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[RISCV][TTI] Refine the cost of FCmp #88833

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Merged
merged 4 commits into from
Apr 18, 2024
Merged

[RISCV][TTI] Refine the cost of FCmp #88833

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0fbccc8
[RISCV][TTI] Refine the cost of FCmp
arcbbb Apr 16, 2024
392697e
Address comments
arcbbb Apr 16, 2024
f2c1a5f
Split vfhmin support into a separate commit
arcbbb Apr 17, 2024
af48b54
Add fcmp true/false tests and missing VMXOR_MM & VMANDN_MM
arcbbb Apr 17, 2024
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48 changes: 38 additions & 10 deletions llvm/lib/Target/RISCV/RISCVTargetTransformInfo.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,10 @@ RISCVTTIImpl::getRISCVInstructionCost(ArrayRef<unsigned> OpCodes, MVT VT,
case RISCV::VMV_S_X:
case RISCV::VFMV_F_S:
case RISCV::VFMV_S_F:
case RISCV::VMOR_MM:
case RISCV::VMXOR_MM:
case RISCV::VMAND_MM:
case RISCV::VMANDN_MM:
case RISCV::VMNAND_MM:
case RISCV::VCPOP_M:
Cost += 1;
Expand Down Expand Up @@ -1383,7 +1387,13 @@ InstructionCost RISCVTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
getRISCVInstructionCost(RISCV::VMSLT_VV, LT.second, CostKind);
}

if ((Opcode == Instruction::FCmp) && ValTy->isVectorTy()) {
if ((Opcode == Instruction::FCmp) && ValTy->isVectorTy() &&
CmpInst::isFPPredicate(VecPred)) {

// Use VMXOR_MM and VMXNOR_MM to generate all true/false mask
if ((VecPred == CmpInst::FCMP_FALSE) || (VecPred == CmpInst::FCMP_TRUE))
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Do we have tests for this? I didn't see a true/false conditions in rvv-cmp.ll

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My mistake, I forgot to include this. Thanks!

return getRISCVInstructionCost(RISCV::VMXOR_MM, LT.second, CostKind);

// If we do not support the input floating point vector type, use the base
// one which will calculate as:
// ScalarizeCost + Num * Cost for fixed vector,
Expand All @@ -1393,16 +1403,34 @@ InstructionCost RISCVTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
(ValTy->getScalarSizeInBits() == 64 && !ST->hasVInstructionsF64()))
return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
I);

// Assuming vector fp compare and mask instructions are all the same cost
// until a need arises to differentiate them.
switch (VecPred) {
// Support natively.
case CmpInst::FCMP_OEQ:
case CmpInst::FCMP_OGT:
case CmpInst::FCMP_OGE:
case CmpInst::FCMP_OLT:
case CmpInst::FCMP_OLE:
case CmpInst::FCMP_UNE:
return LT.first * 1;
// TODO: Other comparisons?
case CmpInst::FCMP_ONE: // vmflt.vv + vmflt.vv + vmor.mm
case CmpInst::FCMP_ORD: // vmfeq.vv + vmfeq.vv + vmand.mm
case CmpInst::FCMP_UNO: // vmfne.vv + vmfne.vv + vmor.mm
case CmpInst::FCMP_UEQ: // vmflt.vv + vmflt.vv + vmnor.mm
return LT.first * getRISCVInstructionCost(
{RISCV::VMFLT_VV, RISCV::VMFLT_VV, RISCV::VMOR_MM},
LT.second, CostKind);

case CmpInst::FCMP_UGT: // vmfle.vv + vmnot.m
case CmpInst::FCMP_UGE: // vmflt.vv + vmnot.m
case CmpInst::FCMP_ULT: // vmfle.vv + vmnot.m
case CmpInst::FCMP_ULE: // vmflt.vv + vmnot.m
return LT.first *
getRISCVInstructionCost({RISCV::VMFLT_VV, RISCV::VMNAND_MM},
LT.second, CostKind);

case CmpInst::FCMP_OEQ: // vmfeq.vv
case CmpInst::FCMP_OGT: // vmflt.vv
case CmpInst::FCMP_OGE: // vmfle.vv
case CmpInst::FCMP_OLT: // vmflt.vv
case CmpInst::FCMP_OLE: // vmfle.vv
case CmpInst::FCMP_UNE: // vmfne.vv
return LT.first *
getRISCVInstructionCost(RISCV::VMFLT_VV, LT.second, CostKind);
default:
break;
}
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