Commit Graph

23524 Commits

Author SHA1 Message Date
Filipe Cabecinhas
c657a09ea6 Revert "YAMLIO: Encode ambiguous hex strings explicitly"
This reverts commit r205839.

It broke several tests in lld.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205857 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 14:35:17 +00:00
Arnold Schwaighofer
b0ee2374ce SLPVectorizer: Only vectorize intrinsics whose operands are widened equally
The vectorizer only knows how to vectorize intrinics by widening all operands by
the same factor.

Patch by Tyler Nowicki!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205855 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 14:20:47 +00:00
Elena Demikhovsky
0d5d656524 AVX-512: insert element to mask vector; store i1 data
Implemented INSERT_VECTOR_ELT operation for v16i1 and v8i1 vectors;
Implemented "store" for i1 type


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205850 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 12:37:50 +00:00
Daniel Sanders
e777fb4725 Re-commit: [mips] abs.[ds], and neg.[ds] should be allowed regardless of -enable-no-nans-fp-math
Summary:
They behave in accordance with the Has2008 and ABS2008 configuration bits of the processor which are used to select between the 1985 and 2008 versions of IEEE 754. In 1985 mode, these instructions are arithmetic (i.e. they raise invalid operation exceptions when given NaN), in 2008 mode they are non-arithmetic (i.e. they are copies).

nmadd.[ds], and nmsub.[ds] are still subject to -enable-no-nans-fp-math because the ISA spec does not explicitly state that they obey Has2008 and ABS2008.

Fixed the issue with the previous version of this patch (r205628). A pre-existing 'let Predicate =' statement was removing some predicates that were necessary for FP64 to behave correctly.

Reviewers: matheusalmeida

Reviewed By: matheusalmeida

Differential Revision: http://llvm-reviews.chandlerc.com/D3274



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205844 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 09:56:43 +00:00
David Majnemer
7184f49f40 YAMLIO: Encode ambiguous hex strings explicitly
YAMLIO would turn a BinaryRef into the string 0000000004000000.
However, the leading zero causes parsers to interpret it as being an
octal number instead of a hexadecimal one.

Instead, escape such strings as needed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205839 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 07:56:27 +00:00
Matt Arsenault
d4786ed1de R600/SI: Match not instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205837 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 07:16:16 +00:00
Tim Northover
87a79507fa ARM64: scalarize v1i64 mul operation
This is the second part of fixing PR19367.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205836 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 07:07:02 +00:00
Tim Northover
7db3c63bb2 ARM64: add pattern for <1 x i64> custom not node.
This should fix PR19367.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205835 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-09 06:55:39 +00:00
David Majnemer
e4d89ec8de WinCOFF: Emit common symbols as specified in the COFF spec
Summary:
Local common symbols were properly inserted into the .bss section.
However, putting external common symbols in the .bss section would give
them a strong definition.

Instead, encode them as undefined, external symbols who's symbol value
is equivalent to their size.

Reviewers: Bigcheese, rafael, rnk

CC: llvm-commits

Differential Revision: http://reviews.llvm.org/D3324

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205811 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 22:33:40 +00:00
Sebastian Pop
d541e6e6ea in findGCD of multiply expr return the gcd
we used to return 1 instead of the gcd

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205800 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 21:21:05 +00:00
Juergen Ributzka
c6a7502a80 [Constant Hoisting][ARM64] Enable constant hoisting for ARM64.
This implements the target-hooks for ARM64 to enable constant hoisting.

This fixes <rdar://problem/14774662> and <rdar://problem/16381500>.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205791 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 20:39:59 +00:00
Kevin Enderby
9143956488 Fix the ARM VLD3 (single 3-element structure to all lanes)
size 16 double-spaced registers instruction printing.

This:
	vld3.16 {d0[], d2[], d4[]}, [r4]!

was being printed as:

	vld3.16	{d0[], d1[], d2[]}, [r4]!

rdar://16531387


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205779 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 18:00:52 +00:00
Diego Novillo
35d647b6f3 Add -pass-remarks flag to 'opt'.
Summary:
This adds support in 'opt' to filter pass remarks emitted by
optimization passes. A new flag -pass-remarks specifies which
passes should emit a diagnostic when LLVMContext::emitOptimizationRemark
is invoked.

This will allow the front end to simply pass along the regular
expression from its own -Rpass flag when launching the backend.

Depends on D3227.

