ARMISelLowering.h

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//===- ARMISelLowering.h - ARM DAG Lowering Interface -----------*- 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
//
//===----------------------------------------------------------------------===//
//
// This file defines the interfaces that ARM uses to lower LLVM code into a
// selection DAG.
//
//===----------------------------------------------------------------------===//
 
#ifndef LLVM_LIB_TARGET_ARM_ARMISELLOWERING_H
#define LLVM_LIB_TARGET_ARM_ARMISELLOWERING_H
 
#include "MCTargetDesc/ARMBaseInfo.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/ISDOpcodes.h"
#include "llvm/CodeGen/MachineFunction.h"
#include "llvm/CodeGen/SelectionDAGNodes.h"
#include "llvm/CodeGen/TargetLowering.h"
#include "llvm/CodeGen/ValueTypes.h"
#include "llvm/CodeGenTypes/MachineValueType.h"
#include "llvm/IR/Attributes.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/InlineAsm.h"
#include "llvm/Support/CodeGen.h"
#include <optional>
#include <utility>
 
namespace llvm {
 
class ARMBaseTargetMachine;
class ARMSubtarget;
class DataLayout;
class FastISel;
class FunctionLoweringInfo;
class GlobalValue;
class InstrItineraryData;
class Instruction;
class IRBuilderBase;
class MachineBasicBlock;
class MachineInstr;
class SelectionDAG;
class TargetLibraryInfo;
class TargetMachine;
class TargetRegisterInfo;
class VectorType;
 
  namespace ARM {
  /// Possible values of current rounding mode, which is specified in bits
  /// 23:22 of FPSCR.
  enum Rounding {
    RN = 0,    // Round to Nearest
    RP = 1,    // Round towards Plus infinity
    RM = 2,    // Round towards Minus infinity
    RZ = 3,    // Round towards Zero
    rmMask = 3 // Bit mask selecting rounding mode
  };
 
  // Bit position of rounding mode bits in FPSCR.
  const unsigned RoundingBitsPos = 22;
 
  // Bits of floating-point status. These are NZCV flags, QC bit and cumulative
  // FP exception bits.
  const unsigned FPStatusBits = 0xf800009f;
 
  // Some bits in the FPSCR are not yet defined.  They must be preserved when
  // modifying the contents.
  const unsigned FPReservedBits = 0x00006060;
  } // namespace ARM
 
  /// Define some predicates that are used for node matching.
  namespace ARM {
 
    bool isBitFieldInvertedMask(unsigned v);
 
  } // end namespace ARM
 
  //===--------------------------------------------------------------------===//
  //  ARMTargetLowering - ARM Implementation of the TargetLowering interface
 
  class ARMTargetLowering : public TargetLowering {
    // Copying needed for an outgoing byval argument.
    enum ByValCopyKind {
      // Argument is already in the correct location, no copy needed.
      NoCopy,
      // Argument value is currently in the local stack frame, needs copying to
      // outgoing arguemnt area.
      CopyOnce,
      // Argument value is currently in the outgoing argument area, but not at
      // the correct offset, so needs copying via a temporary in local stack
      // space.
      CopyViaTemp,
    };
 
  public:
    explicit ARMTargetLowering(const TargetMachine &TM,
                               const ARMSubtarget &STI);
 
    const ARMBaseTargetMachine &getTM() const;
 
    unsigned getJumpTableEncoding() const override;
    bool useSoftFloat() const override;
 
    SDValue LowerOperation(SDValue Op, SelectionDAG &DAG) const override;
 
    /// ReplaceNodeResults - Replace the results of node with an illegal result
    /// type with new values built out of custom code.
    void ReplaceNodeResults(SDNode *N, SmallVectorImpl<SDValue>&Results,
                            SelectionDAG &DAG) const override;
 
    bool isSelectSupported(SelectSupportKind Kind) const override {
      // ARM does not support scalar condition selects on vectors.
      return (Kind != ScalarCondVectorVal);
    }
 
    bool isReadOnly(const GlobalValue *GV) const;
 
