llvm/lib/Target/X86/X86TargetTransformInfo.cpp

//===-- X86TargetTransformInfo.cpp - X86 specific TTI pass ----------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
/// This file implements a TargetTransformInfo analysis pass specific to the
/// X86 target machine. It uses the target's detailed information to provide
/// more precise answers to certain TTI queries, while letting the target
/// independent and default TTI implementations handle the rest.
///
//===----------------------------------------------------------------------===//

#include "X86.h"
#include "X86TargetMachine.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/Support/Debug.h"
#include "llvm/Target/CostTable.h"
#include "llvm/Target/TargetLowering.h"
using namespace llvm;

#define DEBUG_TYPE "x86tti"

// Declare the pass initialization routine locally as target-specific passes
// don't have a target-wide initialization entry point, and so we rely on the
// pass constructor initialization.
namespace llvm {
void initializeX86TTIPass(PassRegistry &);
}

namespace {

class X86TTI final : public ImmutablePass, public TargetTransformInfo {
  const X86Subtarget *ST;
  const X86TargetLowering *TLI;

  /// Estimate the overhead of scalarizing an instruction. Insert and Extract
  /// are set if the result needs to be inserted and/or extracted from vectors.
  unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract) const;

public:
  X86TTI() : ImmutablePass(ID), ST(nullptr), TLI(nullptr) {
    llvm_unreachable("This pass cannot be directly constructed");
  }

  X86TTI(const X86TargetMachine *TM)
      : ImmutablePass(ID), ST(TM->getSubtargetImpl()),
        TLI(TM->getSubtargetImpl()->getTargetLowering()) {
    initializeX86TTIPass(*PassRegistry::getPassRegistry());
  }

  void initializePass() override {
    pushTTIStack(this);
  }

  void getAnalysisUsage(AnalysisUsage &AU) const override {
    TargetTransformInfo::getAnalysisUsage(AU);
  }

  /// Pass identification.
  static char ID;

  /// Provide necessary pointer adjustments for the two base classes.
  void *getAdjustedAnalysisPointer(const void *ID) override {
    if (ID == &TargetTransformInfo::ID)
      return (TargetTransformInfo*)this;
    return this;
  }

  /// \name Scalar TTI Implementations
  /// @{
  PopcntSupportKind getPopcntSupport(unsigned TyWidth) const override;

  /// @}

  /// \name Vector TTI Implementations
  /// @{

  unsigned getNumberOfRegisters(bool Vector) const override;
  unsigned getRegisterBitWidth(bool Vector) const override;
  unsigned getMaxInterleaveFactor() const override;
  unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty, OperandValueKind,
                                  OperandValueKind, OperandValueProperties,
                                  OperandValueProperties) const override;
  unsigned getShuffleCost(ShuffleKind Kind, Type *Tp,
                          int Index, Type *SubTp) const override;
  unsigned getCastInstrCost(unsigned Opcode, Type *Dst,
                            Type *Src) const override;
  unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
                              Type *CondTy) const override;
  unsigned getVectorInstrCost(unsigned Opcode, Type *Val,
                              unsigned Index) const override;
  unsigned getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
                           unsigned AddressSpace) const override;

  unsigned getAddressComputationCost(Type *PtrTy,
                                     bool IsComplex) const override;

  unsigned getReductionCost(unsigned Opcode, Type *Ty,
                            bool IsPairwiseForm) const override;

  unsigned getIntImmCost(int64_t) const;

  unsigned getIntImmCost(const APInt &Imm, Type *Ty) const override;

  unsigned getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
                         Type *Ty) const override;
  unsigned getIntImmCost(Intrinsic::ID IID, unsigned Idx, const APInt &Imm,
                         Type *Ty) const override;

  /// @}
};

} // end anonymous namespace

INITIALIZE_AG_PASS(X86TTI, TargetTransformInfo, "x86tti",
                   "X86 Target Transform Info", true, true, false)
char X86TTI::ID = 0;

ImmutablePass *
llvm::createX86TargetTransformInfoPass(const X86TargetMachine *TM) {
  return new X86TTI(TM);
}


//===----------------------------------------------------------------------===//
//
// X86 cost model.
//
//===----------------------------------------------------------------------===//

X86TTI::PopcntSupportKind X86TTI::getPopcntSupport(unsigned TyWidth) const {
  assert(isPowerOf2_32(TyWidth) && "Ty width must be power of 2");
  // TODO: Currently the __builtin_popcount() implementation using SSE3
  //   instructions is inefficient. Once the problem is fixed, we should
  //   call ST->hasSSE3() instead of ST->hasPOPCNT().
  return ST->hasPOPCNT() ? PSK_FastHardware : PSK_Software;
}

unsigned X86TTI::getNumberOfRegisters(bool Vector) const {
  if (Vector && !ST->hasSSE1())
    return 0;

  if (ST->is64Bit()) {
    if (Vector && ST->hasAVX512())
      return 32;
    return 16;
  }
  return 8;
}

unsigned X86TTI::getRegisterBitWidth(bool Vector) const {
  if (Vector) {
    if (ST->hasAVX512()) return 512;
    if (ST->hasAVX()) return 256;
    if (ST->hasSSE1()) return 128;
    return 0;
  }

  if (ST->is64Bit())
    return 64;
  return 32;

}

unsigned X86TTI::getMaxInterleaveFactor() const {
  if (ST->isAtom())
    return 1;

  // Sandybridge and Haswell have multiple execution ports and pipelined
  // vector units.
  if (ST->hasAVX())
    return 4;

  return 2;
}

unsigned X86TTI::getArithmeticInstrCost(
    unsigned Opcode, Type *Ty, OperandValueKind Op1Info,
    OperandValueKind Op2Info, OperandValueProperties Opd1PropInfo,
    OperandValueProperties Opd2PropInfo) const {
  // Legalize the type.
  std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Ty);

