Commit Graph

17289 Commits

Author SHA1 Message Date
Benjamin Kramer
7182126b0f Indvars: Don't recursively delete instruction during BB iteration.
This can invalidate the iterators leading to use after frees and crashes.
Fixes PR12536.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166291 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-19 17:53:54 +00:00
Michael Liao
facace808c Lower BUILD_VECTOR to SHUFFLE + INSERT_VECTOR_ELT for X86
- If INSERT_VECTOR_ELT is supported (above SSE2, either by custom
  sequence of legal insn), transform BUILD_VECTOR into SHUFFLE +
  INSERT_VECTOR_ELT if most of elements could be built from SHUFFLE with few
  (so far 1) elements being inserted.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166288 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-19 17:15:18 +00:00
Benjamin Kramer
239fd44f7a SCEVExpander: Don't crash when trying to merge two constant phis.
Just constant fold them so they can't cause any trouble. Fixes PR12627.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166286 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-19 16:37:30 +00:00
Stepan Dyatkovskiy
0d3c8d5d16 ARM:
Removed extra stack frame object for fixed byval arguments,
VarArgsStyleRegisters invocation was reworked due to some improper usage in
past. PR14099 also demonstrates it.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166273 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-19 08:23:06 +00:00
Kostya Serebryany
bd0052a0f2 [asan] make sure asan erases old unused allocas after it created a new one. This became important after the recent move from ModulePass to FunctionPass because no cleanup is happening after asan pass any more.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166267 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-19 06:20:53 +00:00
Nadav Rotem
89e7b356f2 vectorizer: Add support for reading and writing from the same memory location.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166255 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-19 01:24:18 +00:00
Bob Wilson
82c5180ed1 Mark bugpoint tests with XFAIL when building with LTO. <rdar://problem/12473675>
The LTO Internalize pass is hiding symbols needed by the bugpoint-passes
plug-in.  We need to add a flag to control whether Internalize should be run.
This is a temporary workaround to make these tests pass in the meantime.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166239 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 22:03:31 +00:00
Daniel Dunbar
b288ad8e36 test: Add a lit config variable to check if LTO is enabled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166225 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 20:43:11 +00:00
Sebastian Pop
92c39cadbc Use pre-python 2.5 syntax in lit.cfg.
Author:    Quentin Neill <qneill@codeaurora.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166217 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 19:58:28 +00:00
Sebastian Pop
83ba06afa8 Clear unknown mem ops when merging stack slots (pr14090)
When merging stack slots, if StackColoring::remapInstructions gets a
value back from GetUnderlyingObject that it does not know about or is
not itself a stack slot, clear the memory operand in case it aliases
the merged slot. This prevents the introduction of incorrect aliasing
information.

Author:    Matthew Curtis <mcurtis@codeaurora.org>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166216 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 19:53:48 +00:00
Meador Inge
0c41d57b09 instcombine: Migrate strcpy optimizations
This patch migrates the strcpy optimizations from the simplify-libcalls pass
into the instcombine library call simplifier.  Note also that StrCpyChkOpt
has been updated with a few simplifications that were being done in the
simplify-libcalls version of StrCpyOpt, but not in the migrated implementation
of StrCpyOpt.  There is no reason to overload StrCpyOpt with fortified and
regular simplifications in the new model since there is already a dedicated
simplifier for __strcpy_chk.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166198 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 18:12:40 +00:00
Nadav Rotem
1c5bf3f429 In SimplifySelectOps we pulled two loads through a select node despite the fact that one was dependent on the other.
rdar://12513091



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166196 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 18:06:48 +00:00
Ulrich Weigand
6c28a7eec8 This patch fixes failures in the SingleSource/Regression/C/uint64_to_float
test case on PowerPC caused by rounding errors when converting from a 64-bit
integer to a single-precision floating point. The reason for this are
double-rounding effects, since on PowerPC we have to convert to an
intermediate double-precision value first, which gets rounded to the
final single-precision result.

The patch fixes the problem by preparing the 64-bit integer so that the
first conversion step to double-precision will always be exact, and the
final rounding step will result in the correctly-rounded single-precision
result.  The generated code sequence is equivalent to what GCC would generate.

