C++ MachineBasicBlock::getLastNonDebugInstr方法代码示例

void C65FrameLowering::emitEpilogue(MachineFunction &MF,
                                    MachineBasicBlock &MBB) const {
  const C65Subtarget &STI = MF.getSubtarget<C65Subtarget>();
  const C65RegisterInfo &RegInfo = *STI.getRegisterInfo();
  const TargetInstrInfo &TII = *STI.getInstrInfo();
  const MachineFrameInfo &MFI = MF.getFrameInfo();
  C65MachineFunctionInfo &FuncInfo = *MF.getInfo<C65MachineFunctionInfo>();

  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();

  int Size = (int)MFI.getStackSize()
    + (int)FuncInfo.getBytesToPopOnReturn();
  bool Is16Bit = STI.has65802();
  unsigned FramePtr = RegInfo.getFrameRegister(MF);

  assert((MBBI->getOpcode() == C65::RTS ||
          MBBI->getOpcode() == C65::RTL) &&
         "Can only put epilogue before 'RTS' or 'RTL' instruