//===-- ARM6464FastISel.cpp - ARM64 FastISel implementation ---------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines the ARM64-specific support for the FastISel class. Some
// of the target-specific code is generated by tablegen in the file
// ARM64GenFastISel.inc, which is #included here.
//
//===----------------------------------------------------------------------===//

#include "ARM64.h"
#include "ARM64TargetMachine.h"
#include "ARM64Subtarget.h"
#include "ARM64CallingConv.h"
#include "MCTargetDesc/ARM64AddressingModes.h"
#include "llvm/CodeGen/CallingConvLower.h"
#include "llvm/CodeGen/FastISel.h"
#include "llvm/CodeGen/FunctionLoweringInfo.h"
#include "llvm/CodeGen/MachineConstantPool.h"
#include "llvm/CodeGen/MachineFrameInfo.h"
#include "llvm/CodeGen/MachineInstrBuilder.h"
#include "llvm/CodeGen/MachineRegisterInfo.h"
#include "llvm/IR/CallingConv.h"
#include "llvm/IR/DataLayout.h"
#include "llvm/IR/DerivedTypes.h"
#include "llvm/IR/Function.h"
#include "llvm/IR/GetElementPtrTypeIterator.h"
#include "llvm/IR/GlobalAlias.h"
#include "llvm/IR/GlobalVariable.h"
#include "llvm/IR/Instructions.h"
#include "llvm/IR/IntrinsicInst.h"
#include "llvm/IR/Operator.h"
#include "llvm/Support/CommandLine.h"
using namespace llvm;

namespace {

class ARM64FastISel : public FastISel {

  class Address {
  public:
    typedef enum {
      RegBase,
      FrameIndexBase
    } BaseKind;

  private:
    BaseKind Kind;
    union {
      unsigned Reg;
      int FI;
    } Base;
    int64_t Offset;

  public:
    Address() : Kind(RegBase), Offset(0) { Base.Reg = 0; }
    void setKind(BaseKind K) { Kind = K; }
    BaseKind getKind() const { return Kind; }
    bool isRegBase() const { return Kind == RegBase; }
    bool isFIBase() const { return Kind == FrameIndexBase; }
    void setReg(unsigned Reg) {
      assert(isRegBase() && "Invalid base register access!");
      Base.Reg = Reg;
    }
    unsigned getReg() const {
      assert(isRegBase() && "Invalid base register access!");
      return Base.Reg;
    }
    void setFI(unsigned FI) {
      assert(isFIBase() && "Invalid base frame index  access!");
      Base.FI = FI;
    }
    unsigned getFI() const {
      assert(isFIBase() && "Invalid base frame index access!");
      return Base.FI;
    }
    void setOffset(int64_t O) { Offset = O; }
    int64_t getOffset() { return Offset; }

    bool isValid() { return isFIBase() || (isRegBase() && getReg() != 0); }
  };

  /// Subtarget - Keep a pointer to the ARM64Subtarget around so that we can
  /// make the right decision when generating code for different targets.
  const ARM64Subtarget *Subtarget;
  LLVMContext *Context;

private:
  // Selection routines.
  bool SelectLoad(const Instruction *I);
  bool SelectStore(const Instruction *I);
  bool SelectBranch(const Instruction *I);
  bool SelectIndirectBr(const Instruction *I);
  bool SelectCmp(const Instruction *I);
  bool SelectSelect(const Instruction *I);
  bool SelectFPExt(const Instruction *I);
  bool SelectFPTrunc(const Instruction *I);
  bool SelectFPToInt(const Instruction *I, bool Signed);
  bool SelectIntToFP(const Instruction *I, bool Signed);
  bool SelectRem(const Instruction *I, unsigned ISDOpcode);
  bool SelectCall(const Instruction *I, const char *IntrMemName);
  bool SelectIntrinsicCall(const IntrinsicInst &I);
  bool SelectRet(const Instruction *I);
  bool SelectTrunc(const Instruction *I);
  bool SelectIntExt(const Instruction *I);
  bool SelectMul(const Instruction *I);

  // Utility helper routines.
  bool isTypeLegal(Type *Ty, MVT &VT);
  bool isLoadStoreTypeLegal(Type *Ty, MVT &VT);
  bool ComputeAddress(const Value *Obj, Address &Addr);
  bool SimplifyAddress(Address &Addr, MVT VT, int64_t ScaleFactor,
                       bool UseUnscaled);
  void AddLoadStoreOperands(Address &Addr, const MachineInstrBuilder &MIB,
                            unsigned Flags, bool UseUnscaled);
  bool IsMemCpySmall(uint64_t Len, unsigned Alignment);
  bool TryEmitSmallMemCpy(Address Dest, Address Src, uint64_t Len,
                          unsigned Alignment);
  // Emit functions.
  bool EmitCmp(Value *Src1Value, Value *Src2Value, bool isZExt);
  bool EmitLoad(MVT VT, unsigned &ResultReg, Address Addr,
                bool UseUnscaled = false);
  bool EmitStore(MVT VT, unsigned SrcReg, Address Addr,
                 bool UseUnscaled = false);
  unsigned EmitIntExt(MVT SrcVT, unsigned SrcReg, MVT DestVT, bool isZExt);
  unsigned Emiti1Ext(unsigned SrcReg, MVT DestVT, bool isZExt);

  unsigned ARM64MaterializeFP(const ConstantFP *CFP, MVT VT);
  unsigned ARM64MaterializeGV(const GlobalValue *GV);

  // Call handling routines.
private:
  CCAssignFn *CCAssignFnForCall(CallingConv::ID CC) const;
  bool ProcessCallArgs(SmallVectorImpl<Value *> &Args,
                       SmallVectorImpl<unsigned> &ArgRegs,
                       SmallVectorImpl<MVT> &ArgVTs,
                       SmallVectorImpl<ISD::ArgFlagsTy> &ArgFlags,
                       SmallVectorImpl<unsigned> &RegArgs, CallingConv::ID CC,
                       unsigned &NumBytes);
  bool FinishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
                  const Instruction *I, CallingConv::ID CC, unsigned &NumBytes);

public:
  // Backend specific FastISel code.
  unsigned TargetMaterializeAlloca(const AllocaInst *AI) override;
  unsigned TargetMaterializeConstant(const Constant *C) override;

  explicit ARM64FastISel(FunctionLoweringInfo &funcInfo,
                         const TargetLibraryInfo *libInfo)
      : FastISel(funcInfo, libInfo) {
    Subtarget = &TM.getSubtarget<ARM64Subtarget>();
    Context = &funcInfo.Fn->getContext();
  }

  bool TargetSelectInstruction(const Instruction *I) override;

#include "ARM64GenFastISel.inc"
};

} // end anonymous namespace

#include "ARM64GenCallingConv.inc"

CCAssignFn *ARM64FastISel::CCAssignFnForCall(CallingConv::ID CC) const {
  if (CC == CallingConv::WebKit_JS)
    return CC_ARM64_WebKit_JS;
  return Subtarget->isTargetDarwin() ? CC_ARM64_DarwinPCS : CC_ARM64_AAPCS;
}

unsigned ARM64FastISel::TargetMaterializeAlloca(const AllocaInst *AI) {
  assert(TLI.getValueType(AI->getType(), true) == MVT::i64 &&
         "Alloca should always return a pointer.");

  // Don't handle dynamic allocas.
  if (!FuncInfo.StaticAllocaMap.count(AI))
    return 0;

  DenseMap<const AllocaInst *, int>::iterator SI =
      FuncInfo.StaticAllocaMap.find(AI);

  if (SI != FuncInfo.StaticAllocaMap.end()) {
    unsigned ResultReg = createResultReg(&ARM64::GPR64RegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ADDXri),
            ResultReg)
        .addFrameIndex(SI->second)
        .addImm(0)
        .addImm(0);
    return ResultReg;
  }

  return 0;
}

unsigned ARM64FastISel::ARM64MaterializeFP(const ConstantFP *CFP, MVT VT) {
  if (VT != MVT::f32 && VT != MVT::f64)
    return 0;

  const APFloat Val = CFP->getValueAPF();
  bool is64bit = (VT == MVT::f64);

  // This checks to see if we can use FMOV instructions to materialize
  // a constant, otherwise we have to materialize via the constant pool.
  if (TLI.isFPImmLegal(Val, VT)) {
    int Imm;
    unsigned Opc;
    if (is64bit) {
      Imm = ARM64_AM::getFP64Imm(Val);
      Opc = ARM64::FMOVDi;
    } else {
      Imm = ARM64_AM::getFP32Imm(Val);
      Opc = ARM64::FMOVSi;
    }
    unsigned ResultReg = createResultReg(TLI.getRegClassFor(VT));
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
        .addImm(Imm);
    return ResultReg;
  }

