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[RISCV] Add cost modelling for vector widenning reduction. 

In RVV, we use vwredsum.vs and vwredsumu.vs for vecreduce.add(ext(Ty A)) if the result type's width is twice of the input vector's SEW-width. In this situation, the cost of extended add reduction should be same as single-width add reduction. So as the vector float widenning reduction.

Differential Revision: https://reviews.llvm.org/D129994
This commit is contained in:
jacquesguan 2022-07-18 17:37:37 +08:00
parent 6f867f9102
commit b61cfc91ea
2 changed files with 31 additions and 0 deletions
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26
llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
View File

@ -377,6 +377,32 @@ RISCVTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *Ty,
return (LT.first - 1) + BaseCost + Log2_32_Ceil(VL);
}
InstructionCost RISCVTTIImpl::getExtendedReductionCost(
unsigned Opcode, bool IsUnsigned, Type *ResTy, VectorType *ValTy,
Optional<FastMathFlags> FMF, TTI::TargetCostKind CostKind) {
if (isa<FixedVectorType>(ValTy) && !ST->useRVVForFixedLengthVectors())
return BaseT::getExtendedReductionCost(Opcode, IsUnsigned, ResTy, ValTy,
FMF, CostKind);
// Skip if scalar size of ResTy is bigger than ELEN.
if (ResTy->getScalarSizeInBits() > ST->getELEN())
return BaseT::getExtendedReductionCost(Opcode, IsUnsigned, ResTy, ValTy,
FMF, CostKind);
if (Opcode != Instruction::Add && Opcode != Instruction::FAdd)
return BaseT::getExtendedReductionCost(Opcode, IsUnsigned, ResTy, ValTy,
FMF, CostKind);
std::pair<InstructionCost, MVT> LT = TLI->getTypeLegalizationCost(DL, ValTy);
if (ResTy->getScalarSizeInBits() != 2 * LT.second.getScalarSizeInBits())
return BaseT::getExtendedReductionCost(Opcode, IsUnsigned, ResTy, ValTy,
FMF, CostKind);
return (LT.first - 1) +
getArithmeticReductionCost(Opcode, ValTy, FMF, CostKind);
}
void RISCVTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
TTI::UnrollingPreferences &UP,
OptimizationRemarkEmitter *ORE) {

5
llvm/lib/Target/RISCV/RISCVTargetTransformInfo.h
View File

@ -112,6 +112,11 @@ public:
Optional<FastMathFlags> FMF,
TTI::TargetCostKind CostKind);
InstructionCost getExtendedReductionCost(unsigned Opcode, bool IsUnsigned,
Type *ResTy, VectorType *ValTy,
Optional<FastMathFlags> FMF,
TTI::TargetCostKind CostKind);
bool isElementTypeLegalForScalableVector(Type *Ty) const {
return TLI->isLegalElementTypeForRVV(Ty);
}