
961 function, global variable, another alias or bitcast of global value). Aliases
962 may have an optional <a href="#linkage">linkage type</a>, and an
963 optional <a href="#visibility">visibility style</a>.</p>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]964
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]965<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]966<pre class="doc_code">
Duncan Sands7e99a942008-09-12 20:48:21 +0000[diff] [blame]967@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]968</pre>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000[diff] [blame]969
970</div>
971
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]972<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]973<h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]974 <a name="namedmetadatastructure">Named Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]975</h3>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]976
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]977<div>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]978
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]979<p>Named metadata is a collection of metadata. <a href="#metadata">Metadata
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]980 nodes</a> (but not metadata strings) are the only valid operands for
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]981 a named metadata.</p>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]982
983<h5>Syntax:</h5>
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]984<pre class="doc_code">
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]985; Some unnamed metadata nodes, which are referenced by the named metadata.
986!0 = metadata !{metadata !"zero"}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]987!1 = metadata !{metadata !"one"}
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]988!2 = metadata !{metadata !"two"}
Dan Gohman58cd65f2010-07-13 19:48:13 +0000[diff] [blame]989; A named metadata.
Dan Gohman093cb792010-07-21 18:54:18 +0000[diff] [blame]990!name = !{!0, !1, !2}
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]991</pre>
Devang Pateld1a89692010-01-11 19:35:55 +0000[diff] [blame]992
993</div>
994
995<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]996<h3>
997 <a name="paramattrs">Parameter Attributes</a>
998</h3>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]999
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1000<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1001
1002<p>The return type and each parameter of a function type may have a set of
1003 <i>parameter attributes</i> associated with them. Parameter attributes are
1004 used to communicate additional information about the result or parameters of
1005 a function. Parameter attributes are considered to be part of the function,
1006 not of the function type, so functions with different parameter attributes
1007 can have the same function type.</p>
1008
1009<p>Parameter attributes are simple keywords that follow the type specified. If
1010 multiple parameter attributes are needed, they are space separated. For
1011 example:</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1012
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1013<pre class="doc_code">
Nick Lewyckydac78d82009-02-15 23:06:14 +0000[diff] [blame]1014declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000[diff] [blame]1015declare i32 @atoi(i8 zeroext)
1016declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1017</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1018
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1019<p>Note that any attributes for the function result (<tt>nounwind</tt>,
1020 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1021
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1022<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1023
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1024<dl>
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1025 <dt><tt><b>zeroext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1026 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarichac106272011-03-16 22:20:18 +0000[diff] [blame]1027 should be zero-extended to the extent required by the target's ABI (which
1028 is usually 32-bits, but is 8-bits for a i1 on x86-64) by the caller (for a
1029 parameter) or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1030
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1031 <dt><tt><b>signext</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1032 <dd>This indicates to the code generator that the parameter or return value
Cameron Zwarich341c36d2011-03-17 14:21:58 +0000[diff] [blame]1033 should be sign-extended to the extent required by the target's ABI (which
1034 is usually 32-bits) by the caller (for a parameter) or the callee (for a
1035 return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1036
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1037 <dt><tt><b>inreg</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1038 <dd>This indicates that this parameter or return value should be treated in a
1039 special target-dependent fashion during while emitting code for a function
1040 call or return (usually, by putting it in a register as opposed to memory,
1041 though some targets use it to distinguish between two different kinds of
1042 registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000[diff] [blame]1043
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1044 <dt><tt><b><a name="byval">byval</a></b></tt></dt>
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1045 <dd><p>This indicates that the pointer parameter should really be passed by
1046 value to the function. The attribute implies that a hidden copy of the
1047 pointee
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1048 is made between the caller and the callee, so the callee is unable to
1049 modify the value in the callee. This attribute is only valid on LLVM
1050 pointer arguments. It is generally used to pass structs and arrays by
1051 value, but is also valid on pointers to scalars. The copy is considered
1052 to belong to the caller not the callee (for example,
1053 <tt><a href="#readonly">readonly</a></tt> functions should not write to
1054 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattnerd78dbee2010-11-20 23:49:06 +0000[diff] [blame]1055 values.</p>
1056
1057 <p>The byval attribute also supports specifying an alignment with
1058 the align attribute. It indicates the alignment of the stack slot to
1059 form and the known alignment of the pointer specified to the call site. If
1060 the alignment is not specified, then the code generator makes a
1061 target-specific assumption.</p></dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1062
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1063 <dt><tt><b><a name="sret">sret</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1064 <dd>This indicates that the pointer parameter specifies the address of a
1065 structure that is the return value of the function in the source program.
1066 This pointer must be guaranteed by the caller to be valid: loads and
1067 stores to the structure may be assumed by the callee to not to trap. This
1068 may only be applied to the first parameter. This is not a valid attribute
1069 for return values. </dd>
1070
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1071 <dt><tt><b><a name="noalias">noalias</a></b></tt></dt>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1072 <dd>This indicates that pointer values
1073 <a href="#pointeraliasing"><i>based</i></a> on the argument or return
Dan Gohmande256292010-07-02 23:46:54 +0000[diff] [blame]1074 value do not alias pointer values which are not <i>based</i> on it,
1075 ignoring certain "irrelevant" dependencies.
1076 For a call to the parent function, dependencies between memory
1077 references from before or after the call and from those during the call
1078 are "irrelevant" to the <tt>noalias</tt> keyword for the arguments and
1079 return value used in that call.
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1080 The caller shares the responsibility with the callee for ensuring that
1081 these requirements are met.
1082 For further details, please see the discussion of the NoAlias response in
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1083 <a href="AliasAnalysis.html#MustMayNo">alias analysis</a>.<br>
1084<br>
John McCall72ed8902010-07-06 21:07:14 +0000[diff] [blame]1085 Note that this definition of <tt>noalias</tt> is intentionally
1086 similar to the definition of <tt>restrict</tt> in C99 for function
Chris Lattner5eff9ca2010-07-06 20:51:35 +0000[diff] [blame]1087 arguments, though it is slightly weaker.
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]1088<br>
1089 For function return values, C99's <tt>restrict</tt> is not meaningful,
1090 while LLVM's <tt>noalias</tt> is.
1091 </dd>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1092
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1093 <dt><tt><b><a name="nocapture">nocapture</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1094 <dd>This indicates that the callee does not make any copies of the pointer
1095 that outlive the callee itself. This is not a valid attribute for return
1096 values.</dd>
1097
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]1098 <dt><tt><b><a name="nest">nest</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1099 <dd>This indicates that the pointer parameter can be excised using the
1100 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
1101 attribute for return values.</dd>
1102</dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1103
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1104</div>
1105
1106<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1107<h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1108 <a name="gc">Garbage Collector Names</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1109</h3>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1110
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1111<div>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1112
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1113<p>Each function may specify a garbage collector name, which is simply a
1114 string:</p>
1115
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1116<pre class="doc_code">
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1117define void @f() gc "name" { ... }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1118</pre>
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1119
1120<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1121 collector which will cause the compiler to alter its output in order to
1122 support the named garbage collection algorithm.</p>
1123
Gordon Henriksen71183b62007-12-10 03:18:06 +0000[diff] [blame]1124</div>
1125
1126<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1127<h3>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1128 <a name="fnattrs">Function Attributes</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1129</h3>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1130
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1131<div>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1132
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1133<p>Function attributes are set to communicate additional information about a
1134 function. Function attributes are considered to be part of the function, not
1135 of the function type, so functions with different parameter attributes can
1136 have the same function type.</p>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1137
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1138<p>Function attributes are simple keywords that follow the type specified. If
1139 multiple attributes are needed, they are space separated. For example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1140
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1141<pre class="doc_code">
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1142define void @f() noinline { ... }
1143define void @f() alwaysinline { ... }
1144define void @f() alwaysinline optsize { ... }
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1145define void @f() optsize { ... }
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1146</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1147
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1148<dl>
Kostya Serebryanya5054ad2012-01-20 17:56:17 +0000[diff] [blame]1149 <dt><tt><b>address_safety</b></tt></dt>
1150 <dd>This attribute indicates that the address safety analysis
1151 is enabled for this function. </dd>
1152
Charles Davisbe5557e2010-02-12 00:31:15 +0000[diff] [blame]1153 <dt><tt><b>alignstack(&lt;<em>n</em>&gt;)</b></tt></dt>
1154 <dd>This attribute indicates that, when emitting the prologue and epilogue,
1155 the backend should forcibly align the stack pointer. Specify the
1156 desired alignment, which must be a power of two, in parentheses.
1157
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1158 <dt><tt><b>alwaysinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1159 <dd>This attribute indicates that the inliner should attempt to inline this
1160 function into callers whenever possible, ignoring any active inlining size
1161 threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1162
Dan Gohman8bd11f12011-06-16 16:03:13 +0000[diff] [blame]1163 <dt><tt><b>nonlazybind</b></tt></dt>
1164 <dd>This attribute suppresses lazy symbol binding for the function. This
1165 may make calls to the function faster, at the cost of extra program
1166 startup time if the function is not called during program startup.</dd>
1167
Jakob Stoklund Olesen74bb06c2010-02-06 01:16:28 +0000[diff] [blame]1168 <dt><tt><b>inlinehint</b></tt></dt>
1169 <dd>This attribute indicates that the source code contained a hint that inlining
1170 this function is desirable (such as the "inline" keyword in C/C++). It
1171 is just a hint; it imposes no requirements on the inliner.</dd>
1172
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1173 <dt><tt><b>naked</b></tt></dt>
1174 <dd>This attribute disables prologue / epilogue emission for the function.
1175 This can have very system-specific consequences.</dd>
1176
1177 <dt><tt><b>noimplicitfloat</b></tt></dt>
1178 <dd>This attributes disables implicit floating point instructions.</dd>
1179
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1180 <dt><tt><b>noinline</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1181 <dd>This attribute indicates that the inliner should never inline this
1182 function in any situation. This attribute may not be used together with
1183 the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1184
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1185 <dt><tt><b>noredzone</b></tt></dt>
1186 <dd>This attribute indicates that the code generator should not use a red
1187 zone, even if the target-specific ABI normally permits it.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +0000[diff] [blame]1188
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1189 <dt><tt><b>noreturn</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1190 <dd>This function attribute indicates that the function never returns
1191 normally. This produces undefined behavior at runtime if the function
1192 ever does dynamically return.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +0000[diff] [blame]1193
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1194 <dt><tt><b>nounwind</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1195 <dd>This function attribute indicates that the function never returns with an
1196 unwind or exceptional control flow. If the function does unwind, its
1197 runtime behavior is undefined.</dd>
Bill Wendling0f5541e2008-11-26 19:07:40 +0000[diff] [blame]1198
Nick Lewycky14b58da2010-07-06 18:24:09 +0000[diff] [blame]1199 <dt><tt><b>optsize</b></tt></dt>
1200 <dd>This attribute suggests that optimization passes and code generator passes
1201 make choices that keep the code size of this function low, and otherwise
1202 do optimizations specifically to reduce code size.</dd>
1203
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1204 <dt><tt><b>readnone</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1205 <dd>This attribute indicates that the function computes its result (or decides
1206 to unwind an exception) based strictly on its arguments, without
1207 dereferencing any pointer arguments or otherwise accessing any mutable
1208 state (e.g. memory, control registers, etc) visible to caller functions.
1209 It does not write through any pointer arguments
1210 (including <tt><a href="#byval">byval</a></tt> arguments) and never
1211 changes any state visible to callers. This means that it cannot unwind
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1212 exceptions by calling the <tt>C++</tt> exception throwing methods.</dd>
Devang Patel310fd4a2009-06-12 19:45:19 +0000[diff] [blame]1213
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1214 <dt><tt><b><a name="readonly">readonly</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1215 <dd>This attribute indicates that the function does not write through any
1216 pointer arguments (including <tt><a href="#byval">byval</a></tt>
1217 arguments) or otherwise modify any state (e.g. memory, control registers,
1218 etc) visible to caller functions. It may dereference pointer arguments
1219 and read state that may be set in the caller. A readonly function always
1220 returns the same value (or unwinds an exception identically) when called
1221 with the same set of arguments and global state. It cannot unwind an
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]1222 exception by calling the <tt>C++</tt> exception throwing methods.</dd>
Anton Korobeynikovc8ce7b082009-07-17 18:07:26 +0000[diff] [blame]1223
Bill Wendlingb437ab82011-12-05 21:27:54 +0000[diff] [blame]1224 <dt><tt><b><a name="returns_twice">returns_twice</a></b></tt></dt>
1225 <dd>This attribute indicates that this function can return twice. The
1226 C <code>setjmp</code> is an example of such a function. The compiler
1227 disables some optimizations (like tail calls) in the caller of these
1228 functions.</dd>
1229
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1230 <dt><tt><b><a name="ssp">ssp</a></b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1231 <dd>This attribute indicates that the function should emit a stack smashing
1232 protector. It is in the form of a "canary"&mdash;a random value placed on
1233 the stack before the local variables that's checked upon return from the
1234 function to see if it has been overwritten. A heuristic is used to
1235 determine if a function needs stack protectors or not.<br>
1236<br>
1237 If a function that has an <tt>ssp</tt> attribute is inlined into a
1238 function that doesn't have an <tt>ssp</tt> attribute, then the resulting
1239 function will have an <tt>ssp</tt> attribute.</dd>
1240
Bill Wendling7f4a3362009-11-02 00:24:16 +0000[diff] [blame]1241 <dt><tt><b>sspreq</b></tt></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1242 <dd>This attribute indicates that the function should <em>always</em> emit a
1243 stack smashing protector. This overrides
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1244 the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
1245<br>
1246 If a function that has an <tt>sspreq</tt> attribute is inlined into a
1247 function that doesn't have an <tt>sspreq</tt> attribute or which has
1248 an <tt>ssp</tt> attribute, then the resulting function will have
1249 an <tt>sspreq</tt> attribute.</dd>
Rafael Espindola163d6752011-07-25 15:27:59 +0000[diff] [blame]1250
1251 <dt><tt><b><a name="uwtable">uwtable</a></b></tt></dt>
1252 <dd>This attribute indicates that the ABI being targeted requires that
1253 an unwind table entry be produce for this function even if we can
1254 show that no exceptions passes by it. This is normally the case for
1255 the ELF x86-64 abi, but it can be disabled for some compilation
1256 units.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +0000[diff] [blame]1257</dl>
1258
Devang Patelcaacdba2008-09-04 23:05:13 +0000[diff] [blame]1259</div>
1260
1261<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1262<h3>
Chris Lattner93564892006-04-08 04:40:53 +0000[diff] [blame]1263 <a name="moduleasm">Module-Level Inline Assembly</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1264</h3>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1265
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1266<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1267
1268<p>Modules may contain "module-level inline asm" blocks, which corresponds to
1269 the GCC "file scope inline asm" blocks. These blocks are internally
1270 concatenated by LLVM and treated as a single unit, but may be separated in
1271 the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1272
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1273<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]1274module asm "inline asm code goes here"
1275module asm "more can go here"
1276</pre>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1277
1278<p>The strings can contain any character by escaping non-printable characters.
1279 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1280 for the number.</p>
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1281
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1282<p>The inline asm code is simply printed to the machine code .s file when
1283 assembly code is generated.</p>
1284
Chris Lattner91c15c42006-01-23 23:23:47 +0000[diff] [blame]1285</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1286
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1287<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1288<h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1289 <a name="datalayout">Data Layout</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1290</h3>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1291
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1292<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1293
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1294<p>A module may specify a target specific data layout string that specifies how
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1295 data is to be laid out in memory. The syntax for the data layout is
1296 simply:</p>
1297
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]1298<pre class="doc_code">
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1299target datalayout = "<i>layout specification</i>"
1300</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1301
1302<p>The <i>layout specification</i> consists of a list of specifications
1303 separated by the minus sign character ('-'). Each specification starts with
1304 a letter and may include other information after the letter to define some
1305 aspect of the data layout. The specifications accepted are as follows:</p>
1306
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1307<dl>
1308 <dt><tt>E</tt></dt>
1309 <dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1310 bits with the most significance have the lowest address location.</dd>
1311
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1312 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1313 <dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1314 the bits with the least significance have the lowest address
1315 location.</dd>
1316
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1317 <dt><tt>S<i>size</i></tt></dt>
1318 <dd>Specifies the natural alignment of the stack in bits. Alignment promotion
1319 of stack variables is limited to the natural stack alignment to avoid
1320 dynamic stack realignment. The stack alignment must be a multiple of
Lang Hamesff2c52c2011-10-11 17:50:14 +0000[diff] [blame]1321 8-bits. If omitted, the natural stack alignment defaults to "unspecified",
1322 which does not prevent any alignment promotions.</dd>
Lang Hamesde7ab802011-10-10 23:42:08 +0000[diff] [blame]1323
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1324 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1325 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1326 <i>preferred</i> alignments. All sizes are in bits. Specifying
1327 the <i>pref</i> alignment is optional. If omitted, the
1328 preceding <tt>:</tt> should be omitted too.</dd>
1329
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1330 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1331 <dd>This specifies the alignment for an integer type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1332 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1333
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1334 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1335 <dd>This specifies the alignment for a vector type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1336 <i>size</i>.</dd>
1337
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1338 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1339 <dd>This specifies the alignment for a floating point type of a given bit
Dale Johannesence522852010-05-28 18:54:47 +0000[diff] [blame]1340 <i>size</i>. Only values of <i>size</i> that are supported by the target
1341 will work. 32 (float) and 64 (double) are supported on all targets;
1342 80 or 128 (different flavors of long double) are also supported on some
1343 targets.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1344
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1345 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1346 <dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1347 <i>size</i>.</dd>
1348
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1349 <dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1350 <dd>This specifies the alignment for a stack object of a given bit
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1351 <i>size</i>.</dd>
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1352
1353 <dt><tt>n<i>size1</i>:<i>size2</i>:<i>size3</i>...</tt></dt>
1354 <dd>This specifies a set of native integer widths for the target CPU
1355 in bits. For example, it might contain "n32" for 32-bit PowerPC,
1356 "n32:64" for PowerPC 64, or "n8:16:32:64" for X86-64. Elements of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]1357 this set are considered to support most general arithmetic
Chris Lattnera381eff2009-11-07 09:35:34 +0000[diff] [blame]1358 operations efficiently.</dd>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1359</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1360
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1361<p>When constructing the data layout for a given target, LLVM starts with a
Dan Gohman61110ae2010-04-28 00:36:01 +0000[diff] [blame]1362 default set of specifications which are then (possibly) overridden by the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1363 specifications in the <tt>datalayout</tt> keyword. The default specifications
1364 are given in this list:</p>
1365
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1366<ul>
1367 <li><tt>E</tt> - big endian</li>
Dan Gohman8ad777d2010-02-23 02:44:03 +0000[diff] [blame]1368 <li><tt>p:64:64:64</tt> - 64-bit pointers with 64-bit alignment</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1369 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1370 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1371 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1372 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]1373 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1374 alignment of 64-bits</li>
1375 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1376 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1377 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1378 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1379 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar7921a592009-06-08 22:17:53 +0000[diff] [blame]1380 <li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1381</ul>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1382
1383<p>When LLVM is determining the alignment for a given type, it uses the
1384 following rules:</p>
1385
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1386<ol>
1387 <li>If the type sought is an exact match for one of the specifications, that
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1388 specification is used.</li>
1389
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1390 <li>If no match is found, and the type sought is an integer type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1391 smallest integer type that is larger than the bitwidth of the sought type
1392 is used. If none of the specifications are larger than the bitwidth then
1393 the the largest integer type is used. For example, given the default
1394 specifications above, the i7 type will use the alignment of i8 (next
1395 largest) while both i65 and i256 will use the alignment of i64 (largest
1396 specified).</li>
1397
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1398 <li>If no match is found, and the type sought is a vector type, then the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1399 largest vector type that is smaller than the sought vector type will be
1400 used as a fall back. This happens because &lt;128 x double&gt; can be
1401 implemented in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1402</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1403
Chris Lattner48797402011-10-11 23:01:39 +0000[diff] [blame]1404<p>The function of the data layout string may not be what you expect. Notably,
1405 this is not a specification from the frontend of what alignment the code
1406 generator should use.</p>
1407
1408<p>Instead, if specified, the target data layout is required to match what the
1409 ultimate <em>code generator</em> expects. This string is used by the
1410 mid-level optimizers to
1411 improve code, and this only works if it matches what the ultimate code
1412 generator uses. If you would like to generate IR that does not embed this
1413 target-specific detail into the IR, then you don't have to specify the
1414 string. This will disable some optimizations that require precise layout
1415 information, but this also prevents those optimizations from introducing
1416 target specificity into the IR.</p>
1417
1418
1419
Reid Spencer50c723a2007-02-19 23:54:10 +0000[diff] [blame]1420</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1421
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1422<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1423<h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1424 <a name="pointeraliasing">Pointer Aliasing Rules</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1425</h3>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1426
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1427<div>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1428
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1429<p>Any memory access must be done through a pointer value associated
Andreas Bolkae39f0332009-07-27 20:37:10 +0000[diff] [blame]1430with an address range of the memory access, otherwise the behavior
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1431is undefined. Pointer values are associated with address ranges
1432according to the following rules:</p>
1433
1434<ul>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1435 <li>A pointer value is associated with the addresses associated with
1436 any value it is <i>based</i> on.
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1437 <li>An address of a global variable is associated with the address
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1438 range of the variable's storage.</li>
1439 <li>The result value of an allocation instruction is associated with
1440 the address range of the allocated storage.</li>
1441 <li>A null pointer in the default address-space is associated with
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1442 no address.</li>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1443 <li>An integer constant other than zero or a pointer value returned
1444 from a function not defined within LLVM may be associated with address
1445 ranges allocated through mechanisms other than those provided by
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1446 LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1447 allocated by mechanisms provided by LLVM.</li>
Dan Gohmandf12d082010-07-02 18:41:32 +0000[diff] [blame]1448</ul>
1449
1450<p>A pointer value is <i>based</i> on another pointer value according
1451 to the following rules:</p>
1452
1453<ul>
1454 <li>A pointer value formed from a
1455 <tt><a href="#i_getelementptr">getelementptr</a></tt> operation
1456 is <i>based</i> on the first operand of the <tt>getelementptr</tt>.</li>
1457 <li>The result value of a
1458 <tt><a href="#i_bitcast">bitcast</a></tt> is <i>based</i> on the operand
1459 of the <tt>bitcast</tt>.</li>
1460 <li>A pointer value formed by an
1461 <tt><a href="#i_inttoptr">inttoptr</a></tt> is <i>based</i> on all
1462 pointer values that contribute (directly or indirectly) to the
1463 computation of the pointer's value.</li>
1464 <li>The "<i>based</i> on" relationship is transitive.</li>
1465</ul>
1466
1467<p>Note that this definition of <i>"based"</i> is intentionally
1468 similar to the definition of <i>"based"</i> in C99, though it is
1469 slightly weaker.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1470
1471<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1472<tt><a href="#i_load">load</a></tt> merely indicates the size and
1473alignment of the memory from which to load, as well as the
Dan Gohman4eb47192010-06-17 19:23:50 +0000[diff] [blame]1474interpretation of the value. The first operand type of a
Andreas Bolka8ae4e242009-07-29 00:02:05 +0000[diff] [blame]1475<tt><a href="#i_store">store</a></tt> similarly only indicates the size
1476and alignment of the store.</p>
Dan Gohman6154a012009-07-27 18:07:55 +0000[diff] [blame]1477
1478<p>Consequently, type-based alias analysis, aka TBAA, aka
1479<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
1480LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
1481additional information which specialized optimization passes may use
1482to implement type-based alias analysis.</p>
1483
1484</div>
1485
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1486<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1487<h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1488 <a name="volatile">Volatile Memory Accesses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1489</h3>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1490
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1491<div>
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]1492
1493<p>Certain memory accesses, such as <a href="#i_load"><tt>load</tt></a>s, <a
1494href="#i_store"><tt>store</tt></a>s, and <a
1495href="#int_memcpy"><tt>llvm.memcpy</tt></a>s may be marked <tt>volatile</tt>.
1496The optimizers must not change the number of volatile operations or change their
1497order of execution relative to other volatile operations. The optimizers
1498<i>may</i> change the order of volatile operations relative to non-volatile
1499operations. This is not Java's "volatile" and has no cross-thread
1500synchronization behavior.</p>
1501
1502</div>
1503
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1504<!-- ======================================================================= -->
1505<h3>
1506 <a name="memmodel">Memory Model for Concurrent Operations</a>
1507</h3>
1508
1509<div>
1510
1511<p>The LLVM IR does not define any way to start parallel threads of execution
1512or to register signal handlers. Nonetheless, there are platform-specific
1513ways to create them, and we define LLVM IR's behavior in their presence. This
1514model is inspired by the C++0x memory model.</p>
1515
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1516<p>For a more informal introduction to this model, see the
1517<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.
1518
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1519<p>We define a <i>happens-before</i> partial order as the least partial order
1520that</p>
1521<ul>
1522 <li>Is a superset of single-thread program order, and</li>
1523 <li>When a <i>synchronizes-with</i> <tt>b</tt>, includes an edge from
1524 <tt>a</tt> to <tt>b</tt>. <i>Synchronizes-with</i> pairs are introduced
1525 by platform-specific techniques, like pthread locks, thread
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1526 creation, thread joining, etc., and by atomic instructions.
1527 (See also <a href="#ordering">Atomic Memory Ordering Constraints</a>).
1528 </li>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1529</ul>
1530
1531<p>Note that program order does not introduce <i>happens-before</i> edges
1532between a thread and signals executing inside that thread.</p>
1533
1534<p>Every (defined) read operation (load instructions, memcpy, atomic
1535loads/read-modify-writes, etc.) <var>R</var> reads a series of bytes written by
1536(defined) write operations (store instructions, atomic
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1537stores/read-modify-writes, memcpy, etc.). For the purposes of this section,
1538initialized globals are considered to have a write of the initializer which is
1539atomic and happens before any other read or write of the memory in question.
1540For each byte of a read <var>R</var>, <var>R<sub>byte</sub></var> may see
1541any write to the same byte, except:</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1542
1543<ul>
1544 <li>If <var>write<sub>1</sub></var> happens before
1545 <var>write<sub>2</sub></var>, and <var>write<sub>2</sub></var> happens
1546 before <var>R<sub>byte</sub></var>, then <var>R<sub>byte</sub></var>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1547 does not see <var>write<sub>1</sub></var>.
Bill Wendling537603b2011-07-31 06:45:03 +0000[diff] [blame]1548 <li>If <var>R<sub>byte</sub></var> happens before
1549 <var>write<sub>3</sub></var>, then <var>R<sub>byte</sub></var> does not
1550 see <var>write<sub>3</sub></var>.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1551</ul>
1552
1553<p>Given that definition, <var>R<sub>byte</sub></var> is defined as follows:
1554<ul>
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1555 <li>If <var>R</var> is volatile, the result is target-dependent. (Volatile
1556 is supposed to give guarantees which can support
1557 <code>sig_atomic_t</code> in C/C++, and may be used for accesses to
1558 addresses which do not behave like normal memory. It does not generally
1559 provide cross-thread synchronization.)
1560 <li>Otherwise, if there is no write to the same byte that happens before
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1561 <var>R<sub>byte</sub></var>, <var>R<sub>byte</sub></var> returns
1562 <tt>undef</tt> for that byte.
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1563 <li>Otherwise, if <var>R<sub>byte</sub></var> may see exactly one write,
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1564 <var>R<sub>byte</sub></var> returns the value written by that
1565 write.</li>
Eli Friedmanf12e4e92011-07-22 03:04:45 +0000[diff] [blame]1566 <li>Otherwise, if <var>R</var> is atomic, and all the writes
1567 <var>R<sub>byte</sub></var> may see are atomic, it chooses one of the
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1568 values written. See the <a href="#ordering">Atomic Memory Ordering
1569 Constraints</a> section for additional constraints on how the choice
1570 is made.
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1571 <li>Otherwise <var>R<sub>byte</sub></var> returns <tt>undef</tt>.</li>
1572</ul>
1573
1574<p><var>R</var> returns the value composed of the series of bytes it read.
1575This implies that some bytes within the value may be <tt>undef</tt>
1576<b>without</b> the entire value being <tt>undef</tt>. Note that this only
1577defines the semantics of the operation; it doesn't mean that targets will
1578emit more than one instruction to read the series of bytes.</p>
1579
1580<p>Note that in cases where none of the atomic intrinsics are used, this model
1581places only one restriction on IR transformations on top of what is required
1582for single-threaded execution: introducing a store to a byte which might not
Eli Friedman4bc9f3c2011-08-02 01:15:34 +0000[diff] [blame]1583otherwise be stored is not allowed in general. (Specifically, in the case
1584where another thread might write to and read from an address, introducing a
1585store can change a load that may see exactly one write into a load that may
1586see multiple writes.)</p>
Eli Friedman35b54aa2011-07-20 21:35:53 +0000[diff] [blame]1587
1588<!-- FIXME: This model assumes all targets where concurrency is relevant have
1589a byte-size store which doesn't affect adjacent bytes. As far as I can tell,
1590none of the backends currently in the tree fall into this category; however,
1591there might be targets which care. If there are, we want a paragraph
1592like the following:
1593
1594Targets may specify that stores narrower than a certain width are not
1595available; on such a target, for the purposes of this model, treat any
1596non-atomic write with an alignment or width less than the minimum width
1597as if it writes to the relevant surrounding bytes.
1598-->
1599
1600</div>
1601
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1602<!-- ======================================================================= -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1603<h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1604 <a name="ordering">Atomic Memory Ordering Constraints</a>
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1605</h3>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1606
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]1607<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1608
1609<p>Atomic instructions (<a href="#i_cmpxchg"><code>cmpxchg</code></a>,
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]1610<a href="#i_atomicrmw"><code>atomicrmw</code></a>,
1611<a href="#i_fence"><code>fence</code></a>,
1612<a href="#i_load"><code>atomic load</code></a>, and
Eli Friedman75362532011-08-09 23:26:12 +0000[diff] [blame]1613<a href="#i_store"><code>atomic store</code></a>) take an ordering parameter
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1614that determines which other atomic instructions on the same address they
1615<i>synchronize with</i>. These semantics are borrowed from Java and C++0x,
1616but are somewhat more colloquial. If these descriptions aren't precise enough,
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1617check those specs (see spec references in the
Nick Lewycky75499f52012-01-23 08:47:21 +0000[diff] [blame]1618<a href="Atomics.html#introduction">atomics guide</a>).
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1619<a href="#i_fence"><code>fence</code></a> instructions
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1620treat these orderings somewhat differently since they don't take an address.
1621See that instruction's documentation for details.</p>
1622
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1623<p>For a simpler introduction to the ordering constraints, see the
1624<a href="Atomics.html">LLVM Atomic Instructions and Concurrency Guide</a>.</p>
1625
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1626<dl>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1627<dt><code>unordered</code></dt>
1628<dd>The set of values that can be read is governed by the happens-before
1629partial order. A value cannot be read unless some operation wrote it.
