31575 Commits

Author SHA1 Message Date
Sanjay Patel
b730bdf4e9 [x86] enable machine combiner reassociations for 128-bit vector min/max
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245715 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 18:06:49 +00:00
Sanjay Patel
c9cb569d1e save some testing time; get rid of the non-SSE chips in this test
It doesn't matter what slow/fast unaligned attribute the old chips
have - they can't use anything more than 4-byte stores.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245709 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 17:16:51 +00:00
Sanjay Patel
67f79f0519 add a test case to check the fast-unaligned-mem attribute per CPU
This will confirm that the patch in D12154 is actually NFC.
It will also confirm that the proposed changes for the AMD chips
are behaving as expected.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245704 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 16:08:26 +00:00
John Brawn
19a3f63b54 [DAGCombiner] Fold together mul and shl when both are by a constant
This is intended to improve code generation for GEPs, as the index value is
shifted by the element size and in GEPs of multi-dimensional arrays the index
of higher dimensions is multiplied by the lower dimension size.

Differential Revision: http://reviews.llvm.org/D12197


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245689 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 10:48:17 +00:00
NAKAMURA Takumi
92c2acd055 Revert r245635, "[InstCombine] Transform A & (L - 1) u< L --> L != 0"
It caused miscompilation in clang.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245678 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 07:46:07 +00:00
James Y Knight
83b0a9bc74 [Sparc] Support user-specified stack object overalignment.
Note: I do not implement a base pointer, so it's still impossible to
have dynamic realignment AND dynamic alloca in the same function.

This also moves the code for determining the frame index reference
into getFrameIndexReference, where it belongs, instead of inline in
eliminateFrameIndex.

[Begin long-winded screed]

Now, stack realignment for Sparc is actually a silly thing to support,
because the Sparc ABI has no need for it -- unlike the situation on
x86, the stack is ALWAYS aligned to the required alignment for the CPU
instructions: 8 bytes on sparcv8, and 16 bytes on sparcv9.

However, LLVM unfortunately implements user-specified overalignment
using stack realignment support, so for now, I'm going to go along
with that tradition. GCC instead treats objects which have alignment
specification greater than the maximum CPU-required alignment for the
target as a separate block of stack memory, with their own virtual
base pointer (which gets aligned). Doing it that way avoids needing to
implement per-target support for stack realignment, except for the
targets which *actually* have an ABI-specified stack alignment which
is too small for the CPU's requirements.

Further unfortunately in LLVM, the default canRealignStack for all
targets effectively returns true, despite that implementing that is
something a target needs to do specifically. So, the previous behavior
on Sparc was to silently ignore the user's specified stack
alignment. Ugh.

Yet MORE unfortunate, if a target actually does return false from
canRealignStack, that also causes the user-specified alignment to be
*silently ignored*, rather than emitting an error.

(I started looking into fixing that last, but it broke a bunch of
tests, because LLVM actually *depends* on having it silently ignored:
some architectures (e.g. non-linux i386) have smaller stack alignment
than spilled-register alignment. But, the fact that a register needs
spilling is not known until within the register allocator. And by that
point, the decision to not reserve the frame pointer has been frozen
in place. And without a frame pointer, stack realignment is not
possible. So, canRealignStack() returns false, and
needsStackRealignment() then returns false, assuming everyone can just
go on their merry way assuming the alignment requirements were
probably just suggestions after-all. Sigh...)

Differential Revision: http://reviews.llvm.org/D12208

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245668 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 04:17:56 +00:00
Peter Collingbourne
c1e784cb78 TransformUtils: Introduce module splitter.
The module splitter splits a module into linkable partitions. It will
be used to implement parallel LTO code generation.

This initial version of the splitter does not attempt to deal with the
somewhat subtle symbol visibility issues around module splitting. These
will be dealt with in a future change.

Differential Revision: http://reviews.llvm.org/D12132

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245662 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 02:48:20 +00:00
Matthias Braun
7f0a6c950c AArch64: Fix testcase of r245640
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245647 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 00:23:19 +00:00
Michael Zolotukhin
3dc9abd7c5 [SLP] Add one more test case for propagating 'nontemporal' attributes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245644 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 00:08:39 +00:00
Adrian Prantl
6973889a62 delete more dead code from this testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245643 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-21 00:02:04 +00:00
Adrian Prantl
37d4cd87a1 Further reduce the IR in this testcase based on a further reduction
of the original source by David Blaikie (thanks!).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245642 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 23:59:39 +00:00
Matthias Braun
57970eb1a0 AArch64: Fix cmp;ccmp ordering
When producing conditional compare sequences for or operations we need
to negate the operands and the finally tested flags. The thing is if we negate
the finally tested flags this equals a logical negation of all previously
emitted expressions. There was a case missing where we have to order OR
expressions so they get emitted first.

