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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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				13	<body>
				14
				15	<div class="doc_title"> LLVM Language Reference Manual </div>
				16	<ol>
				17	<li><a href="#abstract">Abstract</a></li>
				18	<li><a href="#introduction">Introduction</a></li>
				19	<li><a href="#identifiers">Identifiers</a></li>
				20	<li><a href="#highlevel">High Level Structure</a>
				21	<ol>
				22	<li><a href="#modulestructure">Module Structure</a></li>
Bill Wendling	41a0785	2009-07-20 01:03:30 +0000	[diff] [blame]	23	<li><a href="#linkage">Linkage Types</a>
				24	<ol>
Bill Wendling	e275324	2009-07-20 02:41:50 +0000	[diff] [blame]	25	<li><a href="#linkage_private">'<tt>private</tt>' Linkage</a></li>
				26	<li><a href="#linkage_linker_private">'<tt>linker_private</tt>' Linkage</a></li>
				27	<li><a href="#linkage_internal">'<tt>internal</tt>' Linkage</a></li>
				28	<li><a href="#linkage_available_externally">'<tt>available_externally</tt>' Linkage</a></li>
				29	<li><a href="#linkage_linkonce">'<tt>linkonce</tt>' Linkage</a></li>
				30	<li><a href="#linkage_common">'<tt>common</tt>' Linkage</a></li>
				31	<li><a href="#linkage_weak">'<tt>weak</tt>' Linkage</a></li>
				32	<li><a href="#linkage_appending">'<tt>appending</tt>' Linkage</a></li>
				33	<li><a href="#linkage_externweak">'<tt>extern_weak</tt>' Linkage</a></li>
				34	<li><a href="#linkage_linkonce">'<tt>linkonce_odr</tt>' Linkage</a></li>
				35	<li><a href="#linkage_weak">'<tt>weak_odr</tt>' Linkage</a></li>
				36	<li><a href="#linkage_external">'<tt>externally visible</tt>' Linkage</a></li>
				37	<li><a href="#linkage_dllimport">'<tt>dllimport</tt>' Linkage</a></li>
				38	<li><a href="#linkage_dllexport">'<tt>dllexport</tt>' Linkage</a></li>
Bill Wendling	41a0785	2009-07-20 01:03:30 +0000	[diff] [blame]	39	</ol>
				40	</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	41	<li><a href="#callingconv">Calling Conventions</a></li>
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	42	<li><a href="#namedtypes">Named Types</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	43	<li><a href="#globalvars">Global Variables</a></li>
				44	<li><a href="#functionstructure">Functions</a></li>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	45	<li><a href="#aliasstructure">Aliases</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	46	<li><a href="#paramattrs">Parameter Attributes</a></li>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	47	<li><a href="#fnattrs">Function Attributes</a></li>
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	48	<li><a href="#gc">Garbage Collector Names</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	49	<li><a href="#moduleasm">Module-Level Inline Assembly</a></li>
				50	<li><a href="#datalayout">Data Layout</a></li>
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	51	<li><a href="#pointeraliasing">Pointer Aliasing Rules</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	52	</ol>
				53	</li>
				54	<li><a href="#typesystem">Type System</a>
				55	<ol>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	56	<li><a href="#t_classifications">Type Classifications</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	57	<li><a href="#t_primitive">Primitive Types</a>
				58	<ol>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	59	<li><a href="#t_floating">Floating Point Types</a></li>
				60	<li><a href="#t_void">Void Type</a></li>
				61	<li><a href="#t_label">Label Type</a></li>
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	62	<li><a href="#t_metadata">Metadata Type</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	63	</ol>
				64	</li>
				65	<li><a href="#t_derived">Derived Types</a>
				66	<ol>
Chris Lattner	251ab81	2007-12-18 06:18:21 +0000	[diff] [blame]	67	<li><a href="#t_integer">Integer Type</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	68	<li><a href="#t_array">Array Type</a></li>
				69	<li><a href="#t_function">Function Type</a></li>
				70	<li><a href="#t_pointer">Pointer Type</a></li>
				71	<li><a href="#t_struct">Structure Type</a></li>
				72	<li><a href="#t_pstruct">Packed Structure Type</a></li>
				73	<li><a href="#t_vector">Vector Type</a></li>
				74	<li><a href="#t_opaque">Opaque Type</a></li>
				75	</ol>
				76	</li>
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	77	<li><a href="#t_uprefs">Type Up-references</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	78	</ol>
				79	</li>
				80	<li><a href="#constants">Constants</a>
				81	<ol>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	82	<li><a href="#simpleconstants">Simple Constants</a></li>
Chris Lattner	9706385	2009-02-28 18:32:25 +0000	[diff] [blame]	83	<li><a href="#complexconstants">Complex Constants</a></li>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	84	<li><a href="#globalconstants">Global Variable and Function Addresses</a></li>
				85	<li><a href="#undefvalues">Undefined Values</a></li>
				86	<li><a href="#constantexprs">Constant Expressions</a></li>
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	87	<li><a href="#metadata">Embedded Metadata</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	88	</ol>
				89	</li>
				90	<li><a href="#othervalues">Other Values</a>
				91	<ol>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	92	<li><a href="#inlineasm">Inline Assembler Expressions</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	93	</ol>
				94	</li>
Chris Lattner	75c24e0	2009-07-20 05:55:19 +0000	[diff] [blame]	95	<li><a href="#intrinsic_globals">Intrinsic Global Variables</a>
				96	<ol>
				97	<li><a href="#intg_used">The '<tt>llvm.used</tt>' Global Variable</a></li>
Chris Lattner	1e0e0d1	2009-07-20 06:14:25 +0000	[diff] [blame]	98	<li><a href="#intg_compiler_used">The '<tt>llvm.compiler.used</tt>'
				99	Global Variable</a></li>
Chris Lattner	75c24e0	2009-07-20 05:55:19 +0000	[diff] [blame]	100	<li><a href="#intg_global_ctors">The '<tt>llvm.global_ctors</tt>'
				101	Global Variable</a></li>
				102	<li><a href="#intg_global_dtors">The '<tt>llvm.global_dtors</tt>'
				103	Global Variable</a></li>
				104	</ol>
				105	</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	106	<li><a href="#instref">Instruction Reference</a>
				107	<ol>
				108	<li><a href="#terminators">Terminator Instructions</a>
				109	<ol>
				110	<li><a href="#i_ret">'<tt>ret</tt>' Instruction</a></li>
				111	<li><a href="#i_br">'<tt>br</tt>' Instruction</a></li>
				112	<li><a href="#i_switch">'<tt>switch</tt>' Instruction</a></li>
				113	<li><a href="#i_invoke">'<tt>invoke</tt>' Instruction</a></li>
				114	<li><a href="#i_unwind">'<tt>unwind</tt>' Instruction</a></li>
				115	<li><a href="#i_unreachable">'<tt>unreachable</tt>' Instruction</a></li>
				116	</ol>
				117	</li>
				118	<li><a href="#binaryops">Binary Operations</a>
				119	<ol>
				120	<li><a href="#i_add">'<tt>add</tt>' Instruction</a></li>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	121	<li><a href="#i_fadd">'<tt>fadd</tt>' Instruction</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	122	<li><a href="#i_sub">'<tt>sub</tt>' Instruction</a></li>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	123	<li><a href="#i_fsub">'<tt>fsub</tt>' Instruction</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	124	<li><a href="#i_mul">'<tt>mul</tt>' Instruction</a></li>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	125	<li><a href="#i_fmul">'<tt>fmul</tt>' Instruction</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	126	<li><a href="#i_udiv">'<tt>udiv</tt>' Instruction</a></li>
				127	<li><a href="#i_sdiv">'<tt>sdiv</tt>' Instruction</a></li>
				128	<li><a href="#i_fdiv">'<tt>fdiv</tt>' Instruction</a></li>
				129	<li><a href="#i_urem">'<tt>urem</tt>' Instruction</a></li>
				130	<li><a href="#i_srem">'<tt>srem</tt>' Instruction</a></li>
				131	<li><a href="#i_frem">'<tt>frem</tt>' Instruction</a></li>
				132	</ol>
				133	</li>
				134	<li><a href="#bitwiseops">Bitwise Binary Operations</a>
				135	<ol>
				136	<li><a href="#i_shl">'<tt>shl</tt>' Instruction</a></li>
				137	<li><a href="#i_lshr">'<tt>lshr</tt>' Instruction</a></li>
				138	<li><a href="#i_ashr">'<tt>ashr</tt>' Instruction</a></li>
				139	<li><a href="#i_and">'<tt>and</tt>' Instruction</a></li>
				140	<li><a href="#i_or">'<tt>or</tt>' Instruction</a></li>
				141	<li><a href="#i_xor">'<tt>xor</tt>' Instruction</a></li>
				142	</ol>
				143	</li>
				144	<li><a href="#vectorops">Vector Operations</a>
				145	<ol>
				146	<li><a href="#i_extractelement">'<tt>extractelement</tt>' Instruction</a></li>
				147	<li><a href="#i_insertelement">'<tt>insertelement</tt>' Instruction</a></li>
				148	<li><a href="#i_shufflevector">'<tt>shufflevector</tt>' Instruction</a></li>
				149	</ol>
				150	</li>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	151	<li><a href="#aggregateops">Aggregate Operations</a>
				152	<ol>
				153	<li><a href="#i_extractvalue">'<tt>extractvalue</tt>' Instruction</a></li>
				154	<li><a href="#i_insertvalue">'<tt>insertvalue</tt>' Instruction</a></li>
				155	</ol>
				156	</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	157	<li><a href="#memoryops">Memory Access and Addressing Operations</a>
				158	<ol>
				159	<li><a href="#i_malloc">'<tt>malloc</tt>' Instruction</a></li>
				160	<li><a href="#i_free">'<tt>free</tt>' Instruction</a></li>
				161	<li><a href="#i_alloca">'<tt>alloca</tt>' Instruction</a></li>
				162	<li><a href="#i_load">'<tt>load</tt>' Instruction</a></li>
				163	<li><a href="#i_store">'<tt>store</tt>' Instruction</a></li>
				164	<li><a href="#i_getelementptr">'<tt>getelementptr</tt>' Instruction</a></li>
				165	</ol>
				166	</li>
				167	<li><a href="#convertops">Conversion Operations</a>
				168	<ol>
				169	<li><a href="#i_trunc">'<tt>trunc .. to</tt>' Instruction</a></li>
				170	<li><a href="#i_zext">'<tt>zext .. to</tt>' Instruction</a></li>
				171	<li><a href="#i_sext">'<tt>sext .. to</tt>' Instruction</a></li>
				172	<li><a href="#i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a></li>
				173	<li><a href="#i_fpext">'<tt>fpext .. to</tt>' Instruction</a></li>
				174	<li><a href="#i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a></li>
				175	<li><a href="#i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a></li>
				176	<li><a href="#i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a></li>
				177	<li><a href="#i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a></li>
				178	<li><a href="#i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a></li>
				179	<li><a href="#i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a></li>
				180	<li><a href="#i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a></li>
				181	</ol>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	182	</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	183	<li><a href="#otherops">Other Operations</a>
				184	<ol>
				185	<li><a href="#i_icmp">'<tt>icmp</tt>' Instruction</a></li>
				186	<li><a href="#i_fcmp">'<tt>fcmp</tt>' Instruction</a></li>
				187	<li><a href="#i_phi">'<tt>phi</tt>' Instruction</a></li>
				188	<li><a href="#i_select">'<tt>select</tt>' Instruction</a></li>
				189	<li><a href="#i_call">'<tt>call</tt>' Instruction</a></li>
				190	<li><a href="#i_va_arg">'<tt>va_arg</tt>' Instruction</a></li>
				191	</ol>
				192	</li>
				193	</ol>
				194	</li>
				195	<li><a href="#intrinsics">Intrinsic Functions</a>
				196	<ol>
				197	<li><a href="#int_varargs">Variable Argument Handling Intrinsics</a>
				198	<ol>
				199	<li><a href="#int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a></li>
				200	<li><a href="#int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a></li>
				201	<li><a href="#int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a></li>
				202	</ol>
				203	</li>
				204	<li><a href="#int_gc">Accurate Garbage Collection Intrinsics</a>
				205	<ol>
				206	<li><a href="#int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a></li>
				207	<li><a href="#int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a></li>
				208	<li><a href="#int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a></li>
				209	</ol>
				210	</li>
				211	<li><a href="#int_codegen">Code Generator Intrinsics</a>
				212	<ol>
				213	<li><a href="#int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a></li>
				214	<li><a href="#int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a></li>
				215	<li><a href="#int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a></li>
				216	<li><a href="#int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a></li>
				217	<li><a href="#int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a></li>
				218	<li><a href="#int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a></li>
				219	<li><a href="#int_readcyclecounter"><tt>llvm.readcyclecounter</tt>' Intrinsic</a></li>
				220	</ol>
				221	</li>
				222	<li><a href="#int_libc">Standard C Library Intrinsics</a>
				223	<ol>
				224	<li><a href="#int_memcpy">'<tt>llvm.memcpy.*</tt>' Intrinsic</a></li>
				225	<li><a href="#int_memmove">'<tt>llvm.memmove.*</tt>' Intrinsic</a></li>
				226	<li><a href="#int_memset">'<tt>llvm.memset.*</tt>' Intrinsic</a></li>
				227	<li><a href="#int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a></li>
				228	<li><a href="#int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a></li>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	229	<li><a href="#int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a></li>
				230	<li><a href="#int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a></li>
				231	<li><a href="#int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	232	</ol>
				233	</li>
				234	<li><a href="#int_manip">Bit Manipulation Intrinsics</a>
				235	<ol>
				236	<li><a href="#int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a></li>
				237	<li><a href="#int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic </a></li>
				238	<li><a href="#int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic </a></li>
				239	<li><a href="#int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic </a></li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	240	</ol>
				241	</li>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	242	<li><a href="#int_overflow">Arithmetic with Overflow Intrinsics</a>
				243	<ol>
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	244	<li><a href="#int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt> Intrinsics</a></li>
				245	<li><a href="#int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt> Intrinsics</a></li>
				246	<li><a href="#int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt> Intrinsics</a></li>
				247	<li><a href="#int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt> Intrinsics</a></li>
				248	<li><a href="#int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	249	<li><a href="#int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt> Intrinsics</a></li>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	250	</ol>
				251	</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	252	<li><a href="#int_debugger">Debugger intrinsics</a></li>
				253	<li><a href="#int_eh">Exception Handling intrinsics</a></li>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	254	<li><a href="#int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	255	<ol>
				256	<li><a href="#int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a></li>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	257	</ol>
				258	</li>
Bill Wendling	9127adb	2008-11-18 22:10:53 +0000	[diff] [blame]	259	<li><a href="#int_atomics">Atomic intrinsics</a>
				260	<ol>
				261	<li><a href="#int_memory_barrier"><tt>llvm.memory_barrier</tt></a></li>
				262	<li><a href="#int_atomic_cmp_swap"><tt>llvm.atomic.cmp.swap</tt></a></li>
				263	<li><a href="#int_atomic_swap"><tt>llvm.atomic.swap</tt></a></li>
				264	<li><a href="#int_atomic_load_add"><tt>llvm.atomic.load.add</tt></a></li>
				265	<li><a href="#int_atomic_load_sub"><tt>llvm.atomic.load.sub</tt></a></li>
				266	<li><a href="#int_atomic_load_and"><tt>llvm.atomic.load.and</tt></a></li>
				267	<li><a href="#int_atomic_load_nand"><tt>llvm.atomic.load.nand</tt></a></li>
				268	<li><a href="#int_atomic_load_or"><tt>llvm.atomic.load.or</tt></a></li>
				269	<li><a href="#int_atomic_load_xor"><tt>llvm.atomic.load.xor</tt></a></li>
				270	<li><a href="#int_atomic_load_max"><tt>llvm.atomic.load.max</tt></a></li>
				271	<li><a href="#int_atomic_load_min"><tt>llvm.atomic.load.min</tt></a></li>
				272	<li><a href="#int_atomic_load_umax"><tt>llvm.atomic.load.umax</tt></a></li>
				273	<li><a href="#int_atomic_load_umin"><tt>llvm.atomic.load.umin</tt></a></li>
				274	</ol>
				275	</li>
Reid Spencer	b043f67	2007-07-20 19:59:11 +0000	[diff] [blame]	276	<li><a href="#int_general">General intrinsics</a>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	277	<ol>
Reid Spencer	b043f67	2007-07-20 19:59:11 +0000	[diff] [blame]	278	<li><a href="#int_var_annotation">
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	279	'<tt>llvm.var.annotation</tt>' Intrinsic</a></li>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	280	<li><a href="#int_annotation">
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	281	'<tt>llvm.annotation.*</tt>' Intrinsic</a></li>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	282	<li><a href="#int_trap">
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	283	'<tt>llvm.trap</tt>' Intrinsic</a></li>
				284	<li><a href="#int_stackprotector">
				285	'<tt>llvm.stackprotector</tt>' Intrinsic</a></li>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	286	</ol>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	287	</li>
				288	</ol>
				289	</li>
				290	</ol>
				291
				292	<div class="doc_author">
				293	<p>Written by <a href="mailto:sabre@nondot.org">Chris Lattner</a>
				294	and <a href="mailto:vadve@cs.uiuc.edu">Vikram Adve</a></p>
				295	</div>
				296
				297	<!-- *********************************************************************** -->
				298	<div class="doc_section"> <a name="abstract">Abstract </a></div>
				299	<!-- *********************************************************************** -->
				300
				301	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	302
				303	<p>This document is a reference manual for the LLVM assembly language. LLVM is
				304	a Static Single Assignment (SSA) based representation that provides type
				305	safety, low-level operations, flexibility, and the capability of representing
				306	'all' high-level languages cleanly. It is the common code representation
				307	used throughout all phases of the LLVM compilation strategy.</p>
				308
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	309	</div>
				310
				311	<!-- *********************************************************************** -->
				312	<div class="doc_section"> <a name="introduction">Introduction</a> </div>
				313	<!-- *********************************************************************** -->
				314
				315	<div class="doc_text">
				316
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	317	<p>The LLVM code representation is designed to be used in three different forms:
				318	as an in-memory compiler IR, as an on-disk bitcode representation (suitable
				319	for fast loading by a Just-In-Time compiler), and as a human readable
				320	assembly language representation. This allows LLVM to provide a powerful
				321	intermediate representation for efficient compiler transformations and
				322	analysis, while providing a natural means to debug and visualize the
				323	transformations. The three different forms of LLVM are all equivalent. This
				324	document describes the human readable representation and notation.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	325
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	326	<p>The LLVM representation aims to be light-weight and low-level while being
				327	expressive, typed, and extensible at the same time. It aims to be a
				328	"universal IR" of sorts, by being at a low enough level that high-level ideas
				329	may be cleanly mapped to it (similar to how microprocessors are "universal
				330	IR's", allowing many source languages to be mapped to them). By providing
				331	type information, LLVM can be used as the target of optimizations: for
				332	example, through pointer analysis, it can be proven that a C automatic
				333	variable is never accessed outside of the current function... allowing it to
				334	be promoted to a simple SSA value instead of a memory location.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	335
				336	</div>
				337
				338	<!-- _______________________________________________________________________ -->
				339	<div class="doc_subsubsection"> <a name="wellformed">Well-Formedness</a> </div>
				340
				341	<div class="doc_text">
				342
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	343	<p>It is important to note that this document describes 'well formed' LLVM
				344	assembly language. There is a difference between what the parser accepts and
				345	what is considered 'well formed'. For example, the following instruction is
				346	syntactically okay, but not well formed:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	347
				348	<div class="doc_code">
				349	<pre>
				350	%x = <a href="#i_add">add</a> i32 1, %x
				351	</pre>
				352	</div>
				353
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	354	<p>...because the definition of <tt>%x</tt> does not dominate all of its
				355	uses. The LLVM infrastructure provides a verification pass that may be used
				356	to verify that an LLVM module is well formed. This pass is automatically run
				357	by the parser after parsing input assembly and by the optimizer before it
				358	outputs bitcode. The violations pointed out by the verifier pass indicate
				359	bugs in transformation passes or input to the parser.</p>
				360
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	361	</div>
				362
Chris Lattner	a83fdc0	2007-10-03 17:34:29 +0000	[diff] [blame]	363	<!-- Describe the typesetting conventions here. -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	364
				365	<!-- *********************************************************************** -->
				366	<div class="doc_section"> <a name="identifiers">Identifiers</a> </div>
				367	<!-- *********************************************************************** -->
				368
				369	<div class="doc_text">
				370
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	371	<p>LLVM identifiers come in two basic types: global and local. Global
				372	identifiers (functions, global variables) begin with the <tt>'@'</tt>
				373	character. Local identifiers (register names, types) begin with
				374	the <tt>'%'</tt> character. Additionally, there are three different formats
				375	for identifiers, for different purposes:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	376
				377	<ol>
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	378	<li>Named values are represented as a string of characters with their prefix.
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	379	For example, <tt>%foo</tt>, <tt>@DivisionByZero</tt>,
				380	<tt>%a.really.long.identifier</tt>. The actual regular expression used is
				381	'<tt>[%@][a-zA-Z$._][a-zA-Z$._0-9]*</tt>'. Identifiers which require
				382	other characters in their names can be surrounded with quotes. Special
				383	characters may be escaped using <tt>"\xx"</tt> where <tt>xx</tt> is the
				384	ASCII code for the character in hexadecimal. In this way, any character
				385	can be used in a name value, even quotes themselves.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	386
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	387	<li>Unnamed values are represented as an unsigned numeric value with their
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	388	prefix. For example, <tt>%12</tt>, <tt>@2</tt>, <tt>%44</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	389
				390	<li>Constants, which are described in a <a href="#constants">section about
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	391	constants</a>, below.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	392	</ol>
				393
Reid Spencer	c8245b0	2007-08-07 14:34:28 +0000	[diff] [blame]	394	<p>LLVM requires that values start with a prefix for two reasons: Compilers
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	395	don't need to worry about name clashes with reserved words, and the set of
				396	reserved words may be expanded in the future without penalty. Additionally,
				397	unnamed identifiers allow a compiler to quickly come up with a temporary
				398	variable without having to avoid symbol table conflicts.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	399
				400	<p>Reserved words in LLVM are very similar to reserved words in other
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	401	languages. There are keywords for different opcodes
				402	('<tt><a href="#i_add">add</a></tt>',
				403	'<tt><a href="#i_bitcast">bitcast</a></tt>',
				404	'<tt><a href="#i_ret">ret</a></tt>', etc...), for primitive type names
				405	('<tt><a href="#t_void">void</a></tt>',
				406	'<tt><a href="#t_primitive">i32</a></tt>', etc...), and others. These
				407	reserved words cannot conflict with variable names, because none of them
				408	start with a prefix character (<tt>'%'</tt> or <tt>'@'</tt>).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	409
				410	<p>Here is an example of LLVM code to multiply the integer variable
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	411	'<tt>%X</tt>' by 8:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	412
				413	<p>The easy way:</p>
				414
				415	<div class="doc_code">
				416	<pre>
				417	%result = <a href="#i_mul">mul</a> i32 %X, 8
				418	</pre>
				419	</div>
				420
				421	<p>After strength reduction:</p>
				422
				423	<div class="doc_code">
				424	<pre>
				425	%result = <a href="#i_shl">shl</a> i32 %X, i8 3
				426	</pre>
				427	</div>
				428
				429	<p>And the hard way:</p>
				430
				431	<div class="doc_code">
				432	<pre>
				433	<a href="#i_add">add</a> i32 %X, %X <i>; yields {i32}:%0</i>
				434	<a href="#i_add">add</a> i32 %0, %0 <i>; yields {i32}:%1</i>
				435	%result = <a href="#i_add">add</a> i32 %1, %1
				436	</pre>
				437	</div>
				438
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	439	<p>This last way of multiplying <tt>%X</tt> by 8 illustrates several important
				440	lexical features of LLVM:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	441
				442	<ol>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	443	<li>Comments are delimited with a '<tt>;</tt>' and go until the end of
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	444	line.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	445
				446	<li>Unnamed temporaries are created when the result of a computation is not
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	447	assigned to a named value.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	448
				449	<li>Unnamed temporaries are numbered sequentially</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	450	</ol>
				451
				452	<p>...and it also shows a convention that we follow in this document. When
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	453	demonstrating instructions, we will follow an instruction with a comment that
				454	defines the type and name of value produced. Comments are shown in italic
				455	text.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	456
				457	</div>
				458
				459	<!-- *********************************************************************** -->
				460	<div class="doc_section"> <a name="highlevel">High Level Structure</a> </div>
				461	<!-- *********************************************************************** -->
				462
				463	<!-- ======================================================================= -->
				464	<div class="doc_subsection"> <a name="modulestructure">Module Structure</a>
				465	</div>
				466
				467	<div class="doc_text">
				468
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	469	<p>LLVM programs are composed of "Module"s, each of which is a translation unit
				470	of the input programs. Each module consists of functions, global variables,
				471	and symbol table entries. Modules may be combined together with the LLVM
				472	linker, which merges function (and global variable) definitions, resolves
				473	forward declarations, and merges symbol table entries. Here is an example of
				474	the "hello world" module:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	475
				476	<div class="doc_code">
				477	<pre><i>; Declare the string constant as a global constant...</i>
				478	<a href="#identifiers">@.LC0</a> = <a href="#linkage_internal">internal</a> <a
				479	href="#globalvars">constant</a> <a href="#t_array">[13 x i8]</a> c"hello world\0A\00" <i>; [13 x i8]*</i>
				480
				481	<i>; External declaration of the puts function</i>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	482	<a href="#functionstructure">declare</a> i32 @puts(i8 ) <i>; i32(i8 )* </i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	483
				484	<i>; Definition of main function</i>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	485	define i32 @main() { <i>; i32()* </i>
Dan Gohman	0185238	2009-01-04 23:44:43 +0000	[diff] [blame]	486	<i>; Convert [13 x i8]* to i8 *...</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	487	%cast210 = <a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	488	href="#i_getelementptr">getelementptr</a> [13 x i8]* @.LC0, i64 0, i64 0 <i>; i8 *</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	489
				490	<i>; Call puts function to write out the string to stdout...</i>
				491	<a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	492	href="#i_call">call</a> i32 @puts(i8 * %cast210) <i>; i32</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	493	<a
				494	href="#i_ret">ret</a> i32 0<br>}<br>
				495	</pre>
				496	</div>
				497
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	498	<p>This example is made up of a <a href="#globalvars">global variable</a> named
				499	"<tt>.LC0</tt>", an external declaration of the "<tt>puts</tt>" function, and
				500	a <a href="#functionstructure">function definition</a> for
				501	"<tt>main</tt>".</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	502
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	503	<p>In general, a module is made up of a list of global values, where both
				504	functions and global variables are global values. Global values are
				505	represented by a pointer to a memory location (in this case, a pointer to an
				506	array of char, and a pointer to a function), and have one of the
				507	following <a href="#linkage">linkage types</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	508
				509	</div>
				510
				511	<!-- ======================================================================= -->
				512	<div class="doc_subsection">
				513	<a name="linkage">Linkage Types</a>
				514	</div>
				515
				516	<div class="doc_text">
				517
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	518	<p>All Global Variables and Functions have one of the following types of
				519	linkage:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	520
				521	<dl>
Rafael Espindola	a168fc9	2009-01-15 20:18:42 +0000	[diff] [blame]	522	<dt><tt><b><a name="linkage_private">private</a></b></tt>: </dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	523	<dd>Global values with private linkage are only directly accessible by objects
				524	in the current module. In particular, linking code into a module with an
				525	private global value may cause the private to be renamed as necessary to
				526	avoid collisions. Because the symbol is private to the module, all
				527	references can be updated. This doesn't show up in any symbol table in the
				528	object file.</dd>
Rafael Espindola	a168fc9	2009-01-15 20:18:42 +0000	[diff] [blame]	529
Bill Wendling	41a0785	2009-07-20 01:03:30 +0000	[diff] [blame]	530	<dt><tt><b><a name="linkage_linker_private">linker_private</a></b></tt>: </dt>
Bill Wendling	41a0785	2009-07-20 01:03:30 +0000	[diff] [blame]	531	<dd>Similar to private, but the symbol is passed through the assembler and
				532	removed by the linker after evaluation.</dd>
				533
Dale Johannesen	96e7e09	2008-05-23 23:13:41 +0000	[diff] [blame]	534	<dt><tt><b><a name="linkage_internal">internal</a></b></tt>: </dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	535	<dd>Similar to private, but the value shows as a local symbol
				536	(<tt>STB_LOCAL</tt> in the case of ELF) in the object file. This
				537	corresponds to the notion of the '<tt>static</tt>' keyword in C.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	538
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	539	<dt><tt><b><a name="linkage_available_externally">available_externally</a></b></tt>: </dt>
Chris Lattner	6843344	2009-04-13 05:44:34 +0000	[diff] [blame]	540	<dd>Globals with "<tt>available_externally</tt>" linkage are never emitted
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	541	into the object file corresponding to the LLVM module. They exist to
				542	allow inlining and other optimizations to take place given knowledge of
				543	the definition of the global, which is known to be somewhere outside the
				544	module. Globals with <tt>available_externally</tt> linkage are allowed to
				545	be discarded at will, and are otherwise the same as <tt>linkonce_odr</tt>.
				546	This linkage type is only allowed on definitions, not declarations.</dd>
Chris Lattner	6843344	2009-04-13 05:44:34 +0000	[diff] [blame]	547
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	548	<dt><tt><b><a name="linkage_linkonce">linkonce</a></b></tt>: </dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	549	<dd>Globals with "<tt>linkonce</tt>" linkage are merged with other globals of
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	550	the same name when linkage occurs. This is typically used to implement
				551	inline functions, templates, or other code which must be generated in each
				552	translation unit that uses it. Unreferenced <tt>linkonce</tt> globals are
				553	allowed to be discarded.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	554
				555	<dt><tt><b><a name="linkage_weak">weak</a></b></tt>: </dt>
Chris Lattner	7215c7f	2009-08-05 05:21:07 +0000	[diff] [blame]	556	<dd>"<tt>weak</tt>" linkage has the same merging semantics as
				557	<tt>linkonce</tt> linkage, except that unreferenced globals with
				558	<tt>weak</tt> linkage may not be discarded. This is used for globals that
				559	are declared "weak" in C source code.</dd>
				560
				561	<dt><tt><b><a name="linkage_common">common</a></b></tt>: </dt>
				562	<dd>"<tt>common</tt>" linkage is most similar to "<tt>weak</tt>" linkage, but
				563	they are used for tentative definitions in C, such as "<tt>int X;</tt>" at
				564	global scope.
				565	Symbols with "<tt>common</tt>" linkage are merged in the same way as
				566	<tt>weak symbols</tt>, and they may not be deleted if unreferenced.
Chris Lattner	83c4a71	2009-08-05 05:41:44 +0000	[diff] [blame]	567	<tt>common</tt> symbols may not have an explicit section,
				568	must have a zero initializer, and may not be marked '<a
				569	href="#globalvars"><tt>constant</tt></a>'. Functions and aliases may not
				570	have common linkage.</dd>
Chris Lattner	7215c7f	2009-08-05 05:21:07 +0000	[diff] [blame]	571
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	572
				573	<dt><tt><b><a name="linkage_appending">appending</a></b></tt>: </dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	574	<dd>"<tt>appending</tt>" linkage may only be applied to global variables of
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	575	pointer to array type. When two global variables with appending linkage
				576	are linked together, the two global arrays are appended together. This is
				577	the LLVM, typesafe, equivalent of having the system linker append together
				578	"sections" with identical names when .o files are linked.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	579
				580	<dt><tt><b><a name="linkage_externweak">extern_weak</a></b></tt>: </dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	581	<dd>The semantics of this linkage follow the ELF object file model: the symbol
				582	is weak until linked, if not linked, the symbol becomes null instead of
				583	being an undefined reference.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	584
Duncan Sands	19d161f	2009-03-07 15:45:40 +0000	[diff] [blame]	585	<dt><tt><b><a name="linkage_linkonce">linkonce_odr</a></b></tt>: </dt>
Duncan Sands	19d161f	2009-03-07 15:45:40 +0000	[diff] [blame]	586	<dt><tt><b><a name="linkage_weak">weak_odr</a></b></tt>: </dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	587	<dd>Some languages allow differing globals to be merged, such as two functions
				588	with different semantics. Other languages, such as <tt>C++</tt>, ensure
				589	that only equivalent globals are ever merged (the "one definition rule" -
				590	"ODR"). Such languages can use the <tt>linkonce_odr</tt>
				591	and <tt>weak_odr</tt> linkage types to indicate that the global will only
				592	be merged with equivalent globals. These linkage types are otherwise the
				593	same as their non-<tt>odr</tt> versions.</dd>
Duncan Sands	19d161f	2009-03-07 15:45:40 +0000	[diff] [blame]	594
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	595	<dt><tt><b><a name="linkage_external">externally visible</a></b></tt>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	596	<dd>If none of the above identifiers are used, the global is externally
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	597	visible, meaning that it participates in linkage and can be used to
				598	resolve external symbol references.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	599	</dl>
				600
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	601	<p>The next two types of linkage are targeted for Microsoft Windows platform
				602	only. They are designed to support importing (exporting) symbols from (to)
				603	DLLs (Dynamic Link Libraries).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	604
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	605	<dl>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	606	<dt><tt><b><a name="linkage_dllimport">dllimport</a></b></tt>: </dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	607	<dd>"<tt>dllimport</tt>" linkage causes the compiler to reference a function
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	608	or variable via a global pointer to a pointer that is set up by the DLL
				609	exporting the symbol. On Microsoft Windows targets, the pointer name is
				610	formed by combining <code>__imp_</code> and the function or variable
				611	name.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	612
				613	<dt><tt><b><a name="linkage_dllexport">dllexport</a></b></tt>: </dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	614	<dd>"<tt>dllexport</tt>" linkage causes the compiler to provide a global
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	615	pointer to a pointer in a DLL, so that it can be referenced with the
				616	<tt>dllimport</tt> attribute. On Microsoft Windows targets, the pointer
				617	name is formed by combining <code>__imp_</code> and the function or
				618	variable name.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	619	</dl>
				620
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	621	<p>For example, since the "<tt>.LC0</tt>" variable is defined to be internal, if
				622	another module defined a "<tt>.LC0</tt>" variable and was linked with this
				623	one, one of the two would be renamed, preventing a collision. Since
				624	"<tt>main</tt>" and "<tt>puts</tt>" are external (i.e., lacking any linkage
				625	declarations), they are accessible outside of the current module.</p>
				626
				627	<p>It is illegal for a function <i>declaration</i> to have any linkage type
				628	other than "externally visible", <tt>dllimport</tt>
				629	or <tt>extern_weak</tt>.</p>
				630
Duncan Sands	19d161f	2009-03-07 15:45:40 +0000	[diff] [blame]	631	<p>Aliases can have only <tt>external</tt>, <tt>internal</tt>, <tt>weak</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	632	or <tt>weak_odr</tt> linkages.</p>
				633
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	634	</div>
				635
				636	<!-- ======================================================================= -->
				637	<div class="doc_subsection">
				638	<a name="callingconv">Calling Conventions</a>
				639	</div>
				640
				641	<div class="doc_text">
				642
				643	<p>LLVM <a href="#functionstructure">functions</a>, <a href="#i_call">calls</a>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	644	and <a href="#i_invoke">invokes</a> can all have an optional calling
				645	convention specified for the call. The calling convention of any pair of
				646	dynamic caller/callee must match, or the behavior of the program is
				647	undefined. The following calling conventions are supported by LLVM, and more
				648	may be added in the future:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	649
				650	<dl>
				651	<dt><b>"<tt>ccc</tt>" - The C calling convention</b>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	652	<dd>This calling convention (the default if no other calling convention is
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	653	specified) matches the target C calling conventions. This calling
				654	convention supports varargs function calls and tolerates some mismatch in
				655	the declared prototype and implemented declaration of the function (as
				656	does normal C).</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	657
				658	<dt><b>"<tt>fastcc</tt>" - The fast calling convention</b>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	659	<dd>This calling convention attempts to make calls as fast as possible
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	660	(e.g. by passing things in registers). This calling convention allows the
				661	target to use whatever tricks it wants to produce fast code for the
				662	target, without having to conform to an externally specified ABI
				663	(Application Binary Interface). Implementations of this convention should
				664	allow arbitrary <a href="CodeGenerator.html#tailcallopt">tail call
				665	optimization</a> to be supported. This calling convention does not
				666	support varargs and requires the prototype of all callees to exactly match
				667	the prototype of the function definition.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	668
				669	<dt><b>"<tt>coldcc</tt>" - The cold calling convention</b>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	670	<dd>This calling convention attempts to make code in the caller as efficient
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	671	as possible under the assumption that the call is not commonly executed.
				672	As such, these calls often preserve all registers so that the call does
				673	not break any live ranges in the caller side. This calling convention
				674	does not support varargs and requires the prototype of all callees to
				675	exactly match the prototype of the function definition.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	676
				677	<dt><b>"<tt>cc <<em>n</em>></tt>" - Numbered convention</b>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	678	<dd>Any calling convention may be specified by number, allowing
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	679	target-specific calling conventions to be used. Target specific calling
				680	conventions start at 64.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	681	</dl>
				682
				683	<p>More calling conventions can be added/defined on an as-needed basis, to
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	684	support Pascal conventions or any other well-known target-independent
				685	convention.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	686
				687	</div>
				688
				689	<!-- ======================================================================= -->
				690	<div class="doc_subsection">
				691	<a name="visibility">Visibility Styles</a>
				692	</div>
				693
				694	<div class="doc_text">
				695
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	696	<p>All Global Variables and Functions have one of the following visibility
				697	styles:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	698
				699	<dl>
				700	<dt><b>"<tt>default</tt>" - Default style</b>:</dt>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	701	<dd>On targets that use the ELF object file format, default visibility means
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	702	that the declaration is visible to other modules and, in shared libraries,
				703	means that the declared entity may be overridden. On Darwin, default
				704	visibility means that the declaration is visible to other modules. Default
				705	visibility corresponds to "external linkage" in the language.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	706
				707	<dt><b>"<tt>hidden</tt>" - Hidden style</b>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	708	<dd>Two declarations of an object with hidden visibility refer to the same
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	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
				711	table, so no other module (executable or shared library) can reference it
				712	directly.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	713
				714	<dt><b>"<tt>protected</tt>" - Protected style</b>:</dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	715	<dd>On ELF, protected visibility indicates that the symbol will be placed in
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	716	the dynamic symbol table, but that references within the defining module
				717	will bind to the local symbol. That is, the symbol cannot be overridden by
				718	another module.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	719	</dl>
				720
				721	</div>
				722
				723	<!-- ======================================================================= -->
				724	<div class="doc_subsection">
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	725	<a name="namedtypes">Named Types</a>
				726	</div>
				727
				728	<div class="doc_text">
				729
				730	<p>LLVM IR allows you to specify name aliases for certain types. This can make
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	731	it easier to read the IR and make the IR more condensed (particularly when
				732	recursive types are involved). An example of a name specification is:</p>
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	733
				734	<div class="doc_code">
				735	<pre>
				736	%mytype = type { %mytype*, i32 }
				737	</pre>
				738	</div>
				739
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	740	<p>You may give a name to any <a href="#typesystem">type</a> except
				741	"<a href="t_void">void</a>". Type name aliases may be used anywhere a type
				742	is expected with the syntax "%mytype".</p>
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	743
				744	<p>Note that type names are aliases for the structural type that they indicate,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	745	and that you can therefore specify multiple names for the same type. This
				746	often leads to confusing behavior when dumping out a .ll file. Since LLVM IR
				747	uses structural typing, the name is not part of the type. When printing out
				748	LLVM IR, the printer will pick <em>one name</em> to render all types of a
				749	particular shape. This means that if you have code where two different
				750	source types end up having the same LLVM type, that the dumper will sometimes
				751	print the "wrong" or unexpected type. This is an important design point and
				752	isn't going to change.</p>
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	753
				754	</div>
				755
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	756	<!-- ======================================================================= -->
				757	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	758	<a name="globalvars">Global Variables</a>
				759	</div>
				760
				761	<div class="doc_text">
				762
				763	<p>Global variables define regions of memory allocated at compilation time
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	764	instead of run-time. Global variables may optionally be initialized, may
				765	have an explicit section to be placed in, and may have an optional explicit
				766	alignment specified. A variable may be defined as "thread_local", which
				767	means that it will not be shared by threads (each thread will have a
				768	separated copy of the variable). A variable may be defined as a global
				769	"constant," which indicates that the contents of the variable
				770	will <b>never</b> be modified (enabling better optimization, allowing the
				771	global data to be placed in the read-only section of an executable, etc).