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

  if (ISD == ISD::SDIV &&
      Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
      Opd2PropInfo == TargetTransformInfo::OP_PowerOf2) {
    // On X86, vector signed division by constants power-of-two are
    // normally expanded to the sequence SRA + SRL + ADD + SRA.
    // The OperandValue properties many not be same as that of previous
    // operation;conservatively assume OP_None.
    unsigned Cost =
        2 * getArithmeticInstrCost(Instruction::AShr, Ty, Op1Info, Op2Info,
                                   TargetTransformInfo::OP_None,
                                   TargetTransformInfo::OP_None);
    Cost += getArithmeticInstrCost(Instruction::LShr, Ty, Op1Info, Op2Info,
                                   TargetTransformInfo::OP_None,
                                   TargetTransformInfo::OP_None);
    Cost += getArithmeticInstrCost(Instruction::Add, Ty, Op1Info, Op2Info,
                                   TargetTransformInfo::OP_None,
                                   TargetTransformInfo::OP_None);

    return Cost;
  }

  static const CostTblEntry<MVT::SimpleValueType>
  AVX2UniformConstCostTable[] = {
    { ISD::SDIV, MVT::v16i16,  6 }, // vpmulhw sequence
    { ISD::UDIV, MVT::v16i16,  6 }, // vpmulhuw sequence
    { ISD::SDIV, MVT::v8i32,  15 }, // vpmuldq sequence
    { ISD::UDIV, MVT::v8i32,  15 }, // vpmuludq sequence
  };

  if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
      ST->hasAVX2()) {
    int Idx = CostTableLookup(AVX2UniformConstCostTable, ISD, LT.second);
    if (Idx != -1)
      return LT.first * AVX2UniformConstCostTable[Idx].Cost;
  }

  static const CostTblEntry<MVT::SimpleValueType> AVX2CostTable[] = {
    // Shifts on v4i64/v8i32 on AVX2 is legal even though we declare to
    // customize them to detect the cases where shift amount is a scalar one.
    { ISD::SHL,     MVT::v4i32,    1 },
    { ISD::SRL,     MVT::v4i32,    1 },
    { ISD::SRA,     MVT::v4i32,    1 },
    { ISD::SHL,     MVT::v8i32,    1 },
    { ISD::SRL,     MVT::v8i32,    1 },
    { ISD::SRA,     MVT::v8i32,    1 },
    { ISD::SHL,     MVT::v2i64,    1 },
    { ISD::SRL,     MVT::v2i64,    1 },
    { ISD::SHL,     MVT::v4i64,    1 },
    { ISD::SRL,     MVT::v4i64,    1 },

    { ISD::SHL,  MVT::v32i8,  42 }, // cmpeqb sequence.
    { ISD::SHL,  MVT::v16i16,  16*10 }, // Scalarized.

    { ISD::SRL,  MVT::v32i8,  32*10 }, // Scalarized.
    { ISD::SRL,  MVT::v16i16,  8*10 }, // Scalarized.

    { ISD::SRA,  MVT::v32i8,  32*10 }, // Scalarized.
    { ISD::SRA,  MVT::v16i16,  16*10 }, // Scalarized.
    { ISD::SRA,  MVT::v4i64,  4*10 }, // Scalarized.

    // Vectorizing division is a bad idea. See the SSE2 table for more comments.
    { ISD::SDIV,  MVT::v32i8,  32*20 },
    { ISD::SDIV,  MVT::v16i16, 16*20 },
    { ISD::SDIV,  MVT::v8i32,  8*20 },
    { ISD::SDIV,  MVT::v4i64,  4*20 },
    { ISD::UDIV,  MVT::v32i8,  32*20 },
    { ISD::UDIV,  MVT::v16i16, 16*20 },
    { ISD::UDIV,  MVT::v8i32,  8*20 },
    { ISD::UDIV,  MVT::v4i64,  4*20 },
  };

  // Look for AVX2 lowering tricks.
  if (ST->hasAVX2()) {
    if (ISD == ISD::SHL && LT.second == MVT::v16i16 &&
        (Op2Info == TargetTransformInfo::OK_UniformConstantValue ||
         Op2Info == TargetTransformInfo::OK_NonUniformConstantValue))
      // On AVX2, a packed v16i16 shift left by a constant build_vector
      // is lowered into a vector multiply (vpmullw).
      return LT.first;

    int Idx = CostTableLookup(AVX2CostTable, ISD, LT.second);
    if (Idx != -1)
      return LT.first * AVX2CostTable[Idx].Cost;
  }

  static const CostTblEntry<MVT::SimpleValueType>
  SSE2UniformConstCostTable[] = {
    // We don't correctly identify costs of casts because they are marked as
    // custom.
    // Constant splats are cheaper for the following instructions.
    { ISD::SHL,  MVT::v16i8,  1 }, // psllw.
    { ISD::SHL,  MVT::v8i16,  1 }, // psllw.
    { ISD::SHL,  MVT::v4i32,  1 }, // pslld
    { ISD::SHL,  MVT::v2i64,  1 }, // psllq.

    { ISD::SRL,  MVT::v16i8,  1 }, // psrlw.
    { ISD::SRL,  MVT::v8i16,  1 }, // psrlw.
    { ISD::SRL,  MVT::v4i32,  1 }, // psrld.
    { ISD::SRL,  MVT::v2i64,  1 }, // psrlq.

    { ISD::SRA,  MVT::v16i8,  4 }, // psrlw, pand, pxor, psubb.
    { ISD::SRA,  MVT::v8i16,  1 }, // psraw.
    { ISD::SRA,  MVT::v4i32,  1 }, // psrad.