When -enable-unsafe-fp-math is in effect, that extra effort is omitted
and we accept possible rounding errors (just like GCC does as well).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166178 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 13:16:11 +00:00
Nadav Rotem
1953ace81d Vectorizer: Add support for loops with an unknown count. For example:
for (i=0; i<n; i++){
        a[i] = b[i+1] + c[i+3];
     }



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166165 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-18 05:29:12 +00:00
Michael Liao
07edaf3801 Revert part of r166049 back and enable test case in r166125.
- Folding (trunc (concat ... X )) to (concat ... (trunc X) ...) is valid
  when '...' are all 'undef's.
- r166125 relies on this transformation.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166155 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 23:45:54 +00:00
Michael Liao
6e0c2b36d6 Disable extract-concat test case temporarily
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166141 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 23:08:19 +00:00
Michael Liao
4031e9018b Revert r166049
- In general, it's unsafe for this transformation.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166135 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 22:41:15 +00:00
Reed Kotler
95a2bb4cdf Add conditional branch instructions and their patterns.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166134 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 22:29:54 +00:00
Michael Liao
13429e224c Teach DAG combine to fold (extract_subvec (concat v1, ..) i) to v_i
- If the extracted vector has the same type of all vectored being concatenated
  together, it should be simplified directly into v_i, where i is the index of
  the element being extracted.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166125 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 20:48:33 +00:00
Nadav Rotem
d15c0c7ac1 Add a loop vectorizer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166112 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 18:25:06 +00:00
Anton Korobeynikov
e4b33a115b Fix fallout from RegInfo => FrameLowering refactoring on MSP430.
Patch by Job Noorman!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166108 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 17:37:11 +00:00
Chandler Carruth
02bf98ab38 This just in, it is a *bad idea* to use 'udiv' on an offset of
a pointer. A very bad idea. Let's not do that. Fixes PR14105.

Note that this wasn't *that* glaring of an oversight. Originally, these
routines were only called on offsets within an alloca, which are
intrinsically positive. But over the evolution of the pass, they ended
up being called for arbitrary offsets, and things went downhill...

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166095 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 09:23:48 +00:00
Michael Liao
281ae5abf5 Fix setjmp on models with non-Small code model nor non-Static relocation model
- MBB address is only valid as an immediate value in Small & Static
  code/relocation models. On other models, LEA is needed to load IP address of
  the restore MBB.
- A minor fix of MBB in MC lowering is added as well to enable target
  relocation flag being propagated into MC.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166084 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-17 02:22:27 +00:00
Jakob Stoklund Olesen
320db3f805 Avoid rematerializing a redef immediately after the old def.
PR14098 contains an example where we would rematerialize a MOV8ri
immediately after the original instruction:

  %vreg7:sub_8bit<def> = MOV8ri 9; GR32_ABCD:%vreg7
  %vreg22:sub_8bit<def> = MOV8ri 9; GR32_ABCD:%vreg7

Besides being pointless, it is also wrong since the original instruction
only redefines part of the register, and the value read by the new
instruction is wrong.

The problem was the LiveRangeEdit::allUsesAvailableAt() didn't
special-case OrigIdx == UseIdx and found the wrong SSA value.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166068 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 22:51:58 +00:00
Jakob Stoklund Olesen
cdcdfd2cab Revert r166046 "Switch back to the old coalescer for now to fix the 32 bit bit"
A fix for PR14098, including the test case is in the next commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166067 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 22:51:55 +00:00
Michael Gottesman
4932bbe20c [InstCombine] Teach InstCombine how to handle an obfuscated splat.
An obfuscated splat is where the frontend poorly generates code for a splat
using several different shuffles to create the splat, i.e.,

  %A = load <4 x float>* %in_ptr, align 16
  %B = shufflevector <4 x float> %A, <4 x float> undef, <4 x i32> <i32 0, i32 0, i32 undef, i32 undef>
  %C = shufflevector <4 x float> %B, <4 x float> %A, <4 x i32> <i32 0, i32 1, i32 4, i32 undef>
  %D = shufflevector <4 x float> %C, <4 x float> %A, <4 x i32> <i32 0, i32 1, i32 2, i32 4>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166061 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 21:29:38 +00:00
Michael Liao
272ea03239 Teach DAG combine to fold (trunc (fptoXi x)) to (fptoXi x)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166049 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 19:38:35 +00:00
Rafael Espindola
6f7cccd2e2 Switch back to the old coalescer for now to fix the 32 bit bit
llvm+clang+compiler-rt bootstrap.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166046 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 19:34:06 +00:00
Bill Schmidt
7a6cb15a92 This patch addresses PR13949.
For the PowerPC 64-bit ELF Linux ABI, aggregates of size less than 8
bytes are to be passed in the low-order bits ("right-adjusted") of the
doubleword register or memory slot assigned to them.  A previous patch
addressed this for aggregates passed in registers.  However, small
aggregates passed in the overflow portion of the parameter save area are
still being passed left-adjusted.