Reviewers: qcolombet

CC: llvm-commits

Differential Revision: http://llvm-reviews.chandlerc.com/D3291

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205775 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 16:42:38 +00:00
NAKAMURA Takumi
60db02b6fe X86MCAsmInfoGNUCOFF: Set PointerSize as 8 for targeting x64. It caused DW_LNE_set_address was misemitted on x64.
FIXME: I haven't investigate whether CalleeSaveStackSlotSize should be 8.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205772 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 15:28:50 +00:00
Tim Northover
362090adf5 ARM64: fix fmsub patterns which assumed accum operand was first
Confusingly, the NEON fmla instructions put the accumulator first but the
scalar versions put it at the end (like the fma lib function & LLVM's
intrinsic).

This should fix PR19345, assuming there's only one issue.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205758 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 12:23:51 +00:00
Elena Demikhovsky
dbcb670605 AVX-512: Added fp_to_uint and uint_to_fp patterns.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205754 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-08 07:24:02 +00:00
David Majnemer
de6256c938 obj2yaml: Use the correct relocation type for different machine types
The IO normalizer would essentially lump I386 and AMD64 relocations
together.  Relocation types with the same numeric value would then get
mapped in appropriately.

For example:
IMAGE_REL_AMD64_ADDR64 and IMAGE_REL_I386_DIR16 both have a numeric
value of one.  We would see IMAGE_REL_I386_DIR16 in obj2yaml conversions
of object files with a machine type of IMAGE_FILE_MACHINE_AMD64.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205746 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 23:12:20 +00:00
Reed Kotler
bb0572a5d1 Reverting commit r205628 due to mips64 issues.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205741 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 22:11:40 +00:00
Tom Stellard
1d8c7eb225 R600/SI: Handle INSERT_SUBREG in SIFixSGPRCopies
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205732 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 19:45:45 +00:00
Tom Stellard
5c9bb7119a R600: Match 24-bit arithmetic patterns in a Target DAGCombine
Moving these patterns from TableGen files to PerformDAGCombine()
should allow us to generate better code by eliminating unnecessary
shifts and extensions earlier.

This also fixes a bug where the MAD pattern was calling
SimplifyDemandedBits with a 24-bit mask on the first operand
even when the full pattern wasn't being matched.  This occasionally
resulted in some instructions being incorrectly deleted from the
program.

v2:
  - Fix bug with 64-bit mul

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205731 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 19:45:41 +00:00
Eric Christopher
dd455fd120 Revert the last couple of patches here and go back to something
that at least failed reliably.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205711 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 13:36:26 +00:00
Eric Christopher
9a764dfa92 Handle vlas during inline cost computation if they'll be turned
into a constant size alloca by inlining.

Ran a run over the testsuite, no results out of the noise, fixes
the testcase in the PR.

PR19115.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205710 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 13:36:21 +00:00
Eric Christopher
531bece9f5 XFAIL this completely at the moment:
cygwin has llvm-dwarfdump problems and isn't paying attention to the
specific xfail there.

s390x isn't matching for an unknown reason.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205708 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 13:10:27 +00:00
Eric Christopher
4639d0c904 Make test run on most platforms and only fail on cygwin/mingw while
it's being investigated for those.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205704 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-07 12:32:12 +00:00
NAKAMURA Takumi
2e858fcaad Quick fix: Triple::isOSMSVCRT() should be false for targeting cygwin.
It affected callee's stack pop in x86. It is one of devergences between cygwin and mingw since mingw-gcc-4.6.

Added testcases to llvm/test/CodeGen/X86/win32_sret.ll for cygwin.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205688 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-06 10:01:23 +00:00
David Blaikie
1c41705d34 DebugInfo: Support namespace aliases as DW_TAG_imported_declaration instead of DW_TAG_imported_module
I really should read the spec more often (and test GCC more often too).
I just assumed that namespace aliases would be the same as using
directives, except with a name. But apparently that's not how the DWARF
standards suggests they be implemented. DWARF4 provides an example and
other non-normative text suggesting that namespace aliases be
implemented by named imported declarations intsead of named imported
modules.

So be it.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205685 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-06 06:29:01 +00:00
Saleem Abdulrasool
fa254cb46c AsmParser: add a warning for compatibility parsing
This adds a warning when linker_private or linker_private_weak is provided and
we handle it in a compatible manner.

Suggested by Chris Lattner!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205681 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-05 22:42:53 +00:00
Saleem Abdulrasool
2a65dd3101 ARM: consolidate MachO checks for ARM asm parser
This consolidates the duplicated MachO checks in the directive parsing for
various directives that are unsupported for Mach-O.  The error message change is
unimportant as this restores the behaviour to that prior to the addition of the
new directive handling.  Furthermore, use a more direct check for MachO
targeting rather than an indirect feature check of the assembler.

Also simplify the test execution command to avoid temporary files.  Further more,
perform the check in both object and assembly emission.

