Target/RISCV/RISCVTargetTransformInfo.cpp

//===-- RISCVTargetTransformInfo.cpp - RISC-V specific TTI ----------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "RISCVTargetTransformInfo.h"
#include "MCTargetDesc/RISCVMatInt.h"
#include "llvm/ADT/STLExtras.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/CodeGen/CostTable.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/IR/Instructions.h"
#include <cmath>
#include <optional>
using namespace llvm;

#define DEBUG_TYPE "riscvtti"

static cl::opt<unsigned> RVVRegisterWidthLMUL(
    "riscv-v-register-bit-width-lmul",
    cl::desc(
        "The LMUL to use for getRegisterBitWidth queries. Affects LMUL used "
        "by autovectorized code. Fractional LMULs are not supported."),
    cl::init(2), cl::Hidden);

static cl::opt<unsigned> SLPMaxVF(
    "riscv-v-slp-max-vf",
    cl::desc(
        "Overrides result used for getMaximumVF query which is used "
        "exclusively by SLP vectorizer."),
    cl::Hidden);

InstructionCost
RISCVTTIImpl::getRISCVInstructionCost(ArrayRef<unsigned> OpCodes, MVT VT,
                                      TTI::TargetCostKind CostKind) {
  size_t NumInstr = OpCodes.size();
  if (CostKind == TTI::TCK_CodeSize)
    return NumInstr;
  InstructionCost LMULCost = TLI->getLMULCost(VT);
  if ((CostKind != TTI::TCK_RecipThroughput) && (CostKind != TTI::TCK_Latency))
    return LMULCost * NumInstr;
  InstructionCost Cost = 0;
  for (auto Op : OpCodes) {
    switch (Op) {
    case RISCV::VRGATHER_VI:
      Cost += TLI->getVRGatherVICost(VT);
      break;
    case RISCV::VRGATHER_VV:
      Cost += TLI->getVRGatherVVCost(VT);
      break;
    case RISCV::VSLIDEUP_VI:
    case RISCV::VSLIDEDOWN_VI:
      Cost += TLI->getVSlideVICost(VT);
      break;
    case RISCV::VSLIDEUP_VX:
    case RISCV::VSLIDEDOWN_VX:
      Cost += TLI->getVSlideVXCost(VT);
      break;
    case RISCV::VREDMAX_VS:
    case RISCV::VREDMIN_VS:
    case RISCV::VREDMAXU_VS:
    case RISCV::VREDMINU_VS:
    case RISCV::VREDSUM_VS:
    case RISCV::VREDAND_VS:
    case RISCV::VREDOR_VS:
    case RISCV::VREDXOR_VS:
    case RISCV::VFREDMAX_VS:
    case RISCV::VFREDMIN_VS:
    case RISCV::VFREDUSUM_VS: {
      unsigned VL = VT.getVectorMinNumElements();
      if (!VT.isFixedLengthVector())
        VL *= *getVScaleForTuning();
      Cost += Log2_32_Ceil(VL);
      break;
    }
    case RISCV::VFREDOSUM_VS: {
      unsigned VL = VT.getVectorMinNumElements();
      if (!VT.isFixedLengthVector())
        VL *= *getVScaleForTuning();
      Cost += VL;
      break;
    }
    case RISCV::VMV_X_S:
    case RISCV::VMV_S_X:
      Cost += 1;
      break;
    default:
      Cost += LMULCost;
    }
  }
  return Cost;
}

InstructionCost RISCVTTIImpl::getIntImmCost(const APInt &Imm, Type *Ty,
                                            TTI::TargetCostKind CostKind) {
  assert(Ty->isIntegerTy() &&
         "getIntImmCost can only estimate cost of materialising integers");

  // We have a Zero register, so 0 is always free.
  if (Imm == 0)
    return TTI::TCC_Free;

  // Otherwise, we check how many instructions it will take to materialise.
  const DataLayout &DL = getDataLayout();
  return RISCVMatInt::getIntMatCost(Imm, DL.getTypeSizeInBits(Ty), *getST());
}

// Look for patterns of shift followed by AND that can be turned into a pair of
// shifts. We won't need to materialize an immediate for the AND so these can
// be considered free.
static bool canUseShiftPair(Instruction *Inst, const APInt &Imm) {
  uint64_t Mask = Imm.getZExtValue();
  auto *BO = dyn_cast<BinaryOperator>(Inst->getOperand(0));
  if (!BO || !BO->hasOneUse())
    return false;

  if (BO->getOpcode() != Instruction::Shl)
    return false;

  if (!isa<ConstantInt>(BO->getOperand(1)))
    return false;

  unsigned ShAmt = cast<ConstantInt>(BO->getOperand(1))->getZExtValue();
  // (and (shl x, c2), c1) will be matched to (srli (slli x, c2+c3), c3) if c1
  // is a mask shifted by c2 bits with c3 leading zeros.
  if (isShiftedMask_64(Mask)) {
    unsigned Trailing = llvm::countr_zero(Mask);
    if (ShAmt == Trailing)
      return true;
  }

  return false;
}

InstructionCost RISCVTTIImpl::getIntImmCostInst(unsigned Opcode, unsigned Idx,
                                                const APInt &Imm, Type *Ty,
                                                TTI::TargetCostKind CostKind,
                                                Instruction *Inst) {
  assert(Ty->isIntegerTy() &&
         "getIntImmCost can only estimate cost of materialising integers");

  // We have a Zero register, so 0 is always free.
  if (Imm == 0)
    return TTI::TCC_Free;

  // Some instructions in RISC-V can take a 12-bit immediate. Some of these are
  // commutative, in others the immediate comes from a specific argument index.
  bool Takes12BitImm = false;
  unsigned ImmArgIdx = ~0U;

  switch (Opcode) {
  case Instruction::GetElementPtr:
    // Never hoist any arguments to a GetElementPtr. CodeGenPrepare will
    // split up large offsets in GEP into better parts than ConstantHoisting
    // can.
    return TTI::TCC_Free;
  case Instruction::And:
    // zext.h
    if (Imm == UINT64_C(0xffff) && ST->hasStdExtZbb())
      return TTI::TCC_Free;
    // zext.w
    if (Imm == UINT64_C(0xffffffff) && ST->hasStdExtZba())
      return TTI::TCC_Free;
    // bclri
    if (ST->hasStdExtZbs() && (~Imm).isPowerOf2())
      return TTI::TCC_Free;
    if (Inst && Idx == 1 && Imm.getBitWidth() <= ST->getXLen() &&
        canUseShiftPair(Inst, Imm))
      return TTI::TCC_Free;
    Takes12BitImm = true;
    break;
  case Instruction::Add:
    Takes12BitImm = true;
    break;
  case Instruction::Or:
  case Instruction::Xor:
    // bseti/binvi
    if (ST->hasStdExtZbs() && Imm.isPowerOf2())
      return TTI::TCC_Free;
    Takes12BitImm = true;
    break;
  case Instruction::Mul:
    // Power of 2 is a shift. Negated power of 2 is a shift and a negate.
    if (Imm.isPowerOf2() || Imm.isNegatedPowerOf2())
      return TTI::TCC_Free;
    // One more or less than a power of 2 can use SLLI+ADD/SUB.
    if ((Imm + 1).isPowerOf2() || (Imm - 1).isPowerOf2())
      return TTI::TCC_Free;
    // FIXME: There is no MULI instruction.
    Takes12BitImm = true;
    break;
  case Instruction::Sub:
  case Instruction::Shl:
  case Instruction::LShr:
  case Instruction::AShr:
    Takes12BitImm = true;
    ImmArgIdx = 1;
    break;
  default:
    break;
  }

  if (Takes12BitImm) {
    // Check immediate is the correct argument...
    if (Instruction::isCommutative(Opcode) || Idx == ImmArgIdx) {
      // ... and fits into the 12-bit immediate.
      if (Imm.getSignificantBits() <= 64 &&
          getTLI()->isLegalAddImmediate(Imm.getSExtValue())) {
        return TTI::TCC_Free;
      }
    }

