Commit Graph

111264 Commits

Author SHA1 Message Date
Michael Kuperstein
1f0ddef593 [DagCombine] Improve DAGCombiner BUILD_VECTOR when it has two sources of elements
This partially fixes PR21943.

For AVX, we go from:

vmovq   (%rsi), %xmm0
vmovq   (%rdi), %xmm1
vpermilps       $-27, %xmm1, %xmm2 ## xmm2 = xmm1[1,1,2,3]
vinsertps       $16, %xmm2, %xmm1, %xmm1 ## xmm1 = xmm1[0],xmm2[0],xmm1[2,3]
vinsertps       $32, %xmm0, %xmm1, %xmm1 ## xmm1 = xmm1[0,1],xmm0[0],xmm1[3]
vpermilps       $-27, %xmm0, %xmm0 ## xmm0 = xmm0[1,1,2,3]
vinsertps       $48, %xmm0, %xmm1, %xmm0 ## xmm0 = xmm1[0,1,2],xmm0[0]

To the expected:

vmovq   (%rdi), %xmm0
vmovhpd (%rsi), %xmm0, %xmm0
retq

Fixing this for AVX2 is still open.

Differential Revision: http://reviews.llvm.org/D6749

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224759 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 08:59:45 +00:00
Hal Finkel
775294d183 [PowerPC] Don't attempt a 64-bit pow2 division on PPC32
In r224033, in moving the signed power-of-2 division expansion into
BuildSDIVPow2, I accidentally made it possible to attempt the lowering for a
64-bit division on PPC32. This later asserts.

Fixes PR21928.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224758 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 08:38:50 +00:00
Michael Liao
b9e302f3ca [SimplifyCFG] Revise common code sinking
- Fix the case where more than 1 common instructions derived from the same
  operand cannot be sunk. When a pair of value has more than 1 derived values
  in both branches, only 1 derived value could be sunk.
- Replace BB1 -> (BB2, PN) map with joint value map, i.e.
  map of (BB1, BB2) -> PN, which is more accurate to track common ops.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224757 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 08:26:55 +00:00
Michael Kuperstein
fc86f5fc9f Remove a bad cast in CloneModule()
A cast that was introduced in r209007 was accidentally left in after the changes made to GlobalAlias rules in r210062. This crashes if the aliasee is a now-leggal ConstantExpr.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224756 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 08:23:45 +00:00
Ahmed Bougacha
bc47ceef43 [ARM] Don't break alignment when combining base updates into load/stores.
r223862/r224203 tried to also combine base-updating load/stores.
There was a mistake there: the alignment was added as is as an operand to
the ARMISD::VLD/VST node.  However, the VLD/VST selection logic doesn't care
about less-than-standard alignment attributes.
For example, no matter the alignment of a v2i64 load (say 1), SelectVLD picks
VLD1q64 (because of the memory type).  But VLD1q64 ("vld1.64 {dXX, dYY}") is
8-aligned, per ARMARMv7a 3.2.1.
For the 1-aligned load, what we really want is VLD1q8.

This commit introduces bitcasts if necessary, and changes the vld/vst type to
one whose standard alignment matches the original load/store alignment.

Differential Revision: http://reviews.llvm.org/D6759


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224754 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 06:07:31 +00:00
Alexey Samsonov
2f6ad0c00f Fix UBSan bootstrap: replace shift of negative value with multiplication.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224752 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 04:15:53 +00:00
Alexey Samsonov
acd25d2481 Fix UBSan bootstrap: don't bind reference to nullptr.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224751 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 04:15:47 +00:00
Chandler Carruth
d4510005df Revert r224739: Debug info: Teach SROA how to update debug info for
fragmented variables.

This caused codegen to start crashing when we built somewhat large
programs with debug info and optimizations. 'check-msan' hit in, and
I suspect a bootstrap would as well. I mailed a test case to the
review thread.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224750 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 02:58:14 +00:00
Jim Grosbach
860122b3b7 X86: Don't over-align combined loads.
When combining consecutive loads+inserts into a single vector load,
we should keep the alignment of the base load. Doing otherwise can, and does,
lead to using overly aligned instructions. In the included test case, for
example, using a 32-byte vmovaps on a 16-byte aligned value. Oops.

rdar://19190968

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224746 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-23 00:35:23 +00:00
Reid Kleckner
34b7fde802 Make musttail more robust for vector types on x86
Previously I tried to plug musttail into the existing vararg lowering
code. That turned out to be a mistake, because non-vararg calls use
significantly different register lowering, even on x86. For example, AVX
vectors are usually passed in registers to normal functions and memory
to vararg functions.  Now musttail uses a completely separate lowering.

Hopefully this can be used as the basis for non-x86 perfect forwarding.

