Commit Graph

4711 Commits

Author SHA1 Message Date
Owen Anderson 272ff94916 When TCO is turned on, it is possible to end up with aliasing FrameIndex's. Therefore,
CombinerAA cannot assume that different FrameIndex's never alias, but can instead use
MachineFrameInfo to get the actual offsets of these slots and check for actual aliasing.

This fixes CodeGen/X86/2010-02-19-TailCallRetAddrBug.ll and CodeGen/X86/tailcallstack64.ll
when CombinerAA is enabled, modulo a different register allocation sequence.

llvm-svn: 114348
2010-09-20 20:39:59 +00:00
Owen Anderson 7b8d2ae912 Revert r114312 while I sort out some issues.
llvm-svn: 114313
2010-09-19 21:01:26 +00:00
Owen Anderson ff82f8a35b Tentatively enabled DAGCombiner Alias Analysis by default. As far as I know,
r114268 fixed the last of the blockers to enabling it.  I will be monitoring
for failures.

llvm-svn: 114312
2010-09-19 19:51:55 +00:00
Owen Anderson b92b13d8a0 Invert the logic of reachesChainWithoutSideEffects(). What we want to check is that there is
NO path to the destination containing side effects, not that SOME path contains no side effects.
In  practice, this only manifests with CombinerAA enabled, because otherwise the chain has little
to no branching, so "any" is effectively equivalent to "all".

llvm-svn: 114268
2010-09-18 04:45:14 +00:00
Devang Patel 46b96c4ba0 Check bb to ensure that alloca is in separate basic block.
This fixes funcargs.exp regression reported by gdb testsuite.

llvm-svn: 113992
2010-09-15 18:13:55 +00:00
Devang Patel da25de8096 If dbg.declare from non-entry block is using alloca from entry block then use offset available in StaticAllocaMap to emit DBG_VALUE. Right now, this has no material impact because varible info also collected using offset table maintained in machine module info.
llvm-svn: 113967
2010-09-15 14:48:53 +00:00
Devang Patel e4682fa8e2 Use frame index, if available for byval argument while lowering dbg_declare. Otherwise let getRegForValue() find register for this argument.
llvm-svn: 113843
2010-09-14 20:29:31 +00:00
Michael J. Spencer 93c9b2ea93 Revert "CMake: Get rid of LLVMLibDeps.cmake and export the libraries normally."
This reverts commit r113632

Conflicts:

	cmake/modules/AddLLVM.cmake

llvm-svn: 113819
2010-09-13 23:59:48 +00:00
Eric Christopher 79127ab3f5 Silence more warnings. Two more unused variables.
llvm-svn: 113771
2010-09-13 18:30:57 +00:00
John Thompson 1094c80281 Added skeleton for inline asm multiple alternative constraint support.
llvm-svn: 113766
2010-09-13 18:15:37 +00:00
Michael J. Spencer dc38d36ccb CMake: Get rid of LLVMLibDeps.cmake and export the libraries normally.
llvm-svn: 113632
2010-09-10 21:14:25 +00:00
Devang Patel 6095d818e5 Add DEBUG message.
llvm-svn: 113614
2010-09-10 20:32:09 +00:00
Evan Cheng bf4070756f Teach if-converter to be more careful with predicating instructions that would
take multiple cycles to decode.
For the current if-converter clients (actually only ARM), the instructions that
are predicated on false are not nops. They would still take machine cycles to
decode. Micro-coded instructions such as LDM / STM can potentially take multiple
cycles to decode. If-converter should take treat them as non-micro-coded
simple instructions.

llvm-svn: 113570
2010-09-10 01:29:16 +00:00
Chris Lattner eeba0c73e5 implement rdar://6653118 - fastisel should fold loads where possible.
Since mem2reg isn't run at -O0, we get a ton of reloads from the stack,
for example, before, this code:

int foo(int x, int y, int z) {
  return x+y+z;
}

used to compile into:

_foo:                                   ## @foo
	subq	$12, %rsp
	movl	%edi, 8(%rsp)
	movl	%esi, 4(%rsp)
	movl	%edx, (%rsp)
	movl	8(%rsp), %edx
	movl	4(%rsp), %esi
	addl	%edx, %esi
	movl	(%rsp), %edx
	addl	%esi, %edx
	movl	%edx, %eax
	addq	$12, %rsp
	ret

Now we produce:

_foo:                                   ## @foo
	subq	$12, %rsp
	movl	%edi, 8(%rsp)
	movl	%esi, 4(%rsp)
	movl	%edx, (%rsp)
	movl	8(%rsp), %edx
	addl	4(%rsp), %edx    ## Folded load
	addl	(%rsp), %edx     ## Folded load
	movl	%edx, %eax
	addq	$12, %rsp
	ret

Fewer instructions and less register use = faster compiles.

llvm-svn: 113102
2010-09-05 02:18:34 +00:00
Bob Wilson 3626a8c136 Add a missing check when legalizing a vector extending load. This doesn't
solve the root problem, but it corrects the bug in the code I added to
support legalizing in the case where the non-extended type is also legal.

llvm-svn: 112997
2010-09-03 19:20:37 +00:00
Devang Patel 3bffd52d78 Detect undef value early and save unnecessary NodeMap query.
llvm-svn: 112864
2010-09-02 21:29:42 +00:00
Dan Gohman 3c9b5f394b Don't narrow the load and store in a load+twiddle+store sequence unless
there are clearly no stores between the load and the store. This fixes
this miscompile reported as PR7833.

