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[X86][SSE] Fixed issue with commutation of 'faux unary' target shuffles (PR26667) 

Fixed a bug introduced by D16683 when a binary shuffle is simplified to a unary shuffle (with undef/zero sentinel mask indices) - if this resulted in only the second input being used combineX86ShuffleChain failed to take this into account and still referenced the first input.

llvm-svn: 261434
This commit is contained in:
Simon Pilgrim 2016-02-20 14:39:45 +00:00
parent ccf2cce67c
commit ecb0433599
2 changed files with 6 additions and 5 deletions
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9
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -23506,15 +23506,15 @@ static SDValue PerformShuffleCombine256(SDNode *N, SelectionDAG &DAG,
/// into either a single instruction if there is a special purpose instruction
/// for this operation, or into a PSHUFB instruction which is a fully general
/// instruction but should only be used to replace chains over a certain depth.
static bool combineX86ShuffleChain(SDValue Op, SDValue Root, ArrayRef<int> Mask,
int Depth, bool HasPSHUFB, SelectionDAG &DAG,
static bool combineX86ShuffleChain(SDValue Input, SDValue Root,
ArrayRef<int> Mask, int Depth,
bool HasPSHUFB, SelectionDAG &DAG,
TargetLowering::DAGCombinerInfo &DCI,
const X86Subtarget &Subtarget) {
assert(!Mask.empty() && "Cannot combine an empty shuffle mask!");
// Find the operand that enters the chain. Note that multiple uses are OK
// here, we're not going to remove the operand we find.
SDValue Input = Op.getOperand(0);
while (Input.getOpcode() == ISD::BITCAST)
Input = Input.getOperand(0);
@ -23814,7 +23814,6 @@ static bool combineX86ShufflesRecursively(SDValue Op, SDValue Root,
DAG, DCI, Subtarget))
return true;
// Minor canonicalization of the accumulated shuffle mask to make it easier
// to match below. All this does is detect masks with sequential pairs of
// elements, and shrink them to the half-width mask. It does this in a loop
@ -23826,7 +23825,7 @@ static bool combineX86ShufflesRecursively(SDValue Op, SDValue Root,
WidenedMask.clear();
}
return combineX86ShuffleChain(Op, Root, Mask, Depth, HasPSHUFB, DAG, DCI,
return combineX86ShuffleChain(Input0, Root, Mask, Depth, HasPSHUFB, DAG, DCI,
Subtarget);
}

2
llvm/test/CodeGen/X86/avx-intrinsics-fast-isel.ll
View File

@ -391,10 +391,12 @@ declare <4 x double> @llvm.x86.avx.vperm2f128.pd.256(<4 x double>, <4 x double>,
define <8 x float> @test_mm256_permute2f128_ps(<8 x float> %a0, <8 x float> %a1) {
; X32-LABEL: test_mm256_permute2f128_ps:
; X32: # BB#0:
; X32-NEXT: vmovaps %ymm1, %ymm0
; X32-NEXT: retl
;
; X64-LABEL: test_mm256_permute2f128_ps:
; X64: # BB#0:
; X64-NEXT: vmovaps %ymm1, %ymm0
; X64-NEXT: retq
%res = call <8 x float> @llvm.x86.avx.vperm2f128.ps.256(<8 x float> %a0, <8 x float> %a1, i8 50)
ret <8 x float> %res