    // Otherwise, use the full materialisation cost.
    return getIntImmCost(Imm, Ty, CostKind);
  }

  // By default, prevent hoisting.
  return TTI::TCC_Free;
}

InstructionCost
RISCVTTIImpl::getIntImmCostIntrin(Intrinsic::ID IID, unsigned Idx,
                                  const APInt &Imm, Type *Ty,
                                  TTI::TargetCostKind CostKind) {
  // Prevent hoisting in unknown cases.
  return TTI::TCC_Free;
}

TargetTransformInfo::PopcntSupportKind
RISCVTTIImpl::getPopcntSupport(unsigned TyWidth) {
  assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
  return ST->hasStdExtZbb() || ST->hasVendorXCVbitmanip()
             ? TTI::PSK_FastHardware
             : TTI::PSK_Software;
}

bool RISCVTTIImpl::shouldExpandReduction(const IntrinsicInst *II) const {
  // Currently, the ExpandReductions pass can't expand scalable-vector
  // reductions, but we still request expansion as RVV doesn't support certain
  // reductions and the SelectionDAG can't legalize them either.
  switch (II->getIntrinsicID()) {
  default:
    return false;
  // These reductions have no equivalent in RVV
  case Intrinsic::vector_reduce_mul:
  case Intrinsic::vector_reduce_fmul:
    return true;
  }
}

std::optional<unsigned> RISCVTTIImpl::getMaxVScale() const {
  if (ST->hasVInstructions())
    return ST->getRealMaxVLen() / RISCV::RVVBitsPerBlock;
  return BaseT::getMaxVScale();
}

std::optional<unsigned> RISCVTTIImpl::getVScaleForTuning() const {
  if (ST->hasVInstructions())
    if (unsigned MinVLen = ST->getRealMinVLen();
        MinVLen >= RISCV::RVVBitsPerBlock)
      return MinVLen / RISCV::RVVBitsPerBlock;
  return BaseT::getVScaleForTuning();
}

TypeSize
RISCVTTIImpl::getRegisterBitWidth(TargetTransformInfo::RegisterKind K) const {
  unsigned LMUL =
      llvm::bit_floor(std::clamp<unsigned>(RVVRegisterWidthLMUL, 1, 8));
  switch (K) {
  case TargetTransformInfo::RGK_Scalar:
    return TypeSize::getFixed(ST->getXLen());
  case TargetTransformInfo::RGK_FixedWidthVector:
    return TypeSize::getFixed(
        ST->useRVVForFixedLengthVectors() ? LMUL * ST->getRealMinVLen() : 0);
  case TargetTransformInfo::RGK_ScalableVector:
    return TypeSize::getScalable(
        (ST->hasVInstructions() &&
         ST->getRealMinVLen() >= RISCV::RVVBitsPerBlock)
            ? LMUL * RISCV::RVVBitsPerBlock
            : 0);
  }

  llvm_unreachable("Unsupported register kind");
}

InstructionCost
RISCVTTIImpl::getConstantPoolLoadCost(Type *Ty,  TTI::TargetCostKind CostKind) {
  // Add a cost of address generation + the cost of the load. The address
  // is expected to be a PC relative offset to a constant pool entry
  // using auipc/addi.
  return 2 + getMemoryOpCost(Instruction::Load, Ty, DL.getABITypeAlign(Ty),
                             /*AddressSpace=*/0, CostKind);
}

static VectorType *getVRGatherIndexType(MVT DataVT, const RISCVSubtarget &ST,
                                        LLVMContext &C) {
  assert((DataVT.getScalarSizeInBits() != 8 ||
          DataVT.getVectorNumElements() <= 256) && "unhandled case in lowering");
  MVT IndexVT = DataVT.changeTypeToInteger();
  if (IndexVT.getScalarType().bitsGT(ST.getXLenVT()))
    IndexVT = IndexVT.changeVectorElementType(MVT::i16);
  return cast<VectorType>(EVT(IndexVT).getTypeForEVT(C));
}

InstructionCost RISCVTTIImpl::getShuffleCost(TTI::ShuffleKind Kind,
                                             VectorType *Tp, ArrayRef<int> Mask,
                                             TTI::TargetCostKind CostKind,
                                             int Index, VectorType *SubTp,
                                             ArrayRef<const Value *> Args) {
  Kind = improveShuffleKindFromMask(Kind, Mask, Tp, Index, SubTp);

  std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Tp);

  // First, handle cases where having a fixed length vector enables us to
  // give a more accurate cost than falling back to generic scalable codegen.
  // TODO: Each of these cases hints at a modeling gap around scalable vectors.
  if (isa<FixedVectorType>(Tp)) {
    switch (Kind) {
    default:
      break;
    case TTI::SK_PermuteSingleSrc: {
      if (Mask.size() >= 2 && LT.second.isFixedLengthVector()) {
        MVT EltTp = LT.second.getVectorElementType();
        // If the size of the element is < ELEN then shuffles of interleaves and
        // deinterleaves of 2 vectors can be lowered into the following
        // sequences
        if (EltTp.getScalarSizeInBits() < ST->getELen()) {
          // Example sequence:
          //   vsetivli     zero, 4, e8, mf4, ta, ma (ignored)
          //   vwaddu.vv    v10, v8, v9
          //   li       a0, -1                   (ignored)
          //   vwmaccu.vx   v10, a0, v9
          if (ShuffleVectorInst::isInterleaveMask(Mask, 2, Mask.size()))
            return 2 * LT.first * TLI->getLMULCost(LT.second);

          if (Mask[0] == 0 || Mask[0] == 1) {
            auto DeinterleaveMask = createStrideMask(Mask[0], 2, Mask.size());
            // Example sequence:
            //   vnsrl.wi   v10, v8, 0
            if (equal(DeinterleaveMask, Mask))
              return LT.first * getRISCVInstructionCost(RISCV::VNSRL_WI,
                                                        LT.second, CostKind);
          }
        }
      }
      // vrgather + cost of generating the mask constant.
      // We model this for an unknown mask with a single vrgather.
      if (LT.second.isFixedLengthVector() && LT.first == 1 &&
          (LT.second.getScalarSizeInBits() != 8 ||
           LT.second.getVectorNumElements() <= 256)) {
        VectorType *IdxTy = getVRGatherIndexType(LT.second, *ST, Tp->getContext());
        InstructionCost IndexCost = getConstantPoolLoadCost(IdxTy, CostKind);
        return IndexCost +
               getRISCVInstructionCost(RISCV::VRGATHER_VV, LT.second, CostKind);
      }
      [[fallthrough]];
    }
    case TTI::SK_Transpose:
    case TTI::SK_PermuteTwoSrc: {
      // 2 x (vrgather + cost of generating the mask constant) + cost of mask
      // register for the second vrgather. We model this for an unknown
      // (shuffle) mask.
      if (LT.second.isFixedLengthVector() && LT.first == 1 &&
          (LT.second.getScalarSizeInBits() != 8 ||
           LT.second.getVectorNumElements() <= 256)) {
        auto &C = Tp->getContext();
        auto EC = Tp->getElementCount();
        VectorType *IdxTy = getVRGatherIndexType(LT.second, *ST, C);
        VectorType *MaskTy = VectorType::get(IntegerType::getInt1Ty(C), EC);
        InstructionCost IndexCost = getConstantPoolLoadCost(IdxTy, CostKind);
        InstructionCost MaskCost = getConstantPoolLoadCost(MaskTy, CostKind);
        return 2 * IndexCost +
               getRISCVInstructionCost({RISCV::VRGATHER_VV, RISCV::VRGATHER_VV},
                                       LT.second, CostKind) +
               MaskCost;
      }
      [[fallthrough]];
    }
    case TTI::SK_Select: {
      // We are going to permute multiple sources and the result will be in
      // multiple destinations. Providing an accurate cost only for splits where
      // the element type remains the same.
      if (!Mask.empty() && LT.first.isValid() && LT.first != 1 &&
          LT.second.isFixedLengthVector() &&
          LT.second.getVectorElementType().getSizeInBits() ==
              Tp->getElementType()->getPrimitiveSizeInBits() &&
          LT.second.getVectorNumElements() <
              cast<FixedVectorType>(Tp)->getNumElements() &&
          divideCeil(Mask.size(),
                     cast<FixedVectorType>(Tp)->getNumElements()) ==
              static_cast<unsigned>(*LT.first.getValue())) {
        unsigned NumRegs = *LT.first.getValue();
        unsigned VF = cast<FixedVectorType>(Tp)->getNumElements();
        unsigned SubVF = PowerOf2Ceil(VF / NumRegs);
        auto *SubVecTy = FixedVectorType::get(Tp->getElementType(), SubVF);

