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[X86] Don't count the chain uses when forming broadcast loads in lowerBuildVectorAsBroadcast. 

The build_vector needs to be the only user of the data, but the
chain will likely have another use. So we can't make sure the
build_vector is the only user of the node.
This commit is contained in:
Craig Topper 2020-03-02 22:28:43 -08:00
parent 383e3ec1b2
commit 68aeaab888
2 changed files with 8 additions and 5 deletions
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10
llvm/lib/Target/X86/X86ISelLowering.cpp
View File

@ -8621,10 +8621,12 @@ static SDValue lowerBuildVectorAsBroadcast(BuildVectorSDNode *BVOp,
bool ConstSplatVal =
(Ld.getOpcode() == ISD::Constant || Ld.getOpcode() == ISD::ConstantFP);
bool IsLoad = ISD::isNormalLoad(Ld.getNode());
// Make sure that all of the users of a non-constant load are from the
// BUILD_VECTOR node.
if (!ConstSplatVal && !BVOp->isOnlyUserOf(Ld.getNode()))
// FIXME: Is the use count needed for non-constant, non-load case?
if (!ConstSplatVal && !IsLoad && !BVOp->isOnlyUserOf(Ld.getNode()))
return SDValue();
unsigned ScalarSize = Ld.getValueSizeInBits();
@ -8674,8 +8676,6 @@ static SDValue lowerBuildVectorAsBroadcast(BuildVectorSDNode *BVOp,
}
}
bool IsLoad = ISD::isNormalLoad(Ld.getNode());
// Handle AVX2 in-register broadcasts.
if (!IsLoad && Subtarget.hasInt256() &&
(ScalarSize == 32 || (IsGE256 && ScalarSize == 64)))
@ -8685,6 +8685,10 @@ static SDValue lowerBuildVectorAsBroadcast(BuildVectorSDNode *BVOp,
if (!IsLoad)
return SDValue();
// Make sure the non-chain result is only used by this build vector.
if (!Ld->hasNUsesOfValue(NumElts - NumUndefElts, 0))
return SDValue();
if (ScalarSize == 32 || (IsGE256 && ScalarSize == 64) ||
(Subtarget.hasVLX() && ScalarSize == 64))
return DAG.getNode(X86ISD::VBROADCAST, dl, VT, Ld);

3
llvm/test/CodeGen/X86/pr35443.ll
View File

@ -8,8 +8,7 @@
define void @pr35443() {
; CHECK-LABEL: pr35443:
; CHECK: # %bb.0: # %entry
; CHECK-NEXT: movzbl ac+{{.*}}(%rip), %eax
; CHECK-NEXT: vmovd %eax, %xmm0
; CHECK-NEXT: vpbroadcastb ac+{{.*}}(%rip), %xmm0
; CHECK-NEXT: vpmovzxbq {{.*#+}} ymm0 = xmm0[0],zero,zero,zero,zero,zero,zero,zero,xmm0[1],zero,zero,zero,zero,zero,zero,zero,xmm0[2],zero,zero,zero,zero,zero,zero,zero,xmm0[3],zero,zero,zero,zero,zero,zero,zero
; CHECK-NEXT: vpxor %xmm1, %xmm1, %xmm1
; CHECK-NEXT: vpsubq %ymm0, %ymm1, %ymm0