This breaks the test/CodeGen/X86/narrow_op-2.ll optimization, which is
safe, but awkward to prove safe. Move it to X86's README.txt.

llvm-svn: 112861
2010-09-02 21:18:42 +00:00
Devang Patel 98d3edfe2a Tidy up.
llvm-svn: 112858
2010-09-02 21:02:27 +00:00
Devang Patel 86ec8b3a3f Reapply r112623. Included additional check for unused byval argument.
llvm-svn: 112659
2010-08-31 22:22:42 +00:00
Devang Patel 529f248eb4 Revert r112623. It is causing self host build failures.
llvm-svn: 112631
2010-08-31 19:41:03 +00:00
Devang Patel 8559932d36 Remember byval argument's frame index during argument lowering and use this info to emit debug info.
Fixes Radar 8367011.

llvm-svn: 112623
2010-08-31 18:50:09 +00:00
Devang Patel 417d72823a Offset is not always unsigned number.
llvm-svn: 112584
2010-08-31 06:12:08 +00:00
Bruno Cardoso Lopes d9ef4a1a24 zap unused method. x86 is the only user and already has a more powerfull version
llvm-svn: 112571
2010-08-31 02:36:20 +00:00
Bill Wendling f824489a1d Revert r112461. It was failing on PPC...
llvm-svn: 112463
2010-08-30 04:36:50 +00:00
Bill Wendling 938f299fa9 When adding a register, we should mark it as "def" if it can optionally define
said (physical) register.

llvm-svn: 112461
2010-08-30 01:36:05 +00:00
Chris Lattner 13ee795c42 remove unions from LLVM IR. They are severely buggy and not
being actively maintained, improved, or extended.

llvm-svn: 112356
2010-08-28 04:09:24 +00:00
Dan Gohman e06905d1f0 Completely disable tail calls when fast-isel is enabled, as fast-isel
doesn't currently support dealing with this.

llvm-svn: 112341
2010-08-28 00:51:03 +00:00
Dan Gohman 1e06dbf881 Trim a #include.
llvm-svn: 112340
2010-08-28 00:49:13 +00:00
Devang Patel f2855b147f Simplify.
llvm-svn: 112305
2010-08-27 22:25:51 +00:00
Devang Patel b12ff5999e Revert r112213. It is not needed.
llvm-svn: 112242
2010-08-26 23:35:15 +00:00
Devang Patel ea134f56b1 If node is not available then use FuncInfo.ValueMap to emit debug info for byval parameter.
llvm-svn: 112238
2010-08-26 22:53:27 +00:00
Devang Patel 42b4ac7ed3 Speculatively revert r112207.
llvm-svn: 112216
2010-08-26 20:33:42 +00:00
Devang Patel 977057f481 80 col.
llvm-svn: 112215
2010-08-26 20:32:32 +00:00
Devang Patel 384fa91deb Update DanglingDebugInfo so that it can be used to track llvm.dbg.declare also.
llvm-svn: 112213
2010-08-26 20:06:46 +00:00
Devang Patel ab596a637c Donot forget to resolve dangling debug info in a case where virtual register, used for a value, is initialized after a dbg intrinsic is seen.
llvm-svn: 112207
2010-08-26 18:36:14 +00:00
Chris Lattner af23e9a798 Add a hackaround for PR7993 which is causing failures on x86 builders that lack sse2.
llvm-svn: 112175
2010-08-26 06:57:07 +00:00
Chris Lattner eb2cc0ce0e implement SplitVecOp_CONCAT_VECTORS, fixing the included testcase with SSE1.
llvm-svn: 112171
2010-08-26 05:51:22 +00:00
Chris Lattner f6418b804e zap dead code.
llvm-svn: 112155
2010-08-26 02:57:35 +00:00
Chris Lattner 8df99b523e remove some llvmcontext arguments that are now dead post-refactoring.
llvm-svn: 112104
2010-08-25 23:00:45 +00:00
Chris Lattner 75ff053497 Change handling of illegal vector types to widen when possible instead of
expanding: e.g. <2 x float> -> <4 x float> instead of -> 2 floats.  This
affects two places in the code: handling cross block values and handling
function return and arguments.  Since vectors are already widened by 
legalizetypes, this gives us much better code and unblocks x86-64 abi
and SPU abi work.

For example, this (which is a silly example of a cross-block value):
define <4 x float> @test2(<4 x float> %A) nounwind {
 %B = shufflevector <4 x float> %A, <4 x float> undef, <2 x i32> <i32 0, i32 1>
 %C = fadd <2 x float> %B, %B
  br label %BB
BB:
 %D = fadd <2 x float> %C, %C
 %E = shufflevector <2 x float> %D, <2 x float> undef, <4 x i32> <i32 0, i32 1, i32 undef, i32 undef>
 ret <4 x float> %E
}

Now compiles into:

_test2:                                 ## @test2
## BB#0:
 addps %xmm0, %xmm0
 addps %xmm0, %xmm0
 ret

previously it compiled into:

_test2:                                 ## @test2
## BB#0:
 addps %xmm0, %xmm0
 pshufd $1, %xmm0, %xmm1
                                        ## kill: XMM0<def> XMM0<kill> XMM0<def>
 insertps $0, %xmm0, %xmm0
 insertps $16, %xmm1, %xmm0
 addps %xmm0, %xmm0
 ret

This implements rdar://8230384

llvm-svn: 112101
2010-08-25 22:49:25 +00:00
Devang Patel 32a72ab072 Fix comment.
llvm-svn: 112086
2010-08-25 20:41:24 +00:00
Devang Patel 3f53d6e56a Remove dead argument.
llvm-svn: 112085
2010-08-25 20:39:26 +00:00
Chris Lattner 05bcb488b5 split the vector case of getCopyFromParts out to its own function,
no functionality change.

llvm-svn: 111994
2010-08-24 23:20:40 +00:00
Chris Lattner 96a77ebd7c split the vector case out of getCopyToParts into its own function. No
functionality change.

llvm-svn: 111990
2010-08-24 23:10:06 +00:00
Chris Lattner 5b8967f8a2 tidy up, reduce indentation
llvm-svn: 111982
2010-08-24 22:43:11 +00:00
Chandler Carruth 191c4f73b2 Fix some GCC warnings by providing a virtual destructor in the base of a class
hierarchy with virtual methods and using llvm_unreachable to properly indicate
unreachable states which would otherwise leave variables uninitialized.

llvm-svn: 111803
2010-08-23 08:25:07 +00:00
Bob Wilson c56fef4eac If the target says that an extending load is not legal, regardless of whether
it involves specific floating-point types, legalize should expand an
extending load to a non-extending load followed by a separate extend operation.
For example, we currently expand SEXTLOAD to EXTLOAD+SIGN_EXTEND_INREG (and
assert that EXTLOAD should always be supported).  Now we can expand that to
LOAD+SIGN_EXTEND.  This is needed to allow vector SIGN_EXTEND and ZERO_EXTEND
to be used for NEON.

llvm-svn: 111586
2010-08-19 23:52:39 +00:00
Dale Johannesen 16f96445c3 Make fast scheduler handle asm clobbers correctly.
PR 7882.  Follows suggestion by Amaury Pouly, thanks.

