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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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9 content="LLVM Assembly Language Reference Manual.">
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11</head>
Chris Lattner757528b0b2004-05-23 21:06:01 +000012
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Chris Lattner757528b0b2004-05-23 21:06:01 +000014
Chris Lattner48b383b02003-11-25 01:02:51 +000015<div class="doc_title"> LLVM Language Reference Manual </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +000016<ol>
Misha Brukman76307852003-11-08 01:05:38 +000017 <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 +000020 <li><a href="#highlevel">High Level Structure</a>
21 <ol>
22 <li><a href="#modulestructure">Module Structure</a></li>
Chris Lattnerd79749a2004-12-09 16:36:40 +000023 <li><a href="#linkage">Linkage Types</a></li>
Chris Lattner0132aff2005-05-06 22:57:40 +000024 <li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattnerbc088212009-01-11 20:53:49 +000025 <li><a href="#namedtypes">Named Types</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +000026 <li><a href="#globalvars">Global Variables</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +000027 <li><a href="#functionstructure">Functions</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +000028 <li><a href="#aliasstructure">Aliases</a></li>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +000029 <li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel9eb525d2008-09-26 23:51:19 +000030 <li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen71183b62007-12-10 03:18:06 +000031 <li><a href="#gc">Garbage Collector Names</a></li>
Chris Lattner91c15c42006-01-23 23:23:47 +000032 <li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
Reid Spencer50c723a2007-02-19 23:54:10 +000033 <li><a href="#datalayout">Data Layout</a></li>
Chris Lattner6af02f32004-12-09 16:11:40 +000034 </ol>
35 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +000036 <li><a href="#typesystem">Type System</a>
37 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +000038 <li><a href="#t_classifications">Type Classifications</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +000039 <li><a href="#t_primitive">Primitive Types</a>
Chris Lattner48b383b02003-11-25 01:02:51 +000040 <ol>
Chris Lattner7824d182008-01-04 04:32:38 +000041 <li><a href="#t_floating">Floating Point Types</a></li>
42 <li><a href="#t_void">Void Type</a></li>
43 <li><a href="#t_label">Label Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000044 </ol>
45 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +000046 <li><a href="#t_derived">Derived Types</a>
47 <ol>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +000048 <li><a href="#t_integer">Integer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000049 <li><a href="#t_array">Array Type</a></li>
Misha Brukman76307852003-11-08 01:05:38 +000050 <li><a href="#t_function">Function Type</a></li>
51 <li><a href="#t_pointer">Pointer Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000052 <li><a href="#t_struct">Structure Type</a></li>
Andrew Lenharth8df88e22006-12-08 17:13:00 +000053 <li><a href="#t_pstruct">Packed Structure Type</a></li>
Reid Spencer404a3252007-02-15 03:07:05 +000054 <li><a href="#t_vector">Vector Type</a></li>
Chris Lattner37b6b092005-04-25 17:34:15 +000055 <li><a href="#t_opaque">Opaque Type</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000056 </ol>
57 </li>
Chris Lattnercf7a5842009-02-02 07:32:36 +000058 <li><a href="#t_uprefs">Type Up-references</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000059 </ol>
60 </li>
Chris Lattner6af02f32004-12-09 16:11:40 +000061 <li><a href="#constants">Constants</a>
Chris Lattner74d3f822004-12-09 17:30:23 +000062 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +000063 <li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner361bfcd2009-02-28 18:32:25 +000064 <li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohmanef9462f2008-10-14 16:51:45 +000065 <li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
66 <li><a href="#undefvalues">Undefined Values</a></li>
67 <li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky49f89192009-04-04 07:22:01 +000068 <li><a href="#metadata">Embedded Metadata</a></li>
Chris Lattner74d3f822004-12-09 17:30:23 +000069 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +000070 </li>
Chris Lattner98f013c2006-01-25 23:47:57 +000071 <li><a href="#othervalues">Other Values</a>
72 <ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +000073 <li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Chris Lattner98f013c2006-01-25 23:47:57 +000074 </ol>
75 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +000076 <li><a href="#instref">Instruction Reference</a>
77 <ol>
78 <li><a href="#terminators">Terminator Instructions</a>
79 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +000080 <li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
81 <li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +000082 <li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
83 <li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000084 <li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
Chris Lattner08b7d5b2004-10-16 18:04:13 +000085 <li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000086 </ol>
87 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +000088 <li><a href="#binaryops">Binary Operations</a>
89 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +000090 <li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
91 <li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
92 <li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Reid Spencer7e80b0b2006-10-26 06:15:43 +000093 <li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
94 <li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
95 <li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
Reid Spencer7eb55b32006-11-02 01:53:59 +000096 <li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
97 <li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
98 <li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +000099 </ol>
100 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000101 <li><a href="#bitwiseops">Bitwise Binary Operations</a>
102 <ol>
Reid Spencer2ab01932007-02-02 13:57:07 +0000103 <li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
104 <li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
105 <li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000106 <li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000107 <li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
Misha Brukman76307852003-11-08 01:05:38 +0000108 <li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000109 </ol>
110 </li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000111 <li><a href="#vectorops">Vector Operations</a>
112 <ol>
113 <li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
114 <li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
115 <li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
Chris Lattnerce83bff2006-04-08 23:07:04 +0000116 </ol>
117 </li>
Dan Gohmanb9d66602008-05-12 23:51:09 +0000118 <li><a href="#aggregateops">Aggregate Operations</a>
119 <ol>
120 <li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
121 <li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
122 </ol>
123 </li>
Chris Lattner6ab66722006-08-15 00:45:58 +0000124 <li><a href="#memoryops">Memory Access and Addressing Operations</a>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000125 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000126 <li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
127 <li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
128 <li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
Robert Bocchino820bc75b2006-02-17 21:18:08 +0000129 <li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
130 <li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
131 <li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000132 </ol>
133 </li>
Reid Spencer97c5fa42006-11-08 01:18:52 +0000134 <li><a href="#convertops">Conversion Operations</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000135 <ol>
136 <li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
137 <li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
138 <li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
139 <li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
140 <li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
Reid Spencer51b07252006-11-09 23:03:26 +0000141 <li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
142 <li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
143 <li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
144 <li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
Reid Spencerb7344ff2006-11-11 21:00:47 +0000145 <li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
146 <li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
Reid Spencer5b950642006-11-11 23:08:07 +0000147 <li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
Reid Spencer59b6b7d2006-11-08 01:11:31 +0000148 </ol>
Dan Gohmanef9462f2008-10-14 16:51:45 +0000149 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000150 <li><a href="#otherops">Other Operations</a>
151 <ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +0000152 <li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
153 <li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
Nate Begemand2195702008-05-12 19:01:56 +0000154 <li><a href="#i_vicmp">'<tt>vicmp</tt>' Instruction</a></li>
155 <li><a href="#i_vfcmp">'<tt>vfcmp</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000156 <li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
Chris Lattnerb53c28d2004-03-12 05:50:16 +0000157 <li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000158 <li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
Chris Lattner33337472006-01-13 23:26:01 +0000159 <li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000160 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000161 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000162 </ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000163 </li>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000164 <li><a href="#intrinsics">Intrinsic Functions</a>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +0000165 <ol>
Chris Lattner48b383b02003-11-25 01:02:51 +0000166 <li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
167 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000168 <li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
169 <li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
170 <li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000171 </ol>
172 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000173 <li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
174 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000175 <li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
176 <li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
177 <li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000178 </ol>
179 </li>
Chris Lattner3649c3a2004-02-14 04:08:35 +0000180 <li><a href="#int_codegen">Code Generator Intrinsics</a>
181 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000182 <li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
183 <li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
184 <li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
185 <li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
186 <li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
187 <li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
188 <li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
John Criswellaa1c3c12004-04-09 16:43:20 +0000189 </ol>
190 </li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000191 <li><a href="#int_libc">Standard C Library Intrinsics</a>
192 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000193 <li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
194 <li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
195 <li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
196 <li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
197 <li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohmanb6324c12007-10-15 20:30:11 +0000198 <li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
199 <li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
200 <li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Chris Lattnerfee11462004-02-12 17:01:32 +0000201 </ol>
202 </li>
Nate Begeman0f223bb2006-01-13 23:26:38 +0000203 <li><a href="#int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000204 <ol>
Reid Spencer96a5f022007-04-04 02:42:35 +0000205 <li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
Chris Lattnerb748c672006-01-16 22:34:14 +0000206 <li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
207 <li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
208 <li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Reid Spencer5bf54c82007-04-11 23:23:49 +0000209 <li><a href="#int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic </a></li>
210 <li><a href="#int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic </a></li>
Andrew Lenharth1d463522005-05-03 18:01:48 +0000211 </ol>
212 </li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000213 <li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
214 <ol>
Bill Wendlingfd2bd722009-02-08 04:04:40 +0000215 <li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
216 <li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
217 <li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
218 <li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
219 <li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingb9a73272009-02-08 23:00:09 +0000220 <li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendlingf4d70622009-02-08 01:40:31 +0000221 </ol>
222 </li>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000223 <li><a href="#int_debugger">Debugger intrinsics</a></li>
Jim Laskey2211f492007-03-14 19:31:19 +0000224 <li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands86e01192007-09-11 14:10:23 +0000225 <li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +0000226 <ol>
227 <li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands644f9172007-07-27 12:58:54 +0000228 </ol>
229 </li>
Bill Wendlingf85850f2008-11-18 22:10:53 +0000230 <li><a href="#int_atomics">Atomic intrinsics</a>
231 <ol>
232 <li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
233 <li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
234 <li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
235 <li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
236 <li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
237 <li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
238 <li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
239 <li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
240 <li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
241 <li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
242 <li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
243 <li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
244 <li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
245 </ol>
246 </li>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000247 <li><a href="#int_general">General intrinsics</a>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000248 <ol>
Reid Spencer5b2cb0f2007-07-20 19:59:11 +0000249 <li><a href="#int_var_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000250 '<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000251 <li><a href="#int_annotation">
Bill Wendling14313312008-11-19 05:56:17 +0000252 '<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +0000253 <li><a href="#int_trap">
Bill Wendling14313312008-11-19 05:56:17 +0000254 '<tt>llvm.trap</tt>' Intrinsic</a></li>
255 <li><a href="#int_stackprotector">
256 '<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattner293c0372007-09-21 22:59:12 +0000257 </ol>
Tanya Lattnercb1b9602007-06-15 20:50:54 +0000258 </li>
Chris Lattner48b383b02003-11-25 01:02:51 +0000259 </ol>
260 </li>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000261</ol>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000262
263<div class="doc_author">
264 <p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
265 and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
Misha Brukman76307852003-11-08 01:05:38 +0000266</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000267
Chris Lattner2f7c9632001-06-06 20:29:01 +0000268<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000269<div class="doc_section"> <a name="abstract">Abstract </a></div>
270<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000271
Misha Brukman76307852003-11-08 01:05:38 +0000272<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +0000273<p>This document is a reference manual for the LLVM assembly language.
Bill Wendling6e03f9a2008-08-05 22:29:16 +0000274LLVM is a Static Single Assignment (SSA) based representation that provides
Chris Lattner67c37d12008-08-05 18:29:16 +0000275type safety, low-level operations, flexibility, and the capability of
276representing 'all' high-level languages cleanly. It is the common code
Chris Lattner48b383b02003-11-25 01:02:51 +0000277representation used throughout all phases of the LLVM compilation
278strategy.</p>
Misha Brukman76307852003-11-08 01:05:38 +0000279</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000280
Chris Lattner2f7c9632001-06-06 20:29:01 +0000281<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000282<div class="doc_section"> <a name="introduction">Introduction</a> </div>
283<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000284
Misha Brukman76307852003-11-08 01:05:38 +0000285<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000286
Chris Lattner48b383b02003-11-25 01:02:51 +0000287<p>The LLVM code representation is designed to be used in three
Gabor Greifa54634a2007-07-06 22:07:22 +0000288different forms: as an in-memory compiler IR, as an on-disk bitcode
Chris Lattner48b383b02003-11-25 01:02:51 +0000289representation (suitable for fast loading by a Just-In-Time compiler),
290and as a human readable assembly language representation. This allows
291LLVM to provide a powerful intermediate representation for efficient
292compiler transformations and analysis, while providing a natural means
293to debug and visualize the transformations. The three different forms
294of LLVM are all equivalent. This document describes the human readable
295representation and notation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000296
John Criswell4a3327e2005-05-13 22:25:59 +0000297<p>The LLVM representation aims to be light-weight and low-level
Chris Lattner48b383b02003-11-25 01:02:51 +0000298while being expressive, typed, and extensible at the same time. It
299aims to be a "universal IR" of sorts, by being at a low enough level
300that high-level ideas may be cleanly mapped to it (similar to how
301microprocessors are "universal IR's", allowing many source languages to
302be mapped to them). By providing type information, LLVM can be used as
303the target of optimizations: for example, through pointer analysis, it
304can be proven that a C automatic variable is never accessed outside of
305the current function... allowing it to be promoted to a simple SSA
306value instead of a memory location.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000307
Misha Brukman76307852003-11-08 01:05:38 +0000308</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000309
Chris Lattner2f7c9632001-06-06 20:29:01 +0000310<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000311<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000312
Misha Brukman76307852003-11-08 01:05:38 +0000313<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000314
Chris Lattner48b383b02003-11-25 01:02:51 +0000315<p>It is important to note that this document describes 'well formed'
316LLVM assembly language. There is a difference between what the parser
317accepts and what is considered 'well formed'. For example, the
318following instruction is syntactically okay, but not well formed:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000319
Bill Wendling3716c5d2007-05-29 09:04:49 +0000320<div class="doc_code">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000321<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000322%x = <a href="#i_add">add</a> i32 1, %x
Chris Lattner757528b0b2004-05-23 21:06:01 +0000323</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000324</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000325
Chris Lattner48b383b02003-11-25 01:02:51 +0000326<p>...because the definition of <tt>%x</tt> does not dominate all of
327its uses. The LLVM infrastructure provides a verification pass that may
328be used to verify that an LLVM module is well formed. This pass is
John Criswell4a3327e2005-05-13 22:25:59 +0000329automatically run by the parser after parsing input assembly and by
Gabor Greifa54634a2007-07-06 22:07:22 +0000330the optimizer before it outputs bitcode. The violations pointed out
Chris Lattner48b383b02003-11-25 01:02:51 +0000331by the verifier pass indicate bugs in transformation passes or input to
332the parser.</p>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000333</div>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000334
Chris Lattner87a3dbe2007-10-03 17:34:29 +0000335<!-- Describe the typesetting conventions here. -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000336
Chris Lattner2f7c9632001-06-06 20:29:01 +0000337<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +0000338<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
Chris Lattner2f7c9632001-06-06 20:29:01 +0000339<!-- *********************************************************************** -->
Chris Lattner757528b0b2004-05-23 21:06:01 +0000340
Misha Brukman76307852003-11-08 01:05:38 +0000341<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +0000342
Reid Spencerb23b65f2007-08-07 14:34:28 +0000343 <p>LLVM identifiers come in two basic types: global and local. Global
344 identifiers (functions, global variables) begin with the @ character. Local
345 identifiers (register names, types) begin with the % character. Additionally,
Dan Gohmanef9462f2008-10-14 16:51:45 +0000346 there are three different formats for identifiers, for different purposes:</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +0000347
Chris Lattner2f7c9632001-06-06 20:29:01 +0000348<ol>
Reid Spencerb23b65f2007-08-07 14:34:28 +0000349 <li>Named values are represented as a string of characters with their prefix.
350 For example, %foo, @DivisionByZero, %a.really.long.identifier. The actual
351 regular expression used is '<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000352 Identifiers which require other characters in their names can be surrounded
Daniel Dunbar0f8155a2008-10-14 23:51:43 +0000353 with quotes. Special characters may be escaped using "\xx" where xx is the
354 ASCII code for the character in hexadecimal. In this way, any character can
355 be used in a name value, even quotes themselves.
Chris Lattnerd79749a2004-12-09 16:36:40 +0000356
Reid Spencerb23b65f2007-08-07 14:34:28 +0000357 <li>Unnamed values are represented as an unsigned numeric value with their
358 prefix. For example, %12, @2, %44.</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000359
Reid Spencer8f08d802004-12-09 18:02:53 +0000360 <li>Constants, which are described in a <a href="#constants">section about
361 constants</a>, below.</li>
Misha Brukman76307852003-11-08 01:05:38 +0000362</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000363
Reid Spencerb23b65f2007-08-07 14:34:28 +0000364<p>LLVM requires that values start with a prefix for two reasons: Compilers
Chris Lattnerd79749a2004-12-09 16:36:40 +0000365don't need to worry about name clashes with reserved words, and the set of
366reserved words may be expanded in the future without penalty. Additionally,
367unnamed identifiers allow a compiler to quickly come up with a temporary
368variable without having to avoid symbol table conflicts.</p>
369
Chris Lattner48b383b02003-11-25 01:02:51 +0000370<p>Reserved words in LLVM are very similar to reserved words in other
Reid Spencer5b950642006-11-11 23:08:07 +0000371languages. There are keywords for different opcodes
372('<tt><a href="#i_add">add</a></tt>',
373 '<tt><a href="#i_bitcast">bitcast</a></tt>',
374 '<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names ('<tt><a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000375href="#t_void">void</a></tt>', '<tt><a href="#t_primitive">i32</a></tt>', etc...),
Chris Lattnerd79749a2004-12-09 16:36:40 +0000376and others. These reserved words cannot conflict with variable names, because
Reid Spencerb23b65f2007-08-07 14:34:28 +0000377none of them start with a prefix character ('%' or '@').</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000378
379<p>Here is an example of LLVM code to multiply the integer variable
380'<tt>%X</tt>' by 8:</p>
381
Misha Brukman76307852003-11-08 01:05:38 +0000382<p>The easy way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000383
Bill Wendling3716c5d2007-05-29 09:04:49 +0000384<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000385<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000386%result = <a href="#i_mul">mul</a> i32 %X, 8
Chris Lattnerd79749a2004-12-09 16:36:40 +0000387</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000388</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000389
Misha Brukman76307852003-11-08 01:05:38 +0000390<p>After strength reduction:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000391
Bill Wendling3716c5d2007-05-29 09:04:49 +0000392<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000393<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000394%result = <a href="#i_shl">shl</a> i32 %X, i8 3
Chris Lattnerd79749a2004-12-09 16:36:40 +0000395</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000396</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000397
Misha Brukman76307852003-11-08 01:05:38 +0000398<p>And the hard way:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000399
Bill Wendling3716c5d2007-05-29 09:04:49 +0000400<div class="doc_code">
Chris Lattnerd79749a2004-12-09 16:36:40 +0000401<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000402<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
403<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
404%result = <a href="#i_add">add</a> i32 %1, %1
Chris Lattnerd79749a2004-12-09 16:36:40 +0000405</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000406</div>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000407
Chris Lattner48b383b02003-11-25 01:02:51 +0000408<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several
409important lexical features of LLVM:</p>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000410
Chris Lattner2f7c9632001-06-06 20:29:01 +0000411<ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000412
413 <li>Comments are delimited with a '<tt>;</tt>' and go until the end of
414 line.</li>
415
416 <li>Unnamed temporaries are created when the result of a computation is not
417 assigned to a named value.</li>
418
Misha Brukman76307852003-11-08 01:05:38 +0000419 <li>Unnamed temporaries are numbered sequentially</li>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000420
Misha Brukman76307852003-11-08 01:05:38 +0000421</ol>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000422
John Criswell02fdc6f2005-05-12 16:52:32 +0000423<p>...and it also shows a convention that we follow in this document. When
Chris Lattnerd79749a2004-12-09 16:36:40 +0000424demonstrating instructions, we will follow an instruction with a comment that
425defines the type and name of value produced. Comments are shown in italic
426text.</p>
427
Misha Brukman76307852003-11-08 01:05:38 +0000428</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000429
430<!-- *********************************************************************** -->
431<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
432<!-- *********************************************************************** -->
433
434<!-- ======================================================================= -->
435<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
436</div>
437
438<div class="doc_text">
439
440<p>LLVM programs are composed of "Module"s, each of which is a
441translation unit of the input programs. Each module consists of
442functions, global variables, and symbol table entries. Modules may be
443combined together with the LLVM linker, which merges function (and
444global variable) definitions, resolves forward declarations, and merges
445symbol table entries. Here is an example of the "hello world" module:</p>
446
Bill Wendling3716c5d2007-05-29 09:04:49 +0000447<div class="doc_code">
Chris Lattner6af02f32004-12-09 16:11:40 +0000448<pre><i>; Declare the string constant as a global constant...</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000449<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
450 href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000451
452<i>; External declaration of the puts function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000453<a href="#functionstructure">declare</a> i32 @puts(i8 *) <i>; i32(i8 *)* </i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000454
455<i>; Definition of main function</i>
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000456define i32 @main() { <i>; i32()* </i>
Dan Gohman623806e2009-01-04 23:44:43 +0000457 <i>; Convert [13 x i8]* to i8 *...</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000458 %cast210 = <a
Dan Gohman623806e2009-01-04 23:44:43 +0000459 href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000460
461 <i>; Call puts function to write out the string to stdout...</i>
462 <a
Chris Lattner2b0bf4f2007-06-12 17:00:26 +0000463 href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Chris Lattner6af02f32004-12-09 16:11:40 +0000464 <a
Bill Wendling3716c5d2007-05-29 09:04:49 +0000465 href="#i_ret">ret</a> i32 0<br>}<br>
466</pre>
467</div>
Chris Lattner6af02f32004-12-09 16:11:40 +0000468
469<p>This example is made up of a <a href="#globalvars">global variable</a>
470named "<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>"
471function, and a <a href="#functionstructure">function definition</a>
472for "<tt>main</tt>".</p>
473
Chris Lattnerd79749a2004-12-09 16:36:40 +0000474<p>In general, a module is made up of a list of global values,
475where both functions and global variables are global values. Global values are
476represented by a pointer to a memory location (in this case, a pointer to an
477array of char, and a pointer to a function), and have one of the following <a
478href="#linkage">linkage types</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000479
Chris Lattnerd79749a2004-12-09 16:36:40 +0000480</div>
481
482<!-- ======================================================================= -->
483<div class="doc_subsection">
484 <a name="linkage">Linkage Types</a>
485</div>
486
487<div class="doc_text">
488
489<p>
490All Global Variables and Functions have one of the following types of linkage:
491</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000492
493<dl>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000494
Rafael Espindola6de96a12009-01-15 20:18:42 +0000495 <dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
496
497 <dd>Global values with private linkage are only directly accessible by
498 objects in the current module. In particular, linking code into a module with
499 an private global value may cause the private to be renamed as necessary to
500 avoid collisions. Because the symbol is private to the module, all
501 references can be updated. This doesn't show up in any symbol table in the
502 object file.
503 </dd>
504
Dale Johannesen4188aad2008-05-23 23:13:41 +0000505 <dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000506
Duncan Sands35e43c12009-01-16 09:29:46 +0000507 <dd> Similar to private, but the value shows as a local symbol (STB_LOCAL in
Rafael Espindola6de96a12009-01-15 20:18:42 +0000508 the case of ELF) in the object file. This corresponds to the notion of the
Chris Lattnere20b4702007-01-14 06:51:48 +0000509 '<tt>static</tt>' keyword in C.
Chris Lattner6af02f32004-12-09 16:11:40 +0000510 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000511
Chris Lattner184f1be2009-04-13 05:44:34 +0000512 <dt><tt><b><a name="available_externally">available_externally</a></b></tt>:
513 </dt>
514
515 <dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
516 into the object file corresponding to the LLVM module. They exist to
517 allow inlining and other optimizations to take place given knowledge of the
518 definition of the global, which is known to be somewhere outside the module.
519 Globals with <tt>available_externally</tt> linkage are allowed to be discarded
520 at will, and are otherwise the same as <tt>linkonce_odr</tt>. This linkage
521 type is only allowed on definitions, not declarations.</dd>
522
Chris Lattner6af02f32004-12-09 16:11:40 +0000523 <dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000524
Chris Lattnere20b4702007-01-14 06:51:48 +0000525 <dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
526 the same name when linkage occurs. This is typically used to implement
527 inline functions, templates, or other code which must be generated in each
528 translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
529 allowed to be discarded.
Chris Lattner6af02f32004-12-09 16:11:40 +0000530 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000531
Dale Johannesen4188aad2008-05-23 23:13:41 +0000532 <dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
533
534 <dd>"<tt>common</tt>" linkage is exactly the same as <tt>linkonce</tt>
535 linkage, except that unreferenced <tt>common</tt> globals may not be
536 discarded. This is used for globals that may be emitted in multiple
537 translation units, but that are not guaranteed to be emitted into every
538 translation unit that uses them. One example of this is tentative
539 definitions in C, such as "<tt>int X;</tt>" at global scope.
540 </dd>
541
Chris Lattner6af02f32004-12-09 16:11:40 +0000542 <dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000543
Dale Johannesen4188aad2008-05-23 23:13:41 +0000544 <dd>"<tt>weak</tt>" linkage is the same as <tt>common</tt> linkage, except
545 that some targets may choose to emit different assembly sequences for them
546 for target-dependent reasons. This is used for globals that are declared
547 "weak" in C source code.
Chris Lattner6af02f32004-12-09 16:11:40 +0000548 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000549
Chris Lattner6af02f32004-12-09 16:11:40 +0000550 <dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000551
552 <dd>"<tt>appending</tt>" linkage may only be applied to global variables of
553 pointer to array type. When two global variables with appending linkage are
554 linked together, the two global arrays are appended together. This is the
555 LLVM, typesafe, equivalent of having the system linker append together
556 "sections" with identical names when .o files are linked.
Chris Lattner6af02f32004-12-09 16:11:40 +0000557 </dd>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000558
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000559 <dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000560
Chris Lattner67c37d12008-08-05 18:29:16 +0000561 <dd>The semantics of this linkage follow the ELF object file model: the
562 symbol is weak until linked, if not linked, the symbol becomes null instead
563 of being an undefined reference.
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000564 </dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000565
Duncan Sands12da8ce2009-03-07 15:45:40 +0000566 <dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000567 <dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Chris Lattner184f1be2009-04-13 05:44:34 +0000568 <dd>Some languages allow differing globals to be merged, such as two
Duncan Sands12da8ce2009-03-07 15:45:40 +0000569 functions with different semantics. Other languages, such as <tt>C++</tt>,
570 ensure that only equivalent globals are ever merged (the "one definition
Chris Lattner184f1be2009-04-13 05:44:34 +0000571 rule" - "ODR"). Such languages can use the <tt>linkonce_odr</tt>
Duncan Sands4581beb2009-03-11 20:14:15 +0000572 and <tt>weak_odr</tt> linkage types to indicate that the global will only
573 be merged with equivalent globals. These linkage types are otherwise the
574 same as their non-<tt>odr</tt> versions.
Duncan Sands12da8ce2009-03-07 15:45:40 +0000575 </dd>
576
Chris Lattner6af02f32004-12-09 16:11:40 +0000577 <dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Chris Lattnerd79749a2004-12-09 16:36:40 +0000578
579 <dd>If none of the above identifiers are used, the global is externally
580 visible, meaning that it participates in linkage and can be used to resolve
581 external symbol references.
Chris Lattner6af02f32004-12-09 16:11:40 +0000582 </dd>
Reid Spencer7972c472007-04-11 23:49:50 +0000583</dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000584
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000585 <p>
586 The next two types of linkage are targeted for Microsoft Windows platform
587 only. They are designed to support importing (exporting) symbols from (to)
Chris Lattner67c37d12008-08-05 18:29:16 +0000588 DLLs (Dynamic Link Libraries).
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000589 </p>
590
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000591 <dl>
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000592 <dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
593
594 <dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
595 or variable via a global pointer to a pointer that is set up by the DLL
596 exporting the symbol. On Microsoft Windows targets, the pointer name is
Dan Gohman33a9cef2009-01-12 21:35:55 +0000597 formed by combining <code>__imp_</code> and the function or variable name.
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000598 </dd>
599
600 <dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
601
602 <dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
603 pointer to a pointer in a DLL, so that it can be referenced with the
604 <tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
Dan Gohman33a9cef2009-01-12 21:35:55 +0000605 name is formed by combining <code>__imp_</code> and the function or variable
Anton Korobeynikovd61d39e2006-09-14 18:23:27 +0000606 name.
607 </dd>
608
Chris Lattner6af02f32004-12-09 16:11:40 +0000609</dl>
610
Dan Gohman8ef44982008-11-24 17:18:39 +0000611<p>For example, since the "<tt>.LC0</tt>"
Chris Lattner6af02f32004-12-09 16:11:40 +0000612variable is defined to be internal, if another module defined a "<tt>.LC0</tt>"
613variable and was linked with this one, one of the two would be renamed,
614preventing a collision. Since "<tt>main</tt>" and "<tt>puts</tt>" are
615external (i.e., lacking any linkage declarations), they are accessible
Reid Spencer92c671e2007-01-05 00:59:10 +0000616outside of the current module.</p>
617<p>It is illegal for a function <i>declaration</i>
Duncan Sandse2881052009-03-11 08:08:06 +0000618to have any linkage type other than "externally visible", <tt>dllimport</tt>
619or <tt>extern_weak</tt>.</p>
Duncan Sands12da8ce2009-03-07 15:45:40 +0000620<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
621or <tt>weak_odr</tt> linkages.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000622</div>
623
624<!-- ======================================================================= -->
625<div class="doc_subsection">
Chris Lattner0132aff2005-05-06 22:57:40 +0000626 <a name="callingconv">Calling Conventions</a>
627</div>
628
629<div class="doc_text">
630
631<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
632and <a href="#i_invoke">invokes</a> can all have an optional calling convention
633specified for the call. The calling convention of any pair of dynamic
634caller/callee must match, or the behavior of the program is undefined. The
635following calling conventions are supported by LLVM, and more may be added in
636the future:</p>
637
638<dl>
639 <dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
640
641 <dd>This calling convention (the default if no other calling convention is
642 specified) matches the target C calling conventions. This calling convention
John Criswell02fdc6f2005-05-12 16:52:32 +0000643 supports varargs function calls and tolerates some mismatch in the declared
Reid Spencer72ba4992006-12-31 21:30:18 +0000644 prototype and implemented declaration of the function (as does normal C).
Chris Lattner0132aff2005-05-06 22:57:40 +0000645 </dd>
646
647 <dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
648
649 <dd>This calling convention attempts to make calls as fast as possible
650 (e.g. by passing things in registers). This calling convention allows the
651 target to use whatever tricks it wants to produce fast code for the target,
Chris Lattner67c37d12008-08-05 18:29:16 +0000652 without having to conform to an externally specified ABI (Application Binary
653 Interface). Implementations of this convention should allow arbitrary
Arnold Schwaighofer2c6b8882008-05-14 09:17:12 +0000654 <a href="CodeGenerator.html#tailcallopt">tail call optimization</a> to be
655 supported. This calling convention does not support varargs and requires the
656 prototype of all callees to exactly match the prototype of the function
657 definition.
Chris Lattner0132aff2005-05-06 22:57:40 +0000658 </dd>
659
660 <dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
661
662 <dd>This calling convention attempts to make code in the caller as efficient
663 as possible under the assumption that the call is not commonly executed. As
664 such, these calls often preserve all registers so that the call does not break
665 any live ranges in the caller side. This calling convention does not support
666 varargs and requires the prototype of all callees to exactly match the
667 prototype of the function definition.
668 </dd>
669
Chris Lattner573f64e2005-05-07 01:46:40 +0000670 <dt><b>"<tt>cc &lt;<em>n</em>&gt;</tt>" - Numbered convention</b>:</dt>
Chris Lattner0132aff2005-05-06 22:57:40 +0000671
672 <dd>Any calling convention may be specified by number, allowing
673 target-specific calling conventions to be used. Target specific calling
674 conventions start at 64.
675 </dd>
Chris Lattner573f64e2005-05-07 01:46:40 +0000676</dl>
Chris Lattner0132aff2005-05-06 22:57:40 +0000677
678<p>More calling conventions can be added/defined on an as-needed basis, to
679support pascal conventions or any other well-known target-independent
680convention.</p>
681
682</div>
683
684<!-- ======================================================================= -->
685<div class="doc_subsection">
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000686 <a name="visibility">Visibility Styles</a>
687</div>
688
689<div class="doc_text">
690
691<p>
692All Global Variables and Functions have one of the following visibility styles:
693</p>
694
695<dl>
696 <dt><b>"<tt>default</tt>" - Default style</b>:</dt>
697
Chris Lattner67c37d12008-08-05 18:29:16 +0000698 <dd>On targets that use the ELF object file format, default visibility means
699 that the declaration is visible to other
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000700 modules and, in shared libraries, means that the declared entity may be
701 overridden. On Darwin, default visibility means that the declaration is
702 visible to other modules. Default visibility corresponds to "external
703 linkage" in the language.
704 </dd>
705
706 <dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
707
708 <dd>Two declarations of an object with hidden visibility refer to the same
709 object if they are in the same shared object. Usually, hidden visibility
710 indicates that the symbol will not be placed into the dynamic symbol table,
711 so no other module (executable or shared library) can reference it
712 directly.
713 </dd>
714
Anton Korobeynikov39f3cff2007-04-29 18:35:00 +0000715 <dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
716
717 <dd>On ELF, protected visibility indicates that the symbol will be placed in
718 the dynamic symbol table, but that references within the defining module will
719 bind to the local symbol. That is, the symbol cannot be overridden by another
720 module.
721 </dd>
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000722</dl>
723
724</div>
725
726<!-- ======================================================================= -->
727<div class="doc_subsection">
Chris Lattnerbc088212009-01-11 20:53:49 +0000728 <a name="namedtypes">Named Types</a>
729</div>
730
731<div class="doc_text">
732
733<p>LLVM IR allows you to specify name aliases for certain types. This can make
734it easier to read the IR and make the IR more condensed (particularly when
735recursive types are involved). An example of a name specification is:
736</p>
737
738<div class="doc_code">
739<pre>
740%mytype = type { %mytype*, i32 }
741</pre>
742</div>
743
744<p>You may give a name to any <a href="#typesystem">type</a> except "<a
745href="t_void">void</a>". Type name aliases may be used anywhere a type is
746expected with the syntax "%mytype".</p>
747
748<p>Note that type names are aliases for the structural type that they indicate,
749and that you can therefore specify multiple names for the same type. This often
750leads to confusing behavior when dumping out a .ll file. Since LLVM IR uses
751structural typing, the name is not part of the type. When printing out LLVM IR,
752the printer will pick <em>one name</em> to render all types of a particular
753shape. This means that if you have code where two different source types end up
754having the same LLVM type, that the dumper will sometimes print the "wrong" or
755unexpected type. This is an important design point and isn't going to
756change.</p>
757
758</div>
759
Chris Lattnerbc088212009-01-11 20:53:49 +0000760<!-- ======================================================================= -->
761<div class="doc_subsection">
Chris Lattner6af02f32004-12-09 16:11:40 +0000762 <a name="globalvars">Global Variables</a>
763</div>
764
765<div class="doc_text">
766
Chris Lattner5d5aede2005-02-12 19:30:21 +0000767<p>Global variables define regions of memory allocated at compilation time
Chris Lattner662c8722005-11-12 00:45:07 +0000768instead of run-time. Global variables may optionally be initialized, may have
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000769an explicit section to be placed in, and may have an optional explicit alignment
770specified. A variable may be defined as "thread_local", which means that it
771will not be shared by threads (each thread will have a separated copy of the
772variable). A variable may be defined as a global "constant," which indicates
773that the contents of the variable will <b>never</b> be modified (enabling better
Chris Lattner5d5aede2005-02-12 19:30:21 +0000774optimization, allowing the global data to be placed in the read-only section of
775an executable, etc). Note that variables that need runtime initialization
John Criswell4c0cf7f2005-10-24 16:17:18 +0000776cannot be marked "constant" as there is a store to the variable.</p>
Chris Lattner5d5aede2005-02-12 19:30:21 +0000777
778<p>
779LLVM explicitly allows <em>declarations</em> of global variables to be marked
780constant, even if the final definition of the global is not. This capability
781can be used to enable slightly better optimization of the program, but requires
782the language definition to guarantee that optimizations based on the
783'constantness' are valid for the translation units that do not include the
784definition.
785</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000786
787<p>As SSA values, global variables define pointer values that are in
788scope (i.e. they dominate) all basic blocks in the program. Global
789variables always define a pointer to their "content" type because they
790describe a region of memory, and all memory objects in LLVM are
791accessed through pointers.</p>
792
Christopher Lamb308121c2007-12-11 09:31:00 +0000793<p>A global variable may be declared to reside in a target-specifc numbered
794address space. For targets that support them, address spaces may affect how
795optimizations are performed and/or what target instructions are used to access
Christopher Lamb25f50762007-12-12 08:44:39 +0000796the variable. The default address space is zero. The address space qualifier
797must precede any other attributes.</p>
Christopher Lamb308121c2007-12-11 09:31:00 +0000798
Chris Lattner662c8722005-11-12 00:45:07 +0000799<p>LLVM allows an explicit section to be specified for globals. If the target
800supports it, it will emit globals to the section specified.</p>
801
Chris Lattner54611b42005-11-06 08:02:57 +0000802<p>An explicit alignment may be specified for a global. If not present, or if
803the alignment is set to zero, the alignment of the global is set by the target
804to whatever it feels convenient. If an explicit alignment is specified, the
805global is forced to have at least that much alignment. All alignments must be
806a power of 2.</p>
807
Christopher Lamb308121c2007-12-11 09:31:00 +0000808<p>For example, the following defines a global in a numbered address space with
809an initializer, section, and alignment:</p>
Chris Lattner5760c502007-01-14 00:27:09 +0000810
Bill Wendling3716c5d2007-05-29 09:04:49 +0000811<div class="doc_code">
Chris Lattner5760c502007-01-14 00:27:09 +0000812<pre>
Dan Gohmanaaa679b2009-01-11 00:40:00 +0000813@G = addrspace(5) constant float 1.0, section "foo", align 4
Chris Lattner5760c502007-01-14 00:27:09 +0000814</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000815</div>
Chris Lattner5760c502007-01-14 00:27:09 +0000816
Chris Lattner6af02f32004-12-09 16:11:40 +0000817</div>
818
819
820<!-- ======================================================================= -->
821<div class="doc_subsection">
822 <a name="functionstructure">Functions</a>
823</div>
824
825<div class="doc_text">
826
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000827<p>LLVM function definitions consist of the "<tt>define</tt>" keyord,
828an optional <a href="#linkage">linkage type</a>, an optional
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000829<a href="#visibility">visibility style</a>, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000830<a href="#callingconv">calling convention</a>, a return type, an optional
831<a href="#paramattrs">parameter attribute</a> for the return type, a function
832name, a (possibly empty) argument list (each with optional
Devang Patel7e9b05e2008-10-06 18:50:38 +0000833<a href="#paramattrs">parameter attributes</a>), optional
834<a href="#fnattrs">function attributes</a>, an optional section,
835an optional alignment, an optional <a href="#gc">garbage collector name</a>,
Chris Lattnercbc4d2a2008-10-04 18:10:21 +0000836an opening curly brace, a list of basic blocks, and a closing curly brace.