  // Materialize via constant pool.  MachineConstantPool wants an explicit
  // alignment.
  unsigned Align = DL.getPrefTypeAlignment(CFP->getType());
  if (Align == 0)
    Align = DL.getTypeAllocSize(CFP->getType());

  unsigned Idx = MCP.getConstantPoolIndex(cast<Constant>(CFP), Align);
  unsigned ADRPReg = createResultReg(&ARM64::GPR64commonRegClass);
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ADRP),
          ADRPReg).addConstantPoolIndex(Idx, 0, ARM64II::MO_PAGE);

  unsigned Opc = is64bit ? ARM64::LDRDui : ARM64::LDRSui;
  unsigned ResultReg = createResultReg(TLI.getRegClassFor(VT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
      .addReg(ADRPReg)
      .addConstantPoolIndex(Idx, 0, ARM64II::MO_PAGEOFF | ARM64II::MO_NC);
  return ResultReg;
}

unsigned ARM64FastISel::ARM64MaterializeGV(const GlobalValue *GV) {
  // We can't handle thread-local variables quickly yet. Unfortunately we have
  // to peer through any aliases to find out if that rule applies.
  const GlobalValue *TLSGV = GV;
  if (const GlobalAlias *GA = dyn_cast<GlobalAlias>(GV))
    TLSGV = GA->getAliasedGlobal();

  if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(TLSGV))
    if (GVar->isThreadLocal())
      return 0;

  unsigned char OpFlags = Subtarget->ClassifyGlobalReference(GV, TM);

  EVT DestEVT = TLI.getValueType(GV->getType(), true);
  if (!DestEVT.isSimple())
    return 0;

  unsigned ADRPReg = createResultReg(&ARM64::GPR64commonRegClass);
  unsigned ResultReg;

  if (OpFlags & ARM64II::MO_GOT) {
    // ADRP + LDRX
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ADRP),
            ADRPReg)
        .addGlobalAddress(GV, 0, ARM64II::MO_GOT | ARM64II::MO_PAGE);

    ResultReg = createResultReg(&ARM64::GPR64RegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::LDRXui),
            ResultReg)
        .addReg(ADRPReg)
        .addGlobalAddress(GV, 0, ARM64II::MO_GOT | ARM64II::MO_PAGEOFF |
                          ARM64II::MO_NC);
  } else {
    // ADRP + ADDX
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ADRP),
            ADRPReg).addGlobalAddress(GV, 0, ARM64II::MO_PAGE);

    ResultReg = createResultReg(&ARM64::GPR64spRegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ADDXri),
            ResultReg)
        .addReg(ADRPReg)
        .addGlobalAddress(GV, 0, ARM64II::MO_PAGEOFF | ARM64II::MO_NC)
        .addImm(0);
  }
  return ResultReg;
}

unsigned ARM64FastISel::TargetMaterializeConstant(const Constant *C) {
  EVT CEVT = TLI.getValueType(C->getType(), true);

  // Only handle simple types.
  if (!CEVT.isSimple())
    return 0;
  MVT VT = CEVT.getSimpleVT();

  // FIXME: Handle ConstantInt.
  if (const ConstantFP *CFP = dyn_cast<ConstantFP>(C))
    return ARM64MaterializeFP(CFP, VT);
  else if (const GlobalValue *GV = dyn_cast<GlobalValue>(C))
    return ARM64MaterializeGV(GV);

  return 0;
}

// Computes the address to get to an object.
bool ARM64FastISel::ComputeAddress(const Value *Obj, Address &Addr) {
  const User *U = nullptr;
  unsigned Opcode = Instruction::UserOp1;
  if (const Instruction *I = dyn_cast<Instruction>(Obj)) {
    // Don't walk into other basic blocks unless the object is an alloca from
    // another block, otherwise it may not have a virtual register assigned.
    if (FuncInfo.StaticAllocaMap.count(static_cast<const AllocaInst *>(Obj)) ||
        FuncInfo.MBBMap[I->getParent()] == FuncInfo.MBB) {
      Opcode = I->getOpcode();
      U = I;
    }
  } else if (const ConstantExpr *C = dyn_cast<ConstantExpr>(Obj)) {
    Opcode = C->getOpcode();
    U = C;
  }

  if (const PointerType *Ty = dyn_cast<PointerType>(Obj->getType()))
    if (Ty->getAddressSpace() > 255)
      // Fast instruction selection doesn't support the special
      // address spaces.
      return false;

  switch (Opcode) {
  default:
    break;
  case Instruction::BitCast: {
    // Look through bitcasts.
    return ComputeAddress(U->getOperand(0), Addr);
  }
  case Instruction::IntToPtr: {
    // Look past no-op inttoptrs.
    if (TLI.getValueType(U->getOperand(0)->getType()) == TLI.getPointerTy())
      return ComputeAddress(U->getOperand(0), Addr);
    break;
  }
  case Instruction::PtrToInt: {
    // Look past no-op ptrtoints.
    if (TLI.getValueType(U->getType()) == TLI.getPointerTy())
      return ComputeAddress(U->getOperand(0), Addr);
    break;
  }
  case Instruction::GetElementPtr: {
    Address SavedAddr = Addr;
    uint64_t TmpOffset = Addr.getOffset();

    // Iterate through the GEP folding the constants into offsets where
    // we can.
    gep_type_iterator GTI = gep_type_begin(U);
    for (User::const_op_iterator i = U->op_begin() + 1, e = U->op_end(); i != e;
         ++i, ++GTI) {
      const Value *Op = *i;
      if (StructType *STy = dyn_cast<StructType>(*GTI)) {
        const StructLayout *SL = DL.getStructLayout(STy);
        unsigned Idx = cast<ConstantInt>(Op)->getZExtValue();
        TmpOffset += SL->getElementOffset(Idx);
      } else {
        uint64_t S = DL.getTypeAllocSize(GTI.getIndexedType());
        for (;;) {
          if (const ConstantInt *CI = dyn_cast<ConstantInt>(Op)) {
            // Constant-offset addressing.
            TmpOffset += CI->getSExtValue() * S;
            break;
          }
          if (canFoldAddIntoGEP(U, Op)) {
            // A compatible add with a constant operand. Fold the constant.
            ConstantInt *CI =
                cast<ConstantInt>(cast<AddOperator>(Op)->getOperand(1));
            TmpOffset += CI->getSExtValue() * S;
            // Iterate on the other operand.
            Op = cast<AddOperator>(Op)->getOperand(0);
            continue;
          }
          // Unsupported
          goto unsupported_gep;
        }
      }
    }

    // Try to grab the base operand now.
    Addr.setOffset(TmpOffset);
    if (ComputeAddress(U->getOperand(0), Addr))
      return true;

    // We failed, restore everything and try the other options.
    Addr = SavedAddr;

  unsupported_gep:
    break;
  }
  case Instruction::Alloca: {
    const AllocaInst *AI = cast<AllocaInst>(Obj);
    DenseMap<const AllocaInst *, int>::iterator SI =
        FuncInfo.StaticAllocaMap.find(AI);
    if (SI != FuncInfo.StaticAllocaMap.end()) {
      Addr.setKind(Address::FrameIndexBase);
      Addr.setFI(SI->second);
      return true;
    }
    break;
  }
  }

  // Try to get this in a register if nothing else has worked.
  if (!Addr.isValid())
    Addr.setReg(getRegForValue(Obj));
  return Addr.isValid();
}

bool ARM64FastISel::isTypeLegal(Type *Ty, MVT &VT) {
  EVT evt = TLI.getValueType(Ty, true);

  // Only handle simple types.
  if (evt == MVT::Other || !evt.isSimple())
    return false;
  VT = evt.getSimpleVT();

  // This is a legal type, but it's not something we handle in fast-isel.
  if (VT == MVT::f128)
    return false;

  // Handle all other legal types, i.e. a register that will directly hold this
  // value.
  return TLI.isTypeLegal(VT);
}

bool ARM64FastISel::isLoadStoreTypeLegal(Type *Ty, MVT &VT) {
  if (isTypeLegal(Ty, VT))
    return true;

  // If this is a type than can be sign or zero-extended to a basic operation
  // go ahead and accept it now. For stores, this reflects truncation.
  if (VT == MVT::i1 || VT == MVT::i8 || VT == MVT::i16)
    return true;

  return false;
}

bool ARM64FastISel::SimplifyAddress(Address &Addr, MVT VT, int64_t ScaleFactor,
                                    bool UseUnscaled) {
  bool needsLowering = false;
  int64_t Offset = Addr.getOffset();
  switch (VT.SimpleTy) {
  default:
    return false;
  case MVT::i1:
  case MVT::i8:
  case MVT::i16:
  case MVT::i32:
  case MVT::i64:
  case MVT::f32:
  case MVT::f64:
    if (!UseUnscaled)
      // Using scaled, 12-bit, unsigned immediate offsets.
      needsLowering = ((Offset & 0xfff) != Offset);
    else
      // Using unscaled, 9-bit, signed immediate offsets.
      needsLowering = (Offset > 256 || Offset < -256);
    break;
  }

  // FIXME: If this is a stack pointer and the offset needs to be simplified
  // then put the alloca address into a register, set the base type back to
  // register and continue. This should almost never happen.
  if (needsLowering && Addr.getKind() == Address::FrameIndexBase) {
    return false;
  }