llvm-svn: 111306
2010-08-17 22:17:24 +00:00
Eric Christopher 541f8012d9 Fix typo.
llvm-svn: 111223
2010-08-17 01:30:33 +00:00
Evan Cheng 23ef829096 Add missing null check reported by Amaury Pouly.
llvm-svn: 110649
2010-08-10 02:39:45 +00:00
Owen Anderson a7aed18624 Reapply r110396, with fixes to appease the Linux buildbot gods.
llvm-svn: 110460
2010-08-06 18:33:48 +00:00
Owen Anderson bda59bd247 Revert r110396 to fix buildbots.
llvm-svn: 110410
2010-08-06 00:23:35 +00:00
Owen Anderson 755aceb5d0 Don't use PassInfo* as a type identifier for passes. Instead, use the address of the static
ID member as the sole unique type identifier.  Clean up APIs related to this change.

llvm-svn: 110396
2010-08-05 23:42:04 +00:00
Dan Gohman 5cae103392 Eliminate unnecessary empty string literals.
llvm-svn: 110183
2010-08-04 01:39:08 +00:00
Oscar Fuentes 40b31ad3ee Prefix `next' iterator operation with `llvm::'.
Fixes potential ambiguity problems on VS 2010.

Patch by nobled!

llvm-svn: 110029
2010-08-02 06:00:15 +00:00
Eli Friedman 460ad41d6d PR7586: Make sure we don't claim that unknown bits are actually known in the
ISD::AND case of TargetLowering::SimplifyDemandedBits.

llvm-svn: 110019
2010-08-02 04:42:25 +00:00
Eli Friedman ffe64c06ef Fix for bug reported by Evzen Muller on llvm-commits: make sure to correctly
check the range of the constant when optimizing a comparison between a
constant and a sign_extend_inreg node.

llvm-svn: 109854
2010-07-30 06:44:31 +00:00
Nate Begeman 317b969ac5 Fix a crash in the dag combiner caused by ConstantFoldBIT_CONVERTofBUILD_VECTOR calling itself
recursively and returning a SCALAR_TO_VECTOR node, but assuming the input was always a BUILD_VECTOR.

llvm-svn: 109519
2010-07-27 18:02:18 +00:00
Bill Wendling 0ff1ef650b It's better to have the arrays, which would trigger the creation of stack
protectors, to be near the stack protectors on the stack. Accomplish this by
tagging the stack object with a predicate that indicates that it would trigger
this. In the prolog-epilog inserter, assign these objects to the stack after the
stack protector but before the other objects.

llvm-svn: 109481
2010-07-27 01:55:19 +00:00
Evan Cheng e6d6c5dd11 The "excess register pressure" returned by HighRegPressure() is not accurate enough to factor into scheduling priority. Eliminate it and add early exits to speed up scheduling.
llvm-svn: 109449
2010-07-26 21:49:07 +00:00
Dan Gohman 2810bacafb Handle Values with no value in getCopyFromRegs.
llvm-svn: 109415
2010-07-26 18:15:41 +00:00
Duncan Sands 136a6f0dbb Pacify gcc-4.5 which wrongly thinks that RExcess (passed as the Excess parameter)
may be used uninitialized in the callers of HighRegPressure.

llvm-svn: 109393
2010-07-26 07:54:17 +00:00
Evan Cheng 8ae3ecad2b Add comments.
llvm-svn: 109383
2010-07-25 18:59:43 +00:00
Bob Wilson 280ce9984e Fix crashes when scheduling a CopyToReg node -- getMachineOpcode asserts on
those.  Radar 8231572.

llvm-svn: 109367
2010-07-25 05:34:27 +00:00
Evan Cheng 37b740c4bf Add an ILP scheduler. This is a register pressure aware scheduler that's
appropriate for targets without detailed instruction iterineries.
The scheduler schedules for increased instruction level parallelism in
low register pressure situation; it schedules to reduce register pressure
when the register pressure becomes high.

On x86_64, this is a win for all tests in CFP2000. It also sped up 256.bzip2
by 16%.

llvm-svn: 109300
2010-07-24 00:39:05 +00:00
Evan Cheng df907f4594 - Allow target to specify when is register pressure "too high". In most cases,
it's too late to start backing off aggressive latency scheduling when most
  of the registers are in use so the threshold should be a bit tighter.
- Correctly handle live out's and extract_subreg etc.
- Enable register pressure aware scheduling by default for hybrid scheduler.
  For ARM, this is almost always a win on # of instructions. It's runtime
  neutral for most of the tests. But for some kernels with high register
  pressure it can be a huge win. e.g. 464.h264ref reduced number of spills by
  54 and sped up by 20%.

llvm-svn: 109279
2010-07-23 22:39:59 +00:00
Dan Gohman 55e244698a Use the proper type for shift counts. This fixes a bootstrap error.
llvm-svn: 109265
2010-07-23 21:08:12 +00:00
Dan Gohman 0818684a70 DAGCombine (shl (anyext x, c)) to (anyext (shl x, c)) if the high bits
are not demanded. This often allows the anyext to be folded away.

llvm-svn: 109242
2010-07-23 18:03:30 +00:00
Dan Gohman 2e00e3b12d Make SDNode::dump() print a newline at the end.
llvm-svn: 109234
2010-07-23 16:37:47 +00:00
Eric Christopher faf5c76114 80-col.
llvm-svn: 109205
2010-07-23 01:05:59 +00:00
Gabor Greif 59f9970ba5 keep in 80 cols
llvm-svn: 109122
2010-07-22 17:18:03 +00:00
Gabor Greif dde79d8f1a mass elimination of reliance on automatic iterator dereferencing
llvm-svn: 109103
2010-07-22 13:36:47 +00:00
Evan Cheng bf32e54bac Re-apply r109079 with fix.
llvm-svn: 109083
2010-07-22 06:24:48 +00:00
Owen Anderson 6c55cccf87 Revert r109079, which broke a lot of CodeGen tests.
llvm-svn: 109082
2010-07-22 06:01:28 +00:00
Evan Cheng bd81bff672 Initialize RegLimit only when register pressure is being tracked.
llvm-svn: 109079
2010-07-22 05:18:41 +00:00
Evan Cheng 285903853f More register pressure aware scheduling work.
llvm-svn: 109064
2010-07-21 23:53:58 +00:00
Evan Cheng a77f3d3b37 Teach bottom up pre-ra scheduler to track register pressure. Work in progress.
llvm-svn: 108991
2010-07-21 06:09:07 +00:00
Dan Gohman b5e918dc05 After a custom inserter, in a block which has constant instructions,
update the current basic block in addition to the current insert
position, so that they remain consistent. This fixes rdar://8204072.