        InstructionCost Cost = 0;
        for (unsigned I = 0; I < NumRegs; ++I) {
          bool IsSingleVector = true;
          SmallVector<int> SubMask(SubVF, PoisonMaskElem);
          transform(Mask.slice(I * SubVF,
                               I == NumRegs - 1 ? Mask.size() % SubVF : SubVF),
                    SubMask.begin(), [&](int I) {
                      bool SingleSubVector = I / VF == 0;
                      IsSingleVector &= SingleSubVector;
                      return (SingleSubVector ? 0 : 1) * SubVF + I % VF;
                    });
          Cost += getShuffleCost(IsSingleVector ? TTI::SK_PermuteSingleSrc
                                                : TTI::SK_PermuteTwoSrc,
                                 SubVecTy, SubMask, CostKind, 0, nullptr);
          return Cost;
        }
      }
      break;
    }
    }
  };

  // Handle scalable vectors (and fixed vectors legalized to scalable vectors).
  switch (Kind) {
  default:
    // Fallthrough to generic handling.
    // TODO: Most of these cases will return getInvalid in generic code, and
    // must be implemented here.
    break;
  case TTI::SK_ExtractSubvector:
    // Example sequence:
    // vsetivli     zero, 4, e8, mf2, tu, ma (ignored)
    // vslidedown.vi  v8, v9, 2
    return LT.first *
           getRISCVInstructionCost(RISCV::VSLIDEDOWN_VI, LT.second, CostKind);
  case TTI::SK_InsertSubvector:
    // Example sequence:
    // vsetivli     zero, 4, e8, mf2, tu, ma (ignored)
    // vslideup.vi  v8, v9, 2
    return LT.first *
           getRISCVInstructionCost(RISCV::VSLIDEUP_VI, LT.second, CostKind);
  case TTI::SK_Select: {
    // Example sequence:
    // li           a0, 90
    // vsetivli     zero, 8, e8, mf2, ta, ma (ignored)
    // vmv.s.x      v0, a0
    // vmerge.vvm   v8, v9, v8, v0
    // We use 2 for the cost of the mask materialization as this is the true
    // cost for small masks and most shuffles are small.  At worst, this cost
    // should be a very small constant for the constant pool load.  As such,
    // we may bias towards large selects slightly more than truely warranted.
    return LT.first *
           (1 + getRISCVInstructionCost({RISCV::VMV_S_X, RISCV::VMERGE_VVM},
                                        LT.second, CostKind));
  }
  case TTI::SK_Broadcast: {
    bool HasScalar = (Args.size() > 0) && (Operator::getOpcode(Args[0]) ==
                                           Instruction::InsertElement);
    if (LT.second.getScalarSizeInBits() == 1) {
      if (HasScalar) {
        // Example sequence:
        //   andi a0, a0, 1
        //   vsetivli zero, 2, e8, mf8, ta, ma (ignored)
        //   vmv.v.x v8, a0
        //   vmsne.vi v0, v8, 0
        return LT.first *
               (TLI->getLMULCost(LT.second) + // FIXME: should be 1 for andi
                getRISCVInstructionCost({RISCV::VMV_V_X, RISCV::VMSNE_VI},
                                        LT.second, CostKind));
      }
      // Example sequence:
      //   vsetivli  zero, 2, e8, mf8, ta, mu (ignored)
      //   vmv.v.i v8, 0
      //   vmerge.vim      v8, v8, 1, v0
      //   vmv.x.s a0, v8
      //   andi    a0, a0, 1
      //   vmv.v.x v8, a0
      //   vmsne.vi  v0, v8, 0

      return LT.first *
             (TLI->getLMULCost(LT.second) + // FIXME: this should be 1 for andi
              getRISCVInstructionCost({RISCV::VMV_V_I, RISCV::VMERGE_VIM,
                                       RISCV::VMV_X_S, RISCV::VMV_V_X,
                                       RISCV::VMSNE_VI},
                                      LT.second, CostKind));
    }

    if (HasScalar) {
      // Example sequence:
      //   vmv.v.x v8, a0
      return LT.first *
             getRISCVInstructionCost(RISCV::VMV_V_X, LT.second, CostKind);
    }

    // Example sequence:
    //   vrgather.vi     v9, v8, 0
    return LT.first *
           getRISCVInstructionCost(RISCV::VRGATHER_VI, LT.second, CostKind);
  }
  case TTI::SK_Splice: {
    // vslidedown+vslideup.
    // TODO: Multiplying by LT.first implies this legalizes into multiple copies
    // of similar code, but I think we expand through memory.
    unsigned Opcodes[2] = {RISCV::VSLIDEDOWN_VX, RISCV::VSLIDEUP_VX};
    if (Index >= 0 && Index < 32)
      Opcodes[0] = RISCV::VSLIDEDOWN_VI;
    else if (Index < 0 && Index > -32)
      Opcodes[1] = RISCV::VSLIDEUP_VI;
    return LT.first * getRISCVInstructionCost(Opcodes, LT.second, CostKind);
  }
  case TTI::SK_Reverse: {
    // TODO: Cases to improve here:
    // * Illegal vector types
    // * i64 on RV32
    // * i1 vector
    // At low LMUL, most of the cost is producing the vrgather index register.
    // At high LMUL, the cost of the vrgather itself will dominate.
    // Example sequence:
    //   csrr a0, vlenb
    //   srli a0, a0, 3
    //   addi a0, a0, -1
    //   vsetvli a1, zero, e8, mf8, ta, mu (ignored)
    //   vid.v v9
    //   vrsub.vx v10, v9, a0
    //   vrgather.vv v9, v8, v10
    InstructionCost LenCost = 3;
    if (LT.second.isFixedLengthVector())
      // vrsub.vi has a 5 bit immediate field, otherwise an li suffices
      LenCost = isInt<5>(LT.second.getVectorNumElements() - 1) ? 0 : 1;
    // FIXME: replace the constant `2` below with cost of {VID_V,VRSUB_VX}
    InstructionCost GatherCost =
        2 + getRISCVInstructionCost(RISCV::VRGATHER_VV, LT.second, CostKind);
    // Mask operation additionally required extend and truncate
    InstructionCost ExtendCost = Tp->getElementType()->isIntegerTy(1) ? 3 : 0;
    return LT.first * (LenCost + GatherCost + ExtendCost);
  }
  }
  return BaseT::getShuffleCost(Kind, Tp, Mask, CostKind, Index, SubTp);
}

InstructionCost
RISCVTTIImpl::getMaskedMemoryOpCost(unsigned Opcode, Type *Src, Align Alignment,
                                    unsigned AddressSpace,
                                    TTI::TargetCostKind CostKind) {
  if (!isLegalMaskedLoadStore(Src, Alignment) ||
      CostKind != TTI::TCK_RecipThroughput)
    return BaseT::getMaskedMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
                                        CostKind);

  return getMemoryOpCost(Opcode, Src, Alignment, AddressSpace, CostKind);
}

InstructionCost RISCVTTIImpl::getInterleavedMemoryOpCost(
    unsigned Opcode, Type *VecTy, unsigned Factor, ArrayRef<unsigned> Indices,
    Align Alignment, unsigned AddressSpace, TTI::TargetCostKind CostKind,
    bool UseMaskForCond, bool UseMaskForGaps) {
  if (isa<ScalableVectorType>(VecTy))
    return InstructionCost::getInvalid();
  auto *FVTy = cast<FixedVectorType>(VecTy);
  InstructionCost MemCost =
      getMemoryOpCost(Opcode, VecTy, Alignment, AddressSpace, CostKind);
  unsigned VF = FVTy->getNumElements() / Factor;