    /// getSetCCResultType - Return the value type to use for ISD::SETCC.
    EVT getSetCCResultType(const DataLayout &DL, LLVMContext &Context,
                           EVT VT) const override;
 
    MachineBasicBlock *
    EmitInstrWithCustomInserter(MachineInstr &MI,
                                MachineBasicBlock *MBB) const override;
 
    void AdjustInstrPostInstrSelection(MachineInstr &MI,
                                       SDNode *Node) const override;
 
    bool supportKCFIBundles() const override;
 
    MachineInstr *EmitKCFICheck(MachineBasicBlock &MBB,
                                MachineBasicBlock::instr_iterator &MBBI,
                                const TargetInstrInfo *TII) const override;
 
    SDValue PerformCMOVCombine(SDNode *N, SelectionDAG &DAG) const;
    SDValue PerformBRCONDCombine(SDNode *N, SelectionDAG &DAG) const;
    SDValue PerformCMOVToBFICombine(SDNode *N, SelectionDAG &DAG) const;
    SDValue PerformIntrinsicCombine(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue PerformMVEExtCombine(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue PerformMVETruncCombine(SDNode *N, DAGCombinerInfo &DCI) const;
    SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
 
    bool SimplifyDemandedBitsForTargetNode(SDValue Op,
                                           const APInt &OriginalDemandedBits,
                                           const APInt &OriginalDemandedElts,
                                           KnownBits &Known,
                                           TargetLoweringOpt &TLO,
                                           unsigned Depth) const override;
 
    bool isDesirableToTransformToIntegerOp(unsigned Opc, EVT VT) const override;
 
    /// allowsMisalignedMemoryAccesses - Returns true if the target allows
    /// unaligned memory accesses of the specified type. Returns whether it
    /// is "fast" by reference in the second argument.
    bool allowsMisalignedMemoryAccesses(EVT VT, unsigned AddrSpace,
                                        Align Alignment,
                                        MachineMemOperand::Flags Flags,
                                        unsigned *Fast) const override;
 
    EVT getOptimalMemOpType(LLVMContext &Context, const MemOp &Op,
                            const AttributeList &FuncAttributes) const override;
 
    bool isTruncateFree(Type *SrcTy, Type *DstTy) const override;
    bool isTruncateFree(EVT SrcVT, EVT DstVT) const override;
    bool isZExtFree(SDValue Val, EVT VT2) const override;
    Type* shouldConvertSplatType(ShuffleVectorInst* SVI) const override;
 
    bool isFNegFree(EVT VT) const override;
 
    bool isVectorLoadExtDesirable(SDValue ExtVal) const override;
 
    bool allowTruncateForTailCall(Type *Ty1, Type *Ty2) const override;
 
 
    /// isLegalAddressingMode - Return true if the addressing mode represented
    /// by AM is legal for this target, for a load/store of the specified type.
    bool isLegalAddressingMode(const DataLayout &DL, const AddrMode &AM,
                               Type *Ty, unsigned AS,
                               Instruction *I = nullptr) const override;
 
    bool isLegalT2ScaledAddressingMode(const AddrMode &AM, EVT VT) const;
 
    /// Returns true if the addressing mode representing by AM is legal
    /// for the Thumb1 target, for a load/store of the specified type.
    bool isLegalT1ScaledAddressingMode(const AddrMode &AM, EVT VT) const;
 
    /// isLegalICmpImmediate - Return true if the specified immediate is legal
    /// icmp immediate, that is the target has icmp instructions which can
    /// compare a register against the immediate without having to materialize
    /// the immediate into a register.
    bool isLegalICmpImmediate(int64_t Imm) const override;
 
    /// isLegalAddImmediate - Return true if the specified immediate is legal
    /// add immediate, that is the target has add instructions which can
    /// add a register and the immediate without having to materialize
    /// the immediate into a register.
    bool isLegalAddImmediate(int64_t Imm) const override;
 
    /// getPreIndexedAddressParts - returns true by value, base pointer and
    /// offset pointer and addressing mode by reference if the node's address
    /// can be legally represented as pre-indexed load / store address.
    bool getPreIndexedAddressParts(SDNode *N, SDValue &Base, SDValue &Offset,
                                   ISD::MemIndexedMode &AM,
                                   SelectionDAG &DAG) const override;
 