llvm-svn: 108765
2010-07-19 22:48:56 +00:00
Evan Cheng 10f99a3490 ARM has to provide its own TargetLowering::findRepresentativeClass because its scalar floating point registers alias its vector registers.
llvm-svn: 108761
2010-07-19 22:15:08 +00:00
Evan Cheng 7a135510e3 Teach computeRegisterProperties() to compute "representative" register class for legal value types. A "representative" register class is the largest legal super-reg register class for a value type. e.g. On i386, GR32 is the rep register class for i8 / i16 / i32; on x86_64 it would be GR64.
This property will be used by the register pressure tracking instruction scheduler.

llvm-svn: 108735
2010-07-19 18:47:01 +00:00
Owen Anderson 9c271e2835 Remove r108639 now that it is handled by InstCombine instead.
llvm-svn: 108688
2010-07-19 08:10:24 +00:00
Owen Anderson f7f9c8a2f7 Add a DAGCombine xform to fold away redundant float->double->float conversions around sqrt instructions.
I am assured by people more knowledgeable than me that there are no rounding issues in eliminating this.

This fixed <rdar://problem/8197504>.

llvm-svn: 108639
2010-07-18 08:47:54 +00:00
Eric Christopher 0baaa9bcc1 Propagate alloca alignment information via variable size object frame
information.

No functional change yet.

llvm-svn: 108583
2010-07-17 00:28:22 +00:00
Dan Gohman 1e936277c3 Revert r108369, sorting llvm.dbg.declare information by source position,
since it doesn't work for front-ends which don't emit column information
(which includes llvm-gcc in its present configuration), and doesn't
work for clang for K&R style variables where the variables are declared
in a different order from the parameter list.

Instead, make a separate pass through the instructions to collect the
llvm.dbg.declare instructions in order. This ensures that the debug
information for variables is emitted in this order.

llvm-svn: 108538
2010-07-16 17:54:27 +00:00
Dan Gohman 103c4ebea5 Use the source-order scheduler instead of the "fast" scheduler at -O0,
because it's more likely to keep debug line information in its original
order.

llvm-svn: 108496
2010-07-16 02:01:19 +00:00
Dale Johannesen bfd4fd7bb7 The SelectionDAGBuilder's handling of debug info, on rare
occasions, caused code to be generated in a different order.
All cases I've seen involved float softening in the type
legalizer, and this could be perhaps be fixed there, but
it's better not to generate things differently in the first
place.  7797940 (6/29/2010..7/15/2010).

llvm-svn: 108484
2010-07-16 00:02:08 +00:00
Bill Wendling 4bda1c8e68 Revert. This isn't the correct way to go.
llvm-svn: 108478
2010-07-15 23:42:21 +00:00
Bill Wendling 973dc3b1d8 Handle code gen for the unreachable instruction if it's the only instruction in
the function. We'll just turn it into a "trap" instruction instead.

The problem with not handling this is that it might generate a prologue without
the equivalent epilogue to go with it:

$ cat t.ll
define void @foo() {
entry:
  unreachable
}
$ llc -o - t.ll -relocation-model=pic -disable-fp-elim -unwind-tables
        .section        __TEXT,__text,regular,pure_instructions
        .globl  _foo
        .align  4, 0x90
_foo:                                   ## @foo
Leh_func_begin0:
## BB#0:                                ## %entry
        pushq   %rbp
Ltmp0:
        movq    %rsp, %rbp
Ltmp1:
Leh_func_end0:
...

The unwind tables then have bad data in them causing all sorts of problems.

Fixes <rdar://problem/8096481>.

llvm-svn: 108473
2010-07-15 23:32:40 +00:00
Evan Cheng 55f0c6b9fc Split -enable-finite-only-fp-math to two options:
-enable-no-nans-fp-math and -enable-no-infs-fp-math. All of the current codegen fp math optimizations only care whether the fp arithmetics arguments and results can never be NaN.

llvm-svn: 108465
2010-07-15 22:07:12 +00:00
Devang Patel df09db62e2 Fix crash reported in PR7653.
llvm-svn: 108441
2010-07-15 18:45:27 +00:00
Eric Christopher 474e56a2bf 80-col.
llvm-svn: 108381
2010-07-14 23:41:32 +00:00
Dan Gohman c12a6731c5 Properly restore DebugLoc after leaving the local constant area.
llvm-svn: 108364
2010-07-14 22:01:31 +00:00
Dan Gohman 042523340b Delete fast-isel's trivial load optimization; it breaks debugging because
it can look past points where a debugger might modify user variables.

llvm-svn: 108336
2010-07-14 17:25:37 +00:00
Dan Gohman 1f471435f8 Don't propagate debug locations to instructions for materializing
constants, since they may not be emited near the other instructions
which get the same line, and this confuses debug info.

llvm-svn: 108302
2010-07-14 01:07:44 +00:00
Dale Johannesen caca5488dc In inline asm treat indirect 'X' constraint as 'm'.
This may not be right in all cases, but it's better
than asserting which it was doing before.  PR 7528.

llvm-svn: 108268
2010-07-13 20:17:05 +00:00
Rafael Espindola a18c5a0e5e Fix a typo and fit in 80 columns. Found by Bob Wilson.
llvm-svn: 108164
2010-07-12 18:11:17 +00:00
Duncan Sands 41b4a6b36a Convert some tab stops into spaces.
llvm-svn: 108130
2010-07-12 08:16:59 +00:00
Jakob Stoklund Olesen 51642aea77 Use COPY for fast-isel bitconvert, but don't create cross-class copies.
This doesn't change the behavior of SelectBitcast for X86.

llvm-svn: 108073
2010-07-11 05:16:54 +00:00
Rafael Espindola a76eccf815 Fix va_arg for doubles. With this patch VAARG nodes always contain the
correct alignment information, which simplifies ExpandRes_VAARG a bit.

