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[X86][SSE] Bitcast assertion in XFormVExtractWithShuffleIntoLoad

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Minor patch to fix an issue in XFormVExtractWithShuffleIntoLoad where a load is unary shuffled, then bitcast (to a type with the same number of elements) before extracting an element.

An undef was created for the second shuffle operand using the original (post-bitcasted) vector type instead of the pre-bitcasted type like the rest of the shuffle node - this was then causing an assertion on the different types later on inside SelectionDAG::getVectorShuffle.

Differential Revision: http://reviews.llvm.org/D5917



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@220592 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Simon Pilgrim 2014-10-24 21:04:41 +00:00
parent 8699f5390b
commit 44efa200e2
2 changed files with 28 additions and 9 deletions
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21
lib/Target/X86/X86ISelLowering.cpp
View File

@ -21776,7 +21776,7 @@ static SDValue PerformTruncateCombine(SDNode *N, SelectionDAG &DAG,
/// XFormVExtractWithShuffleIntoLoad - Check if a vector extract from a target
/// specific shuffle of a load can be folded into a single element load.
/// Similar handling for VECTOR_SHUFFLE is performed by DAGCombiner, but
/// shuffles have been customed lowered so we need to handle those here.
/// shuffles have been custom lowered so we need to handle those here.
static SDValue XFormVExtractWithShuffleIntoLoad(SDNode *N, SelectionDAG &DAG,
TargetLowering::DAGCombinerInfo &DCI) {
if (DCI.isBeforeLegalizeOps())
@ -21788,18 +21788,20 @@ static SDValue XFormVExtractWithShuffleIntoLoad(SDNode *N, SelectionDAG &DAG,
if (!isa<ConstantSDNode>(EltNo))
return SDValue();
EVT VT = InVec.getValueType();
EVT OriginalVT = InVec.getValueType();
if (InVec.getOpcode() == ISD::BITCAST) {
// Don't duplicate a load with other uses.
if (!InVec.hasOneUse())
return SDValue();
EVT BCVT = InVec.getOperand(0).getValueType();
if (BCVT.getVectorNumElements() != VT.getVectorNumElements())
if (BCVT.getVectorNumElements() != OriginalVT.getVectorNumElements())
return SDValue();
InVec = InVec.getOperand(0);
}
EVT CurrentVT = InVec.getValueType();
if (!isTargetShuffle(InVec.getOpcode()))
return SDValue();
@ -21809,12 +21811,12 @@ static SDValue XFormVExtractWithShuffleIntoLoad(SDNode *N, SelectionDAG &DAG,
SmallVector<int, 16> ShuffleMask;
bool UnaryShuffle;
if (!getTargetShuffleMask(InVec.getNode(), VT.getSimpleVT(), ShuffleMask,
UnaryShuffle))
if (!getTargetShuffleMask(InVec.getNode(), CurrentVT.getSimpleVT(),
ShuffleMask, UnaryShuffle))
return SDValue();
// Select the input vector, guarding against out of range extract vector.
unsigned NumElems = VT.getVectorNumElements();
unsigned NumElems = CurrentVT.getVectorNumElements();
int Elt = cast<ConstantSDNode>(EltNo)->getZExtValue();
int Idx = (Elt > (int)NumElems) ? -1 : ShuffleMask[Elt];
SDValue LdNode = (Idx < (int)NumElems) ? InVec.getOperand(0)
@ -21856,11 +21858,12 @@ static SDValue XFormVExtractWithShuffleIntoLoad(SDNode *N, SelectionDAG &DAG,
SDLoc dl(N);
// Create shuffle node taking into account the case that its a unary shuffle
SDValue Shuffle = (UnaryShuffle) ? DAG.getUNDEF(VT) : InVec.getOperand(1);
Shuffle = DAG.getVectorShuffle(InVec.getValueType(), dl,
SDValue Shuffle = (UnaryShuffle) ? DAG.getUNDEF(CurrentVT)
: InVec.getOperand(1);
Shuffle = DAG.getVectorShuffle(CurrentVT, dl,
InVec.getOperand(0), Shuffle,
&ShuffleMask[0]);
Shuffle = DAG.getNode(ISD::BITCAST, dl, VT, Shuffle);
Shuffle = DAG.getNode(ISD::BITCAST, dl, OriginalVT, Shuffle);
return DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, N->getValueType(0), Shuffle,
EltNo);
}

16
test/CodeGen/X86/extractelement-load.ll
View File

@ -46,3 +46,19 @@ bb:
store double %.sroa.3.24.vec.extract, double* undef, align 8
unreachable
}
; Case where a load is unary shuffled, then bitcast (to a type with the same
; number of elements) before extractelement.
; This is testing for an assertion - the extraction was assuming that the undef
; second shuffle operand was a post-bitcast type instead of a pre-bitcast type.
define i64 @t4(<2 x double>* %a) {
; CHECK-LABEL: t4:
; CHECK: mov
; CHECK: ret
%b = load <2 x double>* %a, align 16
%c = shufflevector <2 x double> %b, <2 x double> %b, <2 x i32> <i32 1, i32 0>
%d = bitcast <2 x double> %c to <2 x i64>
%e = extractelement <2 x i64> %d, i32 1
ret i64 %e
}