This fixes http://llvm.org/PR24459

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245641 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 23:33:34 +00:00
Matthias Braun
05b3080b3c AArch64: Do not create CCMP on multiple users.
Create CMP;CCMP sequences from and/or trees does not gain us anything if
the and/or tree is materialized to a GP register anyway. While most of
the code already checked for hasOneUse() there was one important case
missing.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245640 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 23:33:31 +00:00
David Majnemer
bdab9f9f82 [InstSimplify] add nuw %x, C2 must be at least C2
Use the fact that add nuw always creates a larger bit pattern when
trying to simplify comparisons.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245638 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 23:01:41 +00:00
Sanjoy Das
ba38902605 [InstCombine] Transform A & (L - 1) u< L --> L != 0
Summary:
This transform is never a pessimization at the IR level (since it
replaces an `icmp` with another), and has potentiall payoffs:

 1. It may make the `icmp` fold away or become loop invariant.
 2. It may make the `A & (L - 1)` computation dead.

This shows up in Java, in range checks generated by array accesses of
the form `a[i & (a.length - 1)]`.

Reviewers: reames, majnemer

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D12210

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245635 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 22:31:55 +00:00
Michael Zolotukhin
9cd73adba0 [SLP] Propagate 'nontemporal' attribute into vectorized instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245633 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 22:28:15 +00:00
Michael Zolotukhin
c23d147533 [LoopVectorize] Propagate 'nontemporal' attribute into vectorized instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245632 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 22:27:38 +00:00
Ahmed Bougacha
14fea5bf0d [X86] Look for scalar through one bitcast when lowering to VBROADCAST.
Fixes PR23464: one way to use the broadcast intrinsics is:

  _mm256_broadcastw_epi16(_mm_cvtsi32_si128(*(int*)src));

We don't currently fold this, but now that we use native IR for
the intrinsics (r245605), we can look through one bitcast to find
the broadcast scalar.

Differential Revision: http://reviews.llvm.org/D10557


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245613 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 21:02:39 +00:00
Ahmed Bougacha
ed7eb85a5d [X86] Add some broadcast-from-memory tests.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245612 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 20:59:41 +00:00
Jingyue Wu
1670bbc481 [NVPTX] truncating 64-bit to 32-bit is free
Summary:
Add an LSR test that exercises isTruncateFree. Without this change, LSR creates
another indvar representing the truncated value.

Reviewers: jholewinski, eliben

Subscribers: jholewinski, llvm-commits

Differential Revision: http://reviews.llvm.org/D12058

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245611 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 20:59:02 +00:00
Ahmed Bougacha
ad0ddd8e01 [X86] Replace avx2 broadcast intrinsics with native IR.
Since r245605, the clang headers don't use these anymore.
r245165 updated some of the tests already; update the others, add
an autoupgrade, remove the intrinsics, and cleanup the definitions.

Differential Revision: http://reviews.llvm.org/D10555


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245606 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 20:36:19 +00:00
Adrian Prantl
2c12b35c95 Fix a bug that caused SimplifyCFG to drop DebugLocs.
Instruction::dropUnknownMetadata(KnownSet) is supposed to preserve all
metadata in KnownSet, but the condition for DebugLocs was inverted.

Most users of dropUnknownMetadata() actually worked around this by not
adding LLVMContext::MD_dbg to their list of KnowIDs.
This is now made explicit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245589 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 18:24:02 +00:00
Adrian Prantl
0f8344c168 Fix a debug location handling bug in GVN.
Caught by the famous "DebugLoc describes the currect SubProgram" assertion.

When GVN is removing a nonlocal load it updates the debug location of the
SSA value it replaced the load with with the one of the load. In the
testcase this actually overwrites a valid debug location with an empty one.

In reality GVN has to make an arbitrary choice between two equally valid
debug locations. This patch changes to behavior to only update the
location if the value doesn't already have a debug location.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245588 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 18:23:56 +00:00
Rafael Espindola
9a6dbcb2d8 Fix symbol value computation when part of the expression is weak.
This matches the behaviour of the gnu assembler and is part of
fixing pr24486.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245576 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 16:18:30 +00:00
Douglas Katzman
950d9fd449 [Sparc]: correct the 'set' synthetic instruction
Differential Revision: http://reviews.llvm.org/D12194

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245575 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 16:16:16 +00:00
Balaram Makam
b2026a6a18 Optimize bitwise even/odd test (-x&1 -> x&1) to not use negation.
Summary: We know that -x & 1 is equivalent to x & 1, avoid using negation for testing if a negative integer is even or odd.