    /// getPostIndexedAddressParts - returns true by value, base pointer and
    /// offset pointer and addressing mode by reference if this node can be
    /// combined with a load / store to form a post-indexed load / store.
    bool getPostIndexedAddressParts(SDNode *N, SDNode *Op, SDValue &Base,
                                    SDValue &Offset, ISD::MemIndexedMode &AM,
                                    SelectionDAG &DAG) const override;
 
    void computeKnownBitsForTargetNode(const SDValue Op, KnownBits &Known,
                                       const APInt &DemandedElts,
                                       const SelectionDAG &DAG,
                                       unsigned Depth) const override;
 
    bool targetShrinkDemandedConstant(SDValue Op, const APInt &DemandedBits,
                                      const APInt &DemandedElts,
                                      TargetLoweringOpt &TLO) const override;
 
    ConstraintType getConstraintType(StringRef Constraint) const override;
 
    /// Examine constraint string and operand type and determine a weight value.
    /// The operand object must already have been set up with the operand type.
    ConstraintWeight getSingleConstraintMatchWeight(
      AsmOperandInfo &info, const char *constraint) const override;
 
    std::pair<unsigned, const TargetRegisterClass *>
    getRegForInlineAsmConstraint(const TargetRegisterInfo *TRI,
                                 StringRef Constraint, MVT VT) const override;
 
    const char *LowerXConstraint(EVT ConstraintVT) const override;
 
    /// LowerAsmOperandForConstraint - Lower the specified operand into the Ops
    /// vector.  If it is invalid, don't add anything to Ops. If hasMemory is
    /// true it means one of the asm constraint of the inline asm instruction
    /// being processed is 'm'.
    void LowerAsmOperandForConstraint(SDValue Op, StringRef Constraint,
                                      std::vector<SDValue> &Ops,
                                      SelectionDAG &DAG) const override;
 
    InlineAsm::ConstraintCode
    getInlineAsmMemConstraint(StringRef ConstraintCode) const override {
      if (ConstraintCode == "Q")
        return InlineAsm::ConstraintCode::Q;
      if (ConstraintCode.size() == 2) {
        if (ConstraintCode[0] == 'U') {
          switch(ConstraintCode[1]) {
          default:
            break;
          case 'm':
            return InlineAsm::ConstraintCode::Um;
          case 'n':
            return InlineAsm::ConstraintCode::Un;
          case 'q':
            return InlineAsm::ConstraintCode::Uq;
          case 's':
            return InlineAsm::ConstraintCode::Us;
          case 't':
            return InlineAsm::ConstraintCode::Ut;
          case 'v':
            return InlineAsm::ConstraintCode::Uv;
          case 'y':
            return InlineAsm::ConstraintCode::Uy;
          }
        }
      }
      return TargetLowering::getInlineAsmMemConstraint(ConstraintCode);
    }
 
    const ARMSubtarget* getSubtarget() const {
      return Subtarget;
    }
 
    /// getRegClassFor - Return the register class that should be used for the
    /// specified value type.
    const TargetRegisterClass *
    getRegClassFor(MVT VT, bool isDivergent = false) const override;
 
    bool shouldAlignPointerArgs(CallInst *CI, unsigned &MinSize,
                                Align &PrefAlign) const override;
 
    /// createFastISel - This method returns a target specific FastISel object,
    /// or null if the target does not support "fast" ISel.
    FastISel *
    createFastISel(FunctionLoweringInfo &funcInfo,
                   const TargetLibraryInfo *libInfo,
                   const LibcallLoweringInfo *libcallLowering) const override;
 
    Sched::Preference getSchedulingPreference(SDNode *N) const override;
 
    bool preferZeroCompareBranch() const override { return true; }
 
    bool preferSelectsOverBooleanArithmetic(EVT VT) const override;
 
    bool isMaskAndCmp0FoldingBeneficial(const Instruction &AndI) const override;
 
    bool hasAndNotCompare(SDValue V) const override {
      // We can use bics for any scalar.
      return V.getValueType().isScalarInteger();
    }
 
    bool hasAndNot(SDValue Y) const override;
 
    bool
    isShuffleMaskLegal(ArrayRef<int> M, EVT VT) const override;
    bool isOffsetFoldingLegal(const GlobalAddressSDNode *GA) const override;
 