The patch introduces a new alignment information to TargetLoweringInfo. This is
needed since the two natural candidates cannot be used:

* The 's' in target data: If this is set to the minimal alignment of any
  argument, getCallFrameTypeAlignment would return 4 for doubles on ARM for
  example.
* The getTransientStackAlignment method. It is possible for an architecture to
  have argument less aligned than what we maintain the stack pointer.

llvm-svn: 108072
2010-07-11 04:01:49 +00:00
Jakob Stoklund Olesen 7147ab9e78 Use COPY for extracting ImplicitDef'ed values from fast-isel instructions.
This assumes that the registers can be copied which is probably a safe
assumption.

llvm-svn: 108070
2010-07-11 03:31:05 +00:00
Jakob Stoklund Olesen 3bb1267431 Use COPY in FastISel everywhere it is safe and trivial.
The remaining copyRegToReg calls actually check the return value (shock!), so we
cannot trivially replace them with COPY instructions.

llvm-svn: 108069
2010-07-11 03:31:00 +00:00
Dan Gohman a64a323564 Fix a bug in the code which re-inserts DBG_VALUE nodes after scheduling;
if a block is split (by a custom inserter), the insert point may be in a
different block than it was originally. This fixes 32-bit llvm-gcc
bootstrap builds, and I haven't been able to reproduce it otherwise.

llvm-svn: 108060
2010-07-10 22:42:31 +00:00
Jakob Stoklund Olesen e50d30d586 Emit COPY instructions instead of using copyRegToReg in InstrEmitter,
ScheduleDAGEmit, TwoAddressLowering, and PHIElimination.

This switches the bulk of register copies to using COPY, but many less used
copyRegToReg calls remain.

llvm-svn: 108050
2010-07-10 19:08:25 +00:00
Dan Gohman fbdba81550 Insert IMPLICIT_DEF instructions at the current insert position, not
at the end of the block.

llvm-svn: 108045
2010-07-10 13:55:45 +00:00
Dan Gohman d7b5ce3312 Reapply bottom-up fast-isel, with several fixes for x86-32:
- Check getBytesToPopOnReturn().
 - Eschew ST0 and ST1 for return values.
 - Fix the PIC base register initialization so that it doesn't ever
   fail to end up the top of the entry block.

llvm-svn: 108039
2010-07-10 09:00:22 +00:00
Bill Wendling f831d86311 Clarify what mysterious check means.
llvm-svn: 108005
2010-07-09 19:44:12 +00:00
Bob Wilson 6586e9b203 --- Reverse-merging r107947 into '.':
U    utils/TableGen/FastISelEmitter.cpp
--- Reverse-merging r107943 into '.':
U    test/CodeGen/X86/fast-isel.ll
U    test/CodeGen/X86/fast-isel-loads.ll
U    include/llvm/Target/TargetLowering.h
U    include/llvm/Support/PassNameParser.h
U    include/llvm/CodeGen/FunctionLoweringInfo.h
U    include/llvm/CodeGen/CallingConvLower.h
U    include/llvm/CodeGen/FastISel.h
U    include/llvm/CodeGen/SelectionDAGISel.h
U    lib/CodeGen/LLVMTargetMachine.cpp
U    lib/CodeGen/CallingConvLower.cpp
U    lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
U    lib/CodeGen/SelectionDAG/FunctionLoweringInfo.cpp
U    lib/CodeGen/SelectionDAG/FastISel.cpp
U    lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
U    lib/CodeGen/SelectionDAG/ScheduleDAGSDNodes.cpp
U    lib/CodeGen/SelectionDAG/InstrEmitter.cpp
U    lib/CodeGen/SelectionDAG/TargetLowering.cpp
U    lib/Target/XCore/XCoreISelLowering.cpp
U    lib/Target/XCore/XCoreISelLowering.h
U    lib/Target/X86/X86ISelLowering.cpp
U    lib/Target/X86/X86FastISel.cpp
U    lib/Target/X86/X86ISelLowering.h

llvm-svn: 107987
2010-07-09 16:37:18 +00:00
Gabor Greif 52617fc462 cache result of operator*
llvm-svn: 107980
2010-07-09 16:08:33 +00:00
Dan Gohman 0b5aa1cdd3 Re-apply bottom-up fast-isel, with fixes. Be very careful to avoid emitting
a DBG_VALUE after a terminator, or emitting any instructions before an EH_LABEL.

llvm-svn: 107943
2010-07-09 00:39:23 +00:00
Bob Wilson 21eed476e8 Reenable DAG combining for vector shuffles. It looks like it was temporarily
disabled and then never turned back on again.  Adjust some tests, one because
this change avoids an unnecessary instruction, and the other to make it
continue testing what it was intended to test.

llvm-svn: 107941
2010-07-09 00:38:12 +00:00
Bill Wendling a992445ff2 Extension of r107506. Make sure that we don't mark a function as having a call
if the inline ASM doesn't need a stack frame.

llvm-svn: 107922
2010-07-08 22:38:02 +00:00
Jakob Stoklund Olesen 00264624a9 Convert EXTRACT_SUBREG to COPY when emitting machine instrs.
EXTRACT_SUBREG no longer appears as a machine instruction. Use COPY instead.

Add isCopy() checks in many places using isMoveInstr() and isExtractSubreg().
The isMoveInstr hook will be removed later.

llvm-svn: 107879
2010-07-08 16:40:22 +00:00
Benjamin Kramer 0ae3f08c0d Merge the duplicated iabs optimization in DAGCombiner and let it detected a few more idioms.
llvm-svn: 107868
2010-07-08 12:09:56 +00:00
Dan Gohman e75704369d Revert 107840 107839 107813 107804 107800 107797 107791.
Debug info intrinsics win for now.

llvm-svn: 107850
2010-07-08 01:00:56 +00:00
Dan Gohman eb9164dc50 Don't forward-declare registers for static allocas, which we'll
prefer to materialize as local constants. This fixes the clang
bootstrap abort.

llvm-svn: 107840
2010-07-07 23:52:58 +00:00
Dan Gohman 1adc499dda Fix -fast-isel-abort to check the right instruction.
llvm-svn: 107839
2010-07-07 23:47:25 +00:00
Evan Cheng 1c349f18f8 Move getExtLoad() and (some) getLoad() DebugLoc argument after EVT argument for consistency sake.
llvm-svn: 107820
2010-07-07 22:15:37 +00:00
Dan Gohman 25d5c1b4f8 Not all custom inserters create new basic blocks. If the inserter
didn't create a new block, don't reset the insert position.

llvm-svn: 107813
2010-07-07 21:18:22 +00:00
Dan Gohman e7ccc51cc1 Implement bottom-up fast-isel. This has the advantage of not requiring
a separate DCE pass over MachineInstrs.