				772	Note that variables that need runtime initialization cannot be marked
				773	"constant" as there is a store to the variable.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	774
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	775	<p>LLVM explicitly allows <em>declarations</em> of global variables to be marked
				776	constant, even if the final definition of the global is not. This capability
				777	can be used to enable slightly better optimization of the program, but
				778	requires the language definition to guarantee that optimizations based on the
				779	'constantness' are valid for the translation units that do not include the
				780	definition.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	781
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	782	<p>As SSA values, global variables define pointer values that are in scope
				783	(i.e. they dominate) all basic blocks in the program. Global variables
				784	always define a pointer to their "content" type because they describe a
				785	region of memory, and all memory objects in LLVM are accessed through
				786	pointers.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	787
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	788	<p>A global variable may be declared to reside in a target-specific numbered
				789	address space. For targets that support them, address spaces may affect how
				790	optimizations are performed and/or what target instructions are used to
				791	access the variable. The default address space is zero. The address space
				792	qualifier must precede any other attributes.</p>
Christopher Lamb	dd0049d	2007-12-11 09:31:00 +0000	[diff] [blame]	793
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	794	<p>LLVM allows an explicit section to be specified for globals. If the target
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	795	supports it, it will emit globals to the section specified.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	796
				797	<p>An explicit alignment may be specified for a global. If not present, or if
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	798	the alignment is set to zero, the alignment of the global is set by the
				799	target to whatever it feels convenient. If an explicit alignment is
				800	specified, the global is forced to have at least that much alignment. All
				801	alignments must be a power of 2.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	802
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	803	<p>For example, the following defines a global in a numbered address space with
				804	an initializer, section, and alignment:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	805
				806	<div class="doc_code">
				807	<pre>
Dan Gohman	21ef02c	2009-01-11 00:40:00 +0000	[diff] [blame]	808	@G = addrspace(5) constant float 1.0, section "foo", align 4
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	809	</pre>
				810	</div>
				811
				812	</div>
				813
				814
				815	<!-- ======================================================================= -->
				816	<div class="doc_subsection">
				817	<a name="functionstructure">Functions</a>
				818	</div>
				819
				820	<div class="doc_text">
				821
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	822	<p>LLVM function definitions consist of the "<tt>define</tt>" keyord, an
				823	optional <a href="#linkage">linkage type</a>, an optional
				824	<a href="#visibility">visibility style</a>, an optional
				825	<a href="#callingconv">calling convention</a>, a return type, an optional
				826	<a href="#paramattrs">parameter attribute</a> for the return type, a function
				827	name, a (possibly empty) argument list (each with optional
				828	<a href="#paramattrs">parameter attributes</a>), optional
				829	<a href="#fnattrs">function attributes</a>, an optional section, an optional
				830	alignment, an optional <a href="#gc">garbage collector name</a>, an opening
				831	curly brace, a list of basic blocks, and a closing curly brace.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	832
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	833	<p>LLVM function declarations consist of the "<tt>declare</tt>" keyword, an
				834	optional <a href="#linkage">linkage type</a>, an optional
				835	<a href="#visibility">visibility style</a>, an optional
				836	<a href="#callingconv">calling convention</a>, a return type, an optional
				837	<a href="#paramattrs">parameter attribute</a> for the return type, a function
				838	name, a possibly empty list of arguments, an optional alignment, and an
				839	optional <a href="#gc">garbage collector name</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	840
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	841	<p>A function definition contains a list of basic blocks, forming the CFG
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	842	(Control Flow Graph) for the function. Each basic block may optionally start
				843	with a label (giving the basic block a symbol table entry), contains a list
				844	of instructions, and ends with a <a href="#terminators">terminator</a>
				845	instruction (such as a branch or function return).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	846
				847	<p>The first basic block in a function is special in two ways: it is immediately
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	848	executed on entrance to the function, and it is not allowed to have
				849	predecessor basic blocks (i.e. there can not be any branches to the entry
				850	block of a function). Because the block can have no predecessors, it also
				851	cannot have any <a href="#i_phi">PHI nodes</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	852
				853	<p>LLVM allows an explicit section to be specified for functions. If the target
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	854	supports it, it will emit functions to the section specified.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	855
				856	<p>An explicit alignment may be specified for a function. If not present, or if
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	857	the alignment is set to zero, the alignment of the function is set by the
				858	target to whatever it feels convenient. If an explicit alignment is
				859	specified, the function is forced to have at least that much alignment. All
				860	alignments must be a power of 2.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	861
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	862	<h5>Syntax:</h5>
Devang Patel	d0bfcc7	2008-10-07 17:48:33 +0000	[diff] [blame]	863	<div class="doc_code">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	864	<pre>
Chris Lattner	1e5c5cd0	2008-10-13 16:55:18 +0000	[diff] [blame]	865	define [<a href="#linkage">linkage</a>] [<a href="#visibility">visibility</a>]
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	866	[<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>]
				867	<ResultType> @<FunctionName> ([argument list])
				868	[<a href="#fnattrs">fn Attrs</a>] [section "name"] [align N]
				869	[<a href="#gc">gc</a>] { ... }
				870	</pre>
Devang Patel	d0bfcc7	2008-10-07 17:48:33 +0000	[diff] [blame]	871	</div>
				872
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	873	</div>
				874
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	875	<!-- ======================================================================= -->
				876	<div class="doc_subsection">
				877	<a name="aliasstructure">Aliases</a>
				878	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	879
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	880	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	881
				882	<p>Aliases act as "second name" for the aliasee value (which can be either
				883	function, global variable, another alias or bitcast of global value). Aliases
				884	may have an optional <a href="#linkage">linkage type</a>, and an
				885	optional <a href="#visibility">visibility style</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	886
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	887	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	888	<div class="doc_code">
				889	<pre>
Duncan Sands	d7bfabf	2008-09-12 20:48:21 +0000	[diff] [blame]	890	@<Name> = alias [Linkage] [Visibility] <AliaseeTy> @<Aliasee>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	891	</pre>
				892	</div>
				893
				894	</div>
				895
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	896	<!-- ======================================================================= -->
				897	<div class="doc_subsection"><a name="paramattrs">Parameter Attributes</a></div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	898
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	899	<div class="doc_text">
				900
				901	<p>The return type and each parameter of a function type may have a set of
				902	<i>parameter attributes</i> associated with them. Parameter attributes are
				903	used to communicate additional information about the result or parameters of
				904	a function. Parameter attributes are considered to be part of the function,
				905	not of the function type, so functions with different parameter attributes
				906	can have the same function type.</p>
				907
				908	<p>Parameter attributes are simple keywords that follow the type specified. If
				909	multiple parameter attributes are needed, they are space separated. For
				910	example:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	911
				912	<div class="doc_code">
				913	<pre>
Nick Lewycky	3022a74	2009-02-15 23:06:14 +0000	[diff] [blame]	914	declare i32 @printf(i8* noalias nocapture, ...)
Chris Lattner	f33b845	2008-10-04 18:33:34 +0000	[diff] [blame]	915	declare i32 @atoi(i8 zeroext)
				916	declare signext i8 @returns_signed_char()
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	917	</pre>
				918	</div>
				919
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	920	<p>Note that any attributes for the function result (<tt>nounwind</tt>,
				921	<tt>readonly</tt>) come immediately after the argument list.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	922
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	923	<p>Currently, only the following parameter attributes are defined:</p>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	924
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	925	<dl>
				926	<dt><tt>zeroext</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	927	<dd>This indicates to the code generator that the parameter or return value
				928	should be zero-extended to a 32-bit value by the caller (for a parameter)
				929	or the callee (for a return value).</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	930
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	931	<dt><tt>signext</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	932	<dd>This indicates to the code generator that the parameter or return value
				933	should be sign-extended to a 32-bit value by the caller (for a parameter)
				934	or the callee (for a return value).</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	935
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	936	<dt><tt>inreg</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	937	<dd>This indicates that this parameter or return value should be treated in a
				938	special target-dependent fashion during while emitting code for a function
				939	call or return (usually, by putting it in a register as opposed to memory,
				940	though some targets use it to distinguish between two different kinds of
				941	registers). Use of this attribute is target-specific.</dd>
Chris Lattner	275e6be	2008-01-11 06:20:47 +0000	[diff] [blame]	942
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	943	<dt><tt><a name="byval">byval</a></tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	944	<dd>This indicates that the pointer parameter should really be passed by value
				945	to the function. The attribute implies that a hidden copy of the pointee
				946	is made between the caller and the callee, so the callee is unable to
				947	modify the value in the callee. This attribute is only valid on LLVM
				948	pointer arguments. It is generally used to pass structs and arrays by
				949	value, but is also valid on pointers to scalars. The copy is considered
				950	to belong to the caller not the callee (for example,
				951	<tt><a href="#readonly">readonly</a></tt> functions should not write to
				952	<tt>byval</tt> parameters). This is not a valid attribute for return
				953	values. The byval attribute also supports specifying an alignment with
				954	the align attribute. This has a target-specific effect on the code
				955	generator that usually indicates a desired alignment for the synthesized
				956	stack slot.</dd>
				957
				958	<dt><tt>sret</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	959	<dd>This indicates that the pointer parameter specifies the address of a
				960	structure that is the return value of the function in the source program.
				961	This pointer must be guaranteed by the caller to be valid: loads and
				962	stores to the structure may be assumed by the callee to not to trap. This
				963	may only be applied to the first parameter. This is not a valid attribute
				964	for return values. </dd>
				965
				966	<dt><tt>noalias</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	967	<dd>This indicates that the pointer does not alias any global or any other
				968	parameter. The caller is responsible for ensuring that this is the
				969	case. On a function return value, <tt>noalias</tt> additionally indicates
				970	that the pointer does not alias any other pointers visible to the
				971	caller. For further details, please see the discussion of the NoAlias
				972	response in
				973	<a href="http://llvm.org/docs/AliasAnalysis.html#MustMayNo">alias
				974	analysis</a>.</dd>
				975
				976	<dt><tt>nocapture</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	977	<dd>This indicates that the callee does not make any copies of the pointer
				978	that outlive the callee itself. This is not a valid attribute for return
				979	values.</dd>
				980
				981	<dt><tt>nest</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	982	<dd>This indicates that the pointer parameter can be excised using the
				983	<a href="#int_trampoline">trampoline intrinsics</a>. This is not a valid
				984	attribute for return values.</dd>
				985	</dl>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	986
				987	</div>
				988
				989	<!-- ======================================================================= -->
				990	<div class="doc_subsection">
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	991	<a name="gc">Garbage Collector Names</a>
				992	</div>
				993
				994	<div class="doc_text">
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	995
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	996	<p>Each function may specify a garbage collector name, which is simply a
				997	string:</p>
				998
				999	<div class="doc_code">
				1000	<pre>
				1001	define void @f() gc "name" { ...
				1002	</pre>
				1003	</div>
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	1004
				1005	<p>The compiler declares the supported values of <i>name</i>. Specifying a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1006	collector which will cause the compiler to alter its output in order to
				1007	support the named garbage collection algorithm.</p>
				1008
Gordon Henriksen	13fe5e3	2007-12-10 03:18:06 +0000	[diff] [blame]	1009	</div>
				1010
				1011	<!-- ======================================================================= -->
				1012	<div class="doc_subsection">
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	1013	<a name="fnattrs">Function Attributes</a>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	1014	</div>
				1015
				1016	<div class="doc_text">
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	1017
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1018	<p>Function attributes are set to communicate additional information about a
				1019	function. Function attributes are considered to be part of the function, not
				1020	of the function type, so functions with different parameter attributes can
				1021	have the same function type.</p>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	1022
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1023	<p>Function attributes are simple keywords that follow the type specified. If
				1024	multiple attributes are needed, they are space separated. For example:</p>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	1025
				1026	<div class="doc_code">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1027	<pre>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	1028	define void @f() noinline { ... }
				1029	define void @f() alwaysinline { ... }
				1030	define void @f() alwaysinline optsize { ... }
				1031	define void @f() optsize
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1032	</pre>
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	1033	</div>
				1034
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1035	<dl>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1036	<dt><tt>alwaysinline</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1037	<dd>This attribute indicates that the inliner should attempt to inline this
				1038	function into callers whenever possible, ignoring any active inlining size
				1039	threshold for this caller.</dd>
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1040
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1041	<dt><tt>noinline</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1042	<dd>This attribute indicates that the inliner should never inline this
				1043	function in any situation. This attribute may not be used together with
				1044	the <tt>alwaysinline</tt> attribute.</dd>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	1045
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1046	<dt><tt>optsize</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1047	<dd>This attribute suggests that optimization passes and code generator passes
				1048	make choices that keep the code size of this function low, and otherwise
				1049	do optimizations specifically to reduce code size.</dd>
Devang Patel	008cd3e	2008-09-26 23:51:19 +0000	[diff] [blame]	1050
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1051	<dt><tt>noreturn</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1052	<dd>This function attribute indicates that the function never returns
				1053	normally. This produces undefined behavior at runtime if the function
				1054	ever does dynamically return.</dd>
Bill Wendling	dfaabba	2008-11-13 01:02:51 +0000	[diff] [blame]	1055
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1056	<dt><tt>nounwind</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1057	<dd>This function attribute indicates that the function never returns with an
				1058	unwind or exceptional control flow. If the function does unwind, its
				1059	runtime behavior is undefined.</dd>
Bill Wendling	be9ec3f	2008-11-26 19:07:40 +0000	[diff] [blame]	1060
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1061	<dt><tt>readnone</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1062	<dd>This attribute indicates that the function computes its result (or decides
				1063	to unwind an exception) based strictly on its arguments, without
				1064	dereferencing any pointer arguments or otherwise accessing any mutable
				1065	state (e.g. memory, control registers, etc) visible to caller functions.
				1066	It does not write through any pointer arguments
				1067	(including <tt><a href="#byval">byval</a></tt> arguments) and never
				1068	changes any state visible to callers. This means that it cannot unwind
				1069	exceptions by calling the <tt>C++</tt> exception throwing methods, but
				1070	could use the <tt>unwind</tt> instruction.</dd>
Devang Patel	a2f9f41	2009-06-12 19:45:19 +0000	[diff] [blame]	1071
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1072	<dt><tt><a name="readonly">readonly</a></tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1073	<dd>This attribute indicates that the function does not write through any
				1074	pointer arguments (including <tt><a href="#byval">byval</a></tt>
				1075	arguments) or otherwise modify any state (e.g. memory, control registers,
				1076	etc) visible to caller functions. It may dereference pointer arguments
				1077	and read state that may be set in the caller. A readonly function always
				1078	returns the same value (or unwinds an exception identically) when called
				1079	with the same set of arguments and global state. It cannot unwind an
				1080	exception by calling the <tt>C++</tt> exception throwing methods, but may
				1081	use the <tt>unwind</tt> instruction.</dd>
Anton Korobeynikov	edd7d11	2009-07-17 18:07:26 +0000	[diff] [blame]	1082
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1083	<dt><tt><a name="ssp">ssp</a></tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1084	<dd>This attribute indicates that the function should emit a stack smashing
				1085	protector. It is in the form of a "canary"—a random value placed on
				1086	the stack before the local variables that's checked upon return from the
				1087	function to see if it has been overwritten. A heuristic is used to
				1088	determine if a function needs stack protectors or not.<br>
				1089	<br>
				1090	If a function that has an <tt>ssp</tt> attribute is inlined into a
				1091	function that doesn't have an <tt>ssp</tt> attribute, then the resulting
				1092	function will have an <tt>ssp</tt> attribute.</dd>
				1093
				1094	<dt><tt>sspreq</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1095	<dd>This attribute indicates that the function should <em>always</em> emit a
				1096	stack smashing protector. This overrides
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1097	the <tt><a href="#ssp">ssp</a></tt> function attribute.<br>
				1098	<br>
				1099	If a function that has an <tt>sspreq</tt> attribute is inlined into a
				1100	function that doesn't have an <tt>sspreq</tt> attribute or which has
				1101	an <tt>ssp</tt> attribute, then the resulting function will have
				1102	an <tt>sspreq</tt> attribute.</dd>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1103
				1104	<dt><tt>noredzone</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1105	<dd>This attribute indicates that the code generator should not use a red
				1106	zone, even if the target-specific ABI normally permits it.</dd>
				1107
				1108	<dt><tt>noimplicitfloat</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1109	<dd>This attributes disables implicit floating point instructions.</dd>
				1110
				1111	<dt><tt>naked</tt></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1112	<dd>This attribute disables prologue / epilogue emission for the function.
				1113	This can have very system-specific consequences.</dd>
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1114	</dl>
				1115
Devang Patel	d468f1c	2008-09-04 23:05:13 +0000	[diff] [blame]	1116	</div>
				1117
				1118	<!-- ======================================================================= -->
				1119	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1120	<a name="moduleasm">Module-Level Inline Assembly</a>
				1121	</div>
				1122
				1123	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1124
				1125	<p>Modules may contain "module-level inline asm" blocks, which corresponds to
				1126	the GCC "file scope inline asm" blocks. These blocks are internally
				1127	concatenated by LLVM and treated as a single unit, but may be separated in
				1128	the <tt>.ll</tt> file if desired. The syntax is very simple:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1129
				1130	<div class="doc_code">
				1131	<pre>
				1132	module asm "inline asm code goes here"
				1133	module asm "more can go here"
				1134	</pre>
				1135	</div>
				1136
				1137	<p>The strings can contain any character by escaping non-printable characters.
				1138	The escape sequence used is simply "\xx" where "xx" is the two digit hex code
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1139	for the number.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1140
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1141	<p>The inline asm code is simply printed to the machine code .s file when
				1142	assembly code is generated.</p>
				1143
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1144	</div>
				1145
				1146	<!-- ======================================================================= -->
				1147	<div class="doc_subsection">
				1148	<a name="datalayout">Data Layout</a>
				1149	</div>
				1150
				1151	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1152
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1153	<p>A module may specify a target specific data layout string that specifies how
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1154	data is to be laid out in memory. The syntax for the data layout is
				1155	simply:</p>
				1156
				1157	<div class="doc_code">
				1158	<pre>
				1159	target datalayout = "<i>layout specification</i>"
				1160	</pre>
				1161	</div>
				1162
				1163	<p>The <i>layout specification</i> consists of a list of specifications
				1164	separated by the minus sign character ('-'). Each specification starts with
				1165	a letter and may include other information after the letter to define some
				1166	aspect of the data layout. The specifications accepted are as follows:</p>
				1167
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1168	<dl>
				1169	<dt><tt>E</tt></dt>
				1170	<dd>Specifies that the target lays out data in big-endian form. That is, the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1171	bits with the most significance have the lowest address location.</dd>
				1172
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1173	<dt><tt>e</tt></dt>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1174	<dd>Specifies that the target lays out data in little-endian form. That is,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1175	the bits with the least significance have the lowest address
				1176	location.</dd>
				1177
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1178	<dt><tt>p:<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1179	<dd>This specifies the <i>size</i> of a pointer and its <i>abi</i> and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1180	<i>preferred</i> alignments. All sizes are in bits. Specifying
				1181	the <i>pref</i> alignment is optional. If omitted, the
				1182	preceding <tt>:</tt> should be omitted too.</dd>
				1183
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1184	<dt><tt>i<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1185	<dd>This specifies the alignment for an integer type of a given bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1186	<i>size</i>. The value of <i>size</i> must be in the range [1,2^23).</dd>
				1187
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1188	<dt><tt>v<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1189	<dd>This specifies the alignment for a vector type of a given bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1190	<i>size</i>.</dd>
				1191
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1192	<dt><tt>f<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1193	<dd>This specifies the alignment for a floating point type of a given bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1194	<i>size</i>. The value of <i>size</i> must be either 32 (float) or 64
				1195	(double).</dd>
				1196
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1197	<dt><tt>a<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1198	<dd>This specifies the alignment for an aggregate type of a given bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1199	<i>size</i>.</dd>
				1200
Daniel Dunbar	d88a97b	2009-06-08 22:17:53 +0000	[diff] [blame]	1201	<dt><tt>s<i>size</i>:<i>abi</i>:<i>pref</i></tt></dt>
				1202	<dd>This specifies the alignment for a stack object of a given bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1203	<i>size</i>.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1204	</dl>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1205
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1206	<p>When constructing the data layout for a given target, LLVM starts with a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1207	default set of specifications which are then (possibly) overriden by the
				1208	specifications in the <tt>datalayout</tt> keyword. The default specifications
				1209	are given in this list:</p>
				1210
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1211	<ul>
				1212	<li><tt>E</tt> - big endian</li>
				1213	<li><tt>p:32:64:64</tt> - 32-bit pointers with 64-bit alignment</li>
				1214	<li><tt>i1:8:8</tt> - i1 is 8-bit (byte) aligned</li>
				1215	<li><tt>i8:8:8</tt> - i8 is 8-bit (byte) aligned</li>
				1216	<li><tt>i16:16:16</tt> - i16 is 16-bit aligned</li>
				1217	<li><tt>i32:32:32</tt> - i32 is 32-bit aligned</li>
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	1218	<li><tt>i64:32:64</tt> - i64 has ABI alignment of 32-bits but preferred
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1219	alignment of 64-bits</li>
				1220	<li><tt>f32:32:32</tt> - float is 32-bit aligned</li>
				1221	<li><tt>f64:64:64</tt> - double is 64-bit aligned</li>
				1222	<li><tt>v64:64:64</tt> - 64-bit vector is 64-bit aligned</li>
				1223	<li><tt>v128:128:128</tt> - 128-bit vector is 128-bit aligned</li>
				1224	<li><tt>a0:0:1</tt> - aggregates are 8-bit aligned</li>
Daniel Dunbar	d88a97b	2009-06-08 22:17:53 +0000	[diff] [blame]	1225	<li><tt>s0:64:64</tt> - stack objects are 64-bit aligned</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1226	</ul>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1227
				1228	<p>When LLVM is determining the alignment for a given type, it uses the
				1229	following rules:</p>
				1230
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1231	<ol>
				1232	<li>If the type sought is an exact match for one of the specifications, that
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1233	specification is used.</li>
				1234
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1235	<li>If no match is found, and the type sought is an integer type, then the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1236	smallest integer type that is larger than the bitwidth of the sought type
				1237	is used. If none of the specifications are larger than the bitwidth then
				1238	the the largest integer type is used. For example, given the default
				1239	specifications above, the i7 type will use the alignment of i8 (next
				1240	largest) while both i65 and i256 will use the alignment of i64 (largest
				1241	specified).</li>
				1242
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1243	<li>If no match is found, and the type sought is a vector type, then the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1244	largest vector type that is smaller than the sought vector type will be
				1245	used as a fall back. This happens because <128 x double> can be
				1246	implemented in terms of 64 <2 x double>, for example.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1247	</ol>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1248
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1249	</div>
				1250
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	1251	<!-- ======================================================================= -->
				1252	<div class="doc_subsection">
				1253	<a name="pointeraliasing">Pointer Aliasing Rules</a>
				1254	</div>
				1255
				1256	<div class="doc_text">
				1257
Andreas Bolka	11fbf43	2009-07-29 00:02:05 +0000	[diff] [blame]	1258	<p>Any memory access must be done through a pointer value associated
Andreas Bolka	23bece4	2009-07-27 20:37:10 +0000	[diff] [blame]	1259	with an address range of the memory access, otherwise the behavior
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	1260	is undefined. Pointer values are associated with address ranges
				1261	according to the following rules:</p>
				1262
				1263	<ul>
Andreas Bolka	11fbf43	2009-07-29 00:02:05 +0000	[diff] [blame]	1264	<li>A pointer value formed from a
				1265	<tt><a href="#i_getelementptr">getelementptr</a></tt> instruction
				1266	is associated with the addresses associated with the first operand
				1267	of the <tt>getelementptr</tt>.</li>
				1268	<li>An address of a global variable is associated with the address
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	1269	range of the variable's storage.</li>
				1270	<li>The result value of an allocation instruction is associated with
				1271	the address range of the allocated storage.</li>
				1272	<li>A null pointer in the default address-space is associated with
Andreas Bolka	11fbf43	2009-07-29 00:02:05 +0000	[diff] [blame]	1273	no address.</li>
				1274	<li>A pointer value formed by an
				1275	<tt><a href="#i_inttoptr">inttoptr</a></tt> is associated with all
				1276	address ranges of all pointer values that contribute (directly or
				1277	indirectly) to the computation of the pointer's value.</li>
				1278	<li>The result value of a
				1279	<tt><a href="#i_bitcast">bitcast</a></tt> is associated with all
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	1280	addresses associated with the operand of the <tt>bitcast</tt>.</li>
				1281	<li>An integer constant other than zero or a pointer value returned
				1282	from a function not defined within LLVM may be associated with address
				1283	ranges allocated through mechanisms other than those provided by
Andreas Bolka	11fbf43	2009-07-29 00:02:05 +0000	[diff] [blame]	1284	LLVM. Such ranges shall not overlap with any ranges of addresses
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	1285	allocated by mechanisms provided by LLVM.</li>
				1286	</ul>
				1287
				1288	<p>LLVM IR does not associate types with memory. The result type of a
Andreas Bolka	11fbf43	2009-07-29 00:02:05 +0000	[diff] [blame]	1289	<tt><a href="#i_load">load</a></tt> merely indicates the size and
				1290	alignment of the memory from which to load, as well as the
				1291	interpretation of the value. The first operand of a
				1292	<tt><a href="#i_store">store</a></tt> similarly only indicates the size
				1293	and alignment of the store.</p>
Dan Gohman	27b4701	2009-07-27 18:07:55 +0000	[diff] [blame]	1294
				1295	<p>Consequently, type-based alias analysis, aka TBAA, aka
				1296	<tt>-fstrict-aliasing</tt>, is not applicable to general unadorned
				1297	LLVM IR. <a href="#metadata">Metadata</a> may be used to encode
				1298	additional information which specialized optimization passes may use
				1299	to implement type-based alias analysis.</p>
				1300
				1301	</div>
				1302
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1303	<!-- *********************************************************************** -->
				1304	<div class="doc_section"> <a name="typesystem">Type System</a> </div>
				1305	<!-- *********************************************************************** -->
				1306
				1307	<div class="doc_text">
				1308
				1309	<p>The LLVM type system is one of the most important features of the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1310	intermediate representation. Being typed enables a number of optimizations
				1311	to be performed on the intermediate representation directly, without having
				1312	to do extra analyses on the side before the transformation. A strong type
				1313	system makes it easier to read the generated code and enables novel analyses
				1314	and transformations that are not feasible to perform on normal three address
				1315	code representations.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1316
				1317	</div>
				1318
				1319	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1320	<div class="doc_subsection"> <a name="t_classifications">Type
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1321	Classifications</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1322
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1323	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1324
				1325	<p>The types fall into a few useful classifications:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1326
				1327	<table border="1" cellspacing="0" cellpadding="4">
				1328	<tbody>
				1329	<tr><th>Classification</th><th>Types</th></tr>
				1330	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1331	<td><a href="#t_integer">integer</a></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1332	<td><tt>i1, i2, i3, ... i8, ... i16, ... i32, ... i64, ... </tt></td>
				1333	</tr>
				1334	<tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1335	<td><a href="#t_floating">floating point</a></td>
				1336	<td><tt>float, double, x86_fp80, fp128, ppc_fp128</tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1337	</tr>
				1338	<tr>
				1339	<td><a name="t_firstclass">first class</a></td>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1340	<td><a href="#t_integer">integer</a>,
				1341	<a href="#t_floating">floating point</a>,
				1342	<a href="#t_pointer">pointer</a>,
Dan Gohman	f6237db	2008-06-18 18:42:13 +0000	[diff] [blame]	1343	<a href="#t_vector">vector</a>,
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	1344	<a href="#t_struct">structure</a>,
				1345	<a href="#t_array">array</a>,
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1346	<a href="#t_label">label</a>,
				1347	<a href="#t_metadata">metadata</a>.
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1348	</td>
				1349	</tr>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1350	<tr>
				1351	<td><a href="#t_primitive">primitive</a></td>
				1352	<td><a href="#t_label">label</a>,
				1353	<a href="#t_void">void</a>,
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1354	<a href="#t_floating">floating point</a>,
				1355	<a href="#t_metadata">metadata</a>.</td>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1356	</tr>
				1357	<tr>
				1358	<td><a href="#t_derived">derived</a></td>
				1359	<td><a href="#t_integer">integer</a>,
				1360	<a href="#t_array">array</a>,
				1361	<a href="#t_function">function</a>,
				1362	<a href="#t_pointer">pointer</a>,
				1363	<a href="#t_struct">structure</a>,
				1364	<a href="#t_pstruct">packed structure</a>,
				1365	<a href="#t_vector">vector</a>,
				1366	<a href="#t_opaque">opaque</a>.
Dan Gohman	032ba85	2008-10-14 16:32:04 +0000	[diff] [blame]	1367	</td>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1368	</tr>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1369	</tbody>
				1370	</table>
				1371
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1372	<p>The <a href="#t_firstclass">first class</a> types are perhaps the most
				1373	important. Values of these types are the only ones which can be produced by
				1374	instructions, passed as arguments, or used as operands to instructions.</p>
				1375
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1376	</div>
				1377
				1378	<!-- ======================================================================= -->
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1379	<div class="doc_subsection"> <a name="t_primitive">Primitive Types</a> </div>
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1380
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1381	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1382
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1383	<p>The primitive types are the fundamental building blocks of the LLVM
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1384	system.</p>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1385
Chris Lattner	8643761	2008-01-04 04:34:14 +0000	[diff] [blame]	1386	</div>
				1387
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1388	<!-- _______________________________________________________________________ -->
				1389	<div class="doc_subsubsection"> <a name="t_floating">Floating Point Types</a> </div>
				1390
				1391	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1392
				1393	<table>
				1394	<tbody>
				1395	<tr><th>Type</th><th>Description</th></tr>
				1396	<tr><td><tt>float</tt></td><td>32-bit floating point value</td></tr>
				1397	<tr><td><tt>double</tt></td><td>64-bit floating point value</td></tr>
				1398	<tr><td><tt>fp128</tt></td><td>128-bit floating point value (112-bit mantissa)</td></tr>
				1399	<tr><td><tt>x86_fp80</tt></td><td>80-bit floating point value (X87)</td></tr>
				1400	<tr><td><tt>ppc_fp128</tt></td><td>128-bit floating point value (two 64-bits)</td></tr>
				1401	</tbody>
				1402	</table>
				1403
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1404	</div>
				1405
				1406	<!-- _______________________________________________________________________ -->
				1407	<div class="doc_subsubsection"> <a name="t_void">Void Type</a> </div>
				1408
				1409	<div class="doc_text">
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1410
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1411	<h5>Overview:</h5>
				1412	<p>The void type does not represent any value and has no size.</p>
				1413
				1414	<h5>Syntax:</h5>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1415	<pre>
				1416	void
				1417	</pre>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1418
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1419	</div>
				1420
				1421	<!-- _______________________________________________________________________ -->
				1422	<div class="doc_subsubsection"> <a name="t_label">Label Type</a> </div>
				1423
				1424	<div class="doc_text">
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1425
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1426	<h5>Overview:</h5>
				1427	<p>The label type represents code labels.</p>
				1428
				1429	<h5>Syntax:</h5>
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1430	<pre>
				1431	label
				1432	</pre>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1433
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1434	</div>
				1435
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1436	<!-- _______________________________________________________________________ -->
				1437	<div class="doc_subsubsection"> <a name="t_metadata">Metadata Type</a> </div>
				1438
				1439	<div class="doc_text">
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1440
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1441	<h5>Overview:</h5>
				1442	<p>The metadata type represents embedded metadata. The only derived type that
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1443	may contain metadata is <tt>metadata*</tt> or a function type that returns or
				1444	takes metadata typed parameters, but not pointer to metadata types.</p>
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1445
				1446	<h5>Syntax:</h5>
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1447	<pre>
				1448	metadata
				1449	</pre>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1450
Nick Lewycky	29aaef8	2009-05-30 05:06:04 +0000	[diff] [blame]	1451	</div>
				1452
Chris Lattner	488772f	2008-01-04 04:32:38 +0000	[diff] [blame]	1453
				1454	<!-- ======================================================================= -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1455	<div class="doc_subsection"> <a name="t_derived">Derived Types</a> </div>
				1456
				1457	<div class="doc_text">
				1458
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1459	<p>The real power in LLVM comes from the derived types in the system. This is
				1460	what allows a programmer to represent arrays, functions, pointers, and other
				1461	useful types. Note that these derived types may be recursive: For example,
				1462	it is possible to have a two dimensional array.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1463
				1464	</div>
				1465
				1466	<!-- _______________________________________________________________________ -->
				1467	<div class="doc_subsubsection"> <a name="t_integer">Integer Type</a> </div>
				1468
				1469	<div class="doc_text">
				1470
				1471	<h5>Overview:</h5>
				1472	<p>The integer type is a very simple derived type that simply specifies an
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1473	arbitrary bit width for the integer type desired. Any bit width from 1 bit to
				1474	2^23-1 (about 8 million) can be specified.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1475
				1476	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1477	<pre>
				1478	iN
				1479	</pre>
				1480
				1481	<p>The number of bits the integer will occupy is specified by the <tt>N</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1482	value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1483
				1484	<h5>Examples:</h5>
				1485	<table class="layout">
Nick Lewycky	39382d6	2009-05-24 02:46:06 +0000	[diff] [blame]	1486	<tr class="layout">
				1487	<td class="left"><tt>i1</tt></td>
				1488	<td class="left">a single-bit integer.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1489	</tr>
Nick Lewycky	39382d6	2009-05-24 02:46:06 +0000	[diff] [blame]	1490	<tr class="layout">
				1491	<td class="left"><tt>i32</tt></td>
				1492	<td class="left">a 32-bit integer.</td>
				1493	</tr>
				1494	<tr class="layout">
				1495	<td class="left"><tt>i1942652</tt></td>
				1496	<td class="left">a really big integer of over 1 million bits.</td>
				1497	</tr>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1498	</table>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1499
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1500	<p>Note that the code generator does not yet support large integer types to be
				1501	used as function return types. The specific limit on how large a return type
				1502	the code generator can currently handle is target-dependent; currently it's
				1503	often 64 bits for 32-bit targets and 128 bits for 64-bit targets.</p>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1504
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1505	</div>
				1506
				1507	<!-- _______________________________________________________________________ -->
				1508	<div class="doc_subsubsection"> <a name="t_array">Array Type</a> </div>
				1509
				1510	<div class="doc_text">
				1511
				1512	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1513	<p>The array type is a very simple derived type that arranges elements
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1514	sequentially in memory. The array type requires a size (number of elements)
				1515	and an underlying data type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1516
				1517	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1518	<pre>
				1519	[<# elements> x <elementtype>]
				1520	</pre>
				1521
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1522	<p>The number of elements is a constant integer value; <tt>elementtype</tt> may
				1523	be any type with a size.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1524
				1525	<h5>Examples:</h5>
				1526	<table class="layout">
				1527	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1528	<td class="left"><tt>[40 x i32]</tt></td>
				1529	<td class="left">Array of 40 32-bit integer values.</td>
				1530	</tr>
				1531	<tr class="layout">
				1532	<td class="left"><tt>[41 x i32]</tt></td>
				1533	<td class="left">Array of 41 32-bit integer values.</td>
				1534	</tr>
				1535	<tr class="layout">
				1536	<td class="left"><tt>[4 x i8]</tt></td>
				1537	<td class="left">Array of 4 8-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1538	</tr>
				1539	</table>
				1540	<p>Here are some examples of multidimensional arrays:</p>
				1541	<table class="layout">
				1542	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1543	<td class="left"><tt>[3 x [4 x i32]]</tt></td>
				1544	<td class="left">3x4 array of 32-bit integer values.</td>
				1545	</tr>
				1546	<tr class="layout">
				1547	<td class="left"><tt>[12 x [10 x float]]</tt></td>
				1548	<td class="left">12x10 array of single precision floating point values.</td>
				1549	</tr>
				1550	<tr class="layout">
				1551	<td class="left"><tt>[2 x [3 x [4 x i16]]]</tt></td>
				1552	<td class="left">2x3x4 array of 16-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1553	</tr>
				1554	</table>
				1555
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1556	<p>Note that 'variable sized arrays' can be implemented in LLVM with a zero
				1557	length array. Normally, accesses past the end of an array are undefined in
				1558	LLVM (e.g. it is illegal to access the 5th element of a 3 element array). As
				1559	a special case, however, zero length arrays are recognized to be variable
				1560	length. This allows implementation of 'pascal style arrays' with the LLVM
				1561	type "<tt>{ i32, [0 x float]}</tt>", for example.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1562
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1563	<p>Note that the code generator does not yet support large aggregate types to be
				1564	used as function return types. The specific limit on how large an aggregate
				1565	return type the code generator can currently handle is target-dependent, and
				1566	also dependent on the aggregate element types.</p>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1567
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1568	</div>
				1569
				1570	<!-- _______________________________________________________________________ -->
				1571	<div class="doc_subsubsection"> <a name="t_function">Function Type</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1572
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1573	<div class="doc_text">
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1574
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1575	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1576	<p>The function type can be thought of as a function signature. It consists of
				1577	a return type and a list of formal parameter types. The return type of a
				1578	function type is a scalar type, a void type, or a struct type. If the return
				1579	type is a struct type then all struct elements must be of first class types,
				1580	and the struct must have at least one element.</p>
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	1581
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1582	<h5>Syntax:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1583	<pre>
				1584	<returntype list> (<parameter list>)
				1585	</pre>
				1586
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1587	<p>...where '<tt><parameter list></tt>' is a comma-separated list of type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1588	specifiers. Optionally, the parameter list may include a type <tt>...</tt>,
				1589	which indicates that the function takes a variable number of arguments.
				1590	Variable argument functions can access their arguments with
				1591	the <a href="#int_varargs">variable argument handling intrinsic</a>
				1592	functions. '<tt><returntype list></tt>' is a comma-separated list of
				1593	<a href="#t_firstclass">first class</a> type specifiers.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	1594
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1595	<h5>Examples:</h5>
				1596	<table class="layout">
				1597	<tr class="layout">
				1598	<td class="left"><tt>i32 (i32)</tt></td>
				1599	<td class="left">function taking an <tt>i32</tt>, returning an <tt>i32</tt>
				1600	</td>
				1601	</tr><tr class="layout">
Reid Spencer	f234bed	2007-07-19 23:13:04 +0000	[diff] [blame]	1602	<td class="left"><tt>float (i16 signext, i32 )
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1603	</tt></td>
				1604	<td class="left"><a href="#t_pointer">Pointer</a> to a function that takes
				1605	an <tt>i16</tt> that should be sign extended and a
				1606	<a href="#t_pointer">pointer</a> to <tt>i32</tt>, returning
				1607	<tt>float</tt>.