Whether all non-applicable directives are handled is another question.  .fnstart
is marked as being unsupported, however, the complementary .fnend is not.  The
additional unwinding directives are also still honoured.  This change does not
change that, though, it would be good to validate and mark them as being
unsupported if they are unsupported for the MachO emission.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205678 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-05 22:09:51 +00:00
Saleem Abdulrasool
48ee81c679 AsmParser: restore LLVM IR compatibility for linker_private{,_weak}
This restores the linker_private and linker_private_weak lexemes to permit
translation of the deprecated lexmes.  The behaviour is identical to the bitcode
handling: linker_private and linker_private_weak are handled as if private had
been specified.  This enables compatibility with IR generated by LLVM 3.4.

Reported on IRC by ki9a!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205675 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-05 20:51:58 +00:00
Hal Finkel
e6a5b33e6e [PowerPC] Adjust load/store costs in PPCTTI
This provides more realistic costs for the insert/extractelement instructions
(which are load/store pairs), accounts for the cheap unaligned Altivec load
sequence, and for unaligned VSX load/stores.

Bad news:
MultiSource/Applications/sgefa/sgefa - 35% slowdown (this will require more investigation)
SingleSource/Benchmarks/McGill/queens - 20% slowdown (we no longer vectorize this, but it was a constant store that was scalarized)
MultiSource/Benchmarks/FreeBench/pcompress2/pcompress2 - 2% slowdown

Good news:
SingleSource/Benchmarks/Shootout/ary3 - 54% speedup
SingleSource/Benchmarks/Shootout-C++/ary - 40% speedup
MultiSource/Benchmarks/Ptrdist/ks/ks - 35% speedup
MultiSource/Benchmarks/FreeBench/neural/neural - 30% speedup
MultiSource/Benchmarks/TSVC/Symbolics-flt/Symbolics-flt - 20% speedup

Unfortunately, estimating the costs of the stack-based scalarization sequences
is hard, and adjusting these costs is like a game of whac-a-mole :( I'll
revisit this again after we have better codegen for vector extloads and
truncstores and unaligned load/stores.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205658 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 23:51:18 +00:00
Juergen Ributzka
7330dcb873 Update the test to use FileCheck.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205647 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 19:57:01 +00:00
Kai Nacke
a1329ecb8e [mips] Add Octeon cnMips instructions seqi/snei and v3mulu/vmm0/vmulu.
This patch adds the Octeon cnMips instructions seqi/snei and v3mulu/vmm0/vmulu.
It is only for the assembler. Test case is included.

Reviewed by: Daniel.Sanders@imgtec.com

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205631 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 16:21:59 +00:00
Hal Finkel
b12c642bbf [PowerPC] Add a full condition code register to make the "cc" clobber work
gcc inline asm supports specifying "cc" as a clobber of all condition
registers. Add just enough modeling of the full register to make this work.
Fixed PR19326.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205630 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 15:15:57 +00:00
Daniel Sanders
dc404fff12 [mips] abs.[ds], and neg.[ds] should be allowed regardless of -enable-no-nans-fp-math
Summary:
They behave in accordance with the Has2008 and ABS2008 configuration bits of the
processor which are used to select between the 1985 and 2008 versions of IEEE
754. In 1985 mode, these instructions are arithmetic (i.e. they raise invalid
operation exceptions when given NaN), in 2008 mode they are non-arithmetic
(i.e. they are copies).

nmadd.[ds], and nmsub.[ds] are still subject to -enable-no-nans-fp-math because
the ISA spec does not explicitly state that they obey Has2008 and ABS2008.

Reviewers: matheusalmeida

Reviewed By: matheusalmeida

Differential Revision: http://llvm-reviews.chandlerc.com/D3274

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205628 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 14:52:54 +00:00
Tim Northover
659e09e372 DAGLegalize: add last-ditch type-legalization for VSELECT.
When LLVM sees something like (v1iN (vselect v1i1, v1iN, v1iN)) it can
decide that the result is OK (v1i64 is legal on AArch64, for example)
but it still need scalarising because of that v1i1. There was no code
to do this though.

AArch64 and ARM64 have DAG combines to produce efficient code and
prevent that occuring in *most* such situations, but there are edge
cases that they miss. This adds a legalization to cope with that.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205626 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 14:49:30 +00:00
Tim Northover
4a4d62bfb9 ARM64: handle v1i1 types arising from setcc properly.
There were several overlapping problems here, and this solution is
closely inspired by the one adopted in AArch64 in r201381.

Firstly, scalarisation of v1i1 setcc operations simply fails if the
input types are legal. This is fixed in LegalizeVectorTypes.cpp this
time, and allows AArch64 code to be simplified slightly.