  // The interleaved memory access pass will lower interleaved memory ops (i.e
  // a load and store followed by a specific shuffle) to vlseg/vsseg
  // intrinsics. In those cases then we can treat it as if it's just one (legal)
  // memory op
  if (!UseMaskForCond && !UseMaskForGaps &&
      Factor <= TLI->getMaxSupportedInterleaveFactor()) {
    std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(FVTy);
    // Need to make sure type has't been scalarized
    if (LT.second.isFixedLengthVector()) {
      auto *LegalFVTy = FixedVectorType::get(FVTy->getElementType(),
                                             LT.second.getVectorNumElements());
      // FIXME: We use the memory op cost of the *legalized* type here, becuase
      // it's getMemoryOpCost returns a really expensive cost for types like
      // <6 x i8>, which show up when doing interleaves of Factor=3 etc.
      // Should the memory op cost of these be cheaper?
      if (TLI->isLegalInterleavedAccessType(LegalFVTy, Factor, Alignment,
                                            AddressSpace, DL)) {
        InstructionCost LegalMemCost = getMemoryOpCost(
            Opcode, LegalFVTy, Alignment, AddressSpace, CostKind);
        return LT.first + LegalMemCost;
      }
    }
  }

  // An interleaved load will look like this for Factor=3:
  // %wide.vec = load <12 x i32>, ptr %3, align 4
  // %strided.vec = shufflevector %wide.vec, poison, <4 x i32> <stride mask>
  // %strided.vec1 = shufflevector %wide.vec, poison, <4 x i32> <stride mask>
  // %strided.vec2 = shufflevector %wide.vec, poison, <4 x i32> <stride mask>
  if (Opcode == Instruction::Load) {
    InstructionCost Cost = MemCost;
    for (unsigned Index : Indices) {
      FixedVectorType *SubVecTy =
          FixedVectorType::get(FVTy->getElementType(), VF * Factor);
      auto Mask = createStrideMask(Index, Factor, VF);
      InstructionCost ShuffleCost =
          getShuffleCost(TTI::ShuffleKind::SK_PermuteSingleSrc, SubVecTy, Mask,
                         CostKind, 0, nullptr, {});
      Cost += ShuffleCost;
    }
    return Cost;
  }

  // TODO: Model for NF > 2
  // We'll need to enhance getShuffleCost to model shuffles that are just
  // inserts and extracts into subvectors, since they won't have the full cost
  // of a vrgather.
  // An interleaved store for 3 vectors of 4 lanes will look like
  // %11 = shufflevector <4 x i32> %4, <4 x i32> %6, <8 x i32> <0...7>
  // %12 = shufflevector <4 x i32> %9, <4 x i32> poison, <8 x i32> <0...3>
  // %13 = shufflevector <8 x i32> %11, <8 x i32> %12, <12 x i32> <0...11>
  // %interleaved.vec = shufflevector %13, poison, <12 x i32> <interleave mask>
  // store <12 x i32> %interleaved.vec, ptr %10, align 4
  if (Factor != 2)
    return BaseT::getInterleavedMemoryOpCost(Opcode, VecTy, Factor, Indices,
                                             Alignment, AddressSpace, CostKind,
                                             UseMaskForCond, UseMaskForGaps);

  assert(Opcode == Instruction::Store && "Opcode must be a store");
  // For an interleaving store of 2 vectors, we perform one large interleaving
  // shuffle that goes into the wide store
  auto Mask = createInterleaveMask(VF, Factor);
  InstructionCost ShuffleCost =
      getShuffleCost(TTI::ShuffleKind::SK_PermuteSingleSrc, FVTy, Mask,
                     CostKind, 0, nullptr, {});
  return MemCost + ShuffleCost;
}

InstructionCost RISCVTTIImpl::getGatherScatterOpCost(
    unsigned Opcode, Type *DataTy, const Value *Ptr, bool VariableMask,
    Align Alignment, TTI::TargetCostKind CostKind, const Instruction *I) {
  if (CostKind != TTI::TCK_RecipThroughput)
    return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask,
                                         Alignment, CostKind, I);

  if ((Opcode == Instruction::Load &&
       !isLegalMaskedGather(DataTy, Align(Alignment))) ||
      (Opcode == Instruction::Store &&
       !isLegalMaskedScatter(DataTy, Align(Alignment))))
    return BaseT::getGatherScatterOpCost(Opcode, DataTy, Ptr, VariableMask,
                                         Alignment, CostKind, I);

  // Cost is proportional to the number of memory operations implied.  For
  // scalable vectors, we use an estimate on that number since we don't
  // know exactly what VL will be.
  auto &VTy = *cast<VectorType>(DataTy);
  InstructionCost MemOpCost =
      getMemoryOpCost(Opcode, VTy.getElementType(), Alignment, 0, CostKind,
                      {TTI::OK_AnyValue, TTI::OP_None}, I);
  unsigned NumLoads = getEstimatedVLFor(&VTy);
  return NumLoads * MemOpCost;
}

// Currently, these represent both throughput and codesize costs
// for the respective intrinsics.  The costs in this table are simply
// instruction counts with the following adjustments made:
// * One vsetvli is considered free.
static const CostTblEntry VectorIntrinsicCostTable[]{
    {Intrinsic::floor, MVT::f32, 9},
    {Intrinsic::floor, MVT::f64, 9},
    {Intrinsic::ceil, MVT::f32, 9},
    {Intrinsic::ceil, MVT::f64, 9},
    {Intrinsic::trunc, MVT::f32, 7},
    {Intrinsic::trunc, MVT::f64, 7},
    {Intrinsic::round, MVT::f32, 9},
    {Intrinsic::round, MVT::f64, 9},
    {Intrinsic::roundeven, MVT::f32, 9},
    {Intrinsic::roundeven, MVT::f64, 9},
    {Intrinsic::rint, MVT::f32, 7},
    {Intrinsic::rint, MVT::f64, 7},
    {Intrinsic::lrint, MVT::i32, 1},
    {Intrinsic::lrint, MVT::i64, 1},
    {Intrinsic::llrint, MVT::i64, 1},
    {Intrinsic::nearbyint, MVT::f32, 9},
    {Intrinsic::nearbyint, MVT::f64, 9},
    {Intrinsic::bswap, MVT::i16, 3},
    {Intrinsic::bswap, MVT::i32, 12},
    {Intrinsic::bswap, MVT::i64, 31},
    {Intrinsic::vp_bswap, MVT::i16, 3},
    {Intrinsic::vp_bswap, MVT::i32, 12},
    {Intrinsic::vp_bswap, MVT::i64, 31},
    {Intrinsic::vp_fshl, MVT::i8, 7},
    {Intrinsic::vp_fshl, MVT::i16, 7},
    {Intrinsic::vp_fshl, MVT::i32, 7},
    {Intrinsic::vp_fshl, MVT::i64, 7},
    {Intrinsic::vp_fshr, MVT::i8, 7},
    {Intrinsic::vp_fshr, MVT::i16, 7},
    {Intrinsic::vp_fshr, MVT::i32, 7},
    {Intrinsic::vp_fshr, MVT::i64, 7},
    {Intrinsic::bitreverse, MVT::i8, 17},
    {Intrinsic::bitreverse, MVT::i16, 24},
    {Intrinsic::bitreverse, MVT::i32, 33},
    {Intrinsic::bitreverse, MVT::i64, 52},
    {Intrinsic::vp_bitreverse, MVT::i8, 17},
    {Intrinsic::vp_bitreverse, MVT::i16, 24},
    {Intrinsic::vp_bitreverse, MVT::i32, 33},
    {Intrinsic::vp_bitreverse, MVT::i64, 52},
    {Intrinsic::ctpop, MVT::i8, 12},
    {Intrinsic::ctpop, MVT::i16, 19},
    {Intrinsic::ctpop, MVT::i32, 20},
    {Intrinsic::ctpop, MVT::i64, 21},
    {Intrinsic::vp_ctpop, MVT::i8, 12},
    {Intrinsic::vp_ctpop, MVT::i16, 19},
    {Intrinsic::vp_ctpop, MVT::i32, 20},
    {Intrinsic::vp_ctpop, MVT::i64, 21},
    {Intrinsic::vp_ctlz, MVT::i8, 19},
    {Intrinsic::vp_ctlz, MVT::i16, 28},
    {Intrinsic::vp_ctlz, MVT::i32, 31},
    {Intrinsic::vp_ctlz, MVT::i64, 35},
    {Intrinsic::vp_cttz, MVT::i8, 16},
    {Intrinsic::vp_cttz, MVT::i16, 23},
    {Intrinsic::vp_cttz, MVT::i32, 24},
    {Intrinsic::vp_cttz, MVT::i64, 25},
};

