lib/Target/ARM/ARMTargetTransformInfo.h

//===- ARMTargetTransformInfo.h - ARM specific TTI --------------*- 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 a TargetTransformInfo::Concept conforming object specific to the
/// ARM 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_ARM_ARMTARGETTRANSFORMINFO_H
#define LLVM_LIB_TARGET_ARM_ARMTARGETTRANSFORMINFO_H

#include "ARM.h"
#include "ARMSubtarget.h"
#include "ARMTargetMachine.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/Analysis/TargetTransformInfo.h"
#include "llvm/CodeGen/BasicTTIImpl.h"
#include "llvm/IR/Constant.h"
#include "llvm/IR/Function.h"
#include "llvm/MC/SubtargetFeature.h"

namespace llvm {

class APInt;
class ARMTargetLowering;
class Instruction;
class Loop;
class SCEV;
class ScalarEvolution;
class Type;
class Value;

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

  friend BaseT;

  const ARMSubtarget *ST;
  const ARMTargetLowering *TLI;

  // Currently the following features are excluded from InlineFeatureWhitelist.
  // ModeThumb, FeatureNoARM, ModeSoftFloat, FeatureVFPOnlySP, FeatureD16
  // Depending on whether they are set or unset, different
  // instructions/registers are available. For example, inlining a callee with
  // -thumb-mode in a caller with +thumb-mode, may cause the assembler to
  // fail if the callee uses ARM only instructions, e.g. in inline asm.
  const FeatureBitset InlineFeatureWhitelist = {
      ARM::FeatureVFP2, ARM::FeatureVFP3, ARM::FeatureNEON, ARM::FeatureThumb2,
      ARM::FeatureFP16, ARM::FeatureVFP4, ARM::FeatureFPARMv8,
      ARM::FeatureFullFP16, ARM::FeatureFP16FML, ARM::FeatureHWDivThumb,
      ARM::FeatureHWDivARM, ARM::FeatureDB, ARM::FeatureV7Clrex,
      ARM::FeatureAcquireRelease, ARM::FeatureSlowFPBrcc,
      ARM::FeaturePerfMon, ARM::FeatureTrustZone, ARM::Feature8MSecExt,
      ARM::FeatureCrypto, ARM::FeatureCRC, ARM::FeatureRAS,
      ARM::FeatureFPAO, ARM::FeatureFuseAES, ARM::FeatureZCZeroing,
      ARM::FeatureProfUnpredicate, ARM::FeatureSlowVGETLNi32,
      ARM::FeatureSlowVDUP32, ARM::FeaturePreferVMOVSR,
      ARM::FeaturePrefISHSTBarrier, ARM::FeatureMuxedUnits,
      ARM::FeatureSlowOddRegister, ARM::FeatureSlowLoadDSubreg,
      ARM::FeatureDontWidenVMOVS, ARM::FeatureExpandMLx,
      ARM::FeatureHasVMLxHazards, ARM::FeatureNEONForFPMovs,
      ARM::FeatureNEONForFP, ARM::FeatureCheckVLDnAlign,
      ARM::FeatureHasSlowFPVMLx, ARM::FeatureVMLxForwarding,
      ARM::FeaturePref32BitThumb, ARM::FeatureAvoidPartialCPSR,
      ARM::FeatureCheapPredicableCPSR, ARM::FeatureAvoidMOVsShOp,
      ARM::FeatureHasRetAddrStack, ARM::FeatureHasNoBranchPredictor,
      ARM::FeatureDSP, ARM::FeatureMP, ARM::FeatureVirtualization,
      ARM::FeatureMClass, ARM::FeatureRClass, ARM::FeatureAClass,
      ARM::FeatureNaClTrap, ARM::FeatureStrictAlign, ARM::FeatureLongCalls,
      ARM::FeatureExecuteOnly, ARM::FeatureReserveR9, ARM::FeatureNoMovt,
      ARM::FeatureNoNegativeImmediates
  };

  const ARMSubtarget *getST() const { return ST; }
  const ARMTargetLowering *getTLI() const { return TLI; }