1630This is intended to provide a guarantee strong enough to model Java's
1631non-volatile shared variables. This ordering cannot be specified for
1632read-modify-write operations; it is not strong enough to make them atomic
1633in any interesting way.</dd>
1634<dt><code>monotonic</code></dt>
1635<dd>In addition to the guarantees of <code>unordered</code>, there is a single
1636total order for modifications by <code>monotonic</code> operations on each
1637address. All modification orders must be compatible with the happens-before
1638order. There is no guarantee that the modification orders can be combined to
1639a global total order for the whole program (and this often will not be
1640possible). The read in an atomic read-modify-write operation
1641(<a href="#i_cmpxchg"><code>cmpxchg</code></a> and
1642<a href="#i_atomicrmw"><code>atomicrmw</code></a>)
1643reads the value in the modification order immediately before the value it
1644writes. If one atomic read happens before another atomic read of the same
1645address, the later read must see the same value or a later value in the
1646address's modification order. This disallows reordering of
1647<code>monotonic</code> (or stronger) operations on the same address. If an
1648address is written <code>monotonic</code>ally by one thread, and other threads
1649<code>monotonic</code>ally read that address repeatedly, the other threads must
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1650eventually see the write. This corresponds to the C++0x/C1x
1651<code>memory_order_relaxed</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1652<dt><code>acquire</code></dt>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1653<dd>In addition to the guarantees of <code>monotonic</code>,
Eli Friedman0cb3b562011-08-24 20:28:39 +0000[diff] [blame]1654a <i>synchronizes-with</i> edge may be formed with a <code>release</code>
1655operation. This is intended to model C++'s <code>memory_order_acquire</code>.</dd>
1656<dt><code>release</code></dt>
1657<dd>In addition to the guarantees of <code>monotonic</code>, if this operation
1658writes a value which is subsequently read by an <code>acquire</code> operation,
1659it <i>synchronizes-with</i> that operation. (This isn't a complete
1660description; see the C++0x definition of a release sequence.) This corresponds
1661to the C++0x/C1x <code>memory_order_release</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1662<dt><code>acq_rel</code> (acquire+release)</dt><dd>Acts as both an
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1663<code>acquire</code> and <code>release</code> operation on its address.
1664This corresponds to the C++0x/C1x <code>memory_order_acq_rel</code>.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1665<dt><code>seq_cst</code> (sequentially consistent)</dt><dd>
1666<dd>In addition to the guarantees of <code>acq_rel</code>
1667(<code>acquire</code> for an operation which only reads, <code>release</code>
1668for an operation which only writes), there is a global total order on all
1669sequentially-consistent operations on all addresses, which is consistent with
1670the <i>happens-before</i> partial order and with the modification orders of
1671all the affected addresses. Each sequentially-consistent read sees the last
Eli Friedman95f69a42011-08-22 21:35:27 +0000[diff] [blame]1672preceding write to the same address in this global order. This corresponds
1673to the C++0x/C1x <code>memory_order_seq_cst</code> and Java volatile.</dd>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]1674</dl>
1675
1676<p id="singlethread">If an atomic operation is marked <code>singlethread</code>,
1677it only <i>synchronizes with</i> or participates in modification and seq_cst
1678total orderings with other operations running in the same thread (for example,
1679in signal handlers).</p>
1680
1681</div>
1682
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1683</div>
1684
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1685<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1686<h2><a name="typesystem">Type System</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1687<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1688
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1689<div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1690
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1691<p>The LLVM type system is one of the most important features of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1692 intermediate representation. Being typed enables a number of optimizations
1693 to be performed on the intermediate representation directly, without having
1694 to do extra analyses on the side before the transformation. A strong type
1695 system makes it easier to read the generated code and enables novel analyses
1696 and transformations that are not feasible to perform on normal three address
1697 code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000[diff] [blame]1698
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1699<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1700<h3>
1701 <a name="t_classifications">Type Classifications</a>
1702</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1703
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1704<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1705
1706<p>The types fall into a few useful classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1707
1708<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1709 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1710 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1711 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1712 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1713 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1714 </tr>
1715 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1716 <td><a href="#t_floating">floating point</a></td>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1717 <td><tt>half, float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1718 </tr>
1719 <tr>
1720 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1721 <td><a href="#t_integer">integer</a>,
1722 <a href="#t_floating">floating point</a>,
1723 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +0000[diff] [blame]1724 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]1725 <a href="#t_struct">structure</a>,
1726 <a href="#t_array">array</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1727 <a href="#t_label">label</a>,
1728 <a href="#t_metadata">metadata</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]1729 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1730 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1731 <tr>
1732 <td><a href="#t_primitive">primitive</a></td>
1733 <td><a href="#t_label">label</a>,
1734 <a href="#t_void">void</a>,
Tobias Grosser4c8c95b2010-12-28 20:29:31 +0000[diff] [blame]1735 <a href="#t_integer">integer</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1736 <a href="#t_floating">floating point</a>,
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1737 <a href="#t_x86mmx">x86mmx</a>,
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1738 <a href="#t_metadata">metadata</a>.</td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1739 </tr>
1740 <tr>
1741 <td><a href="#t_derived">derived</a></td>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1742 <td><a href="#t_array">array</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1743 <a href="#t_function">function</a>,
1744 <a href="#t_pointer">pointer</a>,
1745 <a href="#t_struct">structure</a>,
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1746 <a href="#t_vector">vector</a>,
1747 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +0000[diff] [blame]1748 </td>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1749 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]1750 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1751</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]1752
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1753<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
1754 important. Values of these types are the only ones which can be produced by
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1755 instructions.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1756
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1757</div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1758
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1759<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1760<h3>
1761 <a name="t_primitive">Primitive Types</a>
1762</h3>
Chris Lattner43542b32008-01-04 04:34:14 +0000[diff] [blame]1763
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1764<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1765
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1766<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1767 system.</p>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1768
1769<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1770<h4>
1771 <a name="t_integer">Integer Type</a>
1772</h4>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1773
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1774<div>
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1775
1776<h5>Overview:</h5>
1777<p>The integer type is a very simple type that simply specifies an arbitrary
1778 bit width for the integer type desired. Any bit width from 1 bit to
1779 2<sup>23</sup>-1 (about 8 million) can be specified.</p>
1780
1781<h5>Syntax:</h5>
1782<pre>
1783 iN
1784</pre>
1785
1786<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1787 value.</p>
1788
1789<h5>Examples:</h5>
1790<table class="layout">
1791 <tr class="layout">
1792 <td class="left"><tt>i1</tt></td>
1793 <td class="left">a single-bit integer.</td>
1794 </tr>
1795 <tr class="layout">
1796 <td class="left"><tt>i32</tt></td>
1797 <td class="left">a 32-bit integer.</td>
1798 </tr>
1799 <tr class="layout">
1800 <td class="left"><tt>i1942652</tt></td>
1801 <td class="left">a really big integer of over 1 million bits.</td>
1802 </tr>
1803</table>
1804
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1805</div>
1806
1807<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1808<h4>
1809 <a name="t_floating">Floating Point Types</a>
1810</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1811
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1812<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1813
1814<table>
1815 <tbody>
1816 <tr><th>Type</th><th>Description</th></tr>
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]1817 <tr><td><tt>half</tt></td><td>16-bit floating point value</td></tr>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1818 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1819 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1820 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1821 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1822 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1823 </tbody>
1824</table>
1825
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1826</div>
1827
1828<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1829<h4>
1830 <a name="t_x86mmx">X86mmx Type</a>
1831</h4>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1832
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1833<div>
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1834
1835<h5>Overview:</h5>
1836<p>The x86mmx type represents a value held in an MMX register on an x86 machine. The operations allowed on it are quite limited: parameters and return values, load and store, and bitcast. User-specified MMX instructions are represented as intrinsic or asm calls with arguments and/or results of this type. There are no arrays, vectors or constants of this type.</p>
1837
1838<h5>Syntax:</h5>
1839<pre>
Dale Johannesenb1f0ff12010-10-01 01:07:02 +0000[diff] [blame]1840 x86mmx
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]1841</pre>
1842
1843</div>
1844
1845<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1846<h4>
1847 <a name="t_void">Void Type</a>
1848</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1849
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1850<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1851
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1852<h5>Overview:</h5>
1853<p>The void type does not represent any value and has no size.</p>
1854
1855<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1856<pre>
1857 void
1858</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1859
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1860</div>
1861
1862<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1863<h4>
1864 <a name="t_label">Label Type</a>
1865</h4>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1866
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1867<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1868
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1869<h5>Overview:</h5>
1870<p>The label type represents code labels.</p>
1871
1872<h5>Syntax:</h5>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1873<pre>
1874 label
1875</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1876
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1877</div>
1878
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1879<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1880<h4>
1881 <a name="t_metadata">Metadata Type</a>
1882</h4>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1883
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1884<div>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1885
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1886<h5>Overview:</h5>
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]1887<p>The metadata type represents embedded metadata. No derived types may be
1888 created from metadata except for <a href="#t_function">function</a>
1889 arguments.
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1890
1891<h5>Syntax:</h5>
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1892<pre>
1893 metadata
1894</pre>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]1895
Nick Lewyckyadbc2842009-05-30 05:06:04 +0000[diff] [blame]1896</div>
1897
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1898</div>
Chris Lattner7824d182008-01-04 04:32:38 +0000[diff] [blame]1899
1900<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1901<h3>
1902 <a name="t_derived">Derived Types</a>
1903</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1904
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1905<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1906
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1907<p>The real power in LLVM comes from the derived types in the system. This is
1908 what allows a programmer to represent arrays, functions, pointers, and other
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]1909 useful types. Each of these types contain one or more element types which
1910 may be a primitive type, or another derived type. For example, it is
1911 possible to have a two dimensional array, using an array as the element type
1912 of another array.</p>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]1913
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1914<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1915<h4>
1916 <a name="t_aggregate">Aggregate Types</a>
1917</h4>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1918
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1919<div>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1920
1921<p>Aggregate Types are a subset of derived types that can contain multiple
Duncan Sands9aaec152011-12-14 15:44:20 +0000[diff] [blame]1922 member types. <a href="#t_array">Arrays</a> and
1923 <a href="#t_struct">structs</a> are aggregate types.
1924 <a href="#t_vector">Vectors</a> are not considered to be aggregate types.</p>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]1925
1926</div>
1927
Reid Spencer138249b2007-05-16 18:44:01 +0000[diff] [blame]1928<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1929<h4>
1930 <a name="t_array">Array Type</a>
1931</h4>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1932
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1933<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1934
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1935<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1936<p>The array type is a very simple derived type that arranges elements
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1937 sequentially in memory. The array type requires a size (number of elements)
1938 and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1939
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1940<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1941<pre>
1942 [&lt;# elements&gt; x &lt;elementtype&gt;]
1943</pre>
1944
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1945<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
1946 be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]1947
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]1948<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1949<table class="layout">
1950 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1951 <td class="left"><tt>[40 x i32]</tt></td>
1952 <td class="left">Array of 40 32-bit integer values.</td>
1953 </tr>
1954 <tr class="layout">
1955 <td class="left"><tt>[41 x i32]</tt></td>
1956 <td class="left">Array of 41 32-bit integer values.</td>
1957 </tr>
1958 <tr class="layout">
1959 <td class="left"><tt>[4 x i8]</tt></td>
1960 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1961 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1962</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1963<p>Here are some examples of multidimensional arrays:</p>
1964<table class="layout">
1965 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]1966 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1967 <td class="left">3x4 array of 32-bit integer values.</td>
1968 </tr>
1969 <tr class="layout">
1970 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1971 <td class="left">12x10 array of single precision floating point values.</td>
1972 </tr>
1973 <tr class="layout">
1974 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1975 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1976 </tr>
1977</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1978
Dan Gohmanc74bc282009-11-09 19:01:53 +0000[diff] [blame]1979<p>There is no restriction on indexing beyond the end of the array implied by
1980 a static type (though there are restrictions on indexing beyond the bounds
1981 of an allocated object in some cases). This means that single-dimension
1982 'variable sized array' addressing can be implemented in LLVM with a zero
1983 length array type. An implementation of 'pascal style arrays' in LLVM could
1984 use the type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]1985
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]1986</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]1987
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1988<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]1989<h4>
1990 <a name="t_function">Function Type</a>
1991</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1992
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]1993<div>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]1994
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]1995<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]1996<p>The function type can be thought of as a function signature. It consists of
1997 a return type and a list of formal parameter types. The return type of a
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]1998 function type is a first class type or a void type.</p>
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]1999
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2000<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2001<pre>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2002 &lt;returntype&gt; (&lt;parameter list&gt;)
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2003</pre>
2004
John Criswell4c0cf7f2005-10-24 16:17:18 +0000[diff] [blame]2005<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2006 specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
2007 which indicates that the function takes a variable number of arguments.
2008 Variable argument functions can access their arguments with
2009 the <a href="#int_varargs">variable argument handling intrinsic</a>
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2010 functions. '<tt>&lt;returntype&gt;</tt>' is any type except
Nick Lewycky93e06a52009-09-27 23:27:42 +0000[diff] [blame]2011 <a href="#t_label">label</a>.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]2012
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2013<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2014<table class="layout">
2015 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2016 <td class="left"><tt>i32 (i32)</tt></td>
2017 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2018 </td>
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2019 </tr><tr class="layout">
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2020 <td class="left"><tt>float&nbsp;(i16,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +0000[diff] [blame]2021 </tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2022 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]2023 an <tt>i16</tt> and a <a href="#t_pointer">pointer</a> to <tt>i32</tt>,
2024 returning <tt>float</tt>.
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2025 </td>
2026 </tr><tr class="layout">
2027 <td class="left"><tt>i32 (i8*, ...)</tt></td>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2028 <td class="left">A vararg function that takes at least one
2029 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
2030 which returns an integer. This is the signature for <tt>printf</tt> in
Reid Spencer58c08712006-12-31 07:18:34 +0000[diff] [blame]2031 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2032 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2033 </tr><tr class="layout">
2034 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Nick Lewycky14d1ccc2009-09-27 07:55:32 +0000[diff] [blame]2035 <td class="left">A function taking an <tt>i32</tt>, returning a
2036 <a href="#t_struct">structure</a> containing two <tt>i32</tt> values
Devang Patele3dfc1c2008-03-24 05:35:41 +0000[diff] [blame]2037 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2038 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2039</table>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]2040
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2041</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2042
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2043<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2044<h4>
2045 <a name="t_struct">Structure Type</a>
2046</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2047
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2048<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2049
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2050<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2051<p>The structure type is used to represent a collection of data members together
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2052 in memory. The elements of a structure may be any type that has a size.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2053
Jeffrey Yasskinf991bbb2010-01-11 19:19:26 +0000[diff] [blame]2054<p>Structures in memory are accessed using '<tt><a href="#i_load">load</a></tt>'
2055 and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field
2056 with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
2057 Structures in registers are accessed using the
2058 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' and
2059 '<tt><a href="#i_insertvalue">insertvalue</a></tt>' instructions.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2060
2061<p>Structures may optionally be "packed" structures, which indicate that the
2062 alignment of the struct is one byte, and that there is no padding between
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2063 the elements. In non-packed structs, padding between field types is inserted
2064 as defined by the TargetData string in the module, which is required to match
Chris Lattner7bd0ea32011-10-11 23:02:17 +0000[diff] [blame]2065 what the underlying code generator expects.</p>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2066
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2067<p>Structures can either be "literal" or "identified". A literal structure is
2068 defined inline with other types (e.g. <tt>{i32, i32}*</tt>) whereas identified
2069 types are always defined at the top level with a name. Literal types are
2070 uniqued by their contents and can never be recursive or opaque since there is
Chris Lattner32531732011-08-12 18:12:40 +0000[diff] [blame]2071 no way to write one. Identified types can be recursive, can be opaqued, and are
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2072 never uniqued.
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2073</p>
2074
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2075<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2076<pre>
Chris Lattner190552d2011-08-12 17:31:02 +0000[diff] [blame]2077 %T1 = type { &lt;type list&gt; } <i>; Identified normal struct type</i>
2078 %T2 = type &lt;{ &lt;type list&gt; }&gt; <i>; Identified packed struct type</i>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2079</pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2080
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2081<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2082<table class="layout">
2083 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2084 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
2085 <td class="left">A triple of three <tt>i32</tt> values</td>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2086 </tr>
2087 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]2088 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
2089 <td class="left">A pair, where the first element is a <tt>float</tt> and the
2090 second element is a <a href="#t_pointer">pointer</a> to a
2091 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
2092 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2093 </tr>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2094 <tr class="layout">
2095 <td class="left"><tt>&lt;{ i8, i32 }&gt;</tt></td>
2096 <td class="left">A packed struct known to be 5 bytes in size.</td>
2097 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2098</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2099
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2100</div>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2101
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2102<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2103<h4>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2104 <a name="t_opaque">Opaque Structure Types</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2105</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2106
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2107<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2108
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2109<h5>Overview:</h5>
Chris Lattner2a843822011-07-23 19:59:08 +0000[diff] [blame]2110<p>Opaque structure types are used to represent named structure types that do
2111 not have a body specified. This corresponds (for example) to the C notion of
2112 a forward declared structure.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2113
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2114<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2115<pre>
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2116 %X = type opaque
2117 %52 = type opaque
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2118</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2119
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2120<h5>Examples:</h5>
2121<table class="layout">
2122 <tr class="layout">
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2123 <td class="left"><tt>opaque</tt></td>
2124 <td class="left">An opaque type.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2125 </tr>
2126</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2127
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2128</div>
2129
Chris Lattnerb1ed91f2011-07-09 17:41:24 +0000[diff] [blame]2130
2131
Andrew Lenharth8df88e22006-12-08 17:13:00 +0000[diff] [blame]2132<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2133<h4>
2134 <a name="t_pointer">Pointer Type</a>
2135</h4>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2136
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2137<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2138
2139<h5>Overview:</h5>
Dan Gohman88481112010-02-25 16:50:07 +0000[diff] [blame]2140<p>The pointer type is used to specify memory locations.
2141 Pointers are commonly used to reference objects in memory.</p>
2142
2143<p>Pointer types may have an optional address space attribute defining the
2144 numbered address space where the pointed-to object resides. The default
2145 address space is number zero. The semantics of non-zero address
2146 spaces are target-specific.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2147
2148<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
2149 permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +0000[diff] [blame]2150
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2151<h5>Syntax:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]2152<pre>
2153 &lt;type&gt; *
2154</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2155
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]2156<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2157<table class="layout">
2158 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]2159 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2160 <td class="left">A <a href="#t_pointer">pointer</a> to <a
2161 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
2162 </tr>
2163 <tr class="layout">
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]2164 <td class="left"><tt>i32 (i32*) *</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2165 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]2166 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2167 <tt>i32</tt>.</td>
2168 </tr>
2169 <tr class="layout">
2170 <td class="left"><tt>i32 addrspace(5)*</tt></td>
2171 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
2172 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2173 </tr>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2174</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2175
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2176</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2177
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2178<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2179<h4>
2180 <a name="t_vector">Vector Type</a>
2181</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2182
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2183<div>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2184
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2185<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2186<p>A vector type is a simple derived type that represents a vector of elements.
2187 Vector types are used when multiple primitive data are operated in parallel
2188 using a single instruction (SIMD). A vector type requires a size (number of
Duncan Sands31c0e0e2009-11-27 13:38:03 +0000[diff] [blame]2189 elements) and an underlying primitive data type. Vector types are considered
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2190 <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2191
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2192<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2193<pre>
2194 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
2195</pre>
2196
Chris Lattnerf11031a2010-10-10 18:20:35 +0000[diff] [blame]2197<p>The number of elements is a constant integer value larger than 0; elementtype
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2198 may be any integer or floating point type, or a pointer to these types.
2199 Vectors of size zero are not allowed. </p>
Chris Lattner37b6b092005-04-25 17:34:15 +0000[diff] [blame]2200
Chris Lattnerc8cb6952004-08-12 19:12:28 +0000[diff] [blame]2201<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2202<table class="layout">
2203 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +0000[diff] [blame]2204 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
2205 <td class="left">Vector of 4 32-bit integer values.</td>
2206 </tr>
2207 <tr class="layout">
2208 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
2209 <td class="left">Vector of 8 32-bit floating-point values.</td>
2210 </tr>
2211 <tr class="layout">
2212 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
2213 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2214 </tr>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]2215 <tr class="layout">
2216 <td class="left"><tt>&lt;4 x i64*&gt;</tt></td>
2217 <td class="left">Vector of 4 pointers to 64-bit integer values.</td>
2218 </tr>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +0000[diff] [blame]2219</table>
Dan Gohman142ccc02009-01-24 15:58:40 +0000[diff] [blame]2220
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]2221</div>
2222
Bill Wendlingae8b5ea2011-07-31 06:47:33 +0000[diff] [blame]2223</div>
2224
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]2225</div>
2226
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2227<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2228<h2><a name="constants">Constants</a></h2>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2229<!-- *********************************************************************** -->
2230
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2231<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2232
2233<p>LLVM has several different basic types of constants. This section describes
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2234 them all and their syntax.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2235
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2236<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2237<h3>
2238 <a name="simpleconstants">Simple Constants</a>
2239</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2240
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2241<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2242
2243<dl>
2244 <dt><b>Boolean constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2245 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]2246 constants of the <tt><a href="#t_integer">i1</a></tt> type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2247
2248 <dt><b>Integer constants</b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2249 <dd>Standard integers (such as '4') are constants of
2250 the <a href="#t_integer">integer</a> type. Negative numbers may be used
2251 with integer types.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2252
2253 <dt><b>Floating point constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2254 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2255 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
2256 notation (see below). The assembler requires the exact decimal value of a
2257 floating-point constant. For example, the assembler accepts 1.25 but
2258 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
2259 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2260
2261 <dt><b>Null pointer constants</b></dt>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]2262 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2263 and must be of <a href="#t_pointer">pointer type</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2264</dl>
2265
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2266<p>The one non-intuitive notation for constants is the hexadecimal form of
2267 floating point constants. For example, the form '<tt>double
2268 0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
2269 '<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
2270 constants are required (and the only time that they are generated by the
2271 disassembler) is when a floating point constant must be emitted but it cannot
2272 be represented as a decimal floating point number in a reasonable number of
2273 digits. For example, NaN's, infinities, and other special values are
2274 represented in their IEEE hexadecimal format so that assembly and disassembly
2275 do not cause any bits to change in the constants.</p>
2276
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2277<p>When using the hexadecimal form, constants of types half, float, and double are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2278 represented using the 16-digit form shown above (which matches the IEEE754
Dan Gohman518cda42011-12-17 00:04:22 +0000[diff] [blame]2279 representation for double); half and float values must, however, be exactly
2280 representable as IEE754 half and single precision, respectively.
2281 Hexadecimal format is always used
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2282 for long double, and there are three forms of long double. The 80-bit format
2283 used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
2284 The 128-bit format used by PowerPC (two adjacent doubles) is represented
2285 by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
2286 is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
2287 currently supported target uses this format. Long doubles will only work if
2288 they match the long double format on your target. All hexadecimal formats
2289 are big-endian (sign bit at the left).</p>
2290
Dale Johannesen33e5c352010-10-01 00:48:59 +0000[diff] [blame]2291<p>There are no constants of type x86mmx.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2292</div>
2293
2294<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2295<h3>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]2296<a name="aggregateconstants"></a> <!-- old anchor -->
2297<a name="complexconstants">Complex Constants</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2298</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2299
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2300<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2301
Chris Lattner361bfcd2009-02-28 18:32:25 +0000[diff] [blame]2302<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2303 constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2304
2305<dl>
2306 <dt><b>Structure constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2307 <dd>Structure constants are represented with notation similar to structure
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2308 type definitions (a comma separated list of elements, surrounded by braces
2309 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
2310 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
2311 Structure constants must have <a href="#t_struct">structure type</a>, and
2312 the number and types of elements must match those specified by the
2313 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2314
2315 <dt><b>Array constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2316 <dd>Array constants are represented with notation similar to array type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2317 definitions (a comma separated list of elements, surrounded by square
2318 brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
2319 ]</tt>". Array constants must have <a href="#t_array">array type</a>, and
2320 the number and types of elements must match those specified by the
2321 type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2322
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2323 <dt><b>Vector constants</b></dt>
Reid Spencer404a3252007-02-15 03:07:05 +0000[diff] [blame]2324 <dd>Vector constants are represented with notation similar to vector type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2325 definitions (a comma separated list of elements, surrounded by
2326 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32
2327 42, i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must
2328 have <a href="#t_vector">vector type</a>, and the number and types of
2329 elements must match those specified by the type.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2330
2331 <dt><b>Zero initialization</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2332 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]2333 value to zero of <em>any</em> type, including scalar and
2334 <a href="#t_aggregate">aggregate</a> types.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2335 This is often used to avoid having to print large zero initializers
2336 (e.g. for large arrays) and is always exactly equivalent to using explicit
2337 zero initializers.</dd>
Nick Lewycky49f89192009-04-04 07:22:01 +0000[diff] [blame]2338
2339 <dt><b>Metadata node</b></dt>
Nick Lewycky8e2c4f42009-05-30 16:08:30 +0000[diff] [blame]2340 <dd>A metadata node is a structure-like constant with
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2341 <a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
2342 i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
2343 be interpreted as part of the instruction stream, metadata is a place to
2344 attach additional information such as debug info.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2345</dl>
2346
2347</div>
2348
2349<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2350<h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2351 <a name="globalconstants">Global Variable and Function Addresses</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2352</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2353
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2354<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2355
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2356<p>The addresses of <a href="#globalvars">global variables</a>
2357 and <a href="#functionstructure">functions</a> are always implicitly valid
2358 (link-time) constants. These constants are explicitly referenced when
2359 the <a href="#identifiers">identifier for the global</a> is used and always
2360 have <a href="#t_pointer">pointer</a> type. For example, the following is a
2361 legal LLVM file:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2362
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2363<pre class="doc_code">
Chris Lattner00538a12007-06-06 18:28:13 +0000[diff] [blame]2364@X = global i32 17
2365@Y = global i32 42
2366@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2367</pre>
2368
2369</div>
2370
2371<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2372<h3>
2373 <a name="undefvalues">Undefined Values</a>
2374</h3>
2375
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2376<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2377
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2378<p>The string '<tt>undef</tt>' can be used anywhere a constant is expected, and
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]2379 indicates that the user of the value may receive an unspecified bit-pattern.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2380 Undefined values may be of any type (other than '<tt>label</tt>'
2381 or '<tt>void</tt>') and be used anywhere a constant is permitted.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2382
Chris Lattner92ada5d2009-09-11 01:49:31 +0000[diff] [blame]2383<p>Undefined values are useful because they indicate to the compiler that the
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2384 program is well defined no matter what value is used. This gives the
2385 compiler more freedom to optimize. Here are some examples of (potentially
2386 surprising) transformations that are valid (in pseudo IR):</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2387
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2388
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2389<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2390 %A = add %X, undef
2391 %B = sub %X, undef
2392 %C = xor %X, undef
2393Safe:
2394 %A = undef
2395 %B = undef
2396 %C = undef
2397</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2398
2399<p>This is safe because all of the output bits are affected by the undef bits.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2400 Any output bit can have a zero or one depending on the input bits.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2401
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2402<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2403 %A = or %X, undef
2404 %B = and %X, undef
2405Safe:
2406 %A = -1
2407 %B = 0
2408Unsafe:
2409 %A = undef
2410 %B = undef
2411</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2412
2413<p>These logical operations have bits that are not always affected by the input.
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2414 For example, if <tt>%X</tt> has a zero bit, then the output of the
2415 '<tt>and</tt>' operation will always be a zero for that bit, no matter what
2416 the corresponding bit from the '<tt>undef</tt>' is. As such, it is unsafe to
2417 optimize or assume that the result of the '<tt>and</tt>' is '<tt>undef</tt>'.
2418 However, it is safe to assume that all bits of the '<tt>undef</tt>' could be
2419 0, and optimize the '<tt>and</tt>' to 0. Likewise, it is safe to assume that
2420 all the bits of the '<tt>undef</tt>' operand to the '<tt>or</tt>' could be
2421 set, allowing the '<tt>or</tt>' to be folded to -1.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2422
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2423<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2424 %A = select undef, %X, %Y
2425 %B = select undef, 42, %Y
2426 %C = select %X, %Y, undef
2427Safe:
2428 %A = %X (or %Y)
2429 %B = 42 (or %Y)
2430 %C = %Y
2431Unsafe:
2432 %A = undef
2433 %B = undef
2434 %C = undef
2435</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2436
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2437<p>This set of examples shows that undefined '<tt>select</tt>' (and conditional
2438 branch) conditions can go <em>either way</em>, but they have to come from one
2439 of the two operands. In the <tt>%A</tt> example, if <tt>%X</tt> and
2440 <tt>%Y</tt> were both known to have a clear low bit, then <tt>%A</tt> would
2441 have to have a cleared low bit. However, in the <tt>%C</tt> example, the
2442 optimizer is allowed to assume that the '<tt>undef</tt>' operand could be the
2443 same as <tt>%Y</tt>, allowing the whole '<tt>select</tt>' to be
2444 eliminated.</p>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2445
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2446<pre class="doc_code">
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2447 %A = xor undef, undef
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2448
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2449 %B = undef
2450 %C = xor %B, %B
2451
2452 %D = undef
2453 %E = icmp lt %D, 4
2454 %F = icmp gte %D, 4
2455
2456Safe:
2457 %A = undef
2458 %B = undef
2459 %C = undef
2460 %D = undef
2461 %E = undef
2462 %F = undef
2463</pre>
Chris Lattnerec72b9b2009-09-07 22:52:39 +0000[diff] [blame]2464
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2465<p>This example points out that two '<tt>undef</tt>' operands are not
2466 necessarily the same. This can be surprising to people (and also matches C
2467 semantics) where they assume that "<tt>X^X</tt>" is always zero, even
2468 if <tt>X</tt> is undefined. This isn't true for a number of reasons, but the
2469 short answer is that an '<tt>undef</tt>' "variable" can arbitrarily change
2470 its value over its "live range". This is true because the variable doesn't
2471 actually <em>have a live range</em>. Instead, the value is logically read
2472 from arbitrary registers that happen to be around when needed, so the value
2473 is not necessarily consistent over time. In fact, <tt>%A</tt> and <tt>%C</tt>
2474 need to have the same semantics or the core LLVM "replace all uses with"
2475 concept would not hold.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2476
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2477<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2478 %A = fdiv undef, %X
2479 %B = fdiv %X, undef
2480Safe:
2481 %A = undef
2482b: unreachable
2483</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2484
2485<p>These examples show the crucial difference between an <em>undefined
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2486 value</em> and <em>undefined behavior</em>. An undefined value (like
2487 '<tt>undef</tt>') is allowed to have an arbitrary bit-pattern. This means that
2488 the <tt>%A</tt> operation can be constant folded to '<tt>undef</tt>', because
2489 the '<tt>undef</tt>' could be an SNaN, and <tt>fdiv</tt> is not (currently)
2490 defined on SNaN's. However, in the second example, we can make a more
2491 aggressive assumption: because the <tt>undef</tt> is allowed to be an
2492 arbitrary value, we are allowed to assume that it could be zero. Since a
2493 divide by zero has <em>undefined behavior</em>, we are allowed to assume that
2494 the operation does not execute at all. This allows us to delete the divide and
2495 all code after it. Because the undefined operation "can't happen", the
2496 optimizer can assume that it occurs in dead code.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2497
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2498<pre class="doc_code">
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2499a: store undef -> %X
2500b: store %X -> undef
2501Safe:
2502a: &lt;deleted&gt;
2503b: unreachable
2504</pre>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2505
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2506<p>These examples reiterate the <tt>fdiv</tt> example: a store <em>of</em> an
2507 undefined value can be assumed to not have any effect; we can assume that the
2508 value is overwritten with bits that happen to match what was already there.