The fix is made in PPCTargetLowering::LowerCall_Darwin_Or_64SVR4 on the
caller side, and in PPCTargetLowering::LowerFormalArguments_64SVR4 on
the callee side.  The main fix on the callee side simply extends
existing logic for 1- and 2-byte objects to 1- through 7-byte objects,
and correcting a constant left over from 32-bit code.  There is also a
fix to a bogus calculation of the offset to the following argument in
the parameter save area.

On the caller side, again a constant left over from 32-bit code is
fixed.  Additionally, some code for 1, 2, and 4-byte objects is
duplicated to handle the 3, 5, 6, and 7-byte objects for SVR4 only.  The
LowerCall_Darwin_Or_64SVR4 logic is getting fairly convoluted trying to
handle both ABIs, and I propose to separate this into two functions in a
future patch, at which time the duplication can be removed.

The patch adds a new test (structsinmem.ll) to demonstrate correct
passing of structures of all seven sizes.  Eight dummy parameters are
used to force these structures to be in the overflow portion of the
parameter save area.

As a side effect, this corrects the case when aggregates passed in
registers are saved into the first eight doublewords of the parameter
save area:  Previously they were stored left-justified, and now are
properly stored right-justified.  This requires changing the expected
output of existing test case structsinregs.ll.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166022 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 13:30:53 +00:00
Stepan Dyatkovskiy
b52ba9f8a8 Issue:
Stack is formed improperly for long structures passed as byval arguments for
EABI mode.

If we took AAPCS reference, we can found the next statements:

A: "If the argument requires double-word alignment (8-byte), the NCRN (Next
Core Register Number) is rounded up to the next even register number." (5.5
Parameter Passing, Stage C, C.3).

B: "The alignment of an aggregate shall be the alignment of its most-aligned
component." (4.3 Composite Types, 4.3.1 Aggregates).

So if we have structure with doubles (9 double fields) and 3 Core unused
registers (r1, r2, r3): caller should use r2 and r3 registers only.
Currently r1,r2,r3 set is used, but it is invalid.

Callee VA routine should also use r2 and r3 regs only. All is ok here. This
behaviour is guessed by rounding up SP address with ADD+BFC operations.

Fix:
Main fix is in ARMTargetLowering::HandleByVal. If we detected AAPCS mode and
8 byte alignment, we waste odd registers then.

P.S.:
I also improved LDRB_POST_IMM regression test. Since ldrb instruction will
not generated by current regression test after this patch. 


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166018 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 07:16:47 +00:00
NAKAMURA Takumi
e26874556b Reapply r165661, Patch by Shuxin Yang <shuxin.llvm@gmail.com>.
Original message:

The attached is the fix to radar://11663049. The optimization can be outlined by following rules:

   (select (x != c), e, c) -> select (x != c), e, x),
   (select (x == c), c, e) -> select (x == c), x, e)
where the <c> is an integer constant.

 The reason for this change is that : on x86, conditional-move-from-constant needs two instructions;
however, conditional-move-from-register need only one instruction.

  While the LowerSELECT() sounds to be the most convenient place for this optimization, it turns out to be a bad place. The reason is that by replacing the constant <c> with a symbolic value, it obscure some instruction-combining opportunities which would otherwise be very easy to spot. For that reason, I have to postpone the change to last instruction-combining phase.

  The change passes the test of "make check-all -C <build-root/test" and "make -C project/test-suite/SingleSource".

Original message since r165661:

My previous change has a bug: I negated the condition code of a CMOV, and go ahead creating a new CMOV using the *ORIGINAL* condition code.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166017 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 06:28:34 +00:00
Rafael Espindola
0cead1cfef Fix the cpu name and add -verify-machineinstrs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166003 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 01:13:06 +00:00
Andrew Trick
27c28cef11 misched: Added handleMove support for updating all kill flags, not just for allocatable regs.
This is a medium term workaround until we have a more robust solution
in the form of a register liveness utility for postRA passes.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@166001 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-16 00:22:51 +00:00
Michael Liao
6c0e04c823 Add __builtin_setjmp/_longjmp supprt in X86 backend
- Besides used in SjLj exception handling, __builtin_setjmp/__longjmp is also
  used as a light-weight replacement of setjmp/longjmp which are used to
  implementation continuation, user-level threading, and etc. The support added
  in this patch ONLY addresses this usage and is NOT intended to support SjLj
  exception handling as zero-cost DWARF exception handling is used by default
  in X86.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165989 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 22:39:43 +00:00
Jim Grosbach
64ba635209 ARM: v1i64 and v2i64 VBSL intrinsic support.
rdar://12502028

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165981 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 21:23:40 +00:00
David Blaikie
66d4b0fbf4 Add dependency on llvm-bcanalyzer from tests to the CMake build.
This fixes a CMake build break introduced by r165739.