Reviewers: majnemer

Differential Revision: http://reviews.llvm.org/D6156

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224745 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 23:58:37 +00:00
David Blaikie
b39244dca3 Remove dynamic allocation/indirection from GCOVBlocks owned by GCOVFunction
Since these are all created in the DenseMap before they are referenced,
there's no problem with pointer validity by the time it's required. This
removes another use of DeleteContainerSeconds/manual memory management
which I'm cleaning up from time to time.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224744 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 23:12:42 +00:00
Adrian Prantl
f5a21eaa18 Thumb1 frame lowering: Mark CFI instructions with the FrameSetup flag.
Followup to r224294:

ARM/AArch64: Attach the FrameSetup MIFlag to CFI instructions.
Debug info marks the first instruction without the FrameSetup flag
as being the end of the function prologue. Any CFI instructions in the
middle of the function prologue would cause debug info to end the prologue
too early and worse, attach the line number of the CFI instruction, which
incidentally is often 0.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224743 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 23:09:14 +00:00
Chandler Carruth
67924e9af8 [SROA] Lift the logic for traversing the alloca slices one partition at
a time into a partition iterator and a Partition class.

There is a lot of knock-on simplification that this enables, largely
stemming from having a Partition object to refer to in lots of helpers.
I've only done a minimal amount of that because enoguh stuff is changing
as-is in this commit.

This shouldn't change any observable behavior. I've worked hard to
preserve the *exact* traversal semantics which were originally present
even though some of them make no sense. I'll be changing some of this in
subsequent commits now that the logic is carefully factored into
a reusable place.

The primary motivation for this change is to break the rewriting into
phases in order to support more intelligent rewriting. For example, I'm
planning to change how split loads and stores are rewritten to remove
the significant overuse of integer bit packing in the resulting code and
allow more effective secondary splitting of aggregates. For any of this
to work, they have to share the exact traversal logic.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224742 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 22:46:00 +00:00
Bruno Cardoso Lopes
a559a2317c [LCSSA] Handle PHI insertion in disjoint loops
Take two disjoint Loops L1 and L2.

LoopSimplify fails to simplify some loops (e.g. when indirect branches
are involved). In such situations, it can happen that an exit for L1 is
the header of L2. Thus, when we create PHIs in one of such exits we are
also inserting PHIs in L2 header.

This could break LCSSA form for L2 because these inserted PHIs can also
have uses in L2 exits, which are never handled in the current
implementation. Provide a fix for this corner case and test that we
don't assert/crash on that.

Differential Revision: http://reviews.llvm.org/D6624

rdar://problem/19166231

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224740 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 22:35:46 +00:00
Adrian Prantl
e5ca21a2df Debug info: Teach SROA how to update debug info for fragmented variables.
This allows us to generate debug info for extremely advanced code such as

  typedef struct { long int a; int b;} S;

  int foo(S s) {
    return s.b;
  }

which at -O1 on x86_64 is codegen'd into

  define i32 @foo(i64 %s.coerce0, i32 %s.coerce1) #0 {
    ret i32 %s.coerce1, !dbg !24
  }

with this patch we emit the following debug info for this

  TAG_formal_parameter [3]
    AT_location( 0x00000000
                 0x0000000000000000 - 0x0000000000000006: rdi, piece 0x00000008, rsi, piece 0x00000004
                 0x0000000000000006 - 0x0000000000000008: rdi, piece 0x00000008, rax, piece 0x00000004 )
                 AT_name( "s" )
                 AT_decl_file( "/Volumes/Data/llvm/_build.ninja.release/test.c" )

Thanks to chandlerc, dblaikie, and echristo for their feedback on all
previous iterations of this patch!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224739 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 22:26:00 +00:00
Reid Kleckner
a834d6a4bb Fix Windows unwind info for functions in sections other than .text
Previously we assumed the section name had the form .text$foo, which is
what we used to do for inline functions. If the dollar wasn't present,
we'd put unwind data in the .pdata and .xdata sections for the main
.text section, which is incorrect.

Fixes PR22001.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224738 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 22:10:08 +00:00
Colin LeMahieu
9c0a115fbe [Hexagon] Adding memb instruction. Fixing whitespace in test from 224730.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224735 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 21:40:43 +00:00
David Blaikie
1b15304599 Use iterators rather than indices to make this forwards-compatible with a change to the underlying container (to std::list)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224734 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 21:26:38 +00:00
David Blaikie
d39a5d49b4 unique_ptrify MatchableInfo(const CodeGenInstAlias *Alias)'s parameter
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224733 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 21:26:26 +00:00
Colin LeMahieu
76be167773 [Hexagon] Adding classes and load unsigned byte instruction, updating usages.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224730 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 21:20:03 +00:00
Bruno Cardoso Lopes
ba059464c3 [x86] Add vector @llvm.ctpop intrinsic custom lowering
Currently, when ctpop is supported for scalar types, the expansion of
@llvm.ctpop.vXiY uses vector element extractions, insertions and individual
calls to @llvm.ctpop.iY. When not, expansion with bit-math operations is used
for the scalar calls.