    { ISD::SDIV, MVT::v8i16,  6 }, // pmulhw sequence
    { ISD::UDIV, MVT::v8i16,  6 }, // pmulhuw sequence
    { ISD::SDIV, MVT::v4i32, 19 }, // pmuludq sequence
    { ISD::UDIV, MVT::v4i32, 15 }, // pmuludq sequence
  };

  if (Op2Info == TargetTransformInfo::OK_UniformConstantValue &&
      ST->hasSSE2()) {
    // pmuldq sequence.
    if (ISD == ISD::SDIV && LT.second == MVT::v4i32 && ST->hasSSE41())
      return LT.first * 15;

    int Idx = CostTableLookup(SSE2UniformConstCostTable, ISD, LT.second);
    if (Idx != -1)
      return LT.first * SSE2UniformConstCostTable[Idx].Cost;
  }

  if (ISD == ISD::SHL &&
      Op2Info == TargetTransformInfo::OK_NonUniformConstantValue) {
    EVT VT = LT.second;
    if ((VT == MVT::v8i16 && ST->hasSSE2()) ||
        (VT == MVT::v4i32 && ST->hasSSE41()))
      // Vector shift left by non uniform constant can be lowered
      // into vector multiply (pmullw/pmulld).
      return LT.first;
    if (VT == MVT::v4i32 && ST->hasSSE2())
      // A vector shift left by non uniform constant is converted
      // into a vector multiply; the new multiply is eventually
      // lowered into a sequence of shuffles and 2 x pmuludq.
      ISD = ISD::MUL;
  }

  static const CostTblEntry<MVT::SimpleValueType> SSE2CostTable[] = {
    // We don't correctly identify costs of casts because they are marked as
    // custom.
    // For some cases, where the shift amount is a scalar we would be able
    // to generate better code. Unfortunately, when this is the case the value
    // (the splat) will get hoisted out of the loop, thereby making it invisible
    // to ISel. The cost model must return worst case assumptions because it is
    // used for vectorization and we don't want to make vectorized code worse
    // than scalar code.
    { ISD::SHL,  MVT::v16i8,  30 }, // cmpeqb sequence.
    { ISD::SHL,  MVT::v8i16,  8*10 }, // Scalarized.
    { ISD::SHL,  MVT::v4i32,  2*5 }, // We optimized this using mul.
    { ISD::SHL,  MVT::v2i64,  2*10 }, // Scalarized.
    { ISD::SHL,  MVT::v4i64,  4*10 }, // Scalarized. 

    { ISD::SRL,  MVT::v16i8,  16*10 }, // Scalarized.
    { ISD::SRL,  MVT::v8i16,  8*10 }, // Scalarized.
    { ISD::SRL,  MVT::v4i32,  4*10 }, // Scalarized.
    { ISD::SRL,  MVT::v2i64,  2*10 }, // Scalarized.

    { ISD::SRA,  MVT::v16i8,  16*10 }, // Scalarized.
    { ISD::SRA,  MVT::v8i16,  8*10 }, // Scalarized.
    { ISD::SRA,  MVT::v4i32,  4*10 }, // Scalarized.
    { ISD::SRA,  MVT::v2i64,  2*10 }, // Scalarized.

    // It is not a good idea to vectorize division. We have to scalarize it and
    // in the process we will often end up having to spilling regular
    // registers. The overhead of division is going to dominate most kernels
    // anyways so try hard to prevent vectorization of division - it is
    // generally a bad idea. Assume somewhat arbitrarily that we have to be able
    // to hide "20 cycles" for each lane.
    { ISD::SDIV,  MVT::v16i8,  16*20 },
    { ISD::SDIV,  MVT::v8i16,  8*20 },
    { ISD::SDIV,  MVT::v4i32,  4*20 },
    { ISD::SDIV,  MVT::v2i64,  2*20 },
    { ISD::UDIV,  MVT::v16i8,  16*20 },
    { ISD::UDIV,  MVT::v8i16,  8*20 },
    { ISD::UDIV,  MVT::v4i32,  4*20 },
    { ISD::UDIV,  MVT::v2i64,  2*20 },
  };

  if (ST->hasSSE2()) {
    int Idx = CostTableLookup(SSE2CostTable, ISD, LT.second);
    if (Idx != -1)
      return LT.first * SSE2CostTable[Idx].Cost;
  }

  static const CostTblEntry<MVT::SimpleValueType> AVX1CostTable[] = {
    // We don't have to scalarize unsupported ops. We can issue two half-sized
    // operations and we only need to extract the upper YMM half.
    // Two ops + 1 extract + 1 insert = 4.
    { ISD::MUL,     MVT::v16i16,   4 },
    { ISD::MUL,     MVT::v8i32,    4 },
    { ISD::SUB,     MVT::v8i32,    4 },
    { ISD::ADD,     MVT::v8i32,    4 },
    { ISD::SUB,     MVT::v4i64,    4 },
    { ISD::ADD,     MVT::v4i64,    4 },
    // A v4i64 multiply is custom lowered as two split v2i64 vectors that then
    // are lowered as a series of long multiplies(3), shifts(4) and adds(2)
    // Because we believe v4i64 to be a legal type, we must also include the
    // split factor of two in the cost table. Therefore, the cost here is 18
    // instead of 9.
    { ISD::MUL,     MVT::v4i64,    18 },
  };

  // Look for AVX1 lowering tricks.
  if (ST->hasAVX() && !ST->hasAVX2()) {
    EVT VT = LT.second;

    // v16i16 and v8i32 shifts by non-uniform constants are lowered into a
    // sequence of extract + two vector multiply + insert.
    if (ISD == ISD::SHL && (VT == MVT::v8i32 || VT == MVT::v16i16) &&
        Op2Info == TargetTransformInfo::OK_NonUniformConstantValue)
      ISD = ISD::MUL;

    int Idx = CostTableLookup(AVX1CostTable, ISD, VT);
    if (Idx != -1)
      return LT.first * AVX1CostTable[Idx].Cost;
  }

  // Custom lowering of vectors.
  static const CostTblEntry<MVT::SimpleValueType> CustomLowered[] = {
    // A v2i64/v4i64 and multiply is custom lowered as a series of long
    // multiplies(3), shifts(4) and adds(2).
    { ISD::MUL,     MVT::v2i64,    9 },
    { ISD::MUL,     MVT::v4i64,    9 },
  };
  int Idx = CostTableLookup(CustomLowered, ISD, LT.second);
  if (Idx != -1)
    return LT.first * CustomLowered[Idx].Cost;

  // Special lowering of v4i32 mul on sse2, sse3: Lower v4i32 mul as 2x shuffle,
  // 2x pmuludq, 2x shuffle.
  if (ISD == ISD::MUL && LT.second == MVT::v4i32 && ST->hasSSE2() &&
      !ST->hasSSE41())
    return LT.first * 6;

  // Fallback to the default implementation.
  return TargetTransformInfo::getArithmeticInstrCost(Opcode, Ty, Op1Info,
                                                     Op2Info);
}

unsigned X86TTI::getShuffleCost(ShuffleKind Kind, Type *Tp, int Index,
                                Type *SubTp) const {
  // We only estimate the cost of reverse and alternate shuffles.
  if (Kind != SK_Reverse && Kind != SK_Alternate)
    return TargetTransformInfo::getShuffleCost(Kind, Tp, Index, SubTp);

  if (Kind == SK_Reverse) {
    std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);
    unsigned Cost = 1;
    if (LT.second.getSizeInBits() > 128)
      Cost = 3; // Extract + insert + copy.