static unsigned getISDForVPIntrinsicID(Intrinsic::ID ID) {
  switch (ID) {
#define HELPER_MAP_VPID_TO_VPSD(VPID, VPSD)                                    \
  case Intrinsic::VPID:                                                        \
    return ISD::VPSD;
#include "llvm/IR/VPIntrinsics.def"
#undef HELPER_MAP_VPID_TO_VPSD
  }
  return ISD::DELETED_NODE;
}

InstructionCost
RISCVTTIImpl::getIntrinsicInstrCost(const IntrinsicCostAttributes &ICA,
                                    TTI::TargetCostKind CostKind) {
  auto *RetTy = ICA.getReturnType();
  switch (ICA.getID()) {
  case Intrinsic::ceil:
  case Intrinsic::floor:
  case Intrinsic::trunc:
  case Intrinsic::rint:
  case Intrinsic::lrint:
  case Intrinsic::llrint:
  case Intrinsic::round:
  case Intrinsic::roundeven: {
    // These all use the same code.
    auto LT = getTypeLegalizationCost(RetTy);
    if (!LT.second.isVector() && TLI->isOperationCustom(ISD::FCEIL, LT.second))
      return LT.first * 8;
    break;
  }
  case Intrinsic::umin:
  case Intrinsic::umax:
  case Intrinsic::smin:
  case Intrinsic::smax: {
    auto LT = getTypeLegalizationCost(RetTy);
    if ((ST->hasVInstructions() && LT.second.isVector()) ||
        (LT.second.isScalarInteger() && ST->hasStdExtZbb()))
      return LT.first;
    break;
  }
  case Intrinsic::sadd_sat:
  case Intrinsic::ssub_sat:
  case Intrinsic::uadd_sat:
  case Intrinsic::usub_sat:
  case Intrinsic::fabs:
  case Intrinsic::sqrt: {
    auto LT = getTypeLegalizationCost(RetTy);
    if (ST->hasVInstructions() && LT.second.isVector())
      return LT.first;
    break;
  }
  case Intrinsic::ctpop: {
    auto LT = getTypeLegalizationCost(RetTy);
    if (ST->hasVInstructions() && ST->hasStdExtZvbb() && LT.second.isVector())
      return LT.first;
    break;
  }
  case Intrinsic::abs: {
    auto LT = getTypeLegalizationCost(RetTy);
    if (ST->hasVInstructions() && LT.second.isVector()) {
      // vrsub.vi v10, v8, 0
      // vmax.vv v8, v8, v10
      return LT.first * 2;
    }
    break;
  }
  // TODO: add more intrinsic
  case Intrinsic::experimental_stepvector: {
    unsigned Cost = 1; // vid
    auto LT = getTypeLegalizationCost(RetTy);
    return Cost + (LT.first - 1);
  }
  case Intrinsic::vp_rint: {
    // RISC-V target uses at least 5 instructions to lower rounding intrinsics.
    unsigned Cost = 5;
    auto LT = getTypeLegalizationCost(RetTy);
    if (TLI->isOperationCustom(ISD::VP_FRINT, LT.second))
      return Cost * LT.first;
    break;
  }
  case Intrinsic::vp_nearbyint: {
    // More one read and one write for fflags than vp_rint.
    unsigned Cost = 7;
    auto LT = getTypeLegalizationCost(RetTy);
    if (TLI->isOperationCustom(ISD::VP_FRINT, LT.second))
      return Cost * LT.first;
    break;
  }
  case Intrinsic::vp_ceil:
  case Intrinsic::vp_floor:
  case Intrinsic::vp_round:
  case Intrinsic::vp_roundeven:
  case Intrinsic::vp_roundtozero: {
    // Rounding with static rounding mode needs two more instructions to
    // swap/write FRM than vp_rint.
    unsigned Cost = 7;
    auto LT = getTypeLegalizationCost(RetTy);
    unsigned VPISD = getISDForVPIntrinsicID(ICA.getID());
    if (TLI->isOperationCustom(VPISD, LT.second))
      return Cost * LT.first;
    break;
  }
  }

  if (ST->hasVInstructions() && RetTy->isVectorTy()) {
    if (auto LT = getTypeLegalizationCost(RetTy);
        LT.second.isVector()) {
      MVT EltTy = LT.second.getVectorElementType();
      if (const auto *Entry = CostTableLookup(VectorIntrinsicCostTable,
                                              ICA.getID(), EltTy))
        return LT.first * Entry->Cost;
    }
  }

  return BaseT::getIntrinsicInstrCost(ICA, CostKind);
}

InstructionCost RISCVTTIImpl::getCastInstrCost(unsigned Opcode, Type *Dst,
                                               Type *Src,
                                               TTI::CastContextHint CCH,
                                               TTI::TargetCostKind CostKind,
                                               const Instruction *I) {
  if (isa<VectorType>(Dst) && isa<VectorType>(Src)) {
    // FIXME: Need to compute legalizing cost for illegal types.
    if (!isTypeLegal(Src) || !isTypeLegal(Dst))
      return BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I);

    // Skip if element size of Dst or Src is bigger than ELEN.
    if (Src->getScalarSizeInBits() > ST->getELen() ||
        Dst->getScalarSizeInBits() > ST->getELen())
      return BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I);

    int ISD = TLI->InstructionOpcodeToISD(Opcode);
    assert(ISD && "Invalid opcode");

    // FIXME: Need to consider vsetvli and lmul.
    int PowDiff = (int)Log2_32(Dst->getScalarSizeInBits()) -
                  (int)Log2_32(Src->getScalarSizeInBits());
    switch (ISD) {
    case ISD::SIGN_EXTEND:
    case ISD::ZERO_EXTEND:
      if (Src->getScalarSizeInBits() == 1) {
        // We do not use vsext/vzext to extend from mask vector.
        // Instead we use the following instructions to extend from mask vector:
        // vmv.v.i v8, 0
        // vmerge.vim v8, v8, -1, v0
        return 2;
      }
      return 1;
    case ISD::TRUNCATE:
      if (Dst->getScalarSizeInBits() == 1) {
        // We do not use several vncvt to truncate to mask vector. So we could
        // not use PowDiff to calculate it.
        // Instead we use the following instructions to truncate to mask vector:
        // vand.vi v8, v8, 1
        // vmsne.vi v0, v8, 0
        return 2;
      }
      [[fallthrough]];
    case ISD::FP_EXTEND:
    case ISD::FP_ROUND:
      // Counts of narrow/widen instructions.
      return std::abs(PowDiff);
    case ISD::FP_TO_SINT:
    case ISD::FP_TO_UINT:
    case ISD::SINT_TO_FP:
    case ISD::UINT_TO_FP:
      if (Src->getScalarSizeInBits() == 1 || Dst->getScalarSizeInBits() == 1) {
        // The cost of convert from or to mask vector is different from other
        // cases. We could not use PowDiff to calculate it.
        // For mask vector to fp, we should use the following instructions:
        // vmv.v.i v8, 0
        // vmerge.vim v8, v8, -1, v0
        // vfcvt.f.x.v v8, v8