    /// isFPImmLegal - Returns true if the target can instruction select the
    /// specified FP immediate natively. If false, the legalizer will
    /// materialize the FP immediate as a load from a constant pool.
    bool isFPImmLegal(const APFloat &Imm, EVT VT,
                      bool ForCodeSize = false) const override;
 
    void getTgtMemIntrinsic(SmallVectorImpl<IntrinsicInfo> &Infos,
                            const CallBase &I, MachineFunction &MF,
                            unsigned Intrinsic) const override;
 
    /// Returns true if it is beneficial to convert a load of a constant
    /// to just the constant itself.
    bool shouldConvertConstantLoadToIntImm(const APInt &Imm,
                                           Type *Ty) const override;
 
    /// Return true if EXTRACT_SUBVECTOR is cheap for this result type
    /// with this index.
    bool isExtractSubvectorCheap(EVT ResVT, EVT SrcVT,
                                 unsigned Index) const override;
 
    bool shouldFormOverflowOp(unsigned Opcode, EVT VT,
                              bool MathUsed) const override {
      // Using overflow ops for overflow checks only should beneficial on ARM.
      return TargetLowering::shouldFormOverflowOp(Opcode, VT, true);
    }
 
    bool shouldReassociateReduction(unsigned Opc, EVT VT) const override {
      return Opc != ISD::VECREDUCE_ADD;
    }
 
    /// Returns true if an argument of type Ty needs to be passed in a
    /// contiguous block of registers in calling convention CallConv.
    bool functionArgumentNeedsConsecutiveRegisters(
        Type *Ty, CallingConv::ID CallConv, bool isVarArg,
        const DataLayout &DL) const override;
 
    /// If a physical register, this returns the register that receives the
    /// exception address on entry to an EH pad.
    Register
    getExceptionPointerRegister(const Constant *PersonalityFn) const override;
 
    /// If a physical register, this returns the register that receives the
    /// exception typeid on entry to a landing pad.
    Register
    getExceptionSelectorRegister(const Constant *PersonalityFn) const override;
 
    Instruction *makeDMB(IRBuilderBase &Builder, ARM_MB::MemBOpt Domain) const;
    Value *emitLoadLinked(IRBuilderBase &Builder, Type *ValueTy, Value *Addr,
                          AtomicOrdering Ord) const override;
    Value *emitStoreConditional(IRBuilderBase &Builder, Value *Val, Value *Addr,
                                AtomicOrdering Ord) const override;
 
    void
    emitAtomicCmpXchgNoStoreLLBalance(IRBuilderBase &Builder) const override;
 
    Instruction *emitLeadingFence(IRBuilderBase &Builder, Instruction *Inst,
                                  AtomicOrdering Ord) const override;
    Instruction *emitTrailingFence(IRBuilderBase &Builder, Instruction *Inst,
                                   AtomicOrdering Ord) const override;
 
    unsigned getMaxSupportedInterleaveFactor() const override;
 
    bool lowerInterleavedLoad(Instruction *Load, Value *Mask,
                              ArrayRef<ShuffleVectorInst *> Shuffles,
                              ArrayRef<unsigned> Indices, unsigned Factor,
                              const APInt &GapMask) const override;
    bool lowerInterleavedStore(Instruction *Store, Value *Mask,
                               ShuffleVectorInst *SVI, unsigned Factor,
                               const APInt &GapMask) const override;
 
    bool shouldInsertFencesForAtomic(const Instruction *I) const override;
    TargetLoweringBase::AtomicExpansionKind
    shouldExpandAtomicLoadInIR(LoadInst *LI) const override;
    TargetLoweringBase::AtomicExpansionKind
    shouldExpandAtomicStoreInIR(StoreInst *SI) const override;
    TargetLoweringBase::AtomicExpansionKind
    shouldExpandAtomicRMWInIR(const AtomicRMWInst *AI) const override;
    TargetLoweringBase::AtomicExpansionKind
    shouldExpandAtomicCmpXchgInIR(const AtomicCmpXchgInst *AI) const override;
 