    // Multiple by the number of parts.
    return Cost * LT.first;
  }

  if (Kind == SK_Alternate) {
    // 64-bit packed float vectors (v2f32) are widened to type v4f32.
    // 64-bit packed integer vectors (v2i32) are promoted to type v2i64.
    std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Tp);

    // The backend knows how to generate a single VEX.256 version of
    // instruction VPBLENDW if the target supports AVX2.
    if (ST->hasAVX2() && LT.second == MVT::v16i16)
      return LT.first;

    static const CostTblEntry<MVT::SimpleValueType> AVXAltShuffleTbl[] = {
      {ISD::VECTOR_SHUFFLE, MVT::v4i64, 1},  // vblendpd
      {ISD::VECTOR_SHUFFLE, MVT::v4f64, 1},  // vblendpd

      {ISD::VECTOR_SHUFFLE, MVT::v8i32, 1},  // vblendps
      {ISD::VECTOR_SHUFFLE, MVT::v8f32, 1},  // vblendps

      // This shuffle is custom lowered into a sequence of:
      //  2x  vextractf128 , 2x vpblendw , 1x vinsertf128
      {ISD::VECTOR_SHUFFLE, MVT::v16i16, 5},

      // This shuffle is custom lowered into a long sequence of:
      //  2x vextractf128 , 4x vpshufb , 2x vpor ,  1x vinsertf128
      {ISD::VECTOR_SHUFFLE, MVT::v32i8, 9}
    };

    if (ST->hasAVX()) {
      int Idx = CostTableLookup(AVXAltShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
      if (Idx != -1)
        return LT.first * AVXAltShuffleTbl[Idx].Cost;
    }

    static const CostTblEntry<MVT::SimpleValueType> SSE41AltShuffleTbl[] = {
      // These are lowered into movsd.
      {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},
      {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},

      // packed float vectors with four elements are lowered into BLENDI dag
      // nodes. A v4i32/v4f32 BLENDI generates a single 'blendps'/'blendpd'.
      {ISD::VECTOR_SHUFFLE, MVT::v4i32, 1},
      {ISD::VECTOR_SHUFFLE, MVT::v4f32, 1},

      // This shuffle generates a single pshufw.
      {ISD::VECTOR_SHUFFLE, MVT::v8i16, 1},

      // There is no instruction that matches a v16i8 alternate shuffle.
      // The backend will expand it into the sequence 'pshufb + pshufb + or'.
      {ISD::VECTOR_SHUFFLE, MVT::v16i8, 3}
    };

    if (ST->hasSSE41()) {
      int Idx = CostTableLookup(SSE41AltShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
      if (Idx != -1)
        return LT.first * SSE41AltShuffleTbl[Idx].Cost;
    }

    static const CostTblEntry<MVT::SimpleValueType> SSSE3AltShuffleTbl[] = {
      {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},  // movsd
      {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},  // movsd

      // SSE3 doesn't have 'blendps'. The following shuffles are expanded into
      // the sequence 'shufps + pshufd'
      {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2},
      {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2},

      {ISD::VECTOR_SHUFFLE, MVT::v8i16, 3}, // pshufb + pshufb + or
      {ISD::VECTOR_SHUFFLE, MVT::v16i8, 3}  // pshufb + pshufb + or
    };
 
    if (ST->hasSSSE3()) {
      int Idx = CostTableLookup(SSSE3AltShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
      if (Idx != -1)
        return LT.first * SSSE3AltShuffleTbl[Idx].Cost;
    }

    static const CostTblEntry<MVT::SimpleValueType> SSEAltShuffleTbl[] = {
      {ISD::VECTOR_SHUFFLE, MVT::v2i64, 1},  // movsd
      {ISD::VECTOR_SHUFFLE, MVT::v2f64, 1},  // movsd

      {ISD::VECTOR_SHUFFLE, MVT::v4i32, 2}, // shufps + pshufd
      {ISD::VECTOR_SHUFFLE, MVT::v4f32, 2}, // shufps + pshufd
 
      // This is expanded into a long sequence of four extract + four insert.
      {ISD::VECTOR_SHUFFLE, MVT::v8i16, 8}, // 4 x pextrw + 4 pinsrw.

      // 8 x (pinsrw + pextrw + and + movb + movzb + or)
      {ISD::VECTOR_SHUFFLE, MVT::v16i8, 48}
    };