llvm-svn: 107804
2010-07-07 19:20:32 +00:00
Dan Gohman 2d4d01d0de Add X86FastISel support for return statements. This entails refactoring
a bunch of stuff, to allow the target-independent calling convention
logic to be employed.

llvm-svn: 107800
2010-07-07 18:32:53 +00:00
Dan Gohman b792f844ad Update the insert position after scheduling, which may change the
position when emitting multiple blocks when executing a custom
inserter.

llvm-svn: 107797
2010-07-07 18:22:13 +00:00
Devang Patel 637ee5f149 Update comment.
llvm-svn: 107796
2010-07-07 18:18:18 +00:00
Dan Gohman ffe64b1ee5 Give FunctionLoweringInfo an MBB member, avoiding the need to pass it
around everywhere, and also give it an InsertPt member, to enable isel
to operate at an arbitrary position within a block, rather than just
appending to a block.

llvm-svn: 107791
2010-07-07 16:47:08 +00:00
Dan Gohman 87fb4e8fcd Simplify FastISel's constructor by giving it a FunctionLoweringInfo
instance, rather than pointers to all of FunctionLoweringInfo's
members.

This eliminates an NDEBUG ABI sensitivity.

llvm-svn: 107789
2010-07-07 16:29:44 +00:00
Dan Gohman e784616fbb Move FunctionLoweringInfo.h out into include/llvm/CodeGen. This will
allow target-specific fast-isel code to make use of it directly.

llvm-svn: 107787
2010-07-07 16:01:37 +00:00
Dan Gohman fe7532a308 Split the SDValue out of OutputArg so that SelectionDAG-independent
code can do calling-convention queries. This obviates OutputArgReg.

llvm-svn: 107786
2010-07-07 15:54:55 +00:00
Dan Gohman 498e5f899d Move CallingConvLower.cpp out of the SelectionDAG directory.
llvm-svn: 107781
2010-07-07 15:15:27 +00:00
Jim Grosbach dc0a0659be By default, the eh.sjlj.setjmp/longjmp intrinsics should just do nothing rather
than assuming a target will custom lower them. Targets which do so should
exlicitly mark them as having custom lowerings. PR7454.

llvm-svn: 107734
2010-07-06 23:44:52 +00:00
Dan Gohman ee0cb70381 CanLowerReturn doesn't need a SelectionDAG; it just needs an LLVMContext.
SelectBasicBlock doesn't needs its BasicBlock argument.

llvm-svn: 107712
2010-07-06 22:19:37 +00:00
Devang Patel a3ca21b228 Propagate debug loc.
llvm-svn: 107710
2010-07-06 22:08:15 +00:00
Dan Gohman 3439629239 Reapply r107655 with fixes; insert the pseudo instruction into
the block before calling the expansion hook. And don't
put EFLAGS in a mbb's live-in list twice.

llvm-svn: 107691
2010-07-06 20:24:04 +00:00
Dan Gohman 4e49b59dad Add versions of OutputArgReg, AnalyzeReturn, and AnalyzeCallOperands
which do not depend on SelectionDAG.

llvm-svn: 107666
2010-07-06 15:39:54 +00:00
Chris Lattner c4a7073db3 more tidying.
llvm-svn: 107615
2010-07-05 05:53:14 +00:00
Chris Lattner 2c0315a0f3 random tidying
llvm-svn: 107612
2010-07-05 05:36:21 +00:00
Evan Cheng f3aeb2c22c Infer alignments of fixed frame objects when they are constructed. This ensures remat'ed loads from fixed slots have the right alignments.
llvm-svn: 107591
2010-07-04 18:52:05 +00:00
Bill Wendling f844642350 Proper indentation.
llvm-svn: 107581
2010-07-04 08:58:43 +00:00
Dale Johannesen 4d887f7ca7 Propagate the AlignStack bit in InlineAsm's to the
PrologEpilog code, and use it to determine whether
the asm forces stack alignment or not.  gcc consistently
does not do this for GCC-style asms; Apple gcc inconsistently
sometimes does it for asm blocks.  There is no
convenient place to put a bit in either the SDNode or
the MachineInstr form, so I've added an extra operand
to each; unlovely, but it does allow for expansion for
more bits, should we need it.  PR 5125.  Some
existing testcases are affected.
The operand lists of the SDNode and MachineInstr forms
are indexed with awesome mnemonics, like "2"; I may
fix this someday, but not now.  I'm not making it any
worse.  If anyone is inspired I think you can find all
the right places from this patch.

llvm-svn: 107506
2010-07-02 20:16:09 +00:00
Jim Grosbach 9b7755fbc6 80-column and trailing whitespace cleanup.
llvm-svn: 107490
2010-07-02 17:41:59 +00:00
Jim Grosbach 64a4f3f062 grammar tweaks
llvm-svn: 107489
2010-07-02 17:38:34 +00:00
Dan Gohman 93f5920914 Rename CreateReg to CreateRegs, and MakeReg to CreateReg.
llvm-svn: 107451
2010-07-02 00:10:16 +00:00
Dan Gohman d2965c10a1 Temporarily disable on-demand fast-isel.
llvm-svn: 107393
2010-07-01 12:15:30 +00:00
Dan Gohman 42b7ee15f5 Use FuncInfo's isExportedInst accessor method instead of
doing the work manually.

llvm-svn: 107384
2010-07-01 03:57:05 +00:00
Dan Gohman 85e02e9340 Rename CreateRegForValue to CreateReg, and change its argument
from a Value to a Type, because it doesn't actually care about
the Value.

llvm-svn: 107383
2010-07-01 03:55:39 +00:00
Dan Gohman aef3d140b7 Teach fast-isel to avoid loading a value from memory when it's already
available in a register. This is pretty primitive, but it reduces the
number of instructions in common testcases by 4%.

llvm-svn: 107380
2010-07-01 03:49:38 +00:00
Dan Gohman 722f5fc567 Enable on-demand fast-isel.
llvm-svn: 107377
2010-07-01 02:58:57 +00:00
Dan Gohman d432223163 Reapply r106422, splitting the code for materializing a value out of
SelectionDAGBuilder::getValue into a helper function, with fixes to
use DenseMaps safely.

llvm-svn: 107371
2010-07-01 01:59:43 +00:00
Dan Gohman 9576645a84 Don't use operator[] here, because it's not desirable to insert a default
value if the search fails.

llvm-svn: 107368
2010-07-01 01:33:21 +00:00
Jim Grosbach caf9b3ab7d grammar tweak in comment.
llvm-svn: 107321
2010-06-30 21:27:56 +00:00
Duncan Sands 945a347478 Remove an unused variable. The call to getRoot has side-effects, so
this could break something (but doesn't seem to).

llvm-svn: 107295
2010-06-30 17:22:28 +00:00
Gabor Greif 647d9c9797 use ArgOperand API
llvm-svn: 107282
2010-06-30 13:45:50 +00:00
Gabor Greif f69acfe133 use ArgOperand API
llvm-svn: 107279
2010-06-30 12:55:46 +00:00
Rafael Espindola 38a7d7cbc3 Add a VT argument to getMinimalPhysRegClass and replace the copy related uses
of getPhysicalRegisterRegClass with it.