Second, vselect with such a setcc feeding into it ends up in
ScalarizeVectorOperand, where it's not handled. I experimented with an
implementation, but found that whatever DAG came out was rather
horrific. I think Hao's DAG combine approach is a good one for
quality, though there are edge cases it won't catch (to be fixed
separately).

Should fix PR19335.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205625 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 14:49:21 +00:00
Stepan Dyatkovskiy
148692bafe Fix for PR18921 (LDRD/STRD part)::
Removed "GNU Assembler extension (compatibility)" definitions from ARMInstrInfo.td
Fixed ARMAsmParser::ParseInstruction GNU compatability branch, so it also works for thumb mode from now.
Added new tests.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205622 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 10:17:56 +00:00
NAKAMURA Takumi
0670d7e47a Tweak unconditional-branch.ll passing on any hosts, while investigating x86_64-mingw32.
Sorry for the breakage.

For now, it will fail in two ways:

  1. To fail for targeting x86_64-mingw32.
    <stdin>:131:8: note: possible intended match here
    0x30830a0100000002 3 0 1 0 0 is_stmt

  2. To fail not to find the target x86.
    llc: : error: unable to get target for 'x86_64-unknown-unknown',
      see --version and --triple.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205621 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 10:16:51 +00:00
Tim Northover
0eb313be18 ARM64: use regalloc-friendly COPY_TO_REGCLASS for bitcasts
The previous patterns directly inserted FMOV or INS instructions into
the DAG for scalar_to_vector & bitconvert patterns. This is horribly
inefficient and can generated lots more GPR <-> FPR register traffic
than necessary.

It's much better to emit instructions the register allocator
understands so it can coalesce the copies when appropriate.

It led to at least one ISelLowering hack to avoid the problems, which
was incorrect for v1i64 (FPR64 has no dsub). It can now be removed
entirely.

This should also fix PR19331.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205616 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 09:03:09 +00:00
Tim Northover
604dff27c9 ARM64: add 128-bit MLA operations to the custom selection code.
Without this change, the llvm_unreachable kicked in. The code pattern
being spotted is rather non-canonical for 128-bit MLAs, but it can
happen and there's no point in generating sub-optimal code for it just
because it looks odd.

Should fix PR19332.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205615 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 09:03:02 +00:00
Stepan Dyatkovskiy
a669270654 Fixed register class in STRD instruction for Thumb2 mode.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205612 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 08:14:13 +00:00
Quentin Colombet
3b2b5dfa9b [RegAllocGreedy][Last Chance Recoloring] Emit diagnostics when last chance
recoloring cut-offs are encountered and register allocation failed.

This is related to PR18747

Patch by MAYUR PANDEY <mayur.p@samsung.com>.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205601 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 02:05:21 +00:00
Quentin Colombet
cc99615837 Revert r205599, the commit was not intended to have so many changes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205600 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 02:02:49 +00:00
Quentin Colombet
c65a77b92d [RegAllocGreedy][Last Chance Recoloring] Emit diagnostics when last chance
recoloring cut-offs are hit.

This is related to PR18747.

Patch by MAYUR PANDEY <mayur.p@samsung.com>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205599 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 01:58:57 +00:00
Saleem Abdulrasool
09ebd6d735 ARM: fix test case missed in previous roundup
This should hopefully bring the last MSVC buildbot back to green!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205596 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-04 01:19:56 +00:00
Rafael Espindola
7df9059541 Implement getRelocationAddress for MachO and ET_REL elf files.
With that, fix the symbolizer to work with any ELF file.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205588 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-03 23:54:35 +00:00
Saleem Abdulrasool
2abadea537 ARM: yet another round of ARM test clean ups
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205586 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-03 23:47:24 +00:00
Rafael Espindola
8cb805cf30 Fix llvm-objdump crash.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205581 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-03 23:20:02 +00:00
Eli Bendersky
25540a7f39 Optimize away unnecessary address casts.
Removes unnecessary casts from non-generic address spaces to the generic address
space for certain code patterns.

Patch by Jingyue Wu.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205571 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-03 21:18:25 +00:00
Lang Hames
89218827c8 [ARM64] Teach the ARM64DeadRegisterDefinition pass to respect implicit-defs.
When rematerializing through truncates, the coalescer may produce instructions
with dead defs, but live implicit-defs of subregs:
E.g.
  %X1<def,dead> = MOVi64imm 2, %W1<imp-def>; %X1:GPR64, %W1:GPR32

These instructions are live, and their definitions should not be rewritten.

Fixes <rdar://problem/16492408>



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@205565 91177308-0d34-0410-b5e6-96231b3b80d8
2014-04-03 20:51:08 +00:00