2509 However, a store <em>to</em> an undefined location could clobber arbitrary
2510 memory, therefore, it has undefined behavior.</p>
Chris Lattnera34a7182009-09-07 23:33:52 +0000[diff] [blame]2511
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2512</div>
2513
2514<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2515<h3>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2516 <a name="poisonvalues">Poison Values</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2517</h3>
2518
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2519<div>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2520
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2521<p>Poison values are similar to <a href="#undefvalues">undef values</a>, however
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2522 they also represent the fact that an instruction or constant expression which
2523 cannot evoke side effects has nevertheless detected a condition which results
2524 in undefined behavior.</p>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2525
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2526<p>There is currently no way of representing a poison value in the IR; they
Dan Gohmanac355aa2010-05-03 14:51:43 +0000[diff] [blame]2527 only exist when produced by operations such as
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2528 <a href="#i_add"><tt>add</tt></a> with the <tt>nsw</tt> flag.</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2529
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2530<p>Poison value behavior is defined in terms of value <i>dependence</i>:</p>
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2531
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2532<ul>
2533<li>Values other than <a href="#i_phi"><tt>phi</tt></a> nodes depend on
2534 their operands.</li>
2535
2536<li><a href="#i_phi"><tt>Phi</tt></a> nodes depend on the operand corresponding
2537 to their dynamic predecessor basic block.</li>
2538
2539<li>Function arguments depend on the corresponding actual argument values in
2540 the dynamic callers of their functions.</li>
2541
2542<li><a href="#i_call"><tt>Call</tt></a> instructions depend on the
2543 <a href="#i_ret"><tt>ret</tt></a> instructions that dynamically transfer
2544 control back to them.</li>
2545
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2546<li><a href="#i_invoke"><tt>Invoke</tt></a> instructions depend on the
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]2547 <a href="#i_ret"><tt>ret</tt></a>, <a href="#i_resume"><tt>resume</tt></a>,
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2548 or exception-throwing call instructions that dynamically transfer control
2549 back to them.</li>
2550
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2551<li>Non-volatile loads and stores depend on the most recent stores to all of the
2552 referenced memory addresses, following the order in the IR
2553 (including loads and stores implied by intrinsics such as
2554 <a href="#int_memcpy"><tt>@llvm.memcpy</tt></a>.)</li>
2555
Dan Gohman3513ea52010-05-03 14:59:34 +0000[diff] [blame]2556<!-- TODO: In the case of multiple threads, this only applies if the store
2557 "happens-before" the load or store. -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2558
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2559<!-- TODO: floating-point exception state -->
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2560
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2561<li>An instruction with externally visible side effects depends on the most
2562 recent preceding instruction with externally visible side effects, following
Dan Gohman6c858db2010-07-06 15:26:33 +0000[diff] [blame]2563 the order in the IR. (This includes
2564 <a href="#volatile">volatile operations</a>.)</li>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2565
Dan Gohman7292a752010-05-03 14:55:22 +0000[diff] [blame]2566<li>An instruction <i>control-depends</i> on a
2567 <a href="#terminators">terminator instruction</a>
2568 if the terminator instruction has multiple successors and the instruction
2569 is always executed when control transfers to one of the successors, and
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2570 may not be executed when control is transferred to another.</li>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2571
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2572<li>Additionally, an instruction also <i>control-depends</i> on a terminator
2573 instruction if the set of instructions it otherwise depends on would be
Chris Lattner0ab5e2c2011-04-15 05:18:47 +0000[diff] [blame]2574 different if the terminator had transferred control to a different
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2575 successor.</li>
2576
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2577<li>Dependence is transitive.</li>
2578
2579</ul>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2580
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2581<p>Poison Values have the same behavior as <a href="#undefvalues">undef values</a>,
2582 with the additional affect that any instruction which has a <i>dependence</i>
2583 on a poison value has undefined behavior.</p>
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2584
2585<p>Here are some examples:</p>
Dan Gohman48a25882010-04-26 20:54:53 +0000[diff] [blame]2586
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2587<pre class="doc_code">
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2588entry:
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2589 %poison = sub nuw i32 0, 1 ; Results in a poison value.
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2590 %still_poison = and i32 %poison, 0 ; 0, but also poison.
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2591 %poison_yet_again = getelementptr i32* @h, i32 %still_poison
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2592 store i32 0, i32* %poison_yet_again ; memory at @h[0] is poisoned
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2593
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2594 store i32 %poison, i32* @g ; Poison value stored to memory.
2595 %poison2 = load i32* @g ; Poison value loaded back from memory.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2596
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2597 store volatile i32 %poison, i32* @g ; External observation; undefined behavior.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2598
2599 %narrowaddr = bitcast i32* @g to i16*
2600 %wideaddr = bitcast i32* @g to i64*
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]2601 %poison3 = load i16* %narrowaddr ; Returns a poison value.
2602 %poison4 = load i64* %wideaddr ; Returns a poison value.
Dan Gohman2f1ae062010-04-28 00:49:41 +0000[diff] [blame]2603
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2604 %cmp = icmp slt i32 %poison, 0 ; Returns a poison value.
2605 br i1 %cmp, label %true, label %end ; Branch to either destination.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2606
2607true:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2608 store volatile i32 0, i32* @g ; This is control-dependent on %cmp, so
2609 ; it has undefined behavior.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2610 br label %end
2611
2612end:
2613 %p = phi i32 [ 0, %entry ], [ 1, %true ]
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2614 ; Both edges into this PHI are
2615 ; control-dependent on %cmp, so this
2616 ; always results in a poison value.
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2617
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2618 store volatile i32 0, i32* @g ; This would depend on the store in %true
2619 ; if %cmp is true, or the store in %entry
2620 ; otherwise, so this is undefined behavior.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2621
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2622 br i1 %cmp, label %second_true, label %second_end
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2623 ; The same branch again, but this time the
2624 ; true block doesn't have side effects.
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2625
2626second_true:
2627 ; No side effects!
Nick Lewycky9c876bf2011-05-16 19:29:30 +0000[diff] [blame]2628 ret void
Dan Gohmanc8454ee2011-04-12 23:05:59 +0000[diff] [blame]2629
2630second_end:
Dan Gohman5f115a72011-12-06 03:31:14 +0000[diff] [blame]2631 store volatile i32 0, i32* @g ; This time, the instruction always depends
2632 ; on the store in %end. Also, it is
2633 ; control-equivalent to %end, so this is
Dan Gohman32772f72011-12-06 03:35:58 +0000[diff] [blame]2634 ; well-defined (ignoring earlier undefined
2635 ; behavior in this example).
Dan Gohmanb8b85c12010-04-26 23:36:52 +0000[diff] [blame]2636</pre>
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2637
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]2638</div>
2639
2640<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2641<h3>
2642 <a name="blockaddress">Addresses of Basic Blocks</a>
2643</h3>
2644
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2645<div>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2646
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2647<p><b><tt>blockaddress(@function, %block)</tt></b></p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2648
2649<p>The '<tt>blockaddress</tt>' constant computes the address of the specified
Chris Lattner5c5f0ac2009-10-27 21:49:40 +0000[diff] [blame]2650 basic block in the specified function, and always has an i8* type. Taking
Chris Lattneraa99c942009-11-01 01:27:45 +0000[diff] [blame]2651 the address of the entry block is illegal.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2652
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2653<p>This value only has defined behavior when used as an operand to the
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2654 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>' instruction, or for
2655 comparisons against null. Pointer equality tests between labels addresses
2656 results in undefined behavior &mdash; though, again, comparison against null
2657 is ok, and no label is equal to the null pointer. This may be passed around
2658 as an opaque pointer sized value as long as the bits are not inspected. This
2659 allows <tt>ptrtoint</tt> and arithmetic to be performed on these values so
2660 long as the original value is reconstituted before the <tt>indirectbr</tt>
2661 instruction.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]2662
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2663<p>Finally, some targets may provide defined semantics when using the value as
2664 the operand to an inline assembly, but that is target specific.</p>
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]2665
2666</div>
2667
2668
2669<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2670<h3>
2671 <a name="constantexprs">Constant Expressions</a>
2672</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2673
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2674<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2675
2676<p>Constant expressions are used to allow expressions involving other constants
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2677 to be used as constants. Constant expressions may be of
2678 any <a href="#t_firstclass">first class</a> type and may involve any LLVM
2679 operation that does not have side effects (e.g. load and call are not
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]2680 supported). The following is the syntax for constant expressions:</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2681
2682<dl>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2683 <dt><b><tt>trunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2684 <dd>Truncate a constant to another type. The bit size of CST must be larger
2685 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2686
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2687 <dt><b><tt>zext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2688 <dd>Zero extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2689 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2690
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2691 <dt><b><tt>sext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2692 <dd>Sign extend a constant to another type. The bit size of CST must be
Duncan Sandsa522e562010-07-13 12:06:14 +0000[diff] [blame]2693 smaller than the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2694
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2695 <dt><b><tt>fptrunc (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2696 <dd>Truncate a floating point constant to another floating point type. The
2697 size of CST must be larger than the size of TYPE. Both types must be
2698 floating point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2699
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2700 <dt><b><tt>fpext (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2701 <dd>Floating point extend a constant to another type. The size of CST must be
2702 smaller or equal to the size of TYPE. Both types must be floating
2703 point.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2704
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2705 <dt><b><tt>fptoui (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2706 <dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2707 constant. TYPE must be a scalar or vector integer type. CST must be of
2708 scalar or vector floating point type. Both CST and TYPE must be scalars,
2709 or vectors of the same number of elements. If the value won't fit in the
2710 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2711
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2712 <dt><b><tt>fptosi (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2713 <dd>Convert a floating point constant to the corresponding signed integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2714 constant. TYPE must be a scalar or vector integer type. CST must be of
2715 scalar or vector floating point type. Both CST and TYPE must be scalars,
2716 or vectors of the same number of elements. If the value won't fit in the
2717 integer type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2718
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2719 <dt><b><tt>uitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2720 <dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2721 constant. TYPE must be a scalar or vector floating point type. CST must be
2722 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2723 vectors of the same number of elements. If the value won't fit in the
2724 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2725
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2726 <dt><b><tt>sitofp (CST to TYPE)</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2727 <dd>Convert a signed integer constant to the corresponding floating point
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2728 constant. TYPE must be a scalar or vector floating point type. CST must be
2729 of scalar or vector integer type. Both CST and TYPE must be scalars, or
2730 vectors of the same number of elements. If the value won't fit in the
2731 floating point type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]2732
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2733 <dt><b><tt>ptrtoint (CST to TYPE)</tt></b></dt>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2734 <dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2735 <tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
2736 type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
2737 make it fit in <tt>TYPE</tt>.</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2738
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2739 <dt><b><tt>inttoptr (CST to TYPE)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2740 <dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
2741 type. CST must be of integer type. The CST value is zero extended,
2742 truncated, or unchanged to make it fit in a pointer size. This one is
2743 <i>really</i> dangerous!</dd>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]2744
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2745 <dt><b><tt>bitcast (CST to TYPE)</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +0000[diff] [blame]2746 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
2747 are the same as those for the <a href="#i_bitcast">bitcast
2748 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2749
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2750 <dt><b><tt>getelementptr (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
2751 <dt><b><tt>getelementptr inbounds (CSTPTR, IDX0, IDX1, ...)</tt></b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2752 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2753 constants. As with the <a href="#i_getelementptr">getelementptr</a>
2754 instruction, the index list may have zero or more indexes, which are
2755 required to make sense for the type of "CSTPTR".</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2756
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2757 <dt><b><tt>select (COND, VAL1, VAL2)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2758 <dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2759
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2760 <dt><b><tt>icmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2761 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2762
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2763 <dt><b><tt>fcmp COND (VAL1, VAL2)</tt></b></dt>
Reid Spencer9965ee72006-12-04 19:23:19 +0000[diff] [blame]2764 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2765
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2766 <dt><b><tt>extractelement (VAL, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2767 <dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
2768 constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +0000[diff] [blame]2769
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2770 <dt><b><tt>insertelement (VAL, ELT, IDX)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2771 <dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
2772 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2773
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2774 <dt><b><tt>shufflevector (VEC1, VEC2, IDXMASK)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2775 <dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
2776 constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +0000[diff] [blame]2777
Nick Lewycky9ab9a7f2010-05-29 06:44:15 +0000[diff] [blame]2778 <dt><b><tt>extractvalue (VAL, IDX0, IDX1, ...)</tt></b></dt>
2779 <dd>Perform the <a href="#i_extractvalue">extractvalue operation</a> on
2780 constants. The index list is interpreted in a similar manner as indices in
2781 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2782 index value must be specified.</dd>
2783
2784 <dt><b><tt>insertvalue (VAL, ELT, IDX0, IDX1, ...)</tt></b></dt>
2785 <dd>Perform the <a href="#i_insertvalue">insertvalue operation</a> on
2786 constants. The index list is interpreted in a similar manner as indices in
2787 a '<a href="#i_getelementptr">getelementptr</a>' operation. At least one
2788 index value must be specified.</dd>
2789
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]2790 <dt><b><tt>OPCODE (LHS, RHS)</tt></b></dt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2791 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2792 be any of the <a href="#binaryops">binary</a>
2793 or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
2794 on operands are the same as those for the corresponding instruction
2795 (e.g. no bitwise operations on floating point values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2796</dl>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2797
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]2798</div>
Chris Lattnerb1652612004-03-08 16:49:10 +0000[diff] [blame]2799
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2800</div>
2801
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]2802<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2803<h2><a name="othervalues">Other Values</a></h2>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2804<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2805<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2806<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2807<h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2808<a name="inlineasm">Inline Assembler Expressions</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2809</h3>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2810
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2811<div>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2812
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2813<p>LLVM supports inline assembler expressions (as opposed
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2814 to <a href="#moduleasm">Module-Level Inline Assembly</a>) through the use of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2815 a special value. This value represents the inline assembler as a string
2816 (containing the instructions to emit), a list of operand constraints (stored
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2817 as a string), a flag that indicates whether or not the inline asm
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2818 expression has side effects, and a flag indicating whether the function
2819 containing the asm needs to align its stack conservatively. An example
2820 inline assembler expression is:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2821
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2822<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2823i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2824</pre>
2825
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2826<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
2827 a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
2828 have:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2829
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2830<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2831%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]2832</pre>
2833
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2834<p>Inline asms with side effects not visible in the constraint list must be
2835 marked as having side effects. This is done through the use of the
2836 '<tt>sideeffect</tt>' keyword, like so:</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2837
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2838<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]2839call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2840</pre>
2841
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2842<p>In some cases inline asms will contain code that will not work unless the
2843 stack is aligned in some way, such as calls or SSE instructions on x86,
2844 yet will not contain code that does that alignment within the asm.
2845 The compiler should make conservative assumptions about what the asm might
2846 contain and should generate its usual stack alignment code in the prologue
2847 if the '<tt>alignstack</tt>' keyword is present:</p>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2848
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2849<pre class="doc_code">
Dale Johannesen1cfb9582009-10-21 23:28:00 +0000[diff] [blame]2850call void asm alignstack "eieio", ""()
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2851</pre>
Dale Johannesen63c94fe2009-10-13 21:56:55 +0000[diff] [blame]2852
2853<p>If both keywords appear the '<tt>sideeffect</tt>' keyword must come
2854 first.</p>
2855
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2856<!--
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2857<p>TODO: The format of the asm and constraints string still need to be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]2858 documented here. Constraints on what can be done (e.g. duplication, moving,
2859 etc need to be documented). This is probably best done by reference to
2860 another document that covers inline asm from a holistic perspective.</p>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2861 -->
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2862
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2863<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2864<h4>
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2865 <a name="inlineasm_md">Inline Asm Metadata</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2866</h4>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2867
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2868<div>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2869
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2870<p>The call instructions that wrap inline asm nodes may have a
2871 "<tt>!srcloc</tt>" MDNode attached to it that contains a list of constant
2872 integers. If present, the code generator will use the integer as the
2873 location cookie value when report errors through the <tt>LLVMContext</tt>
2874 error reporting mechanisms. This allows a front-end to correlate backend
2875 errors that occur with inline asm back to the source code that produced it.
2876 For example:</p>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2877
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]2878<pre class="doc_code">
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2879call void asm sideeffect "something bad", ""()<b>, !srcloc !42</b>
2880...
2881!42 = !{ i32 1234567 }
2882</pre>
Chris Lattner51065562010-04-07 05:38:05 +0000[diff] [blame]2883
2884<p>It is up to the front-end to make sense of the magic numbers it places in the
Bill Wendlingad8b58b2011-11-30 21:52:43 +0000[diff] [blame]2885 IR. If the MDNode contains multiple constants, the code generator will use
Chris Lattner79ffdc72010-11-17 08:20:42 +0000[diff] [blame]2886 the one that corresponds to the line of the asm that the error occurs on.</p>
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]2887
2888</div>
2889
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2890</div>
2891
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2892<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]2893<h3>
2894 <a name="metadata">Metadata Nodes and Metadata Strings</a>
2895</h3>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2896
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]2897<div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2898
2899<p>LLVM IR allows metadata to be attached to instructions in the program that
2900 can convey extra information about the code to the optimizers and code
2901 generator. One example application of metadata is source-level debug
2902 information. There are two metadata primitives: strings and nodes. All
2903 metadata has the <tt>metadata</tt> type and is identified in syntax by a
2904 preceding exclamation point ('<tt>!</tt>').</p>
2905
2906<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2907 any character by escaping non-printable characters with "<tt>\xx</tt>" where
2908 "<tt>xx</tt>" is the two digit hex code. For example:
2909 "<tt>!"test\00"</tt>".</p>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2910
2911<p>Metadata nodes are represented with notation similar to structure constants
2912 (a comma separated list of elements, surrounded by braces and preceded by an
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2913 exclamation point). Metadata nodes can have any values as their operand. For
2914 example:</p>
2915
2916<div class="doc_code">
2917<pre>
2918!{ metadata !"test\00", i32 10}
2919</pre>
2920</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2921
2922<p>A <a href="#namedmetadatastructure">named metadata</a> is a collection of
2923 metadata nodes, which can be looked up in the module symbol table. For
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2924 example:</p>
2925
2926<div class="doc_code">
2927<pre>
2928!foo = metadata !{!4, !3}
2929</pre>
2930</div>
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]2931
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2932<p>Metadata can be used as function arguments. Here <tt>llvm.dbg.value</tt>
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2933 function is using two metadata arguments:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2934
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2935<div class="doc_code">
2936<pre>
2937call void @llvm.dbg.value(metadata !24, i64 0, metadata !25)
2938</pre>
2939</div>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2940
2941<p>Metadata can be attached with an instruction. Here metadata <tt>!21</tt> is
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2942 attached to the <tt>add</tt> instruction using the <tt>!dbg</tt>
2943 identifier:</p>
Devang Patel9984bd62010-03-04 23:44:48 +0000[diff] [blame]2944
Bill Wendlingc0e10672011-03-02 02:17:11 +0000[diff] [blame]2945<div class="doc_code">
2946<pre>
2947%indvar.next = add i64 %indvar, 1, !dbg !21
2948</pre>
2949</div>
2950
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2951<p>More information about specific metadata nodes recognized by the optimizers
2952 and code generator is found below.</p>
2953
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2954<!-- _______________________________________________________________________ -->
Peter Collingbourneec9ff672011-10-27 19:19:07 +0000[diff] [blame]2955<h4>
2956 <a name="tbaa">'<tt>tbaa</tt>' Metadata</a>
2957</h4>
2958
2959<div>
2960
2961<p>In LLVM IR, memory does not have types, so LLVM's own type system is not
2962 suitable for doing TBAA. Instead, metadata is added to the IR to describe
2963 a type system of a higher level language. This can be used to implement
2964 typical C/C++ TBAA, but it can also be used to implement custom alias
2965 analysis behavior for other languages.</p>
2966
2967<p>The current metadata format is very simple. TBAA metadata nodes have up to
2968 three fields, e.g.:</p>
2969
2970<div class="doc_code">
2971<pre>
2972!0 = metadata !{ metadata !"an example type tree" }
2973!1 = metadata !{ metadata !"int", metadata !0 }
2974!2 = metadata !{ metadata !"float", metadata !0 }
2975!3 = metadata !{ metadata !"const float", metadata !2, i64 1 }
2976</pre>
2977</div>
2978
2979<p>The first field is an identity field. It can be any value, usually
2980 a metadata string, which uniquely identifies the type. The most important
2981 name in the tree is the name of the root node. Two trees with
2982 different root node names are entirely disjoint, even if they
2983 have leaves with common names.</p>
2984
2985<p>The second field identifies the type's parent node in the tree, or
2986 is null or omitted for a root node. A type is considered to alias
2987 all of its descendants and all of its ancestors in the tree. Also,
2988 a type is considered to alias all types in other trees, so that
2989 bitcode produced from multiple front-ends is handled conservatively.</p>
2990
2991<p>If the third field is present, it's an integer which if equal to 1
2992 indicates that the type is "constant" (meaning
2993 <tt>pointsToConstantMemory</tt> should return true; see
2994 <a href="AliasAnalysis.html#OtherItfs">other useful
2995 <tt>AliasAnalysis</tt> methods</a>).</p>
2996
2997</div>
2998
Bill Wendlingb6c22202011-11-30 21:43:43 +0000[diff] [blame]2999<!-- _______________________________________________________________________ -->
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3000<h4>
3001 <a name="fpaccuracy">'<tt>fpaccuracy</tt>' Metadata</a>
3002</h4>
3003
3004<div>
3005
3006<p><tt>fpaccuracy</tt> metadata may be attached to any instruction of floating
3007 point type. It expresses the maximum relative error of the result of
3008 that instruction, in ULPs. ULP is defined as follows:</p>
3009
Bill Wendling302d7ce2011-11-09 19:33:56 +0000[diff] [blame]3010<blockquote>
3011
3012<p>If <tt>x</tt> is a real number that lies between two finite consecutive
3013 floating-point numbers <tt>a</tt> and <tt>b</tt>, without being equal to one
3014 of them, then <tt>ulp(x) = |b - a|</tt>, otherwise <tt>ulp(x)</tt> is the
3015 distance between the two non-equal finite floating-point numbers nearest
3016 <tt>x</tt>. Moreover, <tt>ulp(NaN)</tt> is <tt>NaN</tt>.</p>
3017
3018</blockquote>
Peter Collingbournef7d1e7b2011-10-27 19:19:14 +0000[diff] [blame]3019
3020<p>The maximum relative error may be any rational number. The metadata node
3021 shall consist of a pair of unsigned integers respectively representing
3022 the numerator and denominator. For example, 2.5 ULP:</p>
3023
3024<div class="doc_code">
3025<pre>
3026!0 = metadata !{ i32 5, i32 2 }
3027</pre>
3028</div>
3029
3030</div>
3031
Chris Lattnerc2f8f162010-01-15 21:50:19 +0000[diff] [blame]3032</div>
3033
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3034</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3035
3036<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3037<h2>
Bill Wendling911fdf42012-02-11 11:59:36 +0000[diff] [blame^]3038 <a name="module_flags">Module Flags Metadata</a>
3039</h2>
3040<!-- *********************************************************************** -->
3041
3042<div>
3043
3044<p>Information about the module as a whole is difficult to convey to LLVM's
3045 subsystems. The LLVM IR isn't sufficient to transmit this
3046 information. The <tt>llvm.module.flags</tt> named metadata exists in order to
3047 facilitate this. These flags are in the form of key / value pairs &mdash;
3048 much like a dictionary &mdash; making it easy for any subsystem who cares
3049 about a flag to look it up.</p>
3050
3051<p>The <tt>llvm.module.flags</tt> metadata contains a list of metadata
3052 triplets. Each triplet has the following form:</p>
3053
3054<ul>
3055 <li>The first element is a <i>behavior</i> flag, which specifies the behavior
3056 when two (or more) modules are merged together, and it encounters two (or
3057 more) metadata with the same ID. The supported behaviors are described
3058 below.</li>
3059
3060 <li>The second element is a metadata string that is a unique ID for the
3061 metadata. How each ID is interpreted is documented below.</li>
3062
3063 <li>The third element is the value of the flag.</li>
3064</ul>
3065
3066<p>When two (or more) modules are merged together, the resulting
3067 <tt>llvm.module.flags</tt> metadata is the union of the
3068 modules' <tt>llvm.module.flags</tt> metadata. The only exception being a flag
3069 with the <i>Override</i> behavior, which may override another flag's value
3070 (see below).</p>
3071
3072<p>The following behaviors are supported:</p>
3073
3074<table border="1" cellspacing="0" cellpadding="4">
3075 <tbody>
3076 <tr>
3077 <th>Value</th>
3078 <th>Behavior</th>
3079 </tr>
3080 <tr>
3081 <td>1</td>
3082 <td align="left">
3083 <dt><b>Error</b></dt>
3084 <dd>Emits an error if two values disagree. It is an error to have an ID
3085 with both an Error and a Warning behavior.</dd>
3086 </td>
3087 </tr>
3088 <tr>
3089 <td>2</td>
3090 <td align="left">
3091 <dt><b>Warning</b></dt>
3092 <dd>Emits a warning if two values disagree.</dd>
3093 </td>
3094 </tr>
3095 <tr>
3096 <td>3</td>
3097 <td align="left">
3098 <dt><b>Require</b></dt>
3099 <dd>Emits an error when the specified value is not present or doesn't
3100 have the specified value. It is an error for two (or more)
3101 <tt>llvm.module.flags</tt> with the same ID to have the Require
3102 behavior but different values. There may be multiple Require flags
3103 per ID.</dd>
3104 </td>
3105 </tr>
3106 <tr>
3107 <td>4</td>
3108 <td align="left">
3109 <dt><b>Override</b></dt>
3110 <dd>Uses the specified value if the two values disagree. It is an error
3111 for two (or more) <tt>llvm.module.flags</tt> with the same ID to
3112 have the Override behavior but different values.</dd>
3113 </td>
3114 </tr>
3115 </tbody>
3116</table>
3117
3118<p>An example of module flags:</p>
3119
3120<pre class="doc_code">
3121!0 = metadata !{ i32 1, metadata !"foo", i32 1 }
3122!1 = metadata !{ i32 4, metadata !"bar", i32 37 }
3123!2 = metadata !{ i32 2, metadata !"qux", i32 42 }
3124!3 = metadata !{ i32 3, metadata !"qux",
3125 metadata !{
3126 metadata !"foo", i32 1
3127 }
3128}
3129!llvm.module.flags = !{ !0, !1, !2, !3 }
3130</pre>
3131
3132<ul>
3133 <li><p>Metadata <tt>!0</tt> has the ID <tt>!"foo"</tt> and the value '1'. The
3134 behavior if two or more <tt>!"foo"</tt> flags are seen is to emit an
3135 error if their values are not equal.</p></li>
3136
3137 <li><p>Metadata <tt>!1</tt> has the ID <tt>!"bar"</tt> and the value '37'. The
3138 behavior if two or more <tt>!"bar"</tt> flags are seen is to use the
3139 value '37' if their values are not equal.</p></li>
3140
3141 <li><p>Metadata <tt>!2</tt> has the ID <tt>!"qux"</tt> and the value '42'. The
3142 behavior if two or more <tt>!"qux"</tt> flags are seen is to emit a
3143 warning if their values are not equal.</p></li>
3144
3145 <li><p>Metadata <tt>!3</tt> has the ID <tt>!"qux"</tt> and the value:</p>
3146
3147<pre class="doc_code">
3148metadata !{ metadata !"foo", i32 1 }
3149</pre>
3150 <p>The behavior is to emit an error if the <tt>llvm.module.flags</tt> does
3151 not contain a flag with the ID <tt>!"foo"</tt> that has the value
3152 '1'. If two or more <tt>!"qux"</tt> flags exist, then they must have
3153 the same value or an error will be issued.</p></li>
3154</ul>
3155
3156</div>
3157
3158<!-- *********************************************************************** -->
3159<h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3160 <a name="intrinsic_globals">Intrinsic Global Variables</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3161</h2>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3162<!-- *********************************************************************** -->
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3163<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3164<p>LLVM has a number of "magic" global variables that contain data that affect
3165code generation or other IR semantics. These are documented here. All globals
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3166of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
3167section and all globals that start with "<tt>llvm.</tt>" are reserved for use
3168by LLVM.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3169
3170<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3171<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3172<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3173</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3174
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3175<div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3176
3177<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
3178href="#linkage_appending">appending linkage</a>. This array contains a list of
3179pointers to global variables and functions which may optionally have a pointer
3180cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
3181
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3182<div class="doc_code">
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3183<pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3184@X = global i8 4
3185@Y = global i32 123
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3186
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3187@llvm.used = appending global [2 x i8*] [
3188 i8* @X,
3189 i8* bitcast (i32* @Y to i8*)
3190], section "llvm.metadata"
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3191</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3192</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3193
3194<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3195 compiler, assembler, and linker are required to treat the symbol as if there
3196 is a reference to the global that it cannot see. For example, if a variable
3197 has internal linkage and no references other than that from
3198 the <tt>@llvm.used</tt> list, it cannot be deleted. This is commonly used to
3199 represent references from inline asms and other things the compiler cannot
3200 "see", and corresponds to "<tt>attribute((used))</tt>" in GNU C.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3201
3202<p>On some targets, the code generator must emit a directive to the assembler or
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3203 object file to prevent the assembler and linker from molesting the
3204 symbol.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3205
3206</div>
3207
3208<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3209<h3>
3210 <a name="intg_compiler_used">
3211 The '<tt>llvm.compiler.used</tt>' Global Variable
3212 </a>
3213</h3>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3214
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3215<div>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3216
3217<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3218 <tt>@llvm.used</tt> directive, except that it only prevents the compiler from
3219 touching the symbol. On targets that support it, this allows an intelligent
3220 linker to optimize references to the symbol without being impeded as it would
3221 be by <tt>@llvm.used</tt>.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3222
3223<p>This is a rare construct that should only be used in rare circumstances, and
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3224 should not be exposed to source languages.</p>
Chris Lattner58f9bb22009-07-20 06:14:25 +0000[diff] [blame]3225
3226</div>
3227
3228<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3229<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3230<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3231</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3232
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3233<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3234
3235<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3236<pre>
3237%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3238@llvm.global_ctors = appending global [1 x %0] [%0 { i32 65535, void ()* @ctor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3239</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3240</div>
3241
3242<p>The <tt>@llvm.global_ctors</tt> array contains a list of constructor
3243 functions and associated priorities. The functions referenced by this array
3244 will be called in ascending order of priority (i.e. lowest first) when the
3245 module is loaded. The order of functions with the same priority is not
3246 defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3247
3248</div>
3249
3250<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3251<h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3252<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3253</h3>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3254
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3255<div>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3256
3257<div class="doc_code">
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3258<pre>
3259%0 = type { i32, void ()* }
David Chisnallb492b812010-04-30 19:27:35 +0000[diff] [blame]3260@llvm.global_dtors = appending global [1 x %0] [%0 { i32 65535, void ()* @dtor }]
David Chisnalla9d4a6f2010-04-30 19:23:49 +0000[diff] [blame]3261</pre>
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3262</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3263
Bill Wendling1654bb22011-11-08 00:32:45 +0000[diff] [blame]3264<p>The <tt>@llvm.global_dtors</tt> array contains a list of destructor functions
3265 and associated priorities. The functions referenced by this array will be
3266 called in descending order of priority (i.e. highest first) when the module
3267 is loaded. The order of functions with the same priority is not defined.</p>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3268
3269</div>
3270
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3271</div>
Chris Lattnerae76db52009-07-20 05:55:19 +0000[diff] [blame]3272
Chris Lattner98f013c2006-01-25 23:47:57 +0000[diff] [blame]3273<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3274<h2><a name="instref">Instruction Reference</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3275<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3276
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3277<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3278
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3279<p>The LLVM instruction set consists of several different classifications of
3280 instructions: <a href="#terminators">terminator
3281 instructions</a>, <a href="#binaryops">binary instructions</a>,
3282 <a href="#bitwiseops">bitwise binary instructions</a>,
3283 <a href="#memoryops">memory instructions</a>, and
3284 <a href="#otherops">other instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3285
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3286<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3287<h3>
3288 <a name="terminators">Terminator Instructions</a>
3289</h3>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3290
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3291<div>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3292
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3293<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
3294 in a program ends with a "Terminator" instruction, which indicates which
3295 block should be executed after the current block is finished. These
3296 terminator instructions typically yield a '<tt>void</tt>' value: they produce
3297 control flow, not values (the one exception being the
3298 '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
3299
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3300<p>The terminator instructions are:
3301 '<a href="#i_ret"><tt>ret</tt></a>',
3302 '<a href="#i_br"><tt>br</tt></a>',
3303 '<a href="#i_switch"><tt>switch</tt></a>',
3304 '<a href="#i_indirectbr"><tt>indirectbr</tt></a>',
3305 '<a href="#i_invoke"><tt>invoke</tt></a>',
Chris Lattnerd3d65ab2011-08-02 20:29:13 +0000[diff] [blame]3306 '<a href="#i_resume"><tt>resume</tt></a>', and
3307 '<a href="#i_unreachable"><tt>unreachable</tt></a>'.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +0000[diff] [blame]3308
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3309<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3310<h4>
3311 <a name="i_ret">'<tt>ret</tt>' Instruction</a>
3312</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3313
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3314<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3315
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3316<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3317<pre>
3318 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]3319 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3320</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3321
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3322<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3323<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
3324 a value) from a function back to the caller.</p>
3325
3326<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
3327 value and then causes control flow, and one that just causes control flow to
3328 occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3329
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3330<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3331<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
3332 return value. The type of the return value must be a
3333 '<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]3334
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3335<p>A function is not <a href="#wellformed">well formed</a> if it it has a
3336 non-void return type and contains a '<tt>ret</tt>' instruction with no return
3337 value or a return value with a type that does not match its type, or if it
3338 has a void return type and contains a '<tt>ret</tt>' instruction with a
3339 return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3340
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3341<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3342<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
3343 the calling function's context. If the caller is a
3344 "<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
3345 instruction after the call. If the caller was an
3346 "<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
3347 the beginning of the "normal" destination block. If the instruction returns
3348 a value, that value shall set the call or invoke instruction's return
3349 value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3350
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3351<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +0000[diff] [blame]3352<pre>
3353 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]3354 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +0000[diff] [blame]3355 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3356</pre>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]3357
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3358</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3359<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3360<h4>
3361 <a name="i_br">'<tt>br</tt>' Instruction</a>
3362</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3363
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3364<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3365
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3366<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3367<pre>
Bill Wendling16b86742011-07-26 10:41:15 +0000[diff] [blame]3368 br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;
3369 br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3370</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3371
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3372<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3373<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
3374 different basic block in the current function. There are two forms of this
3375 instruction, corresponding to a conditional branch and an unconditional
3376 branch.</p>
3377
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3378<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3379<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
3380 '<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
3381 of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
3382 target.</p>
3383
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3384<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3385<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3386 argument is evaluated. If the value is <tt>true</tt>, control flows to the
3387 '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
3388 control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
3389
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3390<h5>Example:</h5>
Bill Wendling30235112009-07-20 02:39:26 +0000[diff] [blame]3391<pre>
3392Test:
3393 %cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
3394 br i1 %cond, label %IfEqual, label %IfUnequal
3395IfEqual:
3396 <a href="#i_ret">ret</a> i32 1
3397IfUnequal:
3398 <a href="#i_ret">ret</a> i32 0
3399</pre>
3400
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3401</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3402
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3403<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3404<h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3405 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3406</h4>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3407
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3408<div>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3409
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3410<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3411<pre>
3412 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
3413</pre>
3414
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3415<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3416<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3417 several different places. It is a generalization of the '<tt>br</tt>'
3418 instruction, allowing a branch to occur to one of many possible
3419 destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3420
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3421<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3422<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3423 comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
3424 and an array of pairs of comparison value constants and '<tt>label</tt>'s.