  // Since the offset is too large for the load/store instruction get the
  // reg+offset into a register.
  if (needsLowering) {
    uint64_t UnscaledOffset = Addr.getOffset() * ScaleFactor;
    unsigned ResultReg = FastEmit_ri_(MVT::i64, ISD::ADD, Addr.getReg(), false,
                                      UnscaledOffset, MVT::i64);
    if (ResultReg == 0)
      return false;
    Addr.setReg(ResultReg);
    Addr.setOffset(0);
  }
  return true;
}

void ARM64FastISel::AddLoadStoreOperands(Address &Addr,
                                         const MachineInstrBuilder &MIB,
                                         unsigned Flags, bool UseUnscaled) {
  int64_t Offset = Addr.getOffset();
  // Frame base works a bit differently. Handle it separately.
  if (Addr.getKind() == Address::FrameIndexBase) {
    int FI = Addr.getFI();
    // FIXME: We shouldn't be using getObjectSize/getObjectAlignment.  The size
    // and alignment should be based on the VT.
    MachineMemOperand *MMO = FuncInfo.MF->getMachineMemOperand(
        MachinePointerInfo::getFixedStack(FI, Offset), Flags,
        MFI.getObjectSize(FI), MFI.getObjectAlignment(FI));
    // Now add the rest of the operands.
    MIB.addFrameIndex(FI).addImm(Offset).addMemOperand(MMO);
  } else {
    // Now add the rest of the operands.
    MIB.addReg(Addr.getReg());
    MIB.addImm(Offset);
  }
}

bool ARM64FastISel::EmitLoad(MVT VT, unsigned &ResultReg, Address Addr,
                             bool UseUnscaled) {
  // Negative offsets require unscaled, 9-bit, signed immediate offsets.
  // Otherwise, we try using scaled, 12-bit, unsigned immediate offsets.
  if (!UseUnscaled && Addr.getOffset() < 0)
    UseUnscaled = true;

  unsigned Opc;
  const TargetRegisterClass *RC;
  bool VTIsi1 = false;
  int64_t ScaleFactor = 0;
  switch (VT.SimpleTy) {
  default:
    return false;
  case MVT::i1:
    VTIsi1 = true;
  // Intentional fall-through.
  case MVT::i8:
    Opc = UseUnscaled ? ARM64::LDURBBi : ARM64::LDRBBui;
    RC = &ARM64::GPR32RegClass;
    ScaleFactor = 1;
    break;
  case MVT::i16:
    Opc = UseUnscaled ? ARM64::LDURHHi : ARM64::LDRHHui;
    RC = &ARM64::GPR32RegClass;
    ScaleFactor = 2;
    break;
  case MVT::i32:
    Opc = UseUnscaled ? ARM64::LDURWi : ARM64::LDRWui;
    RC = &ARM64::GPR32RegClass;
    ScaleFactor = 4;
    break;
  case MVT::i64:
    Opc = UseUnscaled ? ARM64::LDURXi : ARM64::LDRXui;
    RC = &ARM64::GPR64RegClass;
    ScaleFactor = 8;
    break;
  case MVT::f32:
    Opc = UseUnscaled ? ARM64::LDURSi : ARM64::LDRSui;
    RC = TLI.getRegClassFor(VT);
    ScaleFactor = 4;
    break;
  case MVT::f64:
    Opc = UseUnscaled ? ARM64::LDURDi : ARM64::LDRDui;
    RC = TLI.getRegClassFor(VT);
    ScaleFactor = 8;
    break;
  }
  // Scale the offset.
  if (!UseUnscaled) {
    int64_t Offset = Addr.getOffset();
    if (Offset & (ScaleFactor - 1))
      // Retry using an unscaled, 9-bit, signed immediate offset.
      return EmitLoad(VT, ResultReg, Addr, /*UseUnscaled*/ true);

    Addr.setOffset(Offset / ScaleFactor);
  }

  // Simplify this down to something we can handle.
  if (!SimplifyAddress(Addr, VT, UseUnscaled ? 1 : ScaleFactor, UseUnscaled))
    return false;

  // Create the base instruction, then add the operands.
  ResultReg = createResultReg(RC);
  MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
                                    TII.get(Opc), ResultReg);
  AddLoadStoreOperands(Addr, MIB, MachineMemOperand::MOLoad, UseUnscaled);

  // Loading an i1 requires special handling.
  if (VTIsi1) {
    MRI.constrainRegClass(ResultReg, &ARM64::GPR32RegClass);
    unsigned ANDReg = createResultReg(&ARM64::GPR32spRegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ANDWri),
            ANDReg)
        .addReg(ResultReg)
        .addImm(ARM64_AM::encodeLogicalImmediate(1, 32));
    ResultReg = ANDReg;
  }
  return true;
}

bool ARM64FastISel::SelectLoad(const Instruction *I) {
  MVT VT;
  // Verify we have a legal type before going any further.  Currently, we handle
  // simple types that will directly fit in a register (i32/f32/i64/f64) or
  // those that can be sign or zero-extended to a basic operation (i1/i8/i16).
  if (!isLoadStoreTypeLegal(I->getType(), VT) || cast<LoadInst>(I)->isAtomic())
    return false;

  // See if we can handle this address.
  Address Addr;
  if (!ComputeAddress(I->getOperand(0), Addr))
    return false;

  unsigned ResultReg;
  if (!EmitLoad(VT, ResultReg, Addr))
    return false;

  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::EmitStore(MVT VT, unsigned SrcReg, Address Addr,
                              bool UseUnscaled) {
  // Negative offsets require unscaled, 9-bit, signed immediate offsets.
  // Otherwise, we try using scaled, 12-bit, unsigned immediate offsets.
  if (!UseUnscaled && Addr.getOffset() < 0)
    UseUnscaled = true;

  unsigned StrOpc;
  bool VTIsi1 = false;
  int64_t ScaleFactor = 0;
  // Using scaled, 12-bit, unsigned immediate offsets.
  switch (VT.SimpleTy) {
  default:
    return false;
  case MVT::i1:
    VTIsi1 = true;
  case MVT::i8:
    StrOpc = UseUnscaled ? ARM64::STURBBi : ARM64::STRBBui;
    ScaleFactor = 1;
    break;
  case MVT::i16:
    StrOpc = UseUnscaled ? ARM64::STURHHi : ARM64::STRHHui;
    ScaleFactor = 2;
    break;
  case MVT::i32:
    StrOpc = UseUnscaled ? ARM64::STURWi : ARM64::STRWui;
    ScaleFactor = 4;
    break;
  case MVT::i64:
    StrOpc = UseUnscaled ? ARM64::STURXi : ARM64::STRXui;
    ScaleFactor = 8;
    break;
  case MVT::f32:
    StrOpc = UseUnscaled ? ARM64::STURSi : ARM64::STRSui;
    ScaleFactor = 4;
    break;
  case MVT::f64:
    StrOpc = UseUnscaled ? ARM64::STURDi : ARM64::STRDui;
    ScaleFactor = 8;
    break;
  }
  // Scale the offset.
  if (!UseUnscaled) {
    int64_t Offset = Addr.getOffset();
    if (Offset & (ScaleFactor - 1))
      // Retry using an unscaled, 9-bit, signed immediate offset.
      return EmitStore(VT, SrcReg, Addr, /*UseUnscaled*/ true);

    Addr.setOffset(Offset / ScaleFactor);
  }

  // Simplify this down to something we can handle.
  if (!SimplifyAddress(Addr, VT, UseUnscaled ? 1 : ScaleFactor, UseUnscaled))
    return false;

  // Storing an i1 requires special handling.
  if (VTIsi1) {
    MRI.constrainRegClass(SrcReg, &ARM64::GPR32RegClass);
    unsigned ANDReg = createResultReg(&ARM64::GPR32spRegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ANDWri),
            ANDReg)
        .addReg(SrcReg)
        .addImm(ARM64_AM::encodeLogicalImmediate(1, 32));
    SrcReg = ANDReg;
  }
  // Create the base instruction, then add the operands.
  MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
                                    TII.get(StrOpc)).addReg(SrcReg);
  AddLoadStoreOperands(Addr, MIB, MachineMemOperand::MOStore, UseUnscaled);
  return true;
}

bool ARM64FastISel::SelectStore(const Instruction *I) {
  MVT VT;
  Value *Op0 = I->getOperand(0);
  // Verify we have a legal type before going any further.  Currently, we handle
  // simple types that will directly fit in a register (i32/f32/i64/f64) or
  // those that can be sign or zero-extended to a basic operation (i1/i8/i16).
  if (!isLoadStoreTypeLegal(Op0->getType(), VT) ||
      cast<StoreInst>(I)->isAtomic())
    return false;

  // Get the value to be stored into a register.
  unsigned SrcReg = getRegForValue(Op0);
  if (SrcReg == 0)
    return false;