    bool useLoadStackGuardNode(const Module &M) const override;
 
    void
    insertSSPDeclarations(Module &M,
                          const LibcallLoweringInfo &Libcalls) const override;
 
    bool canCombineStoreAndExtract(Type *VectorTy, Value *Idx,
                                   unsigned &Cost) const override;
 
    bool canCreateUndefOrPoisonForTargetNode(SDValue Op,
                                             const APInt &DemandedElts,
                                             const SelectionDAG &DAG,
                                             UndefPoisonKind Kind,
                                             bool ConsiderFlags,
                                             unsigned Depth) const override;
 
    bool canMergeStoresTo(unsigned AddressSpace, EVT MemVT,
                          const MachineFunction &MF) const override {
      // Do not merge to larger than i32.
      return (MemVT.getSizeInBits() <= 32);
    }
 
    bool isCheapToSpeculateCttz(Type *Ty) const override;
    bool isCheapToSpeculateCtlz(Type *Ty) const override;
 
    bool convertSetCCLogicToBitwiseLogic(EVT VT) const override {
      return VT.isScalarInteger();
    }
 
    bool supportSwiftError() const override {
      return true;
    }
 
    bool supportSplitCSR(MachineFunction *MF) const override {
      return MF->getFunction().getCallingConv() == CallingConv::CXX_FAST_TLS &&
             MF->getFunction().hasFnAttribute(Attribute::NoUnwind);
    }
 
    bool hasStandaloneRem(EVT VT) const override {
      return HasStandaloneRem;
    }
 
    ShiftLegalizationStrategy
    preferredShiftLegalizationStrategy(SelectionDAG &DAG, SDNode *N,
                                       unsigned ExpansionFactor) const override;
 
    CCAssignFn *CCAssignFnForCall(CallingConv::ID CC, bool isVarArg) const;
    CCAssignFn *CCAssignFnForReturn(CallingConv::ID CC, bool isVarArg) const;
 
    /// Returns true if \p VecTy is a legal interleaved access type. This
    /// function checks the vector element type and the overall width of the
    /// vector.
    bool isLegalInterleavedAccessType(unsigned Factor, FixedVectorType *VecTy,
                                      Align Alignment,
                                      const DataLayout &DL) const;
 
    bool isMulAddWithConstProfitable(SDValue AddNode,
                                     SDValue ConstNode) const override;
 
    bool alignLoopsWithOptSize() const override;
 
    /// Returns the number of interleaved accesses that will be generated when
    /// lowering accesses of the given type.
    unsigned getNumInterleavedAccesses(VectorType *VecTy,
                                       const DataLayout &DL) const;
 
    void finalizeLowering(MachineFunction &MF) const override;
 
    /// Return the correct alignment for the current calling convention.
    Align getABIAlignmentForCallingConv(Type *ArgTy,
                                        const DataLayout &DL) const override;
 
    bool isDesirableToCommuteWithShift(const SDNode *N,
                                       CombineLevel Level) const override;
 
    bool isDesirableToCommuteXorWithShift(const SDNode *N) const override;
 
    bool shouldFoldConstantShiftPairToMask(const SDNode *N) const override;
 
    /// Return true if it is profitable to fold a pair of shifts into a mask.
    bool shouldFoldMaskToVariableShiftPair(SDValue Y) const override {
      EVT VT = Y.getValueType();
 
      if (VT.isVector())
        return false;
 
      return VT.getScalarSizeInBits() <= 32;
    }
 
    bool shouldFoldSelectWithIdentityConstant(unsigned BinOpcode, EVT VT,
                                              unsigned SelectOpcode, SDValue X,
                                              SDValue Y) const override;
 
    bool preferIncOfAddToSubOfNot(EVT VT) const override;
 
    bool shouldConvertFpToSat(unsigned Op, EVT FPVT, EVT VT) const override;
 
    bool isComplexDeinterleavingSupported() const override;
    bool isComplexDeinterleavingOperationSupported(
        ComplexDeinterleavingOperation Operation, Type *Ty) const override;
 