Local haswell measurements show that we can improve vector @llvm.ctpop.vXiY
expansion in some cases by using a using a vector parallel bit twiddling
approach, based on:

v = v - ((v >> 1) & 0x55555555);
v = (v & 0x33333333) + ((v >> 2) & 0x33333333);
v = ((v + (v >> 4) & 0xF0F0F0F)
v = v + (v >> 8)
v = v + (v >> 16)
v = v & 0x0000003F
(from http://graphics.stanford.edu/~seander/bithacks.html#CountBitsSetParallel)

When scalar ctpop isn't supported, the approach above performs better for
v2i64, v4i32, v4i64 and v8i32 (see numbers below). And even when scalar ctpop
is supported, this approach performs ~2x better for v8i32.

Here, x86_64 implies -march=corei7-avx without ctpop and x86_64h includes ctpop
support with -march=core-avx2.

== [x86_64h - new]
v8i32: 0.661685
v4i32: 0.514678
v4i64: 0.652009
v2i64: 0.324289
== [x86_64h - old]
v8i32: 1.29578
v4i32: 0.528807
v4i64: 0.65981
v2i64: 0.330707

== [x86_64 - new]
v8i32: 1.003
v4i32: 0.656273
v4i64: 1.11711
v2i64: 0.754064
== [x86_64 - old]
v8i32: 2.34886
v4i32: 1.72053
v4i64: 1.41086
v2i64: 1.0244

More work for other vector types will come next.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224725 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 19:45:43 +00:00
Juergen Ributzka
ddba295642 Remove unused header. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224722 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 19:09:15 +00:00
Adrian Prantl
b2ebd4b426 Add a C++ marker to this header file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224721 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 19:07:45 +00:00
Peter Zotov
7bfc61dfe3 [C API] Expose LLVMGetGlobalValueAddress and LLVMGetFunctionAddress.
Patch by Ramkumar Ramachandra <artagnon@gmail.com>

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224720 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 18:53:11 +00:00
Quentin Colombet
7b88565334 [CodeGenPrepare] Handle properly the promotion of operands when this does not
generate instructions.

Fixes PR21978.
Related to <rdar://problem/18310086>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224717 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 18:11:52 +00:00
Elena Demikhovsky
c1aa521fb4 AVX-512: Added all forms of BLENDM instructions,
intrinsics, encoding tests for AVX-512F and skx instructions.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224707 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 13:52:48 +00:00
Karthik Bhat
0c2590a266 Lower multiply-negate operation to mneg on AArch64
This patch pattern matches code such as-
neg	 w8, w8
mul	 w8, w9, w8
to
mneg	 w8, w8, w9

Review: http://reviews.llvm.org/D6754



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224706 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 13:38:58 +00:00
Rafael Espindola
b646a4b0b8 Convert a few tests to FileCheck. NFC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224705 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 13:29:46 +00:00
Rafael Espindola
ada5f24b5f The leak detector is dead, long live asan and valgrind.
In resent times asan and valgrind have found way more memory management bugs
in llvm than the special purpose leak detector.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224703 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-22 13:00:36 +00:00
Saleem Abdulrasool
11dd9c3d55 CodeGen: minor style tweaks to SSP
Clean up some style related things in the StackProtector CodeGen.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224693 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-21 21:52:38 +00:00
Craig Topper
b10afb51d6 [X86] Add hasSideEffects = 0 to CALLpcrel16. This matches what is inferred from patterns for the 32-bit version.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224692 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-21 20:05:06 +00:00
Matt Arsenault
d796cf2e01 Enable (sext x) == C --> x == (trunc C) combine
Extend the existing code which handles this for zext. This makes this
more useful for targets with ZeroOrNegativeOne BooleanContent and
obsoletes a custom combine SI uses for i1 setcc (sext(i1), 0, setne)
since the constant will now be shrunk to i1.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224691 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-21 16:48:42 +00:00
Craig Topper
b8f8f2dbed [X86] Swap operand order in Intel syntax on a bunch of aliases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224687 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 23:05:59 +00:00
Craig Topper
a9bae8c3da [X86] Swap operand order of imul aliases in Intel syntax. Also disable printing of the alias instead of the real instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224686 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 23:05:57 +00:00
Craig Topper
0c8f0f0403 [X86] Remove '*' from asm strings in far call/jump aliases for Intel syntax.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224685 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 23:05:55 +00:00
Craig Topper
58331b67cb [X86] Don't swap the order of segment and offset in immediate form of far call/jump in Intel syntax.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224684 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 23:05:52 +00:00
Saleem Abdulrasool
281f568720 CodeGen: constify and use range loop for SSP
Use range-based for loop and constify the iterators.  NFC.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224683 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 21:37:51 +00:00
Saleem Abdulrasool
fc317b6e7b ARM: further improve deprecated diagnosis (LDM)
The ARM ARM states:
  LDM/LDMIA/LDMFD:
    The SP can be in the list. However, ARM deprecates using these instructions
    with SP in the list.