3425 The table is not allowed to contain duplicate constant entries.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3426
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3427<h5>Semantics:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]3428<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3429 destinations. When the '<tt>switch</tt>' instruction is executed, this table
3430 is searched for the given value. If the value is found, control flow is
Benjamin Kramer0f420382009-10-12 14:46:08 +0000[diff] [blame]3431 transferred to the corresponding destination; otherwise, control flow is
3432 transferred to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3433
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3434<h5>Implementation:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3435<p>Depending on properties of the target machine and the particular
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3436 <tt>switch</tt> instruction, this instruction may be code generated in
3437 different ways. For example, it could be generated as a series of chained
3438 conditional branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3439
3440<h5>Example:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3441<pre>
3442 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]3443 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3444 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3445
3446 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3447 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +0000[diff] [blame]3448
3449 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +0000[diff] [blame]3450 switch i32 %val, label %otherwise [ i32 0, label %onzero
3451 i32 1, label %onone
3452 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3453</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3454
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3455</div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3456
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3457
3458<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3459<h4>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3460 <a name="i_indirectbr">'<tt>indirectbr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3461</h4>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3462
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3463<div>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3464
3465<h5>Syntax:</h5>
3466<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3467 indirectbr &lt;somety&gt;* &lt;address&gt;, [ label &lt;dest1&gt;, label &lt;dest2&gt;, ... ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3468</pre>
3469
3470<h5>Overview:</h5>
3471
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3472<p>The '<tt>indirectbr</tt>' instruction implements an indirect branch to a label
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3473 within the current function, whose address is specified by
Chris Lattnere4801f72009-10-27 21:01:34 +0000[diff] [blame]3474 "<tt>address</tt>". Address must be derived from a <a
3475 href="#blockaddress">blockaddress</a> constant.</p>
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3476
3477<h5>Arguments:</h5>
3478
3479<p>The '<tt>address</tt>' argument is the address of the label to jump to. The
3480 rest of the arguments indicate the full set of possible destinations that the
3481 address may point to. Blocks are allowed to occur multiple times in the
3482 destination list, though this isn't particularly useful.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3483
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3484<p>This destination list is required so that dataflow analysis has an accurate
3485 understanding of the CFG.</p>
3486
3487<h5>Semantics:</h5>
3488
3489<p>Control transfers to the block specified in the address argument. All
3490 possible destination blocks must be listed in the label list, otherwise this
3491 instruction has undefined behavior. This implies that jumps to labels
3492 defined in other functions have undefined behavior as well.</p>
3493
3494<h5>Implementation:</h5>
3495
3496<p>This is typically implemented with a jump through a register.</p>
3497
3498<h5>Example:</h5>
3499<pre>
Chris Lattnerd04cb6d2009-10-28 00:19:10 +0000[diff] [blame]3500 indirectbr i8* %Addr, [ label %bb1, label %bb2, label %bb3 ]
Chris Lattner3ed871f2009-10-27 19:13:16 +0000[diff] [blame]3501</pre>
3502
3503</div>
3504
3505
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3506<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3507<h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3508 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3509</h4>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3510
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3511<div>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3512
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3513<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3514<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3515 &lt;result&gt; = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ptr to function ty&gt; &lt;function ptr val&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattner6b7a0082006-05-14 18:23:06 +0000[diff] [blame]3516 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3517</pre>
3518
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]3519<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3520<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3521 function, with the possibility of control flow transfer to either the
3522 '<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
3523 function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
3524 control flow will return to the "normal" label. If the callee (or any
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3525 indirect callees) returns via the "<a href="#i_resume"><tt>resume</tt></a>"
3526 instruction or other exception handling mechanism, control is interrupted and
3527 continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3528
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3529<p>The '<tt>exception</tt>' label is a
3530 <i><a href="ExceptionHandling.html#overview">landing pad</a></i> for the
3531 exception. As such, '<tt>exception</tt>' label is required to have the
3532 "<a href="#i_landingpad"><tt>landingpad</tt></a>" instruction, which contains
Chad Rosierc28f3e92011-12-09 02:00:44 +0000[diff] [blame]3533 the information about the behavior of the program after unwinding
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3534 happens, as its first non-PHI instruction. The restrictions on the
3535 "<tt>landingpad</tt>" instruction's tightly couples it to the
3536 "<tt>invoke</tt>" instruction, so that the important information contained
3537 within the "<tt>landingpad</tt>" instruction can't be lost through normal
3538 code motion.</p>
3539
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3540<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3541<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3542
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3543<ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3544 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
3545 convention</a> the call should use. If none is specified, the call
3546 defaults to using C calling conventions.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3547
3548 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3549 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
3550 '<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]3551
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3552 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3553 function value being invoked. In most cases, this is a direct function
3554 invocation, but indirect <tt>invoke</tt>s are just as possible, branching
3555 off an arbitrary pointer to function value.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3556
3557 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3558 function to be invoked. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3559
3560 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]3561 signature argument types and parameter attributes. All arguments must be
3562 of <a href="#t_firstclass">first class</a> type. If the function
3563 signature indicates the function accepts a variable number of arguments,
3564 the extra arguments can be specified.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3565
3566 <li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3567 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3568
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]3569 <li>'<tt>exception label</tt>': the label reached when a callee returns via
3570 the <a href="#i_resume"><tt>resume</tt></a> instruction or other exception
3571 handling mechanism.</li>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3572
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]3573 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3574 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
3575 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3576</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3577
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3578<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3579<p>This instruction is designed to operate as a standard
3580 '<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
3581 primary difference is that it establishes an association with a label, which
3582 is used by the runtime library to unwind the stack.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3583
3584<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3585 cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
3586 exception. Additionally, this is important for implementation of
3587 '<tt>catch</tt>' clauses in high-level languages that support them.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3588
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3589<p>For the purposes of the SSA form, the definition of the value returned by the
3590 '<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
3591 block to the "normal" label. If the callee unwinds then no return value is
3592 available.</p>
Dan Gohman9069d892009-05-22 21:47:08 +0000[diff] [blame]3593
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3594<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +0000[diff] [blame]3595<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3596 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3597 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +0000[diff] [blame]3598 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]3599 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3600</pre>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3601
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3602</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3603
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3604 <!-- _______________________________________________________________________ -->
3605
3606<h4>
3607 <a name="i_resume">'<tt>resume</tt>' Instruction</a>
3608</h4>
3609
3610<div>
3611
3612<h5>Syntax:</h5>
3613<pre>
3614 resume &lt;type&gt; &lt;value&gt;
3615</pre>
3616
3617<h5>Overview:</h5>
3618<p>The '<tt>resume</tt>' instruction is a terminator instruction that has no
3619 successors.</p>
3620
3621<h5>Arguments:</h5>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3622<p>The '<tt>resume</tt>' instruction requires one argument, which must have the
Bill Wendlingc5a13612011-08-03 18:37:32 +0000[diff] [blame]3623 same type as the result of any '<tt>landingpad</tt>' instruction in the same
3624 function.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3625
3626<h5>Semantics:</h5>
3627<p>The '<tt>resume</tt>' instruction resumes propagation of an existing
3628 (in-flight) exception whose unwinding was interrupted with
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3629 a <a href="#i_landingpad"><tt>landingpad</tt></a> instruction.</p>
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3630
3631<h5>Example:</h5>
3632<pre>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]3633 resume { i8*, i32 } %exn
Bill Wendlingf891bf82011-07-31 06:30:59 +0000[diff] [blame]3634</pre>
3635
3636</div>
3637
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3638<!-- _______________________________________________________________________ -->
3639
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3640<h4>
3641 <a name="i_unreachable">'<tt>unreachable</tt>' Instruction</a>
3642</h4>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3643
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3644<div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3645
3646<h5>Syntax:</h5>
3647<pre>
3648 unreachable
3649</pre>
3650
3651<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3652<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3653 instruction is used to inform the optimizer that a particular portion of the
3654 code is not reachable. This can be used to indicate that the code after a
3655 no-return function cannot be reached, and other facts.</p>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3656
3657<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3658<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3659
Chris Lattner08b7d5b2004-10-16 18:04:13 +0000[diff] [blame]3660</div>
3661
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3662</div>
3663
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3664<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3665<h3>
3666 <a name="binaryops">Binary Operations</a>
3667</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3668
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3669<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3670
3671<p>Binary operators are used to do most of the computation in a program. They
3672 require two operands of the same type, execute an operation on them, and
3673 produce a single value. The operands might represent multiple data, as is
3674 the case with the <a href="#t_vector">vector</a> data type. The result value
3675 has the same type as its operands.</p>
3676
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3677<p>There are several different binary operators:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3678
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3679<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3680<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3681 <a name="i_add">'<tt>add</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3682</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3683
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3684<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3685
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3686<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3687<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3688 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3689 &lt;result&gt; = add nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3690 &lt;result&gt; = add nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3691 &lt;result&gt; = add nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3692</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3693
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3694<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3695<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3696
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3697<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3698<p>The two arguments to the '<tt>add</tt>' instruction must
3699 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3700 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3701
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3702<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3703<p>The value produced is the integer sum of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3704
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3705<p>If the sum has unsigned overflow, the result returned is the mathematical
3706 result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3707
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3708<p>Because LLVM integers use a two's complement representation, this instruction
3709 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3710
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3711<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3712 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3713 <tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3714 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3715 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3716
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3717<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3718<pre>
3719 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3720</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3721
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3722</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3723
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3724<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3725<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3726 <a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3727</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3728
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3729<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3730
3731<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3732<pre>
3733 &lt;result&gt; = fadd &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3734</pre>
3735
3736<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3737<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
3738
3739<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3740<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3741 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3742 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3743
3744<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3745<p>The value produced is the floating point sum of the two operands.</p>
3746
3747<h5>Example:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3748<pre>
3749 &lt;result&gt; = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
3750</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3751
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3752</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3753
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3754<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3755<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3756 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3757</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3758
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3759<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3760
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3761<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3762<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3763 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3764 &lt;result&gt; = sub nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3765 &lt;result&gt; = sub nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3766 &lt;result&gt; = sub nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3767</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3768
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3769<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3770<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3771 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3772
3773<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3774 '<tt>neg</tt>' instruction present in most other intermediate
3775 representations.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3776
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3777<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3778<p>The two arguments to the '<tt>sub</tt>' instruction must
3779 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3780 integer values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3781
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3782<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3783<p>The value produced is the integer difference of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3784
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3785<p>If the difference has unsigned overflow, the result returned is the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3786 mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
3787 result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3788
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3789<p>Because LLVM integers use a two's complement representation, this instruction
3790 is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3791
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3792<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3793 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3794 <tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3795 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3796 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3797
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3798<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000[diff] [blame]3799<pre>
3800 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]3801 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3802</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3803
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3804</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3805
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3806<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3807<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3808 <a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3809</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3810
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3811<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3812
3813<h5>Syntax:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3814<pre>
3815 &lt;result&gt; = fsub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3816</pre>
3817
3818<h5>Overview:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3819<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3820 operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3821
3822<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3823 '<tt>fneg</tt>' instruction present in most other intermediate
3824 representations.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3825
3826<h5>Arguments:</h5>
Bill Wendling972b7202009-07-20 02:32:41 +0000[diff] [blame]3827<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3828 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3829 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3830
3831<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3832<p>The value produced is the floating point difference of the two operands.</p>
3833
3834<h5>Example:</h5>
3835<pre>
3836 &lt;result&gt; = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
3837 &lt;result&gt; = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
3838</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3839
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3840</div>
3841
3842<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3843<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3844 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3845</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3846
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3847<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3848
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3849<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3850<pre>
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3851 &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3852 &lt;result&gt; = mul nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3853 &lt;result&gt; = mul nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3854 &lt;result&gt; = mul nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3855</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3856
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3857<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3858<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3859
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3860<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3861<p>The two arguments to the '<tt>mul</tt>' instruction must
3862 be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
3863 integer values. Both arguments must have identical types.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3864
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3865<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3866<p>The value produced is the integer product of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3867
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3868<p>If the result of the multiplication has unsigned overflow, the result
3869 returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
3870 width of the result.</p>
3871
3872<p>Because LLVM integers use a two's complement representation, and the result
3873 is the same width as the operands, this instruction returns the correct
3874 result for both signed and unsigned integers. If a full product
3875 (e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
3876 be sign-extended or zero-extended as appropriate to the width of the full
3877 product.</p>
3878
Dan Gohman902dfff2009-07-22 22:44:56 +0000[diff] [blame]3879<p><tt>nuw</tt> and <tt>nsw</tt> stand for &quot;No Unsigned Wrap&quot;
3880 and &quot;No Signed Wrap&quot;, respectively. If the <tt>nuw</tt> and/or
3881 <tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3882 is a <a href="#poisonvalues">poison value</a> if unsigned and/or signed overflow,
Dan Gohmanffc9a6b2010-04-22 23:14:21 +0000[diff] [blame]3883 respectively, occurs.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3884
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3885<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3886<pre>
3887 &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3888</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3889
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]3890</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3891
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]3892<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3893<h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3894 <a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3895</h4>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3896
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3897<div>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3898
3899<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3900<pre>
3901 &lt;result&gt; = fmul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3902</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3903
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3904<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3905<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3906
3907<h5>Arguments:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3908<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3909 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
3910 floating point values. Both arguments must have identical types.</p>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3911
3912<h5>Semantics:</h5>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3913<p>The value produced is the floating point product of the two operands.</p>
3914
3915<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3916<pre>
3917 &lt;result&gt; = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3918</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3919
Dan Gohmana5b96452009-06-04 22:49:04 +0000[diff] [blame]3920</div>
3921
3922<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3923<h4>
3924 <a name="i_udiv">'<tt>udiv</tt>' Instruction</a>
3925</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3926
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3927<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3928
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3929<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3930<pre>
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3931 &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
3932 &lt;result&gt; = udiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3933</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3934
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3935<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3936<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3937
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3938<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3939<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3940 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3941 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3942
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3943<h5>Semantics:</h5>
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3944<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3945
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3946<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3947 operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
3948
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3949<p>Division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3950
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3951<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3952 <tt>udiv</tt> is a <a href="#poisonvalues">poison value</a> if %op1 is not a
Chris Lattner35315d02011-02-06 21:44:57 +0000[diff] [blame]3953 multiple of %op2 (as such, "((a udiv exact b) mul b) == a").</p>
3954
3955
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3956<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3957<pre>
3958 &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3959</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3960
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3961</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3962
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3963<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]3964<h4>
3965 <a name="i_sdiv">'<tt>sdiv</tt>' Instruction</a>
3966</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3967
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]3968<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3969
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3970<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3971<pre>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3972 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Dan Gohman957b1312009-09-02 17:31:42 +0000[diff] [blame]3973 &lt;result&gt; = sdiv exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3974</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3975
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3976<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3977<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3978
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3979<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]3980<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3981 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3982 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]3983
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3984<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3985<p>The value produced is the signed integer quotient of the two operands rounded
3986 towards zero.</p>
3987
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3988<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3989 operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
3990
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]3991<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]3992 undefined behavior; this is a rare case, but can occur, for example, by doing
3993 a 32-bit division of -2147483648 by -1.</p>
3994
Dan Gohman71dfd782009-07-22 00:04:19 +0000[diff] [blame]3995<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]3996 <tt>sdiv</tt> is a <a href="#poisonvalues">poison value</a> if the result would
Dan Gohmane501ff72010-07-11 00:08:34 +0000[diff] [blame]3997 be rounded.</p>
Dan Gohmanb07de442009-07-20 22:41:19 +0000[diff] [blame]3998
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]3999<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4000<pre>
4001 &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4002</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4003
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4004</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4005
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4006<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4007<h4>
4008 <a name="i_fdiv">'<tt>fdiv</tt>' Instruction</a>
4009</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4010
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4011<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4012
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4013<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4014<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4015 &lt;result&gt; = fdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4016</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4017
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4018<h5>Overview:</h5>
4019<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4020
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4021<h5>Arguments:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4022<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4023 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4024 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4025
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4026<h5>Semantics:</h5>
Reid Spencer7e80b0b2006-10-26 06:15:43 +0000[diff] [blame]4027<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4028
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4029<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4030<pre>
4031 &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]4032</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4033
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4034</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4035
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4036<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4037<h4>
4038 <a name="i_urem">'<tt>urem</tt>' Instruction</a>
4039</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4040
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4041<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4042
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4043<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4044<pre>
4045 &lt;result&gt; = urem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4046</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4047
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4048<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4049<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
4050 division of its two arguments.</p>
4051
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4052<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4053<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4054 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4055 values. Both arguments must have identical types.</p>
4056
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4057<h5>Semantics:</h5>
4058<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4059 This instruction always performs an unsigned division to get the
4060 remainder.</p>
4061
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4062<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4063 distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
4064
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4065<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4066
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4067<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4068<pre>
4069 &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4070</pre>
4071
4072</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4073
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4074<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4075<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4076 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4077</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4078
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4079<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4080
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4081<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4082<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4083 &lt;result&gt; = srem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4084</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4085
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4086<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4087<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
4088 division of its two operands. This instruction can also take
4089 <a href="#t_vector">vector</a> versions of the values in which case the
4090 elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]4091
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4092<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4093<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4094 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4095 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4096
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4097<h5>Semantics:</h5>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4098<p>This instruction returns the <i>remainder</i> of a division (where the result
Duncan Sands2769c6e2011-03-07 09:12:24 +0000[diff] [blame]4099 is either zero or has the same sign as the dividend, <tt>op1</tt>), not the
4100 <i>modulo</i> operator (where the result is either zero or has the same sign
4101 as the divisor, <tt>op2</tt>) of a value.
4102 For more information about the difference,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4103 see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
4104 Math Forum</a>. For a table of how this is implemented in various languages,
4105 please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
4106 Wikipedia: modulo operation</a>.</p>
4107
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4108<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4109 distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
4110
Chris Lattner2f2427e2008-01-28 00:36:27 +0000[diff] [blame]4111<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4112 Overflow also leads to undefined behavior; this is a rare case, but can
4113 occur, for example, by taking the remainder of a 32-bit division of
4114 -2147483648 by -1. (The remainder doesn't actually overflow, but this rule
4115 lets srem be implemented using instructions that return both the result of
4116 the division and the remainder.)</p>
4117
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4118<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4119<pre>
4120 &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4121</pre>
4122
4123</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4124
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4125<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4126<h4>
4127 <a name="i_frem">'<tt>frem</tt>' Instruction</a>
4128</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4129
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4130<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4131
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4132<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4133<pre>
4134 &lt;result&gt; = frem &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4135</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4136
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4137<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4138<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
4139 its two operands.</p>
4140
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4141<h5>Arguments:</h5>
4142<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4143 <a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
4144 floating point values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4145
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4146<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4147<p>This instruction returns the <i>remainder</i> of a division. The remainder
4148 has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4149
Reid Spencer7eb55b32006-11-02 01:53:59 +0000[diff] [blame]4150<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4151<pre>
4152 &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]4153</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4154
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4155</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000[diff] [blame]4156
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4157</div>
4158
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4159<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4160<h3>
4161 <a name="bitwiseops">Bitwise Binary Operations</a>
4162</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4163
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4164<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4165
4166<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
4167 program. They are generally very efficient instructions and can commonly be
4168 strength reduced from other instructions. They require two operands of the
4169 same type, execute an operation on them, and produce a single value. The
4170 resulting value is the same type as its operands.</p>
4171
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4172<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4173<h4>
4174 <a name="i_shl">'<tt>shl</tt>' Instruction</a>
4175</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4176
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4177<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4178
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4179<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4180<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4181 &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4182 &lt;result&gt; = shl nuw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4183 &lt;result&gt; = shl nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4184 &lt;result&gt; = shl nuw nsw &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4185</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4186
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4187<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4188<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
4189 a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4190
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4191<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4192<p>Both arguments to the '<tt>shl</tt>' instruction must be the
4193 same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
4194 integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4195
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4196<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4197<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
4198 2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
4199 is (statically or dynamically) negative or equal to or larger than the number
4200 of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4201 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4202 shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4203
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4204<p>If the <tt>nuw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4205 <a href="#poisonvalues">poison value</a> if it shifts out any non-zero bits. If
Chris Lattnerf10dfdc2011-02-09 16:44:44 +0000[diff] [blame]4206 the <tt>nsw</tt> keyword is present, then the shift produces a
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4207 <a href="#poisonvalues">poison value</a> if it shifts out any bits that disagree
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4208 with the resultant sign bit. As such, NUW/NSW have the same semantics as
4209 they would if the shift were expressed as a mul instruction with the same
4210 nsw/nuw bits in (mul %op1, (shl 1, %op2)).</p>
4211
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4212<h5>Example:</h5>
4213<pre>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4214 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
4215 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
4216 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4217 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4218 &lt;result&gt; = shl &lt;2 x i32&gt; &lt; i32 1, i32 1&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 2, i32 4&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4219</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4220
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4221</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4222
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4223<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4224<h4>
4225 <a name="i_lshr">'<tt>lshr</tt>' Instruction</a>
4226</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4227
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4228<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4229
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4230<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4231<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4232 &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4233 &lt;result&gt; = lshr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4234</pre>
4235
4236<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4237<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
4238 operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4239
4240<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4241<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4242 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4243 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4244
4245<h5>Semantics:</h5>
4246<p>This instruction always performs a logical shift right operation. The most
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4247 significant bits of the result will be filled with zero bits after the shift.
4248 If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
4249 number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
4250 vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
4251 shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4252
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4253<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4254 <tt>lshr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4255 shifted out are non-zero.</p>
4256
4257
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4258<h5>Example:</h5>
4259<pre>
4260 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
4261 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
4262 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
4263 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4264 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4265 &lt;result&gt; = lshr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 2&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0x7FFFFFFF, i32 1&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4266</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4267
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4268</div>
4269
Reid Spencer2ab01932007-02-02 13:57:07 +0000[diff] [blame]4270<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4271<h4>
4272 <a name="i_ashr">'<tt>ashr</tt>' Instruction</a>
4273</h4>
4274
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4275<div>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4276
4277<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4278<pre>
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4279 &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4280 &lt;result&gt; = ashr exact &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4281</pre>
4282
4283<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4284<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
4285 operand shifted to the right a specified number of bits with sign
4286 extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4287
4288<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4289<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4290 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4291 type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4292
4293<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4294<p>This instruction always performs an arithmetic shift right operation, The
4295 most significant bits of the result will be filled with the sign bit
4296 of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
4297 larger than the number of bits in <tt>op1</tt>, the result is undefined. If
4298 the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
4299 the corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4300
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4301<p>If the <tt>exact</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]4302 <tt>ashr</tt> is a <a href="#poisonvalues">poison value</a> if any of the bits
Chris Lattnera676c0f2011-02-07 16:40:21 +0000[diff] [blame]4303 shifted out are non-zero.</p>
4304
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4305<h5>Example:</h5>
4306<pre>
4307 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
4308 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
4309 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
4310 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +0000[diff] [blame]4311 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +0000[diff] [blame]4312 &lt;result&gt; = ashr &lt;2 x i32&gt; &lt; i32 -2, i32 4&gt;, &lt; i32 1, i32 3&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 -1, i32 0&gt;</i>
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4313</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4314
Reid Spencer04e259b2007-01-31 21:39:12 +0000[diff] [blame]4315</div>
4316
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4317<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4318<h4>
4319 <a name="i_and">'<tt>and</tt>' Instruction</a>
4320</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4321
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4322<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4323
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4324<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4325<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]4326 &lt;result&gt; = and &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4327</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4328
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4329<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4330<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
4331 operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4332
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4333<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4334<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4335 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4336 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4337
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4338<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4339<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4340
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4341<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4342 <tbody>
4343 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4344 <th>In0</th>
4345 <th>In1</th>
4346 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4347 </tr>
4348 <tr>
4349 <td>0</td>
4350 <td>0</td>
4351 <td>0</td>
4352 </tr>
4353 <tr>
4354 <td>0</td>
4355 <td>1</td>
4356 <td>0</td>
4357 </tr>
4358 <tr>
4359 <td>1</td>
4360 <td>0</td>
4361 <td>0</td>
4362 </tr>
4363 <tr>
4364 <td>1</td>
4365 <td>1</td>
4366 <td>1</td>
4367 </tr>
4368 </tbody>
4369</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4370
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4371<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4372<pre>
4373 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4374 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
4375 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4376</pre>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4377</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4378<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4379<h4>
4380 <a name="i_or">'<tt>or</tt>' Instruction</a>
4381</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4382
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4383<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4384
4385<h5>Syntax:</h5>
4386<pre>
4387 &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
4388</pre>
4389
4390<h5>Overview:</h5>
4391<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
4392 two operands.</p>
4393
4394<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4395<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4396 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4397 values. Both arguments must have identical types.</p>
4398
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4399<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4400<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4401
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4402<table border="1" cellspacing="0" cellpadding="4">
4403 <tbody>
4404 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4405 <th>In0</th>
4406 <th>In1</th>
4407 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4408 </tr>
4409 <tr>
4410 <td>0</td>
4411 <td>0</td>
4412 <td>0</td>
4413 </tr>
4414 <tr>
4415 <td>0</td>
4416 <td>1</td>
4417 <td>1</td>
4418 </tr>
4419 <tr>
4420 <td>1</td>
4421 <td>0</td>
4422 <td>1</td>
4423 </tr>
4424 <tr>
4425 <td>1</td>
4426 <td>1</td>
4427 <td>1</td>
4428 </tr>
4429 </tbody>
4430</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4431
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4432<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4433<pre>
4434 &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4435 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
4436 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4437</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4438
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4439</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4440
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4441<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4442<h4>
4443 <a name="i_xor">'<tt>xor</tt>' Instruction</a>
4444</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4445
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4446<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4447
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4448<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4449<pre>
4450 &lt;result&gt; = xor &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4451</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4452
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4453<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4454<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
4455 its two operands. The <tt>xor</tt> is used to implement the "one's
4456 complement" operation, which is the "~" operator in C.</p>
4457
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4458<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4459<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4460 <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
4461 values. Both arguments must have identical types.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]4462
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4463<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4464<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4465
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4466<table border="1" cellspacing="0" cellpadding="4">
4467 <tbody>
4468 <tr>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4469 <th>In0</th>
4470 <th>In1</th>
4471 <th>Out</th>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4472 </tr>
4473 <tr>
4474 <td>0</td>
4475 <td>0</td>
4476 <td>0</td>
4477 </tr>
4478 <tr>
4479 <td>0</td>
4480 <td>1</td>
4481 <td>1</td>
4482 </tr>
4483 <tr>
4484 <td>1</td>
4485 <td>0</td>
4486 <td>1</td>
4487 </tr>
4488 <tr>
4489 <td>1</td>
4490 <td>1</td>
4491 <td>0</td>
4492 </tr>
4493 </tbody>
4494</table>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4495
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4496<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4497<pre>
4498 &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4499 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
4500 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
4501 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4502</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4503
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4504</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4505
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4506</div>
4507
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4508<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4509<h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4510 <a name="vectorops">Vector Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4511</h3>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4512
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4513<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4514
4515<p>LLVM supports several instructions to represent vector operations in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4516 target-independent manner. These instructions cover the element-access and
4517 vector-specific operations needed to process vectors effectively. While LLVM
4518 does directly support these vector operations, many sophisticated algorithms
4519 will want to use target-specific intrinsics to take full advantage of a
4520 specific target.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4521
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4522<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4523<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4524 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4525</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4526
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4527<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4528
4529<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4530<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4531 &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]4532</pre>
4533
4534<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4535<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
4536 from a vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4537
4538
4539<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4540<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
4541 of <a href="#t_vector">vector</a> type. The second operand is an index
4542 indicating the position from which to extract the element. The index may be
4543 a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4544
4545<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4546<p>The result is a scalar of the same type as the element type of
4547 <tt>val</tt>. Its value is the value at position <tt>idx</tt> of
4548 <tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4549 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4550
4551<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4552<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4553 &lt;result&gt; = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4554</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4555
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4556</div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4557
4558<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4559<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4560 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4561</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4562
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4563<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4564
4565<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4566<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +0000[diff] [blame]4567 &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]4568</pre>
4569
4570<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4571<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
4572 vector at a specified index.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4573
4574<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4575<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
4576 of <a href="#t_vector">vector</a> type. The second operand is a scalar value
4577 whose type must equal the element type of the first operand. The third
4578 operand is an index indicating the position at which to insert the value.