Reviewers: majnemer

Subscribers: junbuml, mssimpso, gberry, mcrosier, llvm-commits

Differential Revision: http://reviews.llvm.org/D12156

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245569 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 15:35:00 +00:00
Zoran Jovanovic
9a4e2cb329 [mips][microMIPS] Add microMIPS32r6 and microMIPS64r6 tests for existing 16-bit ADDIUR1SP, ADDIUR2, ADDIUS5 and ADDIUSP instructions
Differential Revision: http://reviews.llvm.org/D10955


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245554 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 11:51:49 +00:00
Marina Yatsina
4ca59ab261 [X86] Fix FBLD and FBSTP
FBLD and FBSTP should receive TBYTE because it is defined as
FBLD m80
FBSTP m80

Differential Revision: http://reviews.llvm.org/D11748



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245553 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 11:51:24 +00:00
Marina Yatsina
8d1c57faee [X86] Fix bug in COMISD and COMISS definition in td files
COMISD should receive QWORD because it is defined as
 (V)COMISD xmm1, xmm2/m64

COMISS should receive DWORD because it is defined as
 (V)COMISS xmm1, xmm2/m32

Differential Revision: http://reviews.llvm.org/D11712



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245551 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 11:21:36 +00:00
David Majnemer
fa1aef3608 [X86] Fix the (shl (and (setcc_c), c1), c2) -> (and setcc_c, (c1 << c2)) fold
We didn't check for the necessary preconditions before folding a
mask/shift into a single mask.

This fixes PR24516.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245544 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 09:00:56 +00:00
Bjorn Steinbrink
0299ff2d55 Revert "[DSE] Enable removal of lifetime intrinsics in terminating blocks"
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245543 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 08:58:47 +00:00
Bjorn Steinbrink
1ca4f6f1ca [DSE] Enable removal of lifetime intrinsics in terminating blocks
Usually DSE is not supposed to remove lifetime intrinsics, but it's
actually ok to remove them for dead objects in terminating blocks,
because they convey no extra information there. Until we hit a lifetime
start that cannot be removed, that is. Because from that point on the
lifetime intrinsics become interesting again, e.g. for stack coloring.

Reviewers: reames

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D11710

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245542 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 08:25:28 +00:00
Hal Finkel
d51dd69e79 [PowerPC] Fix value type on XVCMPEQDP for v2f64 comparisons
XVCMPEQDP is used for VSX v2f64 equality comparisons, but the value type needs
to be v2i64 (as that's the corresponding SETCC type).

Fixes PR24225.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245535 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 03:02:02 +00:00
Hal Finkel
c2b62e02e8 [PowerPC] Fix the int2fp(fp2int(x)) DAGCombine to ignore ppc_fp128
This DAGCombine was creating custom SDAG nodes with an illegal ppc_fp128
operand type because it was triggering on f64/f32 int2fp(fp2int(ppc_fp128 x)),
but shouldn't (it should only apply to f32/f64 types). The result was a crash.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245530 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 01:18:20 +00:00
Alex Lorenz
e2e6dea9f2 MIR Serialization: Use the global value syntax for global value memory operands.
This commit modifies the serialization syntax so that the global IR values in
machine memory operands use the global value '@<name>' syntax instead of the
current '%ir.<name>' syntax.

The unnamed global IR values are handled by this commit as well, as the
existing global value parsing method can parse the unnamed globals already.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245527 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 00:20:03 +00:00
Alex Lorenz
77676424fd MIR Serialization: Change syntax for the call entry pseudo source values.
The global IR values in machine memory operands should use the global value
'@<name>' syntax instead of the current '%ir.<name>' syntax.

However, the global value call entry pseudo source values use the global value
syntax already. Therefore, the syntax for the call entry pseudo source values
has to be changed so that the global values and call entry global value PSVs
can be parsed without ambiguities.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245526 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-20 00:12:57 +00:00
Alex Lorenz
e8a419727a MIR Serialization: Serialize unnamed local IR values in memory operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245521 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 23:31:05 +00:00
Sanjay Patel
3b7c3d3fe9 [x86] enable machine combiner reassociations for scalar double-precision min/max
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245506 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 21:27:27 +00:00
Sanjay Patel
d81980d640 [x86] enable machine combiner reassociations for scalar single-precision maximums
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245504 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 21:18:46 +00:00
Simon Pilgrim
0898cdd518 [DAGCombiner] Added SMAX/SMIN/UMAX/UMIN constant folding
We still need to add constant folding of vector comparisons to fold the tests for targets that don't support the respective min/max nodes

I needed to update 2011-12-06-AVXVectorExtractCombine to load a vector instead of using a constant vector to prevent it folding

Differential Revision: http://reviews.llvm.org/D12118

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245503 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 21:11:58 +00:00
Juergen Ributzka
58f4f24a6e [AArch64][FastISel] Don't fold shifts with UB.
We are already falling back to SelectionDAG when encountering an shift with UB.
This adds the same checks for shifts with UB that get folded into arithmetic or
logical operations.