Anton Korobeynikovc7f9f3d2007-01-23 12:35:46 +0000837
838LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
839optional <a href="#linkage">linkage type</a>, an optional
840<a href="#visibility">visibility style</a>, an optional
841<a href="#callingconv">calling convention</a>, a return type, an optional
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000842<a href="#paramattrs">parameter attribute</a> for the return type, a function
Gordon Henriksen71183b62007-12-10 03:18:06 +0000843name, a possibly empty list of arguments, an optional alignment, and an optional
Gordon Henriksendc5cafb2007-12-10 03:30:21 +0000844<a href="#gc">garbage collector name</a>.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +0000845
Chris Lattner67c37d12008-08-05 18:29:16 +0000846<p>A function definition contains a list of basic blocks, forming the CFG
847(Control Flow Graph) for
Chris Lattner6af02f32004-12-09 16:11:40 +0000848the function. Each basic block may optionally start with a label (giving the
849basic block a symbol table entry), contains a list of instructions, and ends
850with a <a href="#terminators">terminator</a> instruction (such as a branch or
851function return).</p>
852
Chris Lattnera59fb102007-06-08 16:52:14 +0000853<p>The first basic block in a function is special in two ways: it is immediately
Chris Lattner6af02f32004-12-09 16:11:40 +0000854executed on entrance to the function, and it is not allowed to have predecessor
855basic blocks (i.e. there can not be any branches to the entry block of a
856function). Because the block can have no predecessors, it also cannot have any
857<a href="#i_phi">PHI nodes</a>.</p>
858
Chris Lattner662c8722005-11-12 00:45:07 +0000859<p>LLVM allows an explicit section to be specified for functions. If the target
860supports it, it will emit functions to the section specified.</p>
861
Chris Lattner54611b42005-11-06 08:02:57 +0000862<p>An explicit alignment may be specified for a function. If not present, or if
863the alignment is set to zero, the alignment of the function is set by the target
864to whatever it feels convenient. If an explicit alignment is specified, the
865function is forced to have at least that much alignment. All alignments must be
866a power of 2.</p>
867
Devang Patel02256232008-10-07 17:48:33 +0000868 <h5>Syntax:</h5>
869
870<div class="doc_code">
Chris Lattner0ae02092008-10-13 16:55:18 +0000871<tt>
872define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
873 [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
874 &lt;ResultType&gt; @&lt;FunctionName&gt; ([argument list])
875 [<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
876 [<a href="#gc">gc</a>] { ... }
877</tt>
Devang Patel02256232008-10-07 17:48:33 +0000878</div>
879
Chris Lattner6af02f32004-12-09 16:11:40 +0000880</div>
881
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000882
883<!-- ======================================================================= -->
884<div class="doc_subsection">
885 <a name="aliasstructure">Aliases</a>
886</div>
887<div class="doc_text">
888 <p>Aliases act as "second name" for the aliasee value (which can be either
Anton Korobeynikov25b2e822008-03-22 08:36:14 +0000889 function, global variable, another alias or bitcast of global value). Aliases
890 may have an optional <a href="#linkage">linkage type</a>, and an
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000891 optional <a href="#visibility">visibility style</a>.</p>
892
893 <h5>Syntax:</h5>
894
Bill Wendling3716c5d2007-05-29 09:04:49 +0000895<div class="doc_code">
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000896<pre>
Duncan Sands7e99a942008-09-12 20:48:21 +0000897@&lt;Name&gt; = alias [Linkage] [Visibility] &lt;AliaseeTy&gt; @&lt;Aliasee&gt;
Bill Wendling2d8b9a82007-05-29 09:42:13 +0000898</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +0000899</div>
Anton Korobeynikova97b6942007-04-25 14:27:10 +0000900
901</div>
902
903
904
Chris Lattner91c15c42006-01-23 23:23:47 +0000905<!-- ======================================================================= -->
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000906<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
907<div class="doc_text">
908 <p>The return type and each parameter of a function type may have a set of
909 <i>parameter attributes</i> associated with them. Parameter attributes are
910 used to communicate additional information about the result or parameters of
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000911 a function. Parameter attributes are considered to be part of the function,
912 not of the function type, so functions with different parameter attributes
913 can have the same function type.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000914
Reid Spencercf7ebf52007-01-15 18:27:39 +0000915 <p>Parameter attributes are simple keywords that follow the type specified. If
916 multiple parameter attributes are needed, they are space separated. For
Bill Wendling3716c5d2007-05-29 09:04:49 +0000917 example:</p>
918
919<div class="doc_code">
920<pre>
Nick Lewyckydac78d82009-02-15 23:06:14 +0000921declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattnerd2597d72008-10-04 18:33:34 +0000922declare i32 @atoi(i8 zeroext)
923declare signext i8 @returns_signed_char()
Bill Wendling3716c5d2007-05-29 09:04:49 +0000924</pre>
925</div>
926
Duncan Sandsad0ea2d2007-11-27 13:23:08 +0000927 <p>Note that any attributes for the function result (<tt>nounwind</tt>,
928 <tt>readonly</tt>) come immediately after the argument list.</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000929
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000930 <p>Currently, only the following parameter attributes are defined:</p>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000931 <dl>
Reid Spencer314e1cb2007-07-19 23:13:04 +0000932 <dt><tt>zeroext</tt></dt>
Chris Lattnerd2597d72008-10-04 18:33:34 +0000933 <dd>This indicates to the code generator that the parameter or return value
934 should be zero-extended to a 32-bit value by the caller (for a parameter)
935 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000936
Reid Spencer314e1cb2007-07-19 23:13:04 +0000937 <dt><tt>signext</tt></dt>
Chris Lattnerd2597d72008-10-04 18:33:34 +0000938 <dd>This indicates to the code generator that the parameter or return value
939 should be sign-extended to a 32-bit value by the caller (for a parameter)
940 or the callee (for a return value).</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000941
Anton Korobeynikove8166852007-01-28 14:30:45 +0000942 <dt><tt>inreg</tt></dt>
Dale Johannesenc50ada22008-09-25 20:47:45 +0000943 <dd>This indicates that this parameter or return value should be treated
944 in a special target-dependent fashion during while emitting code for a
945 function call or return (usually, by putting it in a register as opposed
Chris Lattnerd2597d72008-10-04 18:33:34 +0000946 to memory, though some targets use it to distinguish between two different
947 kinds of registers). Use of this attribute is target-specific.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000948
Duncan Sands2a1d8ba2008-10-06 08:14:18 +0000949 <dt><tt><a name="byval">byval</a></tt></dt>
Chris Lattner352ab9b2008-01-15 04:34:22 +0000950 <dd>This indicates that the pointer parameter should really be passed by
951 value to the function. The attribute implies that a hidden copy of the
952 pointee is made between the caller and the callee, so the callee is unable
Chris Lattner1ca5c642008-08-05 18:21:08 +0000953 to modify the value in the callee. This attribute is only valid on LLVM
Chris Lattner352ab9b2008-01-15 04:34:22 +0000954 pointer arguments. It is generally used to pass structs and arrays by
Duncan Sands2a1d8ba2008-10-06 08:14:18 +0000955 value, but is also valid on pointers to scalars. The copy is considered to
956 belong to the caller not the callee (for example,
957 <tt><a href="#readonly">readonly</a></tt> functions should not write to
Devang Patel7e9b05e2008-10-06 18:50:38 +0000958 <tt>byval</tt> parameters). This is not a valid attribute for return
Chris Lattner08aa9062009-02-05 05:42:28 +0000959 values. The byval attribute also supports specifying an alignment with the
960 align attribute. This has a target-specific effect on the code generator
961 that usually indicates a desired alignment for the synthesized stack
962 slot.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000963
Anton Korobeynikove8166852007-01-28 14:30:45 +0000964 <dt><tt>sret</tt></dt>
Duncan Sandsfa4b6732008-02-18 04:19:38 +0000965 <dd>This indicates that the pointer parameter specifies the address of a
966 structure that is the return value of the function in the source program.
Chris Lattnerd2597d72008-10-04 18:33:34 +0000967 This pointer must be guaranteed by the caller to be valid: loads and stores
968 to the structure may be assumed by the callee to not to trap. This may only
Devang Patel7e9b05e2008-10-06 18:50:38 +0000969 be applied to the first parameter. This is not a valid attribute for
970 return values. </dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000971
Zhou Sheng2444a9a2007-06-05 05:28:26 +0000972 <dt><tt>noalias</tt></dt>
Nick Lewyckyf5ffcbc2008-11-24 03:41:24 +0000973 <dd>This indicates that the pointer does not alias any global or any other
974 parameter. The caller is responsible for ensuring that this is the
Nick Lewyckyd59572c2008-11-24 05:00:44 +0000975 case. On a function return value, <tt>noalias</tt> additionally indicates
976 that the pointer does not alias any other pointers visible to the
Nick Lewycky2abb1082008-12-19 06:39:12 +0000977 caller. For further details, please see the discussion of the NoAlias
978 response in
979 <a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
980 analysis</a>.</dd>
981
982 <dt><tt>nocapture</tt></dt>
983 <dd>This indicates that the callee does not make any copies of the pointer
984 that outlive the callee itself. This is not a valid attribute for return
985 values.</dd>
Chris Lattner5cee13f2008-01-11 06:20:47 +0000986
Duncan Sands27e91592007-07-27 19:57:41 +0000987 <dt><tt>nest</tt></dt>
Duncan Sands825bde42008-07-08 09:27:25 +0000988 <dd>This indicates that the pointer parameter can be excised using the
Devang Patel7e9b05e2008-10-06 18:50:38 +0000989 <a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
990 attribute for return values.</dd>
Anton Korobeynikova0554d92007-01-12 19:20:47 +0000991 </dl>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000992
Reid Spencerb5ebf3d2006-12-31 07:07:53 +0000993</div>
994
995<!-- ======================================================================= -->
Chris Lattner91c15c42006-01-23 23:23:47 +0000996<div class="doc_subsection">
Gordon Henriksen71183b62007-12-10 03:18:06 +0000997 <a name="gc">Garbage Collector Names</a>
998</div>
999
1000<div class="doc_text">
1001<p>Each function may specify a garbage collector name, which is simply a
1002string.</p>
1003
1004<div class="doc_code"><pre
1005>define void @f() gc "name" { ...</pre></div>
1006
1007<p>The compiler declares the supported values of <i>name</i>. Specifying a
1008collector which will cause the compiler to alter its output in order to support
1009the named garbage collection algorithm.</p>
1010</div>
1011
1012<!-- ======================================================================= -->
1013<div class="doc_subsection">
Devang Patel9eb525d2008-09-26 23:51:19 +00001014 <a name="fnattrs">Function Attributes</a>
Devang Patelcaacdba2008-09-04 23:05:13 +00001015</div>
1016
1017<div class="doc_text">
Devang Patel9eb525d2008-09-26 23:51:19 +00001018
1019<p>Function attributes are set to communicate additional information about
1020 a function. Function attributes are considered to be part of the function,
1021 not of the function type, so functions with different parameter attributes
1022 can have the same function type.</p>
1023
1024 <p>Function attributes are simple keywords that follow the type specified. If
1025 multiple attributes are needed, they are space separated. For
1026 example:</p>
Devang Patelcaacdba2008-09-04 23:05:13 +00001027
1028<div class="doc_code">
Bill Wendlingb175fa42008-09-07 10:26:33 +00001029<pre>
Devang Patel9eb525d2008-09-26 23:51:19 +00001030define void @f() noinline { ... }
1031define void @f() alwaysinline { ... }
1032define void @f() alwaysinline optsize { ... }
1033define void @f() optsize
Bill Wendlingb175fa42008-09-07 10:26:33 +00001034</pre>
Devang Patelcaacdba2008-09-04 23:05:13 +00001035</div>
1036
Bill Wendlingb175fa42008-09-07 10:26:33 +00001037<dl>
Devang Patel9eb525d2008-09-26 23:51:19 +00001038<dt><tt>alwaysinline</tt></dt>
Chris Lattnerfbf60a42008-10-04 18:23:17 +00001039<dd>This attribute indicates that the inliner should attempt to inline this
1040function into callers whenever possible, ignoring any active inlining size
1041threshold for this caller.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +00001042
Devang Patel9eb525d2008-09-26 23:51:19 +00001043<dt><tt>noinline</tt></dt>
Chris Lattnerfbf60a42008-10-04 18:23:17 +00001044<dd>This attribute indicates that the inliner should never inline this function
Chris Lattner0625c282008-10-05 17:14:59 +00001045in any situation. This attribute may not be used together with the
Chris Lattnerfbf60a42008-10-04 18:23:17 +00001046<tt>alwaysinline</tt> attribute.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +00001047
Devang Patel9eb525d2008-09-26 23:51:19 +00001048<dt><tt>optsize</tt></dt>
Devang Patele9743902008-09-29 18:34:44 +00001049<dd>This attribute suggests that optimization passes and code generator passes
Chris Lattnerfbf60a42008-10-04 18:23:17 +00001050make choices that keep the code size of this function low, and otherwise do
1051optimizations specifically to reduce code size.</dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +00001052
Devang Patel9eb525d2008-09-26 23:51:19 +00001053<dt><tt>noreturn</tt></dt>
Chris Lattnerfbf60a42008-10-04 18:23:17 +00001054<dd>This function attribute indicates that the function never returns normally.
1055This produces undefined behavior at runtime if the function ever does
1056dynamically return.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +00001057
1058<dt><tt>nounwind</tt></dt>
Chris Lattnerfbf60a42008-10-04 18:23:17 +00001059<dd>This function attribute indicates that the function never returns with an
1060unwind or exceptional control flow. If the function does unwind, its runtime
1061behavior is undefined.</dd>
1062
1063<dt><tt>readnone</tt></dt>
Duncan Sands2a1d8ba2008-10-06 08:14:18 +00001064<dd>This attribute indicates that the function computes its result (or the
1065exception it throws) based strictly on its arguments, without dereferencing any
1066pointer arguments or otherwise accessing any mutable state (e.g. memory, control
1067registers, etc) visible to caller functions. It does not write through any
1068pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments) and
1069never changes any state visible to callers.</dd>
Devang Patel9eb525d2008-09-26 23:51:19 +00001070
Duncan Sands2a1d8ba2008-10-06 08:14:18 +00001071<dt><tt><a name="readonly">readonly</a></tt></dt>
1072<dd>This attribute indicates that the function does not write through any
1073pointer arguments (including <tt><a href="#byval">byval</a></tt> arguments)
1074or otherwise modify any state (e.g. memory, control registers, etc) visible to
1075caller functions. It may dereference pointer arguments and read state that may
1076be set in the caller. A readonly function always returns the same value (or
1077throws the same exception) when called with the same set of arguments and global
1078state.</dd>
Bill Wendlinga8130172008-11-13 01:02:51 +00001079
1080<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling6e41add2008-11-26 19:19:05 +00001081<dd>This attribute indicates that the function should emit a stack smashing
Bill Wendlinga8130172008-11-13 01:02:51 +00001082protector. It is in the form of a "canary"&mdash;a random value placed on the
1083stack before the local variables that's checked upon return from the function to
1084see if it has been overwritten. A heuristic is used to determine if a function
Bill Wendling6e41add2008-11-26 19:19:05 +00001085needs stack protectors or not.
Bill Wendlinga8130172008-11-13 01:02:51 +00001086
Bill Wendling0f5541e2008-11-26 19:07:40 +00001087<p>If a function that has an <tt>ssp</tt> attribute is inlined into a function
1088that doesn't have an <tt>ssp</tt> attribute, then the resulting function will
1089have an <tt>ssp</tt> attribute.</p></dd>
1090
1091<dt><tt>sspreq</tt></dt>
Bill Wendling6e41add2008-11-26 19:19:05 +00001092<dd>This attribute indicates that the function should <em>always</em> emit a
Bill Wendlinga8130172008-11-13 01:02:51 +00001093stack smashing protector. This overrides the <tt><a href="#ssp">ssp</a></tt>
Bill Wendling6e41add2008-11-26 19:19:05 +00001094function attribute.
Bill Wendling0f5541e2008-11-26 19:07:40 +00001095
1096<p>If a function that has an <tt>sspreq</tt> attribute is inlined into a
1097function that doesn't have an <tt>sspreq</tt> attribute or which has
1098an <tt>ssp</tt> attribute, then the resulting function will have
1099an <tt>sspreq</tt> attribute.</p></dd>
Bill Wendlingb175fa42008-09-07 10:26:33 +00001100</dl>
1101
Devang Patelcaacdba2008-09-04 23:05:13 +00001102</div>
1103
1104<!-- ======================================================================= -->
1105<div class="doc_subsection">
Chris Lattner93564892006-04-08 04:40:53 +00001106 <a name="moduleasm">Module-Level Inline Assembly</a>
Chris Lattner91c15c42006-01-23 23:23:47 +00001107</div>
1108
1109<div class="doc_text">
1110<p>
1111Modules may contain "module-level inline asm" blocks, which corresponds to the
1112GCC "file scope inline asm" blocks. These blocks are internally concatenated by
1113LLVM and treated as a single unit, but may be separated in the .ll file if
1114desired. The syntax is very simple:
1115</p>
1116
Bill Wendling3716c5d2007-05-29 09:04:49 +00001117<div class="doc_code">
1118<pre>
1119module asm "inline asm code goes here"
1120module asm "more can go here"
1121</pre>
1122</div>
Chris Lattner91c15c42006-01-23 23:23:47 +00001123
1124<p>The strings can contain any character by escaping non-printable characters.
1125 The escape sequence used is simply "\xx" where "xx" is the two digit hex code
1126 for the number.
1127</p>
1128
1129<p>
1130 The inline asm code is simply printed to the machine code .s file when
1131 assembly code is generated.
1132</p>
1133</div>
Chris Lattner6af02f32004-12-09 16:11:40 +00001134
Reid Spencer50c723a2007-02-19 23:54:10 +00001135<!-- ======================================================================= -->
1136<div class="doc_subsection">
1137 <a name="datalayout">Data Layout</a>
1138</div>
1139
1140<div class="doc_text">
1141<p>A module may specify a target specific data layout string that specifies how
Reid Spencer7972c472007-04-11 23:49:50 +00001142data is to be laid out in memory. The syntax for the data layout is simply:</p>
1143<pre> target datalayout = "<i>layout specification</i>"</pre>
1144<p>The <i>layout specification</i> consists of a list of specifications
1145separated by the minus sign character ('-'). Each specification starts with a
1146letter and may include other information after the letter to define some
1147aspect of the data layout. The specifications accepted are as follows: </p>
Reid Spencer50c723a2007-02-19 23:54:10 +00001148<dl>
1149 <dt><tt>E</tt></dt>
1150 <dd>Specifies that the target lays out data in big-endian form. That is, the
1151 bits with the most significance have the lowest address location.</dd>
1152 <dt><tt>e</tt></dt>
Chris Lattner67c37d12008-08-05 18:29:16 +00001153 <dd>Specifies that the target lays out data in little-endian form. That is,
Reid Spencer50c723a2007-02-19 23:54:10 +00001154 the bits with the least significance have the lowest address location.</dd>
1155 <dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1156 <dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
1157 <i>preferred</i> alignments. All sizes are in bits. Specifying the <i>pref</i>
1158 alignment is optional. If omitted, the preceding <tt>:</tt> should be omitted
1159 too.</dd>
1160 <dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1161 <dd>This specifies the alignment for an integer type of a given bit
1162 <i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
1163 <dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1164 <dd>This specifies the alignment for a vector type of a given bit
1165 <i>size</i>.</dd>
1166 <dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1167 <dd>This specifies the alignment for a floating point type of a given bit
1168 <i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
1169 (double).</dd>
1170 <dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
1171 <dd>This specifies the alignment for an aggregate type of a given bit
1172 <i>size</i>.</dd>
1173</dl>
1174<p>When constructing the data layout for a given target, LLVM starts with a
1175default set of specifications which are then (possibly) overriden by the
1176specifications in the <tt>datalayout</tt> keyword. The default specifications
1177are given in this list:</p>
1178<ul>
1179 <li><tt>E</tt> - big endian</li>
1180 <li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
1181 <li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
1182 <li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
1183 <li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
1184 <li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner67c37d12008-08-05 18:29:16 +00001185 <li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Reid Spencer50c723a2007-02-19 23:54:10 +00001186 alignment of 64-bits</li>
1187 <li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
1188 <li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
1189 <li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
1190 <li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
1191 <li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
1192</ul>
Chris Lattner1ca5c642008-08-05 18:21:08 +00001193<p>When LLVM is determining the alignment for a given type, it uses the
Dan Gohmanef9462f2008-10-14 16:51:45 +00001194following rules:</p>
Reid Spencer50c723a2007-02-19 23:54:10 +00001195<ol>
1196 <li>If the type sought is an exact match for one of the specifications, that
1197 specification is used.</li>
1198 <li>If no match is found, and the type sought is an integer type, then the
1199 smallest integer type that is larger than the bitwidth of the sought type is
1200 used. If none of the specifications are larger than the bitwidth then the the
1201 largest integer type is used. For example, given the default specifications
1202 above, the i7 type will use the alignment of i8 (next largest) while both
1203 i65 and i256 will use the alignment of i64 (largest specified).</li>
1204 <li>If no match is found, and the type sought is a vector type, then the
1205 largest vector type that is smaller than the sought vector type will be used
Dan Gohmanef9462f2008-10-14 16:51:45 +00001206 as a fall back. This happens because &lt;128 x double&gt; can be implemented
1207 in terms of 64 &lt;2 x double&gt;, for example.</li>
Reid Spencer50c723a2007-02-19 23:54:10 +00001208</ol>
1209</div>
Chris Lattner6af02f32004-12-09 16:11:40 +00001210
Chris Lattner2f7c9632001-06-06 20:29:01 +00001211<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +00001212<div class="doc_section"> <a name="typesystem">Type System</a> </div>
1213<!-- *********************************************************************** -->
Chris Lattner6af02f32004-12-09 16:11:40 +00001214
Misha Brukman76307852003-11-08 01:05:38 +00001215<div class="doc_text">
Chris Lattner6af02f32004-12-09 16:11:40 +00001216
Misha Brukman76307852003-11-08 01:05:38 +00001217<p>The LLVM type system is one of the most important features of the
Chris Lattner48b383b02003-11-25 01:02:51 +00001218intermediate representation. Being typed enables a number of
Chris Lattner67c37d12008-08-05 18:29:16 +00001219optimizations to be performed on the intermediate representation directly,
1220without having to do
Chris Lattner48b383b02003-11-25 01:02:51 +00001221extra analyses on the side before the transformation. A strong type
1222system makes it easier to read the generated code and enables novel
1223analyses and transformations that are not feasible to perform on normal
1224three address code representations.</p>
Chris Lattner6af02f32004-12-09 16:11:40 +00001225
1226</div>
1227
Chris Lattner2f7c9632001-06-06 20:29:01 +00001228<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +00001229<div class="doc_subsection"> <a name="t_classifications">Type
Chris Lattner48b383b02003-11-25 01:02:51 +00001230Classifications</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00001231<div class="doc_text">
Chris Lattner7824d182008-01-04 04:32:38 +00001232<p>The types fall into a few useful
Chris Lattner48b383b02003-11-25 01:02:51 +00001233classifications:</p>
Misha Brukmanc501f552004-03-01 17:47:27 +00001234
1235<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +00001236 <tbody>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001237 <tr><th>Classification</th><th>Types</th></tr>
Chris Lattner48b383b02003-11-25 01:02:51 +00001238 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +00001239 <td><a href="#t_integer">integer</a></td>
Reid Spencer138249b2007-05-16 18:44:01 +00001240 <td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +00001241 </tr>
1242 <tr>
Chris Lattner7824d182008-01-04 04:32:38 +00001243 <td><a href="#t_floating">floating point</a></td>
1244 <td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Chris Lattner48b383b02003-11-25 01:02:51 +00001245 </tr>
1246 <tr>
1247 <td><a name="t_firstclass">first class</a></td>
Chris Lattner7824d182008-01-04 04:32:38 +00001248 <td><a href="#t_integer">integer</a>,
1249 <a href="#t_floating">floating point</a>,
1250 <a href="#t_pointer">pointer</a>,
Dan Gohman08783a882008-06-18 18:42:13 +00001251 <a href="#t_vector">vector</a>,
Dan Gohmanb9d66602008-05-12 23:51:09 +00001252 <a href="#t_struct">structure</a>,
1253 <a href="#t_array">array</a>,
Dan Gohmanda52d212008-05-23 22:50:26 +00001254 <a href="#t_label">label</a>.
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00001255 </td>
Chris Lattner48b383b02003-11-25 01:02:51 +00001256 </tr>
Chris Lattner7824d182008-01-04 04:32:38 +00001257 <tr>
1258 <td><a href="#t_primitive">primitive</a></td>
1259 <td><a href="#t_label">label</a>,
1260 <a href="#t_void">void</a>,
Chris Lattner7824d182008-01-04 04:32:38 +00001261 <a href="#t_floating">floating point</a>.</td>
1262 </tr>
1263 <tr>
1264 <td><a href="#t_derived">derived</a></td>
1265 <td><a href="#t_integer">integer</a>,
1266 <a href="#t_array">array</a>,
1267 <a href="#t_function">function</a>,
1268 <a href="#t_pointer">pointer</a>,
1269 <a href="#t_struct">structure</a>,
1270 <a href="#t_pstruct">packed structure</a>,
1271 <a href="#t_vector">vector</a>,
1272 <a href="#t_opaque">opaque</a>.
Dan Gohman93bf60d2008-10-14 16:32:04 +00001273 </td>
Chris Lattner7824d182008-01-04 04:32:38 +00001274 </tr>
Chris Lattner48b383b02003-11-25 01:02:51 +00001275 </tbody>
Misha Brukman76307852003-11-08 01:05:38 +00001276</table>
Misha Brukmanc501f552004-03-01 17:47:27 +00001277
Chris Lattner48b383b02003-11-25 01:02:51 +00001278<p>The <a href="#t_firstclass">first class</a> types are perhaps the
1279most important. Values of these types are the only ones which can be
1280produced by instructions, passed as arguments, or used as operands to
Dan Gohman34d1c0d2008-05-23 21:53:15 +00001281instructions.</p>
Misha Brukman76307852003-11-08 01:05:38 +00001282</div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001283
Chris Lattner2f7c9632001-06-06 20:29:01 +00001284<!-- ======================================================================= -->
Chris Lattner7824d182008-01-04 04:32:38 +00001285<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner43542b32008-01-04 04:34:14 +00001286
Chris Lattner7824d182008-01-04 04:32:38 +00001287<div class="doc_text">
1288<p>The primitive types are the fundamental building blocks of the LLVM
1289system.</p>
1290
Chris Lattner43542b32008-01-04 04:34:14 +00001291</div>
1292
Chris Lattner7824d182008-01-04 04:32:38 +00001293<!-- _______________________________________________________________________ -->
1294<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
1295
1296<div class="doc_text">
1297 <table>
1298 <tbody>
1299 <tr><th>Type</th><th>Description</th></tr>
1300 <tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
1301 <tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
1302 <tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
1303 <tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
1304 <tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
1305 </tbody>
1306 </table>
1307</div>
1308
1309<!-- _______________________________________________________________________ -->
1310<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
1311
1312<div class="doc_text">
1313<h5>Overview:</h5>
1314<p>The void type does not represent any value and has no size.</p>
1315
1316<h5>Syntax:</h5>
1317
1318<pre>
1319 void
1320</pre>
1321</div>
1322
1323<!-- _______________________________________________________________________ -->
1324<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
1325
1326<div class="doc_text">
1327<h5>Overview:</h5>
1328<p>The label type represents code labels.</p>
1329
1330<h5>Syntax:</h5>
1331
1332<pre>
1333 label
1334</pre>
1335</div>
1336
1337
1338<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +00001339<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001340
Misha Brukman76307852003-11-08 01:05:38 +00001341<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +00001342
Chris Lattner48b383b02003-11-25 01:02:51 +00001343<p>The real power in LLVM comes from the derived types in the system.
1344This is what allows a programmer to represent arrays, functions,
1345pointers, and other useful types. Note that these derived types may be
1346recursive: For example, it is possible to have a two dimensional array.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001347
Misha Brukman76307852003-11-08 01:05:38 +00001348</div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001349
Chris Lattner2f7c9632001-06-06 20:29:01 +00001350<!-- _______________________________________________________________________ -->
Reid Spencer138249b2007-05-16 18:44:01 +00001351<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
1352
1353<div class="doc_text">
1354
1355<h5>Overview:</h5>
1356<p>The integer type is a very simple derived type that simply specifies an
1357arbitrary bit width for the integer type desired. Any bit width from 1 bit to
13582^23-1 (about 8 million) can be specified.</p>
1359
1360<h5>Syntax:</h5>
1361
1362<pre>
1363 iN
1364</pre>
1365
1366<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
1367value.</p>
1368
1369<h5>Examples:</h5>
1370<table class="layout">
Chris Lattner9a2e3cb2007-12-18 06:18:21 +00001371 <tbody>
1372 <tr>
1373 <td><tt>i1</tt></td>
1374 <td>a single-bit integer.</td>
1375 </tr><tr>
1376 <td><tt>i32</tt></td>
1377 <td>a 32-bit integer.</td>
1378 </tr><tr>
1379 <td><tt>i1942652</tt></td>
1380 <td>a really big integer of over 1 million bits.</td>
Reid Spencer138249b2007-05-16 18:44:01 +00001381 </tr>
Chris Lattner9a2e3cb2007-12-18 06:18:21 +00001382 </tbody>
Reid Spencer138249b2007-05-16 18:44:01 +00001383</table>
Dan Gohman142ccc02009-01-24 15:58:40 +00001384
1385<p>Note that the code generator does not yet support large integer types
1386to be used as function return types. The specific limit on how large a
1387return type the code generator can currently handle is target-dependent;
1388currently it's often 64 bits for 32-bit targets and 128 bits for 64-bit
1389targets.</p>
1390
Bill Wendling3716c5d2007-05-29 09:04:49 +00001391</div>
Reid Spencer138249b2007-05-16 18:44:01 +00001392
1393<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00001394<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001395
Misha Brukman76307852003-11-08 01:05:38 +00001396<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +00001397
Chris Lattner2f7c9632001-06-06 20:29:01 +00001398<h5>Overview:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +00001399
Misha Brukman76307852003-11-08 01:05:38 +00001400<p>The array type is a very simple derived type that arranges elements
Chris Lattner48b383b02003-11-25 01:02:51 +00001401sequentially in memory. The array type requires a size (number of
1402elements) and an underlying data type.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001403
Chris Lattner590645f2002-04-14 06:13:44 +00001404<h5>Syntax:</h5>
Chris Lattner74d3f822004-12-09 17:30:23 +00001405
1406<pre>
1407 [&lt;# elements&gt; x &lt;elementtype&gt;]
1408</pre>
1409
John Criswell02fdc6f2005-05-12 16:52:32 +00001410<p>The number of elements is a constant integer value; elementtype may
Chris Lattner48b383b02003-11-25 01:02:51 +00001411be any type with a size.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001412
Chris Lattner590645f2002-04-14 06:13:44 +00001413<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001414<table class="layout">
1415 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +00001416 <td class="left"><tt>[40 x i32]</tt></td>
1417 <td class="left">Array of 40 32-bit integer values.</td>
1418 </tr>
1419 <tr class="layout">
1420 <td class="left"><tt>[41 x i32]</tt></td>
1421 <td class="left">Array of 41 32-bit integer values.</td>
1422 </tr>
1423 <tr class="layout">
1424 <td class="left"><tt>[4 x i8]</tt></td>
1425 <td class="left">Array of 4 8-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001426 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +00001427</table>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001428<p>Here are some examples of multidimensional arrays:</p>
1429<table class="layout">
1430 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +00001431 <td class="left"><tt>[3 x [4 x i32]]</tt></td>
1432 <td class="left">3x4 array of 32-bit integer values.</td>
1433 </tr>
1434 <tr class="layout">
1435 <td class="left"><tt>[12 x [10 x float]]</tt></td>
1436 <td class="left">12x10 array of single precision floating point values.</td>
1437 </tr>
1438 <tr class="layout">
1439 <td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
1440 <td class="left">2x3x4 array of 16-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001441 </tr>
1442</table>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +00001443
John Criswell4c0cf7f2005-10-24 16:17:18 +00001444<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
1445length array. Normally, accesses past the end of an array are undefined in
Chris Lattnerc0ad71e2005-06-24 17:22:57 +00001446LLVM (e.g. it is illegal to access the 5th element of a 3 element array).
1447As a special case, however, zero length arrays are recognized to be variable
1448length. This allows implementation of 'pascal style arrays' with the LLVM
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00001449type "{ i32, [0 x float]}", for example.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +00001450
Dan Gohman142ccc02009-01-24 15:58:40 +00001451<p>Note that the code generator does not yet support large aggregate types
1452to be used as function return types. The specific limit on how large an
1453aggregate return type the code generator can currently handle is
1454target-dependent, and also dependent on the aggregate element types.</p>
1455
Misha Brukman76307852003-11-08 01:05:38 +00001456</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001457
Chris Lattner2f7c9632001-06-06 20:29:01 +00001458<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00001459<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00001460<div class="doc_text">
Chris Lattnerda508ac2008-04-23 04:59:35 +00001461
Chris Lattner2f7c9632001-06-06 20:29:01 +00001462<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +00001463
Chris Lattner48b383b02003-11-25 01:02:51 +00001464<p>The function type can be thought of as a function signature. It
Devang Patele3dfc1c2008-03-24 05:35:41 +00001465consists of a return type and a list of formal parameter types. The
Chris Lattnerda508ac2008-04-23 04:59:35 +00001466return type of a function type is a scalar type, a void type, or a struct type.
Devang Patel9c1f8b12008-03-24 20:52:42 +00001467If the return type is a struct type then all struct elements must be of first
Chris Lattnerda508ac2008-04-23 04:59:35 +00001468class types, and the struct must have at least one element.</p>
Devang Pateld6cff512008-03-10 20:49:15 +00001469
Chris Lattner2f7c9632001-06-06 20:29:01 +00001470<h5>Syntax:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +00001471
1472<pre>
1473 &lt;returntype list&gt; (&lt;parameter list&gt;)
1474</pre>
1475
John Criswell4c0cf7f2005-10-24 16:17:18 +00001476<p>...where '<tt>&lt;parameter list&gt;</tt>' is a comma-separated list of type
Misha Brukman20f9a622004-08-12 20:16:08 +00001477specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
Chris Lattner5ed60612003-09-03 00:41:47 +00001478which indicates that the function takes a variable number of arguments.
1479Variable argument functions can access their arguments with the <a
Devang Pateld6cff512008-03-10 20:49:15 +00001480 href="#int_varargs">variable argument handling intrinsic</a> functions.
1481'<tt>&lt;returntype list&gt;</tt>' is a comma-separated list of
1482<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +00001483
Chris Lattner2f7c9632001-06-06 20:29:01 +00001484<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001485<table class="layout">
1486 <tr class="layout">
Reid Spencer58c08712006-12-31 07:18:34 +00001487 <td class="left"><tt>i32 (i32)</tt></td>
1488 <td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001489 </td>
Reid Spencer58c08712006-12-31 07:18:34 +00001490 </tr><tr class="layout">
Reid Spencer314e1cb2007-07-19 23:13:04 +00001491 <td class="left"><tt>float&nbsp;(i16&nbsp;signext,&nbsp;i32&nbsp;*)&nbsp;*
Reid Spencer655dcc62006-12-31 07:20:23 +00001492 </tt></td>
Reid Spencer58c08712006-12-31 07:18:34 +00001493 <td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
1494 an <tt>i16</tt> that should be sign extended and a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00001495 <a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
Reid Spencer58c08712006-12-31 07:18:34 +00001496 <tt>float</tt>.
1497 </td>
1498 </tr><tr class="layout">
1499 <td class="left"><tt>i32 (i8*, ...)</tt></td>
1500 <td class="left">A vararg function that takes at least one
Reid Spencer3e628eb92007-01-04 16:43:23 +00001501 <a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
Reid Spencer58c08712006-12-31 07:18:34 +00001502 which returns an integer. This is the signature for <tt>printf</tt> in
1503 LLVM.
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001504 </td>
Devang Patele3dfc1c2008-03-24 05:35:41 +00001505 </tr><tr class="layout">
1506 <td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukmanc9813bd2008-11-27 06:41:20 +00001507 <td class="left">A function taking an <tt>i32</tt>, returning two
1508 <tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patele3dfc1c2008-03-24 05:35:41 +00001509 </td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001510 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +00001511</table>
Misha Brukmanc501f552004-03-01 17:47:27 +00001512
Misha Brukman76307852003-11-08 01:05:38 +00001513</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00001514<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00001515<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00001516<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00001517<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00001518<p>The structure type is used to represent a collection of data members
1519together in memory. The packing of the field types is defined to match
1520the ABI of the underlying processor. The elements of a structure may
1521be any type that has a size.</p>
1522<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1523and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1524field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1525instruction.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00001526<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00001527<pre> { &lt;type list&gt; }<br></pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +00001528<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001529<table class="layout">
1530 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +00001531 <td class="left"><tt>{ i32, i32, i32 }</tt></td>
1532 <td class="left">A triple of three <tt>i32</tt> values</td>
1533 </tr><tr class="layout">
1534 <td class="left"><tt>{&nbsp;float,&nbsp;i32&nbsp;(i32)&nbsp;*&nbsp;}</tt></td>
1535 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1536 second element is a <a href="#t_pointer">pointer</a> to a
1537 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1538 an <tt>i32</tt>.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001539 </tr>
Chris Lattner2f7c9632001-06-06 20:29:01 +00001540</table>
Dan Gohman142ccc02009-01-24 15:58:40 +00001541
1542<p>Note that the code generator does not yet support large aggregate types
1543to be used as function return types. The specific limit on how large an
1544aggregate return type the code generator can currently handle is
1545target-dependent, and also dependent on the aggregate element types.</p>
1546
Misha Brukman76307852003-11-08 01:05:38 +00001547</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001548
Chris Lattner2f7c9632001-06-06 20:29:01 +00001549<!-- _______________________________________________________________________ -->
Andrew Lenharth8df88e22006-12-08 17:13:00 +00001550<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
1551</div>
1552<div class="doc_text">
1553<h5>Overview:</h5>
1554<p>The packed structure type is used to represent a collection of data members
1555together in memory. There is no padding between fields. Further, the alignment
1556of a packed structure is 1 byte. The elements of a packed structure may
1557be any type that has a size.</p>
1558<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt>
1559and '<tt><a href="#i_store">store</a></tt>' by getting a pointer to a
1560field with the '<tt><a href="#i_getelementptr">getelementptr</a></tt>'
1561instruction.</p>
1562<h5>Syntax:</h5>
1563<pre> &lt; { &lt;type list&gt; } &gt; <br></pre>
1564<h5>Examples:</h5>
1565<table class="layout">
1566 <tr class="layout">
Jeff Cohen5819f182007-04-22 01:17:39 +00001567 <td class="left"><tt>&lt; { i32, i32, i32 } &gt;</tt></td>
1568 <td class="left">A triple of three <tt>i32</tt> values</td>
1569 </tr><tr class="layout">
Bill Wendlingb175fa42008-09-07 10:26:33 +00001570 <td class="left">
1571<tt>&lt;&nbsp;{&nbsp;float,&nbsp;i32&nbsp;(i32)*&nbsp;}&nbsp;&gt;</tt></td>
Jeff Cohen5819f182007-04-22 01:17:39 +00001572 <td class="left">A pair, where the first element is a <tt>float</tt> and the
1573 second element is a <a href="#t_pointer">pointer</a> to a
1574 <a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
1575 an <tt>i32</tt>.</td>
Andrew Lenharth8df88e22006-12-08 17:13:00 +00001576 </tr>
1577</table>
1578</div>
1579
1580<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00001581<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00001582<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +00001583<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00001584<p>As in many languages, the pointer type represents a pointer or
Christopher Lamb308121c2007-12-11 09:31:00 +00001585reference to another object, which must live in memory. Pointer types may have
1586an optional address space attribute defining the target-specific numbered
1587address space where the pointed-to object resides. The default address space is
1588zero.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +00001589
1590<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does
Chris Lattnerd1d4cff2009-02-08 22:21:28 +00001591it permit pointers to labels (<tt>label*</tt>). Use <tt>i8*</tt> instead.</p>
Chris Lattner4a67c912009-02-08 19:53:29 +00001592
Chris Lattner590645f2002-04-14 06:13:44 +00001593<h5>Syntax:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00001594<pre> &lt;type&gt; *<br></pre>
Chris Lattner590645f2002-04-14 06:13:44 +00001595<h5>Examples:</h5>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001596<table class="layout">
1597 <tr class="layout">
Dan Gohman623806e2009-01-04 23:44:43 +00001598 <td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner747359f2007-12-19 05:04:11 +00001599 <td class="left">A <a href="#t_pointer">pointer</a> to <a
1600 href="#t_array">array</a> of four <tt>i32</tt> values.</td>
1601 </tr>
1602 <tr class="layout">
1603 <td class="left"><tt>i32 (i32 *) *</tt></td>
1604 <td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00001605 href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner747359f2007-12-19 05:04:11 +00001606 <tt>i32</tt>.</td>
1607 </tr>
1608 <tr class="layout">
1609 <td class="left"><tt>i32 addrspace(5)*</tt></td>
1610 <td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
1611 that resides in address space #5.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001612 </tr>
Misha Brukman76307852003-11-08 01:05:38 +00001613</table>
Misha Brukman76307852003-11-08 01:05:38 +00001614</div>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001615
Chris Lattnerc8cb6952004-08-12 19:12:28 +00001616<!-- _______________________________________________________________________ -->
Reid Spencer404a3252007-02-15 03:07:05 +00001617<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00001618<div class="doc_text">
Chris Lattner37b6b092005-04-25 17:34:15 +00001619
Chris Lattnerc8cb6952004-08-12 19:12:28 +00001620<h5>Overview:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +00001621
Reid Spencer404a3252007-02-15 03:07:05 +00001622<p>A vector type is a simple derived type that represents a vector
1623of elements. Vector types are used when multiple primitive data
Chris Lattnerc8cb6952004-08-12 19:12:28 +00001624are operated in parallel using a single instruction (SIMD).