    ARM deprecates using these instructions with both the LR and the PC in the
    list.

  LDMDA/LDMFA/LDMDB/LDMEA/LDMIB/LDMED:
    The SP can be in the list. However, instructions that include the SP in the
    list are deprecated.

    Instructions that include both the LR and the PC in the list are deprecated.

  POP:
    The SP can only be in the list before ARMv7. ARM deprecates any use of ARM
    instructions that include the SP, and the value of the SP after such an
    instruction is UNKNOWN.

    ARM deprecates the use of this instruction with both the LR and the PC in
    the list.

Attempt to diagnose use of deprecated forms of these instructions.  This mirrors
the previous changes to diagnose use of the deprecated forms of STM in ARM mode.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224682 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 20:25:36 +00:00
David Majnemer
992d4bb278 strnlen isn't available on some platforms, use StringRef instead
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224679 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 08:24:43 +00:00
Craig Topper
ae39073d99 [X86] Immediate forms of far call/jump are not valid in x86-64.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224678 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 07:43:27 +00:00
David Majnemer
6df827240e This should have been part of r224676.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224677 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 04:48:34 +00:00
David Majnemer
854a37649a InstCombine: Squash an icmp+select into bitwise arithmetic
(X & INT_MIN) == 0 ? X ^ INT_MIN : X  into  X | INT_MIN
(X & INT_MIN) != 0 ? X ^ INT_MIN : X  into  X & INT_MAX

This fixes PR21993.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224676 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 04:45:35 +00:00
David Majnemer
821c6f765a InstSimplify: Don't bother if getScalarSizeInBits returns zero
getScalarSizeInBits returns zero when the comparison operands are not
integral.  No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224675 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 04:45:33 +00:00
David Majnemer
f666c0549e Simplify the code
No functionality change intended.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224673 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 03:29:59 +00:00
Eric Fiselier
2bea59bd02 Split executeShTest into two parts so that it can be better leveraged by libc++
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224672 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 03:23:53 +00:00
David Majnemer
9cd99a0724 InstSimplify: Optimize away pointless comparisons
(X & INT_MIN) ? X & INT_MAX : X  into  X & INT_MAX
(X & INT_MIN) ? X : X & INT_MAX  into  X
(X & INT_MIN) ? X | INT_MIN : X  into  X
(X & INT_MIN) ? X : X | INT_MIN  into  X | INT_MIN

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224669 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 03:04:38 +00:00
Chandler Carruth
93e03df3cf [SROA] Run clang-format over the entire SROA pass as I wrote it before
much of the glory of clang-format, and now any time I touch it I risk
introducing formatting changes as part of a functional commit.

Also, clang-format is *way* better at formatting my code than I am.
Most of this is a huge improvement although I reverted a couple of
places where I hit a clang-format bug with lambdas that has been filed
but not (fully) fixed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224666 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 02:39:18 +00:00
Chandler Carruth
795bfc9234 [x86] Change the test added in r223774 to first check the spelling of
the error message for a bogus processor, and then look specifically for
that error message using FileCheck.

I actually tried to write the test this way at first, but drew a blank
on how to ensure the error message stayed in sync (oops). Now that I've
recalled how to do that, this is clearly better.

It also fixes an issue with a malloc implementation that actually prints
to stderr in all cases, which was causing problems for some builders it
seems.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224665 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 02:19:22 +00:00
Matthias Braun
4acc514cc2 LiveIntervalAnalysis: No kill flags for partially undefined uses.
We must not add kill flags when reading a vreg with some undefined
subregisters, if subreg liveness tracking is enabled.  This is because
the register allocator may reuse these undefined subregisters for other
values which are not killed.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224664 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 01:54:50 +00:00
Matthias Braun
1f6bcf1b85 LiveIntervalAnalysis: cleanup addKills(), NFC
- Use more const modifiers
- Use references for things that can't be nullptr
- Improve some variable names

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@224663 91177308-0d34-0410-b5e6-96231b3b80d8
2014-12-20 01:54:48 +00:00