    // Fall-back (SSE3 and SSE2). 
    int Idx = CostTableLookup(SSEAltShuffleTbl, ISD::VECTOR_SHUFFLE, LT.second);
    if (Idx != -1)
      return LT.first * SSEAltShuffleTbl[Idx].Cost;
    return TargetTransformInfo::getShuffleCost(Kind, Tp, Index, SubTp);
  }

  return TargetTransformInfo::getShuffleCost(Kind, Tp, Index, SubTp);
}

unsigned X86TTI::getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src) const {
  int ISD = TLI->InstructionOpcodeToISD(Opcode);
  assert(ISD && "Invalid opcode");

  std::pair<unsigned, MVT> LTSrc = TLI->getTypeLegalizationCost(Src);
  std::pair<unsigned, MVT> LTDest = TLI->getTypeLegalizationCost(Dst);

  static const TypeConversionCostTblEntry<MVT::SimpleValueType>
  SSE2ConvTbl[] = {
    // These are somewhat magic numbers justified by looking at the output of
    // Intel's IACA, running some kernels and making sure when we take
    // legalization into account the throughput will be overestimated.
    { ISD::UINT_TO_FP, MVT::v2f64, MVT::v2i64, 2*10 },
    { ISD::UINT_TO_FP, MVT::v2f64, MVT::v4i32, 4*10 },
    { ISD::UINT_TO_FP, MVT::v2f64, MVT::v8i16, 8*10 },
    { ISD::UINT_TO_FP, MVT::v2f64, MVT::v16i8, 16*10 },
    { ISD::SINT_TO_FP, MVT::v2f64, MVT::v2i64, 2*10 },
    { ISD::SINT_TO_FP, MVT::v2f64, MVT::v4i32, 4*10 },
    { ISD::SINT_TO_FP, MVT::v2f64, MVT::v8i16, 8*10 },
    { ISD::SINT_TO_FP, MVT::v2f64, MVT::v16i8, 16*10 },
    // There are faster sequences for float conversions.
    { ISD::UINT_TO_FP, MVT::v4f32, MVT::v2i64, 15 },
    { ISD::UINT_TO_FP, MVT::v4f32, MVT::v4i32, 15 },
    { ISD::UINT_TO_FP, MVT::v4f32, MVT::v8i16, 15 },
    { ISD::UINT_TO_FP, MVT::v4f32, MVT::v16i8, 8 },
    { ISD::SINT_TO_FP, MVT::v4f32, MVT::v2i64, 15 },
    { ISD::SINT_TO_FP, MVT::v4f32, MVT::v4i32, 15 },
    { ISD::SINT_TO_FP, MVT::v4f32, MVT::v8i16, 15 },
    { ISD::SINT_TO_FP, MVT::v4f32, MVT::v16i8, 8 },
  };

  if (ST->hasSSE2() && !ST->hasAVX()) {
    int Idx =
        ConvertCostTableLookup(SSE2ConvTbl, ISD, LTDest.second, LTSrc.second);
    if (Idx != -1)
      return LTSrc.first * SSE2ConvTbl[Idx].Cost;
  }

  EVT SrcTy = TLI->getValueType(Src);
  EVT DstTy = TLI->getValueType(Dst);

  // The function getSimpleVT only handles simple value types.
  if (!SrcTy.isSimple() || !DstTy.isSimple())
    return TargetTransformInfo::getCastInstrCost(Opcode, Dst, Src);

  static const TypeConversionCostTblEntry<MVT::SimpleValueType>
  AVX2ConversionTbl[] = {
    { ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8,  1 },
    { ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8,  1 },
    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i1,   3 },
    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i1,   3 },
    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i8,   3 },
    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i8,   3 },
    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i16,  1 },
    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i16,  1 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i1,   3 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i1,   3 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i8,   3 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i8,   3 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i16,  3 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i16,  3 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i32,  1 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i32,  1 },

    { ISD::TRUNCATE,    MVT::v4i8,   MVT::v4i64,  2 },
    { ISD::TRUNCATE,    MVT::v4i16,  MVT::v4i64,  2 },
    { ISD::TRUNCATE,    MVT::v4i32,  MVT::v4i64,  2 },
    { ISD::TRUNCATE,    MVT::v8i8,   MVT::v8i32,  2 },
    { ISD::TRUNCATE,    MVT::v8i16,  MVT::v8i32,  2 },
    { ISD::TRUNCATE,    MVT::v8i32,  MVT::v8i64,  4 },
  };

  static const TypeConversionCostTblEntry<MVT::SimpleValueType>
  AVXConversionTbl[] = {
    { ISD::SIGN_EXTEND, MVT::v16i16, MVT::v16i8, 4 },
    { ISD::ZERO_EXTEND, MVT::v16i16, MVT::v16i8, 4 },
    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i1,  7 },
    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i1,  4 },
    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i8,  7 },
    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i8,  4 },
    { ISD::SIGN_EXTEND, MVT::v8i32,  MVT::v8i16, 4 },
    { ISD::ZERO_EXTEND, MVT::v8i32,  MVT::v8i16, 4 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i1,  6 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i1,  4 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i8,  6 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i8,  4 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i16, 6 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i16, 3 },
    { ISD::SIGN_EXTEND, MVT::v4i64,  MVT::v4i32, 4 },
    { ISD::ZERO_EXTEND, MVT::v4i64,  MVT::v4i32, 4 },

    { ISD::TRUNCATE,    MVT::v4i8,  MVT::v4i64,  4 },
    { ISD::TRUNCATE,    MVT::v4i16, MVT::v4i64,  4 },
    { ISD::TRUNCATE,    MVT::v4i32, MVT::v4i64,  4 },
    { ISD::TRUNCATE,    MVT::v8i8,  MVT::v8i32,  4 },
    { ISD::TRUNCATE,    MVT::v8i16, MVT::v8i32,  5 },
    { ISD::TRUNCATE,    MVT::v16i8, MVT::v16i16, 4 },
    { ISD::TRUNCATE,    MVT::v8i32, MVT::v8i64,  9 },

    { ISD::SINT_TO_FP,  MVT::v8f32, MVT::v8i1,  8 },
    { ISD::SINT_TO_FP,  MVT::v8f32, MVT::v8i8,  8 },
    { ISD::SINT_TO_FP,  MVT::v8f32, MVT::v8i16, 5 },
    { ISD::SINT_TO_FP,  MVT::v8f32, MVT::v8i32, 1 },
    { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i1,  3 },
    { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i8,  3 },
    { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i16, 3 },
    { ISD::SINT_TO_FP,  MVT::v4f32, MVT::v4i32, 1 },
    { ISD::SINT_TO_FP,  MVT::v4f64, MVT::v4i1,  3 },
    { ISD::SINT_TO_FP,  MVT::v4f64, MVT::v4i8,  3 },
    { ISD::SINT_TO_FP,  MVT::v4f64, MVT::v4i16, 3 },
    { ISD::SINT_TO_FP,  MVT::v4f64, MVT::v4i32, 1 },