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

  bool areInlineCompatible(const Function *Caller,
                           const Function *Callee) const;

  bool enableInterleavedAccessVectorization() { return true; }

  bool shouldFavorBackedgeIndex(const Loop *L) const {
    if (L->getHeader()->getParent()->optForSize())
      return false;
    return ST->isMClass() && ST->isThumb2() && L->getNumBlocks() == 1;
  }

  /// Floating-point computation using ARMv8 AArch32 Advanced
  /// SIMD instructions remains unchanged from ARMv7. Only AArch64 SIMD
  /// is IEEE-754 compliant, but it's not covered in this target.
  bool isFPVectorizationPotentiallyUnsafe() {
    return !ST->isTargetDarwin();
  }

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

  int getIntImmCodeSizeCost(unsigned Opcode, unsigned Idx, const APInt &Imm,
                            Type *Ty);

  using BaseT::getIntImmCost;
  int getIntImmCost(const APInt &Imm, Type *Ty);

  int getIntImmCost(unsigned Opcode, unsigned Idx, const APInt &Imm, Type *Ty);

  /// @}

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

  unsigned getNumberOfRegisters(bool Vector) {
    if (Vector) {
      if (ST->hasNEON())
        return 16;
      return 0;
    }

    if (ST->isThumb1Only())
      return 8;
    return 13;
  }

  unsigned getRegisterBitWidth(bool Vector) const {
    if (Vector) {
      if (ST->hasNEON())
        return 128;
      return 0;
    }

    return 32;
  }

  unsigned getMaxInterleaveFactor(unsigned VF) {
    return ST->getMaxInterleaveFactor();
  }

  int getShuffleCost(TTI::ShuffleKind Kind, Type *Tp, int Index, Type *SubTp);

  int getCastInstrCost(unsigned Opcode, Type *Dst, Type *Src,
                       const Instruction *I = nullptr);

  int getCmpSelInstrCost(unsigned Opcode, Type *ValTy, Type *CondTy,
                         const Instruction *I = nullptr);

  int getVectorInstrCost(unsigned Opcode, Type *Val, unsigned Index);

  int getAddressComputationCost(Type *Val, ScalarEvolution *SE,
                                const SCEV *Ptr);

  int getArithmeticInstrCost(
      unsigned Opcode, Type *Ty,
      TTI::OperandValueKind Op1Info = TTI::OK_AnyValue,
      TTI::OperandValueKind Op2Info = TTI::OK_AnyValue,
      TTI::OperandValueProperties Opd1PropInfo = TTI::OP_None,
      TTI::OperandValueProperties Opd2PropInfo = TTI::OP_None,
      ArrayRef<const Value *> Args = ArrayRef<const Value *>());

  int getMemoryOpCost(unsigned Opcode, Type *Src, unsigned Alignment,
                      unsigned AddressSpace, const Instruction *I = nullptr);

  int getInterleavedMemoryOpCost(unsigned Opcode, Type *VecTy, unsigned Factor,
                                 ArrayRef<unsigned> Indices, unsigned Alignment,
                                 unsigned AddressSpace,
                                 bool UseMaskForCond = false,
                                 bool UseMaskForGaps = false);

  void getUnrollingPreferences(Loop *L, ScalarEvolution &SE,
                               TTI::UnrollingPreferences &UP);

  bool shouldBuildLookupTablesForConstant(Constant *C) const {
    // In the ROPI and RWPI relocation models we can't have pointers to global
    // variables or functions in constant data, so don't convert switches to
    // lookup tables if any of the values would need relocation.
    if (ST->isROPI() || ST->isRWPI())
      return !C->needsRelocation();

    return true;
  }
  /// @}
};

} // end namespace llvm

#endif // LLVM_LIB_TARGET_ARM_ARMTARGETTRANSFORMINFO_H