4579 The index may be a variable.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4580
4581<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4582<p>The result is a vector of the same type as <tt>val</tt>. Its element values
4583 are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
4584 value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
4585 results are undefined.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4586
4587<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4588<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4589 &lt;result&gt; = 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]4590</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4591
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4592</div>
4593
4594<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4595<h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4596 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4597</h4>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4598
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4599<div>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4600
4601<h5>Syntax:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4602<pre>
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4603 &lt;result&gt; = shufflevector &lt;n x &lt;ty&gt;&gt; &lt;v1&gt;, &lt;n x &lt;ty&gt;&gt; &lt;v2&gt;, &lt;m x i32&gt; &lt;mask&gt; <i>; yields &lt;m x &lt;ty&gt;&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4604</pre>
4605
4606<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4607<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
4608 from two input vectors, returning a vector with the same element type as the
4609 input and length that is the same as the shuffle mask.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4610
4611<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4612<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
4613 with types that match each other. The third argument is a shuffle mask whose
4614 element type is always 'i32'. The result of the instruction is a vector
4615 whose length is the same as the shuffle mask and whose element type is the
4616 same as the element type of the first two operands.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4617
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4618<p>The shuffle mask operand is required to be a constant vector with either
4619 constant integer or undef values.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4620
4621<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4622<p>The elements of the two input vectors are numbered from left to right across
4623 both of the vectors. The shuffle mask operand specifies, for each element of
4624 the result vector, which element of the two input vectors the result element
4625 gets. The element selector may be undef (meaning "don't care") and the
4626 second operand may be undef if performing a shuffle from only one vector.</p>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4627
4628<h5>Example:</h5>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4629<pre>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4630 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4631 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4632 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4633 &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.
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4634 &lt;result&gt; = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4635 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]4636 &lt;result&gt; = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Mon P Wang25f01062008-11-10 04:46:22 +0000[diff] [blame]4637 &lt;8 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 &gt; <i>; yields &lt;8 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4638</pre>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4639
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4640</div>
Tanya Lattnerb138bbe2006-04-14 19:24:33 +0000[diff] [blame]4641
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4642</div>
4643
Chris Lattnerce83bff2006-04-08 23:07:04 +0000[diff] [blame]4644<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4645<h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4646 <a name="aggregateops">Aggregate Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4647</h3>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4648
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4649<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4650
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4651<p>LLVM supports several instructions for working with
4652 <a href="#t_aggregate">aggregate</a> values.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4653
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4654<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4655<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4656 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4657</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4658
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4659<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4660
4661<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4662<pre>
4663 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
4664</pre>
4665
4666<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4667<p>The '<tt>extractvalue</tt>' instruction extracts the value of a member field
4668 from an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4669
4670<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4671<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4672 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4673 <a href="#t_array">array</a> type. The operands are constant indices to
4674 specify which value to extract in a similar manner as indices in a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4675 '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4676 <p>The major differences to <tt>getelementptr</tt> indexing are:</p>
4677 <ul>
4678 <li>Since the value being indexed is not a pointer, the first index is
4679 omitted and assumed to be zero.</li>
4680 <li>At least one index must be specified.</li>
4681 <li>Not only struct indices but also array indices must be in
4682 bounds.</li>
4683 </ul>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4684
4685<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4686<p>The result is the value at the position in the aggregate specified by the
4687 index operands.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4688
4689<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4690<pre>
Gabor Greif03ab4dc2009-10-28 13:14:50 +0000[diff] [blame]4691 &lt;result&gt; = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4692</pre>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4693
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4694</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4695
4696<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4697<h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4698 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4699</h4>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4700
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4701<div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4702
4703<h5>Syntax:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4704<pre>
Bill Wendlingf6a91cf2011-07-26 20:42:28 +0000[diff] [blame]4705 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;elt&gt;, &lt;idx&gt;{, &lt;idx&gt;}* <i>; yields &lt;aggregate type&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4706</pre>
4707
4708<h5>Overview:</h5>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4709<p>The '<tt>insertvalue</tt>' instruction inserts a value into a member field
4710 in an <a href="#t_aggregate">aggregate</a> value.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4711
4712<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4713<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]4714 of <a href="#t_struct">struct</a> or
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]4715 <a href="#t_array">array</a> type. The second operand is a first-class
4716 value to insert. The following operands are constant indices indicating
4717 the position at which to insert the value in a similar manner as indices in a
Frits van Bommel7cf63ac2010-12-05 20:54:38 +0000[diff] [blame]4718 '<tt><a href="#i_extractvalue">extractvalue</a></tt>' instruction. The
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4719 value to insert must have the same type as the value identified by the
4720 indices.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4721
4722<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4723<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
4724 that of <tt>val</tt> except that the value at the position specified by the
4725 indices is that of <tt>elt</tt>.</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4726
4727<h5>Example:</h5>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4728<pre>
Chris Lattnerc2e85402011-05-22 07:18:08 +0000[diff] [blame]4729 %agg1 = insertvalue {i32, float} undef, i32 1, 0 <i>; yields {i32 1, float undef}</i>
4730 %agg2 = insertvalue {i32, float} %agg1, float %val, 1 <i>; yields {i32 1, float %val}</i>
4731 %agg3 = insertvalue {i32, {float}} %agg1, float %val, 1, 0 <i>; yields {i32 1, float %val}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4732</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4733
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4734</div>
4735
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4736</div>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000[diff] [blame]4737
4738<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4739<h3>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]4740 <a name="memoryops">Memory Access and Addressing Operations</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4741</h3>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4742
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4743<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4744
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4745<p>A key design point of an SSA-based representation is how it represents
4746 memory. In LLVM, no memory locations are in SSA form, which makes things
Victor Hernandeza70c6df2009-10-26 23:44:29 +0000[diff] [blame]4747 very simple. This section describes how to read, write, and allocate
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4748 memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4749
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4750<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4751<h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4752 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4753</h4>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4754
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4755<div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4756
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4757<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4758<pre>
Dan Gohman2140a742010-05-28 01:14:11 +0000[diff] [blame]4759 &lt;result&gt; = alloca &lt;type&gt;[, &lt;ty&gt; &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4760</pre>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4761
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4762<h5>Overview:</h5>
Jeff Cohen5819f182007-04-22 01:17:39 +0000[diff] [blame]4763<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4764 currently executing function, to be automatically released when this function
4765 returns to its caller. The object is always allocated in the generic address
4766 space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4767
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4768<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4769<p>The '<tt>alloca</tt>' instruction
4770 allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt> bytes of memory on the
4771 runtime stack, returning a pointer of the appropriate type to the program.
4772 If "NumElements" is specified, it is the number of elements allocated,
4773 otherwise "NumElements" is defaulted to be one. If a constant alignment is
4774 specified, the value result of the allocation is guaranteed to be aligned to
4775 at least that boundary. If not specified, or if zero, the target can choose
4776 to align the allocation on any convenient boundary compatible with the
4777 type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4778
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4779<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4780
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4781<h5>Semantics:</h5>
Bill Wendling9ee6a312009-05-08 20:49:29 +0000[diff] [blame]4782<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4783 there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
4784 memory is automatically released when the function returns. The
4785 '<tt>alloca</tt>' instruction is commonly used to represent automatic
4786 variables that must have an address available. When the function returns
4787 (either with the <tt><a href="#i_ret">ret</a></tt>
Bill Wendling3f6a3a22012-02-06 21:57:33 +0000[diff] [blame]4788 or <tt><a href="#i_resume">resume</a></tt> instructions), the memory is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4789 reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4790
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4791<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4792<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +0000[diff] [blame]4793 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
4794 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
4795 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
4796 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4797</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4798
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4799</div>
Chris Lattner54611b42005-11-06 08:02:57 +0000[diff] [blame]4800
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]4801<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4802<h4>
4803 <a name="i_load">'<tt>load</tt>' Instruction</a>
4804</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4805
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4806<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4807
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4808<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4809<pre>
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]4810 &lt;result&gt; = load [volatile] &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;][, !invariant.load !&lt;index&gt;]
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]4811 &lt;result&gt; = load atomic [volatile] &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt;
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4812 !&lt;index&gt; = !{ i32 1 }
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4813</pre>
4814
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4815<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4816<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4817
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4818<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4819<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
4820 from which to load. The pointer must point to
4821 a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
4822 marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4823 number or order of execution of this <tt>load</tt> with other <a
4824 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4825
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4826<p>If the <code>load</code> is marked as <code>atomic</code>, it takes an extra
4827 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4828 argument. The <code>release</code> and <code>acq_rel</code> orderings are
4829 not valid on <code>load</code> instructions. Atomic loads produce <a
4830 href="#memorymodel">defined</a> results when they may see multiple atomic
4831 stores. The type of the pointee must be an integer type whose bit width
4832 is a power of two greater than or equal to eight and less than or equal
4833 to a target-specific size limit. <code>align</code> must be explicitly
4834 specified on atomic loads, and the load has undefined behavior if the
4835 alignment is not set to a value which is at least the size in bytes of
4836 the pointee. <code>!nontemporal</code> does not have any defined semantics
4837 for atomic loads.</p>
4838
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4839<p>The optional constant <tt>align</tt> argument specifies the alignment of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4840 operation (that is, the alignment of the memory address). A value of 0 or an
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4841 omitted <tt>align</tt> argument means that the operation has the preferential
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4842 alignment for the target. It is the responsibility of the code emitter to
4843 ensure that the alignment information is correct. Overestimating the
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4844 alignment results in undefined behavior. Underestimating the alignment may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4845 produce less efficient code. An alignment of 1 is always safe.</p>
4846
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4847<p>The optional <tt>!nontemporal</tt> metadata must reference a single
4848 metatadata name &lt;index&gt; corresponding to a metadata node with
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4849 one <tt>i32</tt> entry of value 1. The existence of
Bill Wendlingbc4024f2010-02-25 21:23:24 +0000[diff] [blame]4850 the <tt>!nontemporal</tt> metatadata on the instruction tells the optimizer
4851 and code generator that this load is not expected to be reused in the cache.
4852 The code generator may select special instructions to save cache bandwidth,
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4853 such as the <tt>MOVNT</tt> instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4854
Pete Cooper13e082d2012-02-10 18:13:54 +0000[diff] [blame]4855<p>The optional <tt>!invariant.load</tt> metadata must reference a single
4856 metatadata name &lt;index&gt; corresponding to a metadata node with no
4857 entries. The existence of the <tt>!invariant.load</tt> metatadata on the
4858 instruction tells the optimizer and code generator that this load address
4859 points to memory which does not change value during program execution.
4860 The optimizer may then move this load around, for example, by hoisting it
4861 out of loops using loop invariant code motion.</p>
4862
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4863<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4864<p>The location of memory pointed to is loaded. If the value being loaded is of
4865 scalar type then the number of bytes read does not exceed the minimum number
4866 of bytes needed to hold all bits of the type. For example, loading an
4867 <tt>i24</tt> reads at most three bytes. When loading a value of a type like
4868 <tt>i20</tt> with a size that is not an integral number of bytes, the result
4869 is undefined if the value was not originally written using a store of the
4870 same type.</p>
4871
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4872<h5>Examples:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4873<pre>
4874 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
4875 <a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]4876 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4877</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4878
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4879</div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4880
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4881<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]4882<h4>
4883 <a name="i_store">'<tt>store</tt>' Instruction</a>
4884</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4885
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]4886<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4887
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4888<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4889<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]4890 store [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;][, !nontemporal !&lt;index&gt;] <i>; yields {void}</i>
4891 store atomic [volatile] &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt; [singlethread] &lt;ordering&gt;, align &lt;alignment&gt; <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4892</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4893
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4894<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]4895<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4896
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4897<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4898<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
4899 and an address at which to store it. The type of the
4900 '<tt>&lt;pointer&gt;</tt>' operand must be a pointer to
4901 the <a href="#t_firstclass">first class</a> type of the
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]4902 '<tt>&lt;value&gt;</tt>' operand. If the <tt>store</tt> is marked as
4903 <tt>volatile</tt>, then the optimizer is not allowed to modify the number or
4904 order of execution of this <tt>store</tt> with other <a
4905 href="#volatile">volatile operations</a>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4906
Eli Friedman59b66882011-08-09 23:02:53 +0000[diff] [blame]4907<p>If the <code>store</code> is marked as <code>atomic</code>, it takes an extra
4908 <a href="#ordering">ordering</a> and optional <code>singlethread</code>
4909 argument. The <code>acquire</code> and <code>acq_rel</code> orderings aren't
4910 valid on <code>store</code> instructions. Atomic loads produce <a
4911 href="#memorymodel">defined</a> results when they may see multiple atomic
4912 stores. The type of the pointee must be an integer type whose bit width
4913 is a power of two greater than or equal to eight and less than or equal
4914 to a target-specific size limit. <code>align</code> must be explicitly
4915 specified on atomic stores, and the store has undefined behavior if the
4916 alignment is not set to a value which is at least the size in bytes of
4917 the pointee. <code>!nontemporal</code> does not have any defined semantics
4918 for atomic stores.</p>
4919
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4920<p>The optional constant "align" argument specifies the alignment of the
4921 operation (that is, the alignment of the memory address). A value of 0 or an
4922 omitted "align" argument means that the operation has the preferential
4923 alignment for the target. It is the responsibility of the code emitter to
4924 ensure that the alignment information is correct. Overestimating the
4925 alignment results in an undefined behavior. Underestimating the alignment may
4926 produce less efficient code. An alignment of 1 is always safe.</p>
4927
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4928<p>The optional !nontemporal metadata must reference a single metatadata
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]4929 name &lt;index&gt; corresponding to a metadata node with one i32 entry of
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4930 value 1. The existence of the !nontemporal metatadata on the
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4931 instruction tells the optimizer and code generator that this load is
4932 not expected to be reused in the cache. The code generator may
4933 select special instructions to save cache bandwidth, such as the
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]4934 MOVNT instruction on x86.</p>
David Greene9641d062010-02-16 20:50:18 +0000[diff] [blame]4935
4936
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]4937<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4938<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>' at the
4939 location specified by the '<tt>&lt;pointer&gt;</tt>' operand. If
4940 '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes written
4941 does not exceed the minimum number of bytes needed to hold all bits of the
4942 type. For example, storing an <tt>i24</tt> writes at most three bytes. When
4943 writing a value of a type like <tt>i20</tt> with a size that is not an
4944 integral number of bytes, it is unspecified what happens to the extra bits
4945 that do not belong to the type, but they will typically be overwritten.</p>
4946
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4947<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4948<pre>
4949 %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +0000[diff] [blame]4950 store i32 3, i32* %ptr <i>; yields {void}</i>
4951 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4952</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]4953
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]4954</div>
4955
Chris Lattner095735d2002-05-06 03:03:22 +0000[diff] [blame]4956<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4957<h4>
4958<a name="i_fence">'<tt>fence</tt>' Instruction</a>
4959</h4>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4960
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]4961<div>
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]4962
4963<h5>Syntax:</h5>
4964<pre>
4965 fence [singlethread] &lt;ordering&gt; <i>; yields {void}</i>
4966</pre>
4967
4968<h5>Overview:</h5>
4969<p>The '<tt>fence</tt>' instruction is used to introduce happens-before edges
4970between operations.</p>
4971
4972<h5>Arguments:</h5> <p>'<code>fence</code>' instructions take an <a
4973href="#ordering">ordering</a> argument which defines what
4974<i>synchronizes-with</i> edges they add. They can only be given
4975<code>acquire</code>, <code>release</code>, <code>acq_rel</code>, and
4976<code>seq_cst</code> orderings.</p>
4977
4978<h5>Semantics:</h5>
4979<p>A fence <var>A</var> which has (at least) <code>release</code> ordering
4980semantics <i>synchronizes with</i> a fence <var>B</var> with (at least)
4981<code>acquire</code> ordering semantics if and only if there exist atomic
4982operations <var>X</var> and <var>Y</var>, both operating on some atomic object
4983<var>M</var>, such that <var>A</var> is sequenced before <var>X</var>,
4984<var>X</var> modifies <var>M</var> (either directly or through some side effect
4985of a sequence headed by <var>X</var>), <var>Y</var> is sequenced before
4986<var>B</var>, and <var>Y</var> observes <var>M</var>. This provides a
4987<i>happens-before</i> dependency between <var>A</var> and <var>B</var>. Rather
4988than an explicit <code>fence</code>, one (but not both) of the atomic operations
4989<var>X</var> or <var>Y</var> might provide a <code>release</code> or
4990<code>acquire</code> (resp.) ordering constraint and still
4991<i>synchronize-with</i> the explicit <code>fence</code> and establish the
4992<i>happens-before</i> edge.</p>
4993
4994<p>A <code>fence</code> which has <code>seq_cst</code> ordering, in addition to
4995having both <code>acquire</code> and <code>release</code> semantics specified
4996above, participates in the global program order of other <code>seq_cst</code>
4997operations and/or fences.</p>
4998
4999<p>The optional "<a href="#singlethread"><code>singlethread</code></a>" argument
5000specifies that the fence only synchronizes with other fences in the same
5001thread. (This is useful for interacting with signal handlers.)</p>
5002
Eli Friedmanfee02c62011-07-25 23:16:38 +0000[diff] [blame]5003<h5>Example:</h5>
5004<pre>
5005 fence acquire <i>; yields {void}</i>
5006 fence singlethread seq_cst <i>; yields {void}</i>
5007</pre>
5008
5009</div>
5010
5011<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5012<h4>
5013<a name="i_cmpxchg">'<tt>cmpxchg</tt>' Instruction</a>
5014</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5015
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5016<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5017
5018<h5>Syntax:</h5>
5019<pre>
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5020 cmpxchg [volatile] &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;cmp&gt;, &lt;ty&gt; &lt;new&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5021</pre>
5022
5023<h5>Overview:</h5>
5024<p>The '<tt>cmpxchg</tt>' instruction is used to atomically modify memory.
5025It loads a value in memory and compares it to a given value. If they are
5026equal, it stores a new value into the memory.</p>
5027
5028<h5>Arguments:</h5>
5029<p>There are three arguments to the '<code>cmpxchg</code>' instruction: an
5030address to operate on, a value to compare to the value currently be at that
5031address, and a new value to place at that address if the compared values are
5032equal. The type of '<var>&lt;cmp&gt;</var>' must be an integer type whose
5033bit width is a power of two greater than or equal to eight and less than
5034or equal to a target-specific size limit. '<var>&lt;cmp&gt;</var>' and
5035'<var>&lt;new&gt;</var>' must have the same type, and the type of
5036'<var>&lt;pointer&gt;</var>' must be a pointer to that type. If the
5037<code>cmpxchg</code> is marked as <code>volatile</code>, then the
5038optimizer is not allowed to modify the number or order of execution
5039of this <code>cmpxchg</code> with other <a href="#volatile">volatile
5040operations</a>.</p>
5041
5042<!-- FIXME: Extend allowed types. -->
5043
5044<p>The <a href="#ordering"><var>ordering</var></a> argument specifies how this
5045<code>cmpxchg</code> synchronizes with other atomic operations.</p>
5046
5047<p>The optional "<code>singlethread</code>" argument declares that the
5048<code>cmpxchg</code> is only atomic with respect to code (usually signal
5049handlers) running in the same thread as the <code>cmpxchg</code>. Otherwise the
5050cmpxchg is atomic with respect to all other code in the system.</p>
5051
5052<p>The pointer passed into cmpxchg must have alignment greater than or equal to
5053the size in memory of the operand.
5054
5055<h5>Semantics:</h5>
5056<p>The contents of memory at the location specified by the
5057'<tt>&lt;pointer&gt;</tt>' operand is read and compared to
5058'<tt>&lt;cmp&gt;</tt>'; if the read value is the equal,
5059'<tt>&lt;new&gt;</tt>' is written. The original value at the location
5060is returned.
5061
5062<p>A successful <code>cmpxchg</code> is a read-modify-write instruction for the
5063purpose of identifying <a href="#release_sequence">release sequences</a>. A
5064failed <code>cmpxchg</code> is equivalent to an atomic load with an ordering
5065parameter determined by dropping any <code>release</code> part of the
5066<code>cmpxchg</code>'s ordering.</p>
5067
5068<!--
5069FIXME: Is compare_exchange_weak() necessary? (Consider after we've done
5070optimization work on ARM.)
5071
5072FIXME: Is a weaker ordering constraint on failure helpful in practice?
5073-->
5074
5075<h5>Example:</h5>
5076<pre>
5077entry:
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5078 %orig = atomic <a href="#i_load">load</a> i32* %ptr unordered <i>; yields {i32}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5079 <a href="#i_br">br</a> label %loop
5080
5081loop:
5082 %cmp = <a href="#i_phi">phi</a> i32 [ %orig, %entry ], [%old, %loop]
5083 %squared = <a href="#i_mul">mul</a> i32 %cmp, %cmp
Bill Wendling4517fe52011-12-09 22:41:40 +0000[diff] [blame]5084 %old = cmpxchg i32* %ptr, i32 %cmp, i32 %squared <i>; yields {i32}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5085 %success = <a href="#i_icmp">icmp</a> eq i32 %cmp, %old
5086 <a href="#i_br">br</a> i1 %success, label %done, label %loop
5087
5088done:
5089 ...
5090</pre>
5091
5092</div>
5093
5094<!-- _______________________________________________________________________ -->
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5095<h4>
5096<a name="i_atomicrmw">'<tt>atomicrmw</tt>' Instruction</a>
5097</h4>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5098
NAKAMURA Takumi0300d882011-08-12 06:17:17 +0000[diff] [blame]5099<div>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5100
5101<h5>Syntax:</h5>
5102<pre>
Eli Friedman02e737b2011-08-12 22:50:01 +0000[diff] [blame]5103 atomicrmw [volatile] &lt;operation&gt; &lt;ty&gt;* &lt;pointer&gt;, &lt;ty&gt; &lt;value&gt; [singlethread] &lt;ordering&gt; <i>; yields {ty}</i>
Eli Friedmanc9a551e2011-07-28 21:48:00 +0000[diff] [blame]5104</pre>
5105
5106<h5>Overview:</h5>
5107<p>The '<tt>atomicrmw</tt>' instruction is used to atomically modify memory.</p>
5108
5109<h5>Arguments:</h5>
5110<p>There are three arguments to the '<code>atomicrmw</code>' instruction: an
5111operation to apply, an address whose value to modify, an argument to the
5112operation. The operation must be one of the following keywords:</p>
5113<ul>
5114 <li>xchg</li>
5115 <li>add</li>
5116 <li>sub</li>
5117 <li>and</li>
5118 <li>nand</li>
5119 <li>or</li>
5120 <li>xor</li>
5121 <li>max</li>
5122 <li>min</li>
5123 <li>umax</li>
5124 <li>umin</li>
5125</ul>
5126
5127<p>The type of '<var>&lt;value&gt;</var>' must be an integer type whose
5128bit width is a power of two greater than or equal to eight and less than
5129or equal to a target-specific size limit. The type of the
5130'<code>&lt;pointer&gt;</code>' operand must be a pointer to that type.
5131If the <code>atomicrmw</code> is marked as <code>volatile</code>, then the
5132optimizer is not allowed to modify the number or order of execution of this
5133<code>atomicrmw</code> with other <a href="#volatile">volatile
5134 operations</a>.</p>
5135
5136<!-- FIXME: Extend allowed types. -->
5137
5138<h5>Semantics:</h5>
5139<p>The contents of memory at the location specified by the
5140'<tt>&lt;pointer&gt;</tt>' operand are atomically read, modified, and written
5141back. The original value at the location is returned. The modification is
5142specified by the <var>operation</var> argument:</p>
5143
5144<ul>
5145 <li>xchg: <code>*ptr = val</code></li>
5146 <li>add: <code>*ptr = *ptr + val</code></li>
5147 <li>sub: <code>*ptr = *ptr - val</code></li>
5148 <li>and: <code>*ptr = *ptr &amp; val</code></li>
5149 <li>nand: <code>*ptr = ~(*ptr &amp; val)</code></li>
5150 <li>or: <code>*ptr = *ptr | val</code></li>
5151 <li>xor: <code>*ptr = *ptr ^ val</code></li>
5152 <li>max: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using a signed comparison)</li>
5153 <li>min: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using a signed comparison)</li>
5154 <li>umax: <code>*ptr = *ptr &gt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5155 <li>umin: <code>*ptr = *ptr &lt; val ? *ptr : val</code> (using an unsigned comparison)</li>
5156</ul>
5157
5158<h5>Example:</h5>
5159<pre>
5160 %old = atomicrmw add i32* %ptr, i32 1 acquire <i>; yields {i32}</i>
5161</pre>
5162
5163</div>
5164
5165<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5166<h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5167 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5168</h4>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5169
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5170<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5171
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5172<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5173<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5174 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5175 &lt;result&gt; = getelementptr inbounds &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5176 &lt;result&gt; = getelementptr &lt;ptr vector&gt; ptrval, &lt;vector index type&gt; idx
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5177</pre>
5178
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5179<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5180<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5181 subelement of an <a href="#t_aggregate">aggregate</a> data structure.
5182 It performs address calculation only and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5183
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5184<h5>Arguments:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5185<p>The first argument is always a pointer or a vector of pointers,
5186 and forms the basis of the
Chris Lattnera40b9122009-07-29 06:44:13 +0000[diff] [blame]5187 calculation. The remaining arguments are indices that indicate which of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5188 elements of the aggregate object are indexed. The interpretation of each
5189 index is dependent on the type being indexed into. The first index always
5190 indexes the pointer value given as the first argument, the second index
5191 indexes a value of the type pointed to (not necessarily the value directly
5192 pointed to, since the first index can be non-zero), etc. The first type
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5193 indexed into must be a pointer value, subsequent types can be arrays,
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5194 vectors, and structs. Note that subsequent types being indexed into
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5195 can never be pointers, since that would require loading the pointer before
5196 continuing calculation.</p>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5197
5198<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner13ee7952010-08-28 04:09:24 +0000[diff] [blame]5199 When indexing into a (optionally packed) structure, only <tt>i32</tt>
Chris Lattner392be582010-02-12 20:49:41 +0000[diff] [blame]5200 integer <b>constants</b> are allowed. When indexing into an array, pointer
5201 or vector, integers of any width are allowed, and they are not required to be
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5202 constant. These integers are treated as signed values where relevant.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5203
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5204<p>For example, let's consider a C code fragment and how it gets compiled to
5205 LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5206
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5207<pre class="doc_code">
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5208struct RT {
5209 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5210 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5211 char C;
5212};
5213struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5214 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5215 double Y;
5216 struct RT Z;
5217};
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5218
Chris Lattnera446f1b2007-05-29 15:43:56 +0000[diff] [blame]5219int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5220 return &amp;s[1].Z.B[5][13];
5221}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5222</pre>
5223
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5224<p>The LLVM code generated by Clang is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5225
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]5226<pre class="doc_code">
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5227%struct.RT = <a href="#namedtypes">type</a> { i8, [10 x [20 x i32]], i8 }
5228%struct.ST = <a href="#namedtypes">type</a> { i32, double, %struct.RT }
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5229
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5230define i32* @foo(%struct.ST* %s) nounwind uwtable readnone optsize ssp {
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5231entry:
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5232 %arrayidx = getelementptr inbounds %struct.ST* %s, i64 1, i32 2, i32 1, i64 5, i64 13
5233 ret i32* %arrayidx
Bill Wendling3716c5d2007-05-29 09:04:49 +0000[diff] [blame]5234}
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5235</pre>
5236
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5237<h5>Semantics:</h5>
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5238<p>In the example above, the first index is indexing into the
5239 '<tt>%struct.ST*</tt>' type, which is a pointer, yielding a
5240 '<tt>%struct.ST</tt>' = '<tt>{ i32, double, %struct.RT }</tt>' type, a
5241 structure. The second index indexes into the third element of the structure,
5242 yielding a '<tt>%struct.RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]], i8 }</tt>'
5243 type, another structure. The third index indexes into the second element of
5244 the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an array. The
5245 two dimensions of the array are subscripted into, yielding an '<tt>i32</tt>'
5246 type. The '<tt>getelementptr</tt>' instruction returns a pointer to this
5247 element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5248
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5249<p>Note that it is perfectly legal to index partially through a structure,
5250 returning a pointer to an inner element. Because of this, the LLVM code for
5251 the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5252
Bill Wendling7ad1f362011-12-13 01:07:07 +0000[diff] [blame]5253<pre class="doc_code">
5254define i32* @foo(%struct.ST* %s) {
5255 %t1 = getelementptr %struct.ST* %s, i32 1 <i>; yields %struct.ST*:%t1</i>
5256 %t2 = getelementptr %struct.ST* %t1, i32 0, i32 2 <i>; yields %struct.RT*:%t2</i>
5257 %t3 = getelementptr %struct.RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
5258 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
5259 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
5260 ret i32* %t5
5261}
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5262</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +0000[diff] [blame]5263
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5264<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman9a2a0932011-12-06 03:18:47 +0000[diff] [blame]5265 <tt>getelementptr</tt> is a <a href="#poisonvalues">poison value</a> if the
Dan Gohman57255802010-04-23 15:23:32 +0000[diff] [blame]5266 base pointer is not an <i>in bounds</i> address of an allocated object,
5267 or if any of the addresses that would be formed by successive addition of
5268 the offsets implied by the indices to the base address with infinitely
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5269 precise signed arithmetic are not an <i>in bounds</i> address of that
5270 allocated object. The <i>in bounds</i> addresses for an allocated object
5271 are all the addresses that point into the object, plus the address one
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5272 byte past the end.