    { ISD::UINT_TO_FP,  MVT::v8f32, MVT::v8i1,  6 },
    { ISD::UINT_TO_FP,  MVT::v8f32, MVT::v8i8,  5 },
    { ISD::UINT_TO_FP,  MVT::v8f32, MVT::v8i16, 5 },
    { ISD::UINT_TO_FP,  MVT::v8f32, MVT::v8i32, 9 },
    { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i1,  7 },
    { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i8,  2 },
    { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i16, 2 },
    { ISD::UINT_TO_FP,  MVT::v4f32, MVT::v4i32, 6 },
    { ISD::UINT_TO_FP,  MVT::v4f64, MVT::v4i1,  7 },
    { ISD::UINT_TO_FP,  MVT::v4f64, MVT::v4i8,  2 },
    { ISD::UINT_TO_FP,  MVT::v4f64, MVT::v4i16, 2 },
    { ISD::UINT_TO_FP,  MVT::v4f64, MVT::v4i32, 6 },
    // The generic code to compute the scalar overhead is currently broken.
    // Workaround this limitation by estimating the scalarization overhead
    // here. We have roughly 10 instructions per scalar element.
    // Multiply that by the vector width.
    // FIXME: remove that when PR19268 is fixed.
    { ISD::UINT_TO_FP,  MVT::v2f64, MVT::v2i64, 2*10 },
    { ISD::UINT_TO_FP,  MVT::v4f64, MVT::v4i64, 4*10 },

    { ISD::FP_TO_SINT,  MVT::v8i8,  MVT::v8f32, 7 },
    { ISD::FP_TO_SINT,  MVT::v4i8,  MVT::v4f32, 1 },
    // This node is expanded into scalarized operations but BasicTTI is overly
    // optimistic estimating its cost.  It computes 3 per element (one
    // vector-extract, one scalar conversion and one vector-insert).  The
    // problem is that the inserts form a read-modify-write chain so latency
    // should be factored in too.  Inflating the cost per element by 1.
    { ISD::FP_TO_UINT,  MVT::v8i32, MVT::v8f32, 8*4 },
    { ISD::FP_TO_UINT,  MVT::v4i32, MVT::v4f64, 4*4 },
  };

  if (ST->hasAVX2()) {
    int Idx = ConvertCostTableLookup(AVX2ConversionTbl, ISD,
                                     DstTy.getSimpleVT(), SrcTy.getSimpleVT());
    if (Idx != -1)
      return AVX2ConversionTbl[Idx].Cost;
  }

  if (ST->hasAVX()) {
    int Idx = ConvertCostTableLookup(AVXConversionTbl, ISD, DstTy.getSimpleVT(),
                                     SrcTy.getSimpleVT());
    if (Idx != -1)
      return AVXConversionTbl[Idx].Cost;
  }

  return TargetTransformInfo::getCastInstrCost(Opcode, Dst, Src);
}

unsigned X86TTI::getCmpSelInstrCost(unsigned Opcode, Type *ValTy,
                                    Type *CondTy) const {
  // Legalize the type.
  std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(ValTy);

  MVT MTy = LT.second;

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

  static const CostTblEntry<MVT::SimpleValueType> SSE42CostTbl[] = {
    { ISD::SETCC,   MVT::v2f64,   1 },
    { ISD::SETCC,   MVT::v4f32,   1 },
    { ISD::SETCC,   MVT::v2i64,   1 },
    { ISD::SETCC,   MVT::v4i32,   1 },
    { ISD::SETCC,   MVT::v8i16,   1 },
    { ISD::SETCC,   MVT::v16i8,   1 },
  };

  static const CostTblEntry<MVT::SimpleValueType> AVX1CostTbl[] = {
    { ISD::SETCC,   MVT::v4f64,   1 },
    { ISD::SETCC,   MVT::v8f32,   1 },
    // AVX1 does not support 8-wide integer compare.
    { ISD::SETCC,   MVT::v4i64,   4 },
    { ISD::SETCC,   MVT::v8i32,   4 },
    { ISD::SETCC,   MVT::v16i16,  4 },
    { ISD::SETCC,   MVT::v32i8,   4 },
  };

  static const CostTblEntry<MVT::SimpleValueType> AVX2CostTbl[] = {
    { ISD::SETCC,   MVT::v4i64,   1 },
    { ISD::SETCC,   MVT::v8i32,   1 },
    { ISD::SETCC,   MVT::v16i16,  1 },
    { ISD::SETCC,   MVT::v32i8,   1 },
  };

  if (ST->hasAVX2()) {
    int Idx = CostTableLookup(AVX2CostTbl, ISD, MTy);
    if (Idx != -1)
      return LT.first * AVX2CostTbl[Idx].Cost;
  }

  if (ST->hasAVX()) {
    int Idx = CostTableLookup(AVX1CostTbl, ISD, MTy);
    if (Idx != -1)
      return LT.first * AVX1CostTbl[Idx].Cost;
  }

  if (ST->hasSSE42()) {
    int Idx = CostTableLookup(SSE42CostTbl, ISD, MTy);
    if (Idx != -1)
      return LT.first * SSE42CostTbl[Idx].Cost;
  }

  return TargetTransformInfo::getCmpSelInstrCost(Opcode, ValTy, CondTy);
}

unsigned X86TTI::getVectorInstrCost(unsigned Opcode, Type *Val,
                                    unsigned Index) const {
  assert(Val->isVectorTy() && "This must be a vector type");

  if (Index != -1U) {
    // Legalize the type.
    std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Val);

    // This type is legalized to a scalar type.
    if (!LT.second.isVector())
      return 0;

    // The type may be split. Normalize the index to the new type.
    unsigned Width = LT.second.getVectorNumElements();
    Index = Index % Width;