Reid Spencer404a3252007-02-15 03:07:05 +00001625A vector type requires a size (number of
Chris Lattner330ce692005-11-10 01:44:22 +00001626elements) and an underlying primitive data type. Vectors must have a power
Reid Spencer404a3252007-02-15 03:07:05 +00001627of two length (1, 2, 4, 8, 16 ...). Vector types are
Chris Lattnerc8cb6952004-08-12 19:12:28 +00001628considered <a href="#t_firstclass">first class</a>.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +00001629
Chris Lattnerc8cb6952004-08-12 19:12:28 +00001630<h5>Syntax:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +00001631
1632<pre>
1633 &lt; &lt;# elements&gt; x &lt;elementtype&gt; &gt;
1634</pre>
1635
John Criswell4a3327e2005-05-13 22:25:59 +00001636<p>The number of elements is a constant integer value; elementtype may
Chris Lattnerc0f423a2007-01-15 01:54:13 +00001637be any integer or floating point type.</p>
Chris Lattner37b6b092005-04-25 17:34:15 +00001638
Chris Lattnerc8cb6952004-08-12 19:12:28 +00001639<h5>Examples:</h5>
Chris Lattner37b6b092005-04-25 17:34:15 +00001640
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001641<table class="layout">
1642 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +00001643 <td class="left"><tt>&lt;4 x i32&gt;</tt></td>
1644 <td class="left">Vector of 4 32-bit integer values.</td>
1645 </tr>
1646 <tr class="layout">
1647 <td class="left"><tt>&lt;8 x float&gt;</tt></td>
1648 <td class="left">Vector of 8 32-bit floating-point values.</td>
1649 </tr>
1650 <tr class="layout">
1651 <td class="left"><tt>&lt;2 x i64&gt;</tt></td>
1652 <td class="left">Vector of 2 64-bit integer values.</td>
Reid Spencerc3c4c4f2004-11-01 08:19:36 +00001653 </tr>
1654</table>
Dan Gohman142ccc02009-01-24 15:58:40 +00001655
1656<p>Note that the code generator does not yet support large vector types
1657to be used as function return types. The specific limit on how large a
1658vector return type codegen can currently handle is target-dependent;
1659currently it's often a few times longer than a hardware vector register.</p>
1660
Misha Brukman76307852003-11-08 01:05:38 +00001661</div>
1662
Chris Lattner37b6b092005-04-25 17:34:15 +00001663<!-- _______________________________________________________________________ -->
1664<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
1665<div class="doc_text">
1666
1667<h5>Overview:</h5>
1668
1669<p>Opaque types are used to represent unknown types in the system. This
Gordon Henriksena699c4d2007-10-14 00:34:53 +00001670corresponds (for example) to the C notion of a forward declared structure type.
Chris Lattner37b6b092005-04-25 17:34:15 +00001671In LLVM, opaque types can eventually be resolved to any type (not just a
1672structure type).</p>
1673
1674<h5>Syntax:</h5>
1675
1676<pre>
1677 opaque
1678</pre>
1679
1680<h5>Examples:</h5>
1681
1682<table class="layout">
1683 <tr class="layout">
Chris Lattner747359f2007-12-19 05:04:11 +00001684 <td class="left"><tt>opaque</tt></td>
1685 <td class="left">An opaque type.</td>
Chris Lattner37b6b092005-04-25 17:34:15 +00001686 </tr>
1687</table>
1688</div>
1689
Chris Lattnercf7a5842009-02-02 07:32:36 +00001690<!-- ======================================================================= -->
1691<div class="doc_subsection">
1692 <a name="t_uprefs">Type Up-references</a>
1693</div>
1694
1695<div class="doc_text">
1696<h5>Overview:</h5>
1697<p>
1698An "up reference" allows you to refer to a lexically enclosing type without
1699requiring it to have a name. For instance, a structure declaration may contain a
1700pointer to any of the types it is lexically a member of. Example of up
1701references (with their equivalent as named type declarations) include:</p>
1702
1703<pre>
Chris Lattnerbf1d5452009-02-09 10:00:56 +00001704 { \2 * } %x = type { %x* }
Chris Lattnercf7a5842009-02-02 07:32:36 +00001705 { \2 }* %y = type { %y }*
1706 \1* %z = type %z*
1707</pre>
1708
1709<p>
1710An up reference is needed by the asmprinter for printing out cyclic types when
1711there is no declared name for a type in the cycle. Because the asmprinter does
1712not want to print out an infinite type string, it needs a syntax to handle
1713recursive types that have no names (all names are optional in llvm IR).
1714</p>
1715
1716<h5>Syntax:</h5>
1717<pre>
1718 \&lt;level&gt;
1719</pre>
1720
1721<p>
1722The level is the count of the lexical type that is being referred to.
1723</p>
1724
1725<h5>Examples:</h5>
1726
1727<table class="layout">
1728 <tr class="layout">
1729 <td class="left"><tt>\1*</tt></td>
1730 <td class="left">Self-referential pointer.</td>
1731 </tr>
1732 <tr class="layout">
1733 <td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
1734 <td class="left">Recursive structure where the upref refers to the out-most
1735 structure.</td>
1736 </tr>
1737</table>
1738</div>
1739
Chris Lattner37b6b092005-04-25 17:34:15 +00001740
Chris Lattner74d3f822004-12-09 17:30:23 +00001741<!-- *********************************************************************** -->
1742<div class="doc_section"> <a name="constants">Constants</a> </div>
1743<!-- *********************************************************************** -->
1744
1745<div class="doc_text">
1746
1747<p>LLVM has several different basic types of constants. This section describes
1748them all and their syntax.</p>
1749
1750</div>
1751
1752<!-- ======================================================================= -->
Reid Spencer8f08d802004-12-09 18:02:53 +00001753<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001754
1755<div class="doc_text">
1756
1757<dl>
1758 <dt><b>Boolean constants</b></dt>
1759
1760 <dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Reid Spencer36a15422007-01-12 03:35:51 +00001761 constants of the <tt><a href="#t_primitive">i1</a></tt> type.
Chris Lattner74d3f822004-12-09 17:30:23 +00001762 </dd>
1763
1764 <dt><b>Integer constants</b></dt>
1765
Reid Spencer8f08d802004-12-09 18:02:53 +00001766 <dd>Standard integers (such as '4') are constants of the <a
Reid Spencer3e628eb92007-01-04 16:43:23 +00001767 href="#t_integer">integer</a> type. Negative numbers may be used with
Chris Lattner74d3f822004-12-09 17:30:23 +00001768 integer types.
1769 </dd>
1770
1771 <dt><b>Floating point constants</b></dt>
1772
1773 <dd>Floating point constants use standard decimal notation (e.g. 123.421),
1774 exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
Chris Lattner1429e6f2008-04-01 18:45:27 +00001775 notation (see below). The assembler requires the exact decimal value of
1776 a floating-point constant. For example, the assembler accepts 1.25 but
1777 rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
1778 constants must have a <a href="#t_floating">floating point</a> type. </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +00001779
1780 <dt><b>Null pointer constants</b></dt>
1781
John Criswelldfe6a862004-12-10 15:51:16 +00001782 <dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Chris Lattner74d3f822004-12-09 17:30:23 +00001783 and must be of <a href="#t_pointer">pointer type</a>.</dd>
1784
1785</dl>
1786
Dale Johannesencd4a3012009-02-11 22:14:51 +00001787<p>The one non-intuitive notation for constants is the hexadecimal form
Chris Lattner74d3f822004-12-09 17:30:23 +00001788of floating point constants. For example, the form '<tt>double
17890x432ff973cafa8000</tt>' is equivalent to (but harder to read than) '<tt>double
17904.5e+15</tt>'. The only time hexadecimal floating point constants are required
Reid Spencer8f08d802004-12-09 18:02:53 +00001791(and the only time that they are generated by the disassembler) is when a
1792floating point constant must be emitted but it cannot be represented as a
Dale Johannesencd4a3012009-02-11 22:14:51 +00001793decimal floating point number in a reasonable number of digits. For example,
1794NaN's, infinities, and other
Reid Spencer8f08d802004-12-09 18:02:53 +00001795special values are represented in their IEEE hexadecimal format so that
1796assembly and disassembly do not cause any bits to change in the constants.</p>
Dale Johannesencd4a3012009-02-11 22:14:51 +00001797<p>When using the hexadecimal form, constants of types float and double are
1798represented using the 16-digit form shown above (which matches the IEEE754
1799representation for double); float values must, however, be exactly representable
1800as IEE754 single precision.
1801Hexadecimal format is always used for long
1802double, and there are three forms of long double. The 80-bit
1803format used by x86 is represented as <tt>0xK</tt>
1804followed by 20 hexadecimal digits.
1805The 128-bit format used by PowerPC (two adjacent doubles) is represented
1806by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit
1807format is represented
1808by <tt>0xL</tt> followed by 32 hexadecimal digits; no currently supported
1809target uses this format. Long doubles will only work if they match
1810the long double format on your target. All hexadecimal formats are big-endian
1811(sign bit at the left).</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001812</div>
1813
1814<!-- ======================================================================= -->
Chris Lattner361bfcd2009-02-28 18:32:25 +00001815<div class="doc_subsection">
1816<a name="aggregateconstants"> <!-- old anchor -->
1817<a name="complexconstants">Complex Constants</a></a>
Chris Lattner74d3f822004-12-09 17:30:23 +00001818</div>
1819
1820<div class="doc_text">
Chris Lattner361bfcd2009-02-28 18:32:25 +00001821<p>Complex constants are a (potentially recursive) combination of simple
1822constants and smaller complex constants.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001823
1824<dl>
1825 <dt><b>Structure constants</b></dt>
1826
1827 <dd>Structure constants are represented with notation similar to structure
1828 type definitions (a comma separated list of elements, surrounded by braces
Chris Lattnerbea11172007-12-25 20:34:52 +00001829 (<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
1830 where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>". Structure constants
Chris Lattner455fc8c2005-03-07 22:13:59 +00001831 must have <a href="#t_struct">structure type</a>, and the number and
Chris Lattner74d3f822004-12-09 17:30:23 +00001832 types of elements must match those specified by the type.
1833 </dd>
1834
1835 <dt><b>Array constants</b></dt>
1836
1837 <dd>Array constants are represented with notation similar to array type
1838 definitions (a comma separated list of elements, surrounded by square brackets
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00001839 (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74 ]</tt>". Array
Chris Lattner74d3f822004-12-09 17:30:23 +00001840 constants must have <a href="#t_array">array type</a>, and the number and
1841 types of elements must match those specified by the type.
1842 </dd>
1843
Reid Spencer404a3252007-02-15 03:07:05 +00001844 <dt><b>Vector constants</b></dt>
Chris Lattner74d3f822004-12-09 17:30:23 +00001845
Reid Spencer404a3252007-02-15 03:07:05 +00001846 <dd>Vector constants are represented with notation similar to vector type
Chris Lattner74d3f822004-12-09 17:30:23 +00001847 definitions (a comma separated list of elements, surrounded by
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00001848 less-than/greater-than's (<tt>&lt;&gt;</tt>)). For example: "<tt>&lt; i32 42,
Jeff Cohen5819f182007-04-22 01:17:39 +00001849 i32 11, i32 74, i32 100 &gt;</tt>". Vector constants must have <a
Reid Spencer404a3252007-02-15 03:07:05 +00001850 href="#t_vector">vector type</a>, and the number and types of elements must
Chris Lattner74d3f822004-12-09 17:30:23 +00001851 match those specified by the type.
1852 </dd>
1853
1854 <dt><b>Zero initialization</b></dt>
1855
1856 <dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
1857 value to zero of <em>any</em> type, including scalar and aggregate types.
1858 This is often used to avoid having to print large zero initializers (e.g. for
John Criswell4c0cf7f2005-10-24 16:17:18 +00001859 large arrays) and is always exactly equivalent to using explicit zero
Chris Lattner74d3f822004-12-09 17:30:23 +00001860 initializers.
1861 </dd>
Nick Lewycky49f89192009-04-04 07:22:01 +00001862
1863 <dt><b>Metadata node</b></dt>
1864
1865 <dd>A metadata node is a structure-like constant with the type of an empty
1866 struct. For example: "<tt>{ } !{ i32 0, { } !"test" }</tt>". Unlike other
1867 constants that are meant to be interpreted as part of the instruction stream,
1868 metadata is a place to attach additional information such as debug info.
1869 </dd>
Chris Lattner74d3f822004-12-09 17:30:23 +00001870</dl>
1871
1872</div>
1873
1874<!-- ======================================================================= -->
1875<div class="doc_subsection">
1876 <a name="globalconstants">Global Variable and Function Addresses</a>
1877</div>
1878
1879<div class="doc_text">
1880
1881<p>The addresses of <a href="#globalvars">global variables</a> and <a
1882href="#functionstructure">functions</a> are always implicitly valid (link-time)
John Criswelldfe6a862004-12-10 15:51:16 +00001883constants. These constants are explicitly referenced when the <a
1884href="#identifiers">identifier for the global</a> is used and always have <a
Chris Lattner74d3f822004-12-09 17:30:23 +00001885href="#t_pointer">pointer</a> type. For example, the following is a legal LLVM
1886file:</p>
1887
Bill Wendling3716c5d2007-05-29 09:04:49 +00001888<div class="doc_code">
Chris Lattner74d3f822004-12-09 17:30:23 +00001889<pre>
Chris Lattner00538a12007-06-06 18:28:13 +00001890@X = global i32 17
1891@Y = global i32 42
1892@Z = global [2 x i32*] [ i32* @X, i32* @Y ]
Chris Lattner74d3f822004-12-09 17:30:23 +00001893</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00001894</div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001895
1896</div>
1897
1898<!-- ======================================================================= -->
Reid Spencer641f5c92004-12-09 18:13:12 +00001899<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
Chris Lattner74d3f822004-12-09 17:30:23 +00001900<div class="doc_text">
Reid Spencer641f5c92004-12-09 18:13:12 +00001901 <p>The string '<tt>undef</tt>' is recognized as a type-less constant that has
John Criswell4a3327e2005-05-13 22:25:59 +00001902 no specific value. Undefined values may be of any type and be used anywhere
Reid Spencer641f5c92004-12-09 18:13:12 +00001903 a constant is permitted.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001904
Reid Spencer641f5c92004-12-09 18:13:12 +00001905 <p>Undefined values indicate to the compiler that the program is well defined
1906 no matter what value is used, giving the compiler more freedom to optimize.
1907 </p>
Chris Lattner74d3f822004-12-09 17:30:23 +00001908</div>
1909
1910<!-- ======================================================================= -->
1911<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
1912</div>
1913
1914<div class="doc_text">
1915
1916<p>Constant expressions are used to allow expressions involving other constants
1917to be used as constants. Constant expressions may be of any <a
John Criswell4a3327e2005-05-13 22:25:59 +00001918href="#t_firstclass">first class</a> type and may involve any LLVM operation
Chris Lattner74d3f822004-12-09 17:30:23 +00001919that does not have side effects (e.g. load and call are not supported). The
1920following is the syntax for constant expressions:</p>
1921
1922<dl>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001923 <dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
1924 <dd>Truncate a constant to another type. The bit size of CST must be larger
Chris Lattnerc0f423a2007-01-15 01:54:13 +00001925 than the bit size of TYPE. Both types must be integers.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +00001926
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001927 <dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
1928 <dd>Zero extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +00001929 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001930
1931 <dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
1932 <dd>Sign extend a constant to another type. The bit size of CST must be
Chris Lattnerc0f423a2007-01-15 01:54:13 +00001933 smaller or equal to the bit size of TYPE. Both types must be integers.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001934
1935 <dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
1936 <dd>Truncate a floating point constant to another floating point type. The
1937 size of CST must be larger than the size of TYPE. Both types must be
1938 floating point.</dd>
1939
1940 <dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
1941 <dd>Floating point extend a constant to another type. The size of CST must be
1942 smaller or equal to the size of TYPE. Both types must be floating point.</dd>
1943
Reid Spencer753163d2007-07-31 14:40:14 +00001944 <dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001945 <dd>Convert a floating point constant to the corresponding unsigned integer
Nate Begemand4d45c22007-11-17 03:58:34 +00001946 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1947 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1948 of the same number of elements. If the value won't fit in the integer type,
1949 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001950
Reid Spencer51b07252006-11-09 23:03:26 +00001951 <dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001952 <dd>Convert a floating point constant to the corresponding signed integer
Nate Begemand4d45c22007-11-17 03:58:34 +00001953 constant. TYPE must be a scalar or vector integer type. CST must be of scalar
1954 or vector floating point type. Both CST and TYPE must be scalars, or vectors
1955 of the same number of elements. If the value won't fit in the integer type,
1956 the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001957
Reid Spencer51b07252006-11-09 23:03:26 +00001958 <dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001959 <dd>Convert an unsigned integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +00001960 constant. TYPE must be a scalar or vector floating point type. CST must be of
1961 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1962 of the same number of elements. If the value won't fit in the floating point
1963 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001964
Reid Spencer51b07252006-11-09 23:03:26 +00001965 <dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001966 <dd>Convert a signed integer constant to the corresponding floating point
Nate Begemand4d45c22007-11-17 03:58:34 +00001967 constant. TYPE must be a scalar or vector floating point type. CST must be of
1968 scalar or vector integer type. Both CST and TYPE must be scalars, or vectors
1969 of the same number of elements. If the value won't fit in the floating point
1970 type, the results are undefined.</dd>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00001971
Reid Spencer5b950642006-11-11 23:08:07 +00001972 <dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
1973 <dd>Convert a pointer typed constant to the corresponding integer constant
1974 TYPE must be an integer type. CST must be of pointer type. The CST value is
1975 zero extended, truncated, or unchanged to make it fit in TYPE.</dd>
1976
1977 <dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
1978 <dd>Convert a integer constant to a pointer constant. TYPE must be a
1979 pointer type. CST must be of integer type. The CST value is zero extended,
1980 truncated, or unchanged to make it fit in a pointer size. This one is
1981 <i>really</i> dangerous!</dd>
1982
1983 <dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner789dee32009-02-28 18:27:03 +00001984 <dd>Convert a constant, CST, to another TYPE. The constraints of the operands
1985 are the same as those for the <a href="#i_bitcast">bitcast
1986 instruction</a>.</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +00001987
1988 <dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
1989
1990 <dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
1991 constants. As with the <a href="#i_getelementptr">getelementptr</a>
1992 instruction, the index list may have zero or more indexes, which are required
1993 to make sense for the type of "CSTPTR".</dd>
1994
Robert Bocchino7e97a6d2006-01-10 19:31:34 +00001995 <dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
1996
1997 <dd>Perform the <a href="#i_select">select operation</a> on
Reid Spencer9965ee72006-12-04 19:23:19 +00001998 constants.</dd>
1999
2000 <dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
2001 <dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
2002
2003 <dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
2004 <dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +00002005
Nate Begemand2195702008-05-12 19:01:56 +00002006 <dt><b><tt>vicmp COND ( VAL1, VAL2 )</tt></b></dt>
2007 <dd>Performs the <a href="#i_vicmp">vicmp operation</a> on constants.</dd>
2008
2009 <dt><b><tt>vfcmp COND ( VAL1, VAL2 )</tt></b></dt>
2010 <dd>Performs the <a href="#i_vfcmp">vfcmp operation</a> on constants.</dd>
2011
Robert Bocchino7e97a6d2006-01-10 19:31:34 +00002012 <dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
2013
2014 <dd>Perform the <a href="#i_extractelement">extractelement
Dan Gohmanef9462f2008-10-14 16:51:45 +00002015 operation</a> on constants.</dd>
Robert Bocchino7e97a6d2006-01-10 19:31:34 +00002016
Robert Bocchinof72fdfe2006-01-15 20:48:27 +00002017 <dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
2018
2019 <dd>Perform the <a href="#i_insertelement">insertelement
Reid Spencer9965ee72006-12-04 19:23:19 +00002020 operation</a> on constants.</dd>
Robert Bocchinof72fdfe2006-01-15 20:48:27 +00002021
Chris Lattner016a0e52006-04-08 00:13:41 +00002022
2023 <dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
2024
2025 <dd>Perform the <a href="#i_shufflevector">shufflevector
Reid Spencer9965ee72006-12-04 19:23:19 +00002026 operation</a> on constants.</dd>
Chris Lattner016a0e52006-04-08 00:13:41 +00002027
Chris Lattner74d3f822004-12-09 17:30:23 +00002028 <dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
2029
Reid Spencer641f5c92004-12-09 18:13:12 +00002030 <dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
2031 be any of the <a href="#binaryops">binary</a> or <a href="#bitwiseops">bitwise
Chris Lattner74d3f822004-12-09 17:30:23 +00002032 binary</a> operations. The constraints on operands are the same as those for
2033 the corresponding instruction (e.g. no bitwise operations on floating point
John Criswell02fdc6f2005-05-12 16:52:32 +00002034 values are allowed).</dd>
Chris Lattner74d3f822004-12-09 17:30:23 +00002035</dl>
Chris Lattner74d3f822004-12-09 17:30:23 +00002036</div>
Chris Lattnerb1652612004-03-08 16:49:10 +00002037
Nick Lewycky49f89192009-04-04 07:22:01 +00002038<!-- ======================================================================= -->
2039<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
2040</div>
2041
2042<div class="doc_text">
2043
2044<p>Embedded metadata provides a way to attach arbitrary data to the
2045instruction stream without affecting the behaviour of the program. There are
2046two metadata primitives, strings and nodes. All metadata has the type of an
2047empty struct and is identified in syntax by a preceding exclamation point
2048('<tt>!</tt>').
2049</p>
2050
2051<p>A metadata string is a string surrounded by double quotes. It can contain
2052any character by escaping non-printable characters with "\xx" where "xx" is
2053the two digit hex code. For example: "<tt>!"test\00"</tt>".
2054</p>
2055
2056<p>Metadata nodes are represented with notation similar to structure constants
2057(a comma separated list of elements, surrounded by braces and preceeded by an
2058exclamation point). For example: "<tt>!{ { } !"test\00", i32 10}</tt>".
2059</p>
2060
2061<p>Optimizations may rely on metadata to provide additional information about
2062the program that isn't available in the instructions, or that isn't easily
2063computable. Similarly, the code generator may expect a certain metadata format
2064to be used to express debugging information.</p>
2065</div>
2066
Chris Lattner2f7c9632001-06-06 20:29:01 +00002067<!-- *********************************************************************** -->
Chris Lattner98f013c2006-01-25 23:47:57 +00002068<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
2069<!-- *********************************************************************** -->
2070
2071<!-- ======================================================================= -->
2072<div class="doc_subsection">
2073<a name="inlineasm">Inline Assembler Expressions</a>
2074</div>
2075
2076<div class="doc_text">
2077
2078<p>
2079LLVM supports inline assembler expressions (as opposed to <a href="#moduleasm">
2080Module-Level Inline Assembly</a>) through the use of a special value. This
2081value represents the inline assembler as a string (containing the instructions
2082to emit), a list of operand constraints (stored as a string), and a flag that
2083indicates whether or not the inline asm expression has side effects. An example
2084inline assembler expression is:
2085</p>
2086
Bill Wendling3716c5d2007-05-29 09:04:49 +00002087<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +00002088<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00002089i32 (i32) asm "bswap $0", "=r,r"
Chris Lattner98f013c2006-01-25 23:47:57 +00002090</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00002091</div>
Chris Lattner98f013c2006-01-25 23:47:57 +00002092
2093<p>
2094Inline assembler expressions may <b>only</b> be used as the callee operand of
2095a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we have:
2096</p>
2097
Bill Wendling3716c5d2007-05-29 09:04:49 +00002098<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +00002099<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00002100%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
Chris Lattner98f013c2006-01-25 23:47:57 +00002101</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00002102</div>
Chris Lattner98f013c2006-01-25 23:47:57 +00002103
2104<p>
2105Inline asms with side effects not visible in the constraint list must be marked
2106as having side effects. This is done through the use of the
2107'<tt>sideeffect</tt>' keyword, like so:
2108</p>
2109
Bill Wendling3716c5d2007-05-29 09:04:49 +00002110<div class="doc_code">
Chris Lattner98f013c2006-01-25 23:47:57 +00002111<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00002112call void asm sideeffect "eieio", ""()
Chris Lattner98f013c2006-01-25 23:47:57 +00002113</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00002114</div>
Chris Lattner98f013c2006-01-25 23:47:57 +00002115
2116<p>TODO: The format of the asm and constraints string still need to be
2117documented here. Constraints on what can be done (e.g. duplication, moving, etc
Chris Lattnerd5528262008-10-04 18:36:02 +00002118need to be documented). This is probably best done by reference to another
2119document that covers inline asm from a holistic perspective.
Chris Lattner98f013c2006-01-25 23:47:57 +00002120</p>
2121
2122</div>
2123
2124<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002125<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
2126<!-- *********************************************************************** -->
Chris Lattner74d3f822004-12-09 17:30:23 +00002127
Misha Brukman76307852003-11-08 01:05:38 +00002128<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +00002129
Chris Lattner48b383b02003-11-25 01:02:51 +00002130<p>The LLVM instruction set consists of several different
2131classifications of instructions: <a href="#terminators">terminator
John Criswell4a3327e2005-05-13 22:25:59 +00002132instructions</a>, <a href="#binaryops">binary instructions</a>,
2133<a href="#bitwiseops">bitwise binary instructions</a>, <a
Chris Lattner48b383b02003-11-25 01:02:51 +00002134 href="#memoryops">memory instructions</a>, and <a href="#otherops">other
2135instructions</a>.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00002136
Misha Brukman76307852003-11-08 01:05:38 +00002137</div>
Chris Lattner74d3f822004-12-09 17:30:23 +00002138
Chris Lattner2f7c9632001-06-06 20:29:01 +00002139<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002140<div class="doc_subsection"> <a name="terminators">Terminator
2141Instructions</a> </div>
Chris Lattner74d3f822004-12-09 17:30:23 +00002142
Misha Brukman76307852003-11-08 01:05:38 +00002143<div class="doc_text">
Chris Lattner74d3f822004-12-09 17:30:23 +00002144
Chris Lattner48b383b02003-11-25 01:02:51 +00002145<p>As mentioned <a href="#functionstructure">previously</a>, every
2146basic block in a program ends with a "Terminator" instruction, which
2147indicates which block should be executed after the current block is
2148finished. These terminator instructions typically yield a '<tt>void</tt>'
2149value: they produce control flow, not values (the one exception being
2150the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
John Criswelldfe6a862004-12-10 15:51:16 +00002151<p>There are six different terminator instructions: the '<a
Chris Lattner48b383b02003-11-25 01:02:51 +00002152 href="#i_ret"><tt>ret</tt></a>' instruction, the '<a href="#i_br"><tt>br</tt></a>'
2153instruction, the '<a href="#i_switch"><tt>switch</tt></a>' instruction,
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002154the '<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the '<a
2155 href="#i_unwind"><tt>unwind</tt></a>' instruction, and the '<a
2156 href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Chris Lattner74d3f822004-12-09 17:30:23 +00002157
Misha Brukman76307852003-11-08 01:05:38 +00002158</div>
Chris Lattner74d3f822004-12-09 17:30:23 +00002159
Chris Lattner2f7c9632001-06-06 20:29:01 +00002160<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002161<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
2162Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00002163<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00002164<h5>Syntax:</h5>
Dan Gohmancc3132e2008-10-04 19:00:07 +00002165<pre>
2166 ret &lt;type&gt; &lt;value&gt; <i>; Return a value from a non-void function</i>
Chris Lattner590645f2002-04-14 06:13:44 +00002167 ret void <i>; Return from void function</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002168</pre>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002169
Chris Lattner2f7c9632001-06-06 20:29:01 +00002170<h5>Overview:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002171
Dan Gohmancc3132e2008-10-04 19:00:07 +00002172<p>The '<tt>ret</tt>' instruction is used to return control flow (and
2173optionally a value) from a function back to the caller.</p>
John Criswell417228d2004-04-09 16:48:45 +00002174<p>There are two forms of the '<tt>ret</tt>' instruction: one that
Dan Gohmancc3132e2008-10-04 19:00:07 +00002175returns a value and then causes control flow, and one that just causes
Chris Lattner48b383b02003-11-25 01:02:51 +00002176control flow to occur.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002177
Chris Lattner2f7c9632001-06-06 20:29:01 +00002178<h5>Arguments:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002179
Dan Gohmancc3132e2008-10-04 19:00:07 +00002180<p>The '<tt>ret</tt>' instruction optionally accepts a single argument,
2181the return value. The type of the return value must be a
2182'<a href="#t_firstclass">first class</a>' type.</p>
2183
2184<p>A function is not <a href="#wellformed">well formed</a> if
2185it it has a non-void return type and contains a '<tt>ret</tt>'
2186instruction with no return value or a return value with a type that
2187does not match its type, or if it has a void return type and contains
2188a '<tt>ret</tt>' instruction with a return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002189
Chris Lattner2f7c9632001-06-06 20:29:01 +00002190<h5>Semantics:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002191
Chris Lattner48b383b02003-11-25 01:02:51 +00002192<p>When the '<tt>ret</tt>' instruction is executed, control flow
2193returns back to the calling function's context. If the caller is a "<a
John Criswell40db33f2004-06-25 15:16:57 +00002194 href="#i_call"><tt>call</tt></a>" instruction, execution continues at
Chris Lattner48b383b02003-11-25 01:02:51 +00002195the instruction after the call. If the caller was an "<a
2196 href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues
John Criswell02fdc6f2005-05-12 16:52:32 +00002197at the beginning of the "normal" destination block. If the instruction
Chris Lattner48b383b02003-11-25 01:02:51 +00002198returns a value, that value shall set the call or invoke instruction's
Dan Gohmanef9462f2008-10-14 16:51:45 +00002199return value.</p>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002200
Chris Lattner2f7c9632001-06-06 20:29:01 +00002201<h5>Example:</h5>
Chris Lattnerda508ac2008-04-23 04:59:35 +00002202
2203<pre>
2204 ret i32 5 <i>; Return an integer value of 5</i>
Chris Lattner590645f2002-04-14 06:13:44 +00002205 ret void <i>; Return from a void function</i>
Bill Wendling050ee8f2009-02-28 22:12:54 +00002206 ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002207</pre>
Dan Gohman3065b612009-01-12 23:12:39 +00002208
Dan Gohman142ccc02009-01-24 15:58:40 +00002209<p>Note that the code generator does not yet fully support large
2210 return values. The specific sizes that are currently supported are
2211 dependent on the target. For integers, on 32-bit targets the limit
2212 is often 64 bits, and on 64-bit targets the limit is often 128 bits.
2213 For aggregate types, the current limits are dependent on the element
2214 types; for example targets are often limited to 2 total integer
2215 elements and 2 total floating-point elements.</p>
Dan Gohman3065b612009-01-12 23:12:39 +00002216
Misha Brukman76307852003-11-08 01:05:38 +00002217</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002218<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002219<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00002220<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00002221<h5>Syntax:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +00002222<pre> br i1 &lt;cond&gt;, label &lt;iftrue&gt;, label &lt;iffalse&gt;<br> br label &lt;dest&gt; <i>; Unconditional branch</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002223</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002224<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00002225<p>The '<tt>br</tt>' instruction is used to cause control flow to
2226transfer to a different basic block in the current function. There are
2227two forms of this instruction, corresponding to a conditional branch
2228and an unconditional branch.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002229<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00002230<p>The conditional branch form of the '<tt>br</tt>' instruction takes a
Reid Spencer36a15422007-01-12 03:35:51 +00002231single '<tt>i1</tt>' value and two '<tt>label</tt>' values. The
Reid Spencer50c723a2007-02-19 23:54:10 +00002232unconditional form of the '<tt>br</tt>' instruction takes a single
2233'<tt>label</tt>' value as a target.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002234<h5>Semantics:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +00002235<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +00002236argument is evaluated. If the value is <tt>true</tt>, control flows
2237to the '<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
2238control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002239<h5>Example:</h5>
Reid Spencer36a15422007-01-12 03:35:51 +00002240<pre>Test:<br> %cond = <a href="#i_icmp">icmp</a> eq, i32 %a, %b<br> br i1 %cond, label %IfEqual, label %IfUnequal<br>IfEqual:<br> <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002241 href="#i_ret">ret</a> i32 1<br>IfUnequal:<br> <a href="#i_ret">ret</a> i32 0<br></pre>
Misha Brukman76307852003-11-08 01:05:38 +00002242</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002243<!-- _______________________________________________________________________ -->
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002244<div class="doc_subsubsection">
2245 <a name="i_switch">'<tt>switch</tt>' Instruction</a>
2246</div>
2247
Misha Brukman76307852003-11-08 01:05:38 +00002248<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00002249<h5>Syntax:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002250
2251<pre>
2252 switch &lt;intty&gt; &lt;value&gt;, label &lt;defaultdest&gt; [ &lt;intty&gt; &lt;val&gt;, label &lt;dest&gt; ... ]
2253</pre>
2254
Chris Lattner2f7c9632001-06-06 20:29:01 +00002255<h5>Overview:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002256
2257<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
2258several different places. It is a generalization of the '<tt>br</tt>'
Misha Brukman76307852003-11-08 01:05:38 +00002259instruction, allowing a branch to occur to one of many possible
2260destinations.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002261
2262
Chris Lattner2f7c9632001-06-06 20:29:01 +00002263<h5>Arguments:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002264
2265<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
2266comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination, and
2267an array of pairs of comparison value constants and '<tt>label</tt>'s. The
2268table is not allowed to contain duplicate constant entries.</p>
2269
Chris Lattner2f7c9632001-06-06 20:29:01 +00002270<h5>Semantics:</h5>
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002271
Chris Lattner48b383b02003-11-25 01:02:51 +00002272<p>The <tt>switch</tt> instruction specifies a table of values and
2273destinations. When the '<tt>switch</tt>' instruction is executed, this
John Criswellbcbb18c2004-06-25 16:05:06 +00002274table is searched for the given value. If the value is found, control flow is
2275transfered to the corresponding destination; otherwise, control flow is
2276transfered to the default destination.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002277
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002278<h5>Implementation:</h5>
2279
2280<p>Depending on properties of the target machine and the particular
2281<tt>switch</tt> instruction, this instruction may be code generated in different
John Criswellbcbb18c2004-06-25 16:05:06 +00002282ways. For example, it could be generated as a series of chained conditional
2283branches or with a lookup table.</p>
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002284
2285<h5>Example:</h5>
2286
2287<pre>
2288 <i>; Emulate a conditional br instruction</i>
Reid Spencer36a15422007-01-12 03:35:51 +00002289 %Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman623806e2009-01-04 23:44:43 +00002290 switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002291
2292 <i>; Emulate an unconditional br instruction</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002293 switch i32 0, label %dest [ ]
Chris Lattnercf96c6c2004-02-24 04:54:45 +00002294
2295 <i>; Implement a jump table:</i>
Dan Gohman623806e2009-01-04 23:44:43 +00002296 switch i32 %val, label %otherwise [ i32 0, label %onzero
2297 i32 1, label %onone
2298 i32 2, label %ontwo ]
Chris Lattner2f7c9632001-06-06 20:29:01 +00002299</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002300</div>
Chris Lattner0132aff2005-05-06 22:57:40 +00002301
Chris Lattner2f7c9632001-06-06 20:29:01 +00002302<!-- _______________________________________________________________________ -->
Chris Lattner0132aff2005-05-06 22:57:40 +00002303<div class="doc_subsubsection">
2304 <a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
2305</div>
2306
Misha Brukman76307852003-11-08 01:05:38 +00002307<div class="doc_text">
Chris Lattner0132aff2005-05-06 22:57:40 +00002308
Chris Lattner2f7c9632001-06-06 20:29:01 +00002309<h5>Syntax:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +00002310
2311<pre>
Devang Patel02256232008-10-07 17:48:33 +00002312 &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 +00002313 to label &lt;normal label&gt; unwind label &lt;exception label&gt;
Chris Lattner0132aff2005-05-06 22:57:40 +00002314</pre>
2315
Chris Lattnera8292f32002-05-06 22:08:29 +00002316<h5>Overview:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +00002317
2318<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
2319function, with the possibility of control flow transfer to either the
John Criswell02fdc6f2005-05-12 16:52:32 +00002320'<tt>normal</tt>' label or the
2321'<tt>exception</tt>' label. If the callee function returns with the
Chris Lattner0132aff2005-05-06 22:57:40 +00002322"<tt><a href="#i_ret">ret</a></tt>" instruction, control flow will return to the
2323"normal" label. If the callee (or any indirect callees) returns with the "<a
John Criswell02fdc6f2005-05-12 16:52:32 +00002324href="#i_unwind"><tt>unwind</tt></a>" instruction, control is interrupted and
Dan Gohmanef9462f2008-10-14 16:51:45 +00002325continued at the dynamically nearest "exception" label.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +00002326
Chris Lattner2f7c9632001-06-06 20:29:01 +00002327<h5>Arguments:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +00002328
Misha Brukman76307852003-11-08 01:05:38 +00002329<p>This instruction requires several arguments:</p>
Chris Lattner0132aff2005-05-06 22:57:40 +00002330
Chris Lattner2f7c9632001-06-06 20:29:01 +00002331<ol>
Chris Lattner0132aff2005-05-06 22:57:40 +00002332 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +00002333 The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +00002334 convention</a> the call should use. If none is specified, the call defaults
2335 to using C calling conventions.
2336 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +00002337
2338 <li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
2339 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
2340 and '<tt>inreg</tt>' attributes are valid here.</li>
2341
Chris Lattner0132aff2005-05-06 22:57:40 +00002342 <li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
2343 function value being invoked. In most cases, this is a direct function
2344 invocation, but indirect <tt>invoke</tt>s are just as possible, branching off
2345 an arbitrary pointer to function value.