If we want to make a copy (or estimate its cost), it is better to use the
smallest class as more efficient operations might be possible.

llvm-svn: 107140
2010-06-29 14:02:34 +00:00
Duncan Sands 6d28e73acc Remove initialized but otherwise unused variables.
llvm-svn: 107127
2010-06-29 11:22:26 +00:00
Bob Wilson 269a89fd3a Unlike other targets, ARM now uses BUILD_VECTORs post-legalization so they
can't be changed arbitrarily by the DAGCombiner without checking if it is
running after legalization.

llvm-svn: 107097
2010-06-28 23:40:25 +00:00
Dale Johannesen 17feb07c53 In asm's, output operands with matching input constraints
have to be registers, per gcc documentation.  This affects
the logic for determining what "g" should lower to.  PR 7393.
A couple of existing testcases are affected.

llvm-svn: 107079
2010-06-28 22:09:45 +00:00
Rafael Espindola 2041abd958 When splitting a VAARG, remember its alignment.
This produces terrible but correct code.

llvm-svn: 106952
2010-06-26 18:22:20 +00:00
Evan Cheng 02b184de5b Change if-conversion block size limit checks to add some flexibility.
llvm-svn: 106901
2010-06-25 22:42:03 +00:00
Dale Johannesen ce97d55ad9 The hasMemory argument is irrelevant to how the argument
for an "i" constraint should get lowered; PR 6309.  While
this argument was passed around a lot, this is the only
place it was used, so it goes away from a lot of other
places.

llvm-svn: 106893
2010-06-25 21:55:36 +00:00
Duncan Sands 2dc70bea54 Remove variables which are assigned to but for which the value
is not used.  Spotted by gcc-4.6.

llvm-svn: 106854
2010-06-25 14:48:39 +00:00
Gabor Greif eba0be7dc9 use ArgOperand API
llvm-svn: 106836
2010-06-25 09:38:13 +00:00
Gabor Greif e4eed709d4 use ArgOperand API
llvm-svn: 106828
2010-06-25 08:24:59 +00:00
Gabor Greif f6207e0a80 prune an include
llvm-svn: 106827
2010-06-25 08:16:50 +00:00
Bill Wendling 2d3c490026 It's possible that a flag is added to the SDNode that points back to the
original SDNode. This is badness. Also, this function allows one SDNode to point
multiple flags to another SDNode. Badness as well.

llvm-svn: 106793
2010-06-24 22:00:37 +00:00
Dan Gohman 8a84cd57ae Simplify this code; switch lowering shouldn't produce cases
which trivially fold away.

llvm-svn: 106765
2010-06-24 17:08:31 +00:00
Dan Gohman 463f26b4be Eliminate the other half of the BRCOND optimization, and update
as many tests as possible.

llvm-svn: 106749
2010-06-24 15:24:03 +00:00
Dan Gohman df6b33e778 Eliminate the first have of the optimization which eliminates BRCOND
when the condition is constant. This optimization shouldn't be
necessary, because codegen shouldn't be able to find dead control
paths that the IR-level optimizer can't find. And it's undesirable,
because it encourages bugpoint to leave "br i1 false" branches
in its output. And it wasn't updating the CFG.

I updated all the tests I could, but some tests are too reduced
and I wasn't able to meaningfully preserve them.

llvm-svn: 106748
2010-06-24 15:04:11 +00:00
Dan Gohman 600f62b3ba Reapply r106634, now that the bug it exposed is fixed.
llvm-svn: 106746
2010-06-24 14:30:44 +00:00
Dan Gohman 0695e09b09 Optimize the "bit test" code path for switch lowering in the
case where the bit mask has exactly one bit.

llvm-svn: 106716
2010-06-24 02:06:24 +00:00
Bill Wendling a136521a17 MorphNodeTo doesn't preserve the memory operands. Because we're morphing a node
into the same node, but with different non-memory operands, we need to replace
the memory operands after it's finished morphing.

llvm-svn: 106643
2010-06-23 18:16:24 +00:00
Daniel Dunbar 4df321b7ad Revert r106263, "Fold the ShrinkDemandedOps pass into the regular DAGCombiner pass,"... it was causing both 'file' (with clang) and 176.gcc (with llvm-gcc) to be miscompiled.
llvm-svn: 106634
2010-06-23 17:09:26 +00:00
Jim Grosbach b58c08b0ba Some targets don't require the fencing MEMBARRIER instructions surrounding
atomic intrinsics, either because the use locking instructions for the
atomics, or because they perform the locking directly. Add support in the
DAG combiner to fold away the fences.

llvm-svn: 106630
2010-06-23 16:07:42 +00:00
Dan Gohman dd41bba517 Use A.append(...) instead of A.insert(A.end(), ...) when A is a
SmallVector, and other SmallVector simplifications.

llvm-svn: 106452
2010-06-21 19:47:52 +00:00
Dan Gohman bbc29ea821 Revert r106422, which is breaking the non-fast-isel path.
llvm-svn: 106423
2010-06-21 16:02:28 +00:00
Dan Gohman f64fdd69d0 More changes for non-top-down fast-isel.
Split the code for materializing a value out of
SelectionDAGBuilder::getValue into a helper function, so that it can
be used in other ways. Add a new getNonRegisterValue function which
uses it, for use in code which doesn't want a CopyFromReg even
when FuncMap.ValueMap already has an entry for it.

llvm-svn: 106422
2010-06-21 15:13:54 +00:00
Dan Gohman f91aff5f13 Do one lookup instead of two.
llvm-svn: 106415
2010-06-21 14:21:47 +00:00
Dan Gohman 7c58cf75fa Generalize this to look in the regular ValueMap in addition to
the LocalValueMap, to make it more flexible when fast-isel isn't
proceding straight top-down.

llvm-svn: 106414
2010-06-21 14:17:46 +00:00
Dan Gohman 8693650422 Teach regular and fast isel to set dead flags on unused implicit defs
on calls and similar instructions.

llvm-svn: 106353
2010-06-18 23:28:01 +00:00
Jim Grosbach a57c2885cf back-end libcall handling for ATOMIC_SWAP (__sync_lock_test_and_set)
llvm-svn: 106342
2010-06-18 23:03:10 +00:00
Evan Cheng f5d62535a5 Fix cross initialization compilation error.
llvm-svn: 106324
2010-06-18 22:01:37 +00:00
Jim Grosbach d64dfc1568 Add Expand-to-libcall support for additional atomics. This covers the usual
entries used by llvm-gcc. *_[U]MIN and such can be added later if needed.