        // And for fp vector to mask, we use:
        // vfncvt.rtz.x.f.w v9, v8
        // vand.vi v8, v9, 1
        // vmsne.vi v0, v8, 0
        return 3;
      }
      if (std::abs(PowDiff) <= 1)
        return 1;
      // Backend could lower (v[sz]ext i8 to double) to vfcvt(v[sz]ext.f8 i8),
      // so it only need two conversion.
      if (Src->isIntOrIntVectorTy())
        return 2;
      // Counts of narrow/widen instructions.
      return std::abs(PowDiff);
    }
  }
  return BaseT::getCastInstrCost(Opcode, Dst, Src, CCH, CostKind, I);
}

unsigned RISCVTTIImpl::getEstimatedVLFor(VectorType *Ty) {
  if (isa<ScalableVectorType>(Ty)) {
    const unsigned EltSize = DL.getTypeSizeInBits(Ty->getElementType());
    const unsigned MinSize = DL.getTypeSizeInBits(Ty).getKnownMinValue();
    const unsigned VectorBits = *getVScaleForTuning() * RISCV::RVVBitsPerBlock;
    return RISCVTargetLowering::computeVLMAX(VectorBits, EltSize, MinSize);
  }
  return cast<FixedVectorType>(Ty)->getNumElements();
}

InstructionCost
RISCVTTIImpl::getMinMaxReductionCost(Intrinsic::ID IID, VectorType *Ty,
                                     FastMathFlags FMF,
                                     TTI::TargetCostKind CostKind) {
  if (isa<FixedVectorType>(Ty) && !ST->useRVVForFixedLengthVectors())
    return BaseT::getMinMaxReductionCost(IID, Ty, FMF, CostKind);

  // Skip if scalar size of Ty is bigger than ELEN.
  if (Ty->getScalarSizeInBits() > ST->getELen())
    return BaseT::getMinMaxReductionCost(IID, Ty, FMF, CostKind);

  std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
  if (Ty->getElementType()->isIntegerTy(1))
    // vcpop sequences, see vreduction-mask.ll.  umax, smin actually only
    // cost 2, but we don't have enough info here so we slightly over cost.
    return (LT.first - 1) + 3;

  // IR Reduction is composed by two vmv and one rvv reduction instruction.
  InstructionCost BaseCost = 2;

  if (CostKind == TTI::TCK_CodeSize)
    return (LT.first - 1) + BaseCost;

  unsigned VL = getEstimatedVLFor(Ty);
  return (LT.first - 1) + BaseCost + Log2_32_Ceil(VL);
}

InstructionCost
RISCVTTIImpl::getArithmeticReductionCost(unsigned Opcode, VectorType *Ty,
                                         std::optional<FastMathFlags> FMF,
                                         TTI::TargetCostKind CostKind) {
  if (isa<FixedVectorType>(Ty) && !ST->useRVVForFixedLengthVectors())
    return BaseT::getArithmeticReductionCost(Opcode, Ty, FMF, CostKind);

  // Skip if scalar size of Ty is bigger than ELEN.
  if (Ty->getScalarSizeInBits() > ST->getELen())
    return BaseT::getArithmeticReductionCost(Opcode, Ty, FMF, CostKind);

  int ISD = TLI->InstructionOpcodeToISD(Opcode);
  assert(ISD && "Invalid opcode");

  if (ISD != ISD::ADD && ISD != ISD::OR && ISD != ISD::XOR && ISD != ISD::AND &&
      ISD != ISD::FADD)
    return BaseT::getArithmeticReductionCost(Opcode, Ty, FMF, CostKind);

  std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);
  if (Ty->getElementType()->isIntegerTy(1))
    // vcpop sequences, see vreduction-mask.ll
    return (LT.first - 1) + (ISD == ISD::AND ? 3 : 2);

  // IR Reduction is composed by two vmv and one rvv reduction instruction.
  InstructionCost BaseCost = 2;

  if (CostKind == TTI::TCK_CodeSize)
    return (LT.first - 1) + BaseCost;

  unsigned VL = getEstimatedVLFor(Ty);
  if (TTI::requiresOrderedReduction(FMF))
    return (LT.first - 1) + BaseCost + VL;
  return (LT.first - 1) + BaseCost + Log2_32_Ceil(VL);
}

InstructionCost RISCVTTIImpl::getExtendedReductionCost(
    unsigned Opcode, bool IsUnsigned, Type *ResTy, VectorType *ValTy,
    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 = getTypeLegalizationCost(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);
}

InstructionCost RISCVTTIImpl::getStoreImmCost(Type *Ty,
                                              TTI::OperandValueInfo OpInfo,
                                              TTI::TargetCostKind CostKind) {
  assert(OpInfo.isConstant() && "non constant operand?");
  if (!isa<VectorType>(Ty))
    // FIXME: We need to account for immediate materialization here, but doing
    // a decent job requires more knowledge about the immediate than we
    // currently have here.
    return 0;

  if (OpInfo.isUniform())
    // vmv.x.i, vmv.v.x, or vfmv.v.f
    // We ignore the cost of the scalar constant materialization to be consistent
    // with how we treat scalar constants themselves just above.
    return 1;

  return getConstantPoolLoadCost(Ty, CostKind);
}


InstructionCost RISCVTTIImpl::getMemoryOpCost(unsigned Opcode, Type *Src,
                                              MaybeAlign Alignment,
                                              unsigned AddressSpace,
                                              TTI::TargetCostKind CostKind,
                                              TTI::OperandValueInfo OpInfo,
                                              const Instruction *I) {
  EVT VT = TLI->getValueType(DL, Src, true);
  // Type legalization can't handle structs
  if (VT == MVT::Other)
    return BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
                                  CostKind, OpInfo, I);

  InstructionCost Cost = 0;
  if (Opcode == Instruction::Store && OpInfo.isConstant())
    Cost += getStoreImmCost(Src, OpInfo, CostKind);
  InstructionCost BaseCost =
    BaseT::getMemoryOpCost(Opcode, Src, Alignment, AddressSpace,
                           CostKind, OpInfo, I);
  // Assume memory ops cost scale with the number of vector registers
  // possible accessed by the instruction.  Note that BasicTTI already
  // handles the LT.first term for us.
  if (std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Src);
      LT.second.isVector() && CostKind != TTI::TCK_CodeSize)
    BaseCost *= TLI->getLMULCost(LT.second);
  return Cost + BaseCost;

}

InstructionCost RISCVTTIImpl::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
                                                 Type *CondTy,
                                                 CmpInst::Predicate VecPred,
                                                 TTI::TargetCostKind CostKind,
                                                 const Instruction *I) {
  if (CostKind != TTI::TCK_RecipThroughput)
    return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
                                     I);

  if (isa<FixedVectorType>(ValTy) && !ST->useRVVForFixedLengthVectors())
    return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
                                     I);

  // Skip if scalar size of ValTy is bigger than ELEN.
  if (ValTy->isVectorTy() && ValTy->getScalarSizeInBits() > ST->getELen())
    return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
                                     I);

  if (Opcode == Instruction::Select && ValTy->isVectorTy()) {
    std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);
    if (CondTy->isVectorTy()) {
      if (ValTy->getScalarSizeInBits() == 1) {
        // vmandn.mm v8, v8, v9
        // vmand.mm v9, v0, v9
        // vmor.mm v0, v9, v8
        return LT.first * 3;
      }
      // vselect and max/min are supported natively.
      return LT.first * 1;
    }

    if (ValTy->getScalarSizeInBits() == 1) {
      //  vmv.v.x v9, a0
      //  vmsne.vi v9, v9, 0
      //  vmandn.mm v8, v8, v9
      //  vmand.mm v9, v0, v9
      //  vmor.mm v0, v9, v8
      return LT.first * 5;
    }

    // vmv.v.x v10, a0
    // vmsne.vi v0, v10, 0
    // vmerge.vvm v8, v9, v8, v0
    return LT.first * 3;
  }

  if ((Opcode == Instruction::ICmp || Opcode == Instruction::FCmp) &&
      ValTy->isVectorTy()) {
    std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(ValTy);