2346 </li>
2347
2348 <li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
2349 function to be invoked. </li>
2350
2351 <li>'<tt>function args</tt>': argument list whose types match the function
2352 signature argument types. If the function signature indicates the function
2353 accepts a variable number of arguments, the extra arguments can be
2354 specified. </li>
2355
2356 <li>'<tt>normal label</tt>': the label reached when the called function
2357 executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
2358
2359 <li>'<tt>exception label</tt>': the label reached when a callee returns with
2360 the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
2361
Devang Patel02256232008-10-07 17:48:33 +00002362 <li>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patel7e9b05e2008-10-06 18:50:38 +00002363 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
2364 '<tt>readnone</tt>' attributes are valid here.</li>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002365</ol>
Chris Lattner0132aff2005-05-06 22:57:40 +00002366
Chris Lattner2f7c9632001-06-06 20:29:01 +00002367<h5>Semantics:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +00002368
Misha Brukman76307852003-11-08 01:05:38 +00002369<p>This instruction is designed to operate as a standard '<tt><a
Chris Lattner0132aff2005-05-06 22:57:40 +00002370href="#i_call">call</a></tt>' instruction in most regards. The primary
2371difference is that it establishes an association with a label, which is used by
2372the runtime library to unwind the stack.</p>
2373
2374<p>This instruction is used in languages with destructors to ensure that proper
2375cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
2376exception. Additionally, this is important for implementation of
2377'<tt>catch</tt>' clauses in high-level languages that support them.</p>
2378
Chris Lattner2f7c9632001-06-06 20:29:01 +00002379<h5>Example:</h5>
Chris Lattner0132aff2005-05-06 22:57:40 +00002380<pre>
Nick Lewycky084ab472008-03-16 07:18:12 +00002381 %retval = invoke i32 @Test(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +00002382 unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky084ab472008-03-16 07:18:12 +00002383 %retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Jeff Cohen5819f182007-04-22 01:17:39 +00002384 unwind label %TestCleanup <i>; {i32}:retval set</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002385</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002386</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002387
2388
Chris Lattner5ed60612003-09-03 00:41:47 +00002389<!-- _______________________________________________________________________ -->
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002390
Chris Lattner48b383b02003-11-25 01:02:51 +00002391<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
2392Instruction</a> </div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002393
Misha Brukman76307852003-11-08 01:05:38 +00002394<div class="doc_text">
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002395
Chris Lattner5ed60612003-09-03 00:41:47 +00002396<h5>Syntax:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002397<pre>
2398 unwind
2399</pre>
2400
Chris Lattner5ed60612003-09-03 00:41:47 +00002401<h5>Overview:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002402
2403<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
2404at the first callee in the dynamic call stack which used an <a
2405href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call. This is
2406primarily used to implement exception handling.</p>
2407
Chris Lattner5ed60612003-09-03 00:41:47 +00002408<h5>Semantics:</h5>
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002409
Chris Lattnerfe8519c2008-04-19 21:01:16 +00002410<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002411immediately halt. The dynamic call stack is then searched for the first <a
2412href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack. Once found,
2413execution continues at the "exceptional" destination block specified by the
2414<tt>invoke</tt> instruction. If there is no <tt>invoke</tt> instruction in the
2415dynamic call chain, undefined behavior results.</p>
Misha Brukman76307852003-11-08 01:05:38 +00002416</div>
Chris Lattner08b7d5b2004-10-16 18:04:13 +00002417
2418<!-- _______________________________________________________________________ -->
2419
2420<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
2421Instruction</a> </div>
2422
2423<div class="doc_text">
2424
2425<h5>Syntax:</h5>
2426<pre>
2427 unreachable
2428</pre>
2429
2430<h5>Overview:</h5>
2431
2432<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
2433instruction is used to inform the optimizer that a particular portion of the
2434code is not reachable. This can be used to indicate that the code after a
2435no-return function cannot be reached, and other facts.</p>
2436
2437<h5>Semantics:</h5>
2438
2439<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
2440</div>
2441
2442
2443
Chris Lattner2f7c9632001-06-06 20:29:01 +00002444<!-- ======================================================================= -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002445<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00002446<div class="doc_text">
Chris Lattner48b383b02003-11-25 01:02:51 +00002447<p>Binary operators are used to do most of the computation in a
Chris Lattner81f92972008-04-01 18:47:32 +00002448program. They require two operands of the same type, execute an operation on them, and
John Criswelldfe6a862004-12-10 15:51:16 +00002449produce a single value. The operands might represent
Reid Spencer404a3252007-02-15 03:07:05 +00002450multiple data, as is the case with the <a href="#t_vector">vector</a> data type.
Chris Lattner81f92972008-04-01 18:47:32 +00002451The result value has the same type as its operands.</p>
Misha Brukman76307852003-11-08 01:05:38 +00002452<p>There are several different binary operators:</p>
Misha Brukman76307852003-11-08 01:05:38 +00002453</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002454<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002455<div class="doc_subsubsection">
2456 <a name="i_add">'<tt>add</tt>' Instruction</a>
2457</div>
2458
Misha Brukman76307852003-11-08 01:05:38 +00002459<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002460
Chris Lattner2f7c9632001-06-06 20:29:01 +00002461<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002462
2463<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002464 &lt;result&gt; = add &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002465</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002466
Chris Lattner2f7c9632001-06-06 20:29:01 +00002467<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002468
Misha Brukman76307852003-11-08 01:05:38 +00002469<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002470
Chris Lattner2f7c9632001-06-06 20:29:01 +00002471<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002472
2473<p>The two arguments to the '<tt>add</tt>' instruction must be <a
2474 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>, or
2475 <a href="#t_vector">vector</a> values. Both arguments must have identical
2476 types.</p>
2477
Chris Lattner2f7c9632001-06-06 20:29:01 +00002478<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002479
Misha Brukman76307852003-11-08 01:05:38 +00002480<p>The value produced is the integer or floating point sum of the two
2481operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002482
Chris Lattner2f2427e2008-01-28 00:36:27 +00002483<p>If an integer sum has unsigned overflow, the result returned is the
2484mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2485the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002486
Chris Lattner2f2427e2008-01-28 00:36:27 +00002487<p>Because LLVM integers use a two's complement representation, this
2488instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002489
Chris Lattner2f7c9632001-06-06 20:29:01 +00002490<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002491
2492<pre>
2493 &lt;result&gt; = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002494</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002495</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002496<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002497<div class="doc_subsubsection">
2498 <a name="i_sub">'<tt>sub</tt>' Instruction</a>
2499</div>
2500
Misha Brukman76307852003-11-08 01:05:38 +00002501<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002502
Chris Lattner2f7c9632001-06-06 20:29:01 +00002503<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002504
2505<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002506 &lt;result&gt; = sub &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002507</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002508
Chris Lattner2f7c9632001-06-06 20:29:01 +00002509<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002510
Misha Brukman76307852003-11-08 01:05:38 +00002511<p>The '<tt>sub</tt>' instruction returns the difference of its two
2512operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002513
2514<p>Note that the '<tt>sub</tt>' instruction is used to represent the
2515'<tt>neg</tt>' instruction present in most other intermediate
2516representations.</p>
2517
Chris Lattner2f7c9632001-06-06 20:29:01 +00002518<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002519
2520<p>The two arguments to the '<tt>sub</tt>' instruction must be <a
2521 href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2522 or <a href="#t_vector">vector</a> values. Both arguments must have identical
2523 types.</p>
2524
Chris Lattner2f7c9632001-06-06 20:29:01 +00002525<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002526
Chris Lattner48b383b02003-11-25 01:02:51 +00002527<p>The value produced is the integer or floating point difference of
2528the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002529
Chris Lattner2f2427e2008-01-28 00:36:27 +00002530<p>If an integer difference has unsigned overflow, the result returned is the
2531mathematical result modulo 2<sup>n</sup>, where n is the bit width of
2532the result.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002533
Chris Lattner2f2427e2008-01-28 00:36:27 +00002534<p>Because LLVM integers use a two's complement representation, this
2535instruction is appropriate for both signed and unsigned integers.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002536
Chris Lattner2f7c9632001-06-06 20:29:01 +00002537<h5>Example:</h5>
Bill Wendling2d8b9a82007-05-29 09:42:13 +00002538<pre>
2539 &lt;result&gt; = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002540 &lt;result&gt; = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002541</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002542</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002543
Chris Lattner2f7c9632001-06-06 20:29:01 +00002544<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002545<div class="doc_subsubsection">
2546 <a name="i_mul">'<tt>mul</tt>' Instruction</a>
2547</div>
2548
Misha Brukman76307852003-11-08 01:05:38 +00002549<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002550
Chris Lattner2f7c9632001-06-06 20:29:01 +00002551<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002552<pre> &lt;result&gt; = mul &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002553</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002554<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00002555<p>The '<tt>mul</tt>' instruction returns the product of its two
2556operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002557
Chris Lattner2f7c9632001-06-06 20:29:01 +00002558<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002559
2560<p>The two arguments to the '<tt>mul</tt>' instruction must be <a
2561href="#t_integer">integer</a>, <a href="#t_floating">floating point</a>,
2562or <a href="#t_vector">vector</a> values. Both arguments must have identical
2563types.</p>
2564
Chris Lattner2f7c9632001-06-06 20:29:01 +00002565<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002566
Chris Lattner48b383b02003-11-25 01:02:51 +00002567<p>The value produced is the integer or floating point product of the
Misha Brukman76307852003-11-08 01:05:38 +00002568two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002569
Chris Lattner2f2427e2008-01-28 00:36:27 +00002570<p>If the result of an integer multiplication has unsigned overflow,
2571the result returned is the mathematical result modulo
25722<sup>n</sup>, where n is the bit width of the result.</p>
2573<p>Because LLVM integers use a two's complement representation, and the
2574result is the same width as the operands, this instruction returns the
2575correct result for both signed and unsigned integers. If a full product
2576(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands
2577should be sign-extended or zero-extended as appropriate to the
2578width of the full product.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002579<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002580<pre> &lt;result&gt; = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002581</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002582</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002583
Chris Lattner2f7c9632001-06-06 20:29:01 +00002584<!-- _______________________________________________________________________ -->
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002585<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
2586</a></div>
2587<div class="doc_text">
2588<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002589<pre> &lt;result&gt; = udiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002590</pre>
2591<h5>Overview:</h5>
2592<p>The '<tt>udiv</tt>' instruction returns the quotient of its two
2593operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002594
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002595<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002596
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002597<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002598<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2599values. Both arguments must have identical types.</p>
2600
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002601<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002602
Chris Lattner2f2427e2008-01-28 00:36:27 +00002603<p>The value produced is the unsigned integer quotient of the two operands.</p>
2604<p>Note that unsigned integer division and signed integer division are distinct
2605operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
2606<p>Division by zero leads to undefined behavior.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002607<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002608<pre> &lt;result&gt; = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002609</pre>
2610</div>
2611<!-- _______________________________________________________________________ -->
2612<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
2613</a> </div>
2614<div class="doc_text">
2615<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002616<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002617 &lt;result&gt; = sdiv &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002618</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002619
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002620<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002621
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002622<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two
2623operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002624
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002625<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002626
2627<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
2628<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2629values. Both arguments must have identical types.</p>
2630
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002631<h5>Semantics:</h5>
Chris Lattner1429e6f2008-04-01 18:45:27 +00002632<p>The value produced is the signed integer quotient of the two operands rounded towards zero.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +00002633<p>Note that signed integer division and unsigned integer division are distinct
2634operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
2635<p>Division by zero leads to undefined behavior. Overflow also leads to
2636undefined behavior; this is a rare case, but can occur, for example,
2637by doing a 32-bit division of -2147483648 by -1.</p>
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002638<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002639<pre> &lt;result&gt; = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002640</pre>
2641</div>
2642<!-- _______________________________________________________________________ -->
2643<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
Chris Lattner48b383b02003-11-25 01:02:51 +00002644Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00002645<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00002646<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002647<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002648 &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 +00002649</pre>
2650<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002651
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002652<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two
Chris Lattner48b383b02003-11-25 01:02:51 +00002653operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002654
Chris Lattner48b383b02003-11-25 01:02:51 +00002655<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002656
Jeff Cohen5819f182007-04-22 01:17:39 +00002657<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002658<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2659of floating point values. Both arguments must have identical types.</p>
2660
Chris Lattner48b383b02003-11-25 01:02:51 +00002661<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002662
Reid Spencer7e80b0b2006-10-26 06:15:43 +00002663<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002664
Chris Lattner48b383b02003-11-25 01:02:51 +00002665<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002666
2667<pre>
2668 &lt;result&gt; = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +00002669</pre>
2670</div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002671
Chris Lattner48b383b02003-11-25 01:02:51 +00002672<!-- _______________________________________________________________________ -->
Reid Spencer7eb55b32006-11-02 01:53:59 +00002673<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
2674</div>
2675<div class="doc_text">
2676<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002677<pre> &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 +00002678</pre>
2679<h5>Overview:</h5>
2680<p>The '<tt>urem</tt>' instruction returns the remainder from the
2681unsigned division of its two arguments.</p>
2682<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002683<p>The two arguments to the '<tt>urem</tt>' instruction must be
2684<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2685values. Both arguments must have identical types.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +00002686<h5>Semantics:</h5>
2687<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Chris Lattner1429e6f2008-04-01 18:45:27 +00002688This instruction always performs an unsigned division to get the remainder.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +00002689<p>Note that unsigned integer remainder and signed integer remainder are
2690distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
2691<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Reid Spencer7eb55b32006-11-02 01:53:59 +00002692<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002693<pre> &lt;result&gt; = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +00002694</pre>
2695
2696</div>
2697<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002698<div class="doc_subsubsection">
2699 <a name="i_srem">'<tt>srem</tt>' Instruction</a>
2700</div>
2701
Chris Lattner48b383b02003-11-25 01:02:51 +00002702<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002703
Chris Lattner48b383b02003-11-25 01:02:51 +00002704<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002705
2706<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002707 &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 +00002708</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002709
Chris Lattner48b383b02003-11-25 01:02:51 +00002710<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002711
Reid Spencer7eb55b32006-11-02 01:53:59 +00002712<p>The '<tt>srem</tt>' instruction returns the remainder from the
Dan Gohman08143e32007-11-05 23:35:22 +00002713signed division of its two operands. This instruction can also take
2714<a href="#t_vector">vector</a> versions of the values in which case
2715the elements must be integers.</p>
Chris Lattnerb8f816e2008-01-04 04:33:49 +00002716
Chris Lattner48b383b02003-11-25 01:02:51 +00002717<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002718
Reid Spencer7eb55b32006-11-02 01:53:59 +00002719<p>The two arguments to the '<tt>srem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002720<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2721values. Both arguments must have identical types.</p>
2722
Chris Lattner48b383b02003-11-25 01:02:51 +00002723<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002724
Reid Spencer7eb55b32006-11-02 01:53:59 +00002725<p>This instruction returns the <i>remainder</i> of a division (where the result
Gabor Greif0f75ad02008-08-07 21:46:00 +00002726has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
2727operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
Reid Spencer806ad6a2007-03-24 22:23:39 +00002728a value. For more information about the difference, see <a
Chris Lattner48b383b02003-11-25 01:02:51 +00002729 href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
Reid Spencer806ad6a2007-03-24 22:23:39 +00002730Math Forum</a>. For a table of how this is implemented in various languages,
Reid Spencerdb3b93b2007-03-24 22:40:44 +00002731please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
Reid Spencer806ad6a2007-03-24 22:23:39 +00002732Wikipedia: modulo operation</a>.</p>
Chris Lattner2f2427e2008-01-28 00:36:27 +00002733<p>Note that signed integer remainder and unsigned integer remainder are
2734distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
2735<p>Taking the remainder of a division by zero leads to undefined behavior.
2736Overflow also leads to undefined behavior; this is a rare case, but can occur,
2737for example, by taking the remainder of a 32-bit division of -2147483648 by -1.
2738(The remainder doesn't actually overflow, but this rule lets srem be
2739implemented using instructions that return both the result of the division
2740and the remainder.)</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00002741<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002742<pre> &lt;result&gt; = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Reid Spencer7eb55b32006-11-02 01:53:59 +00002743</pre>
2744
2745</div>
2746<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002747<div class="doc_subsubsection">
2748 <a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
2749
Reid Spencer7eb55b32006-11-02 01:53:59 +00002750<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002751
Reid Spencer7eb55b32006-11-02 01:53:59 +00002752<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002753<pre> &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 +00002754</pre>
2755<h5>Overview:</h5>
2756<p>The '<tt>frem</tt>' instruction returns the remainder from the
2757division of its two operands.</p>
2758<h5>Arguments:</h5>
2759<p>The two arguments to the '<tt>frem</tt>' instruction must be
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002760<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a>
2761of floating point values. Both arguments must have identical types.</p>
2762
Reid Spencer7eb55b32006-11-02 01:53:59 +00002763<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002764
Chris Lattner1429e6f2008-04-01 18:45:27 +00002765<p>This instruction returns the <i>remainder</i> of a division.
2766The remainder has the same sign as the dividend.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002767
Reid Spencer7eb55b32006-11-02 01:53:59 +00002768<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002769
2770<pre>
2771 &lt;result&gt; = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Chris Lattner48b383b02003-11-25 01:02:51 +00002772</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002773</div>
Robert Bocchino820bc75b2006-02-17 21:18:08 +00002774
Reid Spencer2ab01932007-02-02 13:57:07 +00002775<!-- ======================================================================= -->
2776<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
2777Operations</a> </div>
2778<div class="doc_text">
2779<p>Bitwise binary operators are used to do various forms of
2780bit-twiddling in a program. They are generally very efficient
2781instructions and can commonly be strength reduced from other
Chris Lattner1429e6f2008-04-01 18:45:27 +00002782instructions. They require two operands of the same type, execute an operation on them,
2783and produce a single value. The resulting value is the same type as its operands.</p>
Reid Spencer2ab01932007-02-02 13:57:07 +00002784</div>
2785
Reid Spencer04e259b2007-01-31 21:39:12 +00002786<!-- _______________________________________________________________________ -->
2787<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
2788Instruction</a> </div>
2789<div class="doc_text">
2790<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002791<pre> &lt;result&gt; = shl &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +00002792</pre>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002793
Reid Spencer04e259b2007-01-31 21:39:12 +00002794<h5>Overview:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002795
Reid Spencer04e259b2007-01-31 21:39:12 +00002796<p>The '<tt>shl</tt>' instruction returns the first operand shifted to
2797the left a specified number of bits.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002798
Reid Spencer04e259b2007-01-31 21:39:12 +00002799<h5>Arguments:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002800
Reid Spencer04e259b2007-01-31 21:39:12 +00002801<p>Both arguments to the '<tt>shl</tt>' instruction must be the same <a
Nate Begemanfecbc8c2008-07-29 15:49:41 +00002802 href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greif0f75ad02008-08-07 21:46:00 +00002803type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002804
Reid Spencer04e259b2007-01-31 21:39:12 +00002805<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002806
Gabor Greif0f75ad02008-08-07 21:46:00 +00002807<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod 2<sup>n</sup>,
2808where n is the width of the result. If <tt>op2</tt> is (statically or dynamically) negative or
Mon P Wang68d4eee2008-12-10 08:55:09 +00002809equal to or larger than the number of bits in <tt>op1</tt>, the result is undefined.
2810If the arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2811corresponding shift amount in <tt>op2</tt>.</p>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002812
Reid Spencer04e259b2007-01-31 21:39:12 +00002813<h5>Example:</h5><pre>
2814 &lt;result&gt; = shl i32 4, %var <i>; yields {i32}: 4 &lt;&lt; %var</i>
2815 &lt;result&gt; = shl i32 4, 2 <i>; yields {i32}: 16</i>
2816 &lt;result&gt; = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002817 &lt;result&gt; = shl i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +00002818 &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 +00002819</pre>
2820</div>
2821<!-- _______________________________________________________________________ -->
2822<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
2823Instruction</a> </div>
2824<div class="doc_text">
2825<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002826<pre> &lt;result&gt; = lshr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +00002827</pre>
2828
2829<h5>Overview:</h5>
2830<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +00002831operand shifted to the right a specified number of bits with zero fill.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +00002832
2833<h5>Arguments:</h5>
2834<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Nate Begemanfecbc8c2008-07-29 15:49:41 +00002835<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greif0f75ad02008-08-07 21:46:00 +00002836type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +00002837
2838<h5>Semantics:</h5>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002839
Reid Spencer04e259b2007-01-31 21:39:12 +00002840<p>This instruction always performs a logical shift right operation. The most
2841significant bits of the result will be filled with zero bits after the
Gabor Greif0f75ad02008-08-07 21:46:00 +00002842shift. If <tt>op2</tt> is (statically or dynamically) equal to or larger than
Mon P Wang68d4eee2008-12-10 08:55:09 +00002843the number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
2844vectors, each vector element of <tt>op1</tt> is shifted by the corresponding shift
2845amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +00002846
2847<h5>Example:</h5>
2848<pre>
2849 &lt;result&gt; = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
2850 &lt;result&gt; = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
2851 &lt;result&gt; = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
2852 &lt;result&gt; = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002853 &lt;result&gt; = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +00002854 &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 +00002855</pre>
2856</div>
2857
Reid Spencer2ab01932007-02-02 13:57:07 +00002858<!-- _______________________________________________________________________ -->
Reid Spencer04e259b2007-01-31 21:39:12 +00002859<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
2860Instruction</a> </div>
2861<div class="doc_text">
2862
2863<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002864<pre> &lt;result&gt; = ashr &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Reid Spencer04e259b2007-01-31 21:39:12 +00002865</pre>
2866
2867<h5>Overview:</h5>
2868<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
Jeff Cohen5819f182007-04-22 01:17:39 +00002869operand shifted to the right a specified number of bits with sign extension.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +00002870
2871<h5>Arguments:</h5>
2872<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Nate Begemanfecbc8c2008-07-29 15:49:41 +00002873<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
Gabor Greif0f75ad02008-08-07 21:46:00 +00002874type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +00002875
2876<h5>Semantics:</h5>
2877<p>This instruction always performs an arithmetic shift right operation,
2878The most significant bits of the result will be filled with the sign bit
Gabor Greif0f75ad02008-08-07 21:46:00 +00002879of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
Mon P Wang68d4eee2008-12-10 08:55:09 +00002880larger than the number of bits in <tt>op1</tt>, the result is undefined. If the
2881arguments are vectors, each vector element of <tt>op1</tt> is shifted by the
2882corresponding shift amount in <tt>op2</tt>.</p>
Reid Spencer04e259b2007-01-31 21:39:12 +00002883
2884<h5>Example:</h5>
2885<pre>
2886 &lt;result&gt; = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
2887 &lt;result&gt; = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
2888 &lt;result&gt; = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
2889 &lt;result&gt; = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattnerf0e50112007-10-03 21:01:14 +00002890 &lt;result&gt; = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang4dd832d2008-12-09 05:46:39 +00002891 &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 +00002892</pre>
2893</div>
2894
Chris Lattner2f7c9632001-06-06 20:29:01 +00002895<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002896<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
2897Instruction</a> </div>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002898
Misha Brukman76307852003-11-08 01:05:38 +00002899<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002900
Chris Lattner2f7c9632001-06-06 20:29:01 +00002901<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002902
2903<pre>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002904 &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 +00002905</pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002906
Chris Lattner2f7c9632001-06-06 20:29:01 +00002907<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002908
Chris Lattner48b383b02003-11-25 01:02:51 +00002909<p>The '<tt>and</tt>' instruction returns the bitwise logical and of
2910its two operands.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002911
Chris Lattner2f7c9632001-06-06 20:29:01 +00002912<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002913
2914<p>The two arguments to the '<tt>and</tt>' instruction must be
2915<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2916values. Both arguments must have identical types.</p>
2917
Chris Lattner2f7c9632001-06-06 20:29:01 +00002918<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +00002919<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00002920<p> </p>
Bill Wendling5703c6e2008-09-07 10:29:20 +00002921<div>
Misha Brukman76307852003-11-08 01:05:38 +00002922<table border="1" cellspacing="0" cellpadding="4">
Chris Lattner48b383b02003-11-25 01:02:51 +00002923 <tbody>
2924 <tr>
2925 <td>In0</td>
2926 <td>In1</td>
2927 <td>Out</td>
2928 </tr>
2929 <tr>
2930 <td>0</td>
2931 <td>0</td>
2932 <td>0</td>
2933 </tr>
2934 <tr>
2935 <td>0</td>
2936 <td>1</td>
2937 <td>0</td>
2938 </tr>
2939 <tr>
2940 <td>1</td>
2941 <td>0</td>
2942 <td>0</td>
2943 </tr>
2944 <tr>
2945 <td>1</td>
2946 <td>1</td>
2947 <td>1</td>
2948 </tr>
2949 </tbody>
2950</table>
Misha Brukmanc501f552004-03-01 17:47:27 +00002951</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002952<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002953<pre>
2954 &lt;result&gt; = and i32 4, %var <i>; yields {i32}:result = 4 &amp; %var</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00002955 &lt;result&gt; = and i32 15, 40 <i>; yields {i32}:result = 8</i>
2956 &lt;result&gt; = and i32 4, 8 <i>; yields {i32}:result = 0</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002957</pre>
Misha Brukman76307852003-11-08 01:05:38 +00002958</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002959<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00002960<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00002961<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00002962<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00002963<pre> &lt;result&gt; = or &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002964</pre>
Chris Lattner48b383b02003-11-25 01:02:51 +00002965<h5>Overview:</h5>
2966<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive
2967or of its two operands.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002968<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00002969
2970<p>The two arguments to the '<tt>or</tt>' instruction must be
2971<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
2972values. Both arguments must have identical types.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00002973<h5>Semantics:</h5>
Misha Brukman76307852003-11-08 01:05:38 +00002974<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00002975<p> </p>
Bill Wendling5703c6e2008-09-07 10:29:20 +00002976<div>
Chris Lattner48b383b02003-11-25 01:02:51 +00002977<table border="1" cellspacing="0" cellpadding="4">
2978 <tbody>
2979 <tr>
2980 <td>In0</td>
2981 <td>In1</td>
2982 <td>Out</td>
2983 </tr>
2984 <tr>
2985 <td>0</td>
2986 <td>0</td>
2987 <td>0</td>
2988 </tr>
2989 <tr>
2990 <td>0</td>
2991 <td>1</td>
2992 <td>1</td>
2993 </tr>
2994 <tr>
2995 <td>1</td>
2996 <td>0</td>
2997 <td>1</td>
2998 </tr>
2999 <tr>
3000 <td>1</td>
3001 <td>1</td>
3002 <td>1</td>
3003 </tr>
3004 </tbody>
3005</table>
Misha Brukmanc501f552004-03-01 17:47:27 +00003006</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003007<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003008<pre> &lt;result&gt; = or i32 4, %var <i>; yields {i32}:result = 4 | %var</i>
3009 &lt;result&gt; = or i32 15, 40 <i>; yields {i32}:result = 47</i>
3010 &lt;result&gt; = or i32 4, 8 <i>; yields {i32}:result = 12</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003011</pre>
Misha Brukman76307852003-11-08 01:05:38 +00003012</div>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003013<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00003014<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
3015Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00003016<div class="doc_text">
Chris Lattner2f7c9632001-06-06 20:29:01 +00003017<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00003018<pre> &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 +00003019</pre>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003020<h5>Overview:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00003021<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive
3022or of its two operands. The <tt>xor</tt> is used to implement the
3023"one's complement" operation, which is the "~" operator in C.</p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003024<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00003025<p>The two arguments to the '<tt>xor</tt>' instruction must be
3026<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
3027values. Both arguments must have identical types.</p>
3028
Chris Lattner2f7c9632001-06-06 20:29:01 +00003029<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00003030
Misha Brukman76307852003-11-08 01:05:38 +00003031<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00003032<p> </p>
Bill Wendling5703c6e2008-09-07 10:29:20 +00003033<div>
Chris Lattner48b383b02003-11-25 01:02:51 +00003034<table border="1" cellspacing="0" cellpadding="4">
3035 <tbody>
3036 <tr>
3037 <td>In0</td>
3038 <td>In1</td>
3039 <td>Out</td>
3040 </tr>
3041 <tr>
3042 <td>0</td>
3043 <td>0</td>
3044 <td>0</td>
3045 </tr>
3046 <tr>
3047 <td>0</td>
3048 <td>1</td>
3049 <td>1</td>
3050 </tr>
3051 <tr>
3052 <td>1</td>
3053 <td>0</td>
3054 <td>1</td>
3055 </tr>
3056 <tr>
3057 <td>1</td>
3058 <td>1</td>
3059 <td>0</td>
3060 </tr>
3061 </tbody>
3062</table>
Misha Brukmanc501f552004-03-01 17:47:27 +00003063</div>
Chris Lattner48b383b02003-11-25 01:02:51 +00003064<p> </p>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003065<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003066<pre> &lt;result&gt; = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
3067 &lt;result&gt; = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
3068 &lt;result&gt; = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
3069 &lt;result&gt; = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003070</pre>
Misha Brukman76307852003-11-08 01:05:38 +00003071</div>
Chris Lattner54611b42005-11-06 08:02:57 +00003072
Chris Lattner2f7c9632001-06-06 20:29:01 +00003073<!-- ======================================================================= -->
Chris Lattner54611b42005-11-06 08:02:57 +00003074<div class="doc_subsection">
Chris Lattnerce83bff2006-04-08 23:07:04 +00003075 <a name="vectorops">Vector Operations</a>
3076</div>
3077
3078<div class="doc_text">
3079
3080<p>LLVM supports several instructions to represent vector operations in a
Jeff Cohen5819f182007-04-22 01:17:39 +00003081target-independent manner. These instructions cover the element-access and
Chris Lattnerce83bff2006-04-08 23:07:04 +00003082vector-specific operations needed to process vectors effectively. While LLVM
3083does directly support these vector operations, many sophisticated algorithms
3084will want to use target-specific intrinsics to take full advantage of a specific
3085target.</p>
3086
3087</div>
3088
3089<!-- _______________________________________________________________________ -->
3090<div class="doc_subsubsection">
3091 <a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
3092</div>
3093
3094<div class="doc_text">
3095
3096<h5>Syntax:</h5>
3097
3098<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003099 &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 +00003100</pre>
3101
3102<h5>Overview:</h5>
3103
3104<p>
3105The '<tt>extractelement</tt>' instruction extracts a single scalar
Reid Spencer404a3252007-02-15 03:07:05 +00003106element from a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +00003107</p>
3108
3109
3110<h5>Arguments:</h5>
3111
3112<p>
3113The first operand of an '<tt>extractelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +00003114value of <a href="#t_vector">vector</a> type. The second operand is
Chris Lattnerce83bff2006-04-08 23:07:04 +00003115an index indicating the position from which to extract the element.
3116The index may be a variable.</p>
3117
3118<h5>Semantics:</h5>
3119
3120<p>
3121The result is a scalar of the same type as the element type of
3122<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
3123<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
3124results are undefined.
3125</p>
3126
3127<h5>Example:</h5>
3128
3129<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003130 %result = extractelement &lt;4 x i32&gt; %vec, i32 0 <i>; yields i32</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +00003131</pre>
3132</div>
3133
3134
3135<!-- _______________________________________________________________________ -->
3136<div class="doc_subsubsection">
3137 <a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
3138</div>
3139
3140<div class="doc_text">
3141
3142<h5>Syntax:</h5>
3143
3144<pre>
Dan Gohman43ba0672008-05-12 23:38:42 +00003145 &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 +00003146</pre>
3147
3148<h5>Overview:</h5>
3149
3150<p>
3151The '<tt>insertelement</tt>' instruction inserts a scalar
Reid Spencer404a3252007-02-15 03:07:05 +00003152element into a vector at a specified index.
Chris Lattnerce83bff2006-04-08 23:07:04 +00003153</p>
3154
3155
3156<h5>Arguments:</h5>
3157
3158<p>
3159The first operand of an '<tt>insertelement</tt>' instruction is a
Reid Spencer404a3252007-02-15 03:07:05 +00003160value of <a href="#t_vector">vector</a> type. The second operand is a
Chris Lattnerce83bff2006-04-08 23:07:04 +00003161scalar value whose type must equal the element type of the first
3162operand. The third operand is an index indicating the position at
3163which to insert the value. The index may be a variable.</p>
3164
3165<h5>Semantics:</h5>
3166
3167<p>
Reid Spencer404a3252007-02-15 03:07:05 +00003168The result is a vector of the same type as <tt>val</tt>. Its
Chris Lattnerce83bff2006-04-08 23:07:04 +00003169element values are those of <tt>val</tt> except at position
3170<tt>idx</tt>, where it gets the value <tt>elt</tt>. If <tt>idx</tt>
3171exceeds the length of <tt>val</tt>, the results are undefined.
3172</p>
3173
3174<h5>Example:</h5>
3175
3176<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003177 %result = insertelement &lt;4 x i32&gt; %vec, i32 1, i32 0 <i>; yields &lt;4 x i32&gt;</i>
Chris Lattnerce83bff2006-04-08 23:07:04 +00003178</pre>
3179</div>
3180
3181<!-- _______________________________________________________________________ -->
3182<div class="doc_subsubsection">
3183 <a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
3184</div>
3185
3186<div class="doc_text">
3187
3188<h5>Syntax:</h5>
3189
3190<pre>
Mon P Wang25f01062008-11-10 04:46:22 +00003191 &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 +00003192</pre>
3193
3194<h5>Overview:</h5>
3195
3196<p>
3197The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
Mon P Wang25f01062008-11-10 04:46:22 +00003198from two input vectors, returning a vector with the same element type as
3199the input and length that is the same as the shuffle mask.
Chris Lattnerce83bff2006-04-08 23:07:04 +00003200</p>
3201
3202<h5>Arguments:</h5>
3203
3204<p>
Mon P Wang25f01062008-11-10 04:46:22 +00003205The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
3206with types that match each other. The third argument is a shuffle mask whose
3207element type is always 'i32'. The result of the instruction is a vector whose
3208length is the same as the shuffle mask and whose element type is the same as
3209the element type of the first two operands.
Chris Lattnerce83bff2006-04-08 23:07:04 +00003210</p>
3211
3212<p>
3213The shuffle mask operand is required to be a constant vector with either
3214constant integer or undef values.
3215</p>
3216
3217<h5>Semantics:</h5>
3218
3219<p>
3220The elements of the two input vectors are numbered from left to right across
3221both of the vectors. The shuffle mask operand specifies, for each element of
Mon P Wang25f01062008-11-10 04:46:22 +00003222the result vector, which element of the two input vectors the result element
Chris Lattnerce83bff2006-04-08 23:07:04 +00003223gets. The element selector may be undef (meaning "don't care") and the second
3224operand may be undef if performing a shuffle from only one vector.
3225</p>
3226
3227<h5>Example:</h5>
3228
3229<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003230 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
Jeff Cohen5819f182007-04-22 01:17:39 +00003231 &lt;4 x i32&gt; &lt;i32 0, i32 4, i32 1, i32 5&gt; <i>; yields &lt;4 x i32&gt;</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003232 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; undef,
3233 &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.
Mon P Wang25f01062008-11-10 04:46:22 +00003234 %result = shufflevector &lt;8 x i32&gt; %v1, &lt;8 x i32&gt; undef,
3235 &lt;4 x i32&gt; &lt;i32 0, i32 1, i32 2, i32 3&gt; <i>; yields &lt;4 x i32&gt;</i>
3236 %result = shufflevector &lt;4 x i32&gt; %v1, &lt;4 x i32&gt; %v2,
3237 &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 +00003238</pre>
3239</div>
3240
Tanya Lattnerb138bbe2006-04-14 19:24:33 +00003241
Chris Lattnerce83bff2006-04-08 23:07:04 +00003242<!-- ======================================================================= -->
3243<div class="doc_subsection">
Dan Gohmanb9d66602008-05-12 23:51:09 +00003244 <a name="aggregateops">Aggregate Operations</a>
3245</div>
3246
3247<div class="doc_text">
3248
3249<p>LLVM supports several instructions for working with aggregate values.
3250</p>
3251
3252</div>
3253
3254<!-- _______________________________________________________________________ -->
3255<div class="doc_subsubsection">
3256 <a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
3257</div>
3258
3259<div class="doc_text">
3260
3261<h5>Syntax:</h5>
3262
3263<pre>
3264 &lt;result&gt; = extractvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;idx&gt;{, &lt;idx&gt;}*
3265</pre>
3266
3267<h5>Overview:</h5>
3268
3269<p>
Dan Gohman35a835c2008-05-13 18:16:06 +00003270The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
3271or array element from an aggregate value.
Dan Gohmanb9d66602008-05-12 23:51:09 +00003272</p>
3273
3274
3275<h5>Arguments:</h5>
3276
3277<p>
3278The first operand of an '<tt>extractvalue</tt>' instruction is a
3279value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a>
Dan Gohman35a835c2008-05-13 18:16:06 +00003280type. The operands are constant indices to specify which value to extract
Dan Gohman1ecaf452008-05-31 00:58:22 +00003281in a similar manner as indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +00003282'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3283</p>
3284
3285<h5>Semantics:</h5>
3286
3287<p>
3288The result is the value at the position in the aggregate specified by
3289the index operands.
3290</p>
3291
3292<h5>Example:</h5>
3293
3294<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +00003295 %result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +00003296</pre>
3297</div>
3298
3299
3300<!-- _______________________________________________________________________ -->
3301<div class="doc_subsubsection">
3302 <a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
3303</div>
3304
3305<div class="doc_text">
3306
3307<h5>Syntax:</h5>
3308
3309<pre>
Dan Gohman1ecaf452008-05-31 00:58:22 +00003310 &lt;result&gt; = insertvalue &lt;aggregate type&gt; &lt;val&gt;, &lt;ty&gt; &lt;val&gt;, &lt;idx&gt; <i>; yields &lt;n x &lt;ty&gt;&gt;</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +00003311</pre>
3312
3313<h5>Overview:</h5>
3314
3315<p>
3316The '<tt>insertvalue</tt>' instruction inserts a value
Dan Gohman35a835c2008-05-13 18:16:06 +00003317into a struct field or array element in an aggregate.
Dan Gohmanb9d66602008-05-12 23:51:09 +00003318</p>
3319
3320
3321<h5>Arguments:</h5>
3322
3323<p>
3324The first operand of an '<tt>insertvalue</tt>' instruction is a
3325value of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type.
3326The second operand is a first-class value to insert.
Dan Gohman34d1c0d2008-05-23 21:53:15 +00003327The following operands are constant indices
Dan Gohman1ecaf452008-05-31 00:58:22 +00003328indicating the position at which to insert the value in a similar manner as
Dan Gohman35a835c2008-05-13 18:16:06 +00003329indices in a
Dan Gohmanb9d66602008-05-12 23:51:09 +00003330'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.
3331The value to insert must have the same type as the value identified
Dan Gohman35a835c2008-05-13 18:16:06 +00003332by the indices.
Dan Gohmanef9462f2008-10-14 16:51:45 +00003333</p>
Dan Gohmanb9d66602008-05-12 23:51:09 +00003334
3335<h5>Semantics:</h5>
3336
3337<p>
3338The result is an aggregate of the same type as <tt>val</tt>. Its
3339value is that of <tt>val</tt> except that the value at the position
Dan Gohman35a835c2008-05-13 18:16:06 +00003340specified by the indices is that of <tt>elt</tt>.