5273 In cases where the base is a vector of pointers the <tt>inbounds</tt> keyword
5274 applies to each of the computations element-wise. </p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5275
5276<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
Eli Friedmand8874dc2011-08-12 23:37:55 +0000[diff] [blame]5277 the base address with silently-wrapping two's complement arithmetic. If the
5278 offsets have a different width from the pointer, they are sign-extended or
5279 truncated to the width of the pointer. The result value of the
5280 <tt>getelementptr</tt> may be outside the object pointed to by the base
5281 pointer. The result value may not necessarily be used to access memory
5282 though, even if it happens to point into allocated storage. See the
5283 <a href="#pointeraliasing">Pointer Aliasing Rules</a> section for more
5284 information.</p>
Dan Gohman1639c392009-07-27 21:53:46 +0000[diff] [blame]5285
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5286<p>The getelementptr instruction is often confusing. For some more insight into
5287 how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Chris Lattner6ab66722006-08-15 00:45:58 +0000[diff] [blame]5288
Chris Lattner590645f2002-04-14 06:13:44 +0000[diff] [blame]5289<h5>Example:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5290<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5291 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5292 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
5293 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5294 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +0000[diff] [blame]5295 <i>; yields i8*:eptr</i>
5296 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta0c155e62009-04-25 07:27:44 +0000[diff] [blame]5297 <i>; yields i32*:iptr</i>
Sanjiv Gupta77abea02009-04-24 16:38:13 +0000[diff] [blame]5298 %iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5299</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5300
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5301<p>In cases where the pointer argument is a vector of pointers, only a
5302 single index may be used, and the number of vector elements has to be
5303 the same. For example: </p>
5304<pre class="doc_code">
5305 %A = getelementptr <4 x i8*> %ptrs, <4 x i64> %offsets,
5306</pre>
5307
Chris Lattner33fd7022004-04-05 01:30:49 +0000[diff] [blame]5308</div>
Reid Spencer443460a2006-11-09 21:15:49 +0000[diff] [blame]5309
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5310</div>
5311
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]5312<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5313<h3>
5314 <a name="convertops">Conversion Operations</a>
5315</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5316
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5317<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5318
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5319<p>The instructions in this category are the conversion instructions (casting)
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5320 which all take a single operand and a type. They perform various bit
5321 conversions on the operand.</p>
5322
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5323<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5324<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5325 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5326</h4>
5327
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5328<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5329
5330<h5>Syntax:</h5>
5331<pre>
5332 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5333</pre>
5334
5335<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5336<p>The '<tt>trunc</tt>' instruction truncates its operand to the
5337 type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5338
5339<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5340<p>The '<tt>trunc</tt>' instruction takes a value to trunc, and a type to trunc it to.
5341 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5342 of the same number of integers.
5343 The bit size of the <tt>value</tt> must be larger than
5344 the bit size of the destination type, <tt>ty2</tt>.
5345 Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5346
5347<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5348<p>The '<tt>trunc</tt>' instruction truncates the high order bits
5349 in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
5350 source size must be larger than the destination size, <tt>trunc</tt> cannot
5351 be a <i>no-op cast</i>. It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5352
5353<h5>Example:</h5>
5354<pre>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5355 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
5356 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
5357 %Z = trunc i32 122 to i1 <i>; yields i1:false</i>
5358 %W = trunc &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i8&gt; <i>; yields &lt;i8 8, i8 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5359</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5360
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5361</div>
5362
5363<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5364<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5365 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5366</h4>
5367
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5368<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5369
5370<h5>Syntax:</h5>
5371<pre>
5372 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5373</pre>
5374
5375<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5376<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5377 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5378
5379
5380<h5>Arguments:</h5>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5381<p>The '<tt>zext</tt>' instruction takes a value to cast, and a type to cast it to.
5382 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5383 of the same number of integers.
5384 The bit size of the <tt>value</tt> must be smaller than
5385 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5386 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5387
5388<h5>Semantics:</h5>
5389<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5390 bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5391
Reid Spencer07c9c682007-01-12 15:46:11 +0000[diff] [blame]5392<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]5393
5394<h5>Example:</h5>
5395<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5396 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5397 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Nadav Rotem25f2ac92011-02-20 12:37:50 +0000[diff] [blame]5398 %Z = zext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5399</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5400
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5401</div>
5402
5403<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5404<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5405 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5406</h4>
5407
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5408<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5409
5410<h5>Syntax:</h5>
5411<pre>
5412 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5413</pre>
5414
5415<h5>Overview:</h5>
5416<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
5417
5418<h5>Arguments:</h5>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5419<p>The '<tt>sext</tt>' instruction takes a value to cast, and a type to cast it to.
5420 Both types must be of <a href="#t_integer">integer</a> types, or vectors
5421 of the same number of integers.
5422 The bit size of the <tt>value</tt> must be smaller than
5423 the bit size of the destination type,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5424 <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5425
5426<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5427<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
5428 bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
5429 of the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5430
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5431<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]5432
5433<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5434<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5435 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5436 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Nadav Rotem502f1b92011-02-24 21:01:34 +0000[diff] [blame]5437 %Z = sext &lt;2 x i16&gt; &lt;i16 8, i16 7&gt; to &lt;2 x i32&gt; <i>; yields &lt;i32 8, i32 7&gt;</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5438</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5439
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5440</div>
5441
5442<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5443<h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5444 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5445</h4>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5446
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5447<div>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5448
5449<h5>Syntax:</h5>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5450<pre>
5451 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5452</pre>
5453
5454<h5>Overview:</h5>
5455<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5456 <tt>ty2</tt>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5457
5458<h5>Arguments:</h5>
5459<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5460 point</a> value to cast and a <a href="#t_floating">floating point</a> type
5461 to cast it to. The size of <tt>value</tt> must be larger than the size of
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5462 <tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5463 <i>no-op cast</i>.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5464
5465<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5466<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5467 <a href="#t_floating">floating point</a> type to a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5468 <a href="#t_floating">floating point</a> type. If the value cannot fit
5469 within the destination type, <tt>ty2</tt>, then the results are
5470 undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5471
5472<h5>Example:</h5>
5473<pre>
5474 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
5475 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
5476</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5477
Reid Spencer2e2740d2006-11-09 21:48:10 +0000[diff] [blame]5478</div>
5479
5480<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5481<h4>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5482 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5483</h4>
5484
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5485<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5486
5487<h5>Syntax:</h5>
5488<pre>
5489 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5490</pre>
5491
5492<h5>Overview:</h5>
5493<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5494 floating point value.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5495
5496<h5>Arguments:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5497<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5498 <a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
5499 a <a href="#t_floating">floating point</a> type to cast it to. The source
5500 type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5501
5502<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5503<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5504 <a href="#t_floating">floating point</a> type to a larger
5505 <a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
5506 used to make a <i>no-op cast</i> because it always changes bits. Use
5507 <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]5508
5509<h5>Example:</h5>
5510<pre>
Nick Lewycky9feca672011-03-31 18:20:19 +0000[diff] [blame]5511 %X = fpext float 3.125 to double <i>; yields double:3.125000e+00</i>
5512 %Y = fpext double %X to fp128 <i>; yields fp128:0xL00000000000000004000900000000000</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5513</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5514
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5515</div>
5516
5517<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5518<h4>
Reid Spencer2eadb532007-01-21 00:29:26 +0000[diff] [blame]5519 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5520</h4>
5521
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5522<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5523
5524<h5>Syntax:</h5>
5525<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5526 &lt;result&gt; = fptoui &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5527</pre>
5528
5529<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5530<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5531 unsigned integer equivalent of type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5532
5533<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5534<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
5535 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5536 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5537 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5538 vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5539
5540<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5541<p>The '<tt>fptoui</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5542 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5543 towards zero) unsigned integer value. If the value cannot fit
5544 in <tt>ty2</tt>, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5545
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5546<h5>Example:</h5>
5547<pre>
Reid Spencer753163d2007-07-31 14:40:14 +0000[diff] [blame]5548 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5549 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5550 %Z = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5551</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5552
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5553</div>
5554
5555<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5556<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5557 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5558</h4>
5559
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5560<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5561
5562<h5>Syntax:</h5>
5563<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5564 &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]5565</pre>
5566
5567<h5>Overview:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5568<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5569 <a href="#t_floating">floating point</a> <tt>value</tt> to
5570 type <tt>ty2</tt>.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5571
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5572<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5573<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
5574 scalar or vector <a href="#t_floating">floating point</a> value, and a type
5575 to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
5576 type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
5577 vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5578
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]5579<h5>Semantics:</h5>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5580<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5581 <a href="#t_floating">floating point</a> operand into the nearest (rounding
5582 towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
5583 the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5584
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5585<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5586<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]5587 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +0000[diff] [blame]5588 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5589 %Z = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5590</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5591
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5592</div>
5593
5594<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5595<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5596 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5597</h4>
5598
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5599<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5600
5601<h5>Syntax:</h5>
5602<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5603 &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]5604</pre>
5605
5606<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5607<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5608 integer and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5609
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5610<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5611<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5612 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5613 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5614 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5615 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5616
5617<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5618<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5619 integer quantity and converts it to the corresponding floating point
5620 value. If the value cannot fit in the floating point value, the results are
5621 undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5622
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5623<h5>Example:</h5>
5624<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5625 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5626 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5627</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5628
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5629</div>
5630
5631<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5632<h4>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5633 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5634</h4>
5635
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5636<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5637
5638<h5>Syntax:</h5>
5639<pre>
Reid Spencer51b07252006-11-09 23:03:26 +0000[diff] [blame]5640 &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]5641</pre>
5642
5643<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5644<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
5645 and converts that value to the <tt>ty2</tt> type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5646
5647<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +0000[diff] [blame]5648<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5649 scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
5650 it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
5651 type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
5652 floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5653
5654<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5655<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
5656 quantity and converts it to the corresponding floating point value. If the
5657 value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5658
5659<h5>Example:</h5>
5660<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5661 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]5662 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5663</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5664
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5665</div>
5666
5667<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5668<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5669 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5670</h4>
5671
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5672<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5673
5674<h5>Syntax:</h5>
5675<pre>
5676 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5677</pre>
5678
5679<h5>Overview:</h5>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5680<p>The '<tt>ptrtoint</tt>' instruction converts the pointer or a vector of
5681 pointers <tt>value</tt> to
5682 the integer (or vector of integers) type <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5683
5684<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5685<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5686 must be a a value of type <a href="#t_pointer">pointer</a> or a vector of
5687 pointers, and a type to cast it to
5688 <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> or a vector
5689 of integers type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5690
5691<h5>Semantics:</h5>
5692<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5693 <tt>ty2</tt> by interpreting the pointer value as an integer and either
5694 truncating or zero extending that value to the size of the integer type. If
5695 <tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
5696 <tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
5697 are the same size, then nothing is done (<i>no-op cast</i>) other than a type
5698 change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5699
5700<h5>Example:</h5>
5701<pre>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5702 %X = ptrtoint i32* %P to i8 <i>; yields truncation on 32-bit architecture</i>
5703 %Y = ptrtoint i32* %P to i64 <i>; yields zero extension on 32-bit architecture</i>
5704 %Z = ptrtoint &lt;4 x i32*&gt; %P to &lt;4 x i64&gt;<i>; yields vector zero extension for a vector of addresses on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5705</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5706
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5707</div>
5708
5709<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5710<h4>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5711 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5712</h4>
5713
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5714<div>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5715
5716<h5>Syntax:</h5>
5717<pre>
5718 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
5719</pre>
5720
5721<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5722<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
5723 pointer type, <tt>ty2</tt>.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5724
5725<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +0000[diff] [blame]5726<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5727 value to cast, and a type to cast it to, which must be a
5728 <a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5729
5730<h5>Semantics:</h5>
5731<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5732 <tt>ty2</tt> by applying either a zero extension or a truncation depending on
5733 the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
5734 size of a pointer then a truncation is done. If <tt>value</tt> is smaller
5735 than the size of a pointer then a zero extension is done. If they are the
5736 same size, nothing is done (<i>no-op cast</i>).</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5737
5738<h5>Example:</h5>
5739<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5740 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
Gabor Greiff50fd572009-10-28 09:21:30 +0000[diff] [blame]5741 %Y = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
5742 %Z = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5743 %Z = inttoptr &lt;4 x i32&gt; %G to &lt;4 x i8*&gt;<i>; yields truncation of vector G to four pointers</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5744</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5745
Reid Spencerb7344ff2006-11-11 21:00:47 +0000[diff] [blame]5746</div>
5747
5748<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5749<h4>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5750 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5751</h4>
5752
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5753<div>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5754
5755<h5>Syntax:</h5>
5756<pre>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5757 &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]5758</pre>
5759
5760<h5>Overview:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5761<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5762 <tt>ty2</tt> without changing any bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5763
5764<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5765<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
5766 non-aggregate first class value, and a type to cast it to, which must also be
5767 a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
5768 of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
5769 identical. If the source type is a pointer, the destination type must also be
5770 a pointer. This instruction supports bitwise conversion of vectors to
5771 integers and to vectors of other types (as long as they have the same
5772 size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5773
5774<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +0000[diff] [blame]5775<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5776 <tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
5777 this conversion. The conversion is done as if the <tt>value</tt> had been
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5778 stored to memory and read back as type <tt>ty2</tt>.
5779 Pointer (or vector of pointers) types may only be converted to other pointer
5780 (or vector of pointers) types with this instruction. To convert
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5781 pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
5782 <a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000[diff] [blame]5783
5784<h5>Example:</h5>
5785<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5786 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5787 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5788 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
5789 %Z = bitcast &lt;2 x i32*&gt; %V to &lt;2 x i64*&gt; <i>; yields &lt;2 x i64*&gt;</i>
Chris Lattner70de6632001-07-09 00:26:23 +0000[diff] [blame]5790</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5791
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]5792</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]5793
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5794</div>
5795
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]5796<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5797<h3>
5798 <a name="otherops">Other Operations</a>
5799</h3>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5800
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5801<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5802
5803<p>The instructions in this category are the "miscellaneous" instructions, which
5804 defy better classification.</p>
5805
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5806<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5807<h4>
5808 <a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
5809</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5810
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5811<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5812
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5813<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5814<pre>
5815 &lt;result&gt; = icmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5816</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5817
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5818<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5819<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
Nadav Rotem3924cb02011-12-05 06:29:09 +0000[diff] [blame]5820 boolean values based on comparison of its two integer, integer vector,
5821 pointer, or pointer vector operands.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5822
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5823<h5>Arguments:</h5>
5824<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5825 the condition code indicating the kind of comparison to perform. It is not a
5826 value, just a keyword. The possible condition code are:</p>
5827
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5828<ol>
5829 <li><tt>eq</tt>: equal</li>
5830 <li><tt>ne</tt>: not equal </li>
5831 <li><tt>ugt</tt>: unsigned greater than</li>
5832 <li><tt>uge</tt>: unsigned greater or equal</li>
5833 <li><tt>ult</tt>: unsigned less than</li>
5834 <li><tt>ule</tt>: unsigned less or equal</li>
5835 <li><tt>sgt</tt>: signed greater than</li>
5836 <li><tt>sge</tt>: signed greater or equal</li>
5837 <li><tt>slt</tt>: signed less than</li>
5838 <li><tt>sle</tt>: signed less or equal</li>
5839</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5840
Chris Lattnerc0f423a2007-01-15 01:54:13 +0000[diff] [blame]5841<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5842 <a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
5843 typed. They must also be identical types.</p>
5844
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5845<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5846<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
5847 condition code given as <tt>cond</tt>. The comparison performed always yields
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5848 either an <a href="#t_integer"><tt>i1</tt></a> or vector of <tt>i1</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5849 result, as follows:</p>
5850
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5851<ol>
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5852 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5853 <tt>false</tt> otherwise. No sign interpretation is necessary or
5854 performed.</li>
5855
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5856 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5857 <tt>false</tt> otherwise. No sign interpretation is necessary or
5858 performed.</li>
5859
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5860 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5861 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5862
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5863 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5864 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5865 to <tt>op2</tt>.</li>
5866
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5867 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5868 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5869
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5870 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5871 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5872
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5873 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5874 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5875
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5876 <li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5877 <tt>true</tt> if <tt>op1</tt> is greater than or equal
5878 to <tt>op2</tt>.</li>
5879
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5880 <li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5881 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
5882
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5883 <li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5884 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5885</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5886
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5887<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5888 values are compared as if they were integers.</p>
5889
5890<p>If the operands are integer vectors, then they are compared element by
5891 element. The result is an <tt>i1</tt> vector with the same number of elements
5892 as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5893
5894<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5895<pre>
5896 &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]5897 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
5898 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
5899 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
5900 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
5901 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5902</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]5903
5904<p>Note that the code generator does not yet support vector types with
5905 the <tt>icmp</tt> instruction.</p>
5906
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5907</div>
5908
5909<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]5910<h4>
5911 <a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
5912</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5913
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]5914<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5915
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5916<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5917<pre>
5918 &lt;result&gt; = fcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {i1} or {&lt;N x i1&gt;}:result</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5919</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5920
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5921<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5922<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
5923 values based on comparison of its operands.</p>
5924
5925<p>If the operands are floating point scalars, then the result type is a boolean
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5926(<a href="#t_integer"><tt>i1</tt></a>).</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5927
5928<p>If the operands are floating point vectors, then the result type is a vector
5929 of boolean with the same number of elements as the operands being
5930 compared.</p>
5931
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5932<h5>Arguments:</h5>
5933<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5934 the condition code indicating the kind of comparison to perform. It is not a
5935 value, just a keyword. The possible condition code are:</p>
5936
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5937<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5938 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5939 <li><tt>oeq</tt>: ordered and equal</li>
5940 <li><tt>ogt</tt>: ordered and greater than </li>
5941 <li><tt>oge</tt>: ordered and greater than or equal</li>
5942 <li><tt>olt</tt>: ordered and less than </li>
5943 <li><tt>ole</tt>: ordered and less than or equal</li>
5944 <li><tt>one</tt>: ordered and not equal</li>
5945 <li><tt>ord</tt>: ordered (no nans)</li>
5946 <li><tt>ueq</tt>: unordered or equal</li>
5947 <li><tt>ugt</tt>: unordered or greater than </li>
5948 <li><tt>uge</tt>: unordered or greater than or equal</li>
5949 <li><tt>ult</tt>: unordered or less than </li>
5950 <li><tt>ule</tt>: unordered or less than or equal</li>
5951 <li><tt>une</tt>: unordered or not equal</li>
5952 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5953 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5954</ol>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5955
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]5956<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5957 <i>unordered</i> means that either operand may be a QNAN.</p>
5958
5959<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
5960 a <a href="#t_floating">floating point</a> type or
5961 a <a href="#t_vector">vector</a> of floating point type. They must have
5962 identical types.</p>
5963
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5964<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +0000[diff] [blame]5965<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5966 according to the condition code given as <tt>cond</tt>. If the operands are
5967 vectors, then the vectors are compared element by element. Each comparison
Nick Lewycky84a1eeb2009-09-27 00:45:11 +0000[diff] [blame]5968 performed always yields an <a href="#t_integer">i1</a> result, as
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5969 follows:</p>
5970
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]5971<ol>
5972 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5973
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5974 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5975 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5976
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5977 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]5978 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5979
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5980 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5981 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
5982
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5983 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5984 <tt>op1</tt> is less than <tt>op2</tt>.</li>
5985
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5986 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5987 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
5988
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5989 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5990 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
5991
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]5992 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5993
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5994 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5995 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
5996
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]5997 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]5998 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
5999
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6000 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6001 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
6002
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6003 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6004 <tt>op1</tt> is less than <tt>op2</tt>.</li>
6005
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6006 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6007 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
6008
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6009 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6010 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
6011
Reid Spencerf69acf32006-11-19 03:00:14 +0000[diff] [blame]6012 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6013
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6014 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
6015</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6016
6017<h5>Example:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6018<pre>
6019 &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]6020 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
6021 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
6022 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6023</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6024
6025<p>Note that the code generator does not yet support vector types with
6026 the <tt>fcmp</tt> instruction.</p>
6027
Reid Spencerc828a0e2006-11-18 21:50:54 +0000[diff] [blame]6028</div>
6029
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6030<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6031<h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6032 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6033</h4>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6034
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6035<div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6036
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6037<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6038<pre>
6039 &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...
6040</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6041
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6042<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6043<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in the
6044 SSA graph representing the function.</p>
6045
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6046<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6047<p>The type of the incoming values is specified with the first type field. After
6048 this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
6049 one pair for each predecessor basic block of the current block. Only values
6050 of <a href="#t_firstclass">first class</a> type may be used as the value
6051 arguments to the PHI node. Only labels may be used as the label
6052 arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6053
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6054<p>There must be no non-phi instructions between the start of a basic block and
6055 the PHI instructions: i.e. PHI instructions must be first in a basic
6056 block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6057
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6058<p>For the purposes of the SSA form, the use of each incoming value is deemed to
6059 occur on the edge from the corresponding predecessor block to the current
6060 block (but after any definition of an '<tt>invoke</tt>' instruction's return
6061 value on the same edge).</p>
Jay Foad1a4eea52009-06-03 10:20:10 +0000[diff] [blame]6062
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6063<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6064<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6065 specified by the pair corresponding to the predecessor basic block that
6066 executed just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6067
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6068<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +0000[diff] [blame]6069<pre>
6070Loop: ; Infinite loop that counts from 0 on up...
6071 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
6072 %nextindvar = add i32 %indvar, 1
6073 br label %Loop
6074</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6075
Reid Spencer97c5fa42006-11-08 01:18:52 +0000[diff] [blame]6076</div>
6077
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6078<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6079<h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6080 <a name="i_select">'<tt>select</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6081</h4>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6082
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6083<div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6084
6085<h5>Syntax:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6086<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +0000[diff] [blame]6087 &lt;result&gt; = select <i>selty</i> &lt;cond&gt;, &lt;ty&gt; &lt;val1&gt;, &lt;ty&gt; &lt;val2&gt; <i>; yields ty</i>
6088
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6089 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6090</pre>
6091
6092<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6093<p>The '<tt>select</tt>' instruction is used to choose one value based on a
6094 condition, without branching.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6095
6096
6097<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6098<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
6099 values indicating the condition, and two values of the
6100 same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
6101 vectors and the condition is a scalar, then entire vectors are selected, not
6102 individual elements.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6103
6104<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6105<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
6106 first value argument; otherwise, it returns the second value argument.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6107
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6108<p>If the condition is a vector of i1, then the value arguments must be vectors
6109 of the same size, and the selection is done element by element.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6110
6111<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6112<pre>
Reid Spencer36a15422007-01-12 03:35:51 +0000[diff] [blame]6113 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6114</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +0000[diff] [blame]6115
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000[diff] [blame]6116</div>
6117
Robert Bocchinof72fdfe2006-01-15 20:48:27 +0000[diff] [blame]6118<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6119<h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6120 <a name="i_call">'<tt>call</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6121</h4>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6122
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6123<div>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6124
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6125<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6126<pre>
Devang Patel02256232008-10-07 17:48:33 +0000[diff] [blame]6127 &lt;result&gt; = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] &lt;ty&gt; [&lt;fnty&gt;*] &lt;fnptrval&gt;(&lt;function args&gt;) [<a href="#fnattrs">fn attrs</a>]
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6128</pre>
6129
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6130<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6131<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6132
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6133<h5>Arguments:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6134<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6135
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6136<ol>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6137 <li>The optional "tail" marker indicates that the callee function does not
6138 access any allocas or varargs in the caller. Note that calls may be
6139 marked "tail" even if they do not occur before
6140 a <a href="#i_ret"><tt>ret</tt></a> instruction. If the "tail" marker is
6141 present, the function call is eligible for tail call optimization,
6142 but <a href="CodeGenerator.html#tailcallopt">might not in fact be
Evan Cheng59676492010-03-08 21:05:02 +0000[diff] [blame]6143 optimized into a jump</a>. The code generator may optimize calls marked
6144 "tail" with either 1) automatic <a href="CodeGenerator.html#sibcallopt">
6145 sibling call optimization</a> when the caller and callee have
6146 matching signatures, or 2) forced tail call optimization when the
6147 following extra requirements are met:
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6148 <ul>
6149 <li>Caller and callee both have the calling
6150 convention <tt>fastcc</tt>.</li>
6151 <li>The call is in tail position (ret immediately follows call and ret
6152 uses value of call or is void).</li>
6153 <li>Option <tt>-tailcallopt</tt> is enabled,
Dan Gohman6232f732010-03-02 01:08:11 +0000[diff] [blame]6154 or <code>llvm::GuaranteedTailCallOpt</code> is <code>true</code>.</li>
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6155 <li><a href="CodeGenerator.html#tailcallopt">Platform specific
6156 constraints are met.</a></li>
6157 </ul>
6158 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6159
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6160 <li>The optional "cconv" marker indicates which <a href="#callingconv">calling
6161 convention</a> the call should use. If none is specified, the call
Jeffrey Yasskinb8677462010-01-09 19:44:16 +0000[diff] [blame]6162 defaults to using C calling conventions. The calling convention of the
6163 call must match the calling convention of the target function, or else the
6164 behavior is undefined.</li>
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6165
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6166 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
6167 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
6168 '<tt>inreg</tt>' attributes are valid here.</li>
6169
6170 <li>'<tt>ty</tt>': the type of the call instruction itself which is also the
6171 type of the return value. Functions that return no value are marked
6172 <tt><a href="#t_void">void</a></tt>.</li>
6173
6174 <li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
6175 being invoked. The argument types must match the types implied by this
6176 signature. This type can be omitted if the function is not varargs and if
6177 the function type does not return a pointer to a function.</li>
6178
6179 <li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
6180 be invoked. In most cases, this is a direct function invocation, but
6181 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
6182 to function value.</li>
6183
6184 <li>'<tt>function args</tt>': argument list whose types match the function
Chris Lattner47f2a832010-03-02 06:36:51 +0000[diff] [blame]6185 signature argument types and parameter attributes. All arguments must be
6186 of <a href="#t_firstclass">first class</a> type. If the function
6187 signature indicates the function accepts a variable number of arguments,
6188 the extra arguments can be specified.</li>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6189
6190 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
6191 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
6192 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattnera8292f32002-05-06 22:08:29 +0000[diff] [blame]6193</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6194
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6195<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6196<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
6197 a specified function, with its incoming arguments bound to the specified
6198 values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
6199 function, control flow continues with the instruction after the function
6200 call, and the return value of the function is bound to the result
6201 argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6202
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]6203<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6204<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +0000[diff] [blame]6205 %retval = call i32 @test(i32 %argc)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6206 call i32 (i8*, ...)* @printf(i8* %msg, i32 12, i8 42) <i>; yields i32</i>
Chris Lattnerfb7c88d2008-03-21 17:24:17 +0000[diff] [blame]6207 %X = tail call i32 @foo() <i>; yields i32</i>
6208 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
6209 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +0000[diff] [blame]6210
6211 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +0000[diff] [blame]6212 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +0000[diff] [blame]6213 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
6214 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +0000[diff] [blame]6215 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +0000[diff] [blame]6216 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +0000[diff] [blame]6217</pre>
6218
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6219<p>llvm treats calls to some functions with names and arguments that match the
Dale Johannesen722212d2009-09-25 17:04:42 +0000[diff] [blame]6220standard C99 library as being the C99 library functions, and may perform
6221optimizations or generate code for them under that assumption. This is
6222something we'd like to change in the future to provide better support for
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6223freestanding environments and non-C-based languages.</p>
Dale Johannesen68f971b2009-09-24 18:38:21 +0000[diff] [blame]6224
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6225</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6226
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6227<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6228<h4>
Chris Lattner33337472006-01-13 23:26:01 +0000[diff] [blame]6229 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6230</h4>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6231
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6232<div>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6233
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6234<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6235<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6236 &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]6237</pre>
6238
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6239<h5>Overview:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6240<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6241 the "variable argument" area of a function call. It is used to implement the
6242 <tt>va_arg</tt> macro in C.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6243
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6244<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6245<p>This instruction takes a <tt>va_list*</tt> value and the type of the
6246 argument. It returns a value of the specified argument type and increments
6247 the <tt>va_list</tt> to point to the next argument. The actual type
6248 of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6249
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6250<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6251<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
6252 from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
6253 to the next argument. For more information, see the variable argument
6254 handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6255
6256<p>It is legal for this instruction to be called in a function which does not
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6257 take a variable number of arguments, for example, the <tt>vfprintf</tt>
6258 function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6259
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6260<p><tt>va_arg</tt> is an LLVM instruction instead of
6261 an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
6262 argument.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6263
Chris Lattner26ca62e2003-10-18 05:51:36 +0000[diff] [blame]6264<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +0000[diff] [blame]6265<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
6266
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6267<p>Note that the code generator does not yet fully support va_arg on many
6268 targets. Also, it does not currently support va_arg with aggregate types on
6269 any target.</p>
Dan Gohman3065b612009-01-12 23:12:39 +0000[diff] [blame]6270
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6271</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6272
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6273<!-- _______________________________________________________________________ -->
6274<h4>
6275 <a name="i_landingpad">'<tt>landingpad</tt>' Instruction</a>
6276</h4>
6277
6278<div>
6279
6280<h5>Syntax:</h5>
6281<pre>
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6282 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; &lt;clause&gt;+
6283 &lt;resultval&gt; = landingpad &lt;resultty&gt; personality &lt;type&gt; &lt;pers_fn&gt; cleanup &lt;clause&gt;*
Bill Wendling49bfb122011-08-08 08:06:05 +0000[diff] [blame]6284
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6285 &lt;clause&gt; := catch &lt;type&gt; &lt;value&gt;
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6286 &lt;clause&gt; := filter &lt;array constant type&gt; &lt;array constant&gt;
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6287</pre>
6288
6289<h5>Overview:</h5>
6290<p>The '<tt>landingpad</tt>' instruction is used by
6291 <a href="ExceptionHandling.html#overview">LLVM's exception handling
6292 system</a> to specify that a basic block is a landing pad &mdash; one where
6293 the exception lands, and corresponds to the code found in the
6294 <i><tt>catch</tt></i> portion of a <i><tt>try/catch</tt></i> sequence. It
6295 defines values supplied by the personality function (<tt>pers_fn</tt>) upon
6296 re-entry to the function. The <tt>resultval</tt> has the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6297 type <tt>resultty</tt>.</p>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6298
6299<h5>Arguments:</h5>
6300<p>This instruction takes a <tt>pers_fn</tt> value. This is the personality
6301 function associated with the unwinding mechanism. The optional
6302 <tt>cleanup</tt> flag indicates that the landing pad block is a cleanup.</p>
6303
6304<p>A <tt>clause</tt> begins with the clause type &mdash; <tt>catch</tt>
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6305 or <tt>filter</tt> &mdash; and contains the global variable representing the
6306 "type" that may be caught or filtered respectively. Unlike the
6307 <tt>catch</tt> clause, the <tt>filter</tt> clause takes an array constant as
6308 its argument. Use "<tt>[0 x i8**] undef</tt>" for a filter which cannot
6309 throw. The '<tt>landingpad</tt>' instruction must contain <em>at least</em>
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6310 one <tt>clause</tt> or the <tt>cleanup</tt> flag.</p>
6311
6312<h5>Semantics:</h5>
6313<p>The '<tt>landingpad</tt>' instruction defines the values which are set by the
6314 personality function (<tt>pers_fn</tt>) upon re-entry to the function, and
6315 therefore the "result type" of the <tt>landingpad</tt> instruction. As with
6316 calling conventions, how the personality function results are represented in
6317 LLVM IR is target specific.</p>
6318
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6319<p>The clauses are applied in order from top to bottom. If two
6320 <tt>landingpad</tt> instructions are merged together through inlining, the
Duncan Sandsdf9d7812012-01-13 19:59:16 +0000[diff] [blame]6321 clauses from the calling function are appended to the list of clauses.