This enables the front ends to simplify handling of the atomic intrinsics by
removing the target-specific decision about which targets can handle the
intrinsics.

llvm-svn: 106321
2010-06-18 21:43:38 +00:00
Dan Gohman 7edb39cc6b Minor code simplifications.
llvm-svn: 106286
2010-06-18 16:00:29 +00:00
Dan Gohman 6e681a5fbe Give NamedRegionTimer an Enabled flag, allowing all its clients to
switch from this:

  if (TimePassesIsEnabled) {
    NamedRegionTimer T(Name, GroupName);
    do_something();
  } else {
    do_something(); // duplicate the code, this time without a timer!
  }

to this:

  {
    NamedRegionTimer T(Name, GroupName, TimePassesIsEnabled);
    do_something();
  }

llvm-svn: 106285
2010-06-18 15:56:31 +00:00
Dan Gohman 96ca25eba5 Don't replace the old Ordering object with a new one; just clear()
the old one.

llvm-svn: 106284
2010-06-18 15:40:58 +00:00
Dan Gohman a4f46b3ef8 Don't call clear() on DbgInfo when it's going to be deleted anyway.
Don't replace the old DbgInfo with a new one when clear() on the
old one is sufficient.

llvm-svn: 106283
2010-06-18 15:36:18 +00:00
Dan Gohman 92c11acdb8 Change UpdateNodeOperands' operand and return value from SDValue to
SDNode *, since it doesn't care about the ResNo value.

llvm-svn: 106282
2010-06-18 15:30:29 +00:00
Dan Gohman f1d8304fe3 Eliminate unnecessary uses of getZExtValue().
llvm-svn: 106279
2010-06-18 14:22:04 +00:00
Dan Gohman 35b6f9a929 isValueValidForType can be a static member function.
llvm-svn: 106278
2010-06-18 14:01:07 +00:00
Dan Gohman b92156d5e4 Fold the ShrinkDemandedOps pass into the regular DAGCombiner pass,
which is faster, simpler, and less surprising.

llvm-svn: 106263
2010-06-18 01:05:21 +00:00
Dan Gohman 0883789ec4 Handle ext(ext(x)) -> ext(x) immediately, since it's simple.
llvm-svn: 106256
2010-06-18 00:08:30 +00:00
Stuart Hastings 0125b6410a Add a DebugLoc parameter to TargetInstrInfo::InsertBranch(). This
addresses a longstanding deficiency noted in many FIXMEs scattered
across all the targets.

This effectively moves the problem up one level, replacing eleven
FIXMEs in the targets with eight FIXMEs in CodeGen, plus one path
through FastISel where we actually supply a DebugLoc, fixing Radar
7421831.

llvm-svn: 106243
2010-06-17 22:43:56 +00:00
Jim Grosbach 0ed5b460dc add missing break. inconsequential as the code shouldn't be reached, but
for correctness' sake, it should be there.

llvm-svn: 106229
2010-06-17 17:58:54 +00:00
Jim Grosbach 3aeae8aeeb Add entries for Expanding atomic intrinsics to libcalls. Just a placeholder
for the moment. The implementation of the libcall will follow.

Currently, the llvm-gcc knows when the intrinsics can be correctly handled by
the back end and only generates them in those cases, issuing libcalls directly
otherwise. That's too much coupling. The intrinsics should always be
generated and the back end decide how to handle them, be it with a libcall,
inline code, or whatever. This patch is a step in that direction.

rdar://8097623

llvm-svn: 106227
2010-06-17 17:50:54 +00:00
Jim Grosbach ba451e80dc ISD::MEMBARRIER should lower to a libcall (__sync_synchronize) if the target
sets the legalize action to Expand.

llvm-svn: 106203
2010-06-17 02:00:53 +00:00
Mon P Wang 7a84689cc5 Fixed vector widening of binary instructions that can trap. Patch by Visa Putkinen!
llvm-svn: 106038
2010-06-15 20:29:05 +00:00
Evan Cheng 38f6560461 Code refactoring, no functionality changes.
llvm-svn: 105775
2010-06-10 02:09:31 +00:00
Jakob Stoklund Olesen 8bc5eca331 Mark physregs defined by inline asm as implicit.
This is a bit of a hack to make inline asm look more like call instructions.
It would be better to produce correct dead flags during isel.

llvm-svn: 105749
2010-06-09 20:05:00 +00:00
Jakob Stoklund Olesen a13b1c29b0 Add argument name comments.
llvm-svn: 105665
2010-06-09 00:40:31 +00:00
Mon P Wang 622cdd2297 Fixed a bug during widening where we would avoid legalizing a node. When we
replace an OpA with a widened OpB, it is possible to get new uses of OpA due to CSE
when recursively updating nodes.  Since OpA has been processed, the new uses are
not examined again.  The patch checks if this occurred and it it did, updates the
new uses of OpA to use OpB.

llvm-svn: 105453
2010-06-04 01:20:10 +00:00
Dan Gohman d83e3e7750 Fix SimplifyDemandedBits' AssertZext logic to demand all the bits. It
needs to demand the high bits because it's asserting that they're zero.

llvm-svn: 105406
2010-06-03 20:21:33 +00:00
Eli Friedman dbbbf73c96 Implement expansion in type legalization for add/sub with overflow. The
expansion is the same as that used by LegalizeDAG.

The resulting code sucks in terms of performance/codesize on x86-32 for a
64-bit operation; I haven't looked into whether different expansions might be
better in general.

llvm-svn: 105378
2010-06-03 03:49:50 +00:00