  // See if we can handle this address.
  Address Addr;
  if (!ComputeAddress(I->getOperand(1), Addr))
    return false;

  if (!EmitStore(VT, SrcReg, Addr))
    return false;
  return true;
}

static ARM64CC::CondCode getCompareCC(CmpInst::Predicate Pred) {
  switch (Pred) {
  case CmpInst::FCMP_ONE:
  case CmpInst::FCMP_UEQ:
  default:
    // AL is our "false" for now. The other two need more compares.
    return ARM64CC::AL;
  case CmpInst::ICMP_EQ:
  case CmpInst::FCMP_OEQ:
    return ARM64CC::EQ;
  case CmpInst::ICMP_SGT:
  case CmpInst::FCMP_OGT:
    return ARM64CC::GT;
  case CmpInst::ICMP_SGE:
  case CmpInst::FCMP_OGE:
    return ARM64CC::GE;
  case CmpInst::ICMP_UGT:
  case CmpInst::FCMP_UGT:
    return ARM64CC::HI;
  case CmpInst::FCMP_OLT:
    return ARM64CC::MI;
  case CmpInst::ICMP_ULE:
  case CmpInst::FCMP_OLE:
    return ARM64CC::LS;
  case CmpInst::FCMP_ORD:
    return ARM64CC::VC;
  case CmpInst::FCMP_UNO:
    return ARM64CC::VS;
  case CmpInst::FCMP_UGE:
    return ARM64CC::PL;
  case CmpInst::ICMP_SLT:
  case CmpInst::FCMP_ULT:
    return ARM64CC::LT;
  case CmpInst::ICMP_SLE:
  case CmpInst::FCMP_ULE:
    return ARM64CC::LE;
  case CmpInst::FCMP_UNE:
  case CmpInst::ICMP_NE:
    return ARM64CC::NE;
  case CmpInst::ICMP_UGE:
    return ARM64CC::HS;
  case CmpInst::ICMP_ULT:
    return ARM64CC::LO;
  }
}

bool ARM64FastISel::SelectBranch(const Instruction *I) {
  const BranchInst *BI = cast<BranchInst>(I);
  MachineBasicBlock *TBB = FuncInfo.MBBMap[BI->getSuccessor(0)];
  MachineBasicBlock *FBB = FuncInfo.MBBMap[BI->getSuccessor(1)];

  if (const CmpInst *CI = dyn_cast<CmpInst>(BI->getCondition())) {
    if (CI->hasOneUse() && (CI->getParent() == I->getParent())) {
      // We may not handle every CC for now.
      ARM64CC::CondCode CC = getCompareCC(CI->getPredicate());
      if (CC == ARM64CC::AL)
        return false;

      // Emit the cmp.
      if (!EmitCmp(CI->getOperand(0), CI->getOperand(1), CI->isUnsigned()))
        return false;

      // Emit the branch.
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::Bcc))
          .addImm(CC)
          .addMBB(TBB);
      FuncInfo.MBB->addSuccessor(TBB);

      FastEmitBranch(FBB, DbgLoc);
      return true;
    }
  } else if (TruncInst *TI = dyn_cast<TruncInst>(BI->getCondition())) {
    MVT SrcVT;
    if (TI->hasOneUse() && TI->getParent() == I->getParent() &&
        (isLoadStoreTypeLegal(TI->getOperand(0)->getType(), SrcVT))) {
      unsigned CondReg = getRegForValue(TI->getOperand(0));
      if (CondReg == 0)
        return false;

      // Issue an extract_subreg to get the lower 32-bits.
      if (SrcVT == MVT::i64)
        CondReg = FastEmitInst_extractsubreg(MVT::i32, CondReg, /*Kill=*/true,
                                             ARM64::sub_32);

      MRI.constrainRegClass(CondReg, &ARM64::GPR32RegClass);
      unsigned ANDReg = createResultReg(&ARM64::GPR32spRegClass);
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ANDWri),
              ANDReg)
          .addReg(CondReg)
          .addImm(ARM64_AM::encodeLogicalImmediate(1, 32));
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::SUBSWri))
          .addReg(ANDReg)
          .addReg(ANDReg)
          .addImm(0)
          .addImm(0);

      unsigned CC = ARM64CC::NE;
      if (FuncInfo.MBB->isLayoutSuccessor(TBB)) {
        std::swap(TBB, FBB);
        CC = ARM64CC::EQ;
      }
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::Bcc))
          .addImm(CC)
          .addMBB(TBB);
      FuncInfo.MBB->addSuccessor(TBB);
      FastEmitBranch(FBB, DbgLoc);
      return true;
    }
  } else if (const ConstantInt *CI =
                 dyn_cast<ConstantInt>(BI->getCondition())) {
    uint64_t Imm = CI->getZExtValue();
    MachineBasicBlock *Target = (Imm == 0) ? FBB : TBB;
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::B))
        .addMBB(Target);
    FuncInfo.MBB->addSuccessor(Target);
    return true;
  }

  unsigned CondReg = getRegForValue(BI->getCondition());
  if (CondReg == 0)
    return false;

  // We've been divorced from our compare!  Our block was split, and
  // now our compare lives in a predecessor block.  We musn't
  // re-compare here, as the children of the compare aren't guaranteed
  // live across the block boundary (we *could* check for this).
  // Regardless, the compare has been done in the predecessor block,
  // and it left a value for us in a virtual register.  Ergo, we test
  // the one-bit value left in the virtual register.
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::SUBSWri),
          ARM64::WZR)
      .addReg(CondReg)
      .addImm(0)
      .addImm(0);

  unsigned CC = ARM64CC::NE;
  if (FuncInfo.MBB->isLayoutSuccessor(TBB)) {
    std::swap(TBB, FBB);
    CC = ARM64CC::EQ;
  }

  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::Bcc))
      .addImm(CC)
      .addMBB(TBB);
  FuncInfo.MBB->addSuccessor(TBB);
  FastEmitBranch(FBB, DbgLoc);
  return true;
}

bool ARM64FastISel::SelectIndirectBr(const Instruction *I) {
  const IndirectBrInst *BI = cast<IndirectBrInst>(I);
  unsigned AddrReg = getRegForValue(BI->getOperand(0));
  if (AddrReg == 0)
    return false;

  // Emit the indirect branch.
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::BR))
      .addReg(AddrReg);

  // Make sure the CFG is up-to-date.
  for (unsigned i = 0, e = BI->getNumSuccessors(); i != e; ++i)
    FuncInfo.MBB->addSuccessor(FuncInfo.MBBMap[BI->getSuccessor(i)]);

  return true;
}

bool ARM64FastISel::EmitCmp(Value *Src1Value, Value *Src2Value, bool isZExt) {
  Type *Ty = Src1Value->getType();
  EVT SrcEVT = TLI.getValueType(Ty, true);
  if (!SrcEVT.isSimple())
    return false;
  MVT SrcVT = SrcEVT.getSimpleVT();

  // Check to see if the 2nd operand is a constant that we can encode directly
  // in the compare.
  uint64_t Imm;
  bool UseImm = false;
  bool isNegativeImm = false;
  if (const ConstantInt *ConstInt = dyn_cast<ConstantInt>(Src2Value)) {
    if (SrcVT == MVT::i64 || SrcVT == MVT::i32 || SrcVT == MVT::i16 ||
        SrcVT == MVT::i8 || SrcVT == MVT::i1) {
      const APInt &CIVal = ConstInt->getValue();

      Imm = (isZExt) ? CIVal.getZExtValue() : CIVal.getSExtValue();
      if (CIVal.isNegative()) {
        isNegativeImm = true;
        Imm = -Imm;
      }
      // FIXME: We can handle more immediates using shifts.
      UseImm = ((Imm & 0xfff) == Imm);
    }
  } else if (const ConstantFP *ConstFP = dyn_cast<ConstantFP>(Src2Value)) {
    if (SrcVT == MVT::f32 || SrcVT == MVT::f64)
      if (ConstFP->isZero() && !ConstFP->isNegative())
        UseImm = true;
  }

  unsigned ZReg;
  unsigned CmpOpc;
  bool isICmp = true;
  bool needsExt = false;
  switch (SrcVT.SimpleTy) {
  default:
    return false;
  case MVT::i1:
  case MVT::i8:
  case MVT::i16:
    needsExt = true;
  // Intentional fall-through.
  case MVT::i32:
    ZReg = ARM64::WZR;
    if (UseImm)
      CmpOpc = isNegativeImm ? ARM64::ADDSWri : ARM64::SUBSWri;
    else
      CmpOpc = ARM64::SUBSWrr;
    break;
  case MVT::i64:
    ZReg = ARM64::XZR;
    if (UseImm)
      CmpOpc = isNegativeImm ? ARM64::ADDSXri : ARM64::SUBSXri;
    else
      CmpOpc = ARM64::SUBSXrr;
    break;
  case MVT::f32:
    isICmp = false;
    CmpOpc = UseImm ? ARM64::FCMPSri : ARM64::FCMPSrr;
    break;
  case MVT::f64:
    isICmp = false;
    CmpOpc = UseImm ? ARM64::FCMPDri : ARM64::FCMPDrr;
    break;
  }

  unsigned SrcReg1 = getRegForValue(Src1Value);
  if (SrcReg1 == 0)
    return false;

  unsigned SrcReg2;
  if (!UseImm) {
    SrcReg2 = getRegForValue(Src2Value);
    if (SrcReg2 == 0)
      return false;
  }