6322 When the call stack is being unwound due to an exception being thrown, the
6323 exception is compared against each <tt>clause</tt> in turn. If it doesn't
6324 match any of the clauses, and the <tt>cleanup</tt> flag is not set, then
6325 unwinding continues further up the call stack.</p>
Bill Wendling0524b8d2011-08-03 17:17:06 +0000[diff] [blame]6326
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6327<p>The <tt>landingpad</tt> instruction has several restrictions:</p>
6328
6329<ul>
6330 <li>A landing pad block is a basic block which is the unwind destination of an
6331 '<tt>invoke</tt>' instruction.</li>
6332 <li>A landing pad block must have a '<tt>landingpad</tt>' instruction as its
6333 first non-PHI instruction.</li>
6334 <li>There can be only one '<tt>landingpad</tt>' instruction within the landing
6335 pad block.</li>
6336 <li>A basic block that is not a landing pad block may not include a
6337 '<tt>landingpad</tt>' instruction.</li>
6338 <li>All '<tt>landingpad</tt>' instructions in a function must have the same
6339 personality function.</li>
6340</ul>
6341
6342<h5>Example:</h5>
6343<pre>
6344 ;; A landing pad which can catch an integer.
6345 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6346 catch i8** @_ZTIi
6347 ;; A landing pad that is a cleanup.
6348 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6349 cleanup
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6350 ;; A landing pad which can catch an integer and can only throw a double.
6351 %res = landingpad { i8*, i32 } personality i32 (...)* @__gxx_personality_v0
6352 catch i8** @_ZTIi
Bill Wendlingfae14752011-08-12 20:24:12 +0000[diff] [blame]6353 filter [1 x i8**] [@_ZTId]
Bill Wendlingbbcb7cd2011-08-02 21:52:38 +0000[diff] [blame]6354</pre>
6355
6356</div>
6357
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6358</div>
6359
6360</div>
6361
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6362<!-- *********************************************************************** -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6363<h2><a name="intrinsics">Intrinsic Functions</a></h2>
Chris Lattner48b383b02003-11-25 01:02:51 +0000[diff] [blame]6364<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6365
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6366<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6367
6368<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6369 well known names and semantics and are required to follow certain
6370 restrictions. Overall, these intrinsics represent an extension mechanism for
6371 the LLVM language that does not require changing all of the transformations
6372 in LLVM when adding to the language (or the bitcode reader/writer, the
6373 parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6374
John Criswell88190562005-05-16 16:17:45 +0000[diff] [blame]6375<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6376 prefix is reserved in LLVM for intrinsic names; thus, function names may not
6377 begin with this prefix. Intrinsic functions must always be external
6378 functions: you cannot define the body of intrinsic functions. Intrinsic
6379 functions may only be used in call or invoke instructions: it is illegal to
6380 take the address of an intrinsic function. Additionally, because intrinsic
6381 functions are part of the LLVM language, it is required if any are added that
6382 they be documented here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6383
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6384<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
6385 family of functions that perform the same operation but on different data
6386 types. Because LLVM can represent over 8 million different integer types,
6387 overloading is used commonly to allow an intrinsic function to operate on any
6388 integer type. One or more of the argument types or the result type can be
6389 overloaded to accept any integer type. Argument types may also be defined as
6390 exactly matching a previous argument's type or the result type. This allows
6391 an intrinsic function which accepts multiple arguments, but needs all of them
6392 to be of the same type, to only be overloaded with respect to a single
6393 argument or the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6394
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6395<p>Overloaded intrinsics will have the names of its overloaded argument types
6396 encoded into its function name, each preceded by a period. Only those types
6397 which are overloaded result in a name suffix. Arguments whose type is matched
6398 against another type do not. For example, the <tt>llvm.ctpop</tt> function
6399 can take an integer of any width and returns an integer of exactly the same
6400 integer width. This leads to a family of functions such as
6401 <tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
6402 %val)</tt>. Only one type, the return type, is overloaded, and only one type
6403 suffix is required. Because the argument's type is matched against the return
6404 type, it does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]6405
Eric Christopher455c5772009-12-05 02:46:03 +0000[diff] [blame]6406<p>To learn how to add an intrinsic function, please see the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6407 <a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6408
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6409<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6410<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6411 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6412</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6413
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6414<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6415
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6416<p>Variable argument support is defined in LLVM with
6417 the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
6418 intrinsic functions. These functions are related to the similarly named
6419 macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6420
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6421<p>All of these functions operate on arguments that use a target-specific value
6422 type "<tt>va_list</tt>". The LLVM assembly language reference manual does
6423 not define what this type is, so all transformations should be prepared to
6424 handle these functions regardless of the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6425
Chris Lattner30b868d2006-05-15 17:26:46 +0000[diff] [blame]6426<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6427 instruction and the variable argument handling intrinsic functions are
6428 used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6429
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]6430<pre class="doc_code">
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6431define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6432 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6433 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6434 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6435 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6436
6437 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6438 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6439
6440 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6441 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6442 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6443 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6444 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6445
6446 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6447 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000[diff] [blame]6448 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6449}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +0000[diff] [blame]6450
6451declare void @llvm.va_start(i8*)
6452declare void @llvm.va_copy(i8*, i8*)
6453declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6454</pre>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6455
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6456<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6457<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6458 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6459</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6460
6461
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6462<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6463
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6464<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6465<pre>
6466 declare void %llvm.va_start(i8* &lt;arglist&gt;)
6467</pre>
6468
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6469<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6470<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*&lt;arglist&gt;</tt>
6471 for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6472
6473<h5>Arguments:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6474<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6475
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6476<h5>Semantics:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000[diff] [blame]6477<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6478 macro available in C. In a target-dependent way, it initializes
6479 the <tt>va_list</tt> element to which the argument points, so that the next
6480 call to <tt>va_arg</tt> will produce the first variable argument passed to
6481 the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
6482 need to know the last argument of the function as the compiler can figure
6483 that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6484
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6485</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6486
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6487<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6488<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6489 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6490</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6491
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6492<div>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6493
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6494<h5>Syntax:</h5>
6495<pre>
6496 declare void @llvm.va_end(i8* &lt;arglist&gt;)
6497</pre>
6498
6499<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6500<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6501 which has been initialized previously
6502 with <tt><a href="#int_va_start">llvm.va_start</a></tt>
6503 or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6504
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6505<h5>Arguments:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6506<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]6507
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6508<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6509<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6510 macro available in C. In a target-dependent way, it destroys
6511 the <tt>va_list</tt> element to which the argument points. Calls
6512 to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
6513 and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
6514 with calls to <tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +0000[diff] [blame]6515
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6516</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6517
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6518<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6519<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6520 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6521</h4>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6522
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6523<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6524
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6525<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6526<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6527 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6528</pre>
6529
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6530<h5>Overview:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6531<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6532 from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6533
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6534<h5>Arguments:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +0000[diff] [blame]6535<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6536 The second argument is a pointer to a <tt>va_list</tt> element to copy
6537 from.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6538
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000[diff] [blame]6539<h5>Semantics:</h5>
Jeff Cohen222a8a42007-04-29 01:07:00 +0000[diff] [blame]6540<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6541 macro available in C. In a target-dependent way, it copies the
6542 source <tt>va_list</tt> element into the destination <tt>va_list</tt>
6543 element. This intrinsic is necessary because
6544 the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
6545 arbitrarily complex and require, for example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6546
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]6547</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]6548
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6549</div>
6550
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6551<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6552<h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6553 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6554</h3>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6555
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6556<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6557
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6558<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +0000[diff] [blame]6559Collection</a> (GC) requires the implementation and generation of these
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6560intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
6561roots on the stack</a>, as well as garbage collector implementations that
6562require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
6563barriers. Front-ends for type-safe garbage collected languages should generate
6564these intrinsics to make use of the LLVM garbage collectors. For more details,
6565see <a href="GarbageCollection.html">Accurate Garbage Collection with
6566LLVM</a>.</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6567
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6568<p>The garbage collection intrinsics only operate on objects in the generic
6569 address space (address space zero).</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +0000[diff] [blame]6570
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6571<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6572<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6573 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6574</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6575
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6576<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6577
6578<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6579<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6580 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6581</pre>
6582
6583<h5>Overview:</h5>
John Criswelldfe6a862004-12-10 15:51:16 +0000[diff] [blame]6584<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6585 the code generator, and allows some metadata to be associated with it.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6586
6587<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6588<p>The first argument specifies the address of a stack object that contains the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6589 root pointer. The second pointer (which must be either a constant or a
6590 global value address) contains the meta-data to be associated with the
6591 root.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6592
6593<h5>Semantics:</h5>
Chris Lattner851b7712008-04-24 05:59:56 +0000[diff] [blame]6594<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6595 location. At compile-time, the code generator generates information to allow
6596 the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
6597 intrinsic may only be used in a function which <a href="#gc">specifies a GC
6598 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6599
6600</div>
6601
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6602<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6603<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6604 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6605</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6606
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6607<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6608
6609<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6610<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6611 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6612</pre>
6613
6614<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6615<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6616 locations, allowing garbage collector implementations that require read
6617 barriers.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6618
6619<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6620<p>The second argument is the address to read from, which should be an address
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6621 allocated from the garbage collector. The first object is a pointer to the
6622 start of the referenced object, if needed by the language runtime (otherwise
6623 null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6624
6625<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6626<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6627 instruction, but may be replaced with substantially more complex code by the
6628 garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
6629 may only be used in a function which <a href="#gc">specifies a GC
6630 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6631
6632</div>
6633
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6634<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6635<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6636 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6637</h4>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6638
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6639<div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6640
6641<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6642<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6643 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6644</pre>
6645
6646<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6647<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6648 locations, allowing garbage collector implementations that require write
6649 barriers (such as generational or reference counting collectors).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6650
6651<h5>Arguments:</h5>
Chris Lattnerf9228072006-03-14 20:02:51 +0000[diff] [blame]6652<p>The first argument is the reference to store, the second is the start of the
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6653 object to store it to, and the third is the address of the field of Obj to
6654 store to. If the runtime does not require a pointer to the object, Obj may
6655 be null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6656
6657<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6658<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6659 instruction, but may be replaced with substantially more complex code by the
6660 garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
6661 may only be used in a function which <a href="#gc">specifies a GC
6662 algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6663
6664</div>
6665
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6666</div>
6667
Chris Lattner757528b0b2004-05-23 21:06:01 +0000[diff] [blame]6668<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6669<h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6670 <a name="int_codegen">Code Generator Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6671</h3>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6672
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6673<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6674
6675<p>These intrinsics are provided by LLVM to expose special features that may
6676 only be implemented with code generator support.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6677
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6678<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6679<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6680 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6681</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6682
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6683<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6684
6685<h5>Syntax:</h5>
6686<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]6687 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6688</pre>
6689
6690<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6691<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
6692 target-specific value indicating the return address of the current function
6693 or one of its callers.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6694
6695<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6696<p>The argument to this intrinsic indicates which function to return the address
6697 for. Zero indicates the calling function, one indicates its caller, etc.
6698 The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6699
6700<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6701<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
6702 indicating the return address of the specified call frame, or zero if it
6703 cannot be identified. The value returned by this intrinsic is likely to be
6704 incorrect or 0 for arguments other than zero, so it should only be used for
6705 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6706
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6707<p>Note that calling this intrinsic does not prevent function inlining or other
6708 aggressive transformations, so the value returned may not be that of the
6709 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6710
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6711</div>
6712
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6713<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6714<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6715 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6716</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6717
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6718<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6719
6720<h5>Syntax:</h5>
6721<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6722 declare i8* @llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6723</pre>
6724
6725<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6726<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
6727 target-specific frame pointer value for the specified stack frame.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6728
6729<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6730<p>The argument to this intrinsic indicates which function to return the frame
6731 pointer for. Zero indicates the calling function, one indicates its caller,
6732 etc. The argument is <b>required</b> to be a constant integer value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6733
6734<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6735<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
6736 indicating the frame address of the specified call frame, or zero if it
6737 cannot be identified. The value returned by this intrinsic is likely to be
6738 incorrect or 0 for arguments other than zero, so it should only be used for
6739 debugging purposes.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6740
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6741<p>Note that calling this intrinsic does not prevent function inlining or other
6742 aggressive transformations, so the value returned may not be that of the
6743 obvious source-language caller.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6744
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6745</div>
6746
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6747<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6748<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6749 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6750</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6751
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6752<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6753
6754<h5>Syntax:</h5>
6755<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6756 declare i8* @llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6757</pre>
6758
6759<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6760<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
6761 of the function stack, for use
6762 with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
6763 useful for implementing language features like scoped automatic variable
6764 sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6765
6766<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6767<p>This intrinsic returns a opaque pointer value that can be passed
6768 to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
6769 an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
6770 from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
6771 to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
6772 In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
6773 stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6774
6775</div>
6776
6777<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6778<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6779 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6780</h4>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6781
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6782<div>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6783
6784<h5>Syntax:</h5>
6785<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6786 declare void @llvm.stackrestore(i8* %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6787</pre>
6788
6789<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6790<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
6791 the function stack to the state it was in when the
6792 corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
6793 executed. This is useful for implementing language features like scoped
6794 automatic variable sized arrays in C99.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6795
6796<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6797<p>See the description
6798 for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6799
6800</div>
6801
Chris Lattner2f0f0012006-01-13 02:03:13 +0000[diff] [blame]6802<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6803<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6804 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6805</h4>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6806
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6807<div>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6808
6809<h5>Syntax:</h5>
6810<pre>
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6811 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;, i32 &lt;cache type&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6812</pre>
6813
6814<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6815<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
6816 insert a prefetch instruction if supported; otherwise, it is a noop.
6817 Prefetches have no effect on the behavior of the program but can change its
6818 performance characteristics.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6819
6820<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6821<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
6822 specifier determining if the fetch should be for a read (0) or write (1),
6823 and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Bruno Cardoso Lopesdc9ff3a2011-06-14 04:58:37 +0000[diff] [blame]6824 locality, to (3) - extremely local keep in cache. The <tt>cache type</tt>
6825 specifies whether the prefetch is performed on the data (1) or instruction (0)
6826 cache. The <tt>rw</tt>, <tt>locality</tt> and <tt>cache type</tt> arguments
6827 must be constant integers.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6828
6829<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6830<p>This intrinsic does not modify the behavior of the program. In particular,
6831 prefetches cannot trap and do not produce a value. On targets that support
6832 this intrinsic, the prefetch can provide hints to the processor cache for
6833 better performance.</p>
Chris Lattnerc8a2c222005-02-28 19:24:19 +0000[diff] [blame]6834
6835</div>
6836
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6837<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6838<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6839 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6840</h4>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6841
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6842<div>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6843
6844<h5>Syntax:</h5>
6845<pre>
Chris Lattner12477732007-09-21 17:30:40 +0000[diff] [blame]6846 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6847</pre>
6848
6849<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6850<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
6851 Counter (PC) in a region of code to simulators and other tools. The method
6852 is target specific, but it is expected that the marker will use exported
6853 symbols to transmit the PC of the marker. The marker makes no guarantees
6854 that it will remain with any specific instruction after optimizations. It is
6855 possible that the presence of a marker will inhibit optimizations. The
6856 intended use is to be inserted after optimizations to allow correlations of
6857 simulation runs.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6858
6859<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6860<p><tt>id</tt> is a numerical id identifying the marker.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6861
6862<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6863<p>This intrinsic does not modify the behavior of the program. Backends that do
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6864 not support this intrinsic may ignore it.</p>
Andrew Lenharthb4427912005-03-28 20:05:49 +0000[diff] [blame]6865
6866</div>
6867
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6868<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6869<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6870 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6871</h4>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6872
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6873<div>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6874
6875<h5>Syntax:</h5>
6876<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]6877 declare i64 @llvm.readcyclecounter()
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6878</pre>
6879
6880<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6881<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
6882 counter register (or similar low latency, high accuracy clocks) on those
6883 targets that support it. On X86, it should map to RDTSC. On Alpha, it
6884 should map to RPCC. As the backing counters overflow quickly (on the order
6885 of 9 seconds on alpha), this should only be used for small timings.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6886
6887<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6888<p>When directly supported, reading the cycle counter should not modify any
6889 memory. Implementations are allowed to either return a application specific
6890 value or a system wide value. On backends without support, this is lowered
6891 to a constant 0.</p>
Andrew Lenharth01aa5632005-11-11 16:47:30 +0000[diff] [blame]6892
6893</div>
6894
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6895</div>
6896
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]6897<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6898<h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6899 <a name="int_libc">Standard C Library Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6900</h3>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6901
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6902<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6903
6904<p>LLVM provides intrinsics for a few important standard C library functions.
6905 These intrinsics allow source-language front-ends to pass information about
6906 the alignment of the pointer arguments to the code generator, providing
6907 opportunity for more efficient code generation.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6908
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6909<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6910<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6911 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6912</h4>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6913
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6914<div>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6915
6916<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6917<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6918 integer bit width and for different address spaces. Not all targets support
6919 all bit widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6920
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6921<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6922 declare void @llvm.memcpy.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6923 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6924 declare void @llvm.memcpy.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6925 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6926</pre>
6927
6928<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6929<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6930 source location to the destination location.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6931
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6932<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6933 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6934 and the pointers can be in specified address spaces.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6935
6936<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6937
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6938<p>The first argument is a pointer to the destination, the second is a pointer
6939 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6940 number of bytes to copy, the fourth argument is the alignment of the
6941 source and destination locations, and the fifth is a boolean indicating a
6942 volatile access.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6943
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]6944<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6945 then the caller guarantees that both the source and destination pointers are
6946 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]6947
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]6948<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
6949 <tt>llvm.memcpy</tt> call is a <a href="#volatile">volatile operation</a>.
6950 The detailed access behavior is not very cleanly specified and it is unwise
6951 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6952
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6953<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6954
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6955<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
6956 source location to the destination location, which are not allowed to
6957 overlap. It copies "len" bytes of memory over. If the argument is known to
6958 be aligned to some boundary, this can be specified as the fourth argument,
6959 otherwise it should be set to 0 or 1.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6960
Chris Lattnerfee11462004-02-12 17:01:32 +0000[diff] [blame]6961</div>
6962
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6963<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6964<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]6965 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]6966</h4>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6967
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]6968<div>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6969
6970<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]6971<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Mon P Wang508127b2010-04-07 06:35:53 +0000[diff] [blame]6972 width and for different address space. Not all targets support all bit
6973 widths however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6974
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6975<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6976 declare void @llvm.memmove.p0i8.p0i8.i32(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6977 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]6978 declare void @llvm.memmove.p0i8.p0i8.i64(i8* &lt;dest&gt;, i8* &lt;src&gt;,
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6979 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6980</pre>
6981
6982<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6983<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
6984 source location to the destination location. It is similar to the
6985 '<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
6986 overlap.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6987
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6988<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6989 intrinsics do not return a value, takes extra alignment/isvolatile arguments
6990 and the pointers can be in specified address spaces.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6991
6992<h5>Arguments:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6993
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]6994<p>The first argument is a pointer to the destination, the second is a pointer
6995 to the source. The third argument is an integer argument specifying the
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]6996 number of bytes to copy, the fourth argument is the alignment of the
6997 source and destination locations, and the fifth is a boolean indicating a
6998 volatile access.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]6999
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7000<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7001 then the caller guarantees that the source and destination pointers are
7002 aligned to that boundary.</p>
Chris Lattner4c67c482004-02-12 21:18:15 +0000[diff] [blame]7003
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7004<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7005 <tt>llvm.memmove</tt> call is a <a href="#volatile">volatile operation</a>.
7006 The detailed access behavior is not very cleanly specified and it is unwise
7007 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7008
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7009<h5>Semantics:</h5>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7010
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7011<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
7012 source location to the destination location, which may overlap. It copies
7013 "len" bytes of memory over. If the argument is known to be aligned to some
7014 boundary, this can be specified as the fourth argument, otherwise it should
7015 be set to 0 or 1.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7016
Chris Lattnerf30152e2004-02-12 18:10:10 +0000[diff] [blame]7017</div>
7018
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7019<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7020<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7021 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7022</h4>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7023
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7024<div>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7025
7026<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +0000[diff] [blame]7027<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7028 width and for different address spaces. However, not all targets support all
7029 bit widths.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7030
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7031<pre>
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7032 declare void @llvm.memset.p0i8.i32(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7033 i32 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Dan Gohmanaabfdb32010-05-28 17:13:49 +0000[diff] [blame]7034 declare void @llvm.memset.p0i8.i64(i8* &lt;dest&gt;, i8 &lt;val&gt;,
Chris Lattner685db9d2010-04-08 00:54:34 +0000[diff] [blame]7035 i64 &lt;len&gt;, i32 &lt;align&gt;, i1 &lt;isvolatile&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7036</pre>
7037
7038<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7039<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
7040 particular byte value.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7041
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7042<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7043 intrinsic does not return a value and takes extra alignment/volatile
7044 arguments. Also, the destination can be in an arbitrary address space.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7045
7046<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7047<p>The first argument is a pointer to the destination to fill, the second is the
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7048 byte value with which to fill it, the third argument is an integer argument
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7049 specifying the number of bytes to fill, and the fourth argument is the known
John Criswellad05ae42010-07-30 16:30:28 +0000[diff] [blame]7050 alignment of the destination location.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7051
Dan Gohmana269a0a2010-03-01 17:41:39 +0000[diff] [blame]7052<p>If the call to this intrinsic has an alignment value that is not 0 or 1,
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7053 then the caller guarantees that the destination pointer is aligned to that
7054 boundary.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7055
Jeffrey Yasskin5d284ae2010-04-26 21:21:24 +0000[diff] [blame]7056<p>If the <tt>isvolatile</tt> parameter is <tt>true</tt>, the
7057 <tt>llvm.memset</tt> call is a <a href="#volatile">volatile operation</a>.
7058 The detailed access behavior is not very cleanly specified and it is unwise
7059 to depend on it.</p>
Chris Lattnerbd4ca622010-04-08 00:53:57 +0000[diff] [blame]7060
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7061<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7062<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
7063 at the destination location. If the argument is known to be aligned to some
7064 boundary, this can be specified as the fourth argument, otherwise it should
7065 be set to 0 or 1.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7066
Chris Lattner3649c3a2004-02-14 04:08:35 +0000[diff] [blame]7067</div>
7068
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7069<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7070<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7071 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7072</h4>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7073
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7074<div>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7075
7076<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7077<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
7078 floating point or vector of floating point type. Not all targets support all
7079 types however.</p>
7080
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7081<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7082 declare float @llvm.sqrt.f32(float %Val)
7083 declare double @llvm.sqrt.f64(double %Val)
7084 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
7085 declare fp128 @llvm.sqrt.f128(fp128 %Val)
7086 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7087</pre>
7088
7089<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7090<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
7091 returning the same value as the libm '<tt>sqrt</tt>' functions would.
7092 Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
7093 behavior for negative numbers other than -0.0 (which allows for better
7094 optimization, because there is no need to worry about errno being
7095 set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7096
7097<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7098<p>The argument and return value are floating point numbers of the same
7099 type.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7100
7101<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7102<p>This function returns the sqrt of the specified operand if it is a
7103 nonnegative floating point number.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7104
Chris Lattner8a8f2e52005-07-21 01:29:16 +0000[diff] [blame]7105</div>
7106
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7107<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7108<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7109 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7110</h4>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7111
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7112<div>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7113
7114<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7115<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
7116 floating point or vector of floating point type. Not all targets support all
7117 types however.</p>
7118
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7119<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +0000[diff] [blame]7120 declare float @llvm.powi.f32(float %Val, i32 %power)
7121 declare double @llvm.powi.f64(double %Val, i32 %power)
7122 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
7123 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
7124 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7125</pre>
7126
7127<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7128<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
7129 specified (positive or negative) power. The order of evaluation of
7130 multiplications is not defined. When a vector of floating point type is
7131 used, the second argument remains a scalar integer value.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7132
7133<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7134<p>The second argument is an integer power, and the first is a value to raise to
7135 that power.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7136
7137<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7138<p>This function returns the first value raised to the second power with an
7139 unspecified sequence of rounding operations.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7140
Chris Lattner33b73f92006-09-08 06:34:02 +0000[diff] [blame]7141</div>
7142
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7143<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7144<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7145 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7146</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7147
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7148<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7149
7150<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7151<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
7152 floating point or vector of floating point type. Not all targets support all
7153 types however.</p>
7154
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7155<pre>
7156 declare float @llvm.sin.f32(float %Val)
7157 declare double @llvm.sin.f64(double %Val)
7158 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
7159 declare fp128 @llvm.sin.f128(fp128 %Val)
7160 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
7161</pre>
7162
7163<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7164<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7165
7166<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7167<p>The argument and return value are floating point numbers of the same
7168 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7169
7170<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7171<p>This function returns the sine of the specified operand, returning the same
7172 values as the libm <tt>sin</tt> functions would, and handles error conditions
7173 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7174
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7175</div>
7176
7177<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7178<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7179 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7180</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7181
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7182<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7183
7184<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7185<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
7186 floating point or vector of floating point type. Not all targets support all
7187 types however.</p>
7188
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7189<pre>
7190 declare float @llvm.cos.f32(float %Val)
7191 declare double @llvm.cos.f64(double %Val)
7192 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
7193 declare fp128 @llvm.cos.f128(fp128 %Val)
7194 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
7195</pre>
7196
7197<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7198<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7199
7200<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7201<p>The argument and return value are floating point numbers of the same
7202 type.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7203
7204<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7205<p>This function returns the cosine of the specified operand, returning the same
7206 values as the libm <tt>cos</tt> functions would, and handles error conditions
7207 in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7208
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7209</div>
7210
7211<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7212<h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7213 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7214</h4>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7215
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7216<div>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7217
7218<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7219<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
7220 floating point or vector of floating point type. Not all targets support all
7221 types however.</p>
7222
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7223<pre>
7224 declare float @llvm.pow.f32(float %Val, float %Power)
7225 declare double @llvm.pow.f64(double %Val, double %Power)
7226 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
7227 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
7228 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
7229</pre>
7230
7231<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7232<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
7233 specified (positive or negative) power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7234
7235<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7236<p>The second argument is a floating point power, and the first is a value to
7237 raise to that power.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7238
7239<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7240<p>This function returns the first value raised to the second power, returning
7241 the same values as the libm <tt>pow</tt> functions would, and handles error
7242 conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7243
Dan Gohmanb6324c12007-10-15 20:30:11 +0000[diff] [blame]7244</div>
7245
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7246<!-- _______________________________________________________________________ -->
7247<h4>
7248 <a name="int_exp">'<tt>llvm.exp.*</tt>' Intrinsic</a>
7249</h4>
7250
7251<div>
7252
7253<h5>Syntax:</h5>
7254<p>This is an overloaded intrinsic. You can use <tt>llvm.exp</tt> on any
7255 floating point or vector of floating point type. Not all targets support all
7256 types however.</p>
7257
7258<pre>
7259 declare float @llvm.exp.f32(float %Val)
7260 declare double @llvm.exp.f64(double %Val)
7261 declare x86_fp80 @llvm.exp.f80(x86_fp80 %Val)
7262 declare fp128 @llvm.exp.f128(fp128 %Val)
7263 declare ppc_fp128 @llvm.exp.ppcf128(ppc_fp128 %Val)
7264</pre>
7265
7266<h5>Overview:</h5>
7267<p>The '<tt>llvm.exp.*</tt>' intrinsics perform the exp function.</p>
7268
7269<h5>Arguments:</h5>
7270<p>The argument and return value are floating point numbers of the same
7271 type.</p>
7272
7273<h5>Semantics:</h5>
7274<p>This function returns the same values as the libm <tt>exp</tt> functions
7275 would, and handles error conditions in the same way.</p>
7276
7277</div>
7278
7279<!-- _______________________________________________________________________ -->
7280<h4>
7281 <a name="int_log">'<tt>llvm.log.*</tt>' Intrinsic</a>
7282</h4>
7283
7284<div>
7285
7286<h5>Syntax:</h5>
7287<p>This is an overloaded intrinsic. You can use <tt>llvm.log</tt> on any
7288 floating point or vector of floating point type. Not all targets support all
7289 types however.</p>
7290
7291<pre>
7292 declare float @llvm.log.f32(float %Val)
7293 declare double @llvm.log.f64(double %Val)
7294 declare x86_fp80 @llvm.log.f80(x86_fp80 %Val)
7295 declare fp128 @llvm.log.f128(fp128 %Val)
7296 declare ppc_fp128 @llvm.log.ppcf128(ppc_fp128 %Val)
7297</pre>
7298
7299<h5>Overview:</h5>
7300<p>The '<tt>llvm.log.*</tt>' intrinsics perform the log function.</p>
7301
7302<h5>Arguments:</h5>
7303<p>The argument and return value are floating point numbers of the same
7304 type.</p>
7305
7306<h5>Semantics:</h5>
7307<p>This function returns the same values as the libm <tt>log</tt> functions
7308 would, and handles error conditions in the same way.</p>
7309
Nick Lewyckycd196f62011-10-31 01:32:21 +0000[diff] [blame]7310</div>
7311
7312<!-- _______________________________________________________________________ -->
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7313<h4>
7314 <a name="int_fma">'<tt>llvm.fma.*</tt>' Intrinsic</a>
7315</h4>
7316
7317<div>
7318
7319<h5>Syntax:</h5>
7320<p>This is an overloaded intrinsic. You can use <tt>llvm.fma</tt> on any
7321 floating point or vector of floating point type. Not all targets support all
7322 types however.</p>
7323
7324<pre>
7325 declare float @llvm.fma.f32(float %a, float %b, float %c)
7326 declare double @llvm.fma.f64(double %a, double %b, double %c)
7327 declare x86_fp80 @llvm.fma.f80(x86_fp80 %a, x86_fp80 %b, x86_fp80 %c)
7328 declare fp128 @llvm.fma.f128(fp128 %a, fp128 %b, fp128 %c)
7329 declare ppc_fp128 @llvm.fma.ppcf128(ppc_fp128 %a, ppc_fp128 %b, ppc_fp128 %c)
7330</pre>
7331
7332<h5>Overview:</h5>
Cameron Zwaricha32fd212011-07-08 22:13:55 +0000[diff] [blame]7333<p>The '<tt>llvm.fma.*</tt>' intrinsics perform the fused multiply-add
Cameron Zwarichf03fa182011-07-08 21:39:21 +0000[diff] [blame]7334 operation.</p>
7335
7336<h5>Arguments:</h5>
7337<p>The argument and return value are floating point numbers of the same
7338 type.</p>
7339
7340<h5>Semantics:</h5>
7341<p>This function returns the same values as the libm <tt>fma</tt> functions
7342 would.</p>
7343
Dan Gohman911fa902011-05-23 21:13:03 +0000[diff] [blame]7344</div>
7345
NAKAMURA Takumia35cdd62011-10-31 13:04:26 +0000[diff] [blame]7346</div>
7347
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7348<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7349<h3>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7350 <a name="int_manip">Bit Manipulation Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7351</h3>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7352
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7353<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7354
7355<p>LLVM provides intrinsics for a few important bit manipulation operations.
7356 These allow efficient code generation for some algorithms.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7357
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7358<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7359<h4>
Reid Spencer96a5f022007-04-04 02:42:35 +0000[diff] [blame]7360 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7361</h4>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7362
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7363<div>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7364
7365<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7366<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7367 type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
7368
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7369<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7370 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
7371 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
7372 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7373</pre>
7374
7375<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7376<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
7377 values with an even number of bytes (positive multiple of 16 bits). These
7378 are useful for performing operations on data that is not in the target's
7379 native byte order.</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7380
7381<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7382<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
7383 and low byte of the input i16 swapped. Similarly,
7384 the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
7385 bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
7386 2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
7387 The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
7388 extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
7389 more, respectively).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000[diff] [blame]7390
7391</div>
7392
7393<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7394<h4>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +0000[diff] [blame]7395 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7396</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7397
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7398<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7399
7400<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +0000[diff] [blame]7401<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7402 width, or on any vector with integer elements. Not all targets support all
7403 bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7404
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7405<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7406 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7407 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +0000[diff] [blame]7408 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +0000[diff] [blame]7409 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
7410 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7411 declare &lt;2 x i32&gt; @llvm.ctpop.v2i32(&lt;2 x i32&gt; &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7412</pre>
7413
7414<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7415<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
7416 in a value.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7417
7418<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7419<p>The only argument is the value to be counted. The argument may be of any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7420 integer type, or a vector with integer elements.
