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[X86] Add verifyTargetSDNode for x86 target specific nodes #123589

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[X86] Add verifyTargetSDNode for x86 target specific nodes #123589

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28 changes: 28 additions & 0 deletions llvm/lib/Target/X86/X86ISelLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -61009,3 +61009,31 @@ Align X86TargetLowering::getPrefLoopAlignment(MachineLoop *ML) const {
return Align(1ULL << ExperimentalPrefInnermostLoopAlignment);
return TargetLowering::getPrefLoopAlignment();
}

#ifndef NDEBUG
void X86TargetLowering::verifyTargetSDNode(const SDNode *N) const {
switch (N->getOpcode()) {
default:
break;
case X86ISD::KSHIFTL:
case X86ISD::KSHIFTR: {
EVT VT = N->getValueType(0);
auto *Amt = cast<ConstantSDNode>(N->getOperand(1));
assert(Amt->getAPIntValue().ult(VT.getVectorNumElements()) &&
"Out of range KSHIFT shift amount");
break;
}
case X86ISD::PSADBW: {
EVT VT = N->getValueType(0);
SDValue LHS = N->getOperand(0);
SDValue RHS = N->getOperand(1);
assert((VT == MVT::v2i64 || VT == MVT::v4i64 || VT == MVT::v8i64) &&
LHS.getValueType() == RHS.getValueType() &&
LHS.getValueSizeInBits() == VT.getSizeInBits() &&
LHS.getValueType().getScalarType() == MVT::i8 &&
Comment on lines +61030 to +61033
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We have defined the node with
SDTCVecEltisVT<0, i64>, SDTCVecEltisVT<1, i8> and SDTCisSameAs<1,2>.
Do we still need these check here?

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That would only check at selection - it'd be nice to be able to auto generate these checks for verifyTargetSDNode but it'd be a rather large job.

What I'm finding is that verifyTargetSDNode is fantastic for tracing problems, especially during debugging, as its called as part of getNode() - so the assertion occurs in the code stack where the node is created - we have some similar asserts in the node combines / known bits etc. but working out where the node came from isn't always straightforward (or requires trawling through logs).

I'm tempted to remove the equivalent asserts from other locations as verifyTargetSDNode should have caught most cases.

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it'd be nice to be able to auto generate these checks for verifyTargetSDNode but it'd be a rather large job.

FYI I'm doing that in #119709.
Although as-is it doesn't catch everything yet.

"Unexpected PSADBW types");
break;
}
}
}
#endif
4 changes: 4 additions & 0 deletions llvm/lib/Target/X86/X86ISelLowering.h
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Expand Up @@ -1658,6 +1658,10 @@ namespace llvm {
return TargetLoweringBase::getTypeToTransformTo(Context, VT);
}

#ifndef NDEBUG
void verifyTargetSDNode(const SDNode *N) const override;
#endif

protected:
std::pair<const TargetRegisterClass *, uint8_t>
findRepresentativeClass(const TargetRegisterInfo *TRI,
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