This fixes rdar://problem/22345295.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245499 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 20:52:55 +00:00
David Majnemer
26047ead4b [X86] Emit more efficient >= comparisons against 0
We don't do a great job with >= 0 comparisons against zero when the
result is used as an i8.

Given something like:
  void f(long long LL, bool *B) {
    *B = LL >= 0;
  }

We used to generate:
  shrq    $63, %rdi
  xorb    $1, %dil
  movb    %dil, (%rsi)

Now we generate:
  testq   %rdi, %rdi
  setns   (%rsi)

Differential Revision: http://reviews.llvm.org/D12136

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245498 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 20:51:40 +00:00
Dan Gohman
6e53cbdf5f [WebAssembly] Use the default alignment for SIMD types.
Previously WebAssembly's datalayout string had -v128:8:128. This had been an
attempt to declare a certain level of support for unaligned SIMD accesses.
However, clang makes its own determinations for SIMD alignment that are
independent of the datalayout string, so this wasn't actually meaningful.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245494 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 20:30:20 +00:00
Simon Pilgrim
4d3b3bf51b [DAGCombiner] Fold CONCAT_VECTORS of EXTRACT_SUBVECTOR (or undef) to VECTOR_SHUFFLE.
Check to see if this is a CONCAT_VECTORS of a bunch of EXTRACT_SUBVECTOR operations. If so, and if the EXTRACT_SUBVECTOR vector inputs come from at most two distinct vectors the same size as the result, attempt to turn this into a legal shuffle.

Differential Revision: http://reviews.llvm.org/D12125

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245490 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 20:09:50 +00:00
Paul Robinson
fd86e6dde8 Minor tidying of regex in a test
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245486 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 19:36:35 +00:00
Douglas Katzman
73e587e7f9 [Sparc]: asm-only support for the ldstub instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245485 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 19:30:57 +00:00
Alex Lorenz
dab6ae0096 MIR Serialization: Serialize instruction's register ties.
This commit serializes the machine instruction's register operand ties.
The ties are printed out only when the instructon has register ties that are
different from the ties that are specified in the instruction's description.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245482 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 19:05:34 +00:00
Nemanja Ivanovic
b326c1268c Temporary fix for the self-host failures introduced by rL244921.
This revision has introduced an issue that only affects bootstrapped compiler
when it is printing the ASM. I am working on resolving the issue, but in the
meantime, I'm disabling the legalization of scalar_to_vector operation for v2i64
and the associated testing until I can get this fixed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245481 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 19:04:47 +00:00
Alex Lorenz
baf422e9ec MIR Serialization: Serialize defined registers that require 'def' register flag.
The defined registers are already serialized - they are represented by placing
them before the '=' in a machine instruction. However, certain instructions like
INLINEASM can have defined register operands after the '=', so this commit
introduces the 'def' register flag for such operands.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245480 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 18:55:47 +00:00
Bruno Cardoso Lopes
71a40e6fef [PeepholeOptimizer] Look through PHIs to find additional register sources
Reintroduce r245442. Remove an overly conservative assertion introduced
in r245442. We could replace the assertion to use `shareSameRegisterFile`
instead, but in that point in `insertPHI` we already lost the original
Def subreg to check against. So drop the assertion completely.

Original commit message:

- Teaches the ValueTracker in the PeepholeOptimizer to look through PHI
instructions.
- Add findNextSourceAndRewritePHI method to lookup into multiple sources
returnted by the ValueTracker and rewrite PHIs with new sources.

With these changes we can find more register sources and rewrite more
copies to allow coaslescing of bitcast instructions. Hence, we eliminate
unnecessary VR64 <-> GR64 copies in x86, but it could be extended to
other archs by marking "isBitcast" on target specific instructions. The
x86 example follows:

A:
  psllq %mm1, %mm0
  movd  %mm0, %r9
  jmp C

B:
  por %mm1, %mm0
  movd  %mm0, %r9
  jmp C

C:
  movd  %r9, %mm0
  pshufw  $238, %mm0, %mm0

Becomes:

A:
  psllq %mm1, %mm0
  jmp C

B:
  por %mm1, %mm0
  jmp C

C:
  pshufw  $238, %mm0, %mm0

Differential Revision: http://reviews.llvm.org/D11197
rdar://problem/20404526

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245479 91177308-0d34-0410-b5e6-96231b3b80d8
2015-08-19 18:53:36 +00:00