7421 The return type must match the argument type.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7422
7423<h5>Semantics:</h5>
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7424<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable, or within each
7425 element of a vector.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7426
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7427</div>
7428
7429<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7430<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7431 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7432</h4>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7433
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7434<div>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7435
7436<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7437<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7438 integer bit width, or any vector whose elements are integers. Not all
7439 targets support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7440
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7441<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7442 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7443 declare i16 @llvm.ctlz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7444 declare i32 @llvm.ctlz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7445 declare i64 @llvm.ctlz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7446 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7447 declase &lt;2 x i32&gt; @llvm.ctlz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7448</pre>
7449
7450<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7451<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
7452 leading zeros in a variable.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7453
7454<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7455<p>The first argument is the value to be counted. This argument may be of any
7456 integer type, or a vectory with integer element type. The return type
7457 must match the first argument type.</p>
7458
7459<p>The second argument must be a constant and is a flag to indicate whether the
7460 intrinsic should ensure that a zero as the first argument produces a defined
7461 result. Historically some architectures did not provide a defined result for
7462 zero values as efficiently, and many algorithms are now predicated on
7463 avoiding zero-value inputs.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7464
7465<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7466<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7467 zeros in a variable, or within each element of the vector.
7468 If <tt>src == 0</tt> then the result is the size in bits of the type of
7469 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7470 For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7471
Andrew Lenharth1d463522005-05-03 18:01:48 +0000[diff] [blame]7472</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +0000[diff] [blame]7473
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7474<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7475<h4>
Chris Lattnerb748c672006-01-16 22:34:14 +0000[diff] [blame]7476 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7477</h4>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7478
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7479<div>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7480
7481<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7482<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7483 integer bit width, or any vector of integer elements. Not all targets
7484 support all bit widths or vector types, however.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7485
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7486<pre>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7487 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7488 declare i16 @llvm.cttz.i16 (i16 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7489 declare i32 @llvm.cttz.i32 (i32 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7490 declare i64 @llvm.cttz.i64 (i64 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7491 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
7492 declase &lt;2 x i32&gt; @llvm.cttz.v2i32(&lt;2 x i32&gt; &lt;src&gt;, i1 &lt;is_zero_undef&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7493</pre>
7494
7495<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7496<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
7497 trailing zeros.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7498
7499<h5>Arguments:</h5>
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7500<p>The first argument is the value to be counted. This argument may be of any
7501 integer type, or a vectory with integer element type. The return type
7502 must match the first argument type.</p>
7503
7504<p>The second argument must be a constant and is a flag to indicate whether the
7505 intrinsic should ensure that a zero as the first argument produces a defined
7506 result. Historically some architectures did not provide a defined result for
7507 zero values as efficiently, and many algorithms are now predicated on
7508 avoiding zero-value inputs.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7509
7510<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7511<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
Owen Anderson2f37bdc2011-07-01 21:52:38 +0000[diff] [blame]7512 zeros in a variable, or within each element of a vector.
Chandler Carruthf6bb2782011-12-12 04:36:04 +0000[diff] [blame]7513 If <tt>src == 0</tt> then the result is the size in bits of the type of
7514 <tt>src</tt> if <tt>is_zero_undef == 0</tt> and <tt>undef</tt> otherwise.
7515 For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7516
Chris Lattnerefa20fa2005-05-15 19:39:26 +0000[diff] [blame]7517</div>
7518
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7519</div>
7520
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7521<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7522<h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7523 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7524</h3>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7525
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7526<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7527
7528<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000[diff] [blame]7529
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7530<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7531<h4>
7532 <a name="int_sadd_overflow">
7533 '<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics
7534 </a>
7535</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7536
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7537<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7538
7539<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7540<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7541 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7542
7543<pre>
7544 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
7545 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7546 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
7547</pre>
7548
7549<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7550<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7551 a signed addition of the two arguments, and indicate whether an overflow
7552 occurred during the signed summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7553
7554<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7555<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7556 be of integer types of any bit width, but they must have the same bit
7557 width. The second element of the result structure must be of
7558 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7559 undergo signed addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7560
7561<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7562<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7563 a signed addition of the two variables. They return a structure &mdash; the
7564 first element of which is the signed summation, and the second element of
7565 which is a bit specifying if the signed summation resulted in an
7566 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7567
7568<h5>Examples:</h5>
7569<pre>
7570 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
7571 %sum = extractvalue {i32, i1} %res, 0
7572 %obit = extractvalue {i32, i1} %res, 1
7573 br i1 %obit, label %overflow, label %normal
7574</pre>
7575
7576</div>
7577
7578<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7579<h4>
7580 <a name="int_uadd_overflow">
7581 '<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics
7582 </a>
7583</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7584
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7585<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7586
7587<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7588<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7589 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7590
7591<pre>
7592 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
7593 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7594 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
7595</pre>
7596
7597<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7598<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7599 an unsigned addition of the two arguments, and indicate whether a carry
7600 occurred during the unsigned summation.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7601
7602<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7603<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7604 be of integer types of any bit width, but they must have the same bit
7605 width. The second element of the result structure must be of
7606 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7607 undergo unsigned addition.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7608
7609<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7610<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7611 an unsigned addition of the two arguments. They return a structure &mdash;
7612 the first element of which is the sum, and the second element of which is a
7613 bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7614
7615<h5>Examples:</h5>
7616<pre>
7617 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
7618 %sum = extractvalue {i32, i1} %res, 0
7619 %obit = extractvalue {i32, i1} %res, 1
7620 br i1 %obit, label %carry, label %normal
7621</pre>
7622
7623</div>
7624
7625<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7626<h4>
7627 <a name="int_ssub_overflow">
7628 '<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics
7629 </a>
7630</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7631
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7632<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7633
7634<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7635<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7636 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7637
7638<pre>
7639 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
7640 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7641 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
7642</pre>
7643
7644<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7645<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7646 a signed subtraction of the two arguments, and indicate whether an overflow
7647 occurred during the signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7648
7649<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7650<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7651 be of integer types of any bit width, but they must have the same bit
7652 width. The second element of the result structure must be of
7653 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7654 undergo signed subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7655
7656<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7657<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7658 a signed subtraction of the two arguments. They return a structure &mdash;
7659 the first element of which is the subtraction, and the second element of
7660 which is a bit specifying if the signed subtraction resulted in an
7661 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7662
7663<h5>Examples:</h5>
7664<pre>
7665 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
7666 %sum = extractvalue {i32, i1} %res, 0
7667 %obit = extractvalue {i32, i1} %res, 1
7668 br i1 %obit, label %overflow, label %normal
7669</pre>
7670
7671</div>
7672
7673<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7674<h4>
7675 <a name="int_usub_overflow">
7676 '<tt>llvm.usub.with.overflow.*</tt>' Intrinsics
7677 </a>
7678</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7679
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7680<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7681
7682<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7683<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7684 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7685
7686<pre>
7687 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
7688 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7689 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
7690</pre>
7691
7692<h5>Overview:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7693<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7694 an unsigned subtraction of the two arguments, and indicate whether an
7695 overflow occurred during the unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7696
7697<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7698<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7699 be of integer types of any bit width, but they must have the same bit
7700 width. The second element of the result structure must be of
7701 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7702 undergo unsigned subtraction.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7703
7704<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7705<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7706 an unsigned subtraction of the two arguments. They return a structure &mdash;
7707 the first element of which is the subtraction, and the second element of
7708 which is a bit specifying if the unsigned subtraction resulted in an
7709 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7710
7711<h5>Examples:</h5>
7712<pre>
7713 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
7714 %sum = extractvalue {i32, i1} %res, 0
7715 %obit = extractvalue {i32, i1} %res, 1
7716 br i1 %obit, label %overflow, label %normal
7717</pre>
7718
7719</div>
7720
7721<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7722<h4>
7723 <a name="int_smul_overflow">
7724 '<tt>llvm.smul.with.overflow.*</tt>' Intrinsics
7725 </a>
7726</h4>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7727
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7728<div>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7729
7730<h5>Syntax:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7731<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7732 on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7733
7734<pre>
7735 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
7736 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7737 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
7738</pre>
7739
7740<h5>Overview:</h5>
7741
7742<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7743 a signed multiplication of the two arguments, and indicate whether an
7744 overflow occurred during the signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7745
7746<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7747<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7748 be of integer types of any bit width, but they must have the same bit
7749 width. The second element of the result structure must be of
7750 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7751 undergo signed multiplication.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7752
7753<h5>Semantics:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7754<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7755 a signed multiplication of the two arguments. They return a structure &mdash;
7756 the first element of which is the multiplication, and the second element of
7757 which is a bit specifying if the signed multiplication resulted in an
7758 overflow.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000[diff] [blame]7759
7760<h5>Examples:</h5>
7761<pre>
7762 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
7763 %sum = extractvalue {i32, i1} %res, 0
7764 %obit = extractvalue {i32, i1} %res, 1
7765 br i1 %obit, label %overflow, label %normal
7766</pre>
7767
Reid Spencer5bf54c82007-04-11 23:23:49 +0000[diff] [blame]7768</div>
7769
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7770<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7771<h4>
7772 <a name="int_umul_overflow">
7773 '<tt>llvm.umul.with.overflow.*</tt>' Intrinsics
7774 </a>
7775</h4>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7776
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7777<div>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7778
7779<h5>Syntax:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7780<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7781 on any integer bit width.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7782
7783<pre>
7784 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
7785 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7786 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
7787</pre>
7788
7789<h5>Overview:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7790<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7791 a unsigned multiplication of the two arguments, and indicate whether an
7792 overflow occurred during the unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7793
7794<h5>Arguments:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7795<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7796 be of integer types of any bit width, but they must have the same bit
7797 width. The second element of the result structure must be of
7798 type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
7799 undergo unsigned multiplication.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7800
7801<h5>Semantics:</h5>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7802<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7803 an unsigned multiplication of the two arguments. They return a structure
7804 &mdash; the first element of which is the multiplication, and the second
7805 element of which is a bit specifying if the unsigned multiplication resulted
7806 in an overflow.</p>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000[diff] [blame]7807
7808<h5>Examples:</h5>
7809<pre>
7810 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
7811 %sum = extractvalue {i32, i1} %res, 0
7812 %obit = extractvalue {i32, i1} %res, 1
7813 br i1 %obit, label %overflow, label %normal
7814</pre>
7815
7816</div>
7817
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7818</div>
7819
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7820<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7821<h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7822 <a name="int_fp16">Half Precision Floating Point Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7823</h3>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7824
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7825<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7826
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7827<p>Half precision floating point is a storage-only format. This means that it is
7828 a dense encoding (in memory) but does not support computation in the
7829 format.</p>
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7830
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7831<p>This means that code must first load the half-precision floating point
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7832 value as an i16, then convert it to float with <a
7833 href="#int_convert_from_fp16"><tt>llvm.convert.from.fp16</tt></a>.
7834 Computation can then be performed on the float value (including extending to
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7835 double etc). To store the value back to memory, it is first converted to
7836 float if needed, then converted to i16 with
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7837 <a href="#int_convert_to_fp16"><tt>llvm.convert.to.fp16</tt></a>, then
7838 storing as an i16 value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7839
7840<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7841<h4>
7842 <a name="int_convert_to_fp16">
7843 '<tt>llvm.convert.to.fp16</tt>' Intrinsic
7844 </a>
7845</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7846
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7847<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7848
7849<h5>Syntax:</h5>
7850<pre>
7851 declare i16 @llvm.convert.to.fp16(f32 %a)
7852</pre>
7853
7854<h5>Overview:</h5>
7855<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7856 a conversion from single precision floating point format to half precision
7857 floating point format.</p>
7858
7859<h5>Arguments:</h5>
7860<p>The intrinsic function contains single argument - the value to be
7861 converted.</p>
7862
7863<h5>Semantics:</h5>
7864<p>The '<tt>llvm.convert.to.fp16</tt>' intrinsic function performs
7865 a conversion from single precision floating point format to half precision
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7866 floating point format. The return value is an <tt>i16</tt> which
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7867 contains the converted number.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7868
7869<h5>Examples:</h5>
7870<pre>
7871 %res = call i16 @llvm.convert.to.fp16(f32 %a)
7872 store i16 %res, i16* @x, align 2
7873</pre>
7874
7875</div>
7876
7877<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7878<h4>
7879 <a name="int_convert_from_fp16">
7880 '<tt>llvm.convert.from.fp16</tt>' Intrinsic
7881 </a>
7882</h4>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7883
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7884<div>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7885
7886<h5>Syntax:</h5>
7887<pre>
7888 declare f32 @llvm.convert.from.fp16(i16 %a)
7889</pre>
7890
7891<h5>Overview:</h5>
7892<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs
7893 a conversion from half precision floating point format to single precision
7894 floating point format.</p>
7895
7896<h5>Arguments:</h5>
7897<p>The intrinsic function contains single argument - the value to be
7898 converted.</p>
7899
7900<h5>Semantics:</h5>
7901<p>The '<tt>llvm.convert.from.fp16</tt>' intrinsic function performs a
Chris Lattner022a9fb2010-03-15 04:12:21 +0000[diff] [blame]7902 conversion from half single precision floating point format to single
Chris Lattnerbbd8bd32010-03-14 23:03:31 +0000[diff] [blame]7903 precision floating point format. The input half-float value is represented by
7904 an <tt>i16</tt> value.</p>
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7905
7906<h5>Examples:</h5>
7907<pre>
7908 %a = load i16* @x, align 2
7909 %res = call f32 @llvm.convert.from.fp16(i16 %a)
7910</pre>
7911
7912</div>
7913
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7914</div>
7915
Anton Korobeynikovcd4dd9c2010-03-14 18:42:47 +0000[diff] [blame]7916<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7917<h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7918 <a name="int_debugger">Debugger Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7919</h3>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7920
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7921<div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7922
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7923<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
7924 prefix), are described in
7925 the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
7926 Level Debugging</a> document.</p>
7927
7928</div>
Chris Lattner941515c2004-01-06 05:31:32 +0000[diff] [blame]7929
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7930<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7931<h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7932 <a name="int_eh">Exception Handling Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7933</h3>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7934
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7935<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7936
7937<p>The LLVM exception handling intrinsics (which all start with
7938 <tt>llvm.eh.</tt> prefix), are described in
7939 the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
7940 Handling</a> document.</p>
7941
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]7942</div>
7943
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]7944<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7945<h3>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7946 <a name="int_trampoline">Trampoline Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7947</h3>
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7948
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7949<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7950
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7951<p>These intrinsics make it possible to excise one parameter, marked with
Dan Gohman3770af52010-07-02 23:18:08 +0000[diff] [blame]7952 the <a href="#nest"><tt>nest</tt></a> attribute, from a function.
7953 The result is a callable
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7954 function pointer lacking the nest parameter - the caller does not need to
7955 provide a value for it. Instead, the value to use is stored in advance in a
7956 "trampoline", a block of memory usually allocated on the stack, which also
7957 contains code to splice the nest value into the argument list. This is used
7958 to implement the GCC nested function address extension.</p>
7959
7960<p>For example, if the function is
7961 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
7962 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
7963 follows:</p>
7964
Benjamin Kramer79698be2010-07-13 12:26:09 +0000[diff] [blame]7965<pre class="doc_code">
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7966 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
7967 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7968 call i8* @llvm.init.trampoline(i8* %tramp1, i8* bitcast (i32 (i8*, i32, i32)* @f to i8*), i8* %nval)
7969 %p = call i8* @llvm.adjust.trampoline(i8* %tramp1)
Duncan Sands86e01192007-09-11 14:10:23 +0000[diff] [blame]7970 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7971</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7972
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]7973<p>The call <tt>%val = call i32 %fp(i32 %x, i32 %y)</tt> is then equivalent
7974 to <tt>%val = call i32 %f(i8* %nval, i32 %x, i32 %y)</tt>.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7975
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7976<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]7977<h4>
7978 <a name="int_it">
7979 '<tt>llvm.init.trampoline</tt>' Intrinsic
7980 </a>
7981</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7982
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]7983<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7984
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7985<h5>Syntax:</h5>
7986<pre>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7987 declare void @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7988</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7989
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7990<h5>Overview:</h5>
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]7991<p>This fills the memory pointed to by <tt>tramp</tt> with executable code,
7992 turning it into a trampoline.</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7993
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]7994<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]7995<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
7996 pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
7997 sufficiently aligned block of memory; this memory is written to by the
7998 intrinsic. Note that the size and the alignment are target-specific - LLVM
7999 currently provides no portable way of determining them, so a front-end that
8000 generates this intrinsic needs to have some target-specific knowledge.
8001 The <tt>func</tt> argument must hold a function bitcast to
8002 an <tt>i8*</tt>.</p>
8003
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8004<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8005<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sandsa0984362011-09-06 13:37:06 +0000[diff] [blame]8006 dependent code, turning it into a function. Then <tt>tramp</tt> needs to be
8007 passed to <a href="#int_at">llvm.adjust.trampoline</a> to get a pointer
8008 which can be <a href="#int_trampoline">bitcast (to a new function) and
8009 called</a>. The new function's signature is the same as that of
8010 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
8011 removed. At most one such <tt>nest</tt> argument is allowed, and it must be of
8012 pointer type. Calling the new function is equivalent to calling <tt>func</tt>
8013 with the same argument list, but with <tt>nval</tt> used for the missing
8014 <tt>nest</tt> argument. If, after calling <tt>llvm.init.trampoline</tt>, the
8015 memory pointed to by <tt>tramp</tt> is modified, then the effect of any later call
8016 to the returned function pointer is undefined.</p>
8017</div>
8018
8019<!-- _______________________________________________________________________ -->
8020<h4>
8021 <a name="int_at">
8022 '<tt>llvm.adjust.trampoline</tt>' Intrinsic
8023 </a>
8024</h4>
8025
8026<div>
8027
8028<h5>Syntax:</h5>
8029<pre>
8030 declare i8* @llvm.adjust.trampoline(i8* &lt;tramp&gt;)
8031</pre>
8032
8033<h5>Overview:</h5>
8034<p>This performs any required machine-specific adjustment to the address of a
8035 trampoline (passed as <tt>tramp</tt>).</p>
8036
8037<h5>Arguments:</h5>
8038<p><tt>tramp</tt> must point to a block of memory which already has trampoline code
8039 filled in by a previous call to <a href="#int_it"><tt>llvm.init.trampoline</tt>
8040 </a>.</p>
8041
8042<h5>Semantics:</h5>
8043<p>On some architectures the address of the code to be executed needs to be
8044 different to the address where the trampoline is actually stored. This
8045 intrinsic returns the executable address corresponding to <tt>tramp</tt>
8046 after performing the required machine specific adjustments.
8047 The pointer returned can then be <a href="#int_trampoline"> bitcast and
8048 executed</a>.
8049</p>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8050
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8051</div>
8052
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8053</div>
8054
Duncan Sands644f9172007-07-27 12:58:54 +0000[diff] [blame]8055<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8056<h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8057 <a name="int_memorymarkers">Memory Use Markers</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8058</h3>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8059
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8060<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8061
8062<p>This class of intrinsics exists to information about the lifetime of memory
8063 objects and ranges where variables are immutable.</p>
8064
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8065<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8066<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8067 <a name="int_lifetime_start">'<tt>llvm.lifetime.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8068</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8069
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8070<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8071
8072<h5>Syntax:</h5>
8073<pre>
8074 declare void @llvm.lifetime.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8075</pre>
8076
8077<h5>Overview:</h5>
8078<p>The '<tt>llvm.lifetime.start</tt>' intrinsic specifies the start of a memory
8079 object's lifetime.</p>
8080
8081<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8082<p>The first argument is a constant integer representing the size of the
8083 object, or -1 if it is variable sized. The second argument is a pointer to
8084 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8085
8086<h5>Semantics:</h5>
8087<p>This intrinsic indicates that before this point in the code, the value of the
8088 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
Nick Lewyckyd20fd592009-10-27 16:56:58 +0000[diff] [blame]8089 never be used and has an undefined value. A load from the pointer that
8090 precedes this intrinsic can be replaced with
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8091 <tt>'<a href="#undefvalues">undef</a>'</tt>.</p>
8092
8093</div>
8094
8095<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8096<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8097 <a name="int_lifetime_end">'<tt>llvm.lifetime.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8098</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8099
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8100<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8101
8102<h5>Syntax:</h5>
8103<pre>
8104 declare void @llvm.lifetime.end(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8105</pre>
8106
8107<h5>Overview:</h5>
8108<p>The '<tt>llvm.lifetime.end</tt>' intrinsic specifies the end of a memory
8109 object's lifetime.</p>
8110
8111<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8112<p>The first argument is a constant integer representing the size of the
8113 object, or -1 if it is variable sized. The second argument is a pointer to
8114 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8115
8116<h5>Semantics:</h5>
8117<p>This intrinsic indicates that after this point in the code, the value of the
8118 memory pointed to by <tt>ptr</tt> is dead. This means that it is known to
8119 never be used and has an undefined value. Any stores into the memory object
8120 following this intrinsic may be removed as dead.
8121
8122</div>
8123
8124<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8125<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8126 <a name="int_invariant_start">'<tt>llvm.invariant.start</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8127</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8128
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8129<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8130
8131<h5>Syntax:</h5>
8132<pre>
Nick Lewycky2965d3e2010-11-30 04:13:41 +0000[diff] [blame]8133 declare {}* @llvm.invariant.start(i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8134</pre>
8135
8136<h5>Overview:</h5>
8137<p>The '<tt>llvm.invariant.start</tt>' intrinsic specifies that the contents of
8138 a memory object will not change.</p>
8139
8140<h5>Arguments:</h5>
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8141<p>The first argument is a constant integer representing the size of the
8142 object, or -1 if it is variable sized. The second argument is a pointer to
8143 the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8144
8145<h5>Semantics:</h5>
8146<p>This intrinsic indicates that until an <tt>llvm.invariant.end</tt> that uses
8147 the return value, the referenced memory location is constant and
8148 unchanging.</p>
8149
8150</div>
8151
8152<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8153<h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8154 <a name="int_invariant_end">'<tt>llvm.invariant.end</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8155</h4>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8156
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8157<div>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8158
8159<h5>Syntax:</h5>
8160<pre>
8161 declare void @llvm.invariant.end({}* &lt;start&gt;, i64 &lt;size&gt;, i8* nocapture &lt;ptr&gt;)
8162</pre>
8163
8164<h5>Overview:</h5>
8165<p>The '<tt>llvm.invariant.end</tt>' intrinsic specifies that the contents of
8166 a memory object are mutable.</p>
8167
8168<h5>Arguments:</h5>
8169<p>The first argument is the matching <tt>llvm.invariant.start</tt> intrinsic.
Nick Lewycky9bc89042009-10-13 07:57:33 +0000[diff] [blame]8170 The second argument is a constant integer representing the size of the
8171 object, or -1 if it is variable sized and the third argument is a pointer
8172 to the object.</p>
Nick Lewycky6f7d8342009-10-13 07:03:23 +0000[diff] [blame]8173
8174<h5>Semantics:</h5>
8175<p>This intrinsic indicates that the memory is mutable again.</p>
8176
8177</div>
8178
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8179</div>
8180
Andrew Lenharth9b254ee2008-02-16 01:24:58 +0000[diff] [blame]8181<!-- ======================================================================= -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8182<h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8183 <a name="int_general">General Intrinsics</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8184</h3>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8185
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8186<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8187
8188<p>This class of intrinsics is designed to be generic and has no specific
8189 purpose.</p>
8190
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8191<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8192<h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8193 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8194</h4>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8195
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8196<div>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8197
8198<h5>Syntax:</h5>
8199<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8200 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]8201</pre>
8202
8203<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8204<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8205
8206<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8207<p>The first argument is a pointer to a value, the second is a pointer to a
8208 global string, the third is a pointer to a global string which is the source
8209 file name, and the last argument is the line number.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8210
8211<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8212<p>This intrinsic allows annotation of local variables with arbitrary strings.
8213 This can be useful for special purpose optimizations that want to look for
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8214 these annotations. These have no other defined use; they are ignored by code
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8215 generation and optimization.</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8216
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000[diff] [blame]8217</div>
8218
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8219<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8220<h4>
Tanya Lattner0186a652007-09-21 23:57:59 +0000[diff] [blame]8221 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8222</h4>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8223
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8224<div>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8225
8226<h5>Syntax:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8227<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
8228 any integer bit width.</p>
8229
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8230<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8231 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8232 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8233 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8234 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
8235 declare i256 @llvm.annotation.i256(i256 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt;)
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8236</pre>
8237
8238<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8239<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8240
8241<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8242<p>The first argument is an integer value (result of some expression), the
8243 second is a pointer to a global string, the third is a pointer to a global
8244 string which is the source file name, and the last argument is the line
8245 number. It returns the value of the first argument.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8246
8247<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8248<p>This intrinsic allows annotations to be put on arbitrary expressions with
8249 arbitrary strings. This can be useful for special purpose optimizations that
John Criswellf0d536a2011-08-19 16:57:55 +0000[diff] [blame]8250 want to look for these annotations. These have no other defined use; they
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8251 are ignored by code generation and optimization.</p>
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8252
Tanya Lattner293c0372007-09-21 22:59:12 +0000[diff] [blame]8253</div>
Jim Laskey2211f492007-03-14 19:31:19 +0000[diff] [blame]8254
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8255<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8256<h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8257 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8258</h4>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8259
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8260<div>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8261
8262<h5>Syntax:</h5>
8263<pre>
8264 declare void @llvm.trap()
8265</pre>
8266
8267<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8268<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8269
8270<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8271<p>None.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8272
8273<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8274<p>This intrinsics is lowered to the target dependent trap instruction. If the
8275 target does not have a trap instruction, this intrinsic will be lowered to
8276 the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8277
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000[diff] [blame]8278</div>
8279
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8280<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8281<h4>
Misha Brukman50de2b22008-11-22 23:55:29 +0000[diff] [blame]8282 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8283</h4>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8284
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8285<div>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8286
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8287<h5>Syntax:</h5>
8288<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8289 declare void @llvm.stackprotector(i8* &lt;guard&gt;, i8** &lt;slot&gt;)
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8290</pre>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8291
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8292<h5>Overview:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8293<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
8294 stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
8295 ensure that it is placed on the stack before local variables.</p>
8296
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8297<h5>Arguments:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8298<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
8299 arguments. The first argument is the value loaded from the stack
8300 guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
8301 that has enough space to hold the value of the guard.</p>
8302
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8303<h5>Semantics:</h5>
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8304<p>This intrinsic causes the prologue/epilogue inserter to force the position of
8305 the <tt>AllocaInst</tt> stack slot to be before local variables on the
8306 stack. This is to ensure that if a local variable on the stack is
8307 overwritten, it will destroy the value of the guard. When the function exits,
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8308 the guard on the stack is checked against the original guard. If they are
Bill Wendlingd9a66f72009-07-20 02:29:24 +0000[diff] [blame]8309 different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
8310 function.</p>
8311
Bill Wendling14313312008-11-19 05:56:17 +0000[diff] [blame]8312</div>
8313
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8314<!-- _______________________________________________________________________ -->
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8315<h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8316 <a name="int_objectsize">'<tt>llvm.objectsize</tt>' Intrinsic</a>
NAKAMURA Takumifc8d9302011-04-18 23:59:50 +0000[diff] [blame]8317</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8318
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8319<div>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8320
8321<h5>Syntax:</h5>
8322<pre>
Dan Gohmand6a6f612010-05-28 17:07:41 +0000[diff] [blame]8323 declare i32 @llvm.objectsize.i32(i8* &lt;object&gt;, i1 &lt;type&gt;)
8324 declare i64 @llvm.objectsize.i64(i8* &lt;object&gt;, i1 &lt;type&gt;)
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8325</pre>
8326
8327<h5>Overview:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8328<p>The <tt>llvm.objectsize</tt> intrinsic is designed to provide information to
8329 the optimizers to determine at compile time whether a) an operation (like
8330 memcpy) will overflow a buffer that corresponds to an object, or b) that a
8331 runtime check for overflow isn't necessary. An object in this context means
8332 an allocation of a specific class, structure, array, or other object.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8333
8334<h5>Arguments:</h5>
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8335<p>The <tt>llvm.objectsize</tt> intrinsic takes two arguments. The first
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8336 argument is a pointer to or into the <tt>object</tt>. The second argument
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8337 is a boolean 0 or 1. This argument determines whether you want the
8338 maximum (0) or minimum (1) bytes remaining. This needs to be a literal 0 or
Eric Christopher31e39bd2009-12-23 00:29:49 +0000[diff] [blame]8339 1, variables are not allowed.</p>
8340
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8341<h5>Semantics:</h5>
8342<p>The <tt>llvm.objectsize</tt> intrinsic is lowered to either a constant
Bill Wendling6bbe0912010-10-27 01:07:41 +0000[diff] [blame]8343 representing the size of the object concerned, or <tt>i32/i64 -1 or 0</tt>,
8344 depending on the <tt>type</tt> argument, if the size cannot be determined at
8345 compile time.</p>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8346
8347</div>
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8348<!-- _______________________________________________________________________ -->
8349<h4>
8350 <a name="int_expect">'<tt>llvm.expect</tt>' Intrinsic</a>
8351</h4>
Eric Christopher73484322009-11-30 08:03:53 +0000[diff] [blame]8352
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8353<div>
8354
8355<h5>Syntax:</h5>
8356<pre>
8357 declare i32 @llvm.expect.i32(i32 &lt;val&gt;, i32 &lt;expected_val&gt;)
8358 declare i64 @llvm.expect.i64(i64 &lt;val&gt;, i64 &lt;expected_val&gt;)
8359</pre>
8360
8361<h5>Overview:</h5>
8362<p>The <tt>llvm.expect</tt> intrinsic provides information about expected (the
8363 most probable) value of <tt>val</tt>, which can be used by optimizers.</p>
8364
8365<h5>Arguments:</h5>
8366<p>The <tt>llvm.expect</tt> intrinsic takes two arguments. The first
8367 argument is a value. The second argument is an expected value, this needs to
8368 be a constant value, variables are not allowed.</p>
8369
8370<h5>Semantics:</h5>
8371<p>This intrinsic is lowered to the <tt>val</tt>.</p>
NAKAMURA Takumiaa3d6242011-04-23 00:30:22 +0000[diff] [blame]8372</div>
8373
8374</div>
8375
Jakub Staszak5fef7922011-12-04 18:29:26 +0000[diff] [blame]8376</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8377<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +0000[diff] [blame]8378<hr>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8379<address>
8380 <a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8381 src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8382 <a href="http://validator.w3.org/check/referer"><img
Misha Brukman86242e12008-12-11 17:34:48 +0000[diff] [blame]8383 src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8384
8385 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
NAKAMURA Takumica46f5a2011-04-09 02:13:37 +0000[diff] [blame]8386 <a href="http://llvm.org/">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +0000[diff] [blame]8387 Last modified: $Date$
8388</address>
Chris Lattnerb8f816e2008-01-04 04:33:49 +0000[diff] [blame]8389
Misha Brukman76307852003-11-08 01:05:38 +0000[diff] [blame]8390</body>
8391</html>