				1608	</td>
				1609	</tr><tr class="layout">
				1610	<td class="left"><tt>i32 (i8*, ...)</tt></td>
				1611	<td class="left">A vararg function that takes at least one
				1612	<a href="#t_pointer">pointer</a> to <tt>i8 </tt> (char in C),
				1613	which returns an integer. This is the signature for <tt>printf</tt> in
				1614	LLVM.
				1615	</td>
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1616	</tr><tr class="layout">
				1617	<td class="left"><tt>{i32, i32} (i32)</tt></td>
Misha Brukman	afc88b0	2008-11-27 06:41:20 +0000	[diff] [blame]	1618	<td class="left">A function taking an <tt>i32</tt>, returning two
				1619	<tt>i32</tt> values as an aggregate of type <tt>{ i32, i32 }</tt>
Devang Patel	d4ba41d	2008-03-24 05:35:41 +0000	[diff] [blame]	1620	</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1621	</tr>
				1622	</table>
				1623
				1624	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1625
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1626	<!-- _______________________________________________________________________ -->
				1627	<div class="doc_subsubsection"> <a name="t_struct">Structure Type</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1628
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1629	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1630
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1631	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1632	<p>The structure type is used to represent a collection of data members together
				1633	in memory. The packing of the field types is defined to match the ABI of the
				1634	underlying processor. The elements of a structure may be any type that has a
				1635	size.</p>
				1636
				1637	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
				1638	'<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
				1639	the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
				1640
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1641	<h5>Syntax:</h5>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1642	<pre>
				1643	{ <type list> }
				1644	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1645
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1646	<h5>Examples:</h5>
				1647	<table class="layout">
				1648	<tr class="layout">
				1649	<td class="left"><tt>{ i32, i32, i32 }</tt></td>
				1650	<td class="left">A triple of three <tt>i32</tt> values</td>
				1651	</tr><tr class="layout">
				1652	<td class="left"><tt>{ float, i32 (i32) * }</tt></td>
				1653	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1654	second element is a <a href="#t_pointer">pointer</a> to a
				1655	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1656	an <tt>i32</tt>.</td>
				1657	</tr>
				1658	</table>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1659
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1660	<p>Note that the code generator does not yet support large aggregate types to be
				1661	used as function return types. The specific limit on how large an aggregate
				1662	return type the code generator can currently handle is target-dependent, and
				1663	also dependent on the aggregate element types.</p>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1664
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1665	</div>
				1666
				1667	<!-- _______________________________________________________________________ -->
				1668	<div class="doc_subsubsection"> <a name="t_pstruct">Packed Structure Type</a>
				1669	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1670
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1671	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1672
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1673	<h5>Overview:</h5>
				1674	<p>The packed structure type is used to represent a collection of data members
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1675	together in memory. There is no padding between fields. Further, the
				1676	alignment of a packed structure is 1 byte. The elements of a packed
				1677	structure may be any type that has a size.</p>
				1678
				1679	<p>Structures are accessed using '<tt><a href="#i_load">load</a></tt> and
				1680	'<tt><a href="#i_store">store</a></tt>' by getting a pointer to a field with
				1681	the '<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
				1682
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1683	<h5>Syntax:</h5>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1684	<pre>
				1685	< { <type list> } >
				1686	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1687
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1688	<h5>Examples:</h5>
				1689	<table class="layout">
				1690	<tr class="layout">
				1691	<td class="left"><tt>< { i32, i32, i32 } ></tt></td>
				1692	<td class="left">A triple of three <tt>i32</tt> values</td>
				1693	</tr><tr class="layout">
Bill Wendling	74d3eac	2008-09-07 10:26:33 +0000	[diff] [blame]	1694	<td class="left">
				1695	<tt>< { float, i32 (i32)* } ></tt></td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1696	<td class="left">A pair, where the first element is a <tt>float</tt> and the
				1697	second element is a <a href="#t_pointer">pointer</a> to a
				1698	<a href="#t_function">function</a> that takes an <tt>i32</tt>, returning
				1699	an <tt>i32</tt>.</td>
				1700	</tr>
				1701	</table>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1702
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1703	</div>
				1704
				1705	<!-- _______________________________________________________________________ -->
				1706	<div class="doc_subsubsection"> <a name="t_pointer">Pointer Type</a> </div>
Chris Lattner	96edbd3	2009-02-08 19:53:29 +0000	[diff] [blame]	1707
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1708	<div class="doc_text">
				1709
				1710	<h5>Overview:</h5>
				1711	<p>As in many languages, the pointer type represents a pointer or reference to
				1712	another object, which must live in memory. Pointer types may have an optional
				1713	address space attribute defining the target-specific numbered address space
				1714	where the pointed-to object resides. The default address space is zero.</p>
				1715
				1716	<p>Note that LLVM does not permit pointers to void (<tt>void*</tt>) nor does it
				1717	permit pointers to labels (<tt>label</tt>). Use <tt>i8</tt> instead.</p>
Chris Lattner	96edbd3	2009-02-08 19:53:29 +0000	[diff] [blame]	1718
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1719	<h5>Syntax:</h5>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	1720	<pre>
				1721	<type> *
				1722	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1723
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1724	<h5>Examples:</h5>
				1725	<table class="layout">
				1726	<tr class="layout">
Dan Gohman	0185238	2009-01-04 23:44:43 +0000	[diff] [blame]	1727	<td class="left"><tt>[4 x i32]*</tt></td>
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1728	<td class="left">A <a href="#t_pointer">pointer</a> to <a
				1729	href="#t_array">array</a> of four <tt>i32</tt> values.</td>
				1730	</tr>
				1731	<tr class="layout">
				1732	<td class="left"><tt>i32 (i32 ) </tt></td>
				1733	<td class="left"> A <a href="#t_pointer">pointer</a> to a <a
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1734	href="#t_function">function</a> that takes an <tt>i32*</tt>, returning an
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1735	<tt>i32</tt>.</td>
				1736	</tr>
				1737	<tr class="layout">
				1738	<td class="left"><tt>i32 addrspace(5)*</tt></td>
				1739	<td class="left">A <a href="#t_pointer">pointer</a> to an <tt>i32</tt> value
				1740	that resides in address space #5.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1741	</tr>
				1742	</table>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1743
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1744	</div>
				1745
				1746	<!-- _______________________________________________________________________ -->
				1747	<div class="doc_subsubsection"> <a name="t_vector">Vector Type</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1748
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1749	<div class="doc_text">
				1750
				1751	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1752	<p>A vector type is a simple derived type that represents a vector of elements.
				1753	Vector types are used when multiple primitive data are operated in parallel
				1754	using a single instruction (SIMD). A vector type requires a size (number of
				1755	elements) and an underlying primitive data type. Vectors must have a power
				1756	of two length (1, 2, 4, 8, 16 ...). Vector types are considered
				1757	<a href="#t_firstclass">first class</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1758
				1759	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1760	<pre>
				1761	< <# elements> x <elementtype> >
				1762	</pre>
				1763
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1764	<p>The number of elements is a constant integer value; elementtype may be any
				1765	integer or floating point type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1766
				1767	<h5>Examples:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1768	<table class="layout">
				1769	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1770	<td class="left"><tt><4 x i32></tt></td>
				1771	<td class="left">Vector of 4 32-bit integer values.</td>
				1772	</tr>
				1773	<tr class="layout">
				1774	<td class="left"><tt><8 x float></tt></td>
				1775	<td class="left">Vector of 8 32-bit floating-point values.</td>
				1776	</tr>
				1777	<tr class="layout">
				1778	<td class="left"><tt><2 x i64></tt></td>
				1779	<td class="left">Vector of 2 64-bit integer values.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1780	</tr>
				1781	</table>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1782
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1783	<p>Note that the code generator does not yet support large vector types to be
				1784	used as function return types. The specific limit on how large a vector
				1785	return type codegen can currently handle is target-dependent; currently it's
				1786	often a few times longer than a hardware vector register.</p>
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	1787
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1788	</div>
				1789
				1790	<!-- _______________________________________________________________________ -->
				1791	<div class="doc_subsubsection"> <a name="t_opaque">Opaque Type</a> </div>
				1792	<div class="doc_text">
				1793
				1794	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1795	<p>Opaque types are used to represent unknown types in the system. This
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1796	corresponds (for example) to the C notion of a forward declared structure
				1797	type. In LLVM, opaque types can eventually be resolved to any type (not just
				1798	a structure type).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1799
				1800	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1801	<pre>
				1802	opaque
				1803	</pre>
				1804
				1805	<h5>Examples:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1806	<table class="layout">
				1807	<tr class="layout">
Chris Lattner	7311d22	2007-12-19 05:04:11 +0000	[diff] [blame]	1808	<td class="left"><tt>opaque</tt></td>
				1809	<td class="left">An opaque type.</td>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1810	</tr>
				1811	</table>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1812
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1813	</div>
				1814
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1815	<!-- ======================================================================= -->
				1816	<div class="doc_subsection">
				1817	<a name="t_uprefs">Type Up-references</a>
				1818	</div>
				1819
				1820	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1821
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1822	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1823	<p>An "up reference" allows you to refer to a lexically enclosing type without
				1824	requiring it to have a name. For instance, a structure declaration may
				1825	contain a pointer to any of the types it is lexically a member of. Example
				1826	of up references (with their equivalent as named type declarations)
				1827	include:</p>
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1828
				1829	<pre>
Chris Lattner	5ad632d	2009-02-09 10:00:56 +0000	[diff] [blame]	1830	{ \2 * } %x = type { %x* }
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1831	{ \2 }* %y = type { %y }*
				1832	\1* %z = type %z*
				1833	</pre>
				1834
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1835	<p>An up reference is needed by the asmprinter for printing out cyclic types
				1836	when there is no declared name for a type in the cycle. Because the
				1837	asmprinter does not want to print out an infinite type string, it needs a
				1838	syntax to handle recursive types that have no names (all names are optional
				1839	in llvm IR).</p>
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1840
				1841	<h5>Syntax:</h5>
				1842	<pre>
				1843	\<level>
				1844	</pre>
				1845
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1846	<p>The level is the count of the lexical type that is being referred to.</p>
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1847
				1848	<h5>Examples:</h5>
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1849	<table class="layout">
				1850	<tr class="layout">
				1851	<td class="left"><tt>\1*</tt></td>
				1852	<td class="left">Self-referential pointer.</td>
				1853	</tr>
				1854	<tr class="layout">
				1855	<td class="left"><tt>{ { \3*, i8 }, i32 }</tt></td>
				1856	<td class="left">Recursive structure where the upref refers to the out-most
				1857	structure.</td>
				1858	</tr>
				1859	</table>
Chris Lattner	515195a	2009-02-02 07:32:36 +0000	[diff] [blame]	1860
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1861	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1862
				1863	<!-- *********************************************************************** -->
				1864	<div class="doc_section"> <a name="constants">Constants</a> </div>
				1865	<!-- *********************************************************************** -->
				1866
				1867	<div class="doc_text">
				1868
				1869	<p>LLVM has several different basic types of constants. This section describes
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1870	them all and their syntax.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1871
				1872	</div>
				1873
				1874	<!-- ======================================================================= -->
				1875	<div class="doc_subsection"><a name="simpleconstants">Simple Constants</a></div>
				1876
				1877	<div class="doc_text">
				1878
				1879	<dl>
				1880	<dt><b>Boolean constants</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1881	<dd>The two strings '<tt>true</tt>' and '<tt>false</tt>' are both valid
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1882	constants of the <tt><a href="#t_primitive">i1</a></tt> type.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1883
				1884	<dt><b>Integer constants</b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1885	<dd>Standard integers (such as '4') are constants of
				1886	the <a href="#t_integer">integer</a> type. Negative numbers may be used
				1887	with integer types.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1888
				1889	<dt><b>Floating point constants</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1890	<dd>Floating point constants use standard decimal notation (e.g. 123.421),
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1891	exponential notation (e.g. 1.23421e+2), or a more precise hexadecimal
				1892	notation (see below). The assembler requires the exact decimal value of a
				1893	floating-point constant. For example, the assembler accepts 1.25 but
				1894	rejects 1.3 because 1.3 is a repeating decimal in binary. Floating point
				1895	constants must have a <a href="#t_floating">floating point</a> type. </dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1896
				1897	<dt><b>Null pointer constants</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1898	<dd>The identifier '<tt>null</tt>' is recognized as a null pointer constant
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1899	and must be of <a href="#t_pointer">pointer type</a>.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1900	</dl>
				1901
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1902	<p>The one non-intuitive notation for constants is the hexadecimal form of
				1903	floating point constants. For example, the form '<tt>double
				1904	0x432ff973cafa8000</tt>' is equivalent to (but harder to read than)
				1905	'<tt>double 4.5e+15</tt>'. The only time hexadecimal floating point
				1906	constants are required (and the only time that they are generated by the
				1907	disassembler) is when a floating point constant must be emitted but it cannot
				1908	be represented as a decimal floating point number in a reasonable number of
				1909	digits. For example, NaN's, infinities, and other special values are
				1910	represented in their IEEE hexadecimal format so that assembly and disassembly
				1911	do not cause any bits to change in the constants.</p>
				1912
Dale Johannesen	f82a52f	2009-02-11 22:14:51 +0000	[diff] [blame]	1913	<p>When using the hexadecimal form, constants of types float and double are
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1914	represented using the 16-digit form shown above (which matches the IEEE754
				1915	representation for double); float values must, however, be exactly
				1916	representable as IEE754 single precision. Hexadecimal format is always used
				1917	for long double, and there are three forms of long double. The 80-bit format
				1918	used by x86 is represented as <tt>0xK</tt> followed by 20 hexadecimal digits.
				1919	The 128-bit format used by PowerPC (two adjacent doubles) is represented
				1920	by <tt>0xM</tt> followed by 32 hexadecimal digits. The IEEE 128-bit format
				1921	is represented by <tt>0xL</tt> followed by 32 hexadecimal digits; no
				1922	currently supported target uses this format. Long doubles will only work if
				1923	they match the long double format on your target. All hexadecimal formats
				1924	are big-endian (sign bit at the left).</p>
				1925
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1926	</div>
				1927
				1928	<!-- ======================================================================= -->
Chris Lattner	9706385	2009-02-28 18:32:25 +0000	[diff] [blame]	1929	<div class="doc_subsection">
Bill Wendling	1a2630a	2009-07-20 02:32:41 +0000	[diff] [blame]	1930	<a name="aggregateconstants"></a> <!-- old anchor -->
				1931	<a name="complexconstants">Complex Constants</a>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1932	</div>
				1933
				1934	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1935
Chris Lattner	9706385	2009-02-28 18:32:25 +0000	[diff] [blame]	1936	<p>Complex constants are a (potentially recursive) combination of simple
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1937	constants and smaller complex constants.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1938
				1939	<dl>
				1940	<dt><b>Structure constants</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1941	<dd>Structure constants are represented with notation similar to structure
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1942	type definitions (a comma separated list of elements, surrounded by braces
				1943	(<tt>{}</tt>)). For example: "<tt>{ i32 4, float 17.0, i32* @G }</tt>",
				1944	where "<tt>@G</tt>" is declared as "<tt>@G = external global i32</tt>".
				1945	Structure constants must have <a href="#t_struct">structure type</a>, and
				1946	the number and types of elements must match those specified by the
				1947	type.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1948
				1949	<dt><b>Array constants</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1950	<dd>Array constants are represented with notation similar to array type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1951	definitions (a comma separated list of elements, surrounded by square
				1952	brackets (<tt>[]</tt>)). For example: "<tt>[ i32 42, i32 11, i32 74
				1953	]</tt>". Array constants must have <a href="#t_array">array type</a>, and
				1954	the number and types of elements must match those specified by the
				1955	type.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1956
				1957	<dt><b>Vector constants</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1958	<dd>Vector constants are represented with notation similar to vector type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1959	definitions (a comma separated list of elements, surrounded by
				1960	less-than/greater-than's (<tt><></tt>)). For example: "<tt>< i32
				1961	42, i32 11, i32 74, i32 100 ></tt>". Vector constants must
				1962	have <a href="#t_vector">vector type</a>, and the number and types of
				1963	elements must match those specified by the type.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1964
				1965	<dt><b>Zero initialization</b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1966	<dd>The string '<tt>zeroinitializer</tt>' can be used to zero initialize a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1967	value to zero of <em>any</em> type, including scalar and aggregate types.
				1968	This is often used to avoid having to print large zero initializers
				1969	(e.g. for large arrays) and is always exactly equivalent to using explicit
				1970	zero initializers.</dd>
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	1971
				1972	<dt><b>Metadata node</b></dt>
Nick Lewycky	f122c7e	2009-05-30 16:08:30 +0000	[diff] [blame]	1973	<dd>A metadata node is a structure-like constant with
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1974	<a href="#t_metadata">metadata type</a>. For example: "<tt>metadata !{
				1975	i32 0, metadata !"test" }</tt>". Unlike other constants that are meant to
				1976	be interpreted as part of the instruction stream, metadata is a place to
				1977	attach additional information such as debug info.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1978	</dl>
				1979
				1980	</div>
				1981
				1982	<!-- ======================================================================= -->
				1983	<div class="doc_subsection">
				1984	<a name="globalconstants">Global Variable and Function Addresses</a>
				1985	</div>
				1986
				1987	<div class="doc_text">
				1988
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	1989	<p>The addresses of <a href="#globalvars">global variables</a>
				1990	and <a href="#functionstructure">functions</a> are always implicitly valid
				1991	(link-time) constants. These constants are explicitly referenced when
				1992	the <a href="#identifiers">identifier for the global</a> is used and always
				1993	have <a href="#t_pointer">pointer</a> type. For example, the following is a
				1994	legal LLVM file:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	1995
				1996	<div class="doc_code">
				1997	<pre>
				1998	@X = global i32 17
				1999	@Y = global i32 42
				2000	@Z = global [2 x i32] [ i32 @X, i32* @Y ]
				2001	</pre>
				2002	</div>
				2003
				2004	</div>
				2005
				2006	<!-- ======================================================================= -->
				2007	<div class="doc_subsection"><a name="undefvalues">Undefined Values</a></div>
				2008	<div class="doc_text">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2009
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2010	<p>The string '<tt>undef</tt>' is recognized as a type-less constant that has no
				2011	specific value. Undefined values may be of any type and be used anywhere a
				2012	constant is permitted.</p>
				2013
				2014	<p>Undefined values indicate to the compiler that the program is well defined no
				2015	matter what value is used, giving the compiler more freedom to optimize.</p>
				2016
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2017	</div>
				2018
				2019	<!-- ======================================================================= -->
				2020	<div class="doc_subsection"><a name="constantexprs">Constant Expressions</a>
				2021	</div>
				2022
				2023	<div class="doc_text">
				2024
				2025	<p>Constant expressions are used to allow expressions involving other constants
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2026	to be used as constants. Constant expressions may be of
				2027	any <a href="#t_firstclass">first class</a> type and may involve any LLVM
				2028	operation that does not have side effects (e.g. load and call are not
				2029	supported). The following is the syntax for constant expressions:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2030
				2031	<dl>
				2032	<dt><b><tt>trunc ( CST to TYPE )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2033	<dd>Truncate a constant to another type. The bit size of CST must be larger
				2034	than the bit size of TYPE. Both types must be integers.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2035
				2036	<dt><b><tt>zext ( CST to TYPE )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2037	<dd>Zero extend a constant to another type. The bit size of CST must be
				2038	smaller or equal to the bit size of TYPE. Both types must be
				2039	integers.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2040
				2041	<dt><b><tt>sext ( CST to TYPE )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2042	<dd>Sign extend a constant to another type. The bit size of CST must be
				2043	smaller or equal to the bit size of TYPE. Both types must be
				2044	integers.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2045
				2046	<dt><b><tt>fptrunc ( CST to TYPE )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2047	<dd>Truncate a floating point constant to another floating point type. The
				2048	size of CST must be larger than the size of TYPE. Both types must be
				2049	floating point.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2050
				2051	<dt><b><tt>fpext ( CST to TYPE )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2052	<dd>Floating point extend a constant to another type. The size of CST must be
				2053	smaller or equal to the size of TYPE. Both types must be floating
				2054	point.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2055
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	2056	<dt><b><tt>fptoui ( CST to TYPE )</tt></b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2057	<dd>Convert a floating point constant to the corresponding unsigned integer
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2058	constant. TYPE must be a scalar or vector integer type. CST must be of
				2059	scalar or vector floating point type. Both CST and TYPE must be scalars,
				2060	or vectors of the same number of elements. If the value won't fit in the
				2061	integer type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2062
				2063	<dt><b><tt>fptosi ( CST to TYPE )</tt></b></dt>
				2064	<dd>Convert a floating point constant to the corresponding signed integer
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2065	constant. TYPE must be a scalar or vector integer type. CST must be of
				2066	scalar or vector floating point type. Both CST and TYPE must be scalars,
				2067	or vectors of the same number of elements. If the value won't fit in the
				2068	integer type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2069
				2070	<dt><b><tt>uitofp ( CST to TYPE )</tt></b></dt>
				2071	<dd>Convert an unsigned integer constant to the corresponding floating point
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2072	constant. TYPE must be a scalar or vector floating point type. CST must be
				2073	of scalar or vector integer type. Both CST and TYPE must be scalars, or
				2074	vectors of the same number of elements. If the value won't fit in the
				2075	floating point type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2076
				2077	<dt><b><tt>sitofp ( CST to TYPE )</tt></b></dt>
				2078	<dd>Convert a signed integer constant to the corresponding floating point
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2079	constant. TYPE must be a scalar or vector floating point type. CST must be
				2080	of scalar or vector integer type. Both CST and TYPE must be scalars, or
				2081	vectors of the same number of elements. If the value won't fit in the
				2082	floating point type, the results are undefined.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2083
				2084	<dt><b><tt>ptrtoint ( CST to TYPE )</tt></b></dt>
				2085	<dd>Convert a pointer typed constant to the corresponding integer constant
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2086	<tt>TYPE</tt> must be an integer type. <tt>CST</tt> must be of pointer
				2087	type. The <tt>CST</tt> value is zero extended, truncated, or unchanged to
				2088	make it fit in <tt>TYPE</tt>.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2089
				2090	<dt><b><tt>inttoptr ( CST to TYPE )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2091	<dd>Convert a integer constant to a pointer constant. TYPE must be a pointer
				2092	type. CST must be of integer type. The CST value is zero extended,
				2093	truncated, or unchanged to make it fit in a pointer size. This one is
				2094	<i>really</i> dangerous!</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2095
				2096	<dt><b><tt>bitcast ( CST to TYPE )</tt></b></dt>
Chris Lattner	557bc5d	2009-02-28 18:27:03 +0000	[diff] [blame]	2097	<dd>Convert a constant, CST, to another TYPE. The constraints of the operands
				2098	are the same as those for the <a href="#i_bitcast">bitcast
				2099	instruction</a>.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2100
				2101	<dt><b><tt>getelementptr ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman	106b2ae	2009-07-27 21:53:46 +0000	[diff] [blame]	2102	<dt><b><tt>getelementptr inbounds ( CSTPTR, IDX0, IDX1, ... )</tt></b></dt>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2103	<dd>Perform the <a href="#i_getelementptr">getelementptr operation</a> on
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2104	constants. As with the <a href="#i_getelementptr">getelementptr</a>
				2105	instruction, the index list may have zero or more indexes, which are
				2106	required to make sense for the type of "CSTPTR".</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2107
				2108	<dt><b><tt>select ( COND, VAL1, VAL2 )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2109	<dd>Perform the <a href="#i_select">select operation</a> on constants.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2110
				2111	<dt><b><tt>icmp COND ( VAL1, VAL2 )</tt></b></dt>
				2112	<dd>Performs the <a href="#i_icmp">icmp operation</a> on constants.</dd>
				2113
				2114	<dt><b><tt>fcmp COND ( VAL1, VAL2 )</tt></b></dt>
				2115	<dd>Performs the <a href="#i_fcmp">fcmp operation</a> on constants.</dd>
				2116
				2117	<dt><b><tt>extractelement ( VAL, IDX )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2118	<dd>Perform the <a href="#i_extractelement">extractelement operation</a> on
				2119	constants.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2120
				2121	<dt><b><tt>insertelement ( VAL, ELT, IDX )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2122	<dd>Perform the <a href="#i_insertelement">insertelement operation</a> on
				2123	constants.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2124
				2125	<dt><b><tt>shufflevector ( VEC1, VEC2, IDXMASK )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2126	<dd>Perform the <a href="#i_shufflevector">shufflevector operation</a> on
				2127	constants.</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2128
				2129	<dt><b><tt>OPCODE ( LHS, RHS )</tt></b></dt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2130	<dd>Perform the specified operation of the LHS and RHS constants. OPCODE may
				2131	be any of the <a href="#binaryops">binary</a>
				2132	or <a href="#bitwiseops">bitwise binary</a> operations. The constraints
				2133	on operands are the same as those for the corresponding instruction
				2134	(e.g. no bitwise operations on floating point values are allowed).</dd>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2135	</dl>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2136
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2137	</div>
				2138
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	2139	<!-- ======================================================================= -->
				2140	<div class="doc_subsection"><a name="metadata">Embedded Metadata</a>
				2141	</div>
				2142
				2143	<div class="doc_text">
				2144
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2145	<p>Embedded metadata provides a way to attach arbitrary data to the instruction
				2146	stream without affecting the behaviour of the program. There are two
				2147	metadata primitives, strings and nodes. All metadata has the
				2148	<tt>metadata</tt> type and is identified in syntax by a preceding exclamation
				2149	point ('<tt>!</tt>').</p>
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	2150
				2151	<p>A metadata string is a string surrounded by double quotes. It can contain
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2152	any character by escaping non-printable characters with "\xx" where "xx" is
				2153	the two digit hex code. For example: "<tt>!"test\00"</tt>".</p>
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	2154
				2155	<p>Metadata nodes are represented with notation similar to structure constants
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2156	(a comma separated list of elements, surrounded by braces and preceeded by an
				2157	exclamation point). For example: "<tt>!{ metadata !"test\00", i32
				2158	10}</tt>".</p>
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	2159
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2160	<p>A metadata node will attempt to track changes to the values it holds. In the
				2161	event that a value is deleted, it will be replaced with a typeless
				2162	"<tt>null</tt>", such as "<tt>metadata !{null, i32 10}</tt>".</p>
Nick Lewycky	117f438	2009-05-10 20:57:05 +0000	[diff] [blame]	2163
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	2164	<p>Optimizations may rely on metadata to provide additional information about
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2165	the program that isn't available in the instructions, or that isn't easily
				2166	computable. Similarly, the code generator may expect a certain metadata
				2167	format to be used to express debugging information.</p>
				2168
Nick Lewycky	4dcf810	2009-04-04 07:22:01 +0000	[diff] [blame]	2169	</div>
				2170
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2171	<!-- *********************************************************************** -->
				2172	<div class="doc_section"> <a name="othervalues">Other Values</a> </div>
				2173	<!-- *********************************************************************** -->
				2174
				2175	<!-- ======================================================================= -->
				2176	<div class="doc_subsection">
				2177	<a name="inlineasm">Inline Assembler Expressions</a>
				2178	</div>
				2179
				2180	<div class="doc_text">
				2181
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2182	<p>LLVM supports inline assembler expressions (as opposed
				2183	to <a href="#moduleasm"> Module-Level Inline Assembly</a>) through the use of
				2184	a special value. This value represents the inline assembler as a string
				2185	(containing the instructions to emit), a list of operand constraints (stored
				2186	as a string), and a flag that indicates whether or not the inline asm
				2187	expression has side effects. An example inline assembler expression is:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2188
				2189	<div class="doc_code">
				2190	<pre>
				2191	i32 (i32) asm "bswap $0", "=r,r"
				2192	</pre>
				2193	</div>
				2194
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2195	<p>Inline assembler expressions may <b>only</b> be used as the callee operand of
				2196	a <a href="#i_call"><tt>call</tt> instruction</a>. Thus, typically we
				2197	have:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2198
				2199	<div class="doc_code">
				2200	<pre>
				2201	%X = call i32 asm "<a href="#int_bswap">bswap</a> $0", "=r,r"(i32 %Y)
				2202	</pre>
				2203	</div>
				2204
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2205	<p>Inline asms with side effects not visible in the constraint list must be
				2206	marked as having side effects. This is done through the use of the
				2207	'<tt>sideeffect</tt>' keyword, like so:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2208
				2209	<div class="doc_code">
				2210	<pre>
				2211	call void asm sideeffect "eieio", ""()
				2212	</pre>
				2213	</div>
				2214
				2215	<p>TODO: The format of the asm and constraints string still need to be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2216	documented here. Constraints on what can be done (e.g. duplication, moving,
				2217	etc need to be documented). This is probably best done by reference to
				2218	another document that covers inline asm from a holistic perspective.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2219
				2220	</div>
				2221
Chris Lattner	75c24e0	2009-07-20 05:55:19 +0000	[diff] [blame]	2222
				2223	<!-- *********************************************************************** -->
				2224	<div class="doc_section">
				2225	<a name="intrinsic_globals">Intrinsic Global Variables</a>
				2226	</div>
				2227	<!-- *********************************************************************** -->
				2228
				2229	<p>LLVM has a number of "magic" global variables that contain data that affect
				2230	code generation or other IR semantics. These are documented here. All globals
Chris Lattner	1e0e0d1	2009-07-20 06:14:25 +0000	[diff] [blame]	2231	of this sort should have a section specified as "<tt>llvm.metadata</tt>". This
				2232	section and all globals that start with "<tt>llvm.</tt>" are reserved for use
				2233	by LLVM.</p>
Chris Lattner	75c24e0	2009-07-20 05:55:19 +0000	[diff] [blame]	2234
				2235	<!-- ======================================================================= -->
				2236	<div class="doc_subsection">
				2237	<a name="intg_used">The '<tt>llvm.used</tt>' Global Variable</a>
				2238	</div>
				2239
				2240	<div class="doc_text">
				2241
				2242	<p>The <tt>@llvm.used</tt> global is an array with i8* element type which has <a
				2243	href="#linkage_appending">appending linkage</a>. This array contains a list of
				2244	pointers to global variables and functions which may optionally have a pointer
				2245	cast formed of bitcast or getelementptr. For example, a legal use of it is:</p>
				2246
				2247	<pre>
				2248	@X = global i8 4
				2249	@Y = global i32 123
				2250
				2251	@llvm.used = appending global [2 x i8*] [
				2252	i8* @X,
				2253	i8* bitcast (i32* @Y to i8*)
				2254	], section "llvm.metadata"
				2255	</pre>
				2256
				2257	<p>If a global variable appears in the <tt>@llvm.used</tt> list, then the
				2258	compiler, assembler, and linker are required to treat the symbol as if there is
				2259	a reference to the global that it cannot see. For example, if a variable has
				2260	internal linkage and no references other than that from the <tt>@llvm.used</tt>
				2261	list, it cannot be deleted. This is commonly used to represent references from
				2262	inline asms and other things the compiler cannot "see", and corresponds to
				2263	"attribute((used))" in GNU C.</p>
				2264
				2265	<p>On some targets, the code generator must emit a directive to the assembler or
				2266	object file to prevent the assembler and linker from molesting the symbol.</p>
				2267
				2268	</div>
				2269
				2270	<!-- ======================================================================= -->
				2271	<div class="doc_subsection">
Chris Lattner	1e0e0d1	2009-07-20 06:14:25 +0000	[diff] [blame]	2272	<a name="intg_compiler_used">The '<tt>llvm.compiler.used</tt>' Global Variable</a>
				2273	</div>
				2274
				2275	<div class="doc_text">
				2276
				2277	<p>The <tt>@llvm.compiler.used</tt> directive is the same as the
				2278	<tt>@llvm.used</tt> directive, except that it only prevents the compiler from
				2279	touching the symbol. On targets that support it, this allows an intelligent
				2280	linker to optimize references to the symbol without being impeded as it would be
				2281	by <tt>@llvm.used</tt>.</p>
				2282
				2283	<p>This is a rare construct that should only be used in rare circumstances, and
				2284	should not be exposed to source languages.</p>
				2285
				2286	</div>
				2287
				2288	<!-- ======================================================================= -->
				2289	<div class="doc_subsection">
Chris Lattner	75c24e0	2009-07-20 05:55:19 +0000	[diff] [blame]	2290	<a name="intg_global_ctors">The '<tt>llvm.global_ctors</tt>' Global Variable</a>
				2291	</div>
				2292
				2293	<div class="doc_text">
				2294
				2295	<p>TODO: Describe this.</p>
				2296
				2297	</div>
				2298
				2299	<!-- ======================================================================= -->
				2300	<div class="doc_subsection">
				2301	<a name="intg_global_dtors">The '<tt>llvm.global_dtors</tt>' Global Variable</a>
				2302	</div>
				2303
				2304	<div class="doc_text">
				2305
				2306	<p>TODO: Describe this.</p>
				2307
				2308	</div>
				2309
				2310
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2311	<!-- *********************************************************************** -->
				2312	<div class="doc_section"> <a name="instref">Instruction Reference</a> </div>
				2313	<!-- *********************************************************************** -->
				2314
				2315	<div class="doc_text">
				2316
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2317	<p>The LLVM instruction set consists of several different classifications of
				2318	instructions: <a href="#terminators">terminator
				2319	instructions</a>, <a href="#binaryops">binary instructions</a>,
				2320	<a href="#bitwiseops">bitwise binary instructions</a>,
				2321	<a href="#memoryops">memory instructions</a>, and
				2322	<a href="#otherops">other instructions</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2323
				2324	</div>
				2325
				2326	<!-- ======================================================================= -->
				2327	<div class="doc_subsection"> <a name="terminators">Terminator
				2328	Instructions</a> </div>
				2329
				2330	<div class="doc_text">
				2331
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2332	<p>As mentioned <a href="#functionstructure">previously</a>, every basic block
				2333	in a program ends with a "Terminator" instruction, which indicates which
				2334	block should be executed after the current block is finished. These
				2335	terminator instructions typically yield a '<tt>void</tt>' value: they produce
				2336	control flow, not values (the one exception being the
				2337	'<a href="#i_invoke"><tt>invoke</tt></a>' instruction).</p>
				2338
				2339	<p>There are six different terminator instructions: the
				2340	'<a href="#i_ret"><tt>ret</tt></a>' instruction, the
				2341	'<a href="#i_br"><tt>br</tt></a>' instruction, the
				2342	'<a href="#i_switch"><tt>switch</tt></a>' instruction, the
				2343	'<a href="#i_invoke"><tt>invoke</tt></a>' instruction, the
				2344	'<a href="#i_unwind"><tt>unwind</tt></a>' instruction, and the
				2345	'<a href="#i_unreachable"><tt>unreachable</tt></a>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2346
				2347	</div>
				2348
				2349	<!-- _______________________________________________________________________ -->
				2350	<div class="doc_subsubsection"> <a name="i_ret">'<tt>ret</tt>'
				2351	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2352
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2353	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2354
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2355	<h5>Syntax:</h5>
Dan Gohman	3e70003	2008-10-04 19:00:07 +0000	[diff] [blame]	2356	<pre>
				2357	ret <type> <value> <i>; Return a value from a non-void function</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2358	ret void <i>; Return from void function</i>
				2359	</pre>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	2360
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2361	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2362	<p>The '<tt>ret</tt>' instruction is used to return control flow (and optionally
				2363	a value) from a function back to the caller.</p>
				2364
				2365	<p>There are two forms of the '<tt>ret</tt>' instruction: one that returns a
				2366	value and then causes control flow, and one that just causes control flow to
				2367	occur.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	2368
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2369	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2370	<p>The '<tt>ret</tt>' instruction optionally accepts a single argument, the
				2371	return value. The type of the return value must be a
				2372	'<a href="#t_firstclass">first class</a>' type.</p>
Dan Gohman	3e70003	2008-10-04 19:00:07 +0000	[diff] [blame]	2373
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2374	<p>A function is not <a href="#wellformed">well formed</a> if it it has a
				2375	non-void return type and contains a '<tt>ret</tt>' instruction with no return
				2376	value or a return value with a type that does not match its type, or if it
				2377	has a void return type and contains a '<tt>ret</tt>' instruction with a
				2378	return value.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	2379
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2380	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2381	<p>When the '<tt>ret</tt>' instruction is executed, control flow returns back to
				2382	the calling function's context. If the caller is a
				2383	"<a href="#i_call"><tt>call</tt></a>" instruction, execution continues at the
				2384	instruction after the call. If the caller was an
				2385	"<a href="#i_invoke"><tt>invoke</tt></a>" instruction, execution continues at
				2386	the beginning of the "normal" destination block. If the instruction returns
				2387	a value, that value shall set the call or invoke instruction's return
				2388	value.</p>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	2389
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2390	<h5>Example:</h5>
Chris Lattner	43030e7	2008-04-23 04:59:35 +0000	[diff] [blame]	2391	<pre>
				2392	ret i32 5 <i>; Return an integer value of 5</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2393	ret void <i>; Return from a void function</i>
Bill Wendling	d163e2d	2009-02-28 22:12:54 +0000	[diff] [blame]	2394	ret { i32, i8 } { i32 4, i8 2 } <i>; Return a struct of values 4 and 2</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2395	</pre>
Dan Gohman	6096719	2009-01-12 23:12:39 +0000	[diff] [blame]	2396
djg	e93155c	2009-01-24 15:58:40 +0000	[diff] [blame]	2397	<p>Note that the code generator does not yet fully support large
				2398	return values. The specific sizes that are currently supported are
				2399	dependent on the target. For integers, on 32-bit targets the limit
				2400	is often 64 bits, and on 64-bit targets the limit is often 128 bits.
				2401	For aggregate types, the current limits are dependent on the element
				2402	types; for example targets are often limited to 2 total integer
				2403	elements and 2 total floating-point elements.</p>
Dan Gohman	6096719	2009-01-12 23:12:39 +0000	[diff] [blame]	2404
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2405	</div>
				2406	<!-- _______________________________________________________________________ -->
				2407	<div class="doc_subsubsection"> <a name="i_br">'<tt>br</tt>' Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2408
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2409	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2410
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2411	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2412	<pre>
				2413	br i1 <cond>, label <iftrue>, label <iffalse><br> br label <dest> <i>; Unconditional branch</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2414	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2415
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2416	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2417	<p>The '<tt>br</tt>' instruction is used to cause control flow to transfer to a
				2418	different basic block in the current function. There are two forms of this
				2419	instruction, corresponding to a conditional branch and an unconditional
				2420	branch.</p>
				2421
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2422	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2423	<p>The conditional branch form of the '<tt>br</tt>' instruction takes a single
				2424	'<tt>i1</tt>' value and two '<tt>label</tt>' values. The unconditional form
				2425	of the '<tt>br</tt>' instruction takes a single '<tt>label</tt>' value as a
				2426	target.</p>
				2427
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2428	<h5>Semantics:</h5>
				2429	<p>Upon execution of a conditional '<tt>br</tt>' instruction, the '<tt>i1</tt>'
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2430	argument is evaluated. If the value is <tt>true</tt>, control flows to the
				2431	'<tt>iftrue</tt>' <tt>label</tt> argument. If "cond" is <tt>false</tt>,
				2432	control flows to the '<tt>iffalse</tt>' <tt>label</tt> argument.</p>
				2433
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2434	<h5>Example:</h5>
Bill Wendling	6ec4061	2009-07-20 02:39:26 +0000	[diff] [blame]	2435	<pre>
				2436	Test:
				2437	%cond = <a href="#i_icmp">icmp</a> eq i32 %a, %b
				2438	br i1 %cond, label %IfEqual, label %IfUnequal
				2439	IfEqual:
				2440	<a href="#i_ret">ret</a> i32 1
				2441	IfUnequal:
				2442	<a href="#i_ret">ret</a> i32 0
				2443	</pre>
				2444
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2445	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2446
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2447	<!-- _______________________________________________________________________ -->
				2448	<div class="doc_subsubsection">
				2449	<a name="i_switch">'<tt>switch</tt>' Instruction</a>
				2450	</div>
				2451
				2452	<div class="doc_text">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2453
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2454	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2455	<pre>
				2456	switch <intty> <value>, label <defaultdest> [ <intty> <val>, label <dest> ... ]
				2457	</pre>
				2458
				2459	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2460	<p>The '<tt>switch</tt>' instruction is used to transfer control flow to one of
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2461	several different places. It is a generalization of the '<tt>br</tt>'
				2462	instruction, allowing a branch to occur to one of many possible
				2463	destinations.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2464
				2465	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2466	<p>The '<tt>switch</tt>' instruction uses three parameters: an integer
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2467	comparison value '<tt>value</tt>', a default '<tt>label</tt>' destination,
				2468	and an array of pairs of comparison value constants and '<tt>label</tt>'s.