  // We have i1, i8, or i16, we need to either zero extend or sign extend.
  if (needsExt) {
    SrcReg1 = EmitIntExt(SrcVT, SrcReg1, MVT::i32, isZExt);
    if (SrcReg1 == 0)
      return false;
    if (!UseImm) {
      SrcReg2 = EmitIntExt(SrcVT, SrcReg2, MVT::i32, isZExt);
      if (SrcReg2 == 0)
        return false;
    }
  }

  if (isICmp) {
    if (UseImm)
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CmpOpc))
          .addReg(ZReg)
          .addReg(SrcReg1)
          .addImm(Imm)
          .addImm(0);
    else
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CmpOpc))
          .addReg(ZReg)
          .addReg(SrcReg1)
          .addReg(SrcReg2);
  } else {
    if (UseImm)
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CmpOpc))
          .addReg(SrcReg1);
    else
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(CmpOpc))
          .addReg(SrcReg1)
          .addReg(SrcReg2);
  }
  return true;
}

bool ARM64FastISel::SelectCmp(const Instruction *I) {
  const CmpInst *CI = cast<CmpInst>(I);

  // We may not handle every CC for now.
  ARM64CC::CondCode CC = getCompareCC(CI->getPredicate());
  if (CC == ARM64CC::AL)
    return false;

  // Emit the cmp.
  if (!EmitCmp(CI->getOperand(0), CI->getOperand(1), CI->isUnsigned()))
    return false;

  // Now set a register based on the comparison.
  ARM64CC::CondCode invertedCC = getInvertedCondCode(CC);
  unsigned ResultReg = createResultReg(&ARM64::GPR32RegClass);
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::CSINCWr),
          ResultReg)
      .addReg(ARM64::WZR)
      .addReg(ARM64::WZR)
      .addImm(invertedCC);

  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::SelectSelect(const Instruction *I) {
  const SelectInst *SI = cast<SelectInst>(I);

  EVT DestEVT = TLI.getValueType(SI->getType(), true);
  if (!DestEVT.isSimple())
    return false;

  MVT DestVT = DestEVT.getSimpleVT();
  if (DestVT != MVT::i32 && DestVT != MVT::i64 && DestVT != MVT::f32 &&
      DestVT != MVT::f64)
    return false;

  unsigned CondReg = getRegForValue(SI->getCondition());
  if (CondReg == 0)
    return false;
  unsigned TrueReg = getRegForValue(SI->getTrueValue());
  if (TrueReg == 0)
    return false;
  unsigned FalseReg = getRegForValue(SI->getFalseValue());
  if (FalseReg == 0)
    return false;


  MRI.constrainRegClass(CondReg, &ARM64::GPR32RegClass);
  unsigned ANDReg = createResultReg(&ARM64::GPR32spRegClass);
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ANDWri),
          ANDReg)
      .addReg(CondReg)
      .addImm(ARM64_AM::encodeLogicalImmediate(1, 32));

  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::SUBSWri))
      .addReg(ANDReg)
      .addReg(ANDReg)
      .addImm(0)
      .addImm(0);

  unsigned SelectOpc;
  switch (DestVT.SimpleTy) {
  default:
    return false;
  case MVT::i32:
    SelectOpc = ARM64::CSELWr;
    break;
  case MVT::i64:
    SelectOpc = ARM64::CSELXr;
    break;
  case MVT::f32:
    SelectOpc = ARM64::FCSELSrrr;
    break;
  case MVT::f64:
    SelectOpc = ARM64::FCSELDrrr;
    break;
  }

  unsigned ResultReg = createResultReg(TLI.getRegClassFor(DestVT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(SelectOpc),
          ResultReg)
      .addReg(TrueReg)
      .addReg(FalseReg)
      .addImm(ARM64CC::NE);

  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::SelectFPExt(const Instruction *I) {
  Value *V = I->getOperand(0);
  if (!I->getType()->isDoubleTy() || !V->getType()->isFloatTy())
    return false;

  unsigned Op = getRegForValue(V);
  if (Op == 0)
    return false;

  unsigned ResultReg = createResultReg(&ARM64::FPR64RegClass);
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::FCVTDSr),
          ResultReg).addReg(Op);
  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::SelectFPTrunc(const Instruction *I) {
  Value *V = I->getOperand(0);
  if (!I->getType()->isFloatTy() || !V->getType()->isDoubleTy())
    return false;

  unsigned Op = getRegForValue(V);
  if (Op == 0)
    return false;

  unsigned ResultReg = createResultReg(&ARM64::FPR32RegClass);
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::FCVTSDr),
          ResultReg).addReg(Op);
  UpdateValueMap(I, ResultReg);
  return true;
}

// FPToUI and FPToSI
bool ARM64FastISel::SelectFPToInt(const Instruction *I, bool Signed) {
  MVT DestVT;
  if (!isTypeLegal(I->getType(), DestVT) || DestVT.isVector())
    return false;

  unsigned SrcReg = getRegForValue(I->getOperand(0));
  if (SrcReg == 0)
    return false;

  EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType(), true);
  if (SrcVT == MVT::f128)
    return false;

  unsigned Opc;
  if (SrcVT == MVT::f64) {
    if (Signed)
      Opc = (DestVT == MVT::i32) ? ARM64::FCVTZSUWDr : ARM64::FCVTZSUXDr;
    else
      Opc = (DestVT == MVT::i32) ? ARM64::FCVTZUUWDr : ARM64::FCVTZUUXDr;
  } else {
    if (Signed)
      Opc = (DestVT == MVT::i32) ? ARM64::FCVTZSUWSr : ARM64::FCVTZSUXSr;
    else
      Opc = (DestVT == MVT::i32) ? ARM64::FCVTZUUWSr : ARM64::FCVTZUUXSr;
  }
  unsigned ResultReg = createResultReg(
      DestVT == MVT::i32 ? &ARM64::GPR32RegClass : &ARM64::GPR64RegClass);
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
      .addReg(SrcReg);
  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::SelectIntToFP(const Instruction *I, bool Signed) {
  MVT DestVT;
  if (!isTypeLegal(I->getType(), DestVT) || DestVT.isVector())
    return false;
  assert ((DestVT == MVT::f32 || DestVT == MVT::f64) &&
          "Unexpected value type.");

  unsigned SrcReg = getRegForValue(I->getOperand(0));
  if (SrcReg == 0)
    return false;

  EVT SrcVT = TLI.getValueType(I->getOperand(0)->getType(), true);

  // Handle sign-extension.
  if (SrcVT == MVT::i16 || SrcVT == MVT::i8 || SrcVT == MVT::i1) {
    SrcReg =
        EmitIntExt(SrcVT.getSimpleVT(), SrcReg, MVT::i32, /*isZExt*/ !Signed);
    if (SrcReg == 0)
      return false;
  }

  MRI.constrainRegClass(SrcReg, SrcVT == MVT::i64 ? &ARM64::GPR64RegClass
                                                  : &ARM64::GPR32RegClass);

  unsigned Opc;
  if (SrcVT == MVT::i64) {
    if (Signed)
      Opc = (DestVT == MVT::f32) ? ARM64::SCVTFUXSri : ARM64::SCVTFUXDri;
    else
      Opc = (DestVT == MVT::f32) ? ARM64::UCVTFUXSri : ARM64::UCVTFUXDri;
  } else {
    if (Signed)
      Opc = (DestVT == MVT::f32) ? ARM64::SCVTFUWSri : ARM64::SCVTFUWDri;
    else
      Opc = (DestVT == MVT::f32) ? ARM64::UCVTFUWSri : ARM64::UCVTFUWDri;
  }

  unsigned ResultReg = createResultReg(TLI.getRegClassFor(DestVT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
      .addReg(SrcReg);
  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::ProcessCallArgs(SmallVectorImpl<Value *> &Args,
                                    SmallVectorImpl<unsigned> &ArgRegs,
                                    SmallVectorImpl<MVT> &ArgVTs,
                                    SmallVectorImpl<ISD::ArgFlagsTy> &ArgFlags,
                                    SmallVectorImpl<unsigned> &RegArgs,
                                    CallingConv::ID CC, unsigned &NumBytes) {
  SmallVector<CCValAssign, 16> ArgLocs;
  CCState CCInfo(CC, false, *FuncInfo.MF, TM, ArgLocs, *Context);
  CCInfo.AnalyzeCallOperands(ArgVTs, ArgFlags, CCAssignFnForCall(CC));

  // Get a count of how many bytes are to be pushed on the stack.
  NumBytes = CCInfo.getNextStackOffset();

  // Issue CALLSEQ_START
  unsigned AdjStackDown = TII.getCallFrameSetupOpcode();
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(AdjStackDown))
      .addImm(NumBytes);

  // Process the args.
  for (unsigned i = 0, e = ArgLocs.size(); i != e; ++i) {
    CCValAssign &VA = ArgLocs[i];
    unsigned Arg = ArgRegs[VA.getValNo()];
    MVT ArgVT = ArgVTs[VA.getValNo()];