    // Support natively.
    if (CmpInst::isIntPredicate(VecPred))
      return LT.first * 1;

    // 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,
    // InvalidCost for scalable vector.
    if ((ValTy->getScalarSizeInBits() == 16 && !ST->hasVInstructionsF16()) ||
        (ValTy->getScalarSizeInBits() == 32 && !ST->hasVInstructionsF32()) ||
        (ValTy->getScalarSizeInBits() == 64 && !ST->hasVInstructionsF64()))
      return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind,
                                       I);
    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?
    default:
      break;
    }
  }

  // TODO: Add cost for scalar type.

  return BaseT::getCmpSelInstrCost(Opcode, ValTy, CondTy, VecPred, CostKind, I);
}

InstructionCost RISCVTTIImpl::getCFInstrCost(unsigned Opcode,
                                             TTI::TargetCostKind CostKind,
                                             const Instruction *I) {
  if (CostKind != TTI::TCK_RecipThroughput)
    return Opcode == Instruction::PHI ? 0 : 1;
  // Branches are assumed to be predicted.
  return 0;
}

InstructionCost RISCVTTIImpl::getVectorInstrCost(unsigned Opcode, Type *Val,
                                                 TTI::TargetCostKind CostKind,
                                                 unsigned Index, Value *Op0,
                                                 Value *Op1) {
  assert(Val->isVectorTy() && "This must be a vector type");

  if (Opcode != Instruction::ExtractElement &&
      Opcode != Instruction::InsertElement)
    return BaseT::getVectorInstrCost(Opcode, Val, CostKind, Index, Op0, Op1);

  // Legalize the type.
  std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Val);

  // This type is legalized to a scalar type.
  if (!LT.second.isVector()) {
    auto *FixedVecTy = cast<FixedVectorType>(Val);
    // If Index is a known constant, cost is zero.
    if (Index != -1U)
      return 0;
    // Extract/InsertElement with non-constant index is very costly when
    // scalarized; estimate cost of loads/stores sequence via the stack:
    // ExtractElement cost: store vector to stack, load scalar;
    // InsertElement cost: store vector to stack, store scalar, load vector.
    Type *ElemTy = FixedVecTy->getElementType();
    auto NumElems = FixedVecTy->getNumElements();
    auto Align = DL.getPrefTypeAlign(ElemTy);
    InstructionCost LoadCost =
        getMemoryOpCost(Instruction::Load, ElemTy, Align, 0, CostKind);
    InstructionCost StoreCost =
        getMemoryOpCost(Instruction::Store, ElemTy, Align, 0, CostKind);
    return Opcode == Instruction::ExtractElement
               ? StoreCost * NumElems + LoadCost
               : (StoreCost + LoadCost) * NumElems + StoreCost;
  }

  // For unsupported scalable vector.
  if (LT.second.isScalableVector() && !LT.first.isValid())
    return LT.first;

  if (!isTypeLegal(Val))
    return BaseT::getVectorInstrCost(Opcode, Val, CostKind, Index, Op0, Op1);

  // Mask vector extract/insert is expanded via e8.
  if (Val->getScalarSizeInBits() == 1) {
    VectorType *WideTy =
      VectorType::get(IntegerType::get(Val->getContext(), 8),
                      cast<VectorType>(Val)->getElementCount());
    if (Opcode == Instruction::ExtractElement) {
      InstructionCost ExtendCost
        = getCastInstrCost(Instruction::ZExt, WideTy, Val,
                           TTI::CastContextHint::None, CostKind);
      InstructionCost ExtractCost
        = getVectorInstrCost(Opcode, WideTy, CostKind, Index, nullptr, nullptr);
      return ExtendCost + ExtractCost;
    }
    InstructionCost ExtendCost
      = getCastInstrCost(Instruction::ZExt, WideTy, Val,
                         TTI::CastContextHint::None, CostKind);
    InstructionCost InsertCost
      = getVectorInstrCost(Opcode, WideTy, CostKind, Index, nullptr, nullptr);
    InstructionCost TruncCost
      = getCastInstrCost(Instruction::Trunc, Val, WideTy,
                         TTI::CastContextHint::None, CostKind);
    return ExtendCost + InsertCost + TruncCost;
  }


  // In RVV, we could use vslidedown + vmv.x.s to extract element from vector
  // and vslideup + vmv.s.x to insert element to vector.
  unsigned BaseCost = 1;
  // When insertelement we should add the index with 1 as the input of vslideup.
  unsigned SlideCost = Opcode == Instruction::InsertElement ? 2 : 1;

  if (Index != -1U) {
    // The type may be split. For fixed-width vectors we can normalize the
    // index to the new type.
    if (LT.second.isFixedLengthVector()) {
      unsigned Width = LT.second.getVectorNumElements();
      Index = Index % Width;
    }

    // We could extract/insert the first element without vslidedown/vslideup.
    if (Index == 0)
      SlideCost = 0;
    else if (Opcode == Instruction::InsertElement)
      SlideCost = 1; // With a constant index, we do not need to use addi.
  }

  // Extract i64 in the target that has XLEN=32 need more instruction.
  if (Val->getScalarType()->isIntegerTy() &&
      ST->getXLen() < Val->getScalarSizeInBits()) {
    // For extractelement, we need the following instructions:
    // vsetivli zero, 1, e64, m1, ta, mu (not count)
    // vslidedown.vx v8, v8, a0
    // vmv.x.s a0, v8
    // li a1, 32
    // vsrl.vx v8, v8, a1
    // vmv.x.s a1, v8

    // For insertelement, we need the following instructions:
    // vsetivli zero, 2, e32, m4, ta, mu (not count)
    // vmv.v.i v12, 0
    // vslide1up.vx v16, v12, a1
    // vslide1up.vx v12, v16, a0
    // addi a0, a2, 1
    // vsetvli zero, a0, e64, m4, tu, mu (not count)
    // vslideup.vx v8, v12, a2

    // TODO: should we count these special vsetvlis?
    BaseCost = Opcode == Instruction::InsertElement ? 3 : 4;
  }
  return BaseCost + SlideCost;
}

InstructionCost RISCVTTIImpl::getArithmeticInstrCost(
    unsigned Opcode, Type *Ty, TTI::TargetCostKind CostKind,
    TTI::OperandValueInfo Op1Info, TTI::OperandValueInfo Op2Info,
    ArrayRef<const Value *> Args, const Instruction *CxtI) {

  // TODO: Handle more cost kinds.
  if (CostKind != TTI::TCK_RecipThroughput)
    return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info, Op2Info,
                                         Args, CxtI);

  if (isa<FixedVectorType>(Ty) && !ST->useRVVForFixedLengthVectors())
    return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info, Op2Info,
                                         Args, CxtI);

  // Skip if scalar size of Ty is bigger than ELEN.
  if (isa<VectorType>(Ty) && Ty->getScalarSizeInBits() > ST->getELen())
    return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info, Op2Info,
                                         Args, CxtI);

  // Legalize the type.
  std::pair<InstructionCost, MVT> LT = getTypeLegalizationCost(Ty);

  // TODO: Handle scalar type.
  if (!LT.second.isVector())
    return BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info, Op2Info,
                                         Args, CxtI);


  auto getConstantMatCost =
    [&](unsigned Operand, TTI::OperandValueInfo OpInfo) -> InstructionCost {
    if (OpInfo.isUniform() && TLI->canSplatOperand(Opcode, Operand))
      // Two sub-cases:
      // * Has a 5 bit immediate operand which can be splatted.
      // * Has a larger immediate which must be materialized in scalar register
      // We return 0 for both as we currently ignore the cost of materializing
      // scalar constants in GPRs.
      return 0;

    return getConstantPoolLoadCost(Ty, CostKind);
  };