    Value *createComplexDeinterleavingIR(
        IRBuilderBase &B, ComplexDeinterleavingOperation OperationType,
        ComplexDeinterleavingRotation Rotation, Value *InputA, Value *InputB,
        Value *Accumulator = nullptr) const override;
 
    bool useFPRegsForHalfType() const override { return true; }
 
  protected:
    std::pair<const TargetRegisterClass *, uint8_t>
    findRepresentativeClass(const TargetRegisterInfo *TRI,
                            MVT VT) const override;
 
  private:
    /// Subtarget - Keep a pointer to the ARMSubtarget around so that we can
    /// make the right decision when generating code for different targets.
    const ARMSubtarget *Subtarget;
 
    const TargetRegisterInfo *RegInfo;
 
    const InstrItineraryData *Itins;
 
    // TODO: remove this, and have shouldInsertFencesForAtomic do the proper
    // check.
    bool InsertFencesForAtomic;
 
    bool HasStandaloneRem = true;
 
    void addTypeForNEON(MVT VT, MVT PromotedLdStVT);
    void addDRTypeForNEON(MVT VT);
    void addQRTypeForNEON(MVT VT);
    std::pair<SDValue, SDValue> getARMXALUOOp(SDValue Op, SelectionDAG &DAG, SDValue &ARMcc) const;
 
    using RegsToPassVector = SmallVector<std::pair<unsigned, SDValue>, 8>;
 
    void PassF64ArgInRegs(const SDLoc &dl, SelectionDAG &DAG, SDValue Chain,
                          SDValue &Arg, RegsToPassVector &RegsToPass,
                          CCValAssign &VA, CCValAssign &NextVA,
                          SDValue &StackPtr,
                          SmallVectorImpl<SDValue> &MemOpChains,
                          bool IsTailCall,
                          int SPDiff) const;
    SDValue GetF64FormalArgument(CCValAssign &VA, CCValAssign &NextVA,
                                 SDValue &Root, SelectionDAG &DAG,
                                 const SDLoc &dl) const;
 
    CallingConv::ID getEffectiveCallingConv(CallingConv::ID CC,
                                            bool isVarArg) const;
    CCAssignFn *CCAssignFnForNode(CallingConv::ID CC, bool Return,
                                  bool isVarArg) const;
    std::pair<SDValue, MachinePointerInfo>
    computeAddrForCallArg(const SDLoc &dl, SelectionDAG &DAG,
                          const CCValAssign &VA, SDValue StackPtr,
                          bool IsTailCall, int SPDiff) const;
    ByValCopyKind ByValNeedsCopyForTailCall(SelectionDAG &DAG, SDValue Src,
                                            SDValue Dst,
                                            ISD::ArgFlagsTy Flags) const;
    SDValue LowerEH_SJLJ_SETJMP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerEH_SJLJ_LONGJMP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerEH_SJLJ_SETUP_DISPATCH(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINTRINSIC_VOID(SDValue Op, SelectionDAG &DAG,
                                    const ARMSubtarget *Subtarget) const;
    SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG,
                                    const ARMSubtarget *Subtarget) const;
    SDValue LowerBlockAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalAddressELF(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalAddressWindows(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalTLSAddress(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerToTLSGeneralDynamicModel(GlobalAddressSDNode *GA,
                                            SelectionDAG &DAG) const;
    SDValue LowerToTLSExecModels(GlobalAddressSDNode *GA,
                                 SelectionDAG &DAG,
                                 TLSModel::Model model) const;
    SDValue LowerGlobalTLSAddressDarwin(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGlobalTLSAddressWindows(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerALUO(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSELECT(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSELECT_CC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBRCOND(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerBR_CC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFCOPYSIGN(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerRETURNADDR(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFRAMEADDR(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerShiftRightParts(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerShiftLeftParts(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerGET_ROUNDING(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSET_ROUNDING(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSET_FPMODE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerRESET_FPMODE(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerConstantFP(SDValue Op, SelectionDAG &DAG,
                            const ARMSubtarget *ST) const;
    SDValue LowerBUILD_VECTOR(SDValue Op, SelectionDAG &DAG,
                              const ARMSubtarget *ST) const;
    SDValue LowerINSERT_VECTOR_ELT(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerDivRem(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerDIV_Windows(SDValue Op, SelectionDAG &DAG, bool Signed) const;
    void ExpandDIV_Windows(SDValue Op, SelectionDAG &DAG, bool Signed,
                           SmallVectorImpl<SDValue> &Results) const;
    SDValue ExpandBITCAST(SDNode *N, SelectionDAG &DAG,
                          const ARMSubtarget *Subtarget) const;
    SDValue LowerWindowsDIVLibCall(SDValue Op, SelectionDAG &DAG, bool Signed,
                                   SDValue &Chain) const;
    SDValue LowerREM(SDNode *N, SelectionDAG &DAG) const;
    SDValue LowerDYNAMIC_STACKALLOC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_ROUND(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_EXTEND(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_TO_INT(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerINT_TO_FP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFSETCC(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerSPONENTRY(SDValue Op, SelectionDAG &DAG) const;
    void LowerLOAD(SDNode *N, SmallVectorImpl<SDValue> &Results,
                   SelectionDAG &DAG) const;
    SDValue LowerSTORE(SDValue Op, SelectionDAG &DAG,
                       const ARMSubtarget *Subtarget) const;
    std::pair<SDValue, SDValue>
    LowerAEABIUnalignedLoad(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerAEABIUnalignedStore(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerFP_TO_BF16(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerCMP(SDValue Op, SelectionDAG &DAG) const;
    SDValue LowerABS(SDValue Op, SelectionDAG &DAG) const;
    Register getRegisterByName(const char* RegName, LLT VT,
                               const MachineFunction &MF) const override;
 