Dan Gohmanb9d66602008-05-12 23:51:09 +00003341</p>
3342
3343<h5>Example:</h5>
3344
3345<pre>
Dan Gohman88ce1a52008-06-23 15:26:37 +00003346 %result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohmanb9d66602008-05-12 23:51:09 +00003347</pre>
3348</div>
3349
3350
3351<!-- ======================================================================= -->
3352<div class="doc_subsection">
Chris Lattner6ab66722006-08-15 00:45:58 +00003353 <a name="memoryops">Memory Access and Addressing Operations</a>
Chris Lattner54611b42005-11-06 08:02:57 +00003354</div>
3355
Misha Brukman76307852003-11-08 01:05:38 +00003356<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +00003357
Chris Lattner48b383b02003-11-25 01:02:51 +00003358<p>A key design point of an SSA-based representation is how it
3359represents memory. In LLVM, no memory locations are in SSA form, which
3360makes things very simple. This section describes how to read, write,
John Criswelldfe6a862004-12-10 15:51:16 +00003361allocate, and free memory in LLVM.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003362
Misha Brukman76307852003-11-08 01:05:38 +00003363</div>
Chris Lattner54611b42005-11-06 08:02:57 +00003364
Chris Lattner2f7c9632001-06-06 20:29:01 +00003365<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +00003366<div class="doc_subsubsection">
3367 <a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
3368</div>
3369
Misha Brukman76307852003-11-08 01:05:38 +00003370<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +00003371
Chris Lattner2f7c9632001-06-06 20:29:01 +00003372<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003373
3374<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003375 &lt;result&gt; = malloc &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003376</pre>
Chris Lattner54611b42005-11-06 08:02:57 +00003377
Chris Lattner2f7c9632001-06-06 20:29:01 +00003378<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003379
Chris Lattner48b383b02003-11-25 01:02:51 +00003380<p>The '<tt>malloc</tt>' instruction allocates memory from the system
Christopher Lamb55c6d4f2007-12-17 01:00:21 +00003381heap and returns a pointer to it. The object is always allocated in the generic
3382address space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003383
Chris Lattner2f7c9632001-06-06 20:29:01 +00003384<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003385
3386<p>The '<tt>malloc</tt>' instruction allocates
3387<tt>sizeof(&lt;type&gt;)*NumElements</tt>
John Criswella92e5862004-02-24 16:13:56 +00003388bytes of memory from the operating system and returns a pointer of the
Chris Lattner54611b42005-11-06 08:02:57 +00003389appropriate type to the program. If "NumElements" is specified, it is the
Gabor Greifdd1fc982008-02-09 22:24:34 +00003390number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +00003391If a constant alignment is specified, the value result of the allocation is guaranteed to
Gabor Greifdd1fc982008-02-09 22:24:34 +00003392be aligned to at least that boundary. If not specified, or if zero, the target can
3393choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003394
Misha Brukman76307852003-11-08 01:05:38 +00003395<p>'<tt>type</tt>' must be a sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003396
Chris Lattner2f7c9632001-06-06 20:29:01 +00003397<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003398
Chris Lattner48b383b02003-11-25 01:02:51 +00003399<p>Memory is allocated using the system "<tt>malloc</tt>" function, and
Nick Lewyckyf5ffcbc2008-11-24 03:41:24 +00003400a pointer is returned. The result of a zero byte allocation is undefined. The
Chris Lattnerfe8519c2008-04-19 21:01:16 +00003401result is null if there is insufficient memory available.</p>
Misha Brukman76307852003-11-08 01:05:38 +00003402
Chris Lattner54611b42005-11-06 08:02:57 +00003403<h5>Example:</h5>
3404
3405<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +00003406 %array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Chris Lattner54611b42005-11-06 08:02:57 +00003407
Bill Wendling2d8b9a82007-05-29 09:42:13 +00003408 %size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
3409 %array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
3410 %array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
3411 %array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
3412 %array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003413</pre>
Dan Gohman3065b612009-01-12 23:12:39 +00003414
3415<p>Note that the code generator does not yet respect the
3416 alignment value.</p>
3417
Misha Brukman76307852003-11-08 01:05:38 +00003418</div>
Chris Lattner54611b42005-11-06 08:02:57 +00003419
Chris Lattner2f7c9632001-06-06 20:29:01 +00003420<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +00003421<div class="doc_subsubsection">
3422 <a name="i_free">'<tt>free</tt>' Instruction</a>
3423</div>
3424
Misha Brukman76307852003-11-08 01:05:38 +00003425<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +00003426
Chris Lattner2f7c9632001-06-06 20:29:01 +00003427<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003428
3429<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +00003430 free &lt;type&gt; &lt;value&gt; <i>; yields {void}</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003431</pre>
Chris Lattner54611b42005-11-06 08:02:57 +00003432
Chris Lattner2f7c9632001-06-06 20:29:01 +00003433<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003434
Chris Lattner48b383b02003-11-25 01:02:51 +00003435<p>The '<tt>free</tt>' instruction returns memory back to the unused
John Criswell4a3327e2005-05-13 22:25:59 +00003436memory heap to be reallocated in the future.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003437
Chris Lattner2f7c9632001-06-06 20:29:01 +00003438<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003439
Chris Lattner48b383b02003-11-25 01:02:51 +00003440<p>'<tt>value</tt>' shall be a pointer value that points to a value
3441that was allocated with the '<tt><a href="#i_malloc">malloc</a></tt>'
3442instruction.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003443
Chris Lattner2f7c9632001-06-06 20:29:01 +00003444<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003445
John Criswelldfe6a862004-12-10 15:51:16 +00003446<p>Access to the memory pointed to by the pointer is no longer defined
Chris Lattner0f103e12008-04-19 22:41:32 +00003447after this instruction executes. If the pointer is null, the operation
3448is a noop.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003449
Chris Lattner2f7c9632001-06-06 20:29:01 +00003450<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003451
3452<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +00003453 %array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003454 free [4 x i8]* %array
Chris Lattner2f7c9632001-06-06 20:29:01 +00003455</pre>
Misha Brukman76307852003-11-08 01:05:38 +00003456</div>
Chris Lattner54611b42005-11-06 08:02:57 +00003457
Chris Lattner2f7c9632001-06-06 20:29:01 +00003458<!-- _______________________________________________________________________ -->
Chris Lattner54611b42005-11-06 08:02:57 +00003459<div class="doc_subsubsection">
3460 <a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
3461</div>
3462
Misha Brukman76307852003-11-08 01:05:38 +00003463<div class="doc_text">
Chris Lattner54611b42005-11-06 08:02:57 +00003464
Chris Lattner2f7c9632001-06-06 20:29:01 +00003465<h5>Syntax:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003466
3467<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003468 &lt;result&gt; = alloca &lt;type&gt;[, i32 &lt;NumElements&gt;][, align &lt;alignment&gt;] <i>; yields {type*}:result</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003469</pre>
Chris Lattner54611b42005-11-06 08:02:57 +00003470
Chris Lattner2f7c9632001-06-06 20:29:01 +00003471<h5>Overview:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003472
Jeff Cohen5819f182007-04-22 01:17:39 +00003473<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
3474currently executing function, to be automatically released when this function
Christopher Lamb55c6d4f2007-12-17 01:00:21 +00003475returns to its caller. The object is always allocated in the generic address
3476space (address space zero).</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003477
Chris Lattner2f7c9632001-06-06 20:29:01 +00003478<h5>Arguments:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003479
John Criswelldfe6a862004-12-10 15:51:16 +00003480<p>The '<tt>alloca</tt>' instruction allocates <tt>sizeof(&lt;type&gt;)*NumElements</tt>
Chris Lattner48b383b02003-11-25 01:02:51 +00003481bytes of memory on the runtime stack, returning a pointer of the
Gabor Greifdd1fc982008-02-09 22:24:34 +00003482appropriate type to the program. If "NumElements" is specified, it is the
3483number of elements allocated, otherwise "NumElements" is defaulted to be one.
Chris Lattner1f17cce2008-04-02 00:38:26 +00003484If a constant alignment is specified, the value result of the allocation is guaranteed
Gabor Greifdd1fc982008-02-09 22:24:34 +00003485to be aligned to at least that boundary. If not specified, or if zero, the target
3486can choose to align the allocation on any convenient boundary.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003487
Misha Brukman76307852003-11-08 01:05:38 +00003488<p>'<tt>type</tt>' may be any sized type.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003489
Chris Lattner2f7c9632001-06-06 20:29:01 +00003490<h5>Semantics:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003491
Chris Lattnerfe8519c2008-04-19 21:01:16 +00003492<p>Memory is allocated; a pointer is returned. The operation is undefiend if
3493there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
Chris Lattner48b383b02003-11-25 01:02:51 +00003494memory is automatically released when the function returns. The '<tt>alloca</tt>'
3495instruction is commonly used to represent automatic variables that must
3496have an address available. When the function returns (either with the <tt><a
John Criswellc932bef2005-05-12 16:55:34 +00003497 href="#i_ret">ret</a></tt> or <tt><a href="#i_unwind">unwind</a></tt>
Chris Lattner1f17cce2008-04-02 00:38:26 +00003498instructions), the memory is reclaimed. Allocating zero bytes
3499is legal, but the result is undefined.</p>
Chris Lattner54611b42005-11-06 08:02:57 +00003500
Chris Lattner2f7c9632001-06-06 20:29:01 +00003501<h5>Example:</h5>
Chris Lattner54611b42005-11-06 08:02:57 +00003502
3503<pre>
Dan Gohman7a5acb52009-01-04 23:49:44 +00003504 %ptr = alloca i32 <i>; yields {i32*}:ptr</i>
3505 %ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
3506 %ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
3507 %ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Chris Lattner2f7c9632001-06-06 20:29:01 +00003508</pre>
Misha Brukman76307852003-11-08 01:05:38 +00003509</div>
Chris Lattner54611b42005-11-06 08:02:57 +00003510
Chris Lattner2f7c9632001-06-06 20:29:01 +00003511<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00003512<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
3513Instruction</a> </div>
Misha Brukman76307852003-11-08 01:05:38 +00003514<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +00003515<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +00003516<pre> &lt;result&gt; = load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br> &lt;result&gt; = volatile load &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;]<br></pre>
Chris Lattner095735d2002-05-06 03:03:22 +00003517<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +00003518<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +00003519<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00003520<p>The argument to the '<tt>load</tt>' instruction specifies the memory
John Criswell4c0cf7f2005-10-24 16:17:18 +00003521address from which to load. The pointer must point to a <a
Chris Lattner10ee9652004-06-03 22:57:15 +00003522 href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
John Criswell4c0cf7f2005-10-24 16:17:18 +00003523marked as <tt>volatile</tt>, then the optimizer is not allowed to modify
Chris Lattner48b383b02003-11-25 01:02:51 +00003524the number or order of execution of this <tt>load</tt> with other
3525volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
3526instructions. </p>
Chris Lattner2a1993f2008-01-06 21:04:43 +00003527<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +00003528The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +00003529(that is, the alignment of the memory address). A value of 0 or an
3530omitted "align" argument means that the operation has the preferential
3531alignment for the target. It is the responsibility of the code emitter
3532to ensure that the alignment information is correct. Overestimating
3533the alignment results in an undefined behavior. Underestimating the
3534alignment may produce less efficient code. An alignment of 1 is always
3535safe.
3536</p>
Chris Lattner095735d2002-05-06 03:03:22 +00003537<h5>Semantics:</h5>
Duncan Sandsb1656c12009-03-22 11:33:16 +00003538<p>The location of memory pointed to is loaded. If the value being loaded
3539is of scalar type then the number of bytes read does not exceed the minimum
3540number of bytes needed to hold all bits of the type. For example, loading an
3541<tt>i24</tt> reads at most three bytes. When loading a value of a type like
3542<tt>i20</tt> with a size that is not an integral number of bytes, the result
3543is undefined if the value was not originally written using a store of the
3544same type.</p>
Chris Lattner095735d2002-05-06 03:03:22 +00003545<h5>Examples:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003546<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Chris Lattner48b383b02003-11-25 01:02:51 +00003547 <a
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003548 href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
3549 %val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +00003550</pre>
Misha Brukman76307852003-11-08 01:05:38 +00003551</div>
Chris Lattner095735d2002-05-06 03:03:22 +00003552<!-- _______________________________________________________________________ -->
Chris Lattner48b383b02003-11-25 01:02:51 +00003553<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
3554Instruction</a> </div>
Reid Spencera89fb182006-11-09 21:18:01 +00003555<div class="doc_text">
Chris Lattner095735d2002-05-06 03:03:22 +00003556<h5>Syntax:</h5>
Christopher Lambbff50202007-04-21 08:16:25 +00003557<pre> store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
3558 volatile store &lt;ty&gt; &lt;value&gt;, &lt;ty&gt;* &lt;pointer&gt;[, align &lt;alignment&gt;] <i>; yields {void}</i>
Chris Lattner095735d2002-05-06 03:03:22 +00003559</pre>
Chris Lattner095735d2002-05-06 03:03:22 +00003560<h5>Overview:</h5>
Misha Brukman76307852003-11-08 01:05:38 +00003561<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Chris Lattner095735d2002-05-06 03:03:22 +00003562<h5>Arguments:</h5>
Chris Lattner48b383b02003-11-25 01:02:51 +00003563<p>There are two arguments to the '<tt>store</tt>' instruction: a value
Jeff Cohen5819f182007-04-22 01:17:39 +00003564to store and an address at which to store it. The type of the '<tt>&lt;pointer&gt;</tt>'
Chris Lattner1f17cce2008-04-02 00:38:26 +00003565operand must be a pointer to the <a href="#t_firstclass">first class</a> type
3566of the '<tt>&lt;value&gt;</tt>'
John Criswell4a3327e2005-05-13 22:25:59 +00003567operand. If the <tt>store</tt> is marked as <tt>volatile</tt>, then the
Chris Lattner48b383b02003-11-25 01:02:51 +00003568optimizer is not allowed to modify the number or order of execution of
3569this <tt>store</tt> with other volatile <tt>load</tt> and <tt><a
3570 href="#i_store">store</a></tt> instructions.</p>
Chris Lattner2a1993f2008-01-06 21:04:43 +00003571<p>
Chris Lattner1f17cce2008-04-02 00:38:26 +00003572The optional constant "align" argument specifies the alignment of the operation
Chris Lattner2a1993f2008-01-06 21:04:43 +00003573(that is, the alignment of the memory address). A value of 0 or an
3574omitted "align" argument means that the operation has the preferential
3575alignment for the target. It is the responsibility of the code emitter
3576to ensure that the alignment information is correct. Overestimating
3577the alignment results in an undefined behavior. Underestimating the
3578alignment may produce less efficient code. An alignment of 1 is always
3579safe.
3580</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00003581<h5>Semantics:</h5>
3582<p>The contents of memory are updated to contain '<tt>&lt;value&gt;</tt>'
Duncan Sandsb1656c12009-03-22 11:33:16 +00003583at the location specified by the '<tt>&lt;pointer&gt;</tt>' operand.
3584If '<tt>&lt;value&gt;</tt>' is of scalar type then the number of bytes
3585written does not exceed the minimum number of bytes needed to hold all
3586bits of the type. For example, storing an <tt>i24</tt> writes at most
3587three bytes. When writing a value of a type like <tt>i20</tt> with a
3588size that is not an integral number of bytes, it is unspecified what
3589happens to the extra bits that do not belong to the type, but they will
3590typically be overwritten.</p>
Chris Lattner095735d2002-05-06 03:03:22 +00003591<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003592<pre> %ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling8830ffe2007-10-22 05:10:05 +00003593 store i32 3, i32* %ptr <i>; yields {void}</i>
3594 %val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Chris Lattner095735d2002-05-06 03:03:22 +00003595</pre>
Reid Spencer443460a2006-11-09 21:15:49 +00003596</div>
3597
Chris Lattner095735d2002-05-06 03:03:22 +00003598<!-- _______________________________________________________________________ -->
Chris Lattner33fd7022004-04-05 01:30:49 +00003599<div class="doc_subsubsection">
3600 <a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
3601</div>
3602
Misha Brukman76307852003-11-08 01:05:38 +00003603<div class="doc_text">
Chris Lattner590645f2002-04-14 06:13:44 +00003604<h5>Syntax:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +00003605<pre>
Matthijs Kooijman0e268272008-10-13 13:44:15 +00003606 &lt;result&gt; = getelementptr &lt;pty&gt;* &lt;ptrval&gt;{, &lt;ty&gt; &lt;idx&gt;}*
Chris Lattner33fd7022004-04-05 01:30:49 +00003607</pre>
3608
Chris Lattner590645f2002-04-14 06:13:44 +00003609<h5>Overview:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +00003610
3611<p>
3612The '<tt>getelementptr</tt>' instruction is used to get the address of a
Matthijs Kooijman0e268272008-10-13 13:44:15 +00003613subelement of an aggregate data structure. It performs address calculation only
3614and does not access memory.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +00003615
Chris Lattner590645f2002-04-14 06:13:44 +00003616<h5>Arguments:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +00003617
Matthijs Kooijman0e268272008-10-13 13:44:15 +00003618<p>The first argument is always a pointer, and forms the basis of the
3619calculation. The remaining arguments are indices, that indicate which of the
3620elements of the aggregate object are indexed. The interpretation of each index
3621is dependent on the type being indexed into. The first index always indexes the
3622pointer value given as the first argument, the second index indexes a value of
3623the type pointed to (not necessarily the value directly pointed to, since the
3624first index can be non-zero), etc. The first type indexed into must be a pointer
3625value, subsequent types can be arrays, vectors and structs. Note that subsequent
3626types being indexed into can never be pointers, since that would require loading
3627the pointer before continuing calculation.</p>
3628
3629<p>The type of each index argument depends on the type it is indexing into.
3630When indexing into a (packed) structure, only <tt>i32</tt> integer
3631<b>constants</b> are allowed. When indexing into an array, pointer or vector,
3632only integers of 32 or 64 bits are allowed (also non-constants). 32-bit values
3633will be sign extended to 64-bits if required.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +00003634
Chris Lattner48b383b02003-11-25 01:02:51 +00003635<p>For example, let's consider a C code fragment and how it gets
3636compiled to LLVM:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +00003637
Bill Wendling3716c5d2007-05-29 09:04:49 +00003638<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +00003639<pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00003640struct RT {
3641 char A;
Chris Lattnera446f1b2007-05-29 15:43:56 +00003642 int B[10][20];
Bill Wendling3716c5d2007-05-29 09:04:49 +00003643 char C;
3644};
3645struct ST {
Chris Lattnera446f1b2007-05-29 15:43:56 +00003646 int X;
Bill Wendling3716c5d2007-05-29 09:04:49 +00003647 double Y;
3648 struct RT Z;
3649};
Chris Lattner33fd7022004-04-05 01:30:49 +00003650
Chris Lattnera446f1b2007-05-29 15:43:56 +00003651int *foo(struct ST *s) {
Bill Wendling3716c5d2007-05-29 09:04:49 +00003652 return &amp;s[1].Z.B[5][13];
3653}
Chris Lattner33fd7022004-04-05 01:30:49 +00003654</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00003655</div>
Chris Lattner33fd7022004-04-05 01:30:49 +00003656
Misha Brukman76307852003-11-08 01:05:38 +00003657<p>The LLVM code generated by the GCC frontend is:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +00003658
Bill Wendling3716c5d2007-05-29 09:04:49 +00003659<div class="doc_code">
Chris Lattner33fd7022004-04-05 01:30:49 +00003660<pre>
Chris Lattnerbc088212009-01-11 20:53:49 +00003661%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
3662%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Chris Lattner33fd7022004-04-05 01:30:49 +00003663
Bill Wendling3716c5d2007-05-29 09:04:49 +00003664define i32* %foo(%ST* %s) {
3665entry:
3666 %reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
3667 ret i32* %reg
3668}
Chris Lattner33fd7022004-04-05 01:30:49 +00003669</pre>
Bill Wendling3716c5d2007-05-29 09:04:49 +00003670</div>
Chris Lattner33fd7022004-04-05 01:30:49 +00003671
Chris Lattner590645f2002-04-14 06:13:44 +00003672<h5>Semantics:</h5>
Chris Lattner33fd7022004-04-05 01:30:49 +00003673
Misha Brukman76307852003-11-08 01:05:38 +00003674<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003675type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
Chris Lattner33fd7022004-04-05 01:30:49 +00003676}</tt>' type, a structure. The second index indexes into the third element of
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003677the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
3678i8 }</tt>' type, another structure. The third index indexes into the second
3679element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
Chris Lattner33fd7022004-04-05 01:30:49 +00003680array. The two dimensions of the array are subscripted into, yielding an
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003681'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a pointer
3682to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Chris Lattner33fd7022004-04-05 01:30:49 +00003683
Chris Lattner48b383b02003-11-25 01:02:51 +00003684<p>Note that it is perfectly legal to index partially through a
3685structure, returning a pointer to an inner element. Because of this,
3686the LLVM code for the given testcase is equivalent to:</p>
Chris Lattner33fd7022004-04-05 01:30:49 +00003687
3688<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003689 define i32* %foo(%ST* %s) {
3690 %t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
Jeff Cohen5819f182007-04-22 01:17:39 +00003691 %t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
3692 %t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003693 %t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
3694 %t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
3695 ret i32* %t5
Chris Lattner33fd7022004-04-05 01:30:49 +00003696 }
Chris Lattnera8292f32002-05-06 22:08:29 +00003697</pre>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +00003698
Chris Lattnerdd282822009-03-09 20:55:18 +00003699<p>Note that it is undefined to access an array out of bounds: array
3700and pointer indexes must always be within the defined bounds of the
3701array type when accessed with an instruction that dereferences the
3702pointer (e.g. a load or store instruction). The one exception for
3703this rule is zero length arrays. These arrays are defined to be
3704accessible as variable length arrays, which requires access beyond the
3705zero'th element.</p>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +00003706
Chris Lattner6ab66722006-08-15 00:45:58 +00003707<p>The getelementptr instruction is often confusing. For some more insight
3708into how it works, see <a href="GetElementPtr.html">the getelementptr
3709FAQ</a>.</p>
3710
Chris Lattner590645f2002-04-14 06:13:44 +00003711<h5>Example:</h5>
Chris Lattnerc0ad71e2005-06-24 17:22:57 +00003712
Chris Lattner33fd7022004-04-05 01:30:49 +00003713<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003714 <i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman0e268272008-10-13 13:44:15 +00003715 %aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
3716 <i>; yields i8*:vptr</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +00003717 %vptr = getelementptr {i32, &lt;2 x i8&gt;}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman0e268272008-10-13 13:44:15 +00003718 <i>; yields i8*:eptr</i>
3719 %eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Chris Lattner33fd7022004-04-05 01:30:49 +00003720</pre>
Chris Lattner33fd7022004-04-05 01:30:49 +00003721</div>
Reid Spencer443460a2006-11-09 21:15:49 +00003722
Chris Lattner2f7c9632001-06-06 20:29:01 +00003723<!-- ======================================================================= -->
Reid Spencer97c5fa42006-11-08 01:18:52 +00003724<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
Misha Brukman76307852003-11-08 01:05:38 +00003725</div>
Misha Brukman76307852003-11-08 01:05:38 +00003726<div class="doc_text">
Reid Spencer97c5fa42006-11-08 01:18:52 +00003727<p>The instructions in this category are the conversion instructions (casting)
3728which all take a single operand and a type. They perform various bit conversions
3729on the operand.</p>
Misha Brukman76307852003-11-08 01:05:38 +00003730</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00003731
Chris Lattnera8292f32002-05-06 22:08:29 +00003732<!-- _______________________________________________________________________ -->
Chris Lattnerb53c28d2004-03-12 05:50:16 +00003733<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003734 <a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
3735</div>
3736<div class="doc_text">
3737
3738<h5>Syntax:</h5>
3739<pre>
3740 &lt;result&gt; = trunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3741</pre>
3742
3743<h5>Overview:</h5>
3744<p>
3745The '<tt>trunc</tt>' instruction truncates its operand to the type <tt>ty2</tt>.
3746</p>
3747
3748<h5>Arguments:</h5>
3749<p>
3750The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
3751be an <a href="#t_integer">integer</a> type, and a type that specifies the size
Chris Lattnerc0f423a2007-01-15 01:54:13 +00003752and type of the result, which must be an <a href="#t_integer">integer</a>
Reid Spencer51b07252006-11-09 23:03:26 +00003753type. The bit size of <tt>value</tt> must be larger than the bit size of
3754<tt>ty2</tt>. Equal sized types are not allowed.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003755
3756<h5>Semantics:</h5>
3757<p>
3758The '<tt>trunc</tt>' instruction truncates the high order bits in <tt>value</tt>
Reid Spencer51b07252006-11-09 23:03:26 +00003759and converts the remaining bits to <tt>ty2</tt>. Since the source size must be
3760larger than the destination size, <tt>trunc</tt> cannot be a <i>no-op cast</i>.
3761It will always truncate bits.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003762
3763<h5>Example:</h5>
3764<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003765 %X = trunc i32 257 to i8 <i>; yields i8:1</i>
Reid Spencer36a15422007-01-12 03:35:51 +00003766 %Y = trunc i32 123 to i1 <i>; yields i1:true</i>
3767 %Y = trunc i32 122 to i1 <i>; yields i1:false</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003768</pre>
3769</div>
3770
3771<!-- _______________________________________________________________________ -->
3772<div class="doc_subsubsection">
3773 <a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
3774</div>
3775<div class="doc_text">
3776
3777<h5>Syntax:</h5>
3778<pre>
3779 &lt;result&gt; = zext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3780</pre>
3781
3782<h5>Overview:</h5>
3783<p>The '<tt>zext</tt>' instruction zero extends its operand to type
3784<tt>ty2</tt>.</p>
3785
3786
3787<h5>Arguments:</h5>
3788<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +00003789<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3790also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +00003791<tt>value</tt> must be smaller than the bit size of the destination type,
3792<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003793
3794<h5>Semantics:</h5>
3795<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Chris Lattnerc87f3df2007-05-24 19:13:27 +00003796bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003797
Reid Spencer07c9c682007-01-12 15:46:11 +00003798<p>When zero extending from i1, the result will always be either 0 or 1.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003799
3800<h5>Example:</h5>
3801<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003802 %X = zext i32 257 to i64 <i>; yields i64:257</i>
Reid Spencer36a15422007-01-12 03:35:51 +00003803 %Y = zext i1 true to i32 <i>; yields i32:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003804</pre>
3805</div>
3806
3807<!-- _______________________________________________________________________ -->
3808<div class="doc_subsubsection">
3809 <a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
3810</div>
3811<div class="doc_text">
3812
3813<h5>Syntax:</h5>
3814<pre>
3815 &lt;result&gt; = sext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3816</pre>
3817
3818<h5>Overview:</h5>
3819<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
3820
3821<h5>Arguments:</h5>
3822<p>
3823The '<tt>sext</tt>' instruction takes a value to cast, which must be of
Chris Lattnerc0f423a2007-01-15 01:54:13 +00003824<a href="#t_integer">integer</a> type, and a type to cast it to, which must
3825also be of <a href="#t_integer">integer</a> type. The bit size of the
Reid Spencer51b07252006-11-09 23:03:26 +00003826<tt>value</tt> must be smaller than the bit size of the destination type,
3827<tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003828
3829<h5>Semantics:</h5>
3830<p>
3831The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
3832bit (highest order bit) of the <tt>value</tt> until it reaches the bit size of
Chris Lattnerc87f3df2007-05-24 19:13:27 +00003833the type <tt>ty2</tt>.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003834
Reid Spencer36a15422007-01-12 03:35:51 +00003835<p>When sign extending from i1, the extension always results in -1 or 0.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003836
3837<h5>Example:</h5>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003838<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003839 %X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
Reid Spencer36a15422007-01-12 03:35:51 +00003840 %Y = sext i1 true to i32 <i>; yields i32:-1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003841</pre>
3842</div>
3843
3844<!-- _______________________________________________________________________ -->
3845<div class="doc_subsubsection">
Reid Spencer2e2740d2006-11-09 21:48:10 +00003846 <a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
3847</div>
3848
3849<div class="doc_text">
3850
3851<h5>Syntax:</h5>
3852
3853<pre>
3854 &lt;result&gt; = fptrunc &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3855</pre>
3856
3857<h5>Overview:</h5>
3858<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
3859<tt>ty2</tt>.</p>
3860
3861
3862<h5>Arguments:</h5>
3863<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
3864 point</a> value to cast and a <a href="#t_floating">floating point</a> type to
3865cast it to. The size of <tt>value</tt> must be larger than the size of
3866<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
3867<i>no-op cast</i>.</p>
3868
3869<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00003870<p> The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
3871<a href="#t_floating">floating point</a> type to a smaller
3872<a href="#t_floating">floating point</a> type. If the value cannot fit within
3873the destination type, <tt>ty2</tt>, then the results are undefined.</p>
Reid Spencer2e2740d2006-11-09 21:48:10 +00003874
3875<h5>Example:</h5>
3876<pre>
3877 %X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
3878 %Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
3879</pre>
3880</div>
3881
3882<!-- _______________________________________________________________________ -->
3883<div class="doc_subsubsection">
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003884 <a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
3885</div>
3886<div class="doc_text">
3887
3888<h5>Syntax:</h5>
3889<pre>
3890 &lt;result&gt; = fpext &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
3891</pre>
3892
3893<h5>Overview:</h5>
3894<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
3895floating point value.</p>
3896
3897<h5>Arguments:</h5>
3898<p>The '<tt>fpext</tt>' instruction takes a
3899<a href="#t_floating">floating point</a> <tt>value</tt> to cast,
Reid Spencer51b07252006-11-09 23:03:26 +00003900and a <a href="#t_floating">floating point</a> type to cast it to. The source
3901type must be smaller than the destination type.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003902
3903<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00003904<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Duncan Sands16f122e2007-03-30 12:22:09 +00003905<a href="#t_floating">floating point</a> type to a larger
3906<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
Reid Spencer51b07252006-11-09 23:03:26 +00003907used to make a <i>no-op cast</i> because it always changes bits. Use
Reid Spencer5b950642006-11-11 23:08:07 +00003908<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003909
3910<h5>Example:</h5>
3911<pre>
3912 %X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
3913 %Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
3914</pre>
3915</div>
3916
3917<!-- _______________________________________________________________________ -->
3918<div class="doc_subsubsection">
Reid Spencer2eadb532007-01-21 00:29:26 +00003919 <a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003920</div>
3921<div class="doc_text">
3922
3923<h5>Syntax:</h5>
3924<pre>
Reid Spencer753163d2007-07-31 14:40:14 +00003925 &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 +00003926</pre>
3927
3928<h5>Overview:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +00003929<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003930unsigned integer equivalent of type <tt>ty2</tt>.
3931</p>
3932
3933<h5>Arguments:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +00003934<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
Nate Begemand4d45c22007-11-17 03:58:34 +00003935scalar or vector <a href="#t_floating">floating point</a> value, and a type
3936to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3937type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3938vector integer type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003939
3940<h5>Semantics:</h5>
Reid Spencer753163d2007-07-31 14:40:14 +00003941<p> The '<tt>fptoui</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003942<a href="#t_floating">floating point</a> operand into the nearest (rounding
3943towards zero) unsigned integer value. If the value cannot fit in <tt>ty2</tt>,
3944the results are undefined.</p>
3945
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003946<h5>Example:</h5>
3947<pre>
Reid Spencer753163d2007-07-31 14:40:14 +00003948 %X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +00003949 %Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer753163d2007-07-31 14:40:14 +00003950 %X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003951</pre>
3952</div>
3953
3954<!-- _______________________________________________________________________ -->
3955<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +00003956 <a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003957</div>
3958<div class="doc_text">
3959
3960<h5>Syntax:</h5>
3961<pre>
Reid Spencer51b07252006-11-09 23:03:26 +00003962 &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 +00003963</pre>
3964
3965<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00003966<p>The '<tt>fptosi</tt>' instruction converts
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003967<a href="#t_floating">floating point</a> <tt>value</tt> to type <tt>ty2</tt>.
Chris Lattnerb53c28d2004-03-12 05:50:16 +00003968</p>
3969
Chris Lattnera8292f32002-05-06 22:08:29 +00003970<h5>Arguments:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00003971<p> The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
Nate Begemand4d45c22007-11-17 03:58:34 +00003972scalar or vector <a href="#t_floating">floating point</a> value, and a type
3973to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
3974type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
3975vector integer type with the same number of elements as <tt>ty</tt></p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00003976
Chris Lattnera8292f32002-05-06 22:08:29 +00003977<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00003978<p>The '<tt>fptosi</tt>' instruction converts its
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003979<a href="#t_floating">floating point</a> operand into the nearest (rounding
3980towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
3981the results are undefined.</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00003982
Chris Lattner70de6632001-07-09 00:26:23 +00003983<h5>Example:</h5>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00003984<pre>
Reid Spencer36a15422007-01-12 03:35:51 +00003985 %X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner5b95a172007-09-22 03:17:52 +00003986 %Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00003987 %X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003988</pre>
3989</div>
3990
3991<!-- _______________________________________________________________________ -->
3992<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +00003993 <a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00003994</div>
3995<div class="doc_text">
3996
3997<h5>Syntax:</h5>
3998<pre>
Reid Spencer51b07252006-11-09 23:03:26 +00003999 &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 +00004000</pre>
4001
4002<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00004003<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004004integer and converts that value to the <tt>ty2</tt> type.</p>
4005
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004006<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +00004007<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
4008scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4009to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4010type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4011floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004012
4013<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00004014<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004015integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +00004016the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004017
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004018<h5>Example:</h5>
4019<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00004020 %X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +00004021 %Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004022</pre>
4023</div>
4024
4025<!-- _______________________________________________________________________ -->
4026<div class="doc_subsubsection">
Reid Spencer51b07252006-11-09 23:03:26 +00004027 <a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004028</div>
4029<div class="doc_text">
4030
4031<h5>Syntax:</h5>
4032<pre>
Reid Spencer51b07252006-11-09 23:03:26 +00004033 &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 +00004034</pre>
4035
4036<h5>Overview:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00004037<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004038integer and converts that value to the <tt>ty2</tt> type.</p>
4039
4040<h5>Arguments:</h5>
Nate Begemand4d45c22007-11-17 03:58:34 +00004041<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
4042scalar or vector <a href="#t_integer">integer</a> value, and a type to cast it
4043to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
4044type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
4045floating point type with the same number of elements as <tt>ty</tt></p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004046
4047<h5>Semantics:</h5>
Reid Spencer51b07252006-11-09 23:03:26 +00004048<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004049integer quantity and converts it to the corresponding floating point value. If
Jeff Cohenbeccb742007-04-22 14:56:37 +00004050the value cannot fit in the floating point value, the results are undefined.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004051
4052<h5>Example:</h5>
4053<pre>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00004054 %X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +00004055 %Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004056</pre>
4057</div>
4058
4059<!-- _______________________________________________________________________ -->
4060<div class="doc_subsubsection">
Reid Spencerb7344ff2006-11-11 21:00:47 +00004061 <a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
4062</div>
4063<div class="doc_text">
4064
4065<h5>Syntax:</h5>
4066<pre>
4067 &lt;result&gt; = ptrtoint &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4068</pre>
4069
4070<h5>Overview:</h5>
4071<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
4072the integer type <tt>ty2</tt>.</p>
4073
4074<h5>Arguments:</h5>
4075<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
Duncan Sands16f122e2007-03-30 12:22:09 +00004076must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
Dan Gohmanef9462f2008-10-14 16:51:45 +00004077<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +00004078
4079<h5>Semantics:</h5>
4080<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
4081<tt>ty2</tt> by interpreting the pointer value as an integer and either
4082truncating or zero extending that value to the size of the integer type. If
4083<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
4084<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
Jeff Cohen222a8a42007-04-29 01:07:00 +00004085are the same size, then nothing is done (<i>no-op cast</i>) other than a type
4086change.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +00004087
4088<h5>Example:</h5>
4089<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +00004090 %X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
4091 %Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +00004092</pre>
4093</div>
4094
4095<!-- _______________________________________________________________________ -->
4096<div class="doc_subsubsection">
4097 <a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
4098</div>
4099<div class="doc_text">
4100
4101<h5>Syntax:</h5>
4102<pre>
4103 &lt;result&gt; = inttoptr &lt;ty&gt; &lt;value&gt; to &lt;ty2&gt; <i>; yields ty2</i>
4104</pre>
4105
4106<h5>Overview:</h5>
4107<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to
4108a pointer type, <tt>ty2</tt>.</p>
4109
4110<h5>Arguments:</h5>
Duncan Sands16f122e2007-03-30 12:22:09 +00004111<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Reid Spencerb7344ff2006-11-11 21:00:47 +00004112value to cast, and a type to cast it to, which must be a
Dan Gohmanef9462f2008-10-14 16:51:45 +00004113<a href="#t_pointer">pointer</a> type.</p>
Reid Spencerb7344ff2006-11-11 21:00:47 +00004114
4115<h5>Semantics:</h5>
4116<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
4117<tt>ty2</tt> by applying either a zero extension or a truncation depending on
4118the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
4119size of a pointer then a truncation is done. If <tt>value</tt> is smaller than
4120the size of a pointer then a zero extension is done. If they are the same size,
4121nothing is done (<i>no-op cast</i>).</p>
4122
4123<h5>Example:</h5>
4124<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +00004125 %X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
4126 %X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
4127 %Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
Reid Spencerb7344ff2006-11-11 21:00:47 +00004128</pre>
4129</div>
4130
4131<!-- _______________________________________________________________________ -->
4132<div class="doc_subsubsection">
Reid Spencer5b950642006-11-11 23:08:07 +00004133 <a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004134</div>
4135<div class="doc_text">
4136
4137<h5>Syntax:</h5>
4138<pre>
Reid Spencer5b950642006-11-11 23:08:07 +00004139 &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 +00004140</pre>
4141
4142<h5>Overview:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004143
Reid Spencer5b950642006-11-11 23:08:07 +00004144<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004145<tt>ty2</tt> without changing any bits.</p>
4146
4147<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004148
Reid Spencer5b950642006-11-11 23:08:07 +00004149<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be
Dan Gohmanc05dca92008-09-08 16:45:59 +00004150a non-aggregate first class value, and a type to cast it to, which must also be
4151a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes of
4152<tt>value</tt>
Reid Spencere3db84c2007-01-09 20:08:58 +00004153and the destination type, <tt>ty2</tt>, must be identical. If the source
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004154type is a pointer, the destination type must also be a pointer. This
4155instruction supports bitwise conversion of vectors to integers and to vectors
4156of other types (as long as they have the same size).</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004157
4158<h5>Semantics:</h5>
Reid Spencer5b950642006-11-11 23:08:07 +00004159<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Reid Spencerb7344ff2006-11-11 21:00:47 +00004160<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
4161this conversion. The conversion is done as if the <tt>value</tt> had been
4162stored to memory and read back as type <tt>ty2</tt>. Pointer types may only be
4163converted to other pointer types with this instruction. To convert pointers to
4164other types, use the <a href="#i_inttoptr">inttoptr</a> or
4165<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Reid Spencer59b6b7d2006-11-08 01:11:31 +00004166
4167<h5>Example:</h5>
4168<pre>
Jeff Cohen222a8a42007-04-29 01:07:00 +00004169 %X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00004170 %Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohmanef9462f2008-10-14 16:51:45 +00004171 %Z = bitcast &lt;2 x int&gt; %V to i64; <i>; yields i64: %V</i>
Chris Lattner70de6632001-07-09 00:26:23 +00004172</pre>
Misha Brukman76307852003-11-08 01:05:38 +00004173</div>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004174
Reid Spencer97c5fa42006-11-08 01:18:52 +00004175<!-- ======================================================================= -->
4176<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
4177<div class="doc_text">
4178<p>The instructions in this category are the "miscellaneous"
4179instructions, which defy better classification.</p>
4180</div>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004181
4182<!-- _______________________________________________________________________ -->
4183<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
4184</div>
4185<div class="doc_text">
4186<h5>Syntax:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +00004187<pre> &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 +00004188</pre>
4189<h5>Overview:</h5>
Dan Gohmanc579d972008-09-09 01:02:47 +00004190<p>The '<tt>icmp</tt>' instruction returns a boolean value or
4191a vector of boolean values based on comparison
4192of its two integer, integer vector, or pointer operands.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004193<h5>Arguments:</h5>
4194<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +00004195the condition code indicating the kind of comparison to perform. It is not
4196a value, just a keyword. The possible condition code are:
Dan Gohmanef9462f2008-10-14 16:51:45 +00004197</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004198<ol>
4199 <li><tt>eq</tt>: equal</li>
4200 <li><tt>ne</tt>: not equal </li>
4201 <li><tt>ugt</tt>: unsigned greater than</li>
4202 <li><tt>uge</tt>: unsigned greater or equal</li>
4203 <li><tt>ult</tt>: unsigned less than</li>
4204 <li><tt>ule</tt>: unsigned less or equal</li>
4205 <li><tt>sgt</tt>: signed greater than</li>
4206 <li><tt>sge</tt>: signed greater or equal</li>
4207 <li><tt>slt</tt>: signed less than</li>
4208 <li><tt>sle</tt>: signed less or equal</li>
4209</ol>
Chris Lattnerc0f423a2007-01-15 01:54:13 +00004210<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Dan Gohmanc579d972008-09-09 01:02:47 +00004211<a href="#t_pointer">pointer</a>
4212or integer <a href="#t_vector">vector</a> typed.
4213They must also be identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004214<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00004215<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to
Reid Spencerc828a0e2006-11-18 21:50:54 +00004216the condition code given as <tt>cond</tt>. The comparison performed always
Dan Gohmanc579d972008-09-09 01:02:47 +00004217yields either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt> result, as follows:
Dan Gohmanef9462f2008-10-14 16:51:45 +00004218</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004219<ol>
4220 <li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
4221 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.
4222 </li>
4223 <li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Dan Gohmanef9462f2008-10-14 16:51:45 +00004224 <tt>false</tt> otherwise. No sign interpretation is necessary or performed.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004225 <li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004226 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004227 <li><tt>uge</tt>: interprets the operands as unsigned values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004228 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004229 <li><tt>ult</tt>: interprets the operands as unsigned values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004230 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004231 <li><tt>ule</tt>: interprets the operands as unsigned values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004232 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004233 <li><tt>sgt</tt>: interprets the operands as signed values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004234 <tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004235 <li><tt>sge</tt>: interprets the operands as signed values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004236 <tt>true</tt> if <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004237 <li><tt>slt</tt>: interprets the operands as signed values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004238 <tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004239 <li><tt>sle</tt>: interprets the operands as signed values and yields
Gabor Greif0f75ad02008-08-07 21:46:00 +00004240 <tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004241</ol>
4242<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Jeff Cohen222a8a42007-04-29 01:07:00 +00004243values are compared as if they were integers.</p>
Dan Gohmanc579d972008-09-09 01:02:47 +00004244<p>If the operands are integer vectors, then they are compared
4245element by element. The result is an <tt>i1</tt> vector with
4246the same number of elements as the values being compared.