  // Add the cost of materializing any constant vectors required.
  InstructionCost ConstantMatCost = 0;
  if (Op1Info.isConstant())
    ConstantMatCost += getConstantMatCost(0, Op1Info);
  if (Op2Info.isConstant())
    ConstantMatCost += getConstantMatCost(1, Op2Info);

  switch (TLI->InstructionOpcodeToISD(Opcode)) {
  case ISD::ADD:
  case ISD::SUB:
  case ISD::AND:
  case ISD::OR:
  case ISD::XOR:
  case ISD::SHL:
  case ISD::SRL:
  case ISD::SRA:
  case ISD::MUL:
  case ISD::MULHS:
  case ISD::MULHU:
  case ISD::FADD:
  case ISD::FSUB:
  case ISD::FMUL:
  case ISD::FNEG: {
    return ConstantMatCost + TLI->getLMULCost(LT.second) * LT.first * 1;
  }
  default:
    return ConstantMatCost +
           BaseT::getArithmeticInstrCost(Opcode, Ty, CostKind, Op1Info, Op2Info,
                                         Args, CxtI);
  }
}

// TODO: Deduplicate from TargetTransformInfoImplCRTPBase.
InstructionCost RISCVTTIImpl::getPointersChainCost(
    ArrayRef<const Value *> Ptrs, const Value *Base,
    const TTI::PointersChainInfo &Info, Type *AccessTy,
    TTI::TargetCostKind CostKind) {
  InstructionCost Cost = TTI::TCC_Free;
  // In the basic model we take into account GEP instructions only
  // (although here can come alloca instruction, a value, constants and/or
  // constant expressions, PHIs, bitcasts ... whatever allowed to be used as a
  // pointer). Typically, if Base is a not a GEP-instruction and all the
  // pointers are relative to the same base address, all the rest are
  // either GEP instructions, PHIs, bitcasts or constants. When we have same
  // base, we just calculate cost of each non-Base GEP as an ADD operation if
  // any their index is a non-const.
  // If no known dependecies between the pointers cost is calculated as a sum
  // of costs of GEP instructions.
  for (auto [I, V] : enumerate(Ptrs)) {
    const auto *GEP = dyn_cast<GetElementPtrInst>(V);
    if (!GEP)
      continue;
    if (Info.isSameBase() && V != Base) {
      if (GEP->hasAllConstantIndices())
        continue;
      // If the chain is unit-stride and BaseReg + stride*i is a legal
      // addressing mode, then presume the base GEP is sitting around in a
      // register somewhere and check if we can fold the offset relative to
      // it.
      unsigned Stride = DL.getTypeStoreSize(AccessTy);
      if (Info.isUnitStride() &&
          isLegalAddressingMode(AccessTy,
                                /* BaseGV */ nullptr,
                                /* BaseOffset */ Stride * I,
                                /* HasBaseReg */ true,
                                /* Scale */ 0,
                                GEP->getType()->getPointerAddressSpace()))
        continue;
      Cost += getArithmeticInstrCost(Instruction::Add, GEP->getType(), CostKind,
                                     {TTI::OK_AnyValue, TTI::OP_None},
                                     {TTI::OK_AnyValue, TTI::OP_None},
                                     std::nullopt);
    } else {
      SmallVector<const Value *> Indices(GEP->indices());
      Cost += getGEPCost(GEP->getSourceElementType(), GEP->getPointerOperand(),
                         Indices, AccessTy, CostKind);
    }
  }
  return Cost;
}

void RISCVTTIImpl::getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
                                           TTI::UnrollingPreferences &UP,
                                           OptimizationRemarkEmitter *ORE) {
  // TODO: More tuning on benchmarks and metrics with changes as needed
  //       would apply to all settings below to enable performance.


  if (ST->enableDefaultUnroll())
    return BasicTTIImplBase::getUnrollingPreferences(L, SE, UP, ORE);

  // Enable Upper bound unrolling universally, not dependant upon the conditions
  // below.
  UP.UpperBound = true;

  // Disable loop unrolling for Oz and Os.
  UP.OptSizeThreshold = 0;
  UP.PartialOptSizeThreshold = 0;
  if (L->getHeader()->getParent()->hasOptSize())
    return;

  SmallVector<BasicBlock *, 4> ExitingBlocks;
  L->getExitingBlocks(ExitingBlocks);
  LLVM_DEBUG(dbgs() << "Loop has:\n"
                    << "Blocks: " << L->getNumBlocks() << "\n"
                    << "Exit blocks: " << ExitingBlocks.size() << "\n");

  // Only allow another exit other than the latch. This acts as an early exit
  // as it mirrors the profitability calculation of the runtime unroller.
  if (ExitingBlocks.size() > 2)
    return;

  // Limit the CFG of the loop body for targets with a branch predictor.
  // Allowing 4 blocks permits if-then-else diamonds in the body.
  if (L->getNumBlocks() > 4)
    return;

  // Don't unroll vectorized loops, including the remainder loop
  if (getBooleanLoopAttribute(L, "llvm.loop.isvectorized"))
    return;

  // Scan the loop: don't unroll loops with calls as this could prevent
  // inlining.
  InstructionCost Cost = 0;
  for (auto *BB : L->getBlocks()) {
    for (auto &I : *BB) {
      // Initial setting - Don't unroll loops containing vectorized
      // instructions.
      if (I.getType()->isVectorTy())
        return;

      if (isa<CallInst>(I) || isa<InvokeInst>(I)) {
        if (const Function *F = cast<CallBase>(I).getCalledFunction()) {
          if (!isLoweredToCall(F))
            continue;
        }
        return;
      }

      SmallVector<const Value *> Operands(I.operand_values());
      Cost += getInstructionCost(&I, Operands,
                                 TargetTransformInfo::TCK_SizeAndLatency);
    }
  }

  LLVM_DEBUG(dbgs() << "Cost of loop: " << Cost << "\n");

  UP.Partial = true;
  UP.Runtime = true;
  UP.UnrollRemainder = true;
  UP.UnrollAndJam = true;
  UP.UnrollAndJamInnerLoopThreshold = 60;

  // Force unrolling small loops can be very useful because of the branch
  // taken cost of the backedge.
  if (Cost < 12)
    UP.Force = true;
}

void RISCVTTIImpl::getPeelingPreferences(Loop *L, ScalarEvolution &SE,
                                         TTI::PeelingPreferences &PP) {
  BaseT::getPeelingPreferences(L, SE, PP);
}

unsigned RISCVTTIImpl::getRegUsageForType(Type *Ty) {
  TypeSize Size = DL.getTypeSizeInBits(Ty);
  if (Ty->isVectorTy()) {
    if (Size.isScalable() && ST->hasVInstructions())
      return divideCeil(Size.getKnownMinValue(), RISCV::RVVBitsPerBlock);

    if (ST->useRVVForFixedLengthVectors())
      return divideCeil(Size, ST->getRealMinVLen());
  }

  return BaseT::getRegUsageForType(Ty);
}

unsigned RISCVTTIImpl::getMaximumVF(unsigned ElemWidth, unsigned Opcode) const {
  if (SLPMaxVF.getNumOccurrences())
    return SLPMaxVF;

  // Return how many elements can fit in getRegisterBitwidth.  This is the
  // same routine as used in LoopVectorizer.  We should probably be
  // accounting for whether we actually have instructions with the right
  // lane type, but we don't have enough information to do that without
  // some additional plumbing which hasn't been justified yet.
  TypeSize RegWidth =
    getRegisterBitWidth(TargetTransformInfo::RGK_FixedWidthVector);
  // If no vector registers, or absurd element widths, disable
  // vectorization by returning 1.
  return std::max<unsigned>(1U, RegWidth.getFixedValue() / ElemWidth);
}

bool RISCVTTIImpl::isLSRCostLess(const TargetTransformInfo::LSRCost &C1,
                                 const TargetTransformInfo::LSRCost &C2) {
  // RISC-V specific here are "instruction number 1st priority".
  return std::tie(C1.Insns, C1.NumRegs, C1.AddRecCost,
                  C1.NumIVMuls, C1.NumBaseAdds,
                  C1.ScaleCost, C1.ImmCost, C1.SetupCost) <
         std::tie(C2.Insns, C2.NumRegs, C2.AddRecCost,
                  C2.NumIVMuls, C2.NumBaseAdds,
                  C2.ScaleCost, C2.ImmCost, C2.SetupCost);
}