    SDValue BuildSDIVPow2(SDNode *N, const APInt &Divisor, SelectionDAG &DAG,
                          SmallVectorImpl<SDNode *> &Created) const override;
 
    bool isFMAFasterThanFMulAndFAdd(const MachineFunction &MF,
                                    EVT VT) const override;
 
    SDValue MoveToHPR(const SDLoc &dl, SelectionDAG &DAG, MVT LocVT, MVT ValVT,
                      SDValue Val) const;
    SDValue MoveFromHPR(const SDLoc &dl, SelectionDAG &DAG, MVT LocVT,
                        MVT ValVT, SDValue Val) const;
 
    SDValue ReconstructShuffle(SDValue Op, SelectionDAG &DAG) const;
 
    SDValue LowerCallResult(SDValue Chain, SDValue InGlue,
                            CallingConv::ID CallConv, bool isVarArg,
                            const SmallVectorImpl<ISD::InputArg> &Ins,
                            const SDLoc &dl, SelectionDAG &DAG,
                            SmallVectorImpl<SDValue> &InVals, bool isThisReturn,
                            SDValue ThisVal, bool isCmseNSCall) const;
 
    void initializeSplitCSR(MachineBasicBlock *Entry) const override;
    void insertCopiesSplitCSR(
      MachineBasicBlock *Entry,
      const SmallVectorImpl<MachineBasicBlock *> &Exits) const override;
 
    bool splitValueIntoRegisterParts(
        SelectionDAG & DAG, const SDLoc &DL, SDValue Val, SDValue *Parts,
        unsigned NumParts, MVT PartVT, std::optional<CallingConv::ID> CC)
        const override;
 
    SDValue joinRegisterPartsIntoValue(
        SelectionDAG & DAG, const SDLoc &DL, const SDValue *Parts,
        unsigned NumParts, MVT PartVT, EVT ValueVT,
        std::optional<CallingConv::ID> CC) const override;
 