Thanks Jan Voung for the quick suggestion/fix.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165978 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 21:11:46 +00:00
Andrew Trick
874c0a6ec7 Check output of the misched unit tests
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165959 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 20:33:14 +00:00
Rafael Espindola
32522201a8 Add a cpu to try to fix the atom builder.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165956 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 19:25:43 +00:00
Rafael Espindola
3da6f0392a Add testcase for pr14088.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165954 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 19:00:10 +00:00
Andrew Trick
bb20b24224 misched tests: add a triple to speculatively fix windows builders.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165952 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 18:21:08 +00:00
Andrew Trick
1e94e98b0e misched: ILP scheduler for experimental heuristics.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165950 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 18:02:27 +00:00
Kostya Serebryany
2611eeda98 [asan] fix a test
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165938 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 14:30:30 +00:00
Chandler Carruth
d2cd73f6a5 Update the memcpy rewriting to fully support widened int rewriting. This
includes extracting ints for copying elsewhere and inserting ints when
copying into the alloca. This should fix the CanSROA assertion coming
out of Clang's regression test suite.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165931 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 10:24:43 +00:00
Chandler Carruth
94fc64c42f Follow-up fix to r165928: handle memset rewriting for widened integers,
and generally clean up the memset handling. It had rotted a bit as the
other rewriting logic got polished more.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165930 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 10:24:40 +00:00
Silviu Baranga
bb1078ea13 Fixed PR13938: the ARM backend was crashing because it couldn't select a VDUPLANE node with the vector input size different from the output size. This was bacause the BUILD_VECTOR lowering code didn't check that the size of the input vector was correct for using VDUPLANE.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165929 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 09:41:32 +00:00
Chandler Carruth
81ff90db44 First major step toward addressing PR14059. This teaches SROA to handle
cases where we have partial integer loads and stores to an otherwise
promotable alloca to widen[1] those loads and stores to cover the entire
alloca and bitcast them into the appropriate type such that promotion
can proceed.

These partial loads and stores stem from an annoying confluence of ARM's
calling convention and ABI lowering and the FCA pre-splitting which
takes place in SROA. Clang lowers a { double, double } in-register
function argument as a [4 x i32] function argument to ensure it is
placed into integer 32-bit registers (a really unnerving implicit
contract between Clang and the ARM backend I would add). This results in
a FCA load of [4 x i32]* from the { double, double } alloca, and SROA
decomposes this into a sequence of i32 loads and stores. Inlining
proceeds, code gets folded, but at the end of the day, we still have i32
stores to the low and high halves of a double alloca. Widening these to
be i64 operations, and bitcasting them to double prior to loading or
storing allows promotion to proceed for these allocas.

I looked quite a bit changing the IR which Clang produces for this case
to be more friendly, but small changes seem unlikely to help. I think
the best representation we could use currently would be to pass 4 i32
arguments thereby avoiding any FCAs, but that would still require this
fix. It seems like it might eventually be nice to somehow encode the ABI
register selection choices outside of the parameter type system so that
the parameter can be a { double, double }, but the CC register
annotations indicate that this should be passed via 4 integer registers.

This patch does not address the second problem in PR14059, which is the
reverse: when a struct alloca is loaded as a *larger* single integer.

This patch also does not address some of the code quality issues with
the FCA-splitting. Those don't actually impede any optimizations really,
but they're on my list to clean up.

[1]: Pedantic footnote: for those concerned about memory model issues
here, this is safe. For the alloca to be promotable, it cannot escape or
have any use of its address that could allow these loads or stores to be
racing. Thus, widening is always safe.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165928 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 08:40:30 +00:00
Meador Inge
a239c2e6a7 instcombine: Migrate strcmp and strncmp optimizations
This patch migrates the strcmp and strncmp optimizations from the
simplify-libcalls pass into the instcombine library call simplifier.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165915 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-15 03:47:37 +00:00
Benjamin Kramer
08b6b81ec5 X86: Depending on the local semantics of .align this test can also emit a nopl instead of nopw.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165880 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-13 17:38:00 +00:00
Benjamin Kramer
126afcbf65 X86: Disable long nops for all cpus prior to pentiumpro/i686.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165878 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-13 17:28:35 +00:00
Jakob Stoklund Olesen
d86296a4ae Drop <def,dead> flags when merging into an unused lane.
The new coalescer can merge a dead def into an unused lane of an
otherwise live vector register.

Clear the <dead> flag when that happens since the flag refers to the
full virtual register which is still live after the partial dead def.

This fixes PR14079.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@165877 91177308-0d34-0410-b5e6-96231b3b80d8
2012-10-13 17:26:47 +00:00