				2469	The table is not allowed to contain duplicate constant entries.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2470
				2471	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2472	<p>The <tt>switch</tt> instruction specifies a table of values and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2473	destinations. When the '<tt>switch</tt>' instruction is executed, this table
				2474	is searched for the given value. If the value is found, control flow is
				2475	transfered to the corresponding destination; otherwise, control flow is
				2476	transfered to the default destination.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2477
				2478	<h5>Implementation:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2479	<p>Depending on properties of the target machine and the particular
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2480	<tt>switch</tt> instruction, this instruction may be code generated in
				2481	different ways. For example, it could be generated as a series of chained
				2482	conditional branches or with a lookup table.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2483
				2484	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2485	<pre>
				2486	<i>; Emulate a conditional br instruction</i>
				2487	%Val = <a href="#i_zext">zext</a> i1 %value to i32
Dan Gohman	0185238	2009-01-04 23:44:43 +0000	[diff] [blame]	2488	switch i32 %Val, label %truedest [ i32 0, label %falsedest ]
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2489
				2490	<i>; Emulate an unconditional br instruction</i>
				2491	switch i32 0, label %dest [ ]
				2492
				2493	<i>; Implement a jump table:</i>
Dan Gohman	0185238	2009-01-04 23:44:43 +0000	[diff] [blame]	2494	switch i32 %val, label %otherwise [ i32 0, label %onzero
				2495	i32 1, label %onone
				2496	i32 2, label %ontwo ]
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2497	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2498
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2499	</div>
				2500
				2501	<!-- _______________________________________________________________________ -->
				2502	<div class="doc_subsubsection">
				2503	<a name="i_invoke">'<tt>invoke</tt>' Instruction</a>
				2504	</div>
				2505
				2506	<div class="doc_text">
				2507
				2508	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2509	<pre>
Devang Patel	d0bfcc7	2008-10-07 17:48:33 +0000	[diff] [blame]	2510	<result> = invoke [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] <ptr to function ty> <function ptr val>(<function args>) [<a href="#fnattrs">fn attrs</a>]
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2511	to label <normal label> unwind label <exception label>
				2512	</pre>
				2513
				2514	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2515	<p>The '<tt>invoke</tt>' instruction causes control to transfer to a specified
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2516	function, with the possibility of control flow transfer to either the
				2517	'<tt>normal</tt>' label or the '<tt>exception</tt>' label. If the callee
				2518	function returns with the "<tt><a href="#i_ret">ret</a></tt>" instruction,
				2519	control flow will return to the "normal" label. If the callee (or any
				2520	indirect callees) returns with the "<a href="#i_unwind"><tt>unwind</tt></a>"
				2521	instruction, control is interrupted and continued at the dynamically nearest
				2522	"exception" label.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2523
				2524	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2525	<p>This instruction requires several arguments:</p>
				2526
				2527	<ol>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2528	<li>The optional "cconv" marker indicates which <a href="#callingconv">calling
				2529	convention</a> the call should use. If none is specified, the call
				2530	defaults to using C calling conventions.</li>
Devang Patel	ac2fc27	2008-10-06 18:50:38 +0000	[diff] [blame]	2531
				2532	<li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2533	return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
				2534	'<tt>inreg</tt>' attributes are valid here.</li>
Devang Patel	ac2fc27	2008-10-06 18:50:38 +0000	[diff] [blame]	2535
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2536	<li>'<tt>ptr to function ty</tt>': shall be the signature of the pointer to
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2537	function value being invoked. In most cases, this is a direct function
				2538	invocation, but indirect <tt>invoke</tt>s are just as possible, branching
				2539	off an arbitrary pointer to function value.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2540
				2541	<li>'<tt>function ptr val</tt>': An LLVM value containing a pointer to a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2542	function to be invoked. </li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2543
				2544	<li>'<tt>function args</tt>': argument list whose types match the function
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2545	signature argument types. If the function signature indicates the
				2546	function accepts a variable number of arguments, the extra arguments can
				2547	be specified.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2548
				2549	<li>'<tt>normal label</tt>': the label reached when the called function
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2550	executes a '<tt><a href="#i_ret">ret</a></tt>' instruction. </li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2551
				2552	<li>'<tt>exception label</tt>': the label reached when a callee returns with
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2553	the <a href="#i_unwind"><tt>unwind</tt></a> instruction. </li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2554
Devang Patel	d0bfcc7	2008-10-07 17:48:33 +0000	[diff] [blame]	2555	<li>The optional <a href="#fnattrs">function attributes</a> list. Only
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2556	'<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
				2557	'<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2558	</ol>
				2559
				2560	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2561	<p>This instruction is designed to operate as a standard
				2562	'<tt><a href="#i_call">call</a></tt>' instruction in most regards. The
				2563	primary difference is that it establishes an association with a label, which
				2564	is used by the runtime library to unwind the stack.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2565
				2566	<p>This instruction is used in languages with destructors to ensure that proper
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2567	cleanup is performed in the case of either a <tt>longjmp</tt> or a thrown
				2568	exception. Additionally, this is important for implementation of
				2569	'<tt>catch</tt>' clauses in high-level languages that support them.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2570
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2571	<p>For the purposes of the SSA form, the definition of the value returned by the
				2572	'<tt>invoke</tt>' instruction is deemed to occur on the edge from the current
				2573	block to the "normal" label. If the callee unwinds then no return value is
				2574	available.</p>
Dan Gohman	140ba5d	2009-05-22 21:47:08 +0000	[diff] [blame]	2575
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2576	<h5>Example:</h5>
				2577	<pre>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2578	%retval = invoke i32 @Test(i32 15) to label %Continue
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2579	unwind label %TestCleanup <i>; {i32}:retval set</i>
Nick Lewycky	a1c11a1	2008-03-16 07:18:12 +0000	[diff] [blame]	2580	%retval = invoke <a href="#callingconv">coldcc</a> i32 %Testfnptr(i32 15) to label %Continue
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2581	unwind label %TestCleanup <i>; {i32}:retval set</i>
				2582	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2583
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2584	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2585
				2586	<!-- _______________________________________________________________________ -->
				2587
				2588	<div class="doc_subsubsection"> <a name="i_unwind">'<tt>unwind</tt>'
				2589	Instruction</a> </div>
				2590
				2591	<div class="doc_text">
				2592
				2593	<h5>Syntax:</h5>
				2594	<pre>
				2595	unwind
				2596	</pre>
				2597
				2598	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2599	<p>The '<tt>unwind</tt>' instruction unwinds the stack, continuing control flow
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2600	at the first callee in the dynamic call stack which used
				2601	an <a href="#i_invoke"><tt>invoke</tt></a> instruction to perform the call.
				2602	This is primarily used to implement exception handling.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2603
				2604	<h5>Semantics:</h5>
Chris Lattner	8b094fc	2008-04-19 21:01:16 +0000	[diff] [blame]	2605	<p>The '<tt>unwind</tt>' instruction causes execution of the current function to
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2606	immediately halt. The dynamic call stack is then searched for the
				2607	first <a href="#i_invoke"><tt>invoke</tt></a> instruction on the call stack.
				2608	Once found, execution continues at the "exceptional" destination block
				2609	specified by the <tt>invoke</tt> instruction. If there is no <tt>invoke</tt>
				2610	instruction in the dynamic call chain, undefined behavior results.</p>
				2611
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2612	</div>
				2613
				2614	<!-- _______________________________________________________________________ -->
				2615
				2616	<div class="doc_subsubsection"> <a name="i_unreachable">'<tt>unreachable</tt>'
				2617	Instruction</a> </div>
				2618
				2619	<div class="doc_text">
				2620
				2621	<h5>Syntax:</h5>
				2622	<pre>
				2623	unreachable
				2624	</pre>
				2625
				2626	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2627	<p>The '<tt>unreachable</tt>' instruction has no defined semantics. This
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2628	instruction is used to inform the optimizer that a particular portion of the
				2629	code is not reachable. This can be used to indicate that the code after a
				2630	no-return function cannot be reached, and other facts.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2631
				2632	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2633	<p>The '<tt>unreachable</tt>' instruction has no defined semantics.</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2634
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2635	</div>
				2636
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2637	<!-- ======================================================================= -->
				2638	<div class="doc_subsection"> <a name="binaryops">Binary Operations</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2639
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2640	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2641
				2642	<p>Binary operators are used to do most of the computation in a program. They
				2643	require two operands of the same type, execute an operation on them, and
				2644	produce a single value. The operands might represent multiple data, as is
				2645	the case with the <a href="#t_vector">vector</a> data type. The result value
				2646	has the same type as its operands.</p>
				2647
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2648	<p>There are several different binary operators:</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2649
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2650	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2651
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2652	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2653	<div class="doc_subsubsection">
				2654	<a name="i_add">'<tt>add</tt>' Instruction</a>
				2655	</div>
				2656
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2657	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2658
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2659	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2660	<pre>
Dan Gohman	ed5fcb2	2009-07-20 22:41:19 +0000	[diff] [blame]	2661	<result> = add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	46e9601	2009-07-22 22:44:56 +0000	[diff] [blame]	2662	<result> = nuw add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2663	<result> = nsw add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2664	<result> = nuw nsw add <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2665	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2666
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2667	<h5>Overview:</h5>
				2668	<p>The '<tt>add</tt>' instruction returns the sum of its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2669
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2670	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2671	<p>The two arguments to the '<tt>add</tt>' instruction must
				2672	be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
				2673	integer values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2674
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2675	<h5>Semantics:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2676	<p>The value produced is the integer sum of the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2677
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2678	<p>If the sum has unsigned overflow, the result returned is the mathematical
				2679	result modulo 2<sup>n</sup>, where n is the bit width of the result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2680
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2681	<p>Because LLVM integers use a two's complement representation, this instruction
				2682	is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2683
Dan Gohman	46e9601	2009-07-22 22:44:56 +0000	[diff] [blame]	2684	<p><tt>nuw</tt> and <tt>nsw</tt> stand for "No Unsigned Wrap"
				2685	and "No Signed Wrap", respectively. If the <tt>nuw</tt> and/or
				2686	<tt>nsw</tt> keywords are present, the result value of the <tt>add</tt>
				2687	is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohman	ed5fcb2	2009-07-20 22:41:19 +0000	[diff] [blame]	2688
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2689	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2690	<pre>
				2691	<result> = add i32 4, %var <i>; yields {i32}:result = 4 + %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2692	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2693
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2694	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2695
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2696	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2697	<div class="doc_subsubsection">
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2698	<a name="i_fadd">'<tt>fadd</tt>' Instruction</a>
				2699	</div>
				2700
				2701	<div class="doc_text">
				2702
				2703	<h5>Syntax:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2704	<pre>
				2705	<result> = fadd <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2706	</pre>
				2707
				2708	<h5>Overview:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2709	<p>The '<tt>fadd</tt>' instruction returns the sum of its two operands.</p>
				2710
				2711	<h5>Arguments:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2712	<p>The two arguments to the '<tt>fadd</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2713	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
				2714	floating point values. Both arguments must have identical types.</p>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2715
				2716	<h5>Semantics:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2717	<p>The value produced is the floating point sum of the two operands.</p>
				2718
				2719	<h5>Example:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2720	<pre>
				2721	<result> = fadd float 4.0, %var <i>; yields {float}:result = 4.0 + %var</i>
				2722	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2723
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2724	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2725
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2726	<!-- _______________________________________________________________________ -->
				2727	<div class="doc_subsubsection">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2728	<a name="i_sub">'<tt>sub</tt>' Instruction</a>
				2729	</div>
				2730
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2731	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2732
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2733	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2734	<pre>
Dan Gohman	46e9601	2009-07-22 22:44:56 +0000	[diff] [blame]	2735	<result> = sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2736	<result> = nuw sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2737	<result> = nsw sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2738	<result> = nuw nsw sub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2739	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2740
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2741	<h5>Overview:</h5>
				2742	<p>The '<tt>sub</tt>' instruction returns the difference of its two
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2743	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2744
				2745	<p>Note that the '<tt>sub</tt>' instruction is used to represent the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2746	'<tt>neg</tt>' instruction present in most other intermediate
				2747	representations.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2748
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2749	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2750	<p>The two arguments to the '<tt>sub</tt>' instruction must
				2751	be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
				2752	integer values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2753
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2754	<h5>Semantics:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2755	<p>The value produced is the integer difference of the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2756
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2757	<p>If the difference has unsigned overflow, the result returned is the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2758	mathematical result modulo 2<sup>n</sup>, where n is the bit width of the
				2759	result.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2760
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2761	<p>Because LLVM integers use a two's complement representation, this instruction
				2762	is appropriate for both signed and unsigned integers.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2763
Dan Gohman	46e9601	2009-07-22 22:44:56 +0000	[diff] [blame]	2764	<p><tt>nuw</tt> and <tt>nsw</tt> stand for "No Unsigned Wrap"
				2765	and "No Signed Wrap", respectively. If the <tt>nuw</tt> and/or
				2766	<tt>nsw</tt> keywords are present, the result value of the <tt>sub</tt>
				2767	is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohman	ed5fcb2	2009-07-20 22:41:19 +0000	[diff] [blame]	2768
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2769	<h5>Example:</h5>
				2770	<pre>
				2771	<result> = sub i32 4, %var <i>; yields {i32}:result = 4 - %var</i>
				2772	<result> = sub i32 0, %val <i>; yields {i32}:result = -%var</i>
				2773	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2774
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2775	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2776
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2777	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2778	<div class="doc_subsubsection">
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2779	<a name="i_fsub">'<tt>fsub</tt>' Instruction</a>
				2780	</div>
				2781
				2782	<div class="doc_text">
				2783
				2784	<h5>Syntax:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2785	<pre>
				2786	<result> = fsub <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2787	</pre>
				2788
				2789	<h5>Overview:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2790	<p>The '<tt>fsub</tt>' instruction returns the difference of its two
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2791	operands.</p>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2792
				2793	<p>Note that the '<tt>fsub</tt>' instruction is used to represent the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2794	'<tt>fneg</tt>' instruction present in most other intermediate
				2795	representations.</p>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2796
				2797	<h5>Arguments:</h5>
Bill Wendling	1a2630a	2009-07-20 02:32:41 +0000	[diff] [blame]	2798	<p>The two arguments to the '<tt>fsub</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2799	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
				2800	floating point values. Both arguments must have identical types.</p>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2801
				2802	<h5>Semantics:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2803	<p>The value produced is the floating point difference of the two operands.</p>
				2804
				2805	<h5>Example:</h5>
				2806	<pre>
				2807	<result> = fsub float 4.0, %var <i>; yields {float}:result = 4.0 - %var</i>
				2808	<result> = fsub float -0.0, %val <i>; yields {float}:result = -%var</i>
				2809	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2810
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2811	</div>
				2812
				2813	<!-- _______________________________________________________________________ -->
				2814	<div class="doc_subsubsection">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2815	<a name="i_mul">'<tt>mul</tt>' Instruction</a>
				2816	</div>
				2817
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2818	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2819
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2820	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2821	<pre>
Dan Gohman	46e9601	2009-07-22 22:44:56 +0000	[diff] [blame]	2822	<result> = mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2823	<result> = nuw mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2824	<result> = nsw mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2825	<result> = nuw nsw mul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2826	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2827
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2828	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2829	<p>The '<tt>mul</tt>' instruction returns the product of its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2830
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2831	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2832	<p>The two arguments to the '<tt>mul</tt>' instruction must
				2833	be <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
				2834	integer values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2835
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2836	<h5>Semantics:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2837	<p>The value produced is the integer product of the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2838
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2839	<p>If the result of the multiplication has unsigned overflow, the result
				2840	returned is the mathematical result modulo 2<sup>n</sup>, where n is the bit
				2841	width of the result.</p>
				2842
				2843	<p>Because LLVM integers use a two's complement representation, and the result
				2844	is the same width as the operands, this instruction returns the correct
				2845	result for both signed and unsigned integers. If a full product
				2846	(e.g. <tt>i32</tt>x<tt>i32</tt>-><tt>i64</tt>) is needed, the operands should
				2847	be sign-extended or zero-extended as appropriate to the width of the full
				2848	product.</p>
				2849
Dan Gohman	46e9601	2009-07-22 22:44:56 +0000	[diff] [blame]	2850	<p><tt>nuw</tt> and <tt>nsw</tt> stand for "No Unsigned Wrap"
				2851	and "No Signed Wrap", respectively. If the <tt>nuw</tt> and/or
				2852	<tt>nsw</tt> keywords are present, the result value of the <tt>mul</tt>
				2853	is undefined if unsigned and/or signed overflow, respectively, occurs.</p>
Dan Gohman	ed5fcb2	2009-07-20 22:41:19 +0000	[diff] [blame]	2854
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2855	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2856	<pre>
				2857	<result> = mul i32 4, %var <i>; yields {i32}:result = 4 * %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2858	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2859
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2860	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2861
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2862	<!-- _______________________________________________________________________ -->
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2863	<div class="doc_subsubsection">
				2864	<a name="i_fmul">'<tt>fmul</tt>' Instruction</a>
				2865	</div>
				2866
				2867	<div class="doc_text">
				2868
				2869	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2870	<pre>
				2871	<result> = fmul <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2872	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2873
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2874	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2875	<p>The '<tt>fmul</tt>' instruction returns the product of its two operands.</p>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2876
				2877	<h5>Arguments:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2878	<p>The two arguments to the '<tt>fmul</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2879	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
				2880	floating point values. Both arguments must have identical types.</p>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2881
				2882	<h5>Semantics:</h5>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2883	<p>The value produced is the floating point product of the two operands.</p>
				2884
				2885	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2886	<pre>
				2887	<result> = fmul float 4.0, %var <i>; yields {float}:result = 4.0 * %var</i>
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2888	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2889
Dan Gohman	7ce405e	2009-06-04 22:49:04 +0000	[diff] [blame]	2890	</div>
				2891
				2892	<!-- _______________________________________________________________________ -->
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2893	<div class="doc_subsubsection"> <a name="i_udiv">'<tt>udiv</tt>' Instruction
				2894	</a></div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2895
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2896	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2897
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2898	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2899	<pre>
				2900	<result> = udiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2901	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2902
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2903	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2904	<p>The '<tt>udiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2905
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2906	<h5>Arguments:</h5>
				2907	<p>The two arguments to the '<tt>udiv</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2908	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2909	values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2910
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2911	<h5>Semantics:</h5>
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2912	<p>The value produced is the unsigned integer quotient of the two operands.</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2913
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2914	<p>Note that unsigned integer division and signed integer division are distinct
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2915	operations; for signed integer division, use '<tt>sdiv</tt>'.</p>
				2916
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2917	<p>Division by zero leads to undefined behavior.</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2918
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2919	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2920	<pre>
				2921	<result> = udiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2922	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2923
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2924	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2925
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2926	<!-- _______________________________________________________________________ -->
				2927	<div class="doc_subsubsection"> <a name="i_sdiv">'<tt>sdiv</tt>' Instruction
				2928	</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2929
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2930	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2931
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2932	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2933	<pre>
Dan Gohman	ed5fcb2	2009-07-20 22:41:19 +0000	[diff] [blame]	2934	<result> = sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				2935	<result> = exact sdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2936	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2937
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2938	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2939	<p>The '<tt>sdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2940
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2941	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2942	<p>The two arguments to the '<tt>sdiv</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2943	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				2944	values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2945
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2946	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2947	<p>The value produced is the signed integer quotient of the two operands rounded
				2948	towards zero.</p>
				2949
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2950	<p>Note that signed integer division and unsigned integer division are distinct
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2951	operations; for unsigned integer division, use '<tt>udiv</tt>'.</p>
				2952
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	2953	<p>Division by zero leads to undefined behavior. Overflow also leads to
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2954	undefined behavior; this is a rare case, but can occur, for example, by doing
				2955	a 32-bit division of -2147483648 by -1.</p>
				2956
Dan Gohman	67fa48e	2009-07-22 00:04:19 +0000	[diff] [blame]	2957	<p>If the <tt>exact</tt> keyword is present, the result value of the
				2958	<tt>sdiv</tt> is undefined if the result would be rounded or if overflow
				2959	would occur.</p>
Dan Gohman	ed5fcb2	2009-07-20 22:41:19 +0000	[diff] [blame]	2960
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2961	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2962	<pre>
				2963	<result> = sdiv i32 4, %var <i>; yields {i32}:result = 4 / %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2964	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2965
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2966	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2967
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2968	<!-- _______________________________________________________________________ -->
				2969	<div class="doc_subsubsection"> <a name="i_fdiv">'<tt>fdiv</tt>'
				2970	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2971
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2972	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2973
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2974	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2975	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	2976	<result> = fdiv <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2977	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2978
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2979	<h5>Overview:</h5>
				2980	<p>The '<tt>fdiv</tt>' instruction returns the quotient of its two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2981
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2982	<h5>Arguments:</h5>
				2983	<p>The two arguments to the '<tt>fdiv</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2984	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
				2985	floating point values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2986
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2987	<h5>Semantics:</h5>
				2988	<p>The value produced is the floating point quotient of the two operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2989
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2990	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2991	<pre>
				2992	<result> = fdiv float 4.0, %var <i>; yields {float}:result = 4.0 / %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2993	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	2994
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2995	</div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	2996
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	2997	<!-- _______________________________________________________________________ -->
				2998	<div class="doc_subsubsection"> <a name="i_urem">'<tt>urem</tt>' Instruction</a>
				2999	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3000
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3001	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3002
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3003	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3004	<pre>
				3005	<result> = urem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3006	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3007
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3008	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3009	<p>The '<tt>urem</tt>' instruction returns the remainder from the unsigned
				3010	division of its two arguments.</p>
				3011
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3012	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3013	<p>The two arguments to the '<tt>urem</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3014	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3015	values. Both arguments must have identical types.</p>
				3016
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3017	<h5>Semantics:</h5>
				3018	<p>This instruction returns the unsigned integer <i>remainder</i> of a division.
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3019	This instruction always performs an unsigned division to get the
				3020	remainder.</p>
				3021
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	3022	<p>Note that unsigned integer remainder and signed integer remainder are
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3023	distinct operations; for signed integer remainder, use '<tt>srem</tt>'.</p>
				3024
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	3025	<p>Taking the remainder of a division by zero leads to undefined behavior.</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3026
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3027	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3028	<pre>
				3029	<result> = urem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3030	</pre>
				3031
				3032	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3033
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3034	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3035	<div class="doc_subsubsection">
				3036	<a name="i_srem">'<tt>srem</tt>' Instruction</a>
				3037	</div>
				3038
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3039	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3040
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3041	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3042	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3043	<result> = srem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3044	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3045
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3046	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3047	<p>The '<tt>srem</tt>' instruction returns the remainder from the signed
				3048	division of its two operands. This instruction can also take
				3049	<a href="#t_vector">vector</a> versions of the values in which case the
				3050	elements must be integers.</p>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	3051
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3052	<h5>Arguments:</h5>
				3053	<p>The two arguments to the '<tt>srem</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3054	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3055	values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3056
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3057	<h5>Semantics:</h5>
				3058	<p>This instruction returns the <i>remainder</i> of a division (where the result
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3059	has the same sign as the dividend, <tt>op1</tt>), not the <i>modulo</i>
				3060	operator (where the result has the same sign as the divisor, <tt>op2</tt>) of
				3061	a value. For more information about the difference,
				3062	see <a href="http://mathforum.org/dr.math/problems/anne.4.28.99.html">The
				3063	Math Forum</a>. For a table of how this is implemented in various languages,
				3064	please see <a href="http://en.wikipedia.org/wiki/Modulo_operation">
				3065	Wikipedia: modulo operation</a>.</p>
				3066
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	3067	<p>Note that signed integer remainder and unsigned integer remainder are
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3068	distinct operations; for unsigned integer remainder, use '<tt>urem</tt>'.</p>
				3069
Chris Lattner	9aba1e2	2008-01-28 00:36:27 +0000	[diff] [blame]	3070	<p>Taking the remainder of a division by zero leads to undefined behavior.
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3071	Overflow also leads to undefined behavior; this is a rare case, but can
				3072	occur, for example, by taking the remainder of a 32-bit division of
				3073	-2147483648 by -1. (The remainder doesn't actually overflow, but this rule
				3074	lets srem be implemented using instructions that return both the result of
				3075	the division and the remainder.)</p>
				3076
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3077	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3078	<pre>
				3079	<result> = srem i32 4, %var <i>; yields {i32}:result = 4 % %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3080	</pre>
				3081
				3082	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3083
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3084	<!-- _______________________________________________________________________ -->
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3085	<div class="doc_subsubsection">
				3086	<a name="i_frem">'<tt>frem</tt>' Instruction</a> </div>
				3087
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3088	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3089
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3090	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3091	<pre>
				3092	<result> = frem <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3093	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3094
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3095	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3096	<p>The '<tt>frem</tt>' instruction returns the remainder from the division of
				3097	its two operands.</p>
				3098
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3099	<h5>Arguments:</h5>
				3100	<p>The two arguments to the '<tt>frem</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3101	<a href="#t_floating">floating point</a> or <a href="#t_vector">vector</a> of
				3102	floating point values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3103
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3104	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3105	<p>This instruction returns the <i>remainder</i> of a division. The remainder
				3106	has the same sign as the dividend.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3107
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3108	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3109	<pre>
				3110	<result> = frem float 4.0, %var <i>; yields {float}:result = 4.0 % %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3111	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3112
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3113	</div>
				3114
				3115	<!-- ======================================================================= -->
				3116	<div class="doc_subsection"> <a name="bitwiseops">Bitwise Binary
				3117	Operations</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3118
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3119	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3120
				3121	<p>Bitwise binary operators are used to do various forms of bit-twiddling in a
				3122	program. They are generally very efficient instructions and can commonly be
				3123	strength reduced from other instructions. They require two operands of the
				3124	same type, execute an operation on them, and produce a single value. The
				3125	resulting value is the same type as its operands.</p>
				3126
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3127	</div>
				3128
				3129	<!-- _______________________________________________________________________ -->
				3130	<div class="doc_subsubsection"> <a name="i_shl">'<tt>shl</tt>'
				3131	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3132
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3133	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3134
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3135	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3136	<pre>
				3137	<result> = shl <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3138	</pre>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3139
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3140	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3141	<p>The '<tt>shl</tt>' instruction returns the first operand shifted to the left
				3142	a specified number of bits.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3143
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3144	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3145	<p>Both arguments to the '<tt>shl</tt>' instruction must be the
				3146	same <a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of
				3147	integer type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3148
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3149	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3150	<p>The value produced is <tt>op1</tt> * 2<sup><tt>op2</tt></sup> mod
				3151	2<sup>n</sup>, where <tt>n</tt> is the width of the result. If <tt>op2</tt>
				3152	is (statically or dynamically) negative or equal to or larger than the number
				3153	of bits in <tt>op1</tt>, the result is undefined. If the arguments are
				3154	vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
				3155	shift amount in <tt>op2</tt>.</p>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3156
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3157	<h5>Example:</h5>
				3158	<pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3159	<result> = shl i32 4, %var <i>; yields {i32}: 4 << %var</i>
				3160	<result> = shl i32 4, 2 <i>; yields {i32}: 16</i>
				3161	<result> = shl i32 1, 10 <i>; yields {i32}: 1024</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3162	<result> = shl i32 1, 32 <i>; undefined</i>
Mon P Wang	9901e73	2008-12-09 05:46:39 +0000	[diff] [blame]	3163	<result> = shl <2 x i32> < i32 1, i32 1>, < i32 1, i32 2> <i>; yields: result=<2 x i32> < i32 2, i32 4></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3164	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3165
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3166	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3167
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3168	<!-- _______________________________________________________________________ -->
				3169	<div class="doc_subsubsection"> <a name="i_lshr">'<tt>lshr</tt>'
				3170	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3171
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3172	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3173
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3174	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3175	<pre>
				3176	<result> = lshr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3177	</pre>
				3178
				3179	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3180	<p>The '<tt>lshr</tt>' instruction (logical shift right) returns the first
				3181	operand shifted to the right a specified number of bits with zero fill.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3182
				3183	<h5>Arguments:</h5>
				3184	<p>Both arguments to the '<tt>lshr</tt>' instruction must be the same
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3185	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3186	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3187
				3188	<h5>Semantics:</h5>
				3189	<p>This instruction always performs a logical shift right operation. The most
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3190	significant bits of the result will be filled with zero bits after the shift.
				3191	If <tt>op2</tt> is (statically or dynamically) equal to or larger than the
				3192	number of bits in <tt>op1</tt>, the result is undefined. If the arguments are
				3193	vectors, each vector element of <tt>op1</tt> is shifted by the corresponding
				3194	shift amount in <tt>op2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3195
				3196	<h5>Example:</h5>
				3197	<pre>
				3198	<result> = lshr i32 4, 1 <i>; yields {i32}:result = 2</i>
				3199	<result> = lshr i32 4, 2 <i>; yields {i32}:result = 1</i>
				3200	<result> = lshr i8 4, 3 <i>; yields {i8}:result = 0</i>
				3201	<result> = lshr i8 -2, 1 <i>; yields {i8}:result = 0x7FFFFFFF </i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3202	<result> = lshr i32 1, 32 <i>; undefined</i>
Mon P Wang	9901e73	2008-12-09 05:46:39 +0000	[diff] [blame]	3203	<result> = lshr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 2> <i>; yields: result=<2 x i32> < i32 0x7FFFFFFF, i32 1></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3204	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3205
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3206	</div>
				3207
				3208	<!-- _______________________________________________________________________ -->
				3209	<div class="doc_subsubsection"> <a name="i_ashr">'<tt>ashr</tt>'
				3210	Instruction</a> </div>
				3211	<div class="doc_text">
				3212
				3213	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3214	<pre>
				3215	<result> = ashr <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3216	</pre>
				3217
				3218	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3219	<p>The '<tt>ashr</tt>' instruction (arithmetic shift right) returns the first
				3220	operand shifted to the right a specified number of bits with sign
				3221	extension.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3222
				3223	<h5>Arguments:</h5>
				3224	<p>Both arguments to the '<tt>ashr</tt>' instruction must be the same
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3225	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3226	type. '<tt>op2</tt>' is treated as an unsigned value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3227
				3228	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3229	<p>This instruction always performs an arithmetic shift right operation, The
				3230	most significant bits of the result will be filled with the sign bit
				3231	of <tt>op1</tt>. If <tt>op2</tt> is (statically or dynamically) equal to or
				3232	larger than the number of bits in <tt>op1</tt>, the result is undefined. If
				3233	the arguments are vectors, each vector element of <tt>op1</tt> is shifted by
				3234	the corresponding shift amount in <tt>op2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3235
				3236	<h5>Example:</h5>
				3237	<pre>
				3238	<result> = ashr i32 4, 1 <i>; yields {i32}:result = 2</i>
				3239	<result> = ashr i32 4, 2 <i>; yields {i32}:result = 1</i>
				3240	<result> = ashr i8 4, 3 <i>; yields {i8}:result = 0</i>
				3241	<result> = ashr i8 -2, 1 <i>; yields {i8}:result = -1</i>
Chris Lattner	d939d9f	2007-10-03 21:01:14 +0000	[diff] [blame]	3242	<result> = ashr i32 1, 32 <i>; undefined</i>
Mon P Wang	9901e73	2008-12-09 05:46:39 +0000	[diff] [blame]	3243	<result> = ashr <2 x i32> < i32 -2, i32 4>, < i32 1, i32 3> <i>; yields: result=<2 x i32> < i32 -1, i32 0></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3244	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3245
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3246	</div>
				3247
				3248	<!-- _______________________________________________________________________ -->
				3249	<div class="doc_subsubsection"> <a name="i_and">'<tt>and</tt>'
				3250	Instruction</a> </div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3251
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3252	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3253
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3254	<h5>Syntax:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3255	<pre>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	3256	<result> = and <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3257	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3258
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3259	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3260	<p>The '<tt>and</tt>' instruction returns the bitwise logical and of its two
				3261	operands.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3262
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3263	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3264	<p>The two arguments to the '<tt>and</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3265	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3266	values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3267
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3268	<h5>Semantics:</h5>
				3269	<p>The truth table used for the '<tt>and</tt>' instruction is:</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3270
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3271	<table border="1" cellspacing="0" cellpadding="4">
				3272	<tbody>
				3273	<tr>
				3274	<td>In0</td>
				3275	<td>In1</td>
				3276	<td>Out</td>
				3277	</tr>
				3278	<tr>
				3279	<td>0</td>
				3280	<td>0</td>
				3281	<td>0</td>
				3282	</tr>
				3283	<tr>
				3284	<td>0</td>
				3285	<td>1</td>
				3286	<td>0</td>
				3287	</tr>
				3288	<tr>
				3289	<td>1</td>
				3290	<td>0</td>
				3291	<td>0</td>
				3292	</tr>
				3293	<tr>
				3294	<td>1</td>
				3295	<td>1</td>
				3296	<td>1</td>
				3297	</tr>
				3298	</tbody>
				3299	</table>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3300
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3301	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3302	<pre>
				3303	<result> = and i32 4, %var <i>; yields {i32}:result = 4 & %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3304	<result> = and i32 15, 40 <i>; yields {i32}:result = 8</i>
				3305	<result> = and i32 4, 8 <i>; yields {i32}:result = 0</i>
				3306	</pre>
				3307	</div>
				3308	<!-- _______________________________________________________________________ -->
				3309	<div class="doc_subsubsection"> <a name="i_or">'<tt>or</tt>' Instruction</a> </div>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3310
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3311	<div class="doc_text">
				3312
				3313	<h5>Syntax:</h5>
				3314	<pre>
				3315	<result> = or <ty> <op1>, <op2> <i>; yields {ty}:result</i>
				3316	</pre>
				3317
				3318	<h5>Overview:</h5>
				3319	<p>The '<tt>or</tt>' instruction returns the bitwise logical inclusive or of its
				3320	two operands.</p>
				3321
				3322	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3323	<p>The two arguments to the '<tt>or</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3324	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3325	values. Both arguments must have identical types.</p>
				3326
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3327	<h5>Semantics:</h5>
				3328	<p>The truth table used for the '<tt>or</tt>' instruction is:</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3329
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3330	<table border="1" cellspacing="0" cellpadding="4">
				3331	<tbody>
				3332	<tr>
				3333	<td>In0</td>
				3334	<td>In1</td>
				3335	<td>Out</td>
				3336	</tr>
				3337	<tr>
				3338	<td>0</td>
				3339	<td>0</td>
				3340	<td>0</td>
				3341	</tr>
				3342	<tr>
				3343	<td>0</td>
				3344	<td>1</td>
				3345	<td>1</td>
				3346	</tr>
				3347	<tr>
				3348	<td>1</td>
				3349	<td>0</td>
				3350	<td>1</td>
				3351	</tr>
				3352	<tr>
				3353	<td>1</td>
				3354	<td>1</td>
				3355	<td>1</td>
				3356	</tr>
				3357	</tbody>
				3358	</table>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3359
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3360	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3361	<pre>
				3362	<result> = or i32 4, %var <i>; yields {i32}:result = 4 \| %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3363	<result> = or i32 15, 40 <i>; yields {i32}:result = 47</i>
				3364	<result> = or i32 4, 8 <i>; yields {i32}:result = 12</i>
				3365	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3366
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3367	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3368
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3369	<!-- _______________________________________________________________________ -->
				3370	<div class="doc_subsubsection"> <a name="i_xor">'<tt>xor</tt>'
				3371	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3372
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3373	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3374
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3375	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3376	<pre>
				3377	<result> = xor <ty> <op1>, <op2> <i>; yields {ty}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3378	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3379
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3380	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3381	<p>The '<tt>xor</tt>' instruction returns the bitwise logical exclusive or of
				3382	its two operands. The <tt>xor</tt> is used to implement the "one's
				3383	complement" operation, which is the "~" operator in C.</p>
				3384
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3385	<h5>Arguments:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3386	<p>The two arguments to the '<tt>xor</tt>' instruction must be
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3387	<a href="#t_integer">integer</a> or <a href="#t_vector">vector</a> of integer
				3388	values. Both arguments must have identical types.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	3389
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3390	<h5>Semantics:</h5>
				3391	<p>The truth table used for the '<tt>xor</tt>' instruction is:</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3392
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3393	<table border="1" cellspacing="0" cellpadding="4">
				3394	<tbody>
				3395	<tr>
				3396	<td>In0</td>
				3397	<td>In1</td>
				3398	<td>Out</td>
				3399	</tr>
				3400	<tr>
				3401	<td>0</td>
				3402	<td>0</td>
				3403	<td>0</td>
				3404	</tr>
				3405	<tr>
				3406	<td>0</td>
				3407	<td>1</td>
				3408	<td>1</td>
				3409	</tr>
				3410	<tr>
				3411	<td>1</td>
				3412	<td>0</td>
				3413	<td>1</td>
				3414	</tr>
				3415	<tr>
				3416	<td>1</td>
				3417	<td>1</td>
				3418	<td>0</td>
				3419	</tr>
				3420	</tbody>
				3421	</table>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3422
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3423	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3424	<pre>
				3425	<result> = xor i32 4, %var <i>; yields {i32}:result = 4 ^ %var</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3426	<result> = xor i32 15, 40 <i>; yields {i32}:result = 39</i>
				3427	<result> = xor i32 4, 8 <i>; yields {i32}:result = 12</i>
				3428	<result> = xor i32 %V, -1 <i>; yields {i32}:result = ~%V</i>
				3429	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3430
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3431	</div>
				3432
				3433	<!-- ======================================================================= -->
				3434	<div class="doc_subsection">
				3435	<a name="vectorops">Vector Operations</a>
				3436	</div>
				3437
				3438	<div class="doc_text">
				3439
				3440	<p>LLVM supports several instructions to represent vector operations in a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3441	target-independent manner. These instructions cover the element-access and
				3442	vector-specific operations needed to process vectors effectively. While LLVM
				3443	does directly support these vector operations, many sophisticated algorithms
				3444	will want to use target-specific intrinsics to take full advantage of a
				3445	specific target.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3446
				3447	</div>
				3448
				3449	<!-- _______________________________________________________________________ -->
				3450	<div class="doc_subsubsection">
				3451	<a name="i_extractelement">'<tt>extractelement</tt>' Instruction</a>
				3452	</div>
				3453
				3454	<div class="doc_text">
				3455
				3456	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3457	<pre>
				3458	<result> = extractelement <n x <ty>> <val>, i32 <idx> <i>; yields <ty></i>
				3459	</pre>
				3460
				3461	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3462	<p>The '<tt>extractelement</tt>' instruction extracts a single scalar element
				3463	from a vector at a specified index.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3464
				3465
				3466	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3467	<p>The first operand of an '<tt>extractelement</tt>' instruction is a value
				3468	of <a href="#t_vector">vector</a> type. The second operand is an index
				3469	indicating the position from which to extract the element. The index may be
				3470	a variable.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3471
				3472	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3473	<p>The result is a scalar of the same type as the element type of
				3474	<tt>val</tt>. Its value is the value at position <tt>idx</tt> of
				3475	<tt>val</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
				3476	results are undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3477
				3478	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3479	<pre>
				3480	%result = extractelement <4 x i32> %vec, i32 0 <i>; yields i32</i>
				3481	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3482
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3483	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3484
				3485	<!-- _______________________________________________________________________ -->
				3486	<div class="doc_subsubsection">
				3487	<a name="i_insertelement">'<tt>insertelement</tt>' Instruction</a>
				3488	</div>
				3489
				3490	<div class="doc_text">
				3491
				3492	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3493	<pre>
Dan Gohman	bcc3c50	2008-05-12 23:38:42 +0000	[diff] [blame]	3494	<result> = insertelement <n x <ty>> <val>, <ty> <elt>, i32 <idx> <i>; yields <n x <ty>></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3495	</pre>
				3496
				3497	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3498	<p>The '<tt>insertelement</tt>' instruction inserts a scalar element into a
				3499	vector at a specified index.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3500
				3501	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3502	<p>The first operand of an '<tt>insertelement</tt>' instruction is a value
				3503	of <a href="#t_vector">vector</a> type. The second operand is a scalar value
				3504	whose type must equal the element type of the first operand. The third
				3505	operand is an index indicating the position at which to insert the value.