    SDValue
    LowerFormalArguments(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
                         const SmallVectorImpl<ISD::InputArg> &Ins,
                         const SDLoc &dl, SelectionDAG &DAG,
                         SmallVectorImpl<SDValue> &InVals) const override;
 
    int StoreByValRegs(CCState &CCInfo, SelectionDAG &DAG, const SDLoc &dl,
                       SDValue &Chain, const Value *OrigArg,
                       unsigned InRegsParamRecordIdx, int ArgOffset,
                       unsigned ArgSize) const;
 
    void VarArgStyleRegisters(CCState &CCInfo, SelectionDAG &DAG,
                              const SDLoc &dl, SDValue &Chain,
                              unsigned ArgOffset, unsigned TotalArgRegsSaveSize,
                              bool ForceMutable = false) const;
 
    SDValue LowerCall(TargetLowering::CallLoweringInfo &CLI,
                      SmallVectorImpl<SDValue> &InVals) const override;
 
    /// HandleByVal - Target-specific cleanup for ByVal support.
    void HandleByVal(CCState *, unsigned &, Align) const override;
 
    /// IsEligibleForTailCallOptimization - Check whether the call is eligible
    /// for tail call optimization. Targets which want to do tail call
    /// optimization should implement this function.
    bool IsEligibleForTailCallOptimization(
        TargetLowering::CallLoweringInfo &CLI, CCState &CCInfo,
        SmallVectorImpl<CCValAssign> &ArgLocs, const bool isIndirect) const;
 
    bool CanLowerReturn(CallingConv::ID CallConv,
                        MachineFunction &MF, bool isVarArg,
                        const SmallVectorImpl<ISD::OutputArg> &Outs,
                        LLVMContext &Context, const Type *RetTy) const override;
 
    SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv, bool isVarArg,
                        const SmallVectorImpl<ISD::OutputArg> &Outs,
                        const SmallVectorImpl<SDValue> &OutVals,
                        const SDLoc &dl, SelectionDAG &DAG) const override;
 
    bool isUsedByReturnOnly(SDNode *N, SDValue &Chain) const override;
 
    bool mayBeEmittedAsTailCall(const CallInst *CI) const override;
 
    bool shouldConsiderGEPOffsetSplit() const override { return true; }
 
    bool isUnsupportedFloatingType(EVT VT) const;
 
    ArrayRef<MCPhysReg> getRoundingControlRegisters() const override;
 
    SDValue getCMOV(const SDLoc &dl, EVT VT, SDValue FalseVal, SDValue TrueVal,
                    SDValue ARMcc, SDValue Flags, SelectionDAG &DAG) const;
    SDValue getARMCmp(SDValue LHS, SDValue RHS, ISD::CondCode CC,
                      SDValue &ARMcc, SelectionDAG &DAG, const SDLoc &dl) const;
    SDValue getVFPCmp(SDValue LHS, SDValue RHS, SelectionDAG &DAG,
                      const SDLoc &dl, bool Signaling = false) const;
 
    SDValue OptimizeVFPBrcond(SDValue Op, SelectionDAG &DAG) const;
 
    void SetupEntryBlockForSjLj(MachineInstr &MI, MachineBasicBlock *MBB,
                                MachineBasicBlock *DispatchBB, int FI) const;
 
    void EmitSjLjDispatchBlock(MachineInstr &MI, MachineBasicBlock *MBB) const;
 
    MachineBasicBlock *EmitStructByval(MachineInstr &MI,
                                       MachineBasicBlock *MBB) const;
 
    MachineBasicBlock *EmitLowered__chkstk(MachineInstr &MI,
                                           MachineBasicBlock *MBB) const;
    MachineBasicBlock *EmitLowered__dbzchk(MachineInstr &MI,
                                           MachineBasicBlock *MBB) const;
    void addMVEVectorTypes(bool HasMVEFP);
    void addAllExtLoads(const MVT From, const MVT To, LegalizeAction Action);
    void setAllExpand(MVT VT);
  };
 
  enum VMOVModImmType {
    VMOVModImm,
    VMVNModImm,
    MVEVMVNModImm,
    OtherModImm
  };
 
  namespace ARM {
 
  FastISel *createFastISel(FunctionLoweringInfo &funcInfo,
                           const TargetLibraryInfo *libInfo,
                           const LibcallLoweringInfo *libcallLowering);
 
  } // end namespace ARM
 
} // end namespace llvm
 
#endif // LLVM_LIB_TARGET_ARM_ARMISELLOWERING_H