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[SelectionDAG][NFC] Refactor duplicate code into SDNode::bitcastToAPInt() #127503

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Merged
merged 2 commits into from
Feb 20, 2025
Merged

[SelectionDAG][NFC] Refactor duplicate code into SDNode::bitcastToAPInt() #127503

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[SelectionDAG][NFC] Refactor duplicate code into SDNode::bitcastToAPI…
pfusik Feb 17, 2025
4b3731c
[RISCV] Apply a review suggestion
pfusik Feb 19, 2025
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10 changes: 10 additions & 0 deletions llvm/include/llvm/CodeGen/SelectionDAGNodes.h
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Original file line number Diff line number Diff line change
Expand Up @@ -989,6 +989,8 @@ END_TWO_BYTE_PACK()
/// Helper method returns the APInt value of a ConstantSDNode.
inline const APInt &getAsAPIntVal() const;

inline std::optional<APInt> bitcastToAPInt() const;

const SDValue &getOperand(unsigned Num) const {
assert(Num < NumOperands && "Invalid child # of SDNode!");
return OperandList[Num];
Expand Down Expand Up @@ -1785,6 +1787,14 @@ class ConstantFPSDNode : public SDNode {
}
};

std::optional<APInt> SDNode::bitcastToAPInt() const {
if (auto *CN = dyn_cast<ConstantSDNode>(this))
return CN->getAPIntValue();
if (auto *CFPN = dyn_cast<ConstantFPSDNode>(this))
return CFPN->getValueAPF().bitcastToAPInt();
return std::nullopt;
}

/// Returns true if \p V is a constant integer zero.
bool isNullConstant(SDValue V);

Expand Down
6 changes: 2 additions & 4 deletions llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
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Expand Up @@ -27420,10 +27420,8 @@ SDValue DAGCombiner::XformToShuffleWithZero(SDNode *N) {
}

APInt Bits;
if (auto *Cst = dyn_cast<ConstantSDNode>(Elt))
Bits = Cst->getAPIntValue();
else if (auto *CstFP = dyn_cast<ConstantFPSDNode>(Elt))
Bits = CstFP->getValueAPF().bitcastToAPInt();
if (auto OptBits = Elt->bitcastToAPInt())
Bits = *std::move(OptBits);
else
return SDValue();
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@arsenm arsenm Feb 17, 2025

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Avoid the move and should invert this to early return on failure

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@pfusik pfusik Feb 17, 2025

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Do you mean:

auto OptBits = Elt->bitcastToAPInt();
if (!OptBits)
  return SDValue();
APInt Bits = *OptBits;

?

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@arsenm arsenm Feb 19, 2025

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Yes. I'd do

  std::optional<APInt> Bits = Elt->bitcastToAPInt();
  if (!Bits)
    return SDValue();
  // Use *Bits

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@pfusik pfusik Feb 19, 2025

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Done


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38 changes: 12 additions & 26 deletions llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -152,14 +152,10 @@ bool ConstantFPSDNode::isValueValidForType(EVT VT,

bool ISD::isConstantSplatVector(const SDNode *N, APInt &SplatVal) {
if (N->getOpcode() == ISD::SPLAT_VECTOR) {
unsigned EltSize =
N->getValueType(0).getVectorElementType().getSizeInBits();
if (auto *Op0 = dyn_cast<ConstantSDNode>(N->getOperand(0))) {
SplatVal = Op0->getAPIntValue().trunc(EltSize);
return true;
}
if (auto *Op0 = dyn_cast<ConstantFPSDNode>(N->getOperand(0))) {
SplatVal = Op0->getValueAPF().bitcastToAPInt().trunc(EltSize);
if (auto OptAPInt = N->getOperand(0)->bitcastToAPInt()) {
unsigned EltSize =
N->getValueType(0).getVectorElementType().getSizeInBits();
SplatVal = OptAPInt->trunc(EltSize);
return true;
}
}
Expand Down Expand Up @@ -215,12 +211,9 @@ bool ISD::isConstantSplatVectorAllOnes(const SDNode *N, bool BuildVectorOnly) {
// we care if the resultant vector is all ones, not whether the individual
// constants are.
SDValue NotZero = N->getOperand(i);
unsigned EltSize = N->getValueType(0).getScalarSizeInBits();
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(NotZero)) {
if (CN->getAPIntValue().countr_one() < EltSize)
return false;
} else if (ConstantFPSDNode *CFPN = dyn_cast<ConstantFPSDNode>(NotZero)) {
if (CFPN->getValueAPF().bitcastToAPInt().countr_one() < EltSize)
if (auto OptAPInt = NotZero->bitcastToAPInt()) {
unsigned EltSize = N->getValueType(0).getScalarSizeInBits();
if (OptAPInt->countr_one() < EltSize)
return false;
} else
return false;
Expand Down Expand Up @@ -259,12 +252,9 @@ bool ISD::isConstantSplatVectorAllZeros(const SDNode *N, bool BuildVectorOnly) {
// We only want to check enough bits to cover the vector elements, because
// we care if the resultant vector is all zeros, not whether the individual
// constants are.
unsigned EltSize = N->getValueType(0).getScalarSizeInBits();
if (ConstantSDNode *CN = dyn_cast<ConstantSDNode>(Op)) {
if (CN->getAPIntValue().countr_zero() < EltSize)
return false;
} else if (ConstantFPSDNode *CFPN = dyn_cast<ConstantFPSDNode>(Op)) {
if (CFPN->getValueAPF().bitcastToAPInt().countr_zero() < EltSize)
if (auto OptAPInt = Op->bitcastToAPInt()) {
unsigned EltSize = N->getValueType(0).getScalarSizeInBits();
if (OptAPInt->countr_zero() < EltSize)
return false;
} else
return false;
Expand Down Expand Up @@ -3434,13 +3424,9 @@ KnownBits SelectionDAG::computeKnownBits(SDValue Op, const APInt &DemandedElts,

KnownBits Known(BitWidth); // Don't know anything.

if (auto *C = dyn_cast<ConstantSDNode>(Op)) {
if (auto OptAPInt = Op->bitcastToAPInt()) {
// We know all of the bits for a constant!
return KnownBits::makeConstant(C->getAPIntValue());
}
if (auto *C = dyn_cast<ConstantFPSDNode>(Op)) {
// We know all of the bits for a constant fp!
return KnownBits::makeConstant(C->getValueAPF().bitcastToAPInt());
return KnownBits::makeConstant(*std::move(OptAPInt));
}

if (Depth >= MaxRecursionDepth)
Expand Down
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