    // Floating point scalars are already located in index #0.
    if (Val->getScalarType()->isFloatingPointTy() && Index == 0)
      return 0;
  }

  return TargetTransformInfo::getVectorInstrCost(Opcode, Val, Index);
}

unsigned X86TTI::getScalarizationOverhead(Type *Ty, bool Insert,
                                            bool Extract) const {
  assert (Ty->isVectorTy() && "Can only scalarize vectors");
  unsigned Cost = 0;

  for (int i = 0, e = Ty->getVectorNumElements(); i < e; ++i) {
    if (Insert)
      Cost += TopTTI->getVectorInstrCost(Instruction::InsertElement, Ty, i);
    if (Extract)
      Cost += TopTTI->getVectorInstrCost(Instruction::ExtractElement, Ty, i);
  }

  return Cost;
}

unsigned X86TTI::getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
                                 unsigned AddressSpace) const {
  // Handle non-power-of-two vectors such as <3 x float>
  if (VectorType *VTy = dyn_cast<VectorType>(Src)) {
    unsigned NumElem = VTy->getVectorNumElements();

    // Handle a few common cases:
    // <3 x float>
    if (NumElem == 3 && VTy->getScalarSizeInBits() == 32)
      // Cost = 64 bit store + extract + 32 bit store.
      return 3;

    // <3 x double>
    if (NumElem == 3 && VTy->getScalarSizeInBits() == 64)
      // Cost = 128 bit store + unpack + 64 bit store.
      return 3;

    // Assume that all other non-power-of-two numbers are scalarized.
    if (!isPowerOf2_32(NumElem)) {
      unsigned Cost = TargetTransformInfo::getMemoryOpCost(Opcode,
                                                           VTy->getScalarType(),
                                                           Alignment,
                                                           AddressSpace);
      unsigned SplitCost = getScalarizationOverhead(Src,
                                                    Opcode == Instruction::Load,
                                                    Opcode==Instruction::Store);
      return NumElem * Cost + SplitCost;
    }
  }

  // Legalize the type.
  std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(Src);
  assert((Opcode == Instruction::Load || Opcode == Instruction::Store) &&
         "Invalid Opcode");

  // Each load/store unit costs 1.
  unsigned Cost = LT.first * 1;

  // On Sandybridge 256bit load/stores are double pumped
  // (but not on Haswell).
  if (LT.second.getSizeInBits() > 128 && !ST->hasAVX2())
    Cost*=2;

  return Cost;
}

unsigned X86TTI::getAddressComputationCost(Type *Ty, bool IsComplex) const {
  // Address computations in vectorized code with non-consecutive addresses will
  // likely result in more instructions compared to scalar code where the
  // computation can more often be merged into the index mode. The resulting
  // extra micro-ops can significantly decrease throughput.
  unsigned NumVectorInstToHideOverhead = 10;

  if (Ty->isVectorTy() && IsComplex)
    return NumVectorInstToHideOverhead;

  return TargetTransformInfo::getAddressComputationCost(Ty, IsComplex);
}

unsigned X86TTI::getReductionCost(unsigned Opcode, Type *ValTy,
                                  bool IsPairwise) const {
  
  std::pair<unsigned, MVT> LT = TLI->getTypeLegalizationCost(ValTy);
  
  MVT MTy = LT.second;
  
  int ISD = TLI->InstructionOpcodeToISD(Opcode);
  assert(ISD && "Invalid opcode");
 
  // We use the Intel Architecture Code Analyzer(IACA) to measure the throughput 
  // and make it as the cost. 
 
  static const CostTblEntry<MVT::SimpleValueType> SSE42CostTblPairWise[] = {
    { ISD::FADD,  MVT::v2f64,   2 },
    { ISD::FADD,  MVT::v4f32,   4 },
    { ISD::ADD,   MVT::v2i64,   2 },      // The data reported by the IACA tool is "1.6".
    { ISD::ADD,   MVT::v4i32,   3 },      // The data reported by the IACA tool is "3.5".
    { ISD::ADD,   MVT::v8i16,   5 },
  };
 
  static const CostTblEntry<MVT::SimpleValueType> AVX1CostTblPairWise[] = {
    { ISD::FADD,  MVT::v4f32,   4 },
    { ISD::FADD,  MVT::v4f64,   5 },
    { ISD::FADD,  MVT::v8f32,   7 },
    { ISD::ADD,   MVT::v2i64,   1 },      // The data reported by the IACA tool is "1.5".
    { ISD::ADD,   MVT::v4i32,   3 },      // The data reported by the IACA tool is "3.5".
    { ISD::ADD,   MVT::v4i64,   5 },      // The data reported by the IACA tool is "4.8".
    { ISD::ADD,   MVT::v8i16,   5 },
    { ISD::ADD,   MVT::v8i32,   5 },
  };

  static const CostTblEntry<MVT::SimpleValueType> SSE42CostTblNoPairWise[] = {
    { ISD::FADD,  MVT::v2f64,   2 },
    { ISD::FADD,  MVT::v4f32,   4 },
    { ISD::ADD,   MVT::v2i64,   2 },      // The data reported by the IACA tool is "1.6".
    { ISD::ADD,   MVT::v4i32,   3 },      // The data reported by the IACA tool is "3.3".
    { ISD::ADD,   MVT::v8i16,   4 },      // The data reported by the IACA tool is "4.3".
  };
  
  static const CostTblEntry<MVT::SimpleValueType> AVX1CostTblNoPairWise[] = {
    { ISD::FADD,  MVT::v4f32,   3 },
    { ISD::FADD,  MVT::v4f64,   3 },
    { ISD::FADD,  MVT::v8f32,   4 },
    { ISD::ADD,   MVT::v2i64,   1 },      // The data reported by the IACA tool is "1.5".
    { ISD::ADD,   MVT::v4i32,   3 },      // The data reported by the IACA tool is "2.8".
    { ISD::ADD,   MVT::v4i64,   3 },
    { ISD::ADD,   MVT::v8i16,   4 },
    { ISD::ADD,   MVT::v8i32,   5 },
  };
  
  if (IsPairwise) {
    if (ST->hasAVX()) {
      int Idx = CostTableLookup(AVX1CostTblPairWise, ISD, MTy);
      if (Idx != -1)
        return LT.first * AVX1CostTblPairWise[Idx].Cost;
    }
  