				3506	The index may be a variable.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3507
				3508	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3509	<p>The result is a vector of the same type as <tt>val</tt>. Its element values
				3510	are those of <tt>val</tt> except at position <tt>idx</tt>, where it gets the
				3511	value <tt>elt</tt>. If <tt>idx</tt> exceeds the length of <tt>val</tt>, the
				3512	results are undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3513
				3514	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3515	<pre>
				3516	%result = insertelement <4 x i32> %vec, i32 1, i32 0 <i>; yields <4 x i32></i>
				3517	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3518
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3519	</div>
				3520
				3521	<!-- _______________________________________________________________________ -->
				3522	<div class="doc_subsubsection">
				3523	<a name="i_shufflevector">'<tt>shufflevector</tt>' Instruction</a>
				3524	</div>
				3525
				3526	<div class="doc_text">
				3527
				3528	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3529	<pre>
Mon P Wang	bff5d9c	2008-11-10 04:46:22 +0000	[diff] [blame]	3530	<result> = shufflevector <n x <ty>> <v1>, <n x <ty>> <v2>, <m x i32> <mask> <i>; yields <m x <ty>></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3531	</pre>
				3532
				3533	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3534	<p>The '<tt>shufflevector</tt>' instruction constructs a permutation of elements
				3535	from two input vectors, returning a vector with the same element type as the
				3536	input and length that is the same as the shuffle mask.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3537
				3538	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3539	<p>The first two operands of a '<tt>shufflevector</tt>' instruction are vectors
				3540	with types that match each other. The third argument is a shuffle mask whose
				3541	element type is always 'i32'. The result of the instruction is a vector
				3542	whose length is the same as the shuffle mask and whose element type is the
				3543	same as the element type of the first two operands.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3544
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3545	<p>The shuffle mask operand is required to be a constant vector with either
				3546	constant integer or undef values.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3547
				3548	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3549	<p>The elements of the two input vectors are numbered from left to right across
				3550	both of the vectors. The shuffle mask operand specifies, for each element of
				3551	the result vector, which element of the two input vectors the result element
				3552	gets. The element selector may be undef (meaning "don't care") and the
				3553	second operand may be undef if performing a shuffle from only one vector.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3554
				3555	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3556	<pre>
				3557	%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
				3558	<4 x i32> <i32 0, i32 4, i32 1, i32 5> <i>; yields <4 x i32></i>
				3559	%result = shufflevector <4 x i32> %v1, <4 x i32> undef,
				3560	<4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i> - Identity shuffle.
Mon P Wang	bff5d9c	2008-11-10 04:46:22 +0000	[diff] [blame]	3561	%result = shufflevector <8 x i32> %v1, <8 x i32> undef,
				3562	<4 x i32> <i32 0, i32 1, i32 2, i32 3> <i>; yields <4 x i32></i>
				3563	%result = shufflevector <4 x i32> %v1, <4 x i32> %v2,
				3564	<8 x i32> <i32 0, i32 1, i32 2, i32 3, i32 4, i32 5, i32 6, i32 7 > <i>; yields <8 x i32></i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3565	</pre>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3566
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3567	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3568
				3569	<!-- ======================================================================= -->
				3570	<div class="doc_subsection">
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3571	<a name="aggregateops">Aggregate Operations</a>
				3572	</div>
				3573
				3574	<div class="doc_text">
				3575
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3576	<p>LLVM supports several instructions for working with aggregate values.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3577
				3578	</div>
				3579
				3580	<!-- _______________________________________________________________________ -->
				3581	<div class="doc_subsubsection">
				3582	<a name="i_extractvalue">'<tt>extractvalue</tt>' Instruction</a>
				3583	</div>
				3584
				3585	<div class="doc_text">
				3586
				3587	<h5>Syntax:</h5>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3588	<pre>
				3589	<result> = extractvalue <aggregate type> <val>, <idx>{, <idx>}*
				3590	</pre>
				3591
				3592	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3593	<p>The '<tt>extractvalue</tt>' instruction extracts the value of a struct field
				3594	or array element from an aggregate value.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3595
				3596	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3597	<p>The first operand of an '<tt>extractvalue</tt>' instruction is a value
				3598	of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
				3599	operands are constant indices to specify which value to extract in a similar
				3600	manner as indices in a
				3601	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3602
				3603	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3604	<p>The result is the value at the position in the aggregate specified by the
				3605	index operands.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3606
				3607	<h5>Example:</h5>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3608	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3609	%result = extractvalue {i32, float} %agg, 0 <i>; yields i32</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3610	</pre>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3611
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3612	</div>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3613
				3614	<!-- _______________________________________________________________________ -->
				3615	<div class="doc_subsubsection">
				3616	<a name="i_insertvalue">'<tt>insertvalue</tt>' Instruction</a>
				3617	</div>
				3618
				3619	<div class="doc_text">
				3620
				3621	<h5>Syntax:</h5>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3622	<pre>
Dan Gohman	e5febe4	2008-05-31 00:58:22 +0000	[diff] [blame]	3623	<result> = insertvalue <aggregate type> <val>, <ty> <val>, <idx> <i>; yields <n x <ty>></i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3624	</pre>
				3625
				3626	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3627	<p>The '<tt>insertvalue</tt>' instruction inserts a value into a struct field or
				3628	array element in an aggregate.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3629
				3630
				3631	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3632	<p>The first operand of an '<tt>insertvalue</tt>' instruction is a value
				3633	of <a href="#t_struct">struct</a> or <a href="#t_array">array</a> type. The
				3634	second operand is a first-class value to insert. The following operands are
				3635	constant indices indicating the position at which to insert the value in a
				3636	similar manner as indices in a
				3637	'<tt><a href="#i_getelementptr">getelementptr</a></tt>' instruction. The
				3638	value to insert must have the same type as the value identified by the
				3639	indices.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3640
				3641	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3642	<p>The result is an aggregate of the same type as <tt>val</tt>. Its value is
				3643	that of <tt>val</tt> except that the value at the position specified by the
				3644	indices is that of <tt>elt</tt>.</p>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3645
				3646	<h5>Example:</h5>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3647	<pre>
Dan Gohman	b1aab4e	2008-06-23 15:26:37 +0000	[diff] [blame]	3648	%result = insertvalue {i32, float} %agg, i32 1, 0 <i>; yields {i32, float}</i>
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3649	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3650
Dan Gohman	74d6faf	2008-05-12 23:51:09 +0000	[diff] [blame]	3651	</div>
				3652
				3653
				3654	<!-- ======================================================================= -->
				3655	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3656	<a name="memoryops">Memory Access and Addressing Operations</a>
				3657	</div>
				3658
				3659	<div class="doc_text">
				3660
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3661	<p>A key design point of an SSA-based representation is how it represents
				3662	memory. In LLVM, no memory locations are in SSA form, which makes things
				3663	very simple. This section describes how to read, write, allocate, and free
				3664	memory in LLVM.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3665
				3666	</div>
				3667
				3668	<!-- _______________________________________________________________________ -->
				3669	<div class="doc_subsubsection">
				3670	<a name="i_malloc">'<tt>malloc</tt>' Instruction</a>
				3671	</div>
				3672
				3673	<div class="doc_text">
				3674
				3675	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3676	<pre>
				3677	<result> = malloc <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3678	</pre>
				3679
				3680	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3681	<p>The '<tt>malloc</tt>' instruction allocates memory from the system heap and
				3682	returns a pointer to it. The object is always allocated in the generic
				3683	address space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3684
				3685	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3686	<p>The '<tt>malloc</tt>' instruction allocates
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3687	<tt>sizeof(<type>)*NumElements</tt> bytes of memory from the operating
				3688	system and returns a pointer of the appropriate type to the program. If
				3689	"NumElements" is specified, it is the number of elements allocated, otherwise
				3690	"NumElements" is defaulted to be one. If a constant alignment is specified,
				3691	the value result of the allocation is guaranteed to be aligned to at least
				3692	that boundary. If not specified, or if zero, the target can choose to align
				3693	the allocation on any convenient boundary compatible with the type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3694
				3695	<p>'<tt>type</tt>' must be a sized type.</p>
				3696
				3697	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3698	<p>Memory is allocated using the system "<tt>malloc</tt>" function, and a
				3699	pointer is returned. The result of a zero byte allocation is undefined. The
				3700	result is null if there is insufficient memory available.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3701
				3702	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3703	<pre>
Dan Gohman	f54f50a	2009-01-04 23:49:44 +0000	[diff] [blame]	3704	%array = malloc [4 x i8] <i>; yields {[%4 x i8]*}:array</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3705
				3706	%size = <a href="#i_add">add</a> i32 2, 2 <i>; yields {i32}:size = i32 4</i>
				3707	%array1 = malloc i8, i32 4 <i>; yields {i8*}:array1</i>
				3708	%array2 = malloc [12 x i8], i32 %size <i>; yields {[12 x i8]*}:array2</i>
				3709	%array3 = malloc i32, i32 4, align 1024 <i>; yields {i32*}:array3</i>
				3710	%array4 = malloc i32, align 1024 <i>; yields {i32*}:array4</i>
				3711	</pre>
Dan Gohman	6096719	2009-01-12 23:12:39 +0000	[diff] [blame]	3712
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3713	<p>Note that the code generator does not yet respect the alignment value.</p>
Dan Gohman	6096719	2009-01-12 23:12:39 +0000	[diff] [blame]	3714
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3715	</div>
				3716
				3717	<!-- _______________________________________________________________________ -->
				3718	<div class="doc_subsubsection">
				3719	<a name="i_free">'<tt>free</tt>' Instruction</a>
				3720	</div>
				3721
				3722	<div class="doc_text">
				3723
				3724	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3725	<pre>
Dan Gohman	f54f50a	2009-01-04 23:49:44 +0000	[diff] [blame]	3726	free <type> <value> <i>; yields {void}</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3727	</pre>
				3728
				3729	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3730	<p>The '<tt>free</tt>' instruction returns memory back to the unused memory heap
				3731	to be reallocated in the future.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3732
				3733	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3734	<p>'<tt>value</tt>' shall be a pointer value that points to a value that was
				3735	allocated with the '<tt><a href="#i_malloc">malloc</a></tt>' instruction.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3736
				3737	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3738	<p>Access to the memory pointed to by the pointer is no longer defined after
				3739	this instruction executes. If the pointer is null, the operation is a
				3740	noop.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3741
				3742	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3743	<pre>
Dan Gohman	f54f50a	2009-01-04 23:49:44 +0000	[diff] [blame]	3744	%array = <a href="#i_malloc">malloc</a> [4 x i8] <i>; yields {[4 x i8]*}:array</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3745	free [4 x i8]* %array
				3746	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3747
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3748	</div>
				3749
				3750	<!-- _______________________________________________________________________ -->
				3751	<div class="doc_subsubsection">
				3752	<a name="i_alloca">'<tt>alloca</tt>' Instruction</a>
				3753	</div>
				3754
				3755	<div class="doc_text">
				3756
				3757	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3758	<pre>
				3759	<result> = alloca <type>[, i32 <NumElements>][, align <alignment>] <i>; yields {type*}:result</i>
				3760	</pre>
				3761
				3762	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3763	<p>The '<tt>alloca</tt>' instruction allocates memory on the stack frame of the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3764	currently executing function, to be automatically released when this function
				3765	returns to its caller. The object is always allocated in the generic address
				3766	space (address space zero).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3767
				3768	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3769	<p>The '<tt>alloca</tt>' instruction
				3770	allocates <tt>sizeof(<type>)*NumElements</tt> bytes of memory on the
				3771	runtime stack, returning a pointer of the appropriate type to the program.
				3772	If "NumElements" is specified, it is the number of elements allocated,
				3773	otherwise "NumElements" is defaulted to be one. If a constant alignment is
				3774	specified, the value result of the allocation is guaranteed to be aligned to
				3775	at least that boundary. If not specified, or if zero, the target can choose
				3776	to align the allocation on any convenient boundary compatible with the
				3777	type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3778
				3779	<p>'<tt>type</tt>' may be any sized type.</p>
				3780
				3781	<h5>Semantics:</h5>
Bill Wendling	2a45457	2009-05-08 20:49:29 +0000	[diff] [blame]	3782	<p>Memory is allocated; a pointer is returned. The operation is undefined if
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3783	there is insufficient stack space for the allocation. '<tt>alloca</tt>'d
				3784	memory is automatically released when the function returns. The
				3785	'<tt>alloca</tt>' instruction is commonly used to represent automatic
				3786	variables that must have an address available. When the function returns
				3787	(either with the <tt><a href="#i_ret">ret</a></tt>
				3788	or <tt><a href="#i_unwind">unwind</a></tt> instructions), the memory is
				3789	reclaimed. Allocating zero bytes is legal, but the result is undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3790
				3791	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3792	<pre>
Dan Gohman	f54f50a	2009-01-04 23:49:44 +0000	[diff] [blame]	3793	%ptr = alloca i32 <i>; yields {i32*}:ptr</i>
				3794	%ptr = alloca i32, i32 4 <i>; yields {i32*}:ptr</i>
				3795	%ptr = alloca i32, i32 4, align 1024 <i>; yields {i32*}:ptr</i>
				3796	%ptr = alloca i32, align 1024 <i>; yields {i32*}:ptr</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3797	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3798
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3799	</div>
				3800
				3801	<!-- _______________________________________________________________________ -->
				3802	<div class="doc_subsubsection"> <a name="i_load">'<tt>load</tt>'
				3803	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3804
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3805	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3806
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3807	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3808	<pre>
				3809	<result> = load <ty>* <pointer>[, align <alignment>]
				3810	<result> = volatile load <ty>* <pointer>[, align <alignment>]
				3811	</pre>
				3812
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3813	<h5>Overview:</h5>
				3814	<p>The '<tt>load</tt>' instruction is used to read from memory.</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3815
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3816	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3817	<p>The argument to the '<tt>load</tt>' instruction specifies the memory address
				3818	from which to load. The pointer must point to
				3819	a <a href="#t_firstclass">first class</a> type. If the <tt>load</tt> is
				3820	marked as <tt>volatile</tt>, then the optimizer is not allowed to modify the
				3821	number or order of execution of this <tt>load</tt> with other
				3822	volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
				3823	instructions. </p>
				3824
				3825	<p>The optional constant "align" argument specifies the alignment of the
				3826	operation (that is, the alignment of the memory address). A value of 0 or an
				3827	omitted "align" argument means that the operation has the preferential
				3828	alignment for the target. It is the responsibility of the code emitter to
				3829	ensure that the alignment information is correct. Overestimating the
				3830	alignment results in an undefined behavior. Underestimating the alignment may
				3831	produce less efficient code. An alignment of 1 is always safe.</p>
				3832
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3833	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3834	<p>The location of memory pointed to is loaded. If the value being loaded is of
				3835	scalar type then the number of bytes read does not exceed the minimum number
				3836	of bytes needed to hold all bits of the type. For example, loading an
				3837	<tt>i24</tt> reads at most three bytes. When loading a value of a type like
				3838	<tt>i20</tt> with a size that is not an integral number of bytes, the result
				3839	is undefined if the value was not originally written using a store of the
				3840	same type.</p>
				3841
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3842	<h5>Examples:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3843	<pre>
				3844	%ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
				3845	<a href="#i_store">store</a> i32 3, i32* %ptr <i>; yields {void}</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3846	%val = load i32* %ptr <i>; yields {i32}:val = i32 3</i>
				3847	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3848
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3849	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3850
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3851	<!-- _______________________________________________________________________ -->
				3852	<div class="doc_subsubsection"> <a name="i_store">'<tt>store</tt>'
				3853	Instruction</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3854
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3855	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3856
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3857	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3858	<pre>
				3859	store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3860	volatile store <ty> <value>, <ty>* <pointer>[, align <alignment>] <i>; yields {void}</i>
				3861	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3862
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3863	<h5>Overview:</h5>
				3864	<p>The '<tt>store</tt>' instruction is used to write to memory.</p>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3865
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3866	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3867	<p>There are two arguments to the '<tt>store</tt>' instruction: a value to store
				3868	and an address at which to store it. The type of the
				3869	'<tt><pointer></tt>' operand must be a pointer to
				3870	the <a href="#t_firstclass">first class</a> type of the
				3871	'<tt><value></tt>' operand. If the <tt>store</tt> is marked
				3872	as <tt>volatile</tt>, then the optimizer is not allowed to modify the number
				3873	or order of execution of this <tt>store</tt> with other
				3874	volatile <tt>load</tt> and <tt><a href="#i_store">store</a></tt>
				3875	instructions.</p>
				3876
				3877	<p>The optional constant "align" argument specifies the alignment of the
				3878	operation (that is, the alignment of the memory address). A value of 0 or an
				3879	omitted "align" argument means that the operation has the preferential
				3880	alignment for the target. It is the responsibility of the code emitter to
				3881	ensure that the alignment information is correct. Overestimating the
				3882	alignment results in an undefined behavior. Underestimating the alignment may
				3883	produce less efficient code. An alignment of 1 is always safe.</p>
				3884
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3885	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3886	<p>The contents of memory are updated to contain '<tt><value></tt>' at the
				3887	location specified by the '<tt><pointer></tt>' operand. If
				3888	'<tt><value></tt>' is of scalar type then the number of bytes written
				3889	does not exceed the minimum number of bytes needed to hold all bits of the
				3890	type. For example, storing an <tt>i24</tt> writes at most three bytes. When
				3891	writing a value of a type like <tt>i20</tt> with a size that is not an
				3892	integral number of bytes, it is unspecified what happens to the extra bits
				3893	that do not belong to the type, but they will typically be overwritten.</p>
				3894
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3895	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3896	<pre>
				3897	%ptr = <a href="#i_alloca">alloca</a> i32 <i>; yields {i32*}:ptr</i>
Bill Wendling	63ffa14	2007-10-22 05:10:05 +0000	[diff] [blame]	3898	store i32 3, i32* %ptr <i>; yields {void}</i>
				3899	%val = <a href="#i_load">load</a> i32* %ptr <i>; yields {i32}:val = i32 3</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3900	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3901
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3902	</div>
				3903
				3904	<!-- _______________________________________________________________________ -->
				3905	<div class="doc_subsubsection">
				3906	<a name="i_getelementptr">'<tt>getelementptr</tt>' Instruction</a>
				3907	</div>
				3908
				3909	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3910
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3911	<h5>Syntax:</h5>
				3912	<pre>
Matthijs Kooijman	32a080e	2008-10-13 13:44:15 +0000	[diff] [blame]	3913	<result> = getelementptr <pty>* <ptrval>{, <ty> <idx>}*
Dan Gohman	106b2ae	2009-07-27 21:53:46 +0000	[diff] [blame]	3914	<result> = getelementptr inbounds <pty>* <ptrval>{, <ty> <idx>}*
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3915	</pre>
				3916
				3917	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3918	<p>The '<tt>getelementptr</tt>' instruction is used to get the address of a
				3919	subelement of an aggregate data structure. It performs address calculation
				3920	only and does not access memory.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3921
				3922	<h5>Arguments:</h5>
Matthijs Kooijman	32a080e	2008-10-13 13:44:15 +0000	[diff] [blame]	3923	<p>The first argument is always a pointer, and forms the basis of the
Chris Lattner	e92fc83	2009-07-29 06:44:13 +0000	[diff] [blame]	3924	calculation. The remaining arguments are indices that indicate which of the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3925	elements of the aggregate object are indexed. The interpretation of each
				3926	index is dependent on the type being indexed into. The first index always
				3927	indexes the pointer value given as the first argument, the second index
				3928	indexes a value of the type pointed to (not necessarily the value directly
				3929	pointed to, since the first index can be non-zero), etc. The first type
				3930	indexed into must be a pointer value, subsequent types can be arrays, vectors
				3931	and structs. Note that subsequent types being indexed into can never be
				3932	pointers, since that would require loading the pointer before continuing
				3933	calculation.</p>
Matthijs Kooijman	32a080e	2008-10-13 13:44:15 +0000	[diff] [blame]	3934
				3935	<p>The type of each index argument depends on the type it is indexing into.
Chris Lattner	e92fc83	2009-07-29 06:44:13 +0000	[diff] [blame]	3936	When indexing into a (optionally packed) structure, only <tt>i32</tt> integer
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3937	<b>constants</b> are allowed. When indexing into an array, pointer or
Chris Lattner	e92fc83	2009-07-29 06:44:13 +0000	[diff] [blame]	3938	vector, integers of any width are allowed, and they are not required to be
				3939	constant.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3940
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3941	<p>For example, let's consider a C code fragment and how it gets compiled to
				3942	LLVM:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3943
				3944	<div class="doc_code">
				3945	<pre>
				3946	struct RT {
				3947	char A;
				3948	int B[10][20];
				3949	char C;
				3950	};
				3951	struct ST {
				3952	int X;
				3953	double Y;
				3954	struct RT Z;
				3955	};
				3956
				3957	int foo(struct ST s) {
				3958	return &s[1].Z.B[5][13];
				3959	}
				3960	</pre>
				3961	</div>
				3962
				3963	<p>The LLVM code generated by the GCC frontend is:</p>
				3964
				3965	<div class="doc_code">
				3966	<pre>
Chris Lattner	5b6dc6e	2009-01-11 20:53:49 +0000	[diff] [blame]	3967	%RT = <a href="#namedtypes">type</a> { i8 , [10 x [20 x i32]], i8 }
				3968	%ST = <a href="#namedtypes">type</a> { i32, double, %RT }
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3969
Dan Gohman	4736084	2009-07-25 02:23:48 +0000	[diff] [blame]	3970	define i32* @foo(%ST* %s) {
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3971	entry:
				3972	%reg = getelementptr %ST* %s, i32 1, i32 2, i32 1, i32 5, i32 13
				3973	ret i32* %reg
				3974	}
				3975	</pre>
				3976	</div>
				3977
				3978	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3979	<p>In the example above, the first index is indexing into the '<tt>%ST*</tt>'
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3980	type, which is a pointer, yielding a '<tt>%ST</tt>' = '<tt>{ i32, double, %RT
				3981	}</tt>' type, a structure. The second index indexes into the third element
				3982	of the structure, yielding a '<tt>%RT</tt>' = '<tt>{ i8 , [10 x [20 x i32]],
				3983	i8 }</tt>' type, another structure. The third index indexes into the second
				3984	element of the structure, yielding a '<tt>[10 x [20 x i32]]</tt>' type, an
				3985	array. The two dimensions of the array are subscripted into, yielding an
				3986	'<tt>i32</tt>' type. The '<tt>getelementptr</tt>' instruction returns a
				3987	pointer to this element, thus computing a value of '<tt>i32*</tt>' type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3988
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	3989	<p>Note that it is perfectly legal to index partially through a structure,
				3990	returning a pointer to an inner element. Because of this, the LLVM code for
				3991	the given testcase is equivalent to:</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3992
				3993	<pre>
Dan Gohman	4736084	2009-07-25 02:23:48 +0000	[diff] [blame]	3994	define i32* @foo(%ST* %s) {
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	3995	%t1 = getelementptr %ST* %s, i32 1 <i>; yields %ST*:%t1</i>
				3996	%t2 = getelementptr %ST* %t1, i32 0, i32 2 <i>; yields %RT*:%t2</i>
				3997	%t3 = getelementptr %RT* %t2, i32 0, i32 1 <i>; yields [10 x [20 x i32]]*:%t3</i>
				3998	%t4 = getelementptr [10 x [20 x i32]]* %t3, i32 0, i32 5 <i>; yields [20 x i32]*:%t4</i>
				3999	%t5 = getelementptr [20 x i32]* %t4, i32 0, i32 13 <i>; yields i32*:%t5</i>
				4000	ret i32* %t5
				4001	}
				4002	</pre>
				4003
Dan Gohman	106b2ae	2009-07-27 21:53:46 +0000	[diff] [blame]	4004	<p>If the <tt>inbounds</tt> keyword is present, the result value of the
Dan Gohman	4cba156	2009-07-29 16:00:30 +0000	[diff] [blame]	4005	<tt>getelementptr</tt> is undefined if the base pointer is not an
				4006	<i>in bounds</i> address of an allocated object, or if any of the addresses
Dan Gohman	bc4c87f	2009-08-20 17:08:17 +0000	[diff] [blame^]	4007	that would be formed by successive addition of the offsets implied by the
				4008	indices to the base address with infinitely precise arithmetic are not an
				4009	<i>in bounds</i> address of that allocated object.
Dan Gohman	4cba156	2009-07-29 16:00:30 +0000	[diff] [blame]	4010	The <i>in bounds</i> addresses for an allocated object are all the addresses
Dan Gohman	bc4c87f	2009-08-20 17:08:17 +0000	[diff] [blame^]	4011	that point into the object, plus the address one byte past the end.</p>
Dan Gohman	106b2ae	2009-07-27 21:53:46 +0000	[diff] [blame]	4012
				4013	<p>If the <tt>inbounds</tt> keyword is not present, the offsets are added to
				4014	the base address with silently-wrapping two's complement arithmetic, and
				4015	the result value of the <tt>getelementptr</tt> may be outside the object
				4016	pointed to by the base pointer. The result value may not necessarily be
				4017	used to access memory though, even if it happens to point into allocated
				4018	storage. See the <a href="#pointeraliasing">Pointer Aliasing Rules</a>
				4019	section for more information.</p>
				4020
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4021	<p>The getelementptr instruction is often confusing. For some more insight into
				4022	how it works, see <a href="GetElementPtr.html">the getelementptr FAQ</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4023
				4024	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4025	<pre>
				4026	<i>; yields [12 x i8]*:aptr</i>
Matthijs Kooijman	32a080e	2008-10-13 13:44:15 +0000	[diff] [blame]	4027	%aptr = getelementptr {i32, [12 x i8]}* %saptr, i64 0, i32 1
				4028	<i>; yields i8*:vptr</i>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	4029	%vptr = getelementptr {i32, <2 x i8>}* %svptr, i64 0, i32 1, i32 1
Matthijs Kooijman	32a080e	2008-10-13 13:44:15 +0000	[diff] [blame]	4030	<i>; yields i8*:eptr</i>
				4031	%eptr = getelementptr [12 x i8]* %aptr, i64 0, i32 1
Sanjiv Gupta	4f9a0dc	2009-04-25 07:27:44 +0000	[diff] [blame]	4032	<i>; yields i32*:iptr</i>
Sanjiv Gupta	1e46c58	2009-04-24 16:38:13 +0000	[diff] [blame]	4033	%iptr = getelementptr [10 x i32]* @arr, i16 0, i16 0
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4034	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4035
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4036	</div>
				4037
				4038	<!-- ======================================================================= -->
				4039	<div class="doc_subsection"> <a name="convertops">Conversion Operations</a>
				4040	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4041
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4042	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4043
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4044	<p>The instructions in this category are the conversion instructions (casting)
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4045	which all take a single operand and a type. They perform various bit
				4046	conversions on the operand.</p>
				4047
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4048	</div>
				4049
				4050	<!-- _______________________________________________________________________ -->
				4051	<div class="doc_subsubsection">
				4052	<a name="i_trunc">'<tt>trunc .. to</tt>' Instruction</a>
				4053	</div>
				4054	<div class="doc_text">
				4055
				4056	<h5>Syntax:</h5>
				4057	<pre>
				4058	<result> = trunc <ty> <value> to <ty2> <i>; yields ty2</i>
				4059	</pre>
				4060
				4061	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4062	<p>The '<tt>trunc</tt>' instruction truncates its operand to the
				4063	type <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4064
				4065	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4066	<p>The '<tt>trunc</tt>' instruction takes a <tt>value</tt> to trunc, which must
				4067	be an <a href="#t_integer">integer</a> type, and a type that specifies the
				4068	size and type of the result, which must be
				4069	an <a href="#t_integer">integer</a> type. The bit size of <tt>value</tt> must
				4070	be larger than the bit size of <tt>ty2</tt>. Equal sized types are not
				4071	allowed.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4072
				4073	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4074	<p>The '<tt>trunc</tt>' instruction truncates the high order bits
				4075	in <tt>value</tt> and converts the remaining bits to <tt>ty2</tt>. Since the
				4076	source size must be larger than the destination size, <tt>trunc</tt> cannot
				4077	be a <i>no-op cast</i>. It will always truncate bits.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4078
				4079	<h5>Example:</h5>
				4080	<pre>
				4081	%X = trunc i32 257 to i8 <i>; yields i8:1</i>
				4082	%Y = trunc i32 123 to i1 <i>; yields i1:true</i>
				4083	%Y = trunc i32 122 to i1 <i>; yields i1:false</i>
				4084	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4085
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4086	</div>
				4087
				4088	<!-- _______________________________________________________________________ -->
				4089	<div class="doc_subsubsection">
				4090	<a name="i_zext">'<tt>zext .. to</tt>' Instruction</a>
				4091	</div>
				4092	<div class="doc_text">
				4093
				4094	<h5>Syntax:</h5>
				4095	<pre>
				4096	<result> = zext <ty> <value> to <ty2> <i>; yields ty2</i>
				4097	</pre>
				4098
				4099	<h5>Overview:</h5>
				4100	<p>The '<tt>zext</tt>' instruction zero extends its operand to type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4101	<tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4102
				4103
				4104	<h5>Arguments:</h5>
				4105	<p>The '<tt>zext</tt>' instruction takes a value to cast, which must be of
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4106	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				4107	also be of <a href="#t_integer">integer</a> type. The bit size of the
				4108	<tt>value</tt> must be smaller than the bit size of the destination type,
				4109	<tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4110
				4111	<h5>Semantics:</h5>
				4112	<p>The <tt>zext</tt> fills the high order bits of the <tt>value</tt> with zero
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4113	bits until it reaches the size of the destination type, <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4114
				4115	<p>When zero extending from i1, the result will always be either 0 or 1.</p>
				4116
				4117	<h5>Example:</h5>
				4118	<pre>
				4119	%X = zext i32 257 to i64 <i>; yields i64:257</i>
				4120	%Y = zext i1 true to i32 <i>; yields i32:1</i>
				4121	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4122
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4123	</div>
				4124
				4125	<!-- _______________________________________________________________________ -->
				4126	<div class="doc_subsubsection">
				4127	<a name="i_sext">'<tt>sext .. to</tt>' Instruction</a>
				4128	</div>
				4129	<div class="doc_text">
				4130
				4131	<h5>Syntax:</h5>
				4132	<pre>
				4133	<result> = sext <ty> <value> to <ty2> <i>; yields ty2</i>
				4134	</pre>
				4135
				4136	<h5>Overview:</h5>
				4137	<p>The '<tt>sext</tt>' sign extends <tt>value</tt> to the type <tt>ty2</tt>.</p>
				4138
				4139	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4140	<p>The '<tt>sext</tt>' instruction takes a value to cast, which must be of
				4141	<a href="#t_integer">integer</a> type, and a type to cast it to, which must
				4142	also be of <a href="#t_integer">integer</a> type. The bit size of the
				4143	<tt>value</tt> must be smaller than the bit size of the destination type,
				4144	<tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4145
				4146	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4147	<p>The '<tt>sext</tt>' instruction performs a sign extension by copying the sign
				4148	bit (highest order bit) of the <tt>value</tt> until it reaches the bit size
				4149	of the type <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4150
				4151	<p>When sign extending from i1, the extension always results in -1 or 0.</p>
				4152
				4153	<h5>Example:</h5>
				4154	<pre>
				4155	%X = sext i8 -1 to i16 <i>; yields i16 :65535</i>
				4156	%Y = sext i1 true to i32 <i>; yields i32:-1</i>
				4157	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4158
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4159	</div>
				4160
				4161	<!-- _______________________________________________________________________ -->
				4162	<div class="doc_subsubsection">
				4163	<a name="i_fptrunc">'<tt>fptrunc .. to</tt>' Instruction</a>
				4164	</div>
				4165
				4166	<div class="doc_text">
				4167
				4168	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4169	<pre>
				4170	<result> = fptrunc <ty> <value> to <ty2> <i>; yields ty2</i>
				4171	</pre>
				4172
				4173	<h5>Overview:</h5>
				4174	<p>The '<tt>fptrunc</tt>' instruction truncates <tt>value</tt> to type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4175	<tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4176
				4177	<h5>Arguments:</h5>
				4178	<p>The '<tt>fptrunc</tt>' instruction takes a <a href="#t_floating">floating
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4179	point</a> value to cast and a <a href="#t_floating">floating point</a> type
				4180	to cast it to. The size of <tt>value</tt> must be larger than the size of
				4181	<tt>ty2</tt>. This implies that <tt>fptrunc</tt> cannot be used to make a
				4182	<i>no-op cast</i>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4183
				4184	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4185	<p>The '<tt>fptrunc</tt>' instruction truncates a <tt>value</tt> from a larger
				4186	<a href="#t_floating">floating point</a> type to a smaller
				4187	<a href="#t_floating">floating point</a> type. If the value cannot fit
				4188	within the destination type, <tt>ty2</tt>, then the results are
				4189	undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4190
				4191	<h5>Example:</h5>
				4192	<pre>
				4193	%X = fptrunc double 123.0 to float <i>; yields float:123.0</i>
				4194	%Y = fptrunc double 1.0E+300 to float <i>; yields undefined</i>
				4195	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4196
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4197	</div>
				4198
				4199	<!-- _______________________________________________________________________ -->
				4200	<div class="doc_subsubsection">
				4201	<a name="i_fpext">'<tt>fpext .. to</tt>' Instruction</a>
				4202	</div>
				4203	<div class="doc_text">
				4204
				4205	<h5>Syntax:</h5>
				4206	<pre>
				4207	<result> = fpext <ty> <value> to <ty2> <i>; yields ty2</i>
				4208	</pre>
				4209
				4210	<h5>Overview:</h5>
				4211	<p>The '<tt>fpext</tt>' extends a floating point <tt>value</tt> to a larger
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4212	floating point value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4213
				4214	<h5>Arguments:</h5>
				4215	<p>The '<tt>fpext</tt>' instruction takes a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4216	<a href="#t_floating">floating point</a> <tt>value</tt> to cast, and
				4217	a <a href="#t_floating">floating point</a> type to cast it to. The source
				4218	type must be smaller than the destination type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4219
				4220	<h5>Semantics:</h5>
				4221	<p>The '<tt>fpext</tt>' instruction extends the <tt>value</tt> from a smaller
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4222	<a href="#t_floating">floating point</a> type to a larger
				4223	<a href="#t_floating">floating point</a> type. The <tt>fpext</tt> cannot be
				4224	used to make a <i>no-op cast</i> because it always changes bits. Use
				4225	<tt>bitcast</tt> to make a <i>no-op cast</i> for a floating point cast.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4226
				4227	<h5>Example:</h5>
				4228	<pre>
				4229	%X = fpext float 3.1415 to double <i>; yields double:3.1415</i>
				4230	%Y = fpext float 1.0 to float <i>; yields float:1.0 (no-op)</i>
				4231	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4232
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4233	</div>
				4234
				4235	<!-- _______________________________________________________________________ -->
				4236	<div class="doc_subsubsection">
				4237	<a name="i_fptoui">'<tt>fptoui .. to</tt>' Instruction</a>
				4238	</div>
				4239	<div class="doc_text">
				4240
				4241	<h5>Syntax:</h5>
				4242	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	4243	<result> = fptoui <ty> <value> to <ty2> <i>; yields ty2</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4244	</pre>
				4245
				4246	<h5>Overview:</h5>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	4247	<p>The '<tt>fptoui</tt>' converts a floating point <tt>value</tt> to its
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4248	unsigned integer equivalent of type <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4249
				4250	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4251	<p>The '<tt>fptoui</tt>' instruction takes a value to cast, which must be a
				4252	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				4253	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				4254	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				4255	vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4256
				4257	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4258	<p>The '<tt>fptoui</tt>' instruction converts its
				4259	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				4260	towards zero) unsigned integer value. If the value cannot fit
				4261	in <tt>ty2</tt>, the results are undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4262
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4263	<h5>Example:</h5>
				4264	<pre>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	4265	%X = fptoui double 123.0 to i32 <i>; yields i32:123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	4266	%Y = fptoui float 1.0E+300 to i1 <i>; yields undefined:1</i>
Reid Spencer	e6adee8	2007-07-31 14:40:14 +0000	[diff] [blame]	4267	%X = fptoui float 1.04E+17 to i8 <i>; yields undefined:1</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4268	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4269
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4270	</div>
				4271
				4272	<!-- _______________________________________________________________________ -->
				4273	<div class="doc_subsubsection">
				4274	<a name="i_fptosi">'<tt>fptosi .. to</tt>' Instruction</a>
				4275	</div>
				4276	<div class="doc_text">
				4277
				4278	<h5>Syntax:</h5>
				4279	<pre>
				4280	<result> = fptosi <ty> <value> to <ty2> <i>; yields ty2</i>
				4281	</pre>
				4282
				4283	<h5>Overview:</h5>
				4284	<p>The '<tt>fptosi</tt>' instruction converts
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4285	<a href="#t_floating">floating point</a> <tt>value</tt> to
				4286	type <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4287
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4288	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4289	<p>The '<tt>fptosi</tt>' instruction takes a value to cast, which must be a
				4290	scalar or vector <a href="#t_floating">floating point</a> value, and a type
				4291	to cast it to <tt>ty2</tt>, which must be an <a href="#t_integer">integer</a>
				4292	type. If <tt>ty</tt> is a vector floating point type, <tt>ty2</tt> must be a
				4293	vector integer type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4294
				4295	<h5>Semantics:</h5>
				4296	<p>The '<tt>fptosi</tt>' instruction converts its
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4297	<a href="#t_floating">floating point</a> operand into the nearest (rounding
				4298	towards zero) signed integer value. If the value cannot fit in <tt>ty2</tt>,
				4299	the results are undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4300
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4301	<h5>Example:</h5>
				4302	<pre>
				4303	%X = fptosi double -123.0 to i32 <i>; yields i32:-123</i>
Chris Lattner	681f1e8	2007-09-22 03:17:52 +0000	[diff] [blame]	4304	%Y = fptosi float 1.0E-247 to i1 <i>; yields undefined:1</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4305	%X = fptosi float 1.04E+17 to i8 <i>; yields undefined:1</i>
				4306	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4307
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4308	</div>
				4309
				4310	<!-- _______________________________________________________________________ -->
				4311	<div class="doc_subsubsection">
				4312	<a name="i_uitofp">'<tt>uitofp .. to</tt>' Instruction</a>
				4313	</div>
				4314	<div class="doc_text">
				4315
				4316	<h5>Syntax:</h5>
				4317	<pre>
				4318	<result> = uitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				4319	</pre>
				4320
				4321	<h5>Overview:</h5>
				4322	<p>The '<tt>uitofp</tt>' instruction regards <tt>value</tt> as an unsigned
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4323	integer and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4324
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4325	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	4326	<p>The '<tt>uitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4327	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
				4328	it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				4329	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				4330	floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4331
				4332	<h5>Semantics:</h5>
				4333	<p>The '<tt>uitofp</tt>' instruction interprets its operand as an unsigned