4247Otherwise, the result is an <tt>i1</tt>.
4248</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004249
4250<h5>Example:</h5>
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00004251<pre> &lt;result&gt; = icmp eq i32 4, 5 <i>; yields: result=false</i>
4252 &lt;result&gt; = icmp ne float* %X, %X <i>; yields: result=false</i>
4253 &lt;result&gt; = icmp ult i16 4, 5 <i>; yields: result=true</i>
4254 &lt;result&gt; = icmp sgt i16 4, 5 <i>; yields: result=false</i>
4255 &lt;result&gt; = icmp ule i16 -4, 5 <i>; yields: result=false</i>
4256 &lt;result&gt; = icmp sge i16 4, 5 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004257</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +00004258
4259<p>Note that the code generator does not yet support vector types with
4260 the <tt>icmp</tt> instruction.</p>
4261
Reid Spencerc828a0e2006-11-18 21:50:54 +00004262</div>
4263
4264<!-- _______________________________________________________________________ -->
4265<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
4266</div>
4267<div class="doc_text">
4268<h5>Syntax:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +00004269<pre> &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 +00004270</pre>
4271<h5>Overview:</h5>
Dan Gohmanc579d972008-09-09 01:02:47 +00004272<p>The '<tt>fcmp</tt>' instruction returns a boolean value
4273or vector of boolean values based on comparison
Dan Gohmanef9462f2008-10-14 16:51:45 +00004274of its operands.</p>
Dan Gohmanc579d972008-09-09 01:02:47 +00004275<p>
4276If the operands are floating point scalars, then the result
4277type is a boolean (<a href="#t_primitive"><tt>i1</tt></a>).
4278</p>
4279<p>If the operands are floating point vectors, then the result type
4280is a vector of boolean with the same number of elements as the
4281operands being compared.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004282<h5>Arguments:</h5>
4283<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Jeff Cohen222a8a42007-04-29 01:07:00 +00004284the condition code indicating the kind of comparison to perform. It is not
Dan Gohmanef9462f2008-10-14 16:51:45 +00004285a value, just a keyword. The possible condition code are:</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004286<ol>
Reid Spencerf69acf32006-11-19 03:00:14 +00004287 <li><tt>false</tt>: no comparison, always returns false</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004288 <li><tt>oeq</tt>: ordered and equal</li>
4289 <li><tt>ogt</tt>: ordered and greater than </li>
4290 <li><tt>oge</tt>: ordered and greater than or equal</li>
4291 <li><tt>olt</tt>: ordered and less than </li>
4292 <li><tt>ole</tt>: ordered and less than or equal</li>
4293 <li><tt>one</tt>: ordered and not equal</li>
4294 <li><tt>ord</tt>: ordered (no nans)</li>
4295 <li><tt>ueq</tt>: unordered or equal</li>
4296 <li><tt>ugt</tt>: unordered or greater than </li>
4297 <li><tt>uge</tt>: unordered or greater than or equal</li>
4298 <li><tt>ult</tt>: unordered or less than </li>
4299 <li><tt>ule</tt>: unordered or less than or equal</li>
4300 <li><tt>une</tt>: unordered or not equal</li>
4301 <li><tt>uno</tt>: unordered (either nans)</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004302 <li><tt>true</tt>: no comparison, always returns true</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004303</ol>
Jeff Cohen222a8a42007-04-29 01:07:00 +00004304<p><i>Ordered</i> means that neither operand is a QNAN while
Reid Spencer02e0d1d2006-12-06 07:08:07 +00004305<i>unordered</i> means that either operand may be a QNAN.</p>
Dan Gohmanc579d972008-09-09 01:02:47 +00004306<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be
4307either a <a href="#t_floating">floating point</a> type
4308or a <a href="#t_vector">vector</a> of floating point type.
4309They must have identical types.</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004310<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00004311<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Dan Gohmanc579d972008-09-09 01:02:47 +00004312according to the condition code given as <tt>cond</tt>.
4313If the operands are vectors, then the vectors are compared
4314element by element.
4315Each comparison performed
Dan Gohmanef9462f2008-10-14 16:51:45 +00004316always yields an <a href="#t_primitive">i1</a> result, as follows:</p>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004317<ol>
4318 <li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004319 <li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif0f75ad02008-08-07 21:46:00 +00004320 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004321 <li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif0f75ad02008-08-07 21:46:00 +00004322 <tt>op1</tt> is greather than <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004323 <li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif0f75ad02008-08-07 21:46:00 +00004324 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004325 <li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif0f75ad02008-08-07 21:46:00 +00004326 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004327 <li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif0f75ad02008-08-07 21:46:00 +00004328 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004329 <li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Gabor Greif0f75ad02008-08-07 21:46:00 +00004330 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004331 <li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
4332 <li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif0f75ad02008-08-07 21:46:00 +00004333 <tt>op1</tt> is equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004334 <li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif0f75ad02008-08-07 21:46:00 +00004335 <tt>op1</tt> is greater than <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004336 <li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif0f75ad02008-08-07 21:46:00 +00004337 <tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004338 <li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif0f75ad02008-08-07 21:46:00 +00004339 <tt>op1</tt> is less than <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004340 <li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif0f75ad02008-08-07 21:46:00 +00004341 <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004342 <li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Gabor Greif0f75ad02008-08-07 21:46:00 +00004343 <tt>op1</tt> is not equal to <tt>op2</tt>.</li>
Reid Spencerf69acf32006-11-19 03:00:14 +00004344 <li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004345 <li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
4346</ol>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004347
4348<h5>Example:</h5>
4349<pre> &lt;result&gt; = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohmanc579d972008-09-09 01:02:47 +00004350 &lt;result&gt; = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
4351 &lt;result&gt; = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
4352 &lt;result&gt; = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Reid Spencerc828a0e2006-11-18 21:50:54 +00004353</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +00004354
4355<p>Note that the code generator does not yet support vector types with
4356 the <tt>fcmp</tt> instruction.</p>
4357
Reid Spencerc828a0e2006-11-18 21:50:54 +00004358</div>
4359
Reid Spencer97c5fa42006-11-08 01:18:52 +00004360<!-- _______________________________________________________________________ -->
Nate Begemand2195702008-05-12 19:01:56 +00004361<div class="doc_subsubsection">
4362 <a name="i_vicmp">'<tt>vicmp</tt>' Instruction</a>
4363</div>
4364<div class="doc_text">
4365<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00004366<pre> &lt;result&gt; = vicmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt; <i>; yields {ty}:result</i>
Nate Begemand2195702008-05-12 19:01:56 +00004367</pre>
4368<h5>Overview:</h5>
4369<p>The '<tt>vicmp</tt>' instruction returns an integer vector value based on
4370element-wise comparison of its two integer vector operands.</p>
4371<h5>Arguments:</h5>
4372<p>The '<tt>vicmp</tt>' instruction takes three operands. The first operand is
4373the condition code indicating the kind of comparison to perform. It is not
Dan Gohmanef9462f2008-10-14 16:51:45 +00004374a value, just a keyword. The possible condition code are:</p>
Nate Begemand2195702008-05-12 19:01:56 +00004375<ol>
4376 <li><tt>eq</tt>: equal</li>
4377 <li><tt>ne</tt>: not equal </li>
4378 <li><tt>ugt</tt>: unsigned greater than</li>
4379 <li><tt>uge</tt>: unsigned greater or equal</li>
4380 <li><tt>ult</tt>: unsigned less than</li>
4381 <li><tt>ule</tt>: unsigned less or equal</li>
4382 <li><tt>sgt</tt>: signed greater than</li>
4383 <li><tt>sge</tt>: signed greater or equal</li>
4384 <li><tt>slt</tt>: signed less than</li>
4385 <li><tt>sle</tt>: signed less or equal</li>
4386</ol>
Dan Gohmanc579d972008-09-09 01:02:47 +00004387<p>The remaining two arguments must be <a href="#t_vector">vector</a> or
Nate Begemand2195702008-05-12 19:01:56 +00004388<a href="#t_integer">integer</a> typed. They must also be identical types.</p>
4389<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00004390<p>The '<tt>vicmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begemand2195702008-05-12 19:01:56 +00004391according to the condition code given as <tt>cond</tt>. The comparison yields a
4392<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, of
4393identical type as the values being compared. The most significant bit in each
4394element is 1 if the element-wise comparison evaluates to true, and is 0
4395otherwise. All other bits of the result are undefined. The condition codes
4396are evaluated identically to the <a href="#i_icmp">'<tt>icmp</tt>'
Dan Gohmanef9462f2008-10-14 16:51:45 +00004397instruction</a>.</p>
Nate Begemand2195702008-05-12 19:01:56 +00004398
4399<h5>Example:</h5>
4400<pre>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004401 &lt;result&gt; = vicmp eq &lt;2 x i32&gt; &lt; i32 4, i32 0&gt;, &lt; i32 5, i32 0&gt; <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4402 &lt;result&gt; = vicmp ult &lt;2 x i8 &gt; &lt; i8 1, i8 2&gt;, &lt; i8 2, i8 2 &gt; <i>; yields: result=&lt;2 x i8&gt; &lt; i8 -1, i8 0 &gt;</i>
Nate Begemand2195702008-05-12 19:01:56 +00004403</pre>
4404</div>
4405
4406<!-- _______________________________________________________________________ -->
4407<div class="doc_subsubsection">
4408 <a name="i_vfcmp">'<tt>vfcmp</tt>' Instruction</a>
4409</div>
4410<div class="doc_text">
4411<h5>Syntax:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00004412<pre> &lt;result&gt; = vfcmp &lt;cond&gt; &lt;ty&gt; &lt;op1&gt;, &lt;op2&gt;</pre>
Nate Begemand2195702008-05-12 19:01:56 +00004413<h5>Overview:</h5>
4414<p>The '<tt>vfcmp</tt>' instruction returns an integer vector value based on
4415element-wise comparison of its two floating point vector operands. The output
4416elements have the same width as the input elements.</p>
4417<h5>Arguments:</h5>
4418<p>The '<tt>vfcmp</tt>' instruction takes three operands. The first operand is
4419the condition code indicating the kind of comparison to perform. It is not
Dan Gohmanef9462f2008-10-14 16:51:45 +00004420a value, just a keyword. The possible condition code are:</p>
Nate Begemand2195702008-05-12 19:01:56 +00004421<ol>
4422 <li><tt>false</tt>: no comparison, always returns false</li>
4423 <li><tt>oeq</tt>: ordered and equal</li>
4424 <li><tt>ogt</tt>: ordered and greater than </li>
4425 <li><tt>oge</tt>: ordered and greater than or equal</li>
4426 <li><tt>olt</tt>: ordered and less than </li>
4427 <li><tt>ole</tt>: ordered and less than or equal</li>
4428 <li><tt>one</tt>: ordered and not equal</li>
4429 <li><tt>ord</tt>: ordered (no nans)</li>
4430 <li><tt>ueq</tt>: unordered or equal</li>
4431 <li><tt>ugt</tt>: unordered or greater than </li>
4432 <li><tt>uge</tt>: unordered or greater than or equal</li>
4433 <li><tt>ult</tt>: unordered or less than </li>
4434 <li><tt>ule</tt>: unordered or less than or equal</li>
4435 <li><tt>une</tt>: unordered or not equal</li>
4436 <li><tt>uno</tt>: unordered (either nans)</li>
4437 <li><tt>true</tt>: no comparison, always returns true</li>
4438</ol>
4439<p>The remaining two arguments must be <a href="#t_vector">vector</a> of
4440<a href="#t_floating">floating point</a> typed. They must also be identical
4441types.</p>
4442<h5>Semantics:</h5>
Gabor Greif0f75ad02008-08-07 21:46:00 +00004443<p>The '<tt>vfcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Nate Begemand2195702008-05-12 19:01:56 +00004444according to the condition code given as <tt>cond</tt>. The comparison yields a
4445<a href="#t_vector">vector</a> of <a href="#t_integer">integer</a> result, with
4446an identical number of elements as the values being compared, and each element
4447having identical with to the width of the floating point elements. The most
4448significant bit in each element is 1 if the element-wise comparison evaluates to
4449true, and is 0 otherwise. All other bits of the result are undefined. The
4450condition codes are evaluated identically to the
Dan Gohmanef9462f2008-10-14 16:51:45 +00004451<a href="#i_fcmp">'<tt>fcmp</tt>' instruction</a>.</p>
Nate Begemand2195702008-05-12 19:01:56 +00004452
4453<h5>Example:</h5>
4454<pre>
Chris Lattner0ae02092008-10-13 16:55:18 +00004455 <i>; yields: result=&lt;2 x i32&gt; &lt; i32 0, i32 -1 &gt;</i>
4456 &lt;result&gt; = vfcmp oeq &lt;2 x float&gt; &lt; float 4, float 0 &gt;, &lt; float 5, float 0 &gt;
4457
4458 <i>; yields: result=&lt;2 x i64&gt; &lt; i64 -1, i64 0 &gt;</i>
4459 &lt;result&gt; = vfcmp ult &lt;2 x double&gt; &lt; double 1, double 2 &gt;, &lt; double 2, double 2&gt;
Nate Begemand2195702008-05-12 19:01:56 +00004460</pre>
4461</div>
4462
4463<!-- _______________________________________________________________________ -->
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004464<div class="doc_subsubsection">
4465 <a name="i_phi">'<tt>phi</tt>' Instruction</a>
4466</div>
4467
Reid Spencer97c5fa42006-11-08 01:18:52 +00004468<div class="doc_text">
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004469
Reid Spencer97c5fa42006-11-08 01:18:52 +00004470<h5>Syntax:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004471
Reid Spencer97c5fa42006-11-08 01:18:52 +00004472<pre> &lt;result&gt; = phi &lt;ty&gt; [ &lt;val0&gt;, &lt;label0&gt;], ...<br></pre>
4473<h5>Overview:</h5>
4474<p>The '<tt>phi</tt>' instruction is used to implement the &#966; node in
4475the SSA graph representing the function.</p>
4476<h5>Arguments:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004477
Jeff Cohen222a8a42007-04-29 01:07:00 +00004478<p>The type of the incoming values is specified with the first type
Reid Spencer97c5fa42006-11-08 01:18:52 +00004479field. After this, the '<tt>phi</tt>' instruction takes a list of pairs
4480as arguments, with one pair for each predecessor basic block of the
4481current block. Only values of <a href="#t_firstclass">first class</a>
4482type may be used as the value arguments to the PHI node. Only labels
4483may be used as the label arguments.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004484
Reid Spencer97c5fa42006-11-08 01:18:52 +00004485<p>There must be no non-phi instructions between the start of a basic
4486block and the PHI instructions: i.e. PHI instructions must be first in
4487a basic block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004488
Reid Spencer97c5fa42006-11-08 01:18:52 +00004489<h5>Semantics:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004490
Jeff Cohen222a8a42007-04-29 01:07:00 +00004491<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
4492specified by the pair corresponding to the predecessor basic block that executed
4493just prior to the current block.</p>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004494
Reid Spencer97c5fa42006-11-08 01:18:52 +00004495<h5>Example:</h5>
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004496<pre>
4497Loop: ; Infinite loop that counts from 0 on up...
4498 %indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
4499 %nextindvar = add i32 %indvar, 1
4500 br label %Loop
4501</pre>
Reid Spencer97c5fa42006-11-08 01:18:52 +00004502</div>
4503
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004504<!-- _______________________________________________________________________ -->
4505<div class="doc_subsubsection">
4506 <a name="i_select">'<tt>select</tt>' Instruction</a>
4507</div>
4508
4509<div class="doc_text">
4510
4511<h5>Syntax:</h5>
4512
4513<pre>
Dan Gohmanc579d972008-09-09 01:02:47 +00004514 &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>
4515
Dan Gohmanef9462f2008-10-14 16:51:45 +00004516 <i>selty</i> is either i1 or {&lt;N x i1&gt;}
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004517</pre>
4518
4519<h5>Overview:</h5>
4520
4521<p>
4522The '<tt>select</tt>' instruction is used to choose one value based on a
4523condition, without branching.
4524</p>
4525
4526
4527<h5>Arguments:</h5>
4528
4529<p>
Dan Gohmanc579d972008-09-09 01:02:47 +00004530The '<tt>select</tt>' instruction requires an 'i1' value or
4531a vector of 'i1' values indicating the
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004532condition, and two values of the same <a href="#t_firstclass">first class</a>
Dan Gohmanc579d972008-09-09 01:02:47 +00004533type. If the val1/val2 are vectors and
4534the condition is a scalar, then entire vectors are selected, not
Chris Lattnerb54c30f2008-05-20 20:48:21 +00004535individual elements.
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004536</p>
4537
4538<h5>Semantics:</h5>
4539
4540<p>
Dan Gohmanc579d972008-09-09 01:02:47 +00004541If the condition is an i1 and it evaluates to 1, the instruction returns the first
John Criswell88190562005-05-16 16:17:45 +00004542value argument; otherwise, it returns the second value argument.
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004543</p>
Dan Gohmanc579d972008-09-09 01:02:47 +00004544<p>
4545If the condition is a vector of i1, then the value arguments must
4546be vectors of the same size, and the selection is done element
4547by element.
4548</p>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004549
4550<h5>Example:</h5>
4551
4552<pre>
Reid Spencer36a15422007-01-12 03:35:51 +00004553 %X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004554</pre>
Dan Gohmana5127ab2009-01-22 01:39:38 +00004555
4556<p>Note that the code generator does not yet support conditions
4557 with vector type.</p>
4558
Chris Lattnerb53c28d2004-03-12 05:50:16 +00004559</div>
4560
Robert Bocchinof72fdfe2006-01-15 20:48:27 +00004561
4562<!-- _______________________________________________________________________ -->
4563<div class="doc_subsubsection">
Chris Lattnere23c1392005-05-06 05:47:36 +00004564 <a name="i_call">'<tt>call</tt>' Instruction</a>
4565</div>
4566
Misha Brukman76307852003-11-08 01:05:38 +00004567<div class="doc_text">
Chris Lattnere23c1392005-05-06 05:47:36 +00004568
Chris Lattner2f7c9632001-06-06 20:29:01 +00004569<h5>Syntax:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +00004570<pre>
Devang Patel02256232008-10-07 17:48:33 +00004571 &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 +00004572</pre>
4573
Chris Lattner2f7c9632001-06-06 20:29:01 +00004574<h5>Overview:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +00004575
Misha Brukman76307852003-11-08 01:05:38 +00004576<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +00004577
Chris Lattner2f7c9632001-06-06 20:29:01 +00004578<h5>Arguments:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +00004579
Misha Brukman76307852003-11-08 01:05:38 +00004580<p>This instruction requires several arguments:</p>
Chris Lattnere23c1392005-05-06 05:47:36 +00004581
Chris Lattnera8292f32002-05-06 22:08:29 +00004582<ol>
Chris Lattner48b383b02003-11-25 01:02:51 +00004583 <li>
Chris Lattner0132aff2005-05-06 22:57:40 +00004584 <p>The optional "tail" marker indicates whether the callee function accesses
4585 any allocas or varargs in the caller. If the "tail" marker is present, the
Chris Lattnere23c1392005-05-06 05:47:36 +00004586 function call is eligible for tail call optimization. Note that calls may
4587 be marked "tail" even if they do not occur before a <a
Dan Gohmanef9462f2008-10-14 16:51:45 +00004588 href="#i_ret"><tt>ret</tt></a> instruction.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00004589 </li>
4590 <li>
Duncan Sands16f122e2007-03-30 12:22:09 +00004591 <p>The optional "cconv" marker indicates which <a href="#callingconv">calling
Chris Lattner0132aff2005-05-06 22:57:40 +00004592 convention</a> the call should use. If none is specified, the call defaults
Dan Gohmanef9462f2008-10-14 16:51:45 +00004593 to using C calling conventions.</p>
Chris Lattner0132aff2005-05-06 22:57:40 +00004594 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +00004595
4596 <li>
4597 <p>The optional <a href="#paramattrs">Parameter Attributes</a> list for
4598 return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>',
4599 and '<tt>inreg</tt>' attributes are valid here.</p>
4600 </li>
4601
Chris Lattner0132aff2005-05-06 22:57:40 +00004602 <li>
Nick Lewyckya9b13d52007-09-08 13:57:50 +00004603 <p>'<tt>ty</tt>': the type of the call instruction itself which is also
4604 the type of the return value. Functions that return no value are marked
4605 <tt><a href="#t_void">void</a></tt>.</p>
4606 </li>
4607 <li>
4608 <p>'<tt>fnty</tt>': shall be the signature of the pointer to function
4609 value being invoked. The argument types must match the types implied by
4610 this signature. This type can be omitted if the function is not varargs
4611 and if the function type does not return a pointer to a function.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +00004612 </li>
4613 <li>
4614 <p>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
4615 be invoked. In most cases, this is a direct function invocation, but
4616 indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
John Criswell88190562005-05-16 16:17:45 +00004617 to function value.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00004618 </li>
4619 <li>
4620 <p>'<tt>function args</tt>': argument list whose types match the
Reid Spencerd845d162005-05-01 22:22:57 +00004621 function signature argument types. All arguments must be of
4622 <a href="#t_firstclass">first class</a> type. If the function signature
4623 indicates the function accepts a variable number of arguments, the extra
4624 arguments can be specified.</p>
Chris Lattner48b383b02003-11-25 01:02:51 +00004625 </li>
Devang Patel7e9b05e2008-10-06 18:50:38 +00004626 <li>
Devang Patel02256232008-10-07 17:48:33 +00004627 <p>The optional <a href="#fnattrs">function attributes</a> list. Only
Devang Patel7e9b05e2008-10-06 18:50:38 +00004628 '<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
4629 '<tt>readnone</tt>' attributes are valid here.</p>
4630 </li>
Chris Lattnera8292f32002-05-06 22:08:29 +00004631</ol>
Chris Lattnere23c1392005-05-06 05:47:36 +00004632
Chris Lattner2f7c9632001-06-06 20:29:01 +00004633<h5>Semantics:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +00004634
Chris Lattner48b383b02003-11-25 01:02:51 +00004635<p>The '<tt>call</tt>' instruction is used to cause control flow to
4636transfer to a specified function, with its incoming arguments bound to
4637the specified values. Upon a '<tt><a href="#i_ret">ret</a></tt>'
4638instruction in the called function, control flow continues with the
4639instruction after the function call, and the return value of the
Dan Gohmanef9462f2008-10-14 16:51:45 +00004640function is bound to the result argument.</p>
Chris Lattnere23c1392005-05-06 05:47:36 +00004641
Chris Lattner2f7c9632001-06-06 20:29:01 +00004642<h5>Example:</h5>
Chris Lattnere23c1392005-05-06 05:47:36 +00004643
4644<pre>
Nick Lewyckya9b13d52007-09-08 13:57:50 +00004645 %retval = call i32 @test(i32 %argc)
Chris Lattnerfb7c88d2008-03-21 17:24:17 +00004646 call i32 (i8 *, ...)* @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
4647 %X = tail call i32 @foo() <i>; yields i32</i>
4648 %Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
4649 call void %foo(i8 97 signext)
Devang Pateld6cff512008-03-10 20:49:15 +00004650
4651 %struct.A = type { i32, i8 }
Devang Patel7e9b05e2008-10-06 18:50:38 +00004652 %r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohmancc3132e2008-10-04 19:00:07 +00004653 %gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
4654 %gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner6cbe8e92008-10-08 06:26:11 +00004655 %Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijmaneefa7df2008-10-07 10:03:45 +00004656 %ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Chris Lattnere23c1392005-05-06 05:47:36 +00004657</pre>
4658
Misha Brukman76307852003-11-08 01:05:38 +00004659</div>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004660
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004661<!-- _______________________________________________________________________ -->
Chris Lattner6a4a0492004-09-27 21:51:25 +00004662<div class="doc_subsubsection">
Chris Lattner33337472006-01-13 23:26:01 +00004663 <a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004664</div>
4665
Misha Brukman76307852003-11-08 01:05:38 +00004666<div class="doc_text">
Chris Lattner6a4a0492004-09-27 21:51:25 +00004667
Chris Lattner26ca62e2003-10-18 05:51:36 +00004668<h5>Syntax:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004669
4670<pre>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004671 &lt;resultval&gt; = va_arg &lt;va_list*&gt; &lt;arglist&gt;, &lt;argty&gt;
Chris Lattner6a4a0492004-09-27 21:51:25 +00004672</pre>
4673
Chris Lattner26ca62e2003-10-18 05:51:36 +00004674<h5>Overview:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004675
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004676<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Chris Lattner6a4a0492004-09-27 21:51:25 +00004677the "variable argument" area of a function call. It is used to implement the
4678<tt>va_arg</tt> macro in C.</p>
4679
Chris Lattner26ca62e2003-10-18 05:51:36 +00004680<h5>Arguments:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004681
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004682<p>This instruction takes a <tt>va_list*</tt> value and the type of
4683the argument. It returns a value of the specified argument type and
Jeff Cohen222a8a42007-04-29 01:07:00 +00004684increments the <tt>va_list</tt> to point to the next argument. The
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004685actual type of <tt>va_list</tt> is target specific.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004686
Chris Lattner26ca62e2003-10-18 05:51:36 +00004687<h5>Semantics:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004688
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004689<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified
4690type from the specified <tt>va_list</tt> and causes the
4691<tt>va_list</tt> to point to the next argument. For more information,
4692see the variable argument handling <a href="#int_varargs">Intrinsic
4693Functions</a>.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004694
4695<p>It is legal for this instruction to be called in a function which does not
4696take a variable number of arguments, for example, the <tt>vfprintf</tt>
Misha Brukman76307852003-11-08 01:05:38 +00004697function.</p>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004698
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004699<p><tt>va_arg</tt> is an LLVM instruction instead of an <a
John Criswell88190562005-05-16 16:17:45 +00004700href="#intrinsics">intrinsic function</a> because it takes a type as an
Chris Lattner6a4a0492004-09-27 21:51:25 +00004701argument.</p>
4702
Chris Lattner26ca62e2003-10-18 05:51:36 +00004703<h5>Example:</h5>
Chris Lattner6a4a0492004-09-27 21:51:25 +00004704
4705<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
4706
Dan Gohman3065b612009-01-12 23:12:39 +00004707<p>Note that the code generator does not yet fully support va_arg
4708 on many targets. Also, it does not currently support va_arg with
4709 aggregate types on any target.</p>
4710
Misha Brukman76307852003-11-08 01:05:38 +00004711</div>
Chris Lattner941515c2004-01-06 05:31:32 +00004712
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004713<!-- *********************************************************************** -->
Chris Lattner48b383b02003-11-25 01:02:51 +00004714<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
4715<!-- *********************************************************************** -->
Chris Lattner941515c2004-01-06 05:31:32 +00004716
Misha Brukman76307852003-11-08 01:05:38 +00004717<div class="doc_text">
Chris Lattnerfee11462004-02-12 17:01:32 +00004718
4719<p>LLVM supports the notion of an "intrinsic function". These functions have
Reid Spencer4eefaab2007-04-01 08:04:23 +00004720well known names and semantics and are required to follow certain restrictions.
4721Overall, these intrinsics represent an extension mechanism for the LLVM
Jeff Cohen222a8a42007-04-29 01:07:00 +00004722language that does not require changing all of the transformations in LLVM when
Gabor Greifa54634a2007-07-06 22:07:22 +00004723adding to the language (or the bitcode reader/writer, the parser, etc...).</p>
Chris Lattnerfee11462004-02-12 17:01:32 +00004724
John Criswell88190562005-05-16 16:17:45 +00004725<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Jeff Cohen222a8a42007-04-29 01:07:00 +00004726prefix is reserved in LLVM for intrinsic names; thus, function names may not
4727begin with this prefix. Intrinsic functions must always be external functions:
4728you cannot define the body of intrinsic functions. Intrinsic functions may
4729only be used in call or invoke instructions: it is illegal to take the address
4730of an intrinsic function. Additionally, because intrinsic functions are part
4731of the LLVM language, it is required if any are added that they be documented
4732here.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +00004733
Chandler Carruth7132e002007-08-04 01:51:18 +00004734<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents
4735a family of functions that perform the same operation but on different data
4736types. Because LLVM can represent over 8 million different integer types,
4737overloading is used commonly to allow an intrinsic function to operate on any
4738integer type. One or more of the argument types or the result type can be
4739overloaded to accept any integer type. Argument types may also be defined as
4740exactly matching a previous argument's type or the result type. This allows an
4741intrinsic function which accepts multiple arguments, but needs all of them to
4742be of the same type, to only be overloaded with respect to a single argument or
4743the result.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +00004744
Chandler Carruth7132e002007-08-04 01:51:18 +00004745<p>Overloaded intrinsics will have the names of its overloaded argument types
4746encoded into its function name, each preceded by a period. Only those types
4747which are overloaded result in a name suffix. Arguments whose type is matched
4748against another type do not. For example, the <tt>llvm.ctpop</tt> function can
4749take an integer of any width and returns an integer of exactly the same integer
4750width. This leads to a family of functions such as
4751<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29 %val)</tt>.
4752Only one type, the return type, is overloaded, and only one type suffix is
4753required. Because the argument's type is matched against the return type, it
4754does not require its own name suffix.</p>
Reid Spencer4eefaab2007-04-01 08:04:23 +00004755
4756<p>To learn how to add an intrinsic function, please see the
4757<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.
Chris Lattnerfee11462004-02-12 17:01:32 +00004758</p>
4759
Misha Brukman76307852003-11-08 01:05:38 +00004760</div>
Chris Lattner941515c2004-01-06 05:31:32 +00004761
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004762<!-- ======================================================================= -->
Chris Lattner941515c2004-01-06 05:31:32 +00004763<div class="doc_subsection">
4764 <a name="int_varargs">Variable Argument Handling Intrinsics</a>
4765</div>
4766
Misha Brukman76307852003-11-08 01:05:38 +00004767<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +00004768
Misha Brukman76307852003-11-08 01:05:38 +00004769<p>Variable argument support is defined in LLVM with the <a
Chris Lattner33337472006-01-13 23:26:01 +00004770 href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
Chris Lattner48b383b02003-11-25 01:02:51 +00004771intrinsic functions. These functions are related to the similarly
4772named macros defined in the <tt>&lt;stdarg.h&gt;</tt> header file.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004773
Chris Lattner48b383b02003-11-25 01:02:51 +00004774<p>All of these functions operate on arguments that use a
4775target-specific value type "<tt>va_list</tt>". The LLVM assembly
4776language reference manual does not define what this type is, so all
Jeff Cohen222a8a42007-04-29 01:07:00 +00004777transformations should be prepared to handle these functions regardless of
4778the type used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004779
Chris Lattner30b868d2006-05-15 17:26:46 +00004780<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Chris Lattner48b383b02003-11-25 01:02:51 +00004781instruction and the variable argument handling intrinsic functions are
4782used.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004783
Bill Wendling3716c5d2007-05-29 09:04:49 +00004784<div class="doc_code">
Chris Lattnerfee11462004-02-12 17:01:32 +00004785<pre>
Anton Korobeynikov640bbe02007-03-21 23:58:04 +00004786define i32 @test(i32 %X, ...) {
Chris Lattnerfee11462004-02-12 17:01:32 +00004787 ; Initialize variable argument processing
Jeff Cohen222a8a42007-04-29 01:07:00 +00004788 %ap = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004789 %ap2 = bitcast i8** %ap to i8*
Anton Korobeynikov640bbe02007-03-21 23:58:04 +00004790 call void @llvm.va_start(i8* %ap2)
Chris Lattnerfee11462004-02-12 17:01:32 +00004791
4792 ; Read a single integer argument
Jeff Cohen222a8a42007-04-29 01:07:00 +00004793 %tmp = va_arg i8** %ap, i32
Chris Lattnerfee11462004-02-12 17:01:32 +00004794
4795 ; Demonstrate usage of llvm.va_copy and llvm.va_end
Jeff Cohen222a8a42007-04-29 01:07:00 +00004796 %aq = alloca i8*
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004797 %aq2 = bitcast i8** %aq to i8*
Jeff Cohen222a8a42007-04-29 01:07:00 +00004798 call void @llvm.va_copy(i8* %aq2, i8* %ap2)
Anton Korobeynikov640bbe02007-03-21 23:58:04 +00004799 call void @llvm.va_end(i8* %aq2)
Chris Lattnerfee11462004-02-12 17:01:32 +00004800
4801 ; Stop processing of arguments.
Anton Korobeynikov640bbe02007-03-21 23:58:04 +00004802 call void @llvm.va_end(i8* %ap2)
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00004803 ret i32 %tmp
Chris Lattnerfee11462004-02-12 17:01:32 +00004804}
Anton Korobeynikov640bbe02007-03-21 23:58:04 +00004805
4806declare void @llvm.va_start(i8*)
4807declare void @llvm.va_copy(i8*, i8*)
4808declare void @llvm.va_end(i8*)
Chris Lattnerfee11462004-02-12 17:01:32 +00004809</pre>
Misha Brukman76307852003-11-08 01:05:38 +00004810</div>
Chris Lattner941515c2004-01-06 05:31:32 +00004811
Bill Wendling3716c5d2007-05-29 09:04:49 +00004812</div>
4813
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004814<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +00004815<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00004816 <a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +00004817</div>
4818
4819
Misha Brukman76307852003-11-08 01:05:38 +00004820<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004821<h5>Syntax:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004822<pre> declare void %llvm.va_start(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004823<h5>Overview:</h5>
Dan Gohmanef9462f2008-10-14 16:51:45 +00004824<p>The '<tt>llvm.va_start</tt>' intrinsic initializes
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004825<tt>*&lt;arglist&gt;</tt> for subsequent use by <tt><a
4826href="#i_va_arg">va_arg</a></tt>.</p>
4827
4828<h5>Arguments:</h5>
4829
Dan Gohmanef9462f2008-10-14 16:51:45 +00004830<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004831
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004832<h5>Semantics:</h5>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004833
Dan Gohmanef9462f2008-10-14 16:51:45 +00004834<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004835macro available in C. In a target-dependent way, it initializes the
Jeff Cohen222a8a42007-04-29 01:07:00 +00004836<tt>va_list</tt> element to which the argument points, so that the next call to
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004837<tt>va_arg</tt> will produce the first variable argument passed to the function.
4838Unlike the C <tt>va_start</tt> macro, this intrinsic does not need to know the
Jeff Cohen222a8a42007-04-29 01:07:00 +00004839last argument of the function as the compiler can figure that out.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004840
Misha Brukman76307852003-11-08 01:05:38 +00004841</div>
Chris Lattner941515c2004-01-06 05:31:32 +00004842
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004843<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +00004844<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00004845 <a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +00004846</div>
4847
Misha Brukman76307852003-11-08 01:05:38 +00004848<div class="doc_text">
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004849<h5>Syntax:</h5>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00004850<pre> declare void @llvm.va_end(i8* &lt;arglist&gt;)<br></pre>
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004851<h5>Overview:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004852
Jeff Cohen222a8a42007-04-29 01:07:00 +00004853<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*&lt;arglist&gt;</tt>,
Reid Spencer96a5f022007-04-04 02:42:35 +00004854which has been initialized previously with <tt><a href="#int_va_start">llvm.va_start</a></tt>
Chris Lattner48b383b02003-11-25 01:02:51 +00004855or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004856
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004857<h5>Arguments:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004858
Jeff Cohen222a8a42007-04-29 01:07:00 +00004859<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004860
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004861<h5>Semantics:</h5>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004862
Misha Brukman76307852003-11-08 01:05:38 +00004863<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Jeff Cohen222a8a42007-04-29 01:07:00 +00004864macro available in C. In a target-dependent way, it destroys the
4865<tt>va_list</tt> element to which the argument points. Calls to <a
4866href="#int_va_start"><tt>llvm.va_start</tt></a> and <a href="#int_va_copy">
4867<tt>llvm.va_copy</tt></a> must be matched exactly with calls to
4868<tt>llvm.va_end</tt>.</p>
Chris Lattnerdb0790c2007-01-08 07:55:15 +00004869
Misha Brukman76307852003-11-08 01:05:38 +00004870</div>
Chris Lattner941515c2004-01-06 05:31:32 +00004871
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004872<!-- _______________________________________________________________________ -->
Chris Lattner941515c2004-01-06 05:31:32 +00004873<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00004874 <a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
Chris Lattner941515c2004-01-06 05:31:32 +00004875</div>
4876
Misha Brukman76307852003-11-08 01:05:38 +00004877<div class="doc_text">
Chris Lattner757528b0b2004-05-23 21:06:01 +00004878
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004879<h5>Syntax:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004880
4881<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00004882 declare void @llvm.va_copy(i8* &lt;destarglist&gt;, i8* &lt;srcarglist&gt;)
Chris Lattner757528b0b2004-05-23 21:06:01 +00004883</pre>
4884
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004885<h5>Overview:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004886
Jeff Cohen222a8a42007-04-29 01:07:00 +00004887<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
4888from the source argument list to the destination argument list.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004889
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004890<h5>Arguments:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004891
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004892<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Andrew Lenharth5305ea52005-06-22 20:38:11 +00004893The second argument is a pointer to a <tt>va_list</tt> element to copy from.</p>
Andrew Lenharth5fb787c2005-06-18 18:28:17 +00004894
Chris Lattner757528b0b2004-05-23 21:06:01 +00004895
Chris Lattnerbd64b4e2003-05-08 04:57:36 +00004896<h5>Semantics:</h5>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004897
Jeff Cohen222a8a42007-04-29 01:07:00 +00004898<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
4899macro available in C. In a target-dependent way, it copies the source
4900<tt>va_list</tt> element into the destination <tt>va_list</tt> element. This
4901intrinsic is necessary because the <tt><a href="#int_va_start">
4902llvm.va_start</a></tt> intrinsic may be arbitrarily complex and require, for
4903example, memory allocation.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004904
Misha Brukman76307852003-11-08 01:05:38 +00004905</div>
Chris Lattner941515c2004-01-06 05:31:32 +00004906
Chris Lattnerfee11462004-02-12 17:01:32 +00004907<!-- ======================================================================= -->
4908<div class="doc_subsection">
Chris Lattner757528b0b2004-05-23 21:06:01 +00004909 <a name="int_gc">Accurate Garbage Collection Intrinsics</a>
4910</div>
4911
4912<div class="doc_text">
4913
4914<p>
4915LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner67c37d12008-08-05 18:29:16 +00004916Collection</a> (GC) requires the implementation and generation of these
4917intrinsics.
Reid Spencer96a5f022007-04-04 02:42:35 +00004918These intrinsics allow identification of <a href="#int_gcroot">GC roots on the
Chris Lattner757528b0b2004-05-23 21:06:01 +00004919stack</a>, as well as garbage collector implementations that require <a
Reid Spencer96a5f022007-04-04 02:42:35 +00004920href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a> barriers.
Chris Lattner757528b0b2004-05-23 21:06:01 +00004921Front-ends for type-safe garbage collected languages should generate these
4922intrinsics to make use of the LLVM garbage collectors. For more details, see <a
4923href="GarbageCollection.html">Accurate Garbage Collection with LLVM</a>.