    if (ST->hasSSE42()) {
      int Idx = CostTableLookup(SSE42CostTblPairWise, ISD, MTy);
      if (Idx != -1)
        return LT.first * SSE42CostTblPairWise[Idx].Cost;
    }
  } else {
    if (ST->hasAVX()) {
      int Idx = CostTableLookup(AVX1CostTblNoPairWise, ISD, MTy);
      if (Idx != -1)
        return LT.first * AVX1CostTblNoPairWise[Idx].Cost;
    }
    
    if (ST->hasSSE42()) {
      int Idx = CostTableLookup(SSE42CostTblNoPairWise, ISD, MTy);
      if (Idx != -1)
        return LT.first * SSE42CostTblNoPairWise[Idx].Cost;
    }
  }

  return TargetTransformInfo::getReductionCost(Opcode, ValTy, IsPairwise);
}

/// \brief Calculate the cost of materializing a 64-bit value. This helper
/// method might only calculate a fraction of a larger immediate. Therefore it
/// is valid to return a cost of ZERO.
unsigned X86TTI::getIntImmCost(int64_t Val) const {
  if (Val == 0)
    return TCC_Free;

  if (isInt<32>(Val))
    return TCC_Basic;

  return 2 * TCC_Basic;
}

unsigned X86TTI::getIntImmCost(const APInt &Imm, Type *Ty) const {
  assert(Ty->isIntegerTy());

  unsigned BitSize = Ty->getPrimitiveSizeInBits();
  if (BitSize == 0)
    return ~0U;

  // Never hoist constants larger than 128bit, because this might lead to
  // incorrect code generation or assertions in codegen.
  // Fixme: Create a cost model for types larger than i128 once the codegen
  // issues have been fixed.
  if (BitSize > 128)
    return TCC_Free;

  if (Imm == 0)
    return TCC_Free;

  // Sign-extend all constants to a multiple of 64-bit.
  APInt ImmVal = Imm;
  if (BitSize & 0x3f)
    ImmVal = Imm.sext((BitSize + 63) & ~0x3fU);

  // Split the constant into 64-bit chunks and calculate the cost for each
  // chunk.
  unsigned Cost = 0;
  for (unsigned ShiftVal = 0; ShiftVal < BitSize; ShiftVal += 64) {
    APInt Tmp = ImmVal.ashr(ShiftVal).sextOrTrunc(64);
    int64_t Val = Tmp.getSExtValue();
    Cost += getIntImmCost(Val);
  }
  // We need at least one instruction to materialze the constant.
  return std::max(1U, Cost);
}

unsigned X86TTI::getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
                               Type *Ty) const {
  assert(Ty->isIntegerTy());

  unsigned BitSize = Ty->getPrimitiveSizeInBits();
  // There is no cost model for constants with a bit size of 0. Return TCC_Free
  // here, so that constant hoisting will ignore this constant.
  if (BitSize == 0)
    return TCC_Free;

  unsigned ImmIdx = ~0U;
  switch (Opcode) {
  default: return TCC_Free;
  case Instruction::GetElementPtr:
    // Always hoist the base address of a GetElementPtr. This prevents the
    // creation of new constants for every base constant that gets constant
    // folded with the offset.
    if (Idx == 0)
      return 2 * TCC_Basic;
    return TCC_Free;
  case Instruction::Store:
    ImmIdx = 0;
    break;
  case Instruction::Add:
  case Instruction::Sub:
  case Instruction::Mul:
  case Instruction::UDiv:
  case Instruction::SDiv:
  case Instruction::URem:
  case Instruction::SRem:
  case Instruction::And:
  case Instruction::Or:
  case Instruction::Xor:
  case Instruction::ICmp:
    ImmIdx = 1;
    break;
  // Always return TCC_Free for the shift value of a shift instruction.
  case Instruction::Shl:
  case Instruction::LShr:
  case Instruction::AShr:
    if (Idx == 1)
      return TCC_Free;
    break;
  case Instruction::Trunc:
  case Instruction::ZExt:
  case Instruction::SExt:
  case Instruction::IntToPtr:
  case Instruction::PtrToInt:
  case Instruction::BitCast:
  case Instruction::PHI:
  case Instruction::Call:
  case Instruction::Select:
  case Instruction::Ret:
  case Instruction::Load:
    break;
  }

  if (Idx == ImmIdx) {
    unsigned NumConstants = (BitSize + 63) / 64;
    unsigned Cost = X86TTI::getIntImmCost(Imm, Ty);
    return (Cost <= NumConstants * TCC_Basic)
      ? static_cast<unsigned>(TCC_Free)
      : Cost;
  }

  return X86TTI::getIntImmCost(Imm, Ty);
}

unsigned X86TTI::getIntImmCost(Intrinsic::ID IID, unsigned Idx,
                               const APInt &Imm, Type *Ty) const {
  assert(Ty->isIntegerTy());

  unsigned BitSize = Ty->getPrimitiveSizeInBits();
  // There is no cost model for constants with a bit size of 0. Return TCC_Free
  // here, so that constant hoisting will ignore this constant.
  if (BitSize == 0)
    return TCC_Free;

  switch (IID) {
  default: return TCC_Free;
  case Intrinsic::sadd_with_overflow:
  case Intrinsic::uadd_with_overflow:
  case Intrinsic::ssub_with_overflow:
  case Intrinsic::usub_with_overflow:
  case Intrinsic::smul_with_overflow:
  case Intrinsic::umul_with_overflow:
    if ((Idx == 1) && Imm.getBitWidth() <= 64 && isInt<32>(Imm.getSExtValue()))
      return TCC_Free;
    break;
  case Intrinsic::experimental_stackmap:
    if ((Idx < 2) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
      return TCC_Free;
    break;
  case Intrinsic::experimental_patchpoint_void:
  case Intrinsic::experimental_patchpoint_i64:
    if ((Idx < 4) || (Imm.getBitWidth() <= 64 && isInt<64>(Imm.getSExtValue())))
      return TCC_Free;
    break;
  }
  return X86TTI::getIntImmCost(Imm, Ty);
}