HexagonTargetTransformInfo.h

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//==- HexagonTargetTransformInfo.cpp - Hexagon specific TTI pass -*- C++ -*-==//
//
// 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
//
/// \file
/// This file implements a TargetTransformInfo analysis pass specific to the
/// Hexagon 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.
///
//===----------------------------------------------------------------------===//

#ifndef LLVM_LIB_TARGET_HEXAGON_HEXAGONTARGETTRANSFORMINFO_H
#define LLVM_LIB_TARGET_HEXAGON_HEXAGONTARGETTRANSFORMINFO_H

#include "Hexagon.h"
#include "HexagonSubtarget.h"
#include "HexagonTargetMachine.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/IR/Function.h"

namespace llvm {

class Loop;
class ScalarEvolution;
class User;
class Value;

class HexagonTTIImpl : public BasicTTIImplBase<HexagonTTIImpl> {
  using BaseT = BasicTTIImplBase<HexagonTTIImpl>;
  using TTI = TargetTransformInfo;

  friend BaseT;

  const HexagonSubtarget &ST;
  const HexagonTargetLowering &TLI;

  const HexagonSubtarget *getST() const { return &ST; }
  const HexagonTargetLowering *getTLI() const { return &TLI; }

  bool useHVX() const;
  bool isTypeForHVX(Type *VecTy) const;

  // Returns the number of vector elements of Ty, if Ty is a vector type,
  // or 1 if Ty is a scalar type. It is incorrect to call this function
  // with any other type.
  unsigned getTypeNumElements(Type *Ty) const;

public:
  explicit HexagonTTIImpl(const HexagonTargetMachine *TM, const Function &F)
      : BaseT(TM, F.getParent()->getDataLayout()),
        ST(*TM->getSubtargetImpl(F)), TLI(*ST.getTargetLowering()) {}

  /// \name Scalar TTI Implementations
  /// @{

  TTI::PopcntSupportKind getPopcntSupport(unsigned IntTyWidthInBit) const;

  // The Hexagon target can unroll loops with run-time trip counts.
  void getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
                               TTI::UnrollingPreferences &UP);

  /// Bias LSR towards creating post-increment opportunities.
  bool shouldFavorPostInc() const;

  // L1 cache prefetch.
  unsigned getPrefetchDistance() const override;
  unsigned getCacheLineSize() const override;

  /// @}

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

  unsigned getNumberOfRegisters(bool vector) const;
  unsigned getMaxInterleaveFactor(unsigned VF);
  unsigned getRegisterBitWidth(bool Vector) const;
  unsigned getMinVectorRegisterBitWidth() const;
  unsigned getMinimumVF(unsigned ElemWidth) const;

  bool shouldMaximizeVectorBandwidth(bool OptSize) const {
    return true;
  }
  bool supportsEfficientVectorElementLoadStore() {
    return false;
  }
  bool hasBranchDivergence() {
    return false;
  }
  bool enableAggressiveInterleaving(bool LoopHasReductions) {
    return false;
  }
  bool prefersVectorizedAddressing() {
    return false;
  }
  bool enableInterleavedAccessVectorization() {
    return true;
  }

  unsigned getScalarizationOverhead(Type *Ty, bool Insert, bool Extract);
  unsigned getOperandsScalarizationOverhead(ArrayRef<const Value*> Args,
            unsigned VF);
  unsigned getCallInstrCost(Function *F, Type *RetTy, ArrayRef<Type*> Tys);
  unsigned getIntrinsicInstrCost(Intrinsic::ID ID, Type *RetTy,
            ArrayRef<Value*> Args, FastMathFlags FMF, unsigned VF);
  unsigned getIntrinsicInstrCost(Intrinsic::ID ID, Type *RetTy,
            ArrayRef<Type*> Tys, FastMathFlags FMF,
            unsigned ScalarizationCostPassed = UINT_MAX);
  unsigned getAddressComputationCost(Type *Tp, ScalarEvolution *SE,
            const SCEV *S);
  unsigned getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
            unsigned AddressSpace, const Instruction *I = nullptr);
  unsigned getMaskedMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
            unsigned AddressSpace);
  unsigned getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index,
            Type *SubTp);
  unsigned getGatherScatterOpCost(unsigned Opcode, Type *DataTy, Value *Ptr,
            bool VariableMask, unsigned Alignment);
  unsigned getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy,
            unsigned Factor, ArrayRef<unsigned> Indices, unsigned Alignment,
            unsigned AddressSpace, bool UseMaskForCond = false,
            bool UseMaskForGaps = false);
  unsigned getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
            const Instruction *I);
  unsigned getArithmeticInstrCost(unsigned Opcode, Type *Ty,
            TTI::OperandValueKind Opd1Info = TTI::OK_AnyValue,
            TTI::OperandValueKind Opd2Info = TTI::OK_AnyValue,
            TTI::OperandValueProperties Opd1PropInfo = TTI::OP_None,
            TTI::OperandValueProperties Opd2PropInfo = TTI::OP_None,
            ArrayRef<const Value *> Args = ArrayRef<const Value *>());
  unsigned getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
            const Instruction *I = nullptr);
  unsigned getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index);

  unsigned getCFInstrCost(unsigned Opcode) {
    return 1;
  }

  /// @}

  int getUserCost(const User *U, ArrayRef<const Value *> Operands);

  // Hexagon specific decision to generate a lookup table.
  bool shouldBuildLookupTables() const;
};

} // end namespace llvm
#endif // LLVM_LIB_TARGET_HEXAGON_HEXAGONTARGETTRANSFORMINFO_H