4924</p>
Christopher Lamb55c6d4f2007-12-17 01:00:21 +00004925
4926<p>The garbage collection intrinsics only operate on objects in the generic
4927 address space (address space zero).</p>
4928
Chris Lattner757528b0b2004-05-23 21:06:01 +00004929</div>
4930
4931<!-- _______________________________________________________________________ -->
4932<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00004933 <a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004934</div>
4935
4936<div class="doc_text">
4937
4938<h5>Syntax:</h5>
4939
4940<pre>
Chris Lattner12477732007-09-21 17:30:40 +00004941 declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Chris Lattner757528b0b2004-05-23 21:06:01 +00004942</pre>
4943
4944<h5>Overview:</h5>
4945
John Criswelldfe6a862004-12-10 15:51:16 +00004946<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Chris Lattner757528b0b2004-05-23 21:06:01 +00004947the code generator, and allows some metadata to be associated with it.</p>
4948
4949<h5>Arguments:</h5>
4950
4951<p>The first argument specifies the address of a stack object that contains the
4952root pointer. The second pointer (which must be either a constant or a global
4953value address) contains the meta-data to be associated with the root.</p>
4954
4955<h5>Semantics:</h5>
4956
Chris Lattner851b7712008-04-24 05:59:56 +00004957<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Chris Lattner757528b0b2004-05-23 21:06:01 +00004958location. At compile-time, the code generator generates information to allow
Gordon Henriksenfb56bde2007-12-25 02:31:26 +00004959the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
4960intrinsic may only be used in a function which <a href="#gc">specifies a GC
4961algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004962
4963</div>
4964
4965
4966<!-- _______________________________________________________________________ -->
4967<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00004968 <a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004969</div>
4970
4971<div class="doc_text">
4972
4973<h5>Syntax:</h5>
4974
4975<pre>
Chris Lattner12477732007-09-21 17:30:40 +00004976 declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Chris Lattner757528b0b2004-05-23 21:06:01 +00004977</pre>
4978
4979<h5>Overview:</h5>
4980
4981<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
4982locations, allowing garbage collector implementations that require read
4983barriers.</p>
4984
4985<h5>Arguments:</h5>
4986
Chris Lattnerf9228072006-03-14 20:02:51 +00004987<p>The second argument is the address to read from, which should be an address
4988allocated from the garbage collector. The first object is a pointer to the
4989start of the referenced object, if needed by the language runtime (otherwise
4990null).</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004991
4992<h5>Semantics:</h5>
4993
4994<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
4995instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +00004996garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
4997may only be used in a function which <a href="#gc">specifies a GC
4998algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00004999
5000</div>
5001
5002
5003<!-- _______________________________________________________________________ -->
5004<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005005 <a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
Chris Lattner757528b0b2004-05-23 21:06:01 +00005006</div>
5007
5008<div class="doc_text">
5009
5010<h5>Syntax:</h5>
5011
5012<pre>
Chris Lattner12477732007-09-21 17:30:40 +00005013 declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Chris Lattner757528b0b2004-05-23 21:06:01 +00005014</pre>
5015
5016<h5>Overview:</h5>
5017
5018<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
5019locations, allowing garbage collector implementations that require write
5020barriers (such as generational or reference counting collectors).</p>
5021
5022<h5>Arguments:</h5>
5023
Chris Lattnerf9228072006-03-14 20:02:51 +00005024<p>The first argument is the reference to store, the second is the start of the
5025object to store it to, and the third is the address of the field of Obj to
5026store to. If the runtime does not require a pointer to the object, Obj may be
5027null.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00005028
5029<h5>Semantics:</h5>
5030
5031<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
5032instruction, but may be replaced with substantially more complex code by the
Gordon Henriksenfb56bde2007-12-25 02:31:26 +00005033garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
5034may only be used in a function which <a href="#gc">specifies a GC
5035algorithm</a>.</p>
Chris Lattner757528b0b2004-05-23 21:06:01 +00005036
5037</div>
5038
5039
5040
5041<!-- ======================================================================= -->
5042<div class="doc_subsection">
Chris Lattner3649c3a2004-02-14 04:08:35 +00005043 <a name="int_codegen">Code Generator Intrinsics</a>
5044</div>
5045
5046<div class="doc_text">
5047<p>
5048These intrinsics are provided by LLVM to expose special features that may only
5049be implemented with code generator support.
5050</p>
5051
5052</div>
5053
5054<!-- _______________________________________________________________________ -->
5055<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005056 <a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +00005057</div>
5058
5059<div class="doc_text">
5060
5061<h5>Syntax:</h5>
5062<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005063 declare i8 *@llvm.returnaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +00005064</pre>
5065
5066<h5>Overview:</h5>
5067
5068<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +00005069The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
5070target-specific value indicating the return address of the current function
5071or one of its callers.
Chris Lattner3649c3a2004-02-14 04:08:35 +00005072</p>
5073
5074<h5>Arguments:</h5>
5075
5076<p>
5077The argument to this intrinsic indicates which function to return the address
5078for. Zero indicates the calling function, one indicates its caller, etc. The
5079argument is <b>required</b> to be a constant integer value.
5080</p>
5081
5082<h5>Semantics:</h5>
5083
5084<p>
5085The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer indicating
5086the return address of the specified call frame, or zero if it cannot be
5087identified. The value returned by this intrinsic is likely to be incorrect or 0
5088for arguments other than zero, so it should only be used for debugging purposes.
5089</p>
5090
5091<p>
5092Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +00005093aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +00005094source-language caller.
5095</p>
5096</div>
5097
5098
5099<!-- _______________________________________________________________________ -->
5100<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005101 <a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +00005102</div>
5103
5104<div class="doc_text">
5105
5106<h5>Syntax:</h5>
5107<pre>
Chris Lattner12477732007-09-21 17:30:40 +00005108 declare i8 *@llvm.frameaddress(i32 &lt;level&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +00005109</pre>
5110
5111<h5>Overview:</h5>
5112
5113<p>
Chris Lattnerc1fb4262006-10-15 20:05:59 +00005114The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
5115target-specific frame pointer value for the specified stack frame.
Chris Lattner3649c3a2004-02-14 04:08:35 +00005116</p>
5117
5118<h5>Arguments:</h5>
5119
5120<p>
5121The argument to this intrinsic indicates which function to return the frame
5122pointer for. Zero indicates the calling function, one indicates its caller,
5123etc. The argument is <b>required</b> to be a constant integer value.
5124</p>
5125
5126<h5>Semantics:</h5>
5127
5128<p>
5129The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer indicating
5130the frame address of the specified call frame, or zero if it cannot be
5131identified. The value returned by this intrinsic is likely to be incorrect or 0
5132for arguments other than zero, so it should only be used for debugging purposes.
5133</p>
5134
5135<p>
5136Note that calling this intrinsic does not prevent function inlining or other
Chris Lattner2e6eb5f2005-03-07 20:30:51 +00005137aggressive transformations, so the value returned may not be that of the obvious
Chris Lattner3649c3a2004-02-14 04:08:35 +00005138source-language caller.
5139</p>
5140</div>
5141
Chris Lattnerc8a2c222005-02-28 19:24:19 +00005142<!-- _______________________________________________________________________ -->
5143<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005144 <a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +00005145</div>
5146
5147<div class="doc_text">
5148
5149<h5>Syntax:</h5>
5150<pre>
Chris Lattner12477732007-09-21 17:30:40 +00005151 declare i8 *@llvm.stacksave()
Chris Lattner2f0f0012006-01-13 02:03:13 +00005152</pre>
5153
5154<h5>Overview:</h5>
5155
5156<p>
5157The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state of
Reid Spencer96a5f022007-04-04 02:42:35 +00005158the function stack, for use with <a href="#int_stackrestore">
Chris Lattner2f0f0012006-01-13 02:03:13 +00005159<tt>llvm.stackrestore</tt></a>. This is useful for implementing language
5160features like scoped automatic variable sized arrays in C99.
5161</p>
5162
5163<h5>Semantics:</h5>
5164
5165<p>
5166This intrinsic returns a opaque pointer value that can be passed to <a
Reid Spencer96a5f022007-04-04 02:42:35 +00005167href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When an
Chris Lattner2f0f0012006-01-13 02:03:13 +00005168<tt>llvm.stackrestore</tt> intrinsic is executed with a value saved from
5169<tt>llvm.stacksave</tt>, it effectively restores the state of the stack to the
5170state it was in when the <tt>llvm.stacksave</tt> intrinsic executed. In
5171practice, this pops any <a href="#i_alloca">alloca</a> blocks from the stack
5172that were allocated after the <tt>llvm.stacksave</tt> was executed.
5173</p>
5174
5175</div>
5176
5177<!-- _______________________________________________________________________ -->
5178<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005179 <a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
Chris Lattner2f0f0012006-01-13 02:03:13 +00005180</div>
5181
5182<div class="doc_text">
5183
5184<h5>Syntax:</h5>
5185<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005186 declare void @llvm.stackrestore(i8 * %ptr)
Chris Lattner2f0f0012006-01-13 02:03:13 +00005187</pre>
5188
5189<h5>Overview:</h5>
5190
5191<p>
5192The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
5193the function stack to the state it was in when the corresponding <a
Reid Spencer96a5f022007-04-04 02:42:35 +00005194href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic executed. This is
Chris Lattner2f0f0012006-01-13 02:03:13 +00005195useful for implementing language features like scoped automatic variable sized
5196arrays in C99.
5197</p>
5198
5199<h5>Semantics:</h5>
5200
5201<p>
Reid Spencer96a5f022007-04-04 02:42:35 +00005202See the description for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.
Chris Lattner2f0f0012006-01-13 02:03:13 +00005203</p>
5204
5205</div>
5206
5207
5208<!-- _______________________________________________________________________ -->
5209<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005210 <a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
Chris Lattnerc8a2c222005-02-28 19:24:19 +00005211</div>
5212
5213<div class="doc_text">
5214
5215<h5>Syntax:</h5>
5216<pre>
Chris Lattner12477732007-09-21 17:30:40 +00005217 declare void @llvm.prefetch(i8* &lt;address&gt;, i32 &lt;rw&gt;, i32 &lt;locality&gt;)
Chris Lattnerc8a2c222005-02-28 19:24:19 +00005218</pre>
5219
5220<h5>Overview:</h5>
5221
5222
5223<p>
5224The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to insert
John Criswell88190562005-05-16 16:17:45 +00005225a prefetch instruction if supported; otherwise, it is a noop. Prefetches have
5226no
5227effect on the behavior of the program but can change its performance
Chris Lattnerff851072005-02-28 19:47:14 +00005228characteristics.
Chris Lattnerc8a2c222005-02-28 19:24:19 +00005229</p>
5230
5231<h5>Arguments:</h5>
5232
5233<p>
5234<tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the specifier
5235determining if the fetch should be for a read (0) or write (1), and
5236<tt>locality</tt> is a temporal locality specifier ranging from (0) - no
Chris Lattnerd3e641c2005-03-07 20:31:38 +00005237locality, to (3) - extremely local keep in cache. The <tt>rw</tt> and
Chris Lattnerc8a2c222005-02-28 19:24:19 +00005238<tt>locality</tt> arguments must be constant integers.
5239</p>
5240
5241<h5>Semantics:</h5>
5242
5243<p>
5244This intrinsic does not modify the behavior of the program. In particular,
5245prefetches cannot trap and do not produce a value. On targets that support this
5246intrinsic, the prefetch can provide hints to the processor cache for better
5247performance.
5248</p>
5249
5250</div>
5251
Andrew Lenharthb4427912005-03-28 20:05:49 +00005252<!-- _______________________________________________________________________ -->
5253<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005254 <a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
Andrew Lenharthb4427912005-03-28 20:05:49 +00005255</div>
5256
5257<div class="doc_text">
5258
5259<h5>Syntax:</h5>
5260<pre>
Chris Lattner12477732007-09-21 17:30:40 +00005261 declare void @llvm.pcmarker(i32 &lt;id&gt;)
Andrew Lenharthb4427912005-03-28 20:05:49 +00005262</pre>
5263
5264<h5>Overview:</h5>
5265
5266
5267<p>
John Criswell88190562005-05-16 16:17:45 +00005268The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program Counter
Chris Lattner67c37d12008-08-05 18:29:16 +00005269(PC) in a region of
5270code to simulators and other tools. The method is target specific, but it is
5271expected that the marker will use exported symbols to transmit the PC of the
5272marker.
5273The marker makes no guarantees that it will remain with any specific instruction
5274after optimizations. It is possible that the presence of a marker will inhibit
Chris Lattnerb40261e2006-03-24 07:16:10 +00005275optimizations. The intended use is to be inserted after optimizations to allow
John Criswell88190562005-05-16 16:17:45 +00005276correlations of simulation runs.
Andrew Lenharthb4427912005-03-28 20:05:49 +00005277</p>
5278
5279<h5>Arguments:</h5>
5280
5281<p>
5282<tt>id</tt> is a numerical id identifying the marker.
5283</p>
5284
5285<h5>Semantics:</h5>
5286
5287<p>
5288This intrinsic does not modify the behavior of the program. Backends that do not
5289support this intrinisic may ignore it.
5290</p>
5291
5292</div>
5293
Andrew Lenharth01aa5632005-11-11 16:47:30 +00005294<!-- _______________________________________________________________________ -->
5295<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005296 <a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
Andrew Lenharth01aa5632005-11-11 16:47:30 +00005297</div>
5298
5299<div class="doc_text">
5300
5301<h5>Syntax:</h5>
5302<pre>
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005303 declare i64 @llvm.readcyclecounter( )
Andrew Lenharth01aa5632005-11-11 16:47:30 +00005304</pre>
5305
5306<h5>Overview:</h5>
5307
5308
5309<p>
5310The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
5311counter register (or similar low latency, high accuracy clocks) on those targets
5312that support it. On X86, it should map to RDTSC. On Alpha, it should map to RPCC.
5313As the backing counters overflow quickly (on the order of 9 seconds on alpha), this
5314should only be used for small timings.
5315</p>
5316
5317<h5>Semantics:</h5>
5318
5319<p>
5320When directly supported, reading the cycle counter should not modify any memory.
5321Implementations are allowed to either return a application specific value or a
5322system wide value. On backends without support, this is lowered to a constant 0.
5323</p>
5324
5325</div>
5326
Chris Lattner3649c3a2004-02-14 04:08:35 +00005327<!-- ======================================================================= -->
5328<div class="doc_subsection">
Chris Lattnerfee11462004-02-12 17:01:32 +00005329 <a name="int_libc">Standard C Library Intrinsics</a>
5330</div>
5331
5332<div class="doc_text">
5333<p>
Chris Lattner3649c3a2004-02-14 04:08:35 +00005334LLVM provides intrinsics for a few important standard C library functions.
5335These intrinsics allow source-language front-ends to pass information about the
5336alignment of the pointer arguments to the code generator, providing opportunity
5337for more efficient code generation.
Chris Lattnerfee11462004-02-12 17:01:32 +00005338</p>
5339
5340</div>
5341
5342<!-- _______________________________________________________________________ -->
5343<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005344 <a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
Chris Lattnerfee11462004-02-12 17:01:32 +00005345</div>
5346
5347<div class="doc_text">
5348
5349<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +00005350<p>This is an overloaded intrinsic. You can use llvm.memcpy on any integer bit
5351width. Not all targets support all bit widths however.</p>
Chris Lattnerfee11462004-02-12 17:01:32 +00005352<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +00005353 declare void @llvm.memcpy.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5354 i8 &lt;len&gt;, i32 &lt;align&gt;)
5355 declare void @llvm.memcpy.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5356 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005357 declare void @llvm.memcpy.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005358 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005359 declare void @llvm.memcpy.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005360 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerfee11462004-02-12 17:01:32 +00005361</pre>
5362
5363<h5>Overview:</h5>
5364
5365<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005366The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +00005367location to the destination location.
5368</p>
5369
5370<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005371Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
5372intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerfee11462004-02-12 17:01:32 +00005373</p>
5374
5375<h5>Arguments:</h5>
5376
5377<p>
5378The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +00005379the source. The third argument is an integer argument
Chris Lattnerfee11462004-02-12 17:01:32 +00005380specifying the number of bytes to copy, and the fourth argument is the alignment
5381of the source and destination locations.
5382</p>
5383
Chris Lattner4c67c482004-02-12 21:18:15 +00005384<p>
5385If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +00005386the caller guarantees that both the source and destination pointers are aligned
5387to that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +00005388</p>
5389
Chris Lattnerfee11462004-02-12 17:01:32 +00005390<h5>Semantics:</h5>
5391
5392<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005393The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerfee11462004-02-12 17:01:32 +00005394location to the destination location, which are not allowed to overlap. It
5395copies "len" bytes of memory over. If the argument is known to be aligned to
5396some boundary, this can be specified as the fourth argument, otherwise it should
5397be set to 0 or 1.
5398</p>
5399</div>
5400
5401
Chris Lattnerf30152e2004-02-12 18:10:10 +00005402<!-- _______________________________________________________________________ -->
5403<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005404 <a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
Chris Lattnerf30152e2004-02-12 18:10:10 +00005405</div>
5406
5407<div class="doc_text">
5408
5409<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +00005410<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
5411width. Not all targets support all bit widths however.</p>
Chris Lattnerf30152e2004-02-12 18:10:10 +00005412<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +00005413 declare void @llvm.memmove.i8(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5414 i8 &lt;len&gt;, i32 &lt;align&gt;)
5415 declare void @llvm.memmove.i16(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
5416 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005417 declare void @llvm.memmove.i32(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005418 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005419 declare void @llvm.memmove.i64(i8 * &lt;dest&gt;, i8 * &lt;src&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005420 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattnerf30152e2004-02-12 18:10:10 +00005421</pre>
5422
5423<h5>Overview:</h5>
5424
5425<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005426The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the source
5427location to the destination location. It is similar to the
Chris Lattnerec564022008-01-06 19:51:52 +00005428'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to overlap.
Chris Lattnerf30152e2004-02-12 18:10:10 +00005429</p>
5430
5431<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005432Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
5433intrinsics do not return a value, and takes an extra alignment argument.
Chris Lattnerf30152e2004-02-12 18:10:10 +00005434</p>
5435
5436<h5>Arguments:</h5>
5437
5438<p>
5439The first argument is a pointer to the destination, the second is a pointer to
Chris Lattner0c8b2592006-03-03 00:07:20 +00005440the source. The third argument is an integer argument
Chris Lattnerf30152e2004-02-12 18:10:10 +00005441specifying the number of bytes to copy, and the fourth argument is the alignment
5442of the source and destination locations.
5443</p>
5444
Chris Lattner4c67c482004-02-12 21:18:15 +00005445<p>
5446If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +00005447the caller guarantees that the source and destination pointers are aligned to
5448that boundary.
Chris Lattner4c67c482004-02-12 21:18:15 +00005449</p>
5450
Chris Lattnerf30152e2004-02-12 18:10:10 +00005451<h5>Semantics:</h5>
5452
5453<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005454The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the source
Chris Lattnerf30152e2004-02-12 18:10:10 +00005455location to the destination location, which may overlap. It
5456copies "len" bytes of memory over. If the argument is known to be aligned to
5457some boundary, this can be specified as the fourth argument, otherwise it should
5458be set to 0 or 1.
5459</p>
5460</div>
5461
Chris Lattner941515c2004-01-06 05:31:32 +00005462
Chris Lattner3649c3a2004-02-14 04:08:35 +00005463<!-- _______________________________________________________________________ -->
5464<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005465 <a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
Chris Lattner3649c3a2004-02-14 04:08:35 +00005466</div>
5467
5468<div class="doc_text">
5469
5470<h5>Syntax:</h5>
Chris Lattnerdd708342008-11-21 16:42:48 +00005471<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
5472width. Not all targets support all bit widths however.</p>
Chris Lattner3649c3a2004-02-14 04:08:35 +00005473<pre>
Chris Lattnerdd708342008-11-21 16:42:48 +00005474 declare void @llvm.memset.i8(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5475 i8 &lt;len&gt;, i32 &lt;align&gt;)
5476 declare void @llvm.memset.i16(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
5477 i16 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005478 declare void @llvm.memset.i32(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005479 i32 &lt;len&gt;, i32 &lt;align&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005480 declare void @llvm.memset.i64(i8 * &lt;dest&gt;, i8 &lt;val&gt;,
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005481 i64 &lt;len&gt;, i32 &lt;align&gt;)
Chris Lattner3649c3a2004-02-14 04:08:35 +00005482</pre>
5483
5484<h5>Overview:</h5>
5485
5486<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005487The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a particular
Chris Lattner3649c3a2004-02-14 04:08:35 +00005488byte value.
5489</p>
5490
5491<p>
5492Note that, unlike the standard libc function, the <tt>llvm.memset</tt> intrinsic
5493does not return a value, and takes an extra alignment argument.
5494</p>
5495
5496<h5>Arguments:</h5>
5497
5498<p>
5499The first argument is a pointer to the destination to fill, the second is the
Chris Lattner0c8b2592006-03-03 00:07:20 +00005500byte value to fill it with, the third argument is an integer
Chris Lattner3649c3a2004-02-14 04:08:35 +00005501argument specifying the number of bytes to fill, and the fourth argument is the
5502known alignment of destination location.
5503</p>
5504
5505<p>
5506If the call to this intrinisic has an alignment value that is not 0 or 1, then
Chris Lattner5316e5d2006-03-04 00:02:10 +00005507the caller guarantees that the destination pointer is aligned to that boundary.
Chris Lattner3649c3a2004-02-14 04:08:35 +00005508</p>
5509
5510<h5>Semantics:</h5>
5511
5512<p>
Chris Lattner0c8b2592006-03-03 00:07:20 +00005513The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting at
5514the
Chris Lattner3649c3a2004-02-14 04:08:35 +00005515destination location. If the argument is known to be aligned to some boundary,
5516this can be specified as the fourth argument, otherwise it should be set to 0 or
55171.
5518</p>
5519</div>
5520
5521
Chris Lattner3b4f4372004-06-11 02:28:03 +00005522<!-- _______________________________________________________________________ -->
5523<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005524 <a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
Chris Lattner8a8f2e52005-07-21 01:29:16 +00005525</div>
5526
5527<div class="doc_text">
5528
5529<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +00005530<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
Dan Gohmanb6324c12007-10-15 20:30:11 +00005531floating point or vector of floating point type. Not all targets support all
Dan Gohmanef9462f2008-10-14 16:51:45 +00005532types however.</p>
Chris Lattner8a8f2e52005-07-21 01:29:16 +00005533<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +00005534 declare float @llvm.sqrt.f32(float %Val)
5535 declare double @llvm.sqrt.f64(double %Val)
5536 declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
5537 declare fp128 @llvm.sqrt.f128(fp128 %Val)
5538 declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Chris Lattner8a8f2e52005-07-21 01:29:16 +00005539</pre>
5540
5541<h5>Overview:</h5>
5542
5543<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +00005544The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
Dan Gohmanb6324c12007-10-15 20:30:11 +00005545returning the same value as the libm '<tt>sqrt</tt>' functions would. Unlike
Chris Lattner8a8f2e52005-07-21 01:29:16 +00005546<tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined behavior for
Chris Lattner00d7cb92008-01-29 07:00:44 +00005547negative numbers other than -0.0 (which allows for better optimization, because
5548there is no need to worry about errno being set). <tt>llvm.sqrt(-0.0)</tt> is
5549defined to return -0.0 like IEEE sqrt.
Chris Lattner8a8f2e52005-07-21 01:29:16 +00005550</p>
5551
5552<h5>Arguments:</h5>
5553
5554<p>
5555The argument and return value are floating point numbers of the same type.
5556</p>
5557
5558<h5>Semantics:</h5>
5559
5560<p>
Dan Gohman33988db2007-07-16 14:37:41 +00005561This function returns the sqrt of the specified operand if it is a nonnegative
Chris Lattner8a8f2e52005-07-21 01:29:16 +00005562floating point number.
5563</p>
5564</div>
5565
Chris Lattner33b73f92006-09-08 06:34:02 +00005566<!-- _______________________________________________________________________ -->
5567<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005568 <a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
Chris Lattner33b73f92006-09-08 06:34:02 +00005569</div>
5570
5571<div class="doc_text">
5572
5573<h5>Syntax:</h5>
Dale Johannesendd89d272007-10-02 17:47:38 +00005574<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
Dan Gohmanb6324c12007-10-15 20:30:11 +00005575floating point or vector of floating point type. Not all targets support all
Dan Gohmanef9462f2008-10-14 16:51:45 +00005576types however.</p>
Chris Lattner33b73f92006-09-08 06:34:02 +00005577<pre>
Dale Johannesendd89d272007-10-02 17:47:38 +00005578 declare float @llvm.powi.f32(float %Val, i32 %power)
5579 declare double @llvm.powi.f64(double %Val, i32 %power)
5580 declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
5581 declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
5582 declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Chris Lattner33b73f92006-09-08 06:34:02 +00005583</pre>
5584
5585<h5>Overview:</h5>
5586
5587<p>
5588The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
5589specified (positive or negative) power. The order of evaluation of
Dan Gohmanb6324c12007-10-15 20:30:11 +00005590multiplications is not defined. When a vector of floating point type is
5591used, the second argument remains a scalar integer value.
Chris Lattner33b73f92006-09-08 06:34:02 +00005592</p>
5593
5594<h5>Arguments:</h5>
5595
5596<p>
5597The second argument is an integer power, and the first is a value to raise to
5598that power.
5599</p>
5600
5601<h5>Semantics:</h5>
5602
5603<p>
5604This function returns the first value raised to the second power with an
5605unspecified sequence of rounding operations.</p>
5606</div>
5607
Dan Gohmanb6324c12007-10-15 20:30:11 +00005608<!-- _______________________________________________________________________ -->
5609<div class="doc_subsubsection">
5610 <a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
5611</div>
5612
5613<div class="doc_text">
5614
5615<h5>Syntax:</h5>
5616<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
5617floating point or vector of floating point type. Not all targets support all
Dan Gohmanef9462f2008-10-14 16:51:45 +00005618types however.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +00005619<pre>
5620 declare float @llvm.sin.f32(float %Val)
5621 declare double @llvm.sin.f64(double %Val)
5622 declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
5623 declare fp128 @llvm.sin.f128(fp128 %Val)
5624 declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
5625</pre>
5626
5627<h5>Overview:</h5>
5628
5629<p>
5630The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.
5631</p>
5632
5633<h5>Arguments:</h5>
5634
5635<p>
5636The argument and return value are floating point numbers of the same type.
5637</p>
5638
5639<h5>Semantics:</h5>
5640
5641<p>
5642This function returns the sine of the specified operand, returning the
5643same values as the libm <tt>sin</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +00005644conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +00005645</div>
5646
5647<!-- _______________________________________________________________________ -->
5648<div class="doc_subsubsection">
5649 <a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
5650</div>
5651
5652<div class="doc_text">
5653
5654<h5>Syntax:</h5>
5655<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
5656floating point or vector of floating point type. Not all targets support all
Dan Gohmanef9462f2008-10-14 16:51:45 +00005657types however.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +00005658<pre>
5659 declare float @llvm.cos.f32(float %Val)
5660 declare double @llvm.cos.f64(double %Val)
5661 declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
5662 declare fp128 @llvm.cos.f128(fp128 %Val)
5663 declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
5664</pre>
5665
5666<h5>Overview:</h5>
5667
5668<p>
5669The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.
5670</p>
5671
5672<h5>Arguments:</h5>
5673
5674<p>
5675The argument and return value are floating point numbers of the same type.
5676</p>
5677
5678<h5>Semantics:</h5>
5679
5680<p>
5681This function returns the cosine of the specified operand, returning the
5682same values as the libm <tt>cos</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +00005683conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +00005684</div>
5685
5686<!-- _______________________________________________________________________ -->
5687<div class="doc_subsubsection">
5688 <a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
5689</div>
5690
5691<div class="doc_text">
5692
5693<h5>Syntax:</h5>
5694<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
5695floating point or vector of floating point type. Not all targets support all
Dan Gohmanef9462f2008-10-14 16:51:45 +00005696types however.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +00005697<pre>
5698 declare float @llvm.pow.f32(float %Val, float %Power)
5699 declare double @llvm.pow.f64(double %Val, double %Power)
5700 declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
5701 declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
5702 declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
5703</pre>
5704
5705<h5>Overview:</h5>
5706
5707<p>
5708The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
5709specified (positive or negative) power.
5710</p>
5711
5712<h5>Arguments:</h5>
5713
5714<p>
5715The second argument is a floating point power, and the first is a value to
5716raise to that power.
5717</p>
5718
5719<h5>Semantics:</h5>
5720
5721<p>
5722This function returns the first value raised to the second power,
5723returning the
5724same values as the libm <tt>pow</tt> functions would, and handles error
Dan Gohmand0806a02007-10-17 18:05:13 +00005725conditions in the same way.</p>
Dan Gohmanb6324c12007-10-15 20:30:11 +00005726</div>
5727
Chris Lattner33b73f92006-09-08 06:34:02 +00005728
Andrew Lenharth1d463522005-05-03 18:01:48 +00005729<!-- ======================================================================= -->
5730<div class="doc_subsection">
Nate Begeman0f223bb2006-01-13 23:26:38 +00005731 <a name="int_manip">Bit Manipulation Intrinsics</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +00005732</div>
5733
5734<div class="doc_text">
5735<p>
Nate Begeman0f223bb2006-01-13 23:26:38 +00005736LLVM provides intrinsics for a few important bit manipulation operations.
Andrew Lenharth1d463522005-05-03 18:01:48 +00005737These allow efficient code generation for some algorithms.
5738</p>
5739
5740</div>
5741
5742<!-- _______________________________________________________________________ -->
5743<div class="doc_subsubsection">
Reid Spencer96a5f022007-04-04 02:42:35 +00005744 <a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
Nate Begeman0f223bb2006-01-13 23:26:38 +00005745</div>
5746
5747<div class="doc_text">
5748
5749<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +00005750<p>This is an overloaded intrinsic function. You can use bswap on any integer
Dan Gohmanef9462f2008-10-14 16:51:45 +00005751type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
Nate Begeman0f223bb2006-01-13 23:26:38 +00005752<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +00005753 declare i16 @llvm.bswap.i16(i16 &lt;id&gt;)
5754 declare i32 @llvm.bswap.i32(i32 &lt;id&gt;)
5755 declare i64 @llvm.bswap.i64(i64 &lt;id&gt;)
Nate Begeman0f223bb2006-01-13 23:26:38 +00005756</pre>
5757
5758<h5>Overview:</h5>
5759
5760<p>
Reid Spencerf361c4f2007-04-02 02:25:19 +00005761The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
Reid Spencer4eefaab2007-04-01 08:04:23 +00005762values with an even number of bytes (positive multiple of 16 bits). These are
5763useful for performing operations on data that is not in the target's native
5764byte order.
Nate Begeman0f223bb2006-01-13 23:26:38 +00005765</p>
5766
5767<h5>Semantics:</h5>
5768
5769<p>
Chandler Carruth7132e002007-08-04 01:51:18 +00005770The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005771and low byte of the input i16 swapped. Similarly, the <tt>llvm.bswap.i32</tt>
5772intrinsic returns an i32 value that has the four bytes of the input i32
5773swapped, so that if the input bytes are numbered 0, 1, 2, 3 then the returned
Chandler Carruth7132e002007-08-04 01:51:18 +00005774i32 will have its bytes in 3, 2, 1, 0 order. The <tt>llvm.bswap.i48</tt>,
5775<tt>llvm.bswap.i64</tt> and other intrinsics extend this concept to
Reid Spencer4eefaab2007-04-01 08:04:23 +00005776additional even-byte lengths (6 bytes, 8 bytes and more, respectively).
Nate Begeman0f223bb2006-01-13 23:26:38 +00005777</p>
5778
5779</div>
5780
5781<!-- _______________________________________________________________________ -->
5782<div class="doc_subsubsection">
Reid Spencerb4f9a6f2006-01-16 21:12:35 +00005783 <a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +00005784</div>
5785
5786<div class="doc_text">
5787
5788<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +00005789<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Dan Gohmanef9462f2008-10-14 16:51:45 +00005790width. Not all targets support all bit widths however.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +00005791<pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005792 declare i8 @llvm.ctpop.i8(i8 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +00005793 declare i16 @llvm.ctpop.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005794 declare i32 @llvm.ctpop.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +00005795 declare i64 @llvm.ctpop.i64(i64 &lt;src&gt;)
5796 declare i256 @llvm.ctpop.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +00005797</pre>
5798
5799<h5>Overview:</h5>
5800
5801<p>
Chris Lattner069b5bd2006-01-16 22:38:59 +00005802The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set in a
5803value.
Andrew Lenharth1d463522005-05-03 18:01:48 +00005804</p>
5805
5806<h5>Arguments:</h5>
5807
5808<p>
Chris Lattner573f64e2005-05-07 01:46:40 +00005809The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +00005810integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +00005811</p>
5812
5813<h5>Semantics:</h5>
5814
5815<p>
5816The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.
5817</p>
5818</div>
5819
5820<!-- _______________________________________________________________________ -->
5821<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +00005822 <a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
Andrew Lenharth1d463522005-05-03 18:01:48 +00005823</div>
5824
5825<div class="doc_text">
5826
5827<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +00005828<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
Dan Gohmanef9462f2008-10-14 16:51:45 +00005829integer bit width. Not all targets support all bit widths however.</p>
Andrew Lenharth1d463522005-05-03 18:01:48 +00005830<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +00005831 declare i8 @llvm.ctlz.i8 (i8 &lt;src&gt;)
5832 declare i16 @llvm.ctlz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005833 declare i32 @llvm.ctlz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +00005834 declare i64 @llvm.ctlz.i64(i64 &lt;src&gt;)
5835 declare i256 @llvm.ctlz.i256(i256 &lt;src&gt;)
Andrew Lenharth1d463522005-05-03 18:01:48 +00005836</pre>
5837
5838<h5>Overview:</h5>
5839
5840<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +00005841The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
5842leading zeros in a variable.
Andrew Lenharth1d463522005-05-03 18:01:48 +00005843</p>
5844
5845<h5>Arguments:</h5>
5846
5847<p>
Chris Lattner573f64e2005-05-07 01:46:40 +00005848The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +00005849integer type. The return type must match the argument type.
Andrew Lenharth1d463522005-05-03 18:01:48 +00005850</p>
5851
5852<h5>Semantics:</h5>
5853
5854<p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005855The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant) zeros
5856in a variable. If the src == 0 then the result is the size in bits of the type
Reid Spencerb5ebf3d2006-12-31 07:07:53 +00005857of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.
Andrew Lenharth1d463522005-05-03 18:01:48 +00005858</p>
5859</div>
Chris Lattner3b4f4372004-06-11 02:28:03 +00005860
5861
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005862
5863<!-- _______________________________________________________________________ -->
5864<div class="doc_subsubsection">
Chris Lattnerb748c672006-01-16 22:34:14 +00005865 <a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005866</div>
5867
5868<div class="doc_text">
5869
5870<h5>Syntax:</h5>
Reid Spencer4eefaab2007-04-01 08:04:23 +00005871<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
Dan Gohmanef9462f2008-10-14 16:51:45 +00005872integer bit width. Not all targets support all bit widths however.</p>
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005873<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +00005874 declare i8 @llvm.cttz.i8 (i8 &lt;src&gt;)
5875 declare i16 @llvm.cttz.i16(i16 &lt;src&gt;)
Anton Korobeynikovbe9c93c2007-03-22 00:02:17 +00005876 declare i32 @llvm.cttz.i32(i32 &lt;src&gt;)
Chandler Carruth7132e002007-08-04 01:51:18 +00005877 declare i64 @llvm.cttz.i64(i64 &lt;src&gt;)
5878 declare i256 @llvm.cttz.i256(i256 &lt;src&gt;)
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005879</pre>
5880
5881<h5>Overview:</h5>
5882
5883<p>
Reid Spencerb4f9a6f2006-01-16 21:12:35 +00005884The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
5885trailing zeros.
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005886</p>
5887
5888<h5>Arguments:</h5>
5889
5890<p>
5891The only argument is the value to be counted. The argument may be of any
Reid Spencer3e628eb92007-01-04 16:43:23 +00005892integer type. The return type must match the argument type.
Chris Lattnerefa20fa2005-05-15 19:39:26 +00005893</p>
5894
5895<h5>Semantics:</h5>
5896
5897<p>
5898The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant) zeros
5899in a variable. If the src == 0 then the result is the size in bits of the type
5900of src. For example, <tt>llvm.cttz(2) = 1</tt>.
5901</p>
5902</div>
5903
Reid Spencer8a5799f2007-04-01 08:27:01 +00005904<!-- _______________________________________________________________________ -->
5905<div class="doc_subsubsection">
Reid Spencerea2945e2007-04-10 02:51:31 +00005906 <a name="int_part_select">'<tt>llvm.part.select.*</tt>' Intrinsic</a>
Reid Spencer8bc7d952007-04-01 19:00:37 +00005907</div>
5908
5909<div class="doc_text">
5910
5911<h5>Syntax:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +00005912<p>This is an overloaded intrinsic. You can use <tt>llvm.part.select</tt>
Dan Gohmanef9462f2008-10-14 16:51:45 +00005913on any integer bit width.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +00005914<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +00005915 declare i17 @llvm.part.select.i17 (i17 %val, i32 %loBit, i32 %hiBit)
5916 declare i29 @llvm.part.select.i29 (i29 %val, i32 %loBit, i32 %hiBit)
Reid Spencer8bc7d952007-04-01 19:00:37 +00005917</pre>
5918
5919<h5>Overview:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +00005920<p>The '<tt>llvm.part.select</tt>' family of intrinsic functions selects a
Reid Spencer8bc7d952007-04-01 19:00:37 +00005921range of bits from an integer value and returns them in the same bit width as
5922the original value.</p>
5923
5924<h5>Arguments:</h5>
5925<p>The first argument, <tt>%val</tt> and the result may be integer types of
5926any bit width but they must have the same bit width. The second and third
Reid Spencer96a5f022007-04-04 02:42:35 +00005927arguments must be <tt>i32</tt> type since they specify only a bit index.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +00005928
5929<h5>Semantics:</h5>
Reid Spencerea2945e2007-04-10 02:51:31 +00005930<p>The operation of the '<tt>llvm.part.select</tt>' intrinsic has two modes
Reid Spencer96a5f022007-04-04 02:42:35 +00005931of operation: forwards and reverse. If <tt>%loBit</tt> is greater than
5932<tt>%hiBits</tt> then the intrinsic operates in reverse mode. Otherwise it
5933operates in forward mode.</p>
5934<p>In forward mode, this intrinsic is the equivalent of shifting <tt>%val</tt>
5935right by <tt>%loBit</tt> bits and then ANDing it with a mask with
Reid Spencer8bc7d952007-04-01 19:00:37 +00005936only the <tt>%hiBit - %loBit</tt> bits set, as follows:</p>
5937<ol>
5938 <li>The <tt>%val</tt> is shifted right (LSHR) by the number of bits specified
5939 by <tt>%loBits</tt>. This normalizes the value to the low order bits.</li>
5940 <li>The <tt>%loBits</tt> value is subtracted from the <tt>%hiBits</tt> value
5941 to determine the number of bits to retain.</li>
5942 <li>A mask of the retained bits is created by shifting a -1 value.</li>
Dan Gohmanef9462f2008-10-14 16:51:45 +00005943 <li>The mask is ANDed with <tt>%val</tt> to produce the result.</li>
Reid Spencer8bc7d952007-04-01 19:00:37 +00005944</ol>
Reid Spencer70845c02007-05-14 16:14:57 +00005945<p>In reverse mode, a similar computation is made except that the bits are
5946returned in the reverse order. So, for example, if <tt>X</tt> has the value
5947<tt>i16 0x0ACF (101011001111)</tt> and we apply
5948<tt>part.select(i16 X, 8, 3)</tt> to it, we get back the value
5949<tt>i16 0x0026 (000000100110)</tt>.</p>
Reid Spencer8bc7d952007-04-01 19:00:37 +00005950</div>
5951
Reid Spencer5bf54c82007-04-11 23:23:49 +00005952<div class="doc_subsubsection">
5953 <a name="int_part_set">'<tt>llvm.part.set.*</tt>' Intrinsic</a>
5954</div>
5955
5956<div class="doc_text">
5957
5958<h5>Syntax:</h5>
5959<p>This is an overloaded intrinsic. You can use <tt>llvm.part.set</tt>
Dan Gohmanef9462f2008-10-14 16:51:45 +00005960on any integer bit width.</p>
Reid Spencer5bf54c82007-04-11 23:23:49 +00005961<pre>
Chandler Carruth7132e002007-08-04 01:51:18 +00005962 declare i17 @llvm.part.set.i17.i9 (i17 %val, i9 %repl, i32 %lo, i32 %hi)
5963 declare i29 @llvm.part.set.i29.i9 (i29 %val, i9 %repl, i32 %lo, i32 %hi)
Reid Spencer5bf54c82007-04-11 23:23:49 +00005964</pre>
5965
5966<h5>Overview:</h5>
5967<p>The '<tt>llvm.part.set</tt>' family of intrinsic functions replaces a range
5968of bits in an integer value with another integer value. It returns the integer
5969with the replaced bits.</p>
5970
5971<h5>Arguments:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005972<p>The first argument, <tt>%val</tt>, and the result may be integer types of
5973any bit width, but they must have the same bit width. <tt>%val</tt> is the value
Reid Spencer5bf54c82007-04-11 23:23:49 +00005974whose bits will be replaced. The second argument, <tt>%repl</tt> may be an
5975integer of any bit width. The third and fourth arguments must be <tt>i32</tt>
5976type since they specify only a bit index.</p>
5977
5978<h5>Semantics:</h5>
5979<p>The operation of the '<tt>llvm.part.set</tt>' intrinsic has two modes
5980of operation: forwards and reverse. If <tt>%lo</tt> is greater than
5981<tt>%hi</tt> then the intrinsic operates in reverse mode. Otherwise it
5982operates in forward mode.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005983
Reid Spencer5bf54c82007-04-11 23:23:49 +00005984<p>For both modes, the <tt>%repl</tt> value is prepared for use by either
5985truncating it down to the size of the replacement area or zero extending it
5986up to that size.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005987
Reid Spencer5bf54c82007-04-11 23:23:49 +00005988<p>In forward mode, the bits between <tt>%lo</tt> and <tt>%hi</tt> (inclusive)
5989are replaced with corresponding bits from <tt>%repl</tt>. That is the 0th bit
5990in <tt>%repl</tt> replaces the <tt>%lo</tt>th bit in <tt>%val</tt> and etc. up
Dan Gohmanef9462f2008-10-14 16:51:45 +00005991to the <tt>%hi</tt>th bit.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005992
Reid Spencer146281c2007-05-14 16:50:20 +00005993<p>In reverse mode, a similar computation is made except that the bits are
5994reversed. That is, the <tt>0</tt>th bit in <tt>%repl</tt> replaces the
Dan Gohmanef9462f2008-10-14 16:51:45 +00005995<tt>%hi</tt> bit in <tt>%val</tt> and etc. down to the <tt>%lo</tt>th bit.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005996
Reid Spencer5bf54c82007-04-11 23:23:49 +00005997<h5>Examples:</h5>
Bill Wendlingf4d70622009-02-08 01:40:31 +00005998
Reid Spencer5bf54c82007-04-11 23:23:49 +00005999<pre>
Reid Spencerc70afc32007-04-12 01:03:03 +00006000 llvm.part.set(0xFFFF, 0, 4, 7) -&gt; 0xFF0F
Reid Spencer146281c2007-05-14 16:50:20 +00006001 llvm.part.set(0xFFFF, 0, 7, 4) -&gt; 0xFF0F
6002 llvm.part.set(0xFFFF, 1, 7, 4) -&gt; 0xFF8F
6003 llvm.part.set(0xFFFF, F, 8, 3) -&gt; 0xFFE7
Reid Spencerc70afc32007-04-12 01:03:03 +00006004 llvm.part.set(0xFFFF, 0, 3, 8) -&gt; 0xFE07
Reid Spencer7972c472007-04-11 23:49:50 +00006005</pre>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006006
6007</div>
6008
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006009<!-- ======================================================================= -->
6010<div class="doc_subsection">
6011 <a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
6012</div>
6013
6014<div class="doc_text">
6015<p>
6016LLVM provides intrinsics for some arithmetic with overflow operations.