    // Handle arg promotion: SExt, ZExt, AExt.
    switch (VA.getLocInfo()) {
    case CCValAssign::Full:
      break;
    case CCValAssign::SExt: {
      MVT DestVT = VA.getLocVT();
      MVT SrcVT = ArgVT;
      Arg = EmitIntExt(SrcVT, Arg, DestVT, /*isZExt*/ false);
      if (Arg == 0)
        return false;
      ArgVT = DestVT;
      break;
    }
    case CCValAssign::AExt:
    // Intentional fall-through.
    case CCValAssign::ZExt: {
      MVT DestVT = VA.getLocVT();
      MVT SrcVT = ArgVT;
      Arg = EmitIntExt(SrcVT, Arg, DestVT, /*isZExt*/ true);
      if (Arg == 0)
        return false;
      ArgVT = DestVT;
      break;
    }
    default:
      llvm_unreachable("Unknown arg promotion!");
    }

    // Now copy/store arg to correct locations.
    if (VA.isRegLoc() && !VA.needsCustom()) {
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
              TII.get(TargetOpcode::COPY), VA.getLocReg()).addReg(Arg);
      RegArgs.push_back(VA.getLocReg());
    } else if (VA.needsCustom()) {
      // FIXME: Handle custom args.
      return false;
    } else {
      assert(VA.isMemLoc() && "Assuming store on stack.");

      // Need to store on the stack.
      unsigned ArgSize = VA.getLocVT().getSizeInBits() / 8;

      unsigned BEAlign = 0;
      if (ArgSize < 8 && !Subtarget->isLittleEndian())
        BEAlign = 8 - ArgSize;

      Address Addr;
      Addr.setKind(Address::RegBase);
      Addr.setReg(ARM64::SP);
      Addr.setOffset(VA.getLocMemOffset() + BEAlign);

      if (!EmitStore(ArgVT, Arg, Addr))
        return false;
    }
  }
  return true;
}

bool ARM64FastISel::FinishCall(MVT RetVT, SmallVectorImpl<unsigned> &UsedRegs,
                               const Instruction *I, CallingConv::ID CC,
                               unsigned &NumBytes) {
  // Issue CALLSEQ_END
  unsigned AdjStackUp = TII.getCallFrameDestroyOpcode();
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(AdjStackUp))
      .addImm(NumBytes)
      .addImm(0);

  // Now the return value.
  if (RetVT != MVT::isVoid) {
    SmallVector<CCValAssign, 16> RVLocs;
    CCState CCInfo(CC, false, *FuncInfo.MF, TM, RVLocs, *Context);
    CCInfo.AnalyzeCallResult(RetVT, CCAssignFnForCall(CC));

    // Only handle a single return value.
    if (RVLocs.size() != 1)
      return false;

    // Copy all of the result registers out of their specified physreg.
    MVT CopyVT = RVLocs[0].getValVT();
    unsigned ResultReg = createResultReg(TLI.getRegClassFor(CopyVT));
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
            TII.get(TargetOpcode::COPY),
            ResultReg).addReg(RVLocs[0].getLocReg());
    UsedRegs.push_back(RVLocs[0].getLocReg());

    // Finally update the result.
    UpdateValueMap(I, ResultReg);
  }

  return true;
}

bool ARM64FastISel::SelectCall(const Instruction *I,
                               const char *IntrMemName = nullptr) {
  const CallInst *CI = cast<CallInst>(I);
  const Value *Callee = CI->getCalledValue();

  // Don't handle inline asm or intrinsics.
  if (isa<InlineAsm>(Callee))
    return false;

  // Only handle global variable Callees.
  const GlobalValue *GV = dyn_cast<GlobalValue>(Callee);
  if (!GV)
    return false;

  // Check the calling convention.
  ImmutableCallSite CS(CI);
  CallingConv::ID CC = CS.getCallingConv();

  // Let SDISel handle vararg functions.
  PointerType *PT = cast<PointerType>(CS.getCalledValue()->getType());
  FunctionType *FTy = cast<FunctionType>(PT->getElementType());
  if (FTy->isVarArg())
    return false;

  // Handle *simple* calls for now.
  MVT RetVT;
  Type *RetTy = I->getType();
  if (RetTy->isVoidTy())
    RetVT = MVT::isVoid;
  else if (!isTypeLegal(RetTy, RetVT))
    return false;

  // Set up the argument vectors.
  SmallVector<Value *, 8> Args;
  SmallVector<unsigned, 8> ArgRegs;
  SmallVector<MVT, 8> ArgVTs;
  SmallVector<ISD::ArgFlagsTy, 8> ArgFlags;
  Args.reserve(CS.arg_size());
  ArgRegs.reserve(CS.arg_size());
  ArgVTs.reserve(CS.arg_size());
  ArgFlags.reserve(CS.arg_size());

  for (ImmutableCallSite::arg_iterator i = CS.arg_begin(), e = CS.arg_end();
       i != e; ++i) {
    // If we're lowering a memory intrinsic instead of a regular call, skip the
    // last two arguments, which shouldn't be passed to the underlying function.
    if (IntrMemName && e - i <= 2)
      break;

    unsigned Arg = getRegForValue(*i);
    if (Arg == 0)
      return false;

    ISD::ArgFlagsTy Flags;
    unsigned AttrInd = i - CS.arg_begin() + 1;
    if (CS.paramHasAttr(AttrInd, Attribute::SExt))
      Flags.setSExt();
    if (CS.paramHasAttr(AttrInd, Attribute::ZExt))
      Flags.setZExt();

    // FIXME: Only handle *easy* calls for now.
    if (CS.paramHasAttr(AttrInd, Attribute::InReg) ||
        CS.paramHasAttr(AttrInd, Attribute::StructRet) ||
        CS.paramHasAttr(AttrInd, Attribute::Nest) ||
        CS.paramHasAttr(AttrInd, Attribute::ByVal))
      return false;

    MVT ArgVT;
    Type *ArgTy = (*i)->getType();
    if (!isTypeLegal(ArgTy, ArgVT) &&
        !(ArgVT == MVT::i1 || ArgVT == MVT::i8 || ArgVT == MVT::i16))
      return false;

    // We don't handle vector parameters yet.
    if (ArgVT.isVector() || ArgVT.getSizeInBits() > 64)
      return false;

    unsigned OriginalAlignment = DL.getABITypeAlignment(ArgTy);
    Flags.setOrigAlign(OriginalAlignment);

    Args.push_back(*i);
    ArgRegs.push_back(Arg);
    ArgVTs.push_back(ArgVT);
    ArgFlags.push_back(Flags);
  }

  // Handle the arguments now that we've gotten them.
  SmallVector<unsigned, 4> RegArgs;
  unsigned NumBytes;
  if (!ProcessCallArgs(Args, ArgRegs, ArgVTs, ArgFlags, RegArgs, CC, NumBytes))
    return false;

  // Issue the call.
  MachineInstrBuilder MIB;
  MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::BL));
  if (!IntrMemName)
    MIB.addGlobalAddress(GV, 0, 0);
  else
    MIB.addExternalSymbol(IntrMemName, 0);

  // Add implicit physical register uses to the call.
  for (unsigned i = 0, e = RegArgs.size(); i != e; ++i)
    MIB.addReg(RegArgs[i], RegState::Implicit);

  // Add a register mask with the call-preserved registers.
  // Proper defs for return values will be added by setPhysRegsDeadExcept().
  MIB.addRegMask(TRI.getCallPreservedMask(CS.getCallingConv()));

  // Finish off the call including any return values.
  SmallVector<unsigned, 4> UsedRegs;
  if (!FinishCall(RetVT, UsedRegs, I, CC, NumBytes))
    return false;

  // Set all unused physreg defs as dead.
  static_cast<MachineInstr *>(MIB)->setPhysRegsDeadExcept(UsedRegs, TRI);

  return true;
}

bool ARM64FastISel::IsMemCpySmall(uint64_t Len, unsigned Alignment) {
  if (Alignment)
    return Len / Alignment <= 4;
  else
    return Len < 32;
}

bool ARM64FastISel::TryEmitSmallMemCpy(Address Dest, Address Src, uint64_t Len,
                                       unsigned Alignment) {
  // Make sure we don't bloat code by inlining very large memcpy's.
  if (!IsMemCpySmall(Len, Alignment))
    return false;

  int64_t UnscaledOffset = 0;
  Address OrigDest = Dest;
  Address OrigSrc = Src;

  while (Len) {
    MVT VT;
    if (!Alignment || Alignment >= 8) {
      if (Len >= 8)
        VT = MVT::i64;
      else if (Len >= 4)
        VT = MVT::i32;
      else if (Len >= 2)
        VT = MVT::i16;
      else {
        VT = MVT::i8;
      }
    } else {
      // Bound based on alignment.
      if (Len >= 4 && Alignment == 4)
        VT = MVT::i32;
      else if (Len >= 2 && Alignment == 2)
        VT = MVT::i16;
      else {
        VT = MVT::i8;
      }
    }

    bool RV;
    unsigned ResultReg;
    RV = EmitLoad(VT, ResultReg, Src);
    assert(RV == true && "Should be able to handle this load.");
    RV = EmitStore(VT, ResultReg, Dest);
    assert(RV == true && "Should be able to handle this store.");
    (void)RV;

    int64_t Size = VT.getSizeInBits() / 8;
    Len -= Size;
    UnscaledOffset += Size;