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4334	integer quantity and converts it to the corresponding floating point
				4335	value. If the value cannot fit in the floating point value, the results are
				4336	undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4337
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4338	<h5>Example:</h5>
				4339	<pre>
				4340	%X = uitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	4341	%Y = uitofp i8 -1 to double <i>; yields double:255.0</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4342	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4343
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4344	</div>
				4345
				4346	<!-- _______________________________________________________________________ -->
				4347	<div class="doc_subsubsection">
				4348	<a name="i_sitofp">'<tt>sitofp .. to</tt>' Instruction</a>
				4349	</div>
				4350	<div class="doc_text">
				4351
				4352	<h5>Syntax:</h5>
				4353	<pre>
				4354	<result> = sitofp <ty> <value> to <ty2> <i>; yields ty2</i>
				4355	</pre>
				4356
				4357	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4358	<p>The '<tt>sitofp</tt>' instruction regards <tt>value</tt> as a signed integer
				4359	and converts that value to the <tt>ty2</tt> type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4360
				4361	<h5>Arguments:</h5>
Nate Begeman	78246ca	2007-11-17 03:58:34 +0000	[diff] [blame]	4362	<p>The '<tt>sitofp</tt>' instruction takes a value to cast, which must be a
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4363	scalar or vector <a href="#t_integer">integer</a> value, and a type to cast
				4364	it to <tt>ty2</tt>, which must be an <a href="#t_floating">floating point</a>
				4365	type. If <tt>ty</tt> is a vector integer type, <tt>ty2</tt> must be a vector
				4366	floating point type with the same number of elements as <tt>ty</tt></p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4367
				4368	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4369	<p>The '<tt>sitofp</tt>' instruction interprets its operand as a signed integer
				4370	quantity and converts it to the corresponding floating point value. If the
				4371	value cannot fit in the floating point value, the results are undefined.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4372
				4373	<h5>Example:</h5>
				4374	<pre>
				4375	%X = sitofp i32 257 to float <i>; yields float:257.0</i>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	4376	%Y = sitofp i8 -1 to double <i>; yields double:-1.0</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4377	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4378
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4379	</div>
				4380
				4381	<!-- _______________________________________________________________________ -->
				4382	<div class="doc_subsubsection">
				4383	<a name="i_ptrtoint">'<tt>ptrtoint .. to</tt>' Instruction</a>
				4384	</div>
				4385	<div class="doc_text">
				4386
				4387	<h5>Syntax:</h5>
				4388	<pre>
				4389	<result> = ptrtoint <ty> <value> to <ty2> <i>; yields ty2</i>
				4390	</pre>
				4391
				4392	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4393	<p>The '<tt>ptrtoint</tt>' instruction converts the pointer <tt>value</tt> to
				4394	the integer type <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4395
				4396	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4397	<p>The '<tt>ptrtoint</tt>' instruction takes a <tt>value</tt> to cast, which
				4398	must be a <a href="#t_pointer">pointer</a> value, and a type to cast it to
				4399	<tt>ty2</tt>, which must be an <a href="#t_integer">integer</a> type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4400
				4401	<h5>Semantics:</h5>
				4402	<p>The '<tt>ptrtoint</tt>' instruction converts <tt>value</tt> to integer type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4403	<tt>ty2</tt> by interpreting the pointer value as an integer and either
				4404	truncating or zero extending that value to the size of the integer type. If
				4405	<tt>value</tt> is smaller than <tt>ty2</tt> then a zero extension is done. If
				4406	<tt>value</tt> is larger than <tt>ty2</tt> then a truncation is done. If they
				4407	are the same size, then nothing is done (<i>no-op cast</i>) other than a type
				4408	change.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4409
				4410	<h5>Example:</h5>
				4411	<pre>
				4412	%X = ptrtoint i32* %X to i8 <i>; yields truncation on 32-bit architecture</i>
				4413	%Y = ptrtoint i32* %x to i64 <i>; yields zero extension on 32-bit architecture</i>
				4414	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4415
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4416	</div>
				4417
				4418	<!-- _______________________________________________________________________ -->
				4419	<div class="doc_subsubsection">
				4420	<a name="i_inttoptr">'<tt>inttoptr .. to</tt>' Instruction</a>
				4421	</div>
				4422	<div class="doc_text">
				4423
				4424	<h5>Syntax:</h5>
				4425	<pre>
				4426	<result> = inttoptr <ty> <value> to <ty2> <i>; yields ty2</i>
				4427	</pre>
				4428
				4429	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4430	<p>The '<tt>inttoptr</tt>' instruction converts an integer <tt>value</tt> to a
				4431	pointer type, <tt>ty2</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4432
				4433	<h5>Arguments:</h5>
				4434	<p>The '<tt>inttoptr</tt>' instruction takes an <a href="#t_integer">integer</a>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4435	value to cast, and a type to cast it to, which must be a
				4436	<a href="#t_pointer">pointer</a> type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4437
				4438	<h5>Semantics:</h5>
				4439	<p>The '<tt>inttoptr</tt>' instruction converts <tt>value</tt> to type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4440	<tt>ty2</tt> by applying either a zero extension or a truncation depending on
				4441	the size of the integer <tt>value</tt>. If <tt>value</tt> is larger than the
				4442	size of a pointer then a truncation is done. If <tt>value</tt> is smaller
				4443	than the size of a pointer then a zero extension is done. If they are the
				4444	same size, nothing is done (<i>no-op cast</i>).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4445
				4446	<h5>Example:</h5>
				4447	<pre>
				4448	%X = inttoptr i32 255 to i32* <i>; yields zero extension on 64-bit architecture</i>
				4449	%X = inttoptr i32 255 to i32* <i>; yields no-op on 32-bit architecture</i>
				4450	%Y = inttoptr i64 0 to i32* <i>; yields truncation on 32-bit architecture</i>
				4451	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4452
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4453	</div>
				4454
				4455	<!-- _______________________________________________________________________ -->
				4456	<div class="doc_subsubsection">
				4457	<a name="i_bitcast">'<tt>bitcast .. to</tt>' Instruction</a>
				4458	</div>
				4459	<div class="doc_text">
				4460
				4461	<h5>Syntax:</h5>
				4462	<pre>
				4463	<result> = bitcast <ty> <value> to <ty2> <i>; yields ty2</i>
				4464	</pre>
				4465
				4466	<h5>Overview:</h5>
				4467	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4468	<tt>ty2</tt> without changing any bits.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4469
				4470	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4471	<p>The '<tt>bitcast</tt>' instruction takes a value to cast, which must be a
				4472	non-aggregate first class value, and a type to cast it to, which must also be
				4473	a non-aggregate <a href="#t_firstclass">first class</a> type. The bit sizes
				4474	of <tt>value</tt> and the destination type, <tt>ty2</tt>, must be
				4475	identical. If the source type is a pointer, the destination type must also be
				4476	a pointer. This instruction supports bitwise conversion of vectors to
				4477	integers and to vectors of other types (as long as they have the same
				4478	size).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4479
				4480	<h5>Semantics:</h5>
				4481	<p>The '<tt>bitcast</tt>' instruction converts <tt>value</tt> to type
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4482	<tt>ty2</tt>. It is always a <i>no-op cast</i> because no bits change with
				4483	this conversion. The conversion is done as if the <tt>value</tt> had been
				4484	stored to memory and read back as type <tt>ty2</tt>. Pointer types may only
				4485	be converted to other pointer types with this instruction. To convert
				4486	pointers to other types, use the <a href="#i_inttoptr">inttoptr</a> or
				4487	<a href="#i_ptrtoint">ptrtoint</a> instructions first.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4488
				4489	<h5>Example:</h5>
				4490	<pre>
				4491	%X = bitcast i8 255 to i8 <i>; yields i8 :-1</i>
				4492	%Y = bitcast i32* %x to sint* <i>; yields sint*:%x</i>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	4493	%Z = bitcast <2 x int> %V to i64; <i>; yields i64: %V</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4494	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4495
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4496	</div>
				4497
				4498	<!-- ======================================================================= -->
				4499	<div class="doc_subsection"> <a name="otherops">Other Operations</a> </div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4500
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4501	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4502
				4503	<p>The instructions in this category are the "miscellaneous" instructions, which
				4504	defy better classification.</p>
				4505
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4506	</div>
				4507
				4508	<!-- _______________________________________________________________________ -->
				4509	<div class="doc_subsubsection"><a name="i_icmp">'<tt>icmp</tt>' Instruction</a>
				4510	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4511
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4512	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4513
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4514	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4515	<pre>
				4516	<result> = icmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1>}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4517	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4518
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4519	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4520	<p>The '<tt>icmp</tt>' instruction returns a boolean value or a vector of
				4521	boolean values based on comparison of its two integer, integer vector, or
				4522	pointer operands.</p>
				4523
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4524	<h5>Arguments:</h5>
				4525	<p>The '<tt>icmp</tt>' instruction takes three operands. The first operand is
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4526	the condition code indicating the kind of comparison to perform. It is not a
				4527	value, just a keyword. The possible condition code are:</p>
				4528
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4529	<ol>
				4530	<li><tt>eq</tt>: equal</li>
				4531	<li><tt>ne</tt>: not equal </li>
				4532	<li><tt>ugt</tt>: unsigned greater than</li>
				4533	<li><tt>uge</tt>: unsigned greater or equal</li>
				4534	<li><tt>ult</tt>: unsigned less than</li>
				4535	<li><tt>ule</tt>: unsigned less or equal</li>
				4536	<li><tt>sgt</tt>: signed greater than</li>
				4537	<li><tt>sge</tt>: signed greater or equal</li>
				4538	<li><tt>slt</tt>: signed less than</li>
				4539	<li><tt>sle</tt>: signed less or equal</li>
				4540	</ol>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4541
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4542	<p>The remaining two arguments must be <a href="#t_integer">integer</a> or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4543	<a href="#t_pointer">pointer</a> or integer <a href="#t_vector">vector</a>
				4544	typed. They must also be identical types.</p>
				4545
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4546	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4547	<p>The '<tt>icmp</tt>' compares <tt>op1</tt> and <tt>op2</tt> according to the
				4548	condition code given as <tt>cond</tt>. The comparison performed always yields
				4549	either an <a href="#t_primitive"><tt>i1</tt></a> or vector of <tt>i1</tt>
				4550	result, as follows:</p>
				4551
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4552	<ol>
				4553	<li><tt>eq</tt>: yields <tt>true</tt> if the operands are equal,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4554	<tt>false</tt> otherwise. No sign interpretation is necessary or
				4555	performed.</li>
				4556
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4557	<li><tt>ne</tt>: yields <tt>true</tt> if the operands are unequal,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4558	<tt>false</tt> otherwise. No sign interpretation is necessary or
				4559	performed.</li>
				4560
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4561	<li><tt>ugt</tt>: interprets the operands as unsigned values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4562	<tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
				4563
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4564	<li><tt>uge</tt>: interprets the operands as unsigned values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4565	<tt>true</tt> if <tt>op1</tt> is greater than or equal
				4566	to <tt>op2</tt>.</li>
				4567
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4568	<li><tt>ult</tt>: interprets the operands as unsigned values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4569	<tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
				4570
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4571	<li><tt>ule</tt>: interprets the operands as unsigned values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4572	<tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
				4573
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4574	<li><tt>sgt</tt>: interprets the operands as signed values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4575	<tt>true</tt> if <tt>op1</tt> is greater than <tt>op2</tt>.</li>
				4576
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4577	<li><tt>sge</tt>: interprets the operands as signed values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4578	<tt>true</tt> if <tt>op1</tt> is greater than or equal
				4579	to <tt>op2</tt>.</li>
				4580
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4581	<li><tt>slt</tt>: interprets the operands as signed values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4582	<tt>true</tt> if <tt>op1</tt> is less than <tt>op2</tt>.</li>
				4583
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4584	<li><tt>sle</tt>: interprets the operands as signed values and yields
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4585	<tt>true</tt> if <tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4586	</ol>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4587
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4588	<p>If the operands are <a href="#t_pointer">pointer</a> typed, the pointer
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4589	values are compared as if they were integers.</p>
				4590
				4591	<p>If the operands are integer vectors, then they are compared element by
				4592	element. The result is an <tt>i1</tt> vector with the same number of elements
				4593	as the values being compared. Otherwise, the result is an <tt>i1</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4594
				4595	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4596	<pre>
				4597	<result> = icmp eq i32 4, 5 <i>; yields: result=false</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4598	<result> = icmp ne float* %X, %X <i>; yields: result=false</i>
				4599	<result> = icmp ult i16 4, 5 <i>; yields: result=true</i>
				4600	<result> = icmp sgt i16 4, 5 <i>; yields: result=false</i>
				4601	<result> = icmp ule i16 -4, 5 <i>; yields: result=false</i>
				4602	<result> = icmp sge i16 4, 5 <i>; yields: result=false</i>
				4603	</pre>
Dan Gohman	a53eb38	2009-01-22 01:39:38 +0000	[diff] [blame]	4604
				4605	<p>Note that the code generator does not yet support vector types with
				4606	the <tt>icmp</tt> instruction.</p>
				4607
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4608	</div>
				4609
				4610	<!-- _______________________________________________________________________ -->
				4611	<div class="doc_subsubsection"><a name="i_fcmp">'<tt>fcmp</tt>' Instruction</a>
				4612	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4613
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4614	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4615
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4616	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4617	<pre>
				4618	<result> = fcmp <cond> <ty> <op1>, <op2> <i>; yields {i1} or {<N x i1>}:result</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4619	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4620
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4621	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4622	<p>The '<tt>fcmp</tt>' instruction returns a boolean value or vector of boolean
				4623	values based on comparison of its operands.</p>
				4624
				4625	<p>If the operands are floating point scalars, then the result type is a boolean
				4626	(<a href="#t_primitive"><tt>i1</tt></a>).</p>
				4627
				4628	<p>If the operands are floating point vectors, then the result type is a vector
				4629	of boolean with the same number of elements as the operands being
				4630	compared.</p>
				4631
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4632	<h5>Arguments:</h5>
				4633	<p>The '<tt>fcmp</tt>' instruction takes three operands. The first operand is
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4634	the condition code indicating the kind of comparison to perform. It is not a
				4635	value, just a keyword. The possible condition code are:</p>
				4636
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4637	<ol>
				4638	<li><tt>false</tt>: no comparison, always returns false</li>
				4639	<li><tt>oeq</tt>: ordered and equal</li>
				4640	<li><tt>ogt</tt>: ordered and greater than </li>
				4641	<li><tt>oge</tt>: ordered and greater than or equal</li>
				4642	<li><tt>olt</tt>: ordered and less than </li>
				4643	<li><tt>ole</tt>: ordered and less than or equal</li>
				4644	<li><tt>one</tt>: ordered and not equal</li>
				4645	<li><tt>ord</tt>: ordered (no nans)</li>
				4646	<li><tt>ueq</tt>: unordered or equal</li>
				4647	<li><tt>ugt</tt>: unordered or greater than </li>
				4648	<li><tt>uge</tt>: unordered or greater than or equal</li>
				4649	<li><tt>ult</tt>: unordered or less than </li>
				4650	<li><tt>ule</tt>: unordered or less than or equal</li>
				4651	<li><tt>une</tt>: unordered or not equal</li>
				4652	<li><tt>uno</tt>: unordered (either nans)</li>
				4653	<li><tt>true</tt>: no comparison, always returns true</li>
				4654	</ol>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4655
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4656	<p><i>Ordered</i> means that neither operand is a QNAN while
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4657	<i>unordered</i> means that either operand may be a QNAN.</p>
				4658
				4659	<p>Each of <tt>val1</tt> and <tt>val2</tt> arguments must be either
				4660	a <a href="#t_floating">floating point</a> type or
				4661	a <a href="#t_vector">vector</a> of floating point type. They must have
				4662	identical types.</p>
				4663
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4664	<h5>Semantics:</h5>
Gabor Greif	d9068fe	2008-08-07 21:46:00 +0000	[diff] [blame]	4665	<p>The '<tt>fcmp</tt>' instruction compares <tt>op1</tt> and <tt>op2</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4666	according to the condition code given as <tt>cond</tt>. If the operands are
				4667	vectors, then the vectors are compared element by element. Each comparison
				4668	performed always yields an <a href="#t_primitive">i1</a> result, as
				4669	follows:</p>
				4670
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4671	<ol>
				4672	<li><tt>false</tt>: always yields <tt>false</tt>, regardless of operands.</li>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4673
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4674	<li><tt>oeq</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4675	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
				4676
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4677	<li><tt>ogt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4678	<tt>op1</tt> is greather than <tt>op2</tt>.</li>
				4679
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4680	<li><tt>oge</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4681	<tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
				4682
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4683	<li><tt>olt</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4684	<tt>op1</tt> is less than <tt>op2</tt>.</li>
				4685
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4686	<li><tt>ole</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4687	<tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
				4688
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4689	<li><tt>one</tt>: yields <tt>true</tt> if both operands are not a QNAN and
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4690	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
				4691
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4692	<li><tt>ord</tt>: yields <tt>true</tt> if both operands are not a QNAN.</li>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4693
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4694	<li><tt>ueq</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4695	<tt>op1</tt> is equal to <tt>op2</tt>.</li>
				4696
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4697	<li><tt>ugt</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4698	<tt>op1</tt> is greater than <tt>op2</tt>.</li>
				4699
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4700	<li><tt>uge</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4701	<tt>op1</tt> is greater than or equal to <tt>op2</tt>.</li>
				4702
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4703	<li><tt>ult</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4704	<tt>op1</tt> is less than <tt>op2</tt>.</li>
				4705
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4706	<li><tt>ule</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4707	<tt>op1</tt> is less than or equal to <tt>op2</tt>.</li>
				4708
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4709	<li><tt>une</tt>: yields <tt>true</tt> if either operand is a QNAN or
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4710	<tt>op1</tt> is not equal to <tt>op2</tt>.</li>
				4711
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4712	<li><tt>uno</tt>: yields <tt>true</tt> if either operand is a QNAN.</li>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4713
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4714	<li><tt>true</tt>: always yields <tt>true</tt>, regardless of operands.</li>
				4715	</ol>
				4716
				4717	<h5>Example:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4718	<pre>
				4719	<result> = fcmp oeq float 4.0, 5.0 <i>; yields: result=false</i>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4720	<result> = fcmp one float 4.0, 5.0 <i>; yields: result=true</i>
				4721	<result> = fcmp olt float 4.0, 5.0 <i>; yields: result=true</i>
				4722	<result> = fcmp ueq double 1.0, 2.0 <i>; yields: result=false</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4723	</pre>
Dan Gohman	a53eb38	2009-01-22 01:39:38 +0000	[diff] [blame]	4724
				4725	<p>Note that the code generator does not yet support vector types with
				4726	the <tt>fcmp</tt> instruction.</p>
				4727
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4728	</div>
				4729
				4730	<!-- _______________________________________________________________________ -->
Nate Begeman	646fa48	2008-05-12 19:01:56 +0000	[diff] [blame]	4731	<div class="doc_subsubsection">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4732	<a name="i_phi">'<tt>phi</tt>' Instruction</a>
				4733	</div>
				4734
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4735	<div class="doc_text">
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4736
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4737	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4738	<pre>
				4739	<result> = phi <ty> [ <val0>, <label0>], ...
				4740	</pre>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4741
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4742	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4743	<p>The '<tt>phi</tt>' instruction is used to implement the φ node in the
				4744	SSA graph representing the function.</p>
				4745
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4746	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4747	<p>The type of the incoming values is specified with the first type field. After
				4748	this, the '<tt>phi</tt>' instruction takes a list of pairs as arguments, with
				4749	one pair for each predecessor basic block of the current block. Only values
				4750	of <a href="#t_firstclass">first class</a> type may be used as the value
				4751	arguments to the PHI node. Only labels may be used as the label
				4752	arguments.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4753
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4754	<p>There must be no non-phi instructions between the start of a basic block and
				4755	the PHI instructions: i.e. PHI instructions must be first in a basic
				4756	block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4757
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4758	<p>For the purposes of the SSA form, the use of each incoming value is deemed to
				4759	occur on the edge from the corresponding predecessor block to the current
				4760	block (but after any definition of an '<tt>invoke</tt>' instruction's return
				4761	value on the same edge).</p>
Jay Foad	8e2fd2c	2009-06-03 10:20:10 +0000	[diff] [blame]	4762
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4763	<h5>Semantics:</h5>
				4764	<p>At runtime, the '<tt>phi</tt>' instruction logically takes on the value
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4765	specified by the pair corresponding to the predecessor basic block that
				4766	executed just prior to the current block.</p>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4767
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4768	<h5>Example:</h5>
Chris Lattner	6704c21	2008-05-20 20:48:21 +0000	[diff] [blame]	4769	<pre>
				4770	Loop: ; Infinite loop that counts from 0 on up...
				4771	%indvar = phi i32 [ 0, %LoopHeader ], [ %nextindvar, %Loop ]
				4772	%nextindvar = add i32 %indvar, 1
				4773	br label %Loop
				4774	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4775
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4776	</div>
				4777
				4778	<!-- _______________________________________________________________________ -->
				4779	<div class="doc_subsubsection">
				4780	<a name="i_select">'<tt>select</tt>' Instruction</a>
				4781	</div>
				4782
				4783	<div class="doc_text">
				4784
				4785	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4786	<pre>
Dan Gohman	b60ca3c	2008-09-09 01:02:47 +0000	[diff] [blame]	4787	<result> = select <i>selty</i> <cond>, <ty> <val1>, <ty> <val2> <i>; yields ty</i>
				4788
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	4789	<i>selty</i> is either i1 or {<N x i1>}
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4790	</pre>
				4791
				4792	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4793	<p>The '<tt>select</tt>' instruction is used to choose one value based on a
				4794	condition, without branching.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4795
				4796
				4797	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4798	<p>The '<tt>select</tt>' instruction requires an 'i1' value or a vector of 'i1'
				4799	values indicating the condition, and two values of the
				4800	same <a href="#t_firstclass">first class</a> type. If the val1/val2 are
				4801	vectors and the condition is a scalar, then entire vectors are selected, not
				4802	individual elements.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4803
				4804	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4805	<p>If the condition is an i1 and it evaluates to 1, the instruction returns the
				4806	first value argument; otherwise, it returns the second value argument.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4807
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4808	<p>If the condition is a vector of i1, then the value arguments must be vectors
				4809	of the same size, and the selection is done element by element.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4810
				4811	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4812	<pre>
				4813	%X = select i1 true, i8 17, i8 42 <i>; yields i8:17</i>
				4814	</pre>
Dan Gohman	a53eb38	2009-01-22 01:39:38 +0000	[diff] [blame]	4815
				4816	<p>Note that the code generator does not yet support conditions
				4817	with vector type.</p>
				4818
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4819	</div>
				4820
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4821	<!-- _______________________________________________________________________ -->
				4822	<div class="doc_subsubsection">
				4823	<a name="i_call">'<tt>call</tt>' Instruction</a>
				4824	</div>
				4825
				4826	<div class="doc_text">
				4827
				4828	<h5>Syntax:</h5>
				4829	<pre>
Devang Patel	d0bfcc7	2008-10-07 17:48:33 +0000	[diff] [blame]	4830	<result> = [tail] call [<a href="#callingconv">cconv</a>] [<a href="#paramattrs">ret attrs</a>] <ty> [<fnty>*] <fnptrval>(<function args>) [<a href="#fnattrs">fn attrs</a>]
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4831	</pre>
				4832
				4833	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4834	<p>The '<tt>call</tt>' instruction represents a simple function call.</p>
				4835
				4836	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4837	<p>This instruction requires several arguments:</p>
				4838
				4839	<ol>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4840	<li>The optional "tail" marker indicates whether the callee function accesses
				4841	any allocas or varargs in the caller. If the "tail" marker is present,
				4842	the function call is eligible for tail call optimization. Note that calls
				4843	may be marked "tail" even if they do not occur before
				4844	a <a href="#i_ret"><tt>ret</tt></a> instruction.</li>
Devang Patel	ac2fc27	2008-10-06 18:50:38 +0000	[diff] [blame]	4845
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4846	<li>The optional "cconv" marker indicates which <a href="#callingconv">calling
				4847	convention</a> the call should use. If none is specified, the call
				4848	defaults to using C calling conventions.</li>
Devang Patel	ac2fc27	2008-10-06 18:50:38 +0000	[diff] [blame]	4849
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4850	<li>The optional <a href="#paramattrs">Parameter Attributes</a> list for
				4851	return values. Only '<tt>zeroext</tt>', '<tt>signext</tt>', and
				4852	'<tt>inreg</tt>' attributes are valid here.</li>
				4853
				4854	<li>'<tt>ty</tt>': the type of the call instruction itself which is also the
				4855	type of the return value. Functions that return no value are marked
				4856	<tt><a href="#t_void">void</a></tt>.</li>
				4857
				4858	<li>'<tt>fnty</tt>': shall be the signature of the pointer to function value
				4859	being invoked. The argument types must match the types implied by this
				4860	signature. This type can be omitted if the function is not varargs and if
				4861	the function type does not return a pointer to a function.</li>
				4862
				4863	<li>'<tt>fnptrval</tt>': An LLVM value containing a pointer to a function to
				4864	be invoked. In most cases, this is a direct function invocation, but
				4865	indirect <tt>call</tt>s are just as possible, calling an arbitrary pointer
				4866	to function value.</li>
				4867
				4868	<li>'<tt>function args</tt>': argument list whose types match the function
				4869	signature argument types. All arguments must be of
				4870	<a href="#t_firstclass">first class</a> type. If the function signature
				4871	indicates the function accepts a variable number of arguments, the extra
				4872	arguments can be specified.</li>
				4873
				4874	<li>The optional <a href="#fnattrs">function attributes</a> list. Only
				4875	'<tt>noreturn</tt>', '<tt>nounwind</tt>', '<tt>readonly</tt>' and
				4876	'<tt>readnone</tt>' attributes are valid here.</li>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4877	</ol>
				4878
				4879	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4880	<p>The '<tt>call</tt>' instruction is used to cause control flow to transfer to
				4881	a specified function, with its incoming arguments bound to the specified
				4882	values. Upon a '<tt><a href="#i_ret">ret</a></tt>' instruction in the called
				4883	function, control flow continues with the instruction after the function
				4884	call, and the return value of the function is bound to the result
				4885	argument.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4886
				4887	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4888	<pre>
Nick Lewycky	93082fc	2007-09-08 13:57:50 +0000	[diff] [blame]	4889	%retval = call i32 @test(i32 %argc)
Chris Lattner	5e893ef	2008-03-21 17:24:17 +0000	[diff] [blame]	4890	call i32 (i8 , ...) @printf(i8 * %msg, i32 12, i8 42) <i>; yields i32</i>
				4891	%X = tail call i32 @foo() <i>; yields i32</i>
				4892	%Y = tail call <a href="#callingconv">fastcc</a> i32 @foo() <i>; yields i32</i>
				4893	call void %foo(i8 97 signext)
Devang Patel	a3cc537	2008-03-10 20:49:15 +0000	[diff] [blame]	4894
				4895	%struct.A = type { i32, i8 }
Devang Patel	ac2fc27	2008-10-06 18:50:38 +0000	[diff] [blame]	4896	%r = call %struct.A @foo() <i>; yields { 32, i8 }</i>
Dan Gohman	3e70003	2008-10-04 19:00:07 +0000	[diff] [blame]	4897	%gr = extractvalue %struct.A %r, 0 <i>; yields i32</i>
				4898	%gr1 = extractvalue %struct.A %r, 1 <i>; yields i8</i>
Chris Lattner	ac454b3	2008-10-08 06:26:11 +0000	[diff] [blame]	4899	%Z = call void @foo() noreturn <i>; indicates that %foo never returns normally</i>
Matthijs Kooijman	2c4e05a	2008-10-07 10:03:45 +0000	[diff] [blame]	4900	%ZZ = call zeroext i32 @bar() <i>; Return value is %zero extended</i>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4901	</pre>
				4902
				4903	</div>
				4904
				4905	<!-- _______________________________________________________________________ -->
				4906	<div class="doc_subsubsection">
				4907	<a name="i_va_arg">'<tt>va_arg</tt>' Instruction</a>
				4908	</div>
				4909
				4910	<div class="doc_text">
				4911
				4912	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4913	<pre>
				4914	<resultval> = va_arg <va_list*> <arglist>, <argty>
				4915	</pre>
				4916
				4917	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4918	<p>The '<tt>va_arg</tt>' instruction is used to access arguments passed through
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4919	the "variable argument" area of a function call. It is used to implement the
				4920	<tt>va_arg</tt> macro in C.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4921
				4922	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4923	<p>This instruction takes a <tt>va_list*</tt> value and the type of the
				4924	argument. It returns a value of the specified argument type and increments
				4925	the <tt>va_list</tt> to point to the next argument. The actual type
				4926	of <tt>va_list</tt> is target specific.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4927
				4928	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4929	<p>The '<tt>va_arg</tt>' instruction loads an argument of the specified type
				4930	from the specified <tt>va_list</tt> and causes the <tt>va_list</tt> to point
				4931	to the next argument. For more information, see the variable argument
				4932	handling <a href="#int_varargs">Intrinsic Functions</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4933
				4934	<p>It is legal for this instruction to be called in a function which does not
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4935	take a variable number of arguments, for example, the <tt>vfprintf</tt>
				4936	function.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4937
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4938	<p><tt>va_arg</tt> is an LLVM instruction instead of
				4939	an <a href="#intrinsics">intrinsic function</a> because it takes a type as an
				4940	argument.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4941
				4942	<h5>Example:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4943	<p>See the <a href="#int_varargs">variable argument processing</a> section.</p>
				4944
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4945	<p>Note that the code generator does not yet fully support va_arg on many
				4946	targets. Also, it does not currently support va_arg with aggregate types on
				4947	any target.</p>
Dan Gohman	6096719	2009-01-12 23:12:39 +0000	[diff] [blame]	4948
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4949	</div>
				4950
				4951	<!-- *********************************************************************** -->
				4952	<div class="doc_section"> <a name="intrinsics">Intrinsic Functions</a> </div>
				4953	<!-- *********************************************************************** -->
				4954
				4955	<div class="doc_text">
				4956
				4957	<p>LLVM supports the notion of an "intrinsic function". These functions have
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4958	well known names and semantics and are required to follow certain
				4959	restrictions. Overall, these intrinsics represent an extension mechanism for
				4960	the LLVM language that does not require changing all of the transformations
				4961	in LLVM when adding to the language (or the bitcode reader/writer, the
				4962	parser, etc...).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4963
				4964	<p>Intrinsic function names must all start with an "<tt>llvm.</tt>" prefix. This
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4965	prefix is reserved in LLVM for intrinsic names; thus, function names may not
				4966	begin with this prefix. Intrinsic functions must always be external
				4967	functions: you cannot define the body of intrinsic functions. Intrinsic
				4968	functions may only be used in call or invoke instructions: it is illegal to
				4969	take the address of an intrinsic function. Additionally, because intrinsic
				4970	functions are part of the LLVM language, it is required if any are added that
				4971	they be documented here.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4972
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4973	<p>Some intrinsic functions can be overloaded, i.e., the intrinsic represents a
				4974	family of functions that perform the same operation but on different data
				4975	types. Because LLVM can represent over 8 million different integer types,
				4976	overloading is used commonly to allow an intrinsic function to operate on any
				4977	integer type. One or more of the argument types or the result type can be
				4978	overloaded to accept any integer type. Argument types may also be defined as
				4979	exactly matching a previous argument's type or the result type. This allows
				4980	an intrinsic function which accepts multiple arguments, but needs all of them
				4981	to be of the same type, to only be overloaded with respect to a single
				4982	argument or the result.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4983
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4984	<p>Overloaded intrinsics will have the names of its overloaded argument types
				4985	encoded into its function name, each preceded by a period. Only those types
				4986	which are overloaded result in a name suffix. Arguments whose type is matched
				4987	against another type do not. For example, the <tt>llvm.ctpop</tt> function
				4988	can take an integer of any width and returns an integer of exactly the same
				4989	integer width. This leads to a family of functions such as
				4990	<tt>i8 @llvm.ctpop.i8(i8 %val)</tt> and <tt>i29 @llvm.ctpop.i29(i29
				4991	%val)</tt>. Only one type, the return type, is overloaded, and only one type
				4992	suffix is required. Because the argument's type is matched against the return
				4993	type, it does not require its own name suffix.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4994
				4995	<p>To learn how to add an intrinsic function, please see the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	4996	<a href="ExtendingLLVM.html">Extending LLVM Guide</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	4997
				4998	</div>
				4999
				5000	<!-- ======================================================================= -->
				5001	<div class="doc_subsection">
				5002	<a name="int_varargs">Variable Argument Handling Intrinsics</a>
				5003	</div>
				5004
				5005	<div class="doc_text">
				5006
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5007	<p>Variable argument support is defined in LLVM with
				5008	the <a href="#i_va_arg"><tt>va_arg</tt></a> instruction and these three
				5009	intrinsic functions. These functions are related to the similarly named
				5010	macros defined in the <tt><stdarg.h></tt> header file.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5011
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5012	<p>All of these functions operate on arguments that use a target-specific value
				5013	type "<tt>va_list</tt>". The LLVM assembly language reference manual does
				5014	not define what this type is, so all transformations should be prepared to
				5015	handle these functions regardless of the type used.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5016
				5017	<p>This example shows how the <a href="#i_va_arg"><tt>va_arg</tt></a>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5018	instruction and the variable argument handling intrinsic functions are
				5019	used.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5020
				5021	<div class="doc_code">
				5022	<pre>
				5023	define i32 @test(i32 %X, ...) {
				5024	; Initialize variable argument processing
				5025	%ap = alloca i8*
				5026	%ap2 = bitcast i8** %ap to i8*
				5027	call void @llvm.va_start(i8* %ap2)
				5028
				5029	; Read a single integer argument
				5030	%tmp = va_arg i8** %ap, i32
				5031
				5032	; Demonstrate usage of llvm.va_copy and llvm.va_end
				5033	%aq = alloca i8*
				5034	%aq2 = bitcast i8** %aq to i8*
				5035	call void @llvm.va_copy(i8* %aq2, i8* %ap2)
				5036	call void @llvm.va_end(i8* %aq2)
				5037
				5038	; Stop processing of arguments.
				5039	call void @llvm.va_end(i8* %ap2)
				5040	ret i32 %tmp
				5041	}
				5042
				5043	declare void @llvm.va_start(i8*)
				5044	declare void @llvm.va_copy(i8, i8)
				5045	declare void @llvm.va_end(i8*)
				5046	</pre>
				5047	</div>
				5048
				5049	</div>
				5050
				5051	<!-- _______________________________________________________________________ -->
				5052	<div class="doc_subsubsection">
				5053	<a name="int_va_start">'<tt>llvm.va_start</tt>' Intrinsic</a>
				5054	</div>
				5055
				5056
				5057	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5058
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5059	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5060	<pre>
				5061	declare void %llvm.va_start(i8* <arglist>)
				5062	</pre>
				5063
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5064	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5065	<p>The '<tt>llvm.va_start</tt>' intrinsic initializes <tt>*<arglist></tt>
				5066	for subsequent use by <tt><a href="#i_va_arg">va_arg</a></tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5067
				5068	<h5>Arguments:</h5>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	5069	<p>The argument is a pointer to a <tt>va_list</tt> element to initialize.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5070
				5071	<h5>Semantics:</h5>
Dan Gohman	2672f3e	2008-10-14 16:51:45 +0000	[diff] [blame]	5072	<p>The '<tt>llvm.va_start</tt>' intrinsic works just like the <tt>va_start</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5073	macro available in C. In a target-dependent way, it initializes
				5074	the <tt>va_list</tt> element to which the argument points, so that the next
				5075	call to <tt>va_arg</tt> will produce the first variable argument passed to
				5076	the function. Unlike the C <tt>va_start</tt> macro, this intrinsic does not
				5077	need to know the last argument of the function as the compiler can figure
				5078	that out.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5079
				5080	</div>
				5081
				5082	<!-- _______________________________________________________________________ -->
				5083	<div class="doc_subsubsection">
				5084	<a name="int_va_end">'<tt>llvm.va_end</tt>' Intrinsic</a>
				5085	</div>
				5086
				5087	<div class="doc_text">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5088
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5089	<h5>Syntax:</h5>
				5090	<pre>
				5091	declare void @llvm.va_end(i8* <arglist>)
				5092	</pre>
				5093
				5094	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5095	<p>The '<tt>llvm.va_end</tt>' intrinsic destroys <tt>*<arglist></tt>,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5096	which has been initialized previously
				5097	with <tt><a href="#int_va_start">llvm.va_start</a></tt>
				5098	or <tt><a href="#i_va_copy">llvm.va_copy</a></tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5099
				5100	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5101	<p>The argument is a pointer to a <tt>va_list</tt> to destroy.</p>
				5102
				5103	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5104	<p>The '<tt>llvm.va_end</tt>' intrinsic works just like the <tt>va_end</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5105	macro available in C. In a target-dependent way, it destroys
				5106	the <tt>va_list</tt> element to which the argument points. Calls
				5107	to <a href="#int_va_start"><tt>llvm.va_start</tt></a>
				5108	and <a href="#int_va_copy"> <tt>llvm.va_copy</tt></a> must be matched exactly
				5109	with calls to <tt>llvm.va_end</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5110
				5111	</div>
				5112
				5113	<!-- _______________________________________________________________________ -->
				5114	<div class="doc_subsubsection">
				5115	<a name="int_va_copy">'<tt>llvm.va_copy</tt>' Intrinsic</a>
				5116	</div>
				5117
				5118	<div class="doc_text">
				5119
				5120	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5121	<pre>
				5122	declare void @llvm.va_copy(i8* <destarglist>, i8* <srcarglist>)
				5123	</pre>
				5124
				5125	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5126	<p>The '<tt>llvm.va_copy</tt>' intrinsic copies the current argument position
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5127	from the source argument list to the destination argument list.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5128
				5129	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5130	<p>The first argument is a pointer to a <tt>va_list</tt> element to initialize.
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5131	The second argument is a pointer to a <tt>va_list</tt> element to copy
				5132	from.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5133
				5134	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5135	<p>The '<tt>llvm.va_copy</tt>' intrinsic works just like the <tt>va_copy</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5136	macro available in C. In a target-dependent way, it copies the
				5137	source <tt>va_list</tt> element into the destination <tt>va_list</tt>
				5138	element. This intrinsic is necessary because
				5139	the <tt><a href="#int_va_start"> llvm.va_start</a></tt> intrinsic may be
				5140	arbitrarily complex and require, for example, memory allocation.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5141
				5142	</div>
				5143
				5144	<!-- ======================================================================= -->
				5145	<div class="doc_subsection">
				5146	<a name="int_gc">Accurate Garbage Collection Intrinsics</a>
				5147	</div>
				5148
				5149	<div class="doc_text">
				5150
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5151	<p>LLVM support for <a href="GarbageCollection.html">Accurate Garbage
Chris Lattner	9645148	2008-08-05 18:29:16 +0000	[diff] [blame]	5152	Collection</a> (GC) requires the implementation and generation of these
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5153	intrinsics. These intrinsics allow identification of <a href="#int_gcroot">GC
				5154	roots on the stack</a>, as well as garbage collector implementations that
				5155	require <a href="#int_gcread">read</a> and <a href="#int_gcwrite">write</a>
				5156	barriers. Front-ends for type-safe garbage collected languages should generate
				5157	these intrinsics to make use of the LLVM garbage collectors. For more details,
				5158	see <a href="GarbageCollection.html">Accurate Garbage Collection with
				5159	LLVM</a>.</p>
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	5160
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5161	<p>The garbage collection intrinsics only operate on objects in the generic
				5162	address space (address space zero).</p>
Christopher Lamb	cfe0096	2007-12-17 01:00:21 +0000	[diff] [blame]	5163
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5164	</div>
				5165
				5166	<!-- _______________________________________________________________________ -->
				5167	<div class="doc_subsubsection">
				5168	<a name="int_gcroot">'<tt>llvm.gcroot</tt>' Intrinsic</a>
				5169	</div>
				5170
				5171	<div class="doc_text">
				5172
				5173	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5174	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5175	declare void @llvm.gcroot(i8** %ptrloc, i8* %metadata)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5176	</pre>
				5177
				5178	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5179	<p>The '<tt>llvm.gcroot</tt>' intrinsic declares the existence of a GC root to
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5180	the code generator, and allows some metadata to be associated with it.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5181
				5182	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5183	<p>The first argument specifies the address of a stack object that contains the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5184	root pointer. The second pointer (which must be either a constant or a
				5185	global value address) contains the meta-data to be associated with the
				5186	root.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5187
				5188	<h5>Semantics:</h5>
Chris Lattner	a7d94ba	2008-04-24 05:59:56 +0000	[diff] [blame]	5189	<p>At runtime, a call to this intrinsic stores a null pointer into the "ptrloc"
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5190	location. At compile-time, the code generator generates information to allow
				5191	the runtime to find the pointer at GC safe points. The '<tt>llvm.gcroot</tt>'
				5192	intrinsic may only be used in a function which <a href="#gc">specifies a GC
				5193	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5194
				5195	</div>
				5196
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5197	<!-- _______________________________________________________________________ -->
				5198	<div class="doc_subsubsection">
				5199	<a name="int_gcread">'<tt>llvm.gcread</tt>' Intrinsic</a>
				5200	</div>
				5201
				5202	<div class="doc_text">
				5203
				5204	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5205	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5206	declare i8* @llvm.gcread(i8* %ObjPtr, i8** %Ptr)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5207	</pre>
				5208
				5209	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5210	<p>The '<tt>llvm.gcread</tt>' intrinsic identifies reads of references from heap
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5211	locations, allowing garbage collector implementations that require read
				5212	barriers.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5213
				5214	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5215	<p>The second argument is the address to read from, which should be an address
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5216	allocated from the garbage collector. The first object is a pointer to the
				5217	start of the referenced object, if needed by the language runtime (otherwise
				5218	null).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5219
				5220	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5221	<p>The '<tt>llvm.gcread</tt>' intrinsic has the same semantics as a load
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5222	instruction, but may be replaced with substantially more complex code by the
				5223	garbage collector runtime, as needed. The '<tt>llvm.gcread</tt>' intrinsic
				5224	may only be used in a function which <a href="#gc">specifies a GC
				5225	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5226
				5227	</div>
				5228
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5229	<!-- _______________________________________________________________________ -->
				5230	<div class="doc_subsubsection">
				5231	<a name="int_gcwrite">'<tt>llvm.gcwrite</tt>' Intrinsic</a>
				5232	</div>
				5233
				5234	<div class="doc_text">
				5235
				5236	<h5>Syntax:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5237	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5238	declare void @llvm.gcwrite(i8* %P1, i8* %Obj, i8** %P2)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5239	</pre>
				5240
				5241	<h5>Overview:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5242	<p>The '<tt>llvm.gcwrite</tt>' intrinsic identifies writes of references to heap
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5243	locations, allowing garbage collector implementations that require write
				5244	barriers (such as generational or reference counting collectors).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5245
				5246	<h5>Arguments:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5247	<p>The first argument is the reference to store, the second is the start of the
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5248	object to store it to, and the third is the address of the field of Obj to
				5249	store to. If the runtime does not require a pointer to the object, Obj may
				5250	be null.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5251
				5252	<h5>Semantics:</h5>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5253	<p>The '<tt>llvm.gcwrite</tt>' intrinsic has the same semantics as a store
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5254	instruction, but may be replaced with substantially more complex code by the
				5255	garbage collector runtime, as needed. The '<tt>llvm.gcwrite</tt>' intrinsic
				5256	may only be used in a function which <a href="#gc">specifies a GC
				5257	algorithm</a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5258
				5259	</div>
				5260
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5261	<!-- ======================================================================= -->
				5262	<div class="doc_subsection">
				5263	<a name="int_codegen">Code Generator Intrinsics</a>
				5264	</div>
				5265
				5266	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5267
				5268	<p>These intrinsics are provided by LLVM to expose special features that may
				5269	only be implemented with code generator support.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5270
				5271	</div>
				5272
				5273	<!-- _______________________________________________________________________ -->
				5274	<div class="doc_subsubsection">
				5275	<a name="int_returnaddress">'<tt>llvm.returnaddress</tt>' Intrinsic</a>
				5276	</div>
				5277
				5278	<div class="doc_text">
				5279
				5280	<h5>Syntax:</h5>
				5281	<pre>
				5282	declare i8 *@llvm.returnaddress(i32 <level>)
				5283	</pre>
				5284
				5285	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5286	<p>The '<tt>llvm.returnaddress</tt>' intrinsic attempts to compute a
				5287	target-specific value indicating the return address of the current function
				5288	or one of its callers.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5289
				5290	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5291	<p>The argument to this intrinsic indicates which function to return the address
				5292	for. Zero indicates the calling function, one indicates its caller, etc.
				5293	The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5294
				5295	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5296	<p>The '<tt>llvm.returnaddress</tt>' intrinsic either returns a pointer
				5297	indicating the return address of the specified call frame, or zero if it
				5298	cannot be identified. The value returned by this intrinsic is likely to be
				5299	incorrect or 0 for arguments other than zero, so it should only be used for
				5300	debugging purposes.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5301
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5302	<p>Note that calling this intrinsic does not prevent function inlining or other
				5303	aggressive transformations, so the value returned may not be that of the
				5304	obvious source-language caller.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5305
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5306	</div>
				5307
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5308	<!-- _______________________________________________________________________ -->
				5309	<div class="doc_subsubsection">
				5310	<a name="int_frameaddress">'<tt>llvm.frameaddress</tt>' Intrinsic</a>
				5311	</div>
				5312
				5313	<div class="doc_text">
				5314
				5315	<h5>Syntax:</h5>
				5316	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5317	declare i8 *@llvm.frameaddress(i32 <level>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5318	</pre>
				5319
				5320	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5321	<p>The '<tt>llvm.frameaddress</tt>' intrinsic attempts to return the
				5322	target-specific frame pointer value for the specified stack frame.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5323
				5324	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5325	<p>The argument to this intrinsic indicates which function to return the frame
				5326	pointer for. Zero indicates the calling function, one indicates its caller,
				5327	etc. The argument is <b>required</b> to be a constant integer value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5328
				5329	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5330	<p>The '<tt>llvm.frameaddress</tt>' intrinsic either returns a pointer
				5331	indicating the frame address of the specified call frame, or zero if it
				5332	cannot be identified. The value returned by this intrinsic is likely to be
				5333	incorrect or 0 for arguments other than zero, so it should only be used for
				5334	debugging purposes.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5335
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5336	<p>Note that calling this intrinsic does not prevent function inlining or other
				5337	aggressive transformations, so the value returned may not be that of the
				5338	obvious source-language caller.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5339
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5340	</div>
				5341
				5342	<!-- _______________________________________________________________________ -->
				5343	<div class="doc_subsubsection">
				5344	<a name="int_stacksave">'<tt>llvm.stacksave</tt>' Intrinsic</a>
				5345	</div>
				5346
				5347	<div class="doc_text">
				5348
				5349	<h5>Syntax:</h5>
				5350	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5351	declare i8 *@llvm.stacksave()
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5352	</pre>
				5353
				5354	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5355	<p>The '<tt>llvm.stacksave</tt>' intrinsic is used to remember the current state
				5356	of the function stack, for use
				5357	with <a href="#int_stackrestore"> <tt>llvm.stackrestore</tt></a>. This is
				5358	useful for implementing language features like scoped automatic variable
				5359	sized arrays in C99.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5360
				5361	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5362	<p>This intrinsic returns a opaque pointer value that can be passed
				5363	to <a href="#int_stackrestore"><tt>llvm.stackrestore</tt></a>. When
				5364	an <tt>llvm.stackrestore</tt> intrinsic is executed with a value saved
				5365	from <tt>llvm.stacksave</tt>, it effectively restores the state of the stack
				5366	to the state it was in when the <tt>llvm.stacksave</tt> intrinsic executed.
				5367	In practice, this pops any <a href="#i_alloca">alloca</a> blocks from the
				5368	stack that were allocated after the <tt>llvm.stacksave</tt> was executed.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5369
				5370	</div>
				5371
				5372	<!-- _______________________________________________________________________ -->
				5373	<div class="doc_subsubsection">
				5374	<a name="int_stackrestore">'<tt>llvm.stackrestore</tt>' Intrinsic</a>
				5375	</div>
				5376
				5377	<div class="doc_text">
				5378
				5379	<h5>Syntax:</h5>
				5380	<pre>
				5381	declare void @llvm.stackrestore(i8 * %ptr)
				5382	</pre>
				5383
				5384	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5385	<p>The '<tt>llvm.stackrestore</tt>' intrinsic is used to restore the state of
				5386	the function stack to the state it was in when the
				5387	corresponding <a href="#int_stacksave"><tt>llvm.stacksave</tt></a> intrinsic
				5388	executed. This is useful for implementing language features like scoped
				5389	automatic variable sized arrays in C99.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5390
				5391	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5392	<p>See the description
				5393	for <a href="#int_stacksave"><tt>llvm.stacksave</tt></a>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5394
				5395	</div>
				5396
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5397	<!-- _______________________________________________________________________ -->
				5398	<div class="doc_subsubsection">
				5399	<a name="int_prefetch">'<tt>llvm.prefetch</tt>' Intrinsic</a>
				5400	</div>
				5401
				5402	<div class="doc_text">
				5403
				5404	<h5>Syntax:</h5>
				5405	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5406	declare void @llvm.prefetch(i8* <address>, i32 <rw>, i32 <locality>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5407	</pre>
				5408
				5409	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5410	<p>The '<tt>llvm.prefetch</tt>' intrinsic is a hint to the code generator to
				5411	insert a prefetch instruction if supported; otherwise, it is a noop.
				5412	Prefetches have no effect on the behavior of the program but can change its
				5413	performance characteristics.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5414
				5415	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5416	<p><tt>address</tt> is the address to be prefetched, <tt>rw</tt> is the
				5417	specifier determining if the fetch should be for a read (0) or write (1),
				5418	and <tt>locality</tt> is a temporal locality specifier ranging from (0) - no
				5419	locality, to (3) - extremely local keep in cache. The <tt>rw</tt>
				5420	and <tt>locality</tt> arguments must be constant integers.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5421
				5422	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5423	<p>This intrinsic does not modify the behavior of the program. In particular,
				5424	prefetches cannot trap and do not produce a value. On targets that support
				5425	this intrinsic, the prefetch can provide hints to the processor cache for
				5426	better performance.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5427
				5428	</div>
				5429
				5430	<!-- _______________________________________________________________________ -->
				5431	<div class="doc_subsubsection">
				5432	<a name="int_pcmarker">'<tt>llvm.pcmarker</tt>' Intrinsic</a>
				5433	</div>
				5434
				5435	<div class="doc_text">
				5436
				5437	<h5>Syntax:</h5>
				5438	<pre>
Chris Lattner	38bd5dd	2007-09-21 17:30:40 +0000	[diff] [blame]	5439	declare void @llvm.pcmarker(i32 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5440	</pre>
				5441
				5442	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5443	<p>The '<tt>llvm.pcmarker</tt>' intrinsic is a method to export a Program
				5444	Counter (PC) in a region of code to simulators and other tools. The method
				5445	is target specific, but it is expected that the marker will use exported
				5446	symbols to transmit the PC of the marker. The marker makes no guarantees
				5447	that it will remain with any specific instruction after optimizations. It is
				5448	possible that the presence of a marker will inhibit optimizations. The
				5449	intended use is to be inserted after optimizations to allow correlations of
				5450	simulation runs.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5451
				5452	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5453	<p><tt>id</tt> is a numerical id identifying the marker.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5454
				5455	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5456	<p>This intrinsic does not modify the behavior of the program. Backends that do
				5457	not support this intrinisic may ignore it.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5458
				5459	</div>
				5460
				5461	<!-- _______________________________________________________________________ -->
				5462	<div class="doc_subsubsection">
				5463	<a name="int_readcyclecounter">'<tt>llvm.readcyclecounter</tt>' Intrinsic</a>
				5464	</div>
				5465
				5466	<div class="doc_text">
				5467
				5468	<h5>Syntax:</h5>
				5469	<pre>
				5470	declare i64 @llvm.readcyclecounter( )
				5471	</pre>
				5472
				5473	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5474	<p>The '<tt>llvm.readcyclecounter</tt>' intrinsic provides access to the cycle
				5475	counter register (or similar low latency, high accuracy clocks) on those
				5476	targets that support it. On X86, it should map to RDTSC. On Alpha, it
				5477	should map to RPCC. As the backing counters overflow quickly (on the order
				5478	of 9 seconds on alpha), this should only be used for small timings.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5479
				5480	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5481	<p>When directly supported, reading the cycle counter should not modify any
				5482	memory. Implementations are allowed to either return a application specific
				5483	value or a system wide value. On backends without support, this is lowered
				5484	to a constant 0.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5485
				5486	</div>
				5487
				5488	<!-- ======================================================================= -->
				5489	<div class="doc_subsection">
				5490	<a name="int_libc">Standard C Library Intrinsics</a>
				5491	</div>
				5492
				5493	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5494
				5495	<p>LLVM provides intrinsics for a few important standard C library functions.
				5496	These intrinsics allow source-language front-ends to pass information about
				5497	the alignment of the pointer arguments to the code generator, providing
				5498	opportunity for more efficient code generation.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5499
				5500	</div>
				5501
				5502	<!-- _______________________________________________________________________ -->
				5503	<div class="doc_subsubsection">
				5504	<a name="int_memcpy">'<tt>llvm.memcpy</tt>' Intrinsic</a>
				5505	</div>
				5506
				5507	<div class="doc_text">
				5508
				5509	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5510	<p>This is an overloaded intrinsic. You can use <tt>llvm.memcpy</tt> on any
				5511	integer bit width. Not all targets support all bit widths however.</p>
				5512
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5513	<pre>
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5514	declare void @llvm.memcpy.i8(i8 * <dest>, i8 * <src>,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5515	i8 <len>, i32 <align>)
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5516	declare void @llvm.memcpy.i16(i8 * <dest>, i8 * <src>,
				5517	i16 <len>, i32 <align>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5518	declare void @llvm.memcpy.i32(i8 * <dest>, i8 * <src>,
				5519	i32 <len>, i32 <align>)
				5520	declare void @llvm.memcpy.i64(i8 * <dest>, i8 * <src>,
				5521	i64 <len>, i32 <align>)
				5522	</pre>
				5523
				5524	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5525	<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
				5526	source location to the destination location.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5527
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5528	<p>Note that, unlike the standard libc function, the <tt>llvm.memcpy.*</tt>
				5529	intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5530
				5531	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5532	<p>The first argument is a pointer to the destination, the second is a pointer
				5533	to the source. The third argument is an integer argument specifying the
				5534	number of bytes to copy, and the fourth argument is the alignment of the
				5535	source and destination locations.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5536
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5537	<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
				5538	then the caller guarantees that both the source and destination pointers are
				5539	aligned to that boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5540
				5541	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5542	<p>The '<tt>llvm.memcpy.*</tt>' intrinsics copy a block of memory from the
				5543	source location to the destination location, which are not allowed to
				5544	overlap. It copies "len" bytes of memory over. If the argument is known to
				5545	be aligned to some boundary, this can be specified as the fourth argument,
				5546	otherwise it should be set to 0 or 1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5547
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5548	</div>
				5549
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5550	<!-- _______________________________________________________________________ -->
				5551	<div class="doc_subsubsection">
				5552	<a name="int_memmove">'<tt>llvm.memmove</tt>' Intrinsic</a>
				5553	</div>
				5554
				5555	<div class="doc_text">
				5556
				5557	<h5>Syntax:</h5>
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5558	<p>This is an overloaded intrinsic. You can use llvm.memmove on any integer bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5559	width. Not all targets support all bit widths however.</p>
				5560
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5561	<pre>
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5562	declare void @llvm.memmove.i8(i8 * <dest>, i8 * <src>,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5563	i8 <len>, i32 <align>)
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5564	declare void @llvm.memmove.i16(i8 * <dest>, i8 * <src>,
				5565	i16 <len>, i32 <align>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5566	declare void @llvm.memmove.i32(i8 * <dest>, i8 * <src>,
				5567	i32 <len>, i32 <align>)
				5568	declare void @llvm.memmove.i64(i8 * <dest>, i8 * <src>,
				5569	i64 <len>, i32 <align>)
				5570	</pre>
				5571
				5572	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5573	<p>The '<tt>llvm.memmove.*</tt>' intrinsics move a block of memory from the
				5574	source location to the destination location. It is similar to the
				5575	'<tt>llvm.memcpy</tt>' intrinsic but allows the two memory locations to
				5576	overlap.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5577
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5578	<p>Note that, unlike the standard libc function, the <tt>llvm.memmove.*</tt>
				5579	intrinsics do not return a value, and takes an extra alignment argument.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5580
				5581	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5582	<p>The first argument is a pointer to the destination, the second is a pointer
				5583	to the source. The third argument is an integer argument specifying the
				5584	number of bytes to copy, and the fourth argument is the alignment of the
				5585	source and destination locations.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5586
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5587	<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
				5588	then the caller guarantees that the source and destination pointers are
				5589	aligned to that boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5590
				5591	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5592	<p>The '<tt>llvm.memmove.*</tt>' intrinsics copy a block of memory from the
				5593	source location to the destination location, which may overlap. It copies
				5594	"len" bytes of memory over. If the argument is known to be aligned to some
				5595	boundary, this can be specified as the fourth argument, otherwise it should
				5596	be set to 0 or 1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5597
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5598	</div>
				5599
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5600	<!-- _______________________________________________________________________ -->
				5601	<div class="doc_subsubsection">
				5602	<a name="int_memset">'<tt>llvm.memset.*</tt>' Intrinsics</a>
				5603	</div>
				5604
				5605	<div class="doc_text">
				5606
				5607	<h5>Syntax:</h5>
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5608	<p>This is an overloaded intrinsic. You can use llvm.memset on any integer bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5609	width. Not all targets support all bit widths however.</p>
				5610
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5611	<pre>
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5612	declare void @llvm.memset.i8(i8 * <dest>, i8 <val>,
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5613	i8 <len>, i32 <align>)
Chris Lattner	82c2e43	2008-11-21 16:42:48 +0000	[diff] [blame]	5614	declare void @llvm.memset.i16(i8 * <dest>, i8 <val>,
				5615	i16 <len>, i32 <align>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5616	declare void @llvm.memset.i32(i8 * <dest>, i8 <val>,
				5617	i32 <len>, i32 <align>)
				5618	declare void @llvm.memset.i64(i8 * <dest>, i8 <val>,
				5619	i64 <len>, i32 <align>)
				5620	</pre>
				5621
				5622	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5623	<p>The '<tt>llvm.memset.*</tt>' intrinsics fill a block of memory with a
				5624	particular byte value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5625
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5626	<p>Note that, unlike the standard libc function, the <tt>llvm.memset</tt>
				5627	intrinsic does not return a value, and takes an extra alignment argument.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5628
				5629	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5630	<p>The first argument is a pointer to the destination to fill, the second is the
				5631	byte value to fill it with, the third argument is an integer argument
				5632	specifying the number of bytes to fill, and the fourth argument is the known
				5633	alignment of destination location.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5634
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5635	<p>If the call to this intrinisic has an alignment value that is not 0 or 1,
				5636	then the caller guarantees that the destination pointer is aligned to that
				5637	boundary.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5638
				5639	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5640	<p>The '<tt>llvm.memset.*</tt>' intrinsics fill "len" bytes of memory starting
				5641	at the destination location. If the argument is known to be aligned to some
				5642	boundary, this can be specified as the fourth argument, otherwise it should
				5643	be set to 0 or 1.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5644
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5645	</div>
				5646
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5647	<!-- _______________________________________________________________________ -->
				5648	<div class="doc_subsubsection">
				5649	<a name="int_sqrt">'<tt>llvm.sqrt.*</tt>' Intrinsic</a>
				5650	</div>
				5651
				5652	<div class="doc_text">
				5653
				5654	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5655	<p>This is an overloaded intrinsic. You can use <tt>llvm.sqrt</tt> on any
				5656	floating point or vector of floating point type. Not all targets support all
				5657	types however.</p>
				5658
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5659	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5660	declare float @llvm.sqrt.f32(float %Val)
				5661	declare double @llvm.sqrt.f64(double %Val)
				5662	declare x86_fp80 @llvm.sqrt.f80(x86_fp80 %Val)
				5663	declare fp128 @llvm.sqrt.f128(fp128 %Val)
				5664	declare ppc_fp128 @llvm.sqrt.ppcf128(ppc_fp128 %Val)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5665	</pre>
				5666
				5667	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5668	<p>The '<tt>llvm.sqrt</tt>' intrinsics return the sqrt of the specified operand,
				5669	returning the same value as the libm '<tt>sqrt</tt>' functions would.
				5670	Unlike <tt>sqrt</tt> in libm, however, <tt>llvm.sqrt</tt> has undefined
				5671	behavior for negative numbers other than -0.0 (which allows for better
				5672	optimization, because there is no need to worry about errno being
				5673	set). <tt>llvm.sqrt(-0.0)</tt> is defined to return -0.0 like IEEE sqrt.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5674
				5675	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5676	<p>The argument and return value are floating point numbers of the same
				5677	type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5678
				5679	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5680	<p>This function returns the sqrt of the specified operand if it is a
				5681	nonnegative floating point number.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5682
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5683	</div>
				5684
				5685	<!-- _______________________________________________________________________ -->
				5686	<div class="doc_subsubsection">
				5687	<a name="int_powi">'<tt>llvm.powi.*</tt>' Intrinsic</a>
				5688	</div>
				5689
				5690	<div class="doc_text">
				5691
				5692	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5693	<p>This is an overloaded intrinsic. You can use <tt>llvm.powi</tt> on any
				5694	floating point or vector of floating point type. Not all targets support all
				5695	types however.</p>
				5696
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5697	<pre>
Dale Johannesen	f9adbb6	2007-10-02 17:47:38 +0000	[diff] [blame]	5698	declare float @llvm.powi.f32(float %Val, i32 %power)
				5699	declare double @llvm.powi.f64(double %Val, i32 %power)
				5700	declare x86_fp80 @llvm.powi.f80(x86_fp80 %Val, i32 %power)
				5701	declare fp128 @llvm.powi.f128(fp128 %Val, i32 %power)
				5702	declare ppc_fp128 @llvm.powi.ppcf128(ppc_fp128 %Val, i32 %power)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5703	</pre>
				5704
				5705	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5706	<p>The '<tt>llvm.powi.*</tt>' intrinsics return the first operand raised to the
				5707	specified (positive or negative) power. The order of evaluation of
				5708	multiplications is not defined. When a vector of floating point type is
				5709	used, the second argument remains a scalar integer value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5710
				5711	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5712	<p>The second argument is an integer power, and the first is a value to raise to
				5713	that power.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5714
				5715	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5716	<p>This function returns the first value raised to the second power with an
				5717	unspecified sequence of rounding operations.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5718
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5719	</div>
				5720
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5721	<!-- _______________________________________________________________________ -->
				5722	<div class="doc_subsubsection">
				5723	<a name="int_sin">'<tt>llvm.sin.*</tt>' Intrinsic</a>
				5724	</div>
				5725
				5726	<div class="doc_text">
				5727
				5728	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5729	<p>This is an overloaded intrinsic. You can use <tt>llvm.sin</tt> on any
				5730	floating point or vector of floating point type. Not all targets support all
				5731	types however.</p>
				5732
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5733	<pre>
				5734	declare float @llvm.sin.f32(float %Val)
				5735	declare double @llvm.sin.f64(double %Val)
				5736	declare x86_fp80 @llvm.sin.f80(x86_fp80 %Val)
				5737	declare fp128 @llvm.sin.f128(fp128 %Val)
				5738	declare ppc_fp128 @llvm.sin.ppcf128(ppc_fp128 %Val)
				5739	</pre>
				5740
				5741	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5742	<p>The '<tt>llvm.sin.*</tt>' intrinsics return the sine of the operand.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5743
				5744	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5745	<p>The argument and return value are floating point numbers of the same
				5746	type.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5747
				5748	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5749	<p>This function returns the sine of the specified operand, returning the same
				5750	values as the libm <tt>sin</tt> functions would, and handles error conditions
				5751	in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5752
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5753	</div>
				5754
				5755	<!-- _______________________________________________________________________ -->
				5756	<div class="doc_subsubsection">
				5757	<a name="int_cos">'<tt>llvm.cos.*</tt>' Intrinsic</a>
				5758	</div>
				5759
				5760	<div class="doc_text">
				5761
				5762	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5763	<p>This is an overloaded intrinsic. You can use <tt>llvm.cos</tt> on any
				5764	floating point or vector of floating point type. Not all targets support all
				5765	types however.</p>
				5766
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5767	<pre>
				5768	declare float @llvm.cos.f32(float %Val)
				5769	declare double @llvm.cos.f64(double %Val)
				5770	declare x86_fp80 @llvm.cos.f80(x86_fp80 %Val)
				5771	declare fp128 @llvm.cos.f128(fp128 %Val)
				5772	declare ppc_fp128 @llvm.cos.ppcf128(ppc_fp128 %Val)
				5773	</pre>
				5774
				5775	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5776	<p>The '<tt>llvm.cos.*</tt>' intrinsics return the cosine of the operand.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5777
				5778	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5779	<p>The argument and return value are floating point numbers of the same
				5780	type.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5781
				5782	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5783	<p>This function returns the cosine of the specified operand, returning the same
				5784	values as the libm <tt>cos</tt> functions would, and handles error conditions
				5785	in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5786
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5787	</div>
				5788
				5789	<!-- _______________________________________________________________________ -->
				5790	<div class="doc_subsubsection">
				5791	<a name="int_pow">'<tt>llvm.pow.*</tt>' Intrinsic</a>
				5792	</div>
				5793
				5794	<div class="doc_text">
				5795
				5796	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5797	<p>This is an overloaded intrinsic. You can use <tt>llvm.pow</tt> on any
				5798	floating point or vector of floating point type. Not all targets support all
				5799	types however.</p>
				5800
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5801	<pre>
				5802	declare float @llvm.pow.f32(float %Val, float %Power)
				5803	declare double @llvm.pow.f64(double %Val, double %Power)
				5804	declare x86_fp80 @llvm.pow.f80(x86_fp80 %Val, x86_fp80 %Power)
				5805	declare fp128 @llvm.pow.f128(fp128 %Val, fp128 %Power)
				5806	declare ppc_fp128 @llvm.pow.ppcf128(ppc_fp128 %Val, ppc_fp128 Power)
				5807	</pre>
				5808
				5809	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5810	<p>The '<tt>llvm.pow.*</tt>' intrinsics return the first operand raised to the
				5811	specified (positive or negative) power.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5812
				5813	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5814	<p>The second argument is a floating point power, and the first is a value to
				5815	raise to that power.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5816
				5817	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5818	<p>This function returns the first value raised to the second power, returning
				5819	the same values as the libm <tt>pow</tt> functions would, and handles error
				5820	conditions in the same way.</p>
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5821
Dan Gohman	361079c	2007-10-15 20:30:11 +0000	[diff] [blame]	5822	</div>
				5823
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5824	<!-- ======================================================================= -->
				5825	<div class="doc_subsection">
				5826	<a name="int_manip">Bit Manipulation Intrinsics</a>
				5827	</div>
				5828
				5829	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5830
				5831	<p>LLVM provides intrinsics for a few important bit manipulation operations.
				5832	These allow efficient code generation for some algorithms.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5833
				5834	</div>
				5835
				5836	<!-- _______________________________________________________________________ -->
				5837	<div class="doc_subsubsection">
				5838	<a name="int_bswap">'<tt>llvm.bswap.*</tt>' Intrinsics</a>
				5839	</div>
				5840
				5841	<div class="doc_text">
				5842
				5843	<h5>Syntax:</h5>
				5844	<p>This is an overloaded intrinsic function. You can use bswap on any integer
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5845	type that is an even number of bytes (i.e. BitWidth % 16 == 0).</p>
				5846
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5847	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5848	declare i16 @llvm.bswap.i16(i16 <id>)
				5849	declare i32 @llvm.bswap.i32(i32 <id>)
				5850	declare i64 @llvm.bswap.i64(i64 <id>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5851	</pre>
				5852
				5853	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5854	<p>The '<tt>llvm.bswap</tt>' family of intrinsics is used to byte swap integer
				5855	values with an even number of bytes (positive multiple of 16 bits). These
				5856	are useful for performing operations on data that is not in the target's
				5857	native byte order.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5858
				5859	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5860	<p>The <tt>llvm.bswap.i16</tt> intrinsic returns an i16 value that has the high
				5861	and low byte of the input i16 swapped. Similarly,
				5862	the <tt>llvm.bswap.i32</tt> intrinsic returns an i32 value that has the four
				5863	bytes of the input i32 swapped, so that if the input bytes are numbered 0, 1,
				5864	2, 3 then the returned i32 will have its bytes in 3, 2, 1, 0 order.
				5865	The <tt>llvm.bswap.i48</tt>, <tt>llvm.bswap.i64</tt> and other intrinsics
				5866	extend this concept to additional even-byte lengths (6 bytes, 8 bytes and
				5867	more, respectively).</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5868
				5869	</div>
				5870
				5871	<!-- _______________________________________________________________________ -->
				5872	<div class="doc_subsubsection">
				5873	<a name="int_ctpop">'<tt>llvm.ctpop.*</tt>' Intrinsic</a>
				5874	</div>
				5875
				5876	<div class="doc_text">
				5877
				5878	<h5>Syntax:</h5>
				5879	<p>This is an overloaded intrinsic. You can use llvm.ctpop on any integer bit
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5880	width. Not all targets support all bit widths however.</p>
				5881
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5882	<pre>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	5883	declare i8 @llvm.ctpop.i8(i8 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5884	declare i16 @llvm.ctpop.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5885	declare i32 @llvm.ctpop.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5886	declare i64 @llvm.ctpop.i64(i64 <src>)
				5887	declare i256 @llvm.ctpop.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5888	</pre>
				5889
				5890	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5891	<p>The '<tt>llvm.ctpop</tt>' family of intrinsics counts the number of bits set
				5892	in a value.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5893
				5894	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5895	<p>The only argument is the value to be counted. The argument may be of any
				5896	integer type. The return type must match the argument type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5897
				5898	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5899	<p>The '<tt>llvm.ctpop</tt>' intrinsic counts the 1's in a variable.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5900
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5901	</div>
				5902
				5903	<!-- _______________________________________________________________________ -->
				5904	<div class="doc_subsubsection">
				5905	<a name="int_ctlz">'<tt>llvm.ctlz.*</tt>' Intrinsic</a>
				5906	</div>
				5907
				5908	<div class="doc_text">
				5909
				5910	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5911	<p>This is an overloaded intrinsic. You can use <tt>llvm.ctlz</tt> on any
				5912	integer bit width. Not all targets support all bit widths however.</p>
				5913
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5914	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5915	declare i8 @llvm.ctlz.i8 (i8 <src>)
				5916	declare i16 @llvm.ctlz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5917	declare i32 @llvm.ctlz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5918	declare i64 @llvm.ctlz.i64(i64 <src>)
				5919	declare i256 @llvm.ctlz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5920	</pre>
				5921
				5922	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5923	<p>The '<tt>llvm.ctlz</tt>' family of intrinsic functions counts the number of
				5924	leading zeros in a variable.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5925
				5926	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5927	<p>The only argument is the value to be counted. The argument may be of any
				5928	integer type. The return type must match the argument type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5929
				5930	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5931	<p>The '<tt>llvm.ctlz</tt>' intrinsic counts the leading (most significant)
				5932	zeros in a variable. If the src == 0 then the result is the size in bits of
				5933	the type of src. For example, <tt>llvm.ctlz(i32 2) = 30</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5934
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5935	</div>
				5936
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5937	<!-- _______________________________________________________________________ -->
				5938	<div class="doc_subsubsection">
				5939	<a name="int_cttz">'<tt>llvm.cttz.*</tt>' Intrinsic</a>
				5940	</div>
				5941
				5942	<div class="doc_text">
				5943
				5944	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5945	<p>This is an overloaded intrinsic. You can use <tt>llvm.cttz</tt> on any
				5946	integer bit width. Not all targets support all bit widths however.</p>
				5947
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5948	<pre>
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5949	declare i8 @llvm.cttz.i8 (i8 <src>)
				5950	declare i16 @llvm.cttz.i16(i16 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5951	declare i32 @llvm.cttz.i32(i32 <src>)
Chandler Carruth	a228e39	2007-08-04 01:51:18 +0000	[diff] [blame]	5952	declare i64 @llvm.cttz.i64(i64 <src>)
				5953	declare i256 @llvm.cttz.i256(i256 <src>)
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5954	</pre>
				5955
				5956	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5957	<p>The '<tt>llvm.cttz</tt>' family of intrinsic functions counts the number of
				5958	trailing zeros.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5959
				5960	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5961	<p>The only argument is the value to be counted. The argument may be of any
				5962	integer type. The return type must match the argument type.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5963
				5964	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5965	<p>The '<tt>llvm.cttz</tt>' intrinsic counts the trailing (least significant)
				5966	zeros in a variable. If the src == 0 then the result is the size in bits of
				5967	the type of src. For example, <tt>llvm.cttz(2) = 1</tt>.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5968
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	5969	</div>
				5970
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	5971	<!-- ======================================================================= -->
				5972	<div class="doc_subsection">
				5973	<a name="int_overflow">Arithmetic with Overflow Intrinsics</a>
				5974	</div>
				5975
				5976	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5977
				5978	<p>LLVM provides intrinsics for some arithmetic with overflow operations.</p>
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	5979
				5980	</div>
				5981
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	5982	<!-- _______________________________________________________________________ -->
				5983	<div class="doc_subsubsection">
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	5984	<a name="int_sadd_overflow">'<tt>llvm.sadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	5985	</div>
				5986
				5987	<div class="doc_text">
				5988
				5989	<h5>Syntax:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	5990	<p>This is an overloaded intrinsic. You can use <tt>llvm.sadd.with.overflow</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	5991	on any integer bit width.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	5992
				5993	<pre>
				5994	declare {i16, i1} @llvm.sadd.with.overflow.i16(i16 %a, i16 %b)
				5995	declare {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
				5996	declare {i64, i1} @llvm.sadd.with.overflow.i64(i64 %a, i64 %b)
				5997	</pre>
				5998
				5999	<h5>Overview:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6000	<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6001	a signed addition of the two arguments, and indicate whether an overflow
				6002	occurred during the signed summation.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6003
				6004	<h5>Arguments:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6005	<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6006	be of integer types of any bit width, but they must have the same bit
				6007	width. The second element of the result structure must be of
				6008	type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
				6009	undergo signed addition.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6010
				6011	<h5>Semantics:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6012	<p>The '<tt>llvm.sadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6013	a signed addition of the two variables. They return a structure — the
				6014	first element of which is the signed summation, and the second element of
				6015	which is a bit specifying if the signed summation resulted in an
				6016	overflow.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6017
				6018	<h5>Examples:</h5>
				6019	<pre>
				6020	%res = call {i32, i1} @llvm.sadd.with.overflow.i32(i32 %a, i32 %b)
				6021	%sum = extractvalue {i32, i1} %res, 0
				6022	%obit = extractvalue {i32, i1} %res, 1
				6023	br i1 %obit, label %overflow, label %normal
				6024	</pre>
				6025
				6026	</div>
				6027
				6028	<!-- _______________________________________________________________________ -->
				6029	<div class="doc_subsubsection">
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	6030	<a name="int_uadd_overflow">'<tt>llvm.uadd.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6031	</div>
				6032
				6033	<div class="doc_text">
				6034
				6035	<h5>Syntax:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6036	<p>This is an overloaded intrinsic. You can use <tt>llvm.uadd.with.overflow</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6037	on any integer bit width.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6038
				6039	<pre>
				6040	declare {i16, i1} @llvm.uadd.with.overflow.i16(i16 %a, i16 %b)
				6041	declare {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
				6042	declare {i64, i1} @llvm.uadd.with.overflow.i64(i64 %a, i64 %b)
				6043	</pre>
				6044
				6045	<h5>Overview:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6046	<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6047	an unsigned addition of the two arguments, and indicate whether a carry
				6048	occurred during the unsigned summation.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6049
				6050	<h5>Arguments:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6051	<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6052	be of integer types of any bit width, but they must have the same bit
				6053	width. The second element of the result structure must be of
				6054	type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
				6055	undergo unsigned addition.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6056
				6057	<h5>Semantics:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6058	<p>The '<tt>llvm.uadd.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6059	an unsigned addition of the two arguments. They return a structure —
				6060	the first element of which is the sum, and the second element of which is a
				6061	bit specifying if the unsigned summation resulted in a carry.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6062
				6063	<h5>Examples:</h5>
				6064	<pre>
				6065	%res = call {i32, i1} @llvm.uadd.with.overflow.i32(i32 %a, i32 %b)
				6066	%sum = extractvalue {i32, i1} %res, 0
				6067	%obit = extractvalue {i32, i1} %res, 1
				6068	br i1 %obit, label %carry, label %normal
				6069	</pre>
				6070
				6071	</div>
				6072
				6073	<!-- _______________________________________________________________________ -->
				6074	<div class="doc_subsubsection">
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	6075	<a name="int_ssub_overflow">'<tt>llvm.ssub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6076	</div>
				6077
				6078	<div class="doc_text">
				6079
				6080	<h5>Syntax:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6081	<p>This is an overloaded intrinsic. You can use <tt>llvm.ssub.with.overflow</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6082	on any integer bit width.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6083
				6084	<pre>
				6085	declare {i16, i1} @llvm.ssub.with.overflow.i16(i16 %a, i16 %b)
				6086	declare {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
				6087	declare {i64, i1} @llvm.ssub.with.overflow.i64(i64 %a, i64 %b)
				6088	</pre>
				6089
				6090	<h5>Overview:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6091	<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6092	a signed subtraction of the two arguments, and indicate whether an overflow
				6093	occurred during the signed subtraction.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6094
				6095	<h5>Arguments:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6096	<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6097	be of integer types of any bit width, but they must have the same bit
				6098	width. The second element of the result structure must be of
				6099	type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
				6100	undergo signed subtraction.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6101
				6102	<h5>Semantics:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6103	<p>The '<tt>llvm.ssub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6104	a signed subtraction of the two arguments. They return a structure —
				6105	the first element of which is the subtraction, and the second element of
				6106	which is a bit specifying if the signed subtraction resulted in an
				6107	overflow.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6108
				6109	<h5>Examples:</h5>
				6110	<pre>
				6111	%res = call {i32, i1} @llvm.ssub.with.overflow.i32(i32 %a, i32 %b)
				6112	%sum = extractvalue {i32, i1} %res, 0
				6113	%obit = extractvalue {i32, i1} %res, 1
				6114	br i1 %obit, label %overflow, label %normal
				6115	</pre>
				6116
				6117	</div>
				6118
				6119	<!-- _______________________________________________________________________ -->
				6120	<div class="doc_subsubsection">
Bill Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	6121	<a name="int_usub_overflow">'<tt>llvm.usub.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6122	</div>
				6123
				6124	<div class="doc_text">
				6125
				6126	<h5>Syntax:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6127	<p>This is an overloaded intrinsic. You can use <tt>llvm.usub.with.overflow</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6128	on any integer bit width.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6129
				6130	<pre>
				6131	declare {i16, i1} @llvm.usub.with.overflow.i16(i16 %a, i16 %b)
				6132	declare {i32, i1} @llvm.usub.with.overflow.i32(i32 %a, i32 %b)
				6133	declare {i64, i1} @llvm.usub.with.overflow.i64(i64 %a, i64 %b)
				6134	</pre>
				6135
				6136	<h5>Overview:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6137	<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6138	an unsigned subtraction of the two arguments, and indicate whether an
				6139	overflow occurred during the unsigned subtraction.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6140
				6141	<h5>Arguments:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6142	<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6143	be of integer types of any bit width, but they must have the same bit
				6144	width. The second element of the result structure must be of
				6145	type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
				6146	undergo unsigned subtraction.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6147
				6148	<h5>Semantics:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6149	<p>The '<tt>llvm.usub.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6150	an unsigned subtraction of the two arguments. They return a structure —
				6151	the first element of which is the subtraction, and the second element of
				6152	which is a bit specifying if the unsigned subtraction resulted in an
				6153	overflow.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6154
				6155	<h5>Examples:</h5>
				6156	<pre>
				6157	%res = call {i32, i1} @llvm.usub.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 Wendling	3e1258b	2009-02-08 04:04:40 +0000	[diff] [blame]	6167	<a name="int_smul_overflow">'<tt>llvm.smul.with.overflow.*</tt>' Intrinsics</a>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6168	</div>
				6169
				6170	<div class="doc_text">
				6171
				6172	<h5>Syntax:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6173	<p>This is an overloaded intrinsic. You can use <tt>llvm.smul.with.overflow</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6174	on any integer bit width.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6175
				6176	<pre>
				6177	declare {i16, i1} @llvm.smul.with.overflow.i16(i16 %a, i16 %b)
				6178	declare {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
				6179	declare {i64, i1} @llvm.smul.with.overflow.i64(i64 %a, i64 %b)
				6180	</pre>
				6181
				6182	<h5>Overview:</h5>
				6183
				6184	<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6185	a signed multiplication of the two arguments, and indicate whether an
				6186	overflow occurred during the signed multiplication.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6187
				6188	<h5>Arguments:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6189	<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6190	be of integer types of any bit width, but they must have the same bit
				6191	width. The second element of the result structure must be of
				6192	type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
				6193	undergo signed multiplication.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6194
				6195	<h5>Semantics:</h5>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6196	<p>The '<tt>llvm.smul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6197	a signed multiplication of the two arguments. They return a structure —
				6198	the first element of which is the multiplication, and the second element of
				6199	which is a bit specifying if the signed multiplication resulted in an
				6200	overflow.</p>
Bill Wendling	3f8cebe	2009-02-08 01:40:31 +0000	[diff] [blame]	6201
				6202	<h5>Examples:</h5>
				6203	<pre>
				6204	%res = call {i32, i1} @llvm.smul.with.overflow.i32(i32 %a, i32 %b)
				6205	%sum = extractvalue {i32, i1} %res, 0
				6206	%obit = extractvalue {i32, i1} %res, 1
				6207	br i1 %obit, label %overflow, label %normal
				6208	</pre>
				6209
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6210	</div>
				6211
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6212	<!-- _______________________________________________________________________ -->
				6213	<div class="doc_subsubsection">
				6214	<a name="int_umul_overflow">'<tt>llvm.umul.with.overflow.*</tt>' Intrinsics</a>
				6215	</div>
				6216
				6217	<div class="doc_text">
				6218
				6219	<h5>Syntax:</h5>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6220	<p>This is an overloaded intrinsic. You can use <tt>llvm.umul.with.overflow</tt>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6221	on any integer bit width.</p>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6222
				6223	<pre>
				6224	declare {i16, i1} @llvm.umul.with.overflow.i16(i16 %a, i16 %b)
				6225	declare {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
				6226	declare {i64, i1} @llvm.umul.with.overflow.i64(i64 %a, i64 %b)
				6227	</pre>
				6228
				6229	<h5>Overview:</h5>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6230	<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6231	a unsigned multiplication of the two arguments, and indicate whether an
				6232	overflow occurred during the unsigned multiplication.</p>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6233
				6234	<h5>Arguments:</h5>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6235	<p>The arguments (%a and %b) and the first element of the result structure may
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6236	be of integer types of any bit width, but they must have the same bit
				6237	width. The second element of the result structure must be of
				6238	type <tt>i1</tt>. <tt>%a</tt> and <tt>%b</tt> are the two values that will
				6239	undergo unsigned multiplication.</p>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6240
				6241	<h5>Semantics:</h5>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6242	<p>The '<tt>llvm.umul.with.overflow</tt>' family of intrinsic functions perform
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6243	an unsigned multiplication of the two arguments. They return a structure
				6244	— the first element of which is the multiplication, and the second
				6245	element of which is a bit specifying if the unsigned multiplication resulted
				6246	in an overflow.</p>
Bill Wendling	bda98b6	2009-02-08 23:00:09 +0000	[diff] [blame]	6247
				6248	<h5>Examples:</h5>
				6249	<pre>
				6250	%res = call {i32, i1} @llvm.umul.with.overflow.i32(i32 %a, i32 %b)
				6251	%sum = extractvalue {i32, i1} %res, 0
				6252	%obit = extractvalue {i32, i1} %res, 1
				6253	br i1 %obit, label %overflow, label %normal
				6254	</pre>
				6255
				6256	</div>
				6257
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6258	<!-- ======================================================================= -->
				6259	<div class="doc_subsection">
				6260	<a name="int_debugger">Debugger Intrinsics</a>
				6261	</div>
				6262
				6263	<div class="doc_text">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6264
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6265	<p>The LLVM debugger intrinsics (which all start with <tt>llvm.dbg.</tt>
				6266	prefix), are described in
				6267	the <a href="SourceLevelDebugging.html#format_common_intrinsics">LLVM Source
				6268	Level Debugging</a> document.</p>
				6269
				6270	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6271
				6272	<!-- ======================================================================= -->
				6273	<div class="doc_subsection">
				6274	<a name="int_eh">Exception Handling Intrinsics</a>
				6275	</div>
				6276
				6277	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6278
				6279	<p>The LLVM exception handling intrinsics (which all start with
				6280	<tt>llvm.eh.</tt> prefix), are described in
				6281	the <a href="ExceptionHandling.html#format_common_intrinsics">LLVM Exception
				6282	Handling</a> document.</p>
				6283
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6284	</div>
				6285
				6286	<!-- ======================================================================= -->
				6287	<div class="doc_subsection">
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	6288	<a name="int_trampoline">Trampoline Intrinsic</a>
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6289	</div>
				6290
				6291	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6292
				6293	<p>This intrinsic makes it possible to excise one parameter, marked with
				6294	the <tt>nest</tt> attribute, from a function. The result is a callable
				6295	function pointer lacking the nest parameter - the caller does not need to
				6296	provide a value for it. Instead, the value to use is stored in advance in a
				6297	"trampoline", a block of memory usually allocated on the stack, which also
				6298	contains code to splice the nest value into the argument list. This is used
				6299	to implement the GCC nested function address extension.</p>
				6300
				6301	<p>For example, if the function is
				6302	<tt>i32 f(i8* nest %c, i32 %x, i32 %y)</tt> then the resulting function
				6303	pointer has signature <tt>i32 (i32, i32)*</tt>. It can be created as
				6304	follows:</p>
				6305
				6306	<div class="doc_code">
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6307	<pre>
Duncan Sands	7407a9f	2007-09-11 14:10:23 +0000	[diff] [blame]	6308	%tramp = alloca [10 x i8], align 4 ; size and alignment only correct for X86
				6309	%tramp1 = getelementptr [10 x i8]* %tramp, i32 0, i32 0
				6310	%p = call i8* @llvm.init.trampoline( i8* %tramp1, i8* bitcast (i32 (i8* nest , i32, i32)* @f to i8), i8 %nval )
				6311	%fp = bitcast i8* %p to i32 (i32, i32)*
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6312	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6313	</div>
				6314
				6315	<p>The call <tt>%val = call i32 %fp( i32 %x, i32 %y )</tt> is then equivalent
				6316	to <tt>%val = call i32 %f( i8* %nval, i32 %x, i32 %y )</tt>.</p>
				6317
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6318	</div>
				6319
				6320	<!-- _______________________________________________________________________ -->
				6321	<div class="doc_subsubsection">
				6322	<a name="int_it">'<tt>llvm.init.trampoline</tt>' Intrinsic</a>
				6323	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6324
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6325	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6326
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6327	<h5>Syntax:</h5>
				6328	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6329	declare i8* @llvm.init.trampoline(i8* <tramp>, i8* <func>, i8* <nval>)
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6330	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6331
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6332	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6333	<p>This fills the memory pointed to by <tt>tramp</tt> with code and returns a
				6334	function pointer suitable for executing it.</p>
				6335
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6336	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6337	<p>The <tt>llvm.init.trampoline</tt> intrinsic takes three arguments, all
				6338	pointers. The <tt>tramp</tt> argument must point to a sufficiently large and
				6339	sufficiently aligned block of memory; this memory is written to by the
				6340	intrinsic. Note that the size and the alignment are target-specific - LLVM
				6341	currently provides no portable way of determining them, so a front-end that
				6342	generates this intrinsic needs to have some target-specific knowledge.
				6343	The <tt>func</tt> argument must hold a function bitcast to
				6344	an <tt>i8*</tt>.</p>
				6345
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6346	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6347	<p>The block of memory pointed to by <tt>tramp</tt> is filled with target
				6348	dependent code, turning it into a function. A pointer to this function is
				6349	returned, but needs to be bitcast to an <a href="#int_trampoline">appropriate
				6350	function pointer type</a> before being called. The new function's signature
				6351	is the same as that of <tt>func</tt> with any arguments marked with
				6352	the <tt>nest</tt> attribute removed. At most one such <tt>nest</tt> argument
				6353	is allowed, and it must be of pointer type. Calling the new function is
				6354	equivalent to calling <tt>func</tt> with the same argument list, but
				6355	with <tt>nval</tt> used for the missing <tt>nest</tt> argument. If, after
				6356	calling <tt>llvm.init.trampoline</tt>, the memory pointed to
				6357	by <tt>tramp</tt> is modified, then the effect of any later call to the
				6358	returned function pointer is undefined.</p>
				6359
Duncan Sands	38947cd	2007-07-27 12:58:54 +0000	[diff] [blame]	6360	</div>
				6361
				6362	<!-- ======================================================================= -->
				6363	<div class="doc_subsection">
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6364	<a name="int_atomics">Atomic Operations and Synchronization Intrinsics</a>
				6365	</div>
				6366
				6367	<div class="doc_text">
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6368
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6369	<p>These intrinsic functions expand the "universal IR" of LLVM to represent
				6370	hardware constructs for atomic operations and memory synchronization. This
				6371	provides an interface to the hardware, not an interface to the programmer. It
				6372	is aimed at a low enough level to allow any programming models or APIs
				6373	(Application Programming Interfaces) which need atomic behaviors to map
				6374	cleanly onto it. It is also modeled primarily on hardware behavior. Just as
				6375	hardware provides a "universal IR" for source languages, it also provides a
				6376	starting point for developing a "universal" atomic operation and
				6377	synchronization IR.</p>
				6378
				6379	<p>These do <em>not</em> form an API such as high-level threading libraries,
				6380	software transaction memory systems, atomic primitives, and intrinsic
				6381	functions as found in BSD, GNU libc, atomic_ops, APR, and other system and
				6382	application libraries. The hardware interface provided by LLVM should allow
				6383	a clean implementation of all of these APIs and parallel programming models.
				6384	No one model or paradigm should be selected above others unless the hardware
				6385	itself ubiquitously does so.</p>
				6386
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6387	</div>
				6388
				6389	<!-- _______________________________________________________________________ -->
				6390	<div class="doc_subsubsection">
				6391	<a name="int_memory_barrier">'<tt>llvm.memory.barrier</tt>' Intrinsic</a>
				6392	</div>
				6393	<div class="doc_text">
				6394	<h5>Syntax:</h5>
				6395	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6396	declare void @llvm.memory.barrier( i1 <ll>, i1 <ls>, i1 <sl>, i1 <ss>, i1 <device> )
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6397	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6398
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6399	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6400	<p>The <tt>llvm.memory.barrier</tt> intrinsic guarantees ordering between
				6401	specific pairs of memory access types.</p>
				6402
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6403	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6404	<p>The <tt>llvm.memory.barrier</tt> intrinsic requires five boolean arguments.
				6405	The first four arguments enables a specific barrier as listed below. The
				6406	fith argument specifies that the barrier applies to io or device or uncached
				6407	memory.</p>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6408
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6409	<ul>
				6410	<li><tt>ll</tt>: load-load barrier</li>
				6411	<li><tt>ls</tt>: load-store barrier</li>
				6412	<li><tt>sl</tt>: store-load barrier</li>
				6413	<li><tt>ss</tt>: store-store barrier</li>
				6414	<li><tt>device</tt>: barrier applies to device and uncached memory also.</li>
				6415	</ul>
				6416
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6417	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6418	<p>This intrinsic causes the system to enforce some ordering constraints upon
				6419	the loads and stores of the program. This barrier does not
				6420	indicate <em>when</em> any events will occur, it only enforces
				6421	an <em>order</em> in which they occur. For any of the specified pairs of load
				6422	and store operations (f.ex. load-load, or store-load), all of the first
				6423	operations preceding the barrier will complete before any of the second
				6424	operations succeeding the barrier begin. Specifically the semantics for each
				6425	pairing is as follows:</p>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6426
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6427	<ul>
				6428	<li><tt>ll</tt>: All loads before the barrier must complete before any load
				6429	after the barrier begins.</li>
				6430	<li><tt>ls</tt>: All loads before the barrier must complete before any
				6431	store after the barrier begins.</li>
				6432	<li><tt>ss</tt>: All stores before the barrier must complete before any
				6433	store after the barrier begins.</li>
				6434	<li><tt>sl</tt>: All stores before the barrier must complete before any
				6435	load after the barrier begins.</li>
				6436	</ul>
				6437
				6438	<p>These semantics are applied with a logical "and" behavior when more than one
				6439	is enabled in a single memory barrier intrinsic.</p>
				6440
				6441	<p>Backends may implement stronger barriers than those requested when they do
				6442	not support as fine grained a barrier as requested. Some architectures do
				6443	not need all types of barriers and on such architectures, these become
				6444	noops.</p>
				6445
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6446	<h5>Example:</h5>
				6447	<pre>
				6448	%ptr = malloc i32
				6449	store i32 4, %ptr
				6450
				6451	%result1 = load i32* %ptr <i>; yields {i32}:result1 = 4</i>
				6452	call void @llvm.memory.barrier( i1 false, i1 true, i1 false, i1 false )
				6453	<i>; guarantee the above finishes</i>
				6454	store i32 8, %ptr <i>; before this begins</i>
				6455	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6456
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6457	</div>
				6458
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6459	<!-- _______________________________________________________________________ -->
				6460	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6461	<a name="int_atomic_cmp_swap">'<tt>llvm.atomic.cmp.swap.*</tt>' Intrinsic</a>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6462	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6463
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6464	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6465
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6466	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6467	<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.cmp.swap</tt> on
				6468	any integer bit width and for different address spaces. Not all targets
				6469	support all bit widths however.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6470
				6471	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6472	declare i8 @llvm.atomic.cmp.swap.i8.p0i8( i8* <ptr>, i8 <cmp>, i8 <val> )
				6473	declare i16 @llvm.atomic.cmp.swap.i16.p0i16( i16* <ptr>, i16 <cmp>, i16 <val> )
				6474	declare i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* <ptr>, i32 <cmp>, i32 <val> )
				6475	declare i64 @llvm.atomic.cmp.swap.i64.p0i64( i64* <ptr>, i64 <cmp>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6476	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6477
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6478	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6479	<p>This loads a value in memory and compares it to a given value. If they are
				6480	equal, it stores a new value into the memory.</p>
				6481
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6482	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6483	<p>The <tt>llvm.atomic.cmp.swap</tt> intrinsic takes three arguments. The result
				6484	as well as both <tt>cmp</tt> and <tt>val</tt> must be integer values with the
				6485	same bit width. The <tt>ptr</tt> argument must be a pointer to a value of
				6486	this integer type. While any bit width integer may be used, targets may only
				6487	lower representations they support in hardware.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6488
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6489	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6490	<p>This entire intrinsic must be executed atomically. It first loads the value
				6491	in memory pointed to by <tt>ptr</tt> and compares it with the
				6492	value <tt>cmp</tt>. If they are equal, <tt>val</tt> is stored into the
				6493	memory. The loaded value is yielded in all cases. This provides the
				6494	equivalent of an atomic compare-and-swap operation within the SSA
				6495	framework.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6496
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6497	<h5>Examples:</h5>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6498	<pre>
				6499	%ptr = malloc i32
				6500	store i32 4, %ptr
				6501
				6502	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6503	%result1 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 4, %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6504	<i>; yields {i32}:result1 = 4</i>
				6505	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				6506	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				6507
				6508	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6509	%result2 = call i32 @llvm.atomic.cmp.swap.i32.p0i32( i32* %ptr, i32 5, %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6510	<i>; yields {i32}:result2 = 8</i>
				6511	%stored2 = icmp eq i32 %result2, 5 <i>; yields {i1}:stored2 = false</i>
				6512
				6513	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 8</i>
				6514	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6515
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6516	</div>
				6517
				6518	<!-- _______________________________________________________________________ -->
				6519	<div class="doc_subsubsection">
				6520	<a name="int_atomic_swap">'<tt>llvm.atomic.swap.*</tt>' Intrinsic</a>
				6521	</div>
				6522	<div class="doc_text">
				6523	<h5>Syntax:</h5>
				6524
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6525	<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.swap</tt> on any
				6526	integer bit width. Not all targets support all bit widths however.</p>
				6527
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6528	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6529	declare i8 @llvm.atomic.swap.i8.p0i8( i8* <ptr>, i8 <val> )
				6530	declare i16 @llvm.atomic.swap.i16.p0i16( i16* <ptr>, i16 <val> )
				6531	declare i32 @llvm.atomic.swap.i32.p0i32( i32* <ptr>, i32 <val> )
				6532	declare i64 @llvm.atomic.swap.i64.p0i64( i64* <ptr>, i64 <val> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6533	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6534
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6535	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6536	<p>This intrinsic loads the value stored in memory at <tt>ptr</tt> and yields
				6537	the value from memory. It then stores the value in <tt>val</tt> in the memory
				6538	at <tt>ptr</tt>.</p>
				6539
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6540	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6541	<p>The <tt>llvm.atomic.swap</tt> intrinsic takes two arguments. Both
				6542	the <tt>val</tt> argument and the result must be integers of the same bit
				6543	width. The first argument, <tt>ptr</tt>, must be a pointer to a value of this
				6544	integer type. The targets may only lower integer representations they
				6545	support.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6546
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6547	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6548	<p>This intrinsic loads the value pointed to by <tt>ptr</tt>, yields it, and
				6549	stores <tt>val</tt> back into <tt>ptr</tt> atomically. This provides the
				6550	equivalent of an atomic swap operation within the SSA framework.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6551
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6552	<h5>Examples:</h5>
				6553	<pre>
				6554	%ptr = malloc i32
				6555	store i32 4, %ptr
				6556
				6557	%val1 = add i32 4, 4
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6558	%result1 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val1 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6559	<i>; yields {i32}:result1 = 4</i>
				6560	%stored1 = icmp eq i32 %result1, 4 <i>; yields {i1}:stored1 = true</i>
				6561	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 8</i>
				6562
				6563	%val2 = add i32 1, 1
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6564	%result2 = call i32 @llvm.atomic.swap.i32.p0i32( i32* %ptr, i32 %val2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6565	<i>; yields {i32}:result2 = 8</i>
				6566
				6567	%stored2 = icmp eq i32 %result2, 8 <i>; yields {i1}:stored2 = true</i>
				6568	%memval2 = load i32* %ptr <i>; yields {i32}:memval2 = 2</i>
				6569	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6570
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6571	</div>
				6572
				6573	<!-- _______________________________________________________________________ -->
				6574	<div class="doc_subsubsection">
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6575	<a name="int_atomic_load_add">'<tt>llvm.atomic.load.add.*</tt>' Intrinsic</a>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6576
				6577	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6578
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6579	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6580
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6581	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6582	<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.add</tt> on
				6583	any integer bit width. Not all targets support all bit widths however.</p>
				6584
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6585	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6586	declare i8 @llvm.atomic.load.add.i8..p0i8( i8* <ptr>, i8 <delta> )
				6587	declare i16 @llvm.atomic.load.add.i16..p0i16( i16* <ptr>, i16 <delta> )
				6588	declare i32 @llvm.atomic.load.add.i32..p0i32( i32* <ptr>, i32 <delta> )
				6589	declare i64 @llvm.atomic.load.add.i64..p0i64( i64* <ptr>, i64 <delta> )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6590	</pre>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6591
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6592	<h5>Overview:</h5>
				6593	<p>This intrinsic adds <tt>delta</tt> to the value stored in memory
				6594	at <tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
				6595
				6596	<h5>Arguments:</h5>
				6597	<p>The intrinsic takes two arguments, the first a pointer to an integer value
				6598	and the second an integer value. The result is also an integer value. These
				6599	integer types can have any bit width, but they must all have the same bit
				6600	width. The targets may only lower integer representations they support.</p>
				6601
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6602	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6603	<p>This intrinsic does a series of operations atomically. It first loads the
				6604	value stored at <tt>ptr</tt>. It then adds <tt>delta</tt>, stores the result
				6605	to <tt>ptr</tt>. It yields the original value stored at <tt>ptr</tt>.</p>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6606
				6607	<h5>Examples:</h5>
				6608	<pre>
				6609	%ptr = malloc i32
				6610	store i32 4, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6611	%result1 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 4 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6612	<i>; yields {i32}:result1 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6613	%result2 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 2 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6614	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6615	%result3 = call i32 @llvm.atomic.load.add.i32.p0i32( i32* %ptr, i32 5 )
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6616	<i>; yields {i32}:result3 = 10</i>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6617	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 15</i>
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6618	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6619
Andrew Lenharth	e44f390	2008-02-21 06:45:13 +0000	[diff] [blame]	6620	</div>
				6621
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6622	<!-- _______________________________________________________________________ -->
				6623	<div class="doc_subsubsection">
				6624	<a name="int_atomic_load_sub">'<tt>llvm.atomic.load.sub.*</tt>' Intrinsic</a>
				6625
				6626	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6627
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6628	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6629
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6630	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6631	<p>This is an overloaded intrinsic. You can use <tt>llvm.atomic.load.sub</tt> on
				6632	any integer bit width and for different address spaces. Not all targets
				6633	support all bit widths however.</p>
				6634
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6635	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6636	declare i8 @llvm.atomic.load.sub.i8.p0i32( i8* <ptr>, i8 <delta> )
				6637	declare i16 @llvm.atomic.load.sub.i16.p0i32( i16* <ptr>, i16 <delta> )
				6638	declare i32 @llvm.atomic.load.sub.i32.p0i32( i32* <ptr>, i32 <delta> )
				6639	declare i64 @llvm.atomic.load.sub.i64.p0i32( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6640	</pre>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6641
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6642	<h5>Overview:</h5>
				6643	<p>This intrinsic subtracts <tt>delta</tt> to the value stored in memory at
				6644	<tt>ptr</tt>. It yields the original value at <tt>ptr</tt>.</p>
				6645
				6646	<h5>Arguments:</h5>
				6647	<p>The intrinsic takes two arguments, the first a pointer to an integer value
				6648	and the second an integer value. The result is also an integer value. These
				6649	integer types can have any bit width, but they must all have the same bit
				6650	width. The targets may only lower integer representations they support.</p>
				6651
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6652	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6653	<p>This intrinsic does a series of operations atomically. It first loads the
				6654	value stored at <tt>ptr</tt>. It then subtracts <tt>delta</tt>, stores the
				6655	result to <tt>ptr</tt>. It yields the original value stored
				6656	at <tt>ptr</tt>.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6657
				6658	<h5>Examples:</h5>
				6659	<pre>
				6660	%ptr = malloc i32
				6661	store i32 8, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6662	%result1 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 4 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6663	<i>; yields {i32}:result1 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6664	%result2 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 2 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6665	<i>; yields {i32}:result2 = 4</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6666	%result3 = call i32 @llvm.atomic.load.sub.i32.p0i32( i32* %ptr, i32 5 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6667	<i>; yields {i32}:result3 = 2</i>
				6668	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = -3</i>
				6669	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6670
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6671	</div>
				6672
				6673	<!-- _______________________________________________________________________ -->
				6674	<div class="doc_subsubsection">
				6675	<a name="int_atomic_load_and">'<tt>llvm.atomic.load.and.*</tt>' Intrinsic</a><br>
				6676	<a name="int_atomic_load_nand">'<tt>llvm.atomic.load.nand.*</tt>' Intrinsic</a><br>
				6677	<a name="int_atomic_load_or">'<tt>llvm.atomic.load.or.*</tt>' Intrinsic</a><br>
				6678	<a name="int_atomic_load_xor">'<tt>llvm.atomic.load.xor.*</tt>' Intrinsic</a><br>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6679	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6680
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6681	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6682
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6683	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6684	<p>These are overloaded intrinsics. You can
				6685	use <tt>llvm.atomic.load_and</tt>, <tt>llvm.atomic.load_nand</tt>,
				6686	<tt>llvm.atomic.load_or</tt>, and <tt>llvm.atomic.load_xor</tt> on any integer
				6687	bit width and for different address spaces. Not all targets support all bit
				6688	widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6689
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6690	<pre>
				6691	declare i8 @llvm.atomic.load.and.i8.p0i8( i8* <ptr>, i8 <delta> )
				6692	declare i16 @llvm.atomic.load.and.i16.p0i16( i16* <ptr>, i16 <delta> )
				6693	declare i32 @llvm.atomic.load.and.i32.p0i32( i32* <ptr>, i32 <delta> )
				6694	declare i64 @llvm.atomic.load.and.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6695	</pre>
				6696
				6697	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6698	declare i8 @llvm.atomic.load.or.i8.p0i8( i8* <ptr>, i8 <delta> )
				6699	declare i16 @llvm.atomic.load.or.i16.p0i16( i16* <ptr>, i16 <delta> )
				6700	declare i32 @llvm.atomic.load.or.i32.p0i32( i32* <ptr>, i32 <delta> )
				6701	declare i64 @llvm.atomic.load.or.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6702	</pre>
				6703
				6704	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6705	declare i8 @llvm.atomic.load.nand.i8.p0i32( i8* <ptr>, i8 <delta> )
				6706	declare i16 @llvm.atomic.load.nand.i16.p0i32( i16* <ptr>, i16 <delta> )
				6707	declare i32 @llvm.atomic.load.nand.i32.p0i32( i32* <ptr>, i32 <delta> )
				6708	declare i64 @llvm.atomic.load.nand.i64.p0i32( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6709	</pre>
				6710
				6711	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6712	declare i8 @llvm.atomic.load.xor.i8.p0i32( i8* <ptr>, i8 <delta> )
				6713	declare i16 @llvm.atomic.load.xor.i16.p0i32( i16* <ptr>, i16 <delta> )
				6714	declare i32 @llvm.atomic.load.xor.i32.p0i32( i32* <ptr>, i32 <delta> )
				6715	declare i64 @llvm.atomic.load.xor.i64.p0i32( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6716	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6717
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6718	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6719	<p>These intrinsics bitwise the operation (and, nand, or, xor) <tt>delta</tt> to
				6720	the value stored in memory at <tt>ptr</tt>. It yields the original value
				6721	at <tt>ptr</tt>.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6722
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6723	<h5>Arguments:</h5>
				6724	<p>These intrinsics take two arguments, the first a pointer to an integer value
				6725	and the second an integer value. The result is also an integer value. These
				6726	integer types can have any bit width, but they must all have the same bit
				6727	width. The targets may only lower integer representations they support.</p>
				6728
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6729	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6730	<p>These intrinsics does a series of operations atomically. They first load the
				6731	value stored at <tt>ptr</tt>. They then do the bitwise
				6732	operation <tt>delta</tt>, store the result to <tt>ptr</tt>. They yield the
				6733	original value stored at <tt>ptr</tt>.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6734
				6735	<h5>Examples:</h5>
				6736	<pre>
				6737	%ptr = malloc i32
				6738	store i32 0x0F0F, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6739	%result0 = call i32 @llvm.atomic.load.nand.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6740	<i>; yields {i32}:result0 = 0x0F0F</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6741	%result1 = call i32 @llvm.atomic.load.and.i32.p0i32( i32* %ptr, i32 0xFF )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6742	<i>; yields {i32}:result1 = 0xFFFFFFF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6743	%result2 = call i32 @llvm.atomic.load.or.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6744	<i>; yields {i32}:result2 = 0xF0</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6745	%result3 = call i32 @llvm.atomic.load.xor.i32.p0i32( i32* %ptr, i32 0F )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6746	<i>; yields {i32}:result3 = FF</i>
				6747	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = F0</i>
				6748	</pre>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6749
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6750	</div>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6751
				6752	<!-- _______________________________________________________________________ -->
				6753	<div class="doc_subsubsection">
				6754	<a name="int_atomic_load_max">'<tt>llvm.atomic.load.max.*</tt>' Intrinsic</a><br>
				6755	<a name="int_atomic_load_min">'<tt>llvm.atomic.load.min.*</tt>' Intrinsic</a><br>
				6756	<a name="int_atomic_load_umax">'<tt>llvm.atomic.load.umax.*</tt>' Intrinsic</a><br>
				6757	<a name="int_atomic_load_umin">'<tt>llvm.atomic.load.umin.*</tt>' Intrinsic</a><br>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6758	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6759
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6760	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6761
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6762	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6763	<p>These are overloaded intrinsics. You can use <tt>llvm.atomic.load_max</tt>,
				6764	<tt>llvm.atomic.load_min</tt>, <tt>llvm.atomic.load_umax</tt>, and
				6765	<tt>llvm.atomic.load_umin</tt> on any integer bit width and for different
				6766	address spaces. Not all targets support all bit widths however.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6767
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6768	<pre>
				6769	declare i8 @llvm.atomic.load.max.i8.p0i8( i8* <ptr>, i8 <delta> )
				6770	declare i16 @llvm.atomic.load.max.i16.p0i16( i16* <ptr>, i16 <delta> )
				6771	declare i32 @llvm.atomic.load.max.i32.p0i32( i32* <ptr>, i32 <delta> )
				6772	declare i64 @llvm.atomic.load.max.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6773	</pre>
				6774
				6775	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6776	declare i8 @llvm.atomic.load.min.i8.p0i8( i8* <ptr>, i8 <delta> )
				6777	declare i16 @llvm.atomic.load.min.i16.p0i16( i16* <ptr>, i16 <delta> )
				6778	declare i32 @llvm.atomic.load.min.i32..p0i32( i32* <ptr>, i32 <delta> )
				6779	declare i64 @llvm.atomic.load.min.i64..p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6780	</pre>
				6781
				6782	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6783	declare i8 @llvm.atomic.load.umax.i8.p0i8( i8* <ptr>, i8 <delta> )
				6784	declare i16 @llvm.atomic.load.umax.i16.p0i16( i16* <ptr>, i16 <delta> )
				6785	declare i32 @llvm.atomic.load.umax.i32.p0i32( i32* <ptr>, i32 <delta> )
				6786	declare i64 @llvm.atomic.load.umax.i64.p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6787	</pre>
				6788
				6789	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6790	declare i8 @llvm.atomic.load.umin.i8..p0i8( i8* <ptr>, i8 <delta> )
				6791	declare i16 @llvm.atomic.load.umin.i16.p0i16( i16* <ptr>, i16 <delta> )
				6792	declare i32 @llvm.atomic.load.umin.i32..p0i32( i32* <ptr>, i32 <delta> )
				6793	declare i64 @llvm.atomic.load.umin.i64..p0i64( i64* <ptr>, i64 <delta> )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6794	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6795
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6796	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6797	<p>These intrinsics takes the signed or unsigned minimum or maximum of
				6798	<tt>delta</tt> and the value stored in memory at <tt>ptr</tt>. It yields the
				6799	original value at <tt>ptr</tt>.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6800
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6801	<h5>Arguments:</h5>
				6802	<p>These intrinsics take two arguments, the first a pointer to an integer value
				6803	and the second an integer value. The result is also an integer value. These
				6804	integer types can have any bit width, but they must all have the same bit
				6805	width. The targets may only lower integer representations they support.</p>
				6806
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6807	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6808	<p>These intrinsics does a series of operations atomically. They first load the
				6809	value stored at <tt>ptr</tt>. They then do the signed or unsigned min or
				6810	max <tt>delta</tt> and the value, store the result to <tt>ptr</tt>. They
				6811	yield the original value stored at <tt>ptr</tt>.</p>
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6812
				6813	<h5>Examples:</h5>
				6814	<pre>
				6815	%ptr = malloc i32
				6816	store i32 7, %ptr
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6817	%result0 = call i32 @llvm.atomic.load.min.i32.p0i32( i32* %ptr, i32 -2 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6818	<i>; yields {i32}:result0 = 7</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6819	%result1 = call i32 @llvm.atomic.load.max.i32.p0i32( i32* %ptr, i32 8 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6820	<i>; yields {i32}:result1 = -2</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6821	%result2 = call i32 @llvm.atomic.load.umin.i32.p0i32( i32* %ptr, i32 10 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6822	<i>; yields {i32}:result2 = 8</i>
Mon P Wang	ce3ac89	2008-07-30 04:36:53 +0000	[diff] [blame]	6823	%result3 = call i32 @llvm.atomic.load.umax.i32.p0i32( i32* %ptr, i32 30 )
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6824	<i>; yields {i32}:result3 = 8</i>
				6825	%memval1 = load i32* %ptr <i>; yields {i32}:memval1 = 30</i>
				6826	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6827
Mon P Wang	6bde9ec	2008-06-25 08:15:39 +0000	[diff] [blame]	6828	</div>
Andrew Lenharth	785610d	2008-02-16 01:24:58 +0000	[diff] [blame]	6829
				6830	<!-- ======================================================================= -->
				6831	<div class="doc_subsection">
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6832	<a name="int_general">General Intrinsics</a>
				6833	</div>
				6834
				6835	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6836
				6837	<p>This class of intrinsics is designed to be generic and has no specific
				6838	purpose.</p>
				6839
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6840	</div>
				6841
				6842	<!-- _______________________________________________________________________ -->
				6843	<div class="doc_subsubsection">
				6844	<a name="int_var_annotation">'<tt>llvm.var.annotation</tt>' Intrinsic</a>
				6845	</div>
				6846
				6847	<div class="doc_text">
				6848
				6849	<h5>Syntax:</h5>
				6850	<pre>
				6851	declare void @llvm.var.annotation(i8* <val>, i8* <str>, i8* <str>, i32 <int> )
				6852	</pre>
				6853
				6854	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6855	<p>The '<tt>llvm.var.annotation</tt>' intrinsic.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6856
				6857	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6858	<p>The first argument is a pointer to a value, the second is a pointer to a
				6859	global string, the third is a pointer to a global string which is the source
				6860	file name, and the last argument is the line number.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6861
				6862	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6863	<p>This intrinsic allows annotation of local variables with arbitrary strings.
				6864	This can be useful for special purpose optimizations that want to look for
				6865	these annotations. These have no other defined use, they are ignored by code
				6866	generation and optimization.</p>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6867
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6868	</div>
				6869
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6870	<!-- _______________________________________________________________________ -->
				6871	<div class="doc_subsubsection">
Tanya Lattner	c9869b1	2007-09-21 23:57:59 +0000	[diff] [blame]	6872	<a name="int_annotation">'<tt>llvm.annotation.*</tt>' Intrinsic</a>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6873	</div>
				6874
				6875	<div class="doc_text">
				6876
				6877	<h5>Syntax:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6878	<p>This is an overloaded intrinsic. You can use '<tt>llvm.annotation</tt>' on
				6879	any integer bit width.</p>
				6880
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6881	<pre>
Tanya Lattner	09161fe	2007-09-22 00:03:01 +0000	[diff] [blame]	6882	declare i8 @llvm.annotation.i8(i8 <val>, i8* <str>, i8* <str>, i32 <int> )
				6883	declare i16 @llvm.annotation.i16(i16 <val>, i8* <str>, i8* <str>, i32 <int> )
				6884	declare i32 @llvm.annotation.i32(i32 <val>, i8* <str>, i8* <str>, i32 <int> )
				6885	declare i64 @llvm.annotation.i64(i64 <val>, i8* <str>, i8* <str>, i32 <int> )
				6886	declare i256 @llvm.annotation.i256(i256 <val>, i8* <str>, i8* <str>, i32 <int> )
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6887	</pre>
				6888
				6889	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6890	<p>The '<tt>llvm.annotation</tt>' intrinsic.</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6891
				6892	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6893	<p>The first argument is an integer value (result of some expression), the
				6894	second is a pointer to a global string, the third is a pointer to a global
				6895	string which is the source file name, and the last argument is the line
				6896	number. It returns the value of the first argument.</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6897
				6898	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6899	<p>This intrinsic allows annotations to be put on arbitrary expressions with
				6900	arbitrary strings. This can be useful for special purpose optimizations that
				6901	want to look for these annotations. These have no other defined use, they
				6902	are ignored by code generation and optimization.</p>
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6903
Tanya Lattner	b306a9e	2007-09-21 22:59:12 +0000	[diff] [blame]	6904	</div>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6905
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6906	<!-- _______________________________________________________________________ -->
				6907	<div class="doc_subsubsection">
				6908	<a name="int_trap">'<tt>llvm.trap</tt>' Intrinsic</a>
				6909	</div>
				6910
				6911	<div class="doc_text">
				6912
				6913	<h5>Syntax:</h5>
				6914	<pre>
				6915	declare void @llvm.trap()
				6916	</pre>
				6917
				6918	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6919	<p>The '<tt>llvm.trap</tt>' intrinsic.</p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6920
				6921	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6922	<p>None.</p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6923
				6924	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6925	<p>This intrinsics is lowered to the target dependent trap instruction. If the
				6926	target does not have a trap instruction, this intrinsic will be lowered to
				6927	the call of the <tt>abort()</tt> function.</p>
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6928
Anton Korobeynikov	e6e764f	2008-01-15 22:31:34 +0000	[diff] [blame]	6929	</div>
				6930
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6931	<!-- _______________________________________________________________________ -->
				6932	<div class="doc_subsubsection">
Misha Brukman	5dd7f4d	2008-11-22 23:55:29 +0000	[diff] [blame]	6933	<a name="int_stackprotector">'<tt>llvm.stackprotector</tt>' Intrinsic</a>
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6934	</div>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6935
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6936	<div class="doc_text">
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6937
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6938	<h5>Syntax:</h5>
				6939	<pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6940	declare void @llvm.stackprotector( i8* <guard>, i8** <slot> )
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6941	</pre>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6942
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6943	<h5>Overview:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6944	<p>The <tt>llvm.stackprotector</tt> intrinsic takes the <tt>guard</tt> and
				6945	stores it onto the stack at <tt>slot</tt>. The stack slot is adjusted to
				6946	ensure that it is placed on the stack before local variables.</p>
				6947
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6948	<h5>Arguments:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6949	<p>The <tt>llvm.stackprotector</tt> intrinsic requires two pointer
				6950	arguments. The first argument is the value loaded from the stack
				6951	guard <tt>@__stack_chk_guard</tt>. The second variable is an <tt>alloca</tt>
				6952	that has enough space to hold the value of the guard.</p>
				6953
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6954	<h5>Semantics:</h5>
Bill Wendling	f85859d	2009-07-20 02:29:24 +0000	[diff] [blame]	6955	<p>This intrinsic causes the prologue/epilogue inserter to force the position of
				6956	the <tt>AllocaInst</tt> stack slot to be before local variables on the
				6957	stack. This is to ensure that if a local variable on the stack is
				6958	overwritten, it will destroy the value of the guard. When the function exits,
				6959	the guard on the stack is checked against the original guard. If they're
				6960	different, then the program aborts by calling the <tt>__stack_chk_fail()</tt>
				6961	function.</p>
				6962
Bill Wendling	e416459	2008-11-19 05:56:17 +0000	[diff] [blame]	6963	</div>
				6964
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6965	<!-- *********************************************************************** -->
				6966	<hr>
				6967	<address>
				6968	<a href="http://jigsaw.w3.org/css-validator/check/referer"><img
Misha Brukman	947321d	2008-12-11 17:34:48 +0000	[diff] [blame]	6969	src="http://jigsaw.w3.org/css-validator/images/vcss-blue" alt="Valid CSS"></a>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6970	<a href="http://validator.w3.org/check/referer"><img
Misha Brukman	947321d	2008-12-11 17:34:48 +0000	[diff] [blame]	6971	src="http://www.w3.org/Icons/valid-html401-blue" alt="Valid HTML 4.01"></a>
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6972
				6973	<a href="mailto:sabre@nondot.org">Chris Lattner</a><br>
				6974	<a href="http://llvm.org">The LLVM Compiler Infrastructure</a><br>
				6975	Last modified: $Date$
				6976	</address>
Chris Lattner	08497ce	2008-01-04 04:33:49 +0000	[diff] [blame]	6977
Dan Gohman	f17a25c	2007-07-18 16:29:46 +0000	[diff] [blame]	6978	</body>
				6979	</html>