6017</p>
6018
6019</div>
6020
Bill Wendlingf4d70622009-02-08 01:40:31 +00006021<!-- _______________________________________________________________________ -->
6022<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006023 <a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006024</div>
6025
6026<div class="doc_text">
6027
6028<h5>Syntax:</h5>
6029
6030<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006031on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006032
6033<pre>
6034 declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
6035 declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6036 declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
6037</pre>
6038
6039<h5>Overview:</h5>
6040
6041<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6042a signed addition of the two arguments, and indicate whether an overflow
6043occurred during the signed summation.</p>
6044
6045<h5>Arguments:</h5>
6046
6047<p>The arguments (%a and %b) and the first element of the result structure may
6048be of integer types of any bit width, but they must have the same bit width. The
6049second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6050and <tt>%b</tt> are the two values that will undergo signed addition.</p>
6051
6052<h5>Semantics:</h5>
6053
6054<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
6055a signed addition of the two variables. They return a structure &mdash; the
6056first element of which is the signed summation, and the second element of which
6057is a bit specifying if the signed summation resulted in an overflow.</p>
6058
6059<h5>Examples:</h5>
6060<pre>
6061 %res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
6062 %sum = extractvalue {i32, i1} %res, 0
6063 %obit = extractvalue {i32, i1} %res, 1
6064 br i1 %obit, label %overflow, label %normal
6065</pre>
6066
6067</div>
6068
6069<!-- _______________________________________________________________________ -->
6070<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006071 <a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006072</div>
6073
6074<div class="doc_text">
6075
6076<h5>Syntax:</h5>
6077
6078<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006079on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006080
6081<pre>
6082 declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
6083 declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6084 declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
6085</pre>
6086
6087<h5>Overview:</h5>
6088
6089<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6090an unsigned addition of the two arguments, and indicate whether a carry occurred
6091during the unsigned summation.</p>
6092
6093<h5>Arguments:</h5>
6094
6095<p>The arguments (%a and %b) and the first element of the result structure may
6096be of integer types of any bit width, but they must have the same bit width. The
6097second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6098and <tt>%b</tt> are the two values that will undergo unsigned addition.</p>
6099
6100<h5>Semantics:</h5>
6101
6102<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
6103an unsigned addition of the two arguments. They return a structure &mdash; the
6104first element of which is the sum, and the second element of which is a bit
6105specifying if the unsigned summation resulted in a carry.</p>
6106
6107<h5>Examples:</h5>
6108<pre>
6109 %res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
6110 %sum = extractvalue {i32, i1} %res, 0
6111 %obit = extractvalue {i32, i1} %res, 1
6112 br i1 %obit, label %carry, label %normal
6113</pre>
6114
6115</div>
6116
6117<!-- _______________________________________________________________________ -->
6118<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006119 <a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006120</div>
6121
6122<div class="doc_text">
6123
6124<h5>Syntax:</h5>
6125
6126<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006127on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006128
6129<pre>
6130 declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
6131 declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6132 declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
6133</pre>
6134
6135<h5>Overview:</h5>
6136
6137<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6138a signed subtraction of the two arguments, and indicate whether an overflow
6139occurred during the signed subtraction.</p>
6140
6141<h5>Arguments:</h5>
6142
6143<p>The arguments (%a and %b) and the first element of the result structure may
6144be of integer types of any bit width, but they must have the same bit width. The
6145second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6146and <tt>%b</tt> are the two values that will undergo signed subtraction.</p>
6147
6148<h5>Semantics:</h5>
6149
6150<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
6151a signed subtraction of the two arguments. They return a structure &mdash; the
6152first element of which is the subtraction, and the second element of which is a bit
6153specifying if the signed subtraction resulted in an overflow.</p>
6154
6155<h5>Examples:</h5>
6156<pre>
6157 %res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
6158 %sum = extractvalue {i32, i1} %res, 0
6159 %obit = extractvalue {i32, i1} %res, 1
6160 br i1 %obit, label %overflow, label %normal
6161</pre>
6162
6163</div>
6164
6165<!-- _______________________________________________________________________ -->
6166<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006167 <a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006168</div>
6169
6170<div class="doc_text">
6171
6172<h5>Syntax:</h5>
6173
6174<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006175on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006176
6177<pre>
6178 declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
6179 declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6180 declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
6181</pre>
6182
6183<h5>Overview:</h5>
6184
6185<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6186an unsigned subtraction of the two arguments, and indicate whether an overflow
6187occurred during the unsigned subtraction.</p>
6188
6189<h5>Arguments:</h5>
6190
6191<p>The arguments (%a and %b) and the first element of the result structure may
6192be of integer types of any bit width, but they must have the same bit width. The
6193second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6194and <tt>%b</tt> are the two values that will undergo unsigned subtraction.</p>
6195
6196<h5>Semantics:</h5>
6197
6198<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
6199an unsigned subtraction of the two arguments. They return a structure &mdash; the
6200first element of which is the subtraction, and the second element of which is a bit
6201specifying if the unsigned subtraction resulted in an overflow.</p>
6202
6203<h5>Examples:</h5>
6204<pre>
6205 %res = call {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
6206 %sum = extractvalue {i32, i1} %res, 0
6207 %obit = extractvalue {i32, i1} %res, 1
6208 br i1 %obit, label %overflow, label %normal
6209</pre>
6210
6211</div>
6212
6213<!-- _______________________________________________________________________ -->
6214<div class="doc_subsubsection">
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006215 <a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006216</div>
6217
6218<div class="doc_text">
6219
6220<h5>Syntax:</h5>
6221
6222<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendlingfd2bd722009-02-08 04:04:40 +00006223on any integer bit width.</p>
Bill Wendlingf4d70622009-02-08 01:40:31 +00006224
6225<pre>
6226 declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
6227 declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6228 declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
6229</pre>
6230
6231<h5>Overview:</h5>
6232
6233<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6234a signed multiplication of the two arguments, and indicate whether an overflow
6235occurred during the signed multiplication.</p>
6236
6237<h5>Arguments:</h5>
6238
6239<p>The arguments (%a and %b) and the first element of the result structure may
6240be of integer types of any bit width, but they must have the same bit width. The
6241second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6242and <tt>%b</tt> are the two values that will undergo signed multiplication.</p>
6243
6244<h5>Semantics:</h5>
6245
6246<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
6247a signed multiplication of the two arguments. They return a structure &mdash;
6248the first element of which is the multiplication, and the second element of
6249which is a bit specifying if the signed multiplication resulted in an
6250overflow.</p>
6251
6252<h5>Examples:</h5>
6253<pre>
6254 %res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
6255 %sum = extractvalue {i32, i1} %res, 0
6256 %obit = extractvalue {i32, i1} %res, 1
6257 br i1 %obit, label %overflow, label %normal
6258</pre>
6259
Reid Spencer5bf54c82007-04-11 23:23:49 +00006260</div>
6261
Bill Wendlingb9a73272009-02-08 23:00:09 +00006262<!-- _______________________________________________________________________ -->
6263<div class="doc_subsubsection">
6264 <a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
6265</div>
6266
6267<div class="doc_text">
6268
6269<h5>Syntax:</h5>
6270
6271<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
6272on any integer bit width.</p>
6273
6274<pre>
6275 declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
6276 declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6277 declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
6278</pre>
6279
6280<h5>Overview:</h5>
6281
6282<p><i><b>Warning:</b> '<tt>llvm.umul.with.overflow</tt>' is badly broken. It is
6283actively being fixed, but it should not currently be used!</i></p>
6284
6285<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6286a unsigned multiplication of the two arguments, and indicate whether an overflow
6287occurred during the unsigned multiplication.</p>
6288
6289<h5>Arguments:</h5>
6290
6291<p>The arguments (%a and %b) and the first element of the result structure may
6292be of integer types of any bit width, but they must have the same bit width. The
6293second element of the result structure must be of type <tt>i1</tt>. <tt>%a</tt>
6294and <tt>%b</tt> are the two values that will undergo unsigned
6295multiplication.</p>
6296
6297<h5>Semantics:</h5>
6298
6299<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
6300an unsigned multiplication of the two arguments. They return a structure &mdash;
6301the first element of which is the multiplication, and the second element of
6302which is a bit specifying if the unsigned multiplication resulted in an
6303overflow.</p>
6304
6305<h5>Examples:</h5>
6306<pre>
6307 %res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
6308 %sum = extractvalue {i32, i1} %res, 0
6309 %obit = extractvalue {i32, i1} %res, 1
6310 br i1 %obit, label %overflow, label %normal
6311</pre>
6312
6313</div>
6314
Chris Lattner941515c2004-01-06 05:31:32 +00006315<!-- ======================================================================= -->
6316<div class="doc_subsection">
6317 <a name="int_debugger">Debugger Intrinsics</a>
6318</div>
6319
6320<div class="doc_text">
6321<p>
6322The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt> prefix),
6323are described in the <a
6324href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source Level
6325Debugging</a> document.
6326</p>
6327</div>
6328
6329
Jim Laskey2211f492007-03-14 19:31:19 +00006330<!-- ======================================================================= -->
6331<div class="doc_subsection">
6332 <a name="int_eh">Exception Handling Intrinsics</a>
6333</div>
6334
6335<div class="doc_text">
6336<p> The LLVM exception handling intrinsics (which all start with
6337<tt>llvm.eh.</tt> prefix), are described in the <a
6338href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
6339Handling</a> document. </p>
6340</div>
6341
Tanya Lattnercb1b9602007-06-15 20:50:54 +00006342<!-- ======================================================================= -->
6343<div class="doc_subsection">
Duncan Sands86e01192007-09-11 14:10:23 +00006344 <a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands644f9172007-07-27 12:58:54 +00006345</div>
6346
6347<div class="doc_text">
6348<p>
Duncan Sands86e01192007-09-11 14:10:23 +00006349 This intrinsic makes it possible to excise one parameter, marked with
Duncan Sands644f9172007-07-27 12:58:54 +00006350 the <tt>nest</tt> attribute, from a function. The result is a callable
6351 function pointer lacking the nest parameter - the caller does not need
6352 to provide a value for it. Instead, the value to use is stored in
6353 advance in a "trampoline", a block of memory usually allocated
6354 on the stack, which also contains code to splice the nest value into the
6355 argument list. This is used to implement the GCC nested function address
6356 extension.
6357</p>
6358<p>
6359 For example, if the function is
6360 <tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
Bill Wendling252570f2007-09-22 09:23:55 +00006361 pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as follows:</p>
Duncan Sands644f9172007-07-27 12:58:54 +00006362<pre>
Duncan Sands86e01192007-09-11 14:10:23 +00006363 %tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
6364 %tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
6365 %p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8*), i8* %nval )
6366 %fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands644f9172007-07-27 12:58:54 +00006367</pre>
Bill Wendling252570f2007-09-22 09:23:55 +00006368 <p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
6369 to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
Duncan Sands644f9172007-07-27 12:58:54 +00006370</div>
6371
6372<!-- _______________________________________________________________________ -->
6373<div class="doc_subsubsection">
6374 <a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
6375</div>
6376<div class="doc_text">
6377<h5>Syntax:</h5>
6378<pre>
Duncan Sands86e01192007-09-11 14:10:23 +00006379declare i8* @llvm.init.trampoline(i8* &lt;tramp&gt;, i8* &lt;func&gt;, i8* &lt;nval&gt;)
Duncan Sands644f9172007-07-27 12:58:54 +00006380</pre>
6381<h5>Overview:</h5>
6382<p>
Duncan Sands86e01192007-09-11 14:10:23 +00006383 This fills the memory pointed to by <tt>tramp</tt> with code
6384 and returns a function pointer suitable for executing it.
Duncan Sands644f9172007-07-27 12:58:54 +00006385</p>
6386<h5>Arguments:</h5>
6387<p>
6388 The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
6389 pointers. The <tt>tramp</tt> argument must point to a sufficiently large
6390 and sufficiently aligned block of memory; this memory is written to by the
Duncan Sandsf2bcd372007-08-22 23:39:54 +00006391 intrinsic. Note that the size and the alignment are target-specific - LLVM
6392 currently provides no portable way of determining them, so a front-end that
6393 generates this intrinsic needs to have some target-specific knowledge.
6394 The <tt>func</tt> argument must hold a function bitcast to an <tt>i8*</tt>.
Duncan Sands644f9172007-07-27 12:58:54 +00006395</p>
6396<h5>Semantics:</h5>
6397<p>
6398 The block of memory pointed to by <tt>tramp</tt> is filled with target
Duncan Sands86e01192007-09-11 14:10:23 +00006399 dependent code, turning it into a function. A pointer to this function is
6400 returned, but needs to be bitcast to an
Duncan Sands644f9172007-07-27 12:58:54 +00006401 <a href="#int_trampoline">appropriate function pointer type</a>
Duncan Sands86e01192007-09-11 14:10:23 +00006402 before being called. The new function's signature is the same as that of
6403 <tt>func</tt> with any arguments marked with the <tt>nest</tt> attribute
6404 removed. At most one such <tt>nest</tt> argument is allowed, and it must be
6405 of pointer type. Calling the new function is equivalent to calling
6406 <tt>func</tt> with the same argument list, but with <tt>nval</tt> used for the
6407 missing <tt>nest</tt> argument. If, after calling
6408 <tt>llvm.init.trampoline</tt>, the memory pointed to by <tt>tramp</tt> is
6409 modified, then the effect of any later call to the returned function pointer is
6410 undefined.
Duncan Sands644f9172007-07-27 12:58:54 +00006411</p>
6412</div>
6413
6414<!-- ======================================================================= -->
6415<div class="doc_subsection">
Andrew Lenharth9b254ee2008-02-16 01:24:58 +00006416 <a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
6417</div>
6418
6419<div class="doc_text">
6420<p>
6421 These intrinsic functions expand the "universal IR" of LLVM to represent
6422 hardware constructs for atomic operations and memory synchronization. This
6423 provides an interface to the hardware, not an interface to the programmer. It
Chris Lattner67c37d12008-08-05 18:29:16 +00006424 is aimed at a low enough level to allow any programming models or APIs
6425 (Application Programming Interfaces) which
Andrew Lenharth9b254ee2008-02-16 01:24:58 +00006426 need atomic behaviors to map cleanly onto it. It is also modeled primarily on
6427 hardware behavior. Just as hardware provides a "universal IR" for source
6428 languages, it also provides a starting point for developing a "universal"
6429 atomic operation and synchronization IR.
6430</p>
6431<p>
6432 These do <em>not</em> form an API such as high-level threading libraries,
6433 software transaction memory systems, atomic primitives, and intrinsic
6434 functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
6435 application libraries. The hardware interface provided by LLVM should allow
6436 a clean implementation of all of these APIs and parallel programming models.
6437 No one model or paradigm should be selected above others unless the hardware
6438 itself ubiquitously does so.
6439
6440</p>
6441</div>
6442
6443<!-- _______________________________________________________________________ -->
6444<div class="doc_subsubsection">
6445 <a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
6446</div>
6447<div class="doc_text">
6448<h5>Syntax:</h5>
6449<pre>
6450declare void @llvm.memory.barrier( i1 &lt;ll&gt;, i1 &lt;ls&gt;, i1 &lt;sl&gt;, i1 &lt;ss&gt;,
6451i1 &lt;device&gt; )
6452
6453</pre>
6454<h5>Overview:</h5>
6455<p>
6456 The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
6457 specific pairs of memory access types.
6458</p>
6459<h5>Arguments:</h5>
6460<p>
6461 The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
6462 The first four arguments enables a specific barrier as listed below. The fith
6463 argument specifies that the barrier applies to io or device or uncached memory.
6464
6465</p>
6466 <ul>
6467 <li><tt>ll</tt>: load-load barrier</li>
6468 <li><tt>ls</tt>: load-store barrier</li>
6469 <li><tt>sl</tt>: store-load barrier</li>
6470 <li><tt>ss</tt>: store-store barrier</li>
Dan Gohmanef9462f2008-10-14 16:51:45 +00006471 <li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +00006472 </ul>
6473<h5>Semantics:</h5>
6474<p>
6475 This intrinsic causes the system to enforce some ordering constraints upon
6476 the loads and stores of the program. This barrier does not indicate
6477 <em>when</em> any events will occur, it only enforces an <em>order</em> in
6478 which they occur. For any of the specified pairs of load and store operations
6479 (f.ex. load-load, or store-load), all of the first operations preceding the
6480 barrier will complete before any of the second operations succeeding the
6481 barrier begin. Specifically the semantics for each pairing is as follows:
6482</p>
6483 <ul>
6484 <li><tt>ll</tt>: All loads before the barrier must complete before any load
6485 after the barrier begins.</li>
6486
6487 <li><tt>ls</tt>: All loads before the barrier must complete before any
6488 store after the barrier begins.</li>
6489 <li><tt>ss</tt>: All stores before the barrier must complete before any
6490 store after the barrier begins.</li>
6491 <li><tt>sl</tt>: All stores before the barrier must complete before any
6492 load after the barrier begins.</li>
6493 </ul>
6494<p>
6495 These semantics are applied with a logical "and" behavior when more than one
6496 is enabled in a single memory barrier intrinsic.
6497</p>
6498<p>
6499 Backends may implement stronger barriers than those requested when they do not
6500 support as fine grained a barrier as requested. Some architectures do not
6501 need all types of barriers and on such architectures, these become noops.
6502</p>
6503<h5>Example:</h5>
6504<pre>
6505%ptr = malloc i32
6506 store i32 4, %ptr
6507
6508%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
6509 call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
6510 <i>; guarantee the above finishes</i>
6511 store i32 8, %ptr <i>; before this begins</i>
6512</pre>
6513</div>
6514
Andrew Lenharth95528942008-02-21 06:45:13 +00006515<!-- _______________________________________________________________________ -->
6516<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +00006517 <a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +00006518</div>
6519<div class="doc_text">
6520<h5>Syntax:</h5>
6521<p>
Mon P Wang2c839d42008-07-30 04:36:53 +00006522 This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
6523 any integer bit width and for different address spaces. Not all targets
6524 support all bit widths however.</p>
Andrew Lenharth95528942008-02-21 06:45:13 +00006525
6526<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006527declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;cmp&gt;, i8 &lt;val&gt; )
6528declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;cmp&gt;, i16 &lt;val&gt; )
6529declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;cmp&gt;, i32 &lt;val&gt; )
6530declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;cmp&gt;, i64 &lt;val&gt; )
Andrew Lenharth95528942008-02-21 06:45:13 +00006531
6532</pre>
6533<h5>Overview:</h5>
6534<p>
6535 This loads a value in memory and compares it to a given value. If they are
6536 equal, it stores a new value into the memory.
6537</p>
6538<h5>Arguments:</h5>
6539<p>
Mon P Wang6a490372008-06-25 08:15:39 +00006540 The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result as
Andrew Lenharth95528942008-02-21 06:45:13 +00006541 well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
6542 same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
6543 this integer type. While any bit width integer may be used, targets may only
6544 lower representations they support in hardware.
6545
6546</p>
6547<h5>Semantics:</h5>
6548<p>
6549 This entire intrinsic must be executed atomically. It first loads the value
6550 in memory pointed to by <tt>ptr</tt> and compares it with the value
6551 <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the memory. The
6552 loaded value is yielded in all cases. This provides the equivalent of an
6553 atomic compare-and-swap operation within the SSA framework.
6554</p>
6555<h5>Examples:</h5>
6556
6557<pre>
6558%ptr = malloc i32
6559 store i32 4, %ptr
6560
6561%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +00006562%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006563 <i>; yields {i32}:result1 = 4</i>
6564%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6565%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6566
6567%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +00006568%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006569 <i>; yields {i32}:result2 = 8</i>
6570%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
6571
6572%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
6573</pre>
6574</div>
6575
6576<!-- _______________________________________________________________________ -->
6577<div class="doc_subsubsection">
6578 <a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
6579</div>
6580<div class="doc_text">
6581<h5>Syntax:</h5>
6582
6583<p>
6584 This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
6585 integer bit width. Not all targets support all bit widths however.</p>
6586<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006587declare i8 @llvm.atomic.swap.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;val&gt; )
6588declare i16 @llvm.atomic.swap.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;val&gt; )
6589declare i32 @llvm.atomic.swap.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;val&gt; )
6590declare i64 @llvm.atomic.swap.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;val&gt; )
Andrew Lenharth95528942008-02-21 06:45:13 +00006591
6592</pre>
6593<h5>Overview:</h5>
6594<p>
6595 This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
6596 the value from memory. It then stores the value in <tt>val</tt> in the memory
6597 at <tt>ptr</tt>.
6598</p>
6599<h5>Arguments:</h5>
6600
6601<p>
Mon P Wang6a490372008-06-25 08:15:39 +00006602 The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both the
Andrew Lenharth95528942008-02-21 06:45:13 +00006603 <tt>val</tt> argument and the result must be integers of the same bit width.
6604 The first argument, <tt>ptr</tt>, must be a pointer to a value of this
6605 integer type. The targets may only lower integer representations they
6606 support.
6607</p>
6608<h5>Semantics:</h5>
6609<p>
6610 This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
6611 stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
6612 equivalent of an atomic swap operation within the SSA framework.
6613
6614</p>
6615<h5>Examples:</h5>
6616<pre>
6617%ptr = malloc i32
6618 store i32 4, %ptr
6619
6620%val1 = add i32 4, 4
Mon P Wang2c839d42008-07-30 04:36:53 +00006621%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006622 <i>; yields {i32}:result1 = 4</i>
6623%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
6624%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
6625
6626%val2 = add i32 1, 1
Mon P Wang2c839d42008-07-30 04:36:53 +00006627%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006628 <i>; yields {i32}:result2 = 8</i>
6629
6630%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
6631%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
6632</pre>
6633</div>
6634
6635<!-- _______________________________________________________________________ -->
6636<div class="doc_subsubsection">
Mon P Wang6a490372008-06-25 08:15:39 +00006637 <a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth95528942008-02-21 06:45:13 +00006638
6639</div>
6640<div class="doc_text">
6641<h5>Syntax:</h5>
6642<p>
Mon P Wang6a490372008-06-25 08:15:39 +00006643 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on any
Andrew Lenharth95528942008-02-21 06:45:13 +00006644 integer bit width. Not all targets support all bit widths however.</p>
6645<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006646declare i8 @llvm.atomic.load.add.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6647declare i16 @llvm.atomic.load.add.i16..p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6648declare i32 @llvm.atomic.load.add.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6649declare i64 @llvm.atomic.load.add.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Andrew Lenharth95528942008-02-21 06:45:13 +00006650
6651</pre>
6652<h5>Overview:</h5>
6653<p>
6654 This intrinsic adds <tt>delta</tt> to the value stored in memory at
6655 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6656</p>
6657<h5>Arguments:</h5>
6658<p>
6659
6660 The intrinsic takes two arguments, the first a pointer to an integer value
6661 and the second an integer value. The result is also an integer value. These
6662 integer types can have any bit width, but they must all have the same bit
6663 width. The targets may only lower integer representations they support.
6664</p>
6665<h5>Semantics:</h5>
6666<p>
6667 This intrinsic does a series of operations atomically. It first loads the
6668 value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
6669 to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6670</p>
6671
6672<h5>Examples:</h5>
6673<pre>
6674%ptr = malloc i32
6675 store i32 4, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +00006676%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006677 <i>; yields {i32}:result1 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006678%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006679 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006680%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth95528942008-02-21 06:45:13 +00006681 <i>; yields {i32}:result3 = 10</i>
Mon P Wang6a490372008-06-25 08:15:39 +00006682%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth95528942008-02-21 06:45:13 +00006683</pre>
6684</div>
6685
Mon P Wang6a490372008-06-25 08:15:39 +00006686<!-- _______________________________________________________________________ -->
6687<div class="doc_subsubsection">
6688 <a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
6689
6690</div>
6691<div class="doc_text">
6692<h5>Syntax:</h5>
6693<p>
6694 This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
Mon P Wang2c839d42008-07-30 04:36:53 +00006695 any integer bit width and for different address spaces. Not all targets
6696 support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +00006697<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006698declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6699declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6700declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6701declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006702
6703</pre>
6704<h5>Overview:</h5>
6705<p>
6706 This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
6707 <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.
6708</p>
6709<h5>Arguments:</h5>
6710<p>
6711
6712 The intrinsic takes two arguments, the first a pointer to an integer value
6713 and the second an integer value. The result is also an integer value. These
6714 integer types can have any bit width, but they must all have the same bit
6715 width. The targets may only lower integer representations they support.
6716</p>
6717<h5>Semantics:</h5>
6718<p>
6719 This intrinsic does a series of operations atomically. It first loads the
6720 value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
6721 result to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.
6722</p>
6723
6724<h5>Examples:</h5>
6725<pre>
6726%ptr = malloc i32
6727 store i32 8, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +00006728%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang6a490372008-06-25 08:15:39 +00006729 <i>; yields {i32}:result1 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006730%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang6a490372008-06-25 08:15:39 +00006731 <i>; yields {i32}:result2 = 4</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006732%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang6a490372008-06-25 08:15:39 +00006733 <i>; yields {i32}:result3 = 2</i>
6734%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
6735</pre>
6736</div>
6737
6738<!-- _______________________________________________________________________ -->
6739<div class="doc_subsubsection">
6740 <a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
6741 <a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
6742 <a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
6743 <a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
6744
6745</div>
6746<div class="doc_text">
6747<h5>Syntax:</h5>
6748<p>
6749 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_and</tt>,
6750 <tt>llvm.atomic.load_nand</tt>, <tt>llvm.atomic.load_or</tt>, and
Mon P Wang2c839d42008-07-30 04:36:53 +00006751 <tt>llvm.atomic.load_xor</tt> on any integer bit width and for different
6752 address spaces. Not all targets support all bit widths however.</p>
Mon P Wang6a490372008-06-25 08:15:39 +00006753<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006754declare i8 @llvm.atomic.load.and.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6755declare i16 @llvm.atomic.load.and.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6756declare i32 @llvm.atomic.load.and.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6757declare i64 @llvm.atomic.load.and.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006758
6759</pre>
6760
6761<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006762declare i8 @llvm.atomic.load.or.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6763declare i16 @llvm.atomic.load.or.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6764declare i32 @llvm.atomic.load.or.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6765declare i64 @llvm.atomic.load.or.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006766
6767</pre>
6768
6769<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006770declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6771declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6772declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6773declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006774
6775</pre>
6776
6777<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006778declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6779declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6780declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6781declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006782
6783</pre>
6784<h5>Overview:</h5>
6785<p>
6786 These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
6787 the value stored in memory at <tt>ptr</tt>. It yields the original value
6788 at <tt>ptr</tt>.
6789</p>
6790<h5>Arguments:</h5>
6791<p>
6792
6793 These intrinsics take two arguments, the first a pointer to an integer value
6794 and the second an integer value. The result is also an integer value. These
6795 integer types can have any bit width, but they must all have the same bit
6796 width. The targets may only lower integer representations they support.
6797</p>
6798<h5>Semantics:</h5>
6799<p>
6800 These intrinsics does a series of operations atomically. They first load the
6801 value stored at <tt>ptr</tt>. They then do the bitwise operation
6802 <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the original
6803 value stored at <tt>ptr</tt>.
6804</p>
6805
6806<h5>Examples:</h5>
6807<pre>
6808%ptr = malloc i32
6809 store i32 0x0F0F, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +00006810%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +00006811 <i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006812%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang6a490372008-06-25 08:15:39 +00006813 <i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006814%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +00006815 <i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006816%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang6a490372008-06-25 08:15:39 +00006817 <i>; yields {i32}:result3 = FF</i>
6818%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
6819</pre>
6820</div>
6821
6822
6823<!-- _______________________________________________________________________ -->
6824<div class="doc_subsubsection">
6825 <a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
6826 <a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
6827 <a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
6828 <a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
6829
6830</div>
6831<div class="doc_text">
6832<h5>Syntax:</h5>
6833<p>
6834 These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
6835 <tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
Mon P Wang2c839d42008-07-30 04:36:53 +00006836 <tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
6837 address spaces. Not all targets
Mon P Wang6a490372008-06-25 08:15:39 +00006838 support all bit widths however.</p>
6839<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006840declare i8 @llvm.atomic.load.max.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6841declare i16 @llvm.atomic.load.max.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6842declare i32 @llvm.atomic.load.max.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6843declare i64 @llvm.atomic.load.max.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006844
6845</pre>
6846
6847<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006848declare i8 @llvm.atomic.load.min.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6849declare i16 @llvm.atomic.load.min.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6850declare i32 @llvm.atomic.load.min.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6851declare i64 @llvm.atomic.load.min.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006852
6853</pre>
6854
6855<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006856declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6857declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6858declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6859declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006860
6861</pre>
6862
6863<pre>
Mon P Wang2c839d42008-07-30 04:36:53 +00006864declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* &lt;ptr&gt;, i8 &lt;delta&gt; )
6865declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* &lt;ptr&gt;, i16 &lt;delta&gt; )
6866declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* &lt;ptr&gt;, i32 &lt;delta&gt; )
6867declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* &lt;ptr&gt;, i64 &lt;delta&gt; )
Mon P Wang6a490372008-06-25 08:15:39 +00006868
6869</pre>
6870<h5>Overview:</h5>
6871<p>
6872 These intrinsics takes the signed or unsigned minimum or maximum of
6873 <tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
6874 original value at <tt>ptr</tt>.
6875</p>
6876<h5>Arguments:</h5>
6877<p>
6878
6879 These intrinsics take two arguments, the first a pointer to an integer value
6880 and the second an integer value. The result is also an integer value. These
6881 integer types can have any bit width, but they must all have the same bit
6882 width. The targets may only lower integer representations they support.
6883</p>
6884<h5>Semantics:</h5>
6885<p>
6886 These intrinsics does a series of operations atomically. They first load the
6887 value stored at <tt>ptr</tt>. They then do the signed or unsigned min or max
6888 <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They yield
6889 the original value stored at <tt>ptr</tt>.
6890</p>
6891
6892<h5>Examples:</h5>
6893<pre>
6894%ptr = malloc i32
6895 store i32 7, %ptr
Mon P Wang2c839d42008-07-30 04:36:53 +00006896%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang6a490372008-06-25 08:15:39 +00006897 <i>; yields {i32}:result0 = 7</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006898%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang6a490372008-06-25 08:15:39 +00006899 <i>; yields {i32}:result1 = -2</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006900%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang6a490372008-06-25 08:15:39 +00006901 <i>; yields {i32}:result2 = 8</i>
Mon P Wang2c839d42008-07-30 04:36:53 +00006902%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang6a490372008-06-25 08:15:39 +00006903 <i>; yields {i32}:result3 = 8</i>
6904%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
6905</pre>
6906</div>
Andrew Lenharth9b254ee2008-02-16 01:24:58 +00006907
6908<!-- ======================================================================= -->
6909<div class="doc_subsection">
Tanya Lattnercb1b9602007-06-15 20:50:54 +00006910 <a name="int_general">General Intrinsics</a>
6911</div>
6912
6913<div class="doc_text">
6914<p> This class of intrinsics is designed to be generic and has
6915no specific purpose. </p>
6916</div>
6917
6918<!-- _______________________________________________________________________ -->
6919<div class="doc_subsubsection">
6920 <a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
6921</div>
6922
6923<div class="doc_text">
6924
6925<h5>Syntax:</h5>
6926<pre>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +00006927 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 +00006928</pre>
6929
6930<h5>Overview:</h5>
6931
6932<p>
6933The '<tt>llvm.var.annotation</tt>' intrinsic
6934</p>
6935
6936<h5>Arguments:</h5>
6937
6938<p>
Tanya Lattnerbed1d4d2007-06-18 23:42:37 +00006939The first argument is a pointer to a value, the second is a pointer to a
6940global string, the third is a pointer to a global string which is the source
6941file name, and the last argument is the line number.
Tanya Lattnercb1b9602007-06-15 20:50:54 +00006942</p>
6943
6944<h5>Semantics:</h5>
6945
6946<p>
Anton Korobeynikov06cbb652008-01-15 22:31:34 +00006947This intrinsic allows annotation of local variables with arbitrary strings.
Tanya Lattnercb1b9602007-06-15 20:50:54 +00006948This can be useful for special purpose optimizations that want to look for these
Anton Korobeynikov06cbb652008-01-15 22:31:34 +00006949annotations. These have no other defined use, they are ignored by code
6950generation and optimization.
6951</p>
Tanya Lattnercb1b9602007-06-15 20:50:54 +00006952</div>
6953
Tanya Lattner293c0372007-09-21 22:59:12 +00006954<!-- _______________________________________________________________________ -->
6955<div class="doc_subsubsection">
Tanya Lattner0186a652007-09-21 23:57:59 +00006956 <a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner293c0372007-09-21 22:59:12 +00006957</div>
6958
6959<div class="doc_text">
6960
6961<h5>Syntax:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +00006962<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
6963any integer bit width.
6964</p>
Tanya Lattner293c0372007-09-21 22:59:12 +00006965<pre>
Tanya Lattnercf3e26f2007-09-22 00:03:01 +00006966 declare i8 @llvm.annotation.i8(i8 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6967 declare i16 @llvm.annotation.i16(i16 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6968 declare i32 @llvm.annotation.i32(i32 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6969 declare i64 @llvm.annotation.i64(i64 &lt;val&gt;, i8* &lt;str&gt;, i8* &lt;str&gt;, i32 &lt;int&gt; )
6970 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 +00006971</pre>
6972
6973<h5>Overview:</h5>
Tanya Lattner23dbd572007-09-21 23:56:27 +00006974
6975<p>
6976The '<tt>llvm.annotation</tt>' intrinsic.
Tanya Lattner293c0372007-09-21 22:59:12 +00006977</p>
6978
6979<h5>Arguments:</h5>
6980
6981<p>
6982The first argument is an integer value (result of some expression),
6983the second is a pointer to a global string, the third is a pointer to a global
6984string which is the source file name, and the last argument is the line number.
Tanya Lattner23dbd572007-09-21 23:56:27 +00006985It returns the value of the first argument.
Tanya Lattner293c0372007-09-21 22:59:12 +00006986</p>
6987
6988<h5>Semantics:</h5>
6989
6990<p>
6991This intrinsic allows annotations to be put on arbitrary expressions
6992with arbitrary strings. This can be useful for special purpose optimizations
6993that want to look for these annotations. These have no other defined use, they
6994are ignored by code generation and optimization.
Dan Gohmanef9462f2008-10-14 16:51:45 +00006995</p>
Tanya Lattner293c0372007-09-21 22:59:12 +00006996</div>
Jim Laskey2211f492007-03-14 19:31:19 +00006997
Anton Korobeynikov06cbb652008-01-15 22:31:34 +00006998<!-- _______________________________________________________________________ -->
6999<div class="doc_subsubsection">
7000 <a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
7001</div>
7002
7003<div class="doc_text">
7004
7005<h5>Syntax:</h5>
7006<pre>
7007 declare void @llvm.trap()
7008</pre>
7009
7010<h5>Overview:</h5>
7011
7012<p>
7013The '<tt>llvm.trap</tt>' intrinsic
7014</p>
7015
7016<h5>Arguments:</h5>
7017
7018<p>
7019None
7020</p>
7021
7022<h5>Semantics:</h5>
7023
7024<p>
7025This intrinsics is lowered to the target dependent trap instruction. If the
7026target does not have a trap instruction, this intrinsic will be lowered to the
7027call of the abort() function.
7028</p>
7029</div>
7030
Bill Wendling14313312008-11-19 05:56:17 +00007031<!-- _______________________________________________________________________ -->
7032<div class="doc_subsubsection">
Misha Brukman50de2b22008-11-22 23:55:29 +00007033 <a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling14313312008-11-19 05:56:17 +00007034</div>
7035<div class="doc_text">
7036<h5>Syntax:</h5>
7037<pre>
7038declare void @llvm.stackprotector( i8* &lt;guard&gt;, i8** &lt;slot&gt; )
7039
7040</pre>
7041<h5>Overview:</h5>
7042<p>
7043 The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and stores
7044 it onto the stack at <tt>slot</tt>. The stack slot is adjusted to ensure that
7045 it is placed on the stack before local variables.
7046</p>
7047<h5>Arguments:</h5>
7048<p>
7049 The <tt>llvm.stackprotector</tt> intrinsic requires two pointer arguments. The
7050 first argument is the value loaded from the stack guard
7051 <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt> that
7052 has enough space to hold the value of the guard.
7053</p>
7054<h5>Semantics:</h5>
7055<p>
7056 This intrinsic causes the prologue/epilogue inserter to force the position of
7057 the <tt>AllocaInst</tt> stack slot to be before local variables on the
7058 stack. This is to ensure that if a local variable on the stack is overwritten,
7059 it will destroy the value of the guard. When the function exits, the guard on
7060 the stack is checked against the original guard. If they're different, then
7061 the program aborts by calling the <tt>__stack_chk_fail()</tt> function.
7062</p>
7063</div>
7064
Chris Lattner2f7c9632001-06-06 20:29:01 +00007065<!-- *********************************************************************** -->
Chris Lattner2f7c9632001-06-06 20:29:01 +00007066<hr>
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Misha Brukmanc501f552004-03-01 17:47:27 +00007072
7073 <a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
Reid Spencerca058542006-03-14 05:39:39 +00007074 <a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
Misha Brukmanc501f552004-03-01 17:47:27 +00007075 Last modified: $Date$
7076</address>
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7079</html>