    // We need to recompute the unscaled offset for each iteration.
    Dest.setOffset(OrigDest.getOffset() + UnscaledOffset);
    Src.setOffset(OrigSrc.getOffset() + UnscaledOffset);
  }

  return true;
}

bool ARM64FastISel::SelectIntrinsicCall(const IntrinsicInst &I) {
  // FIXME: Handle more intrinsics.
  switch (I.getIntrinsicID()) {
  default:
    return false;
  case Intrinsic::memcpy:
  case Intrinsic::memmove: {
    const MemTransferInst &MTI = cast<MemTransferInst>(I);
    // Don't handle volatile.
    if (MTI.isVolatile())
      return false;

    // Disable inlining for memmove before calls to ComputeAddress.  Otherwise,
    // we would emit dead code because we don't currently handle memmoves.
    bool isMemCpy = (I.getIntrinsicID() == Intrinsic::memcpy);
    if (isa<ConstantInt>(MTI.getLength()) && isMemCpy) {
      // Small memcpy's are common enough that we want to do them without a call
      // if possible.
      uint64_t Len = cast<ConstantInt>(MTI.getLength())->getZExtValue();
      unsigned Alignment = MTI.getAlignment();
      if (IsMemCpySmall(Len, Alignment)) {
        Address Dest, Src;
        if (!ComputeAddress(MTI.getRawDest(), Dest) ||
            !ComputeAddress(MTI.getRawSource(), Src))
          return false;
        if (TryEmitSmallMemCpy(Dest, Src, Len, Alignment))
          return true;
      }
    }

    if (!MTI.getLength()->getType()->isIntegerTy(64))
      return false;

    if (MTI.getSourceAddressSpace() > 255 || MTI.getDestAddressSpace() > 255)
      // Fast instruction selection doesn't support the special
      // address spaces.
      return false;

    const char *IntrMemName = isa<MemCpyInst>(I) ? "memcpy" : "memmove";
    return SelectCall(&I, IntrMemName);
  }
  case Intrinsic::memset: {
    const MemSetInst &MSI = cast<MemSetInst>(I);
    // Don't handle volatile.
    if (MSI.isVolatile())
      return false;

    if (!MSI.getLength()->getType()->isIntegerTy(64))
      return false;

    if (MSI.getDestAddressSpace() > 255)
      // Fast instruction selection doesn't support the special
      // address spaces.
      return false;

    return SelectCall(&I, "memset");
  }
  case Intrinsic::trap: {
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::BRK))
        .addImm(1);
    return true;
  }
  }
  return false;
}

bool ARM64FastISel::SelectRet(const Instruction *I) {
  const ReturnInst *Ret = cast<ReturnInst>(I);
  const Function &F = *I->getParent()->getParent();

  if (!FuncInfo.CanLowerReturn)
    return false;

  if (F.isVarArg())
    return false;

  // Build a list of return value registers.
  SmallVector<unsigned, 4> RetRegs;

  if (Ret->getNumOperands() > 0) {
    CallingConv::ID CC = F.getCallingConv();
    SmallVector<ISD::OutputArg, 4> Outs;
    GetReturnInfo(F.getReturnType(), F.getAttributes(), Outs, TLI);

    // Analyze operands of the call, assigning locations to each operand.
    SmallVector<CCValAssign, 16> ValLocs;
    CCState CCInfo(CC, F.isVarArg(), *FuncInfo.MF, TM, ValLocs,
                   I->getContext());
    CCAssignFn *RetCC = CC == CallingConv::WebKit_JS ? RetCC_ARM64_WebKit_JS
                                                     : RetCC_ARM64_AAPCS;
    CCInfo.AnalyzeReturn(Outs, RetCC);

    // Only handle a single return value for now.
    if (ValLocs.size() != 1)
      return false;

    CCValAssign &VA = ValLocs[0];
    const Value *RV = Ret->getOperand(0);

    // Don't bother handling odd stuff for now.
    if (VA.getLocInfo() != CCValAssign::Full)
      return false;
    // Only handle register returns for now.
    if (!VA.isRegLoc())
      return false;
    unsigned Reg = getRegForValue(RV);
    if (Reg == 0)
      return false;

    unsigned SrcReg = Reg + VA.getValNo();
    unsigned DestReg = VA.getLocReg();
    // Avoid a cross-class copy. This is very unlikely.
    if (!MRI.getRegClass(SrcReg)->contains(DestReg))
      return false;

    EVT RVEVT = TLI.getValueType(RV->getType());
    if (!RVEVT.isSimple())
      return false;

    // Vectors (of > 1 lane) in big endian need tricky handling.
    if (RVEVT.isVector() && RVEVT.getVectorNumElements() > 1)
      return false;

    MVT RVVT = RVEVT.getSimpleVT();
    if (RVVT == MVT::f128)
      return false;
    MVT DestVT = VA.getValVT();
    // Special handling for extended integers.
    if (RVVT != DestVT) {
      if (RVVT != MVT::i1 && RVVT != MVT::i8 && RVVT != MVT::i16)
        return false;

      if (!Outs[0].Flags.isZExt() && !Outs[0].Flags.isSExt())
        return false;

      bool isZExt = Outs[0].Flags.isZExt();
      SrcReg = EmitIntExt(RVVT, SrcReg, DestVT, isZExt);
      if (SrcReg == 0)
        return false;
    }

    // Make the copy.
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
            TII.get(TargetOpcode::COPY), DestReg).addReg(SrcReg);

    // Add register to return instruction.
    RetRegs.push_back(VA.getLocReg());
  }

  MachineInstrBuilder MIB = BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
                                    TII.get(ARM64::RET_ReallyLR));
  for (unsigned i = 0, e = RetRegs.size(); i != e; ++i)
    MIB.addReg(RetRegs[i], RegState::Implicit);
  return true;
}

bool ARM64FastISel::SelectTrunc(const Instruction *I) {
  Type *DestTy = I->getType();
  Value *Op = I->getOperand(0);
  Type *SrcTy = Op->getType();

  EVT SrcEVT = TLI.getValueType(SrcTy, true);
  EVT DestEVT = TLI.getValueType(DestTy, true);
  if (!SrcEVT.isSimple())
    return false;
  if (!DestEVT.isSimple())
    return false;

  MVT SrcVT = SrcEVT.getSimpleVT();
  MVT DestVT = DestEVT.getSimpleVT();

  if (SrcVT != MVT::i64 && SrcVT != MVT::i32 && SrcVT != MVT::i16 &&
      SrcVT != MVT::i8)
    return false;
  if (DestVT != MVT::i32 && DestVT != MVT::i16 && DestVT != MVT::i8 &&
      DestVT != MVT::i1)
    return false;

  unsigned SrcReg = getRegForValue(Op);
  if (!SrcReg)
    return false;

  // If we're truncating from i64 to a smaller non-legal type then generate an
  // AND.  Otherwise, we know the high bits are undefined and a truncate doesn't
  // generate any code.
  if (SrcVT == MVT::i64) {
    uint64_t Mask = 0;
    switch (DestVT.SimpleTy) {
    default:
      // Trunc i64 to i32 is handled by the target-independent fast-isel.
      return false;
    case MVT::i1:
      Mask = 0x1;
      break;
    case MVT::i8:
      Mask = 0xff;
      break;
    case MVT::i16:
      Mask = 0xffff;
      break;
    }
    // Issue an extract_subreg to get the lower 32-bits.
    unsigned Reg32 = FastEmitInst_extractsubreg(MVT::i32, SrcReg, /*Kill=*/true,
                                                ARM64::sub_32);
    MRI.constrainRegClass(Reg32, &ARM64::GPR32RegClass);
    // Create the AND instruction which performs the actual truncation.
    unsigned ANDReg = createResultReg(&ARM64::GPR32spRegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ANDWri),
            ANDReg)
        .addReg(Reg32)
        .addImm(ARM64_AM::encodeLogicalImmediate(Mask, 32));
    SrcReg = ANDReg;
  }

  UpdateValueMap(I, SrcReg);
  return true;
}

unsigned ARM64FastISel::Emiti1Ext(unsigned SrcReg, MVT DestVT, bool isZExt) {
  assert((DestVT == MVT::i8 || DestVT == MVT::i16 || DestVT == MVT::i32 ||
          DestVT == MVT::i64) &&
         "Unexpected value type.");
  // Handle i8 and i16 as i32.
  if (DestVT == MVT::i8 || DestVT == MVT::i16)
    DestVT = MVT::i32;

  if (isZExt) {
    MRI.constrainRegClass(SrcReg, &ARM64::GPR32RegClass);
    unsigned ResultReg = createResultReg(&ARM64::GPR32spRegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::ANDWri),
            ResultReg)
        .addReg(SrcReg)
        .addImm(ARM64_AM::encodeLogicalImmediate(1, 32));

    if (DestVT == MVT::i64) {
      // We're ZExt i1 to i64.  The ANDWri Wd, Ws, #1 implicitly clears the
      // upper 32 bits.  Emit a SUBREG_TO_REG to extend from Wd to Xd.
      unsigned Reg64 = MRI.createVirtualRegister(&ARM64::GPR64RegClass);
      BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
              TII.get(ARM64::SUBREG_TO_REG), Reg64)
          .addImm(0)
          .addReg(ResultReg)
          .addImm(ARM64::sub_32);
      ResultReg = Reg64;
    }
    return ResultReg;
  } else {
    if (DestVT == MVT::i64) {
      // FIXME: We're SExt i1 to i64.
      return 0;
    }
    unsigned ResultReg = createResultReg(&ARM64::GPR32RegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(ARM64::SBFMWri),
            ResultReg)
        .addReg(SrcReg)
        .addImm(0)
        .addImm(0);
    return ResultReg;
  }
}

unsigned ARM64FastISel::EmitIntExt(MVT SrcVT, unsigned SrcReg, MVT DestVT,
                                   bool isZExt) {
  assert(DestVT != MVT::i1 && "ZeroExt/SignExt an i1?");
  unsigned Opc;
  unsigned Imm = 0;

  switch (SrcVT.SimpleTy) {
  default:
    return 0;
  case MVT::i1:
    return Emiti1Ext(SrcReg, DestVT, isZExt);
  case MVT::i8:
    if (DestVT == MVT::i64)
      Opc = isZExt ? ARM64::UBFMXri : ARM64::SBFMXri;
    else
      Opc = isZExt ? ARM64::UBFMWri : ARM64::SBFMWri;
    Imm = 7;
    break;
  case MVT::i16:
    if (DestVT == MVT::i64)
      Opc = isZExt ? ARM64::UBFMXri : ARM64::SBFMXri;
    else
      Opc = isZExt ? ARM64::UBFMWri : ARM64::SBFMWri;
    Imm = 15;
    break;
  case MVT::i32:
    assert(DestVT == MVT::i64 && "IntExt i32 to i32?!?");
    Opc = isZExt ? ARM64::UBFMXri : ARM64::SBFMXri;
    Imm = 31;
    break;
  }

  // Handle i8 and i16 as i32.
  if (DestVT == MVT::i8 || DestVT == MVT::i16)
    DestVT = MVT::i32;
  else if (DestVT == MVT::i64) {
    unsigned Src64 = MRI.createVirtualRegister(&ARM64::GPR64RegClass);
    BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc,
            TII.get(ARM64::SUBREG_TO_REG), Src64)
        .addImm(0)
        .addReg(SrcReg)
        .addImm(ARM64::sub_32);
    SrcReg = Src64;
  }

  unsigned ResultReg = createResultReg(TLI.getRegClassFor(DestVT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
      .addReg(SrcReg)
      .addImm(0)
      .addImm(Imm);

  return ResultReg;
}

bool ARM64FastISel::SelectIntExt(const Instruction *I) {
  // On ARM, in general, integer casts don't involve legal types; this code
  // handles promotable integers.  The high bits for a type smaller than
  // the register size are assumed to be undefined.
  Type *DestTy = I->getType();
  Value *Src = I->getOperand(0);
  Type *SrcTy = Src->getType();

  bool isZExt = isa<ZExtInst>(I);
  unsigned SrcReg = getRegForValue(Src);
  if (!SrcReg)
    return false;

  EVT SrcEVT = TLI.getValueType(SrcTy, true);
  EVT DestEVT = TLI.getValueType(DestTy, true);
  if (!SrcEVT.isSimple())
    return false;
  if (!DestEVT.isSimple())
    return false;

  MVT SrcVT = SrcEVT.getSimpleVT();
  MVT DestVT = DestEVT.getSimpleVT();
  unsigned ResultReg = EmitIntExt(SrcVT, SrcReg, DestVT, isZExt);
  if (ResultReg == 0)
    return false;
  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::SelectRem(const Instruction *I, unsigned ISDOpcode) {
  EVT DestEVT = TLI.getValueType(I->getType(), true);
  if (!DestEVT.isSimple())
    return false;

  MVT DestVT = DestEVT.getSimpleVT();
  if (DestVT != MVT::i64 && DestVT != MVT::i32)
    return false;

  unsigned DivOpc;
  bool is64bit = (DestVT == MVT::i64);
  switch (ISDOpcode) {
  default:
    return false;
  case ISD::SREM:
    DivOpc = is64bit ? ARM64::SDIVXr : ARM64::SDIVWr;
    break;
  case ISD::UREM:
    DivOpc = is64bit ? ARM64::UDIVXr : ARM64::UDIVWr;
    break;
  }
  unsigned MSubOpc = is64bit ? ARM64::MSUBXrrr : ARM64::MSUBWrrr;
  unsigned Src0Reg = getRegForValue(I->getOperand(0));
  if (!Src0Reg)
    return false;

  unsigned Src1Reg = getRegForValue(I->getOperand(1));
  if (!Src1Reg)
    return false;

  unsigned QuotReg = createResultReg(TLI.getRegClassFor(DestVT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(DivOpc), QuotReg)
      .addReg(Src0Reg)
      .addReg(Src1Reg);
  // The remainder is computed as numerator - (quotient * denominator) using the
  // MSUB instruction.
  unsigned ResultReg = createResultReg(TLI.getRegClassFor(DestVT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(MSubOpc), ResultReg)
      .addReg(QuotReg)
      .addReg(Src1Reg)
      .addReg(Src0Reg);
  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::SelectMul(const Instruction *I) {
  EVT SrcEVT = TLI.getValueType(I->getOperand(0)->getType(), true);
  if (!SrcEVT.isSimple())
    return false;
  MVT SrcVT = SrcEVT.getSimpleVT();

  // Must be simple value type.  Don't handle vectors.
  if (SrcVT != MVT::i64 && SrcVT != MVT::i32 && SrcVT != MVT::i16 &&
      SrcVT != MVT::i8)
    return false;

  unsigned Opc;
  unsigned ZReg;
  switch (SrcVT.SimpleTy) {
  default:
    return false;
  case MVT::i8:
  case MVT::i16:
  case MVT::i32:
    ZReg = ARM64::WZR;
    Opc = ARM64::MADDWrrr;
    break;
  case MVT::i64:
    ZReg = ARM64::XZR;
    Opc = ARM64::MADDXrrr;
    break;
  }

  unsigned Src0Reg = getRegForValue(I->getOperand(0));
  if (!Src0Reg)
    return false;

  unsigned Src1Reg = getRegForValue(I->getOperand(1));
  if (!Src1Reg)
    return false;

  // Create the base instruction, then add the operands.
  unsigned ResultReg = createResultReg(TLI.getRegClassFor(SrcVT));
  BuildMI(*FuncInfo.MBB, FuncInfo.InsertPt, DbgLoc, TII.get(Opc), ResultReg)
      .addReg(Src0Reg)
      .addReg(Src1Reg)
      .addReg(ZReg);
  UpdateValueMap(I, ResultReg);
  return true;
}

bool ARM64FastISel::TargetSelectInstruction(const Instruction *I) {
  switch (I->getOpcode()) {
  default:
    break;
  case Instruction::Load:
    return SelectLoad(I);
  case Instruction::Store:
    return SelectStore(I);
  case Instruction::Br:
    return SelectBranch(I);
  case Instruction::IndirectBr:
    return SelectIndirectBr(I);
  case Instruction::FCmp:
  case Instruction::ICmp:
    return SelectCmp(I);
  case Instruction::Select:
    return SelectSelect(I);
  case Instruction::FPExt:
    return SelectFPExt(I);
  case Instruction::FPTrunc:
    return SelectFPTrunc(I);
  case Instruction::FPToSI:
    return SelectFPToInt(I, /*Signed=*/true);
  case Instruction::FPToUI:
    return SelectFPToInt(I, /*Signed=*/false);
  case Instruction::SIToFP:
    return SelectIntToFP(I, /*Signed=*/true);
  case Instruction::UIToFP:
    return SelectIntToFP(I, /*Signed=*/false);
  case Instruction::SRem:
    return SelectRem(I, ISD::SREM);
  case Instruction::URem:
    return SelectRem(I, ISD::UREM);
  case Instruction::Call:
    if (const IntrinsicInst *II = dyn_cast<IntrinsicInst>(I))
      return SelectIntrinsicCall(*II);
    return SelectCall(I);
  case Instruction::Ret:
    return SelectRet(I);
  case Instruction::Trunc:
    return SelectTrunc(I);
  case Instruction::ZExt:
  case Instruction::SExt:
    return SelectIntExt(I);
  case Instruction::Mul:
    // FIXME: This really should be handled by the target-independent selector.
    return SelectMul(I);
  }
  return false;
  // Silence warnings.
  (void)&CC_ARM64_DarwinPCS_VarArg;
}

namespace llvm {
llvm::FastISel *ARM64::createFastISel(FunctionLoweringInfo &funcInfo,
                                      const TargetLibraryInfo *libInfo) {
  return new ARM64FastISel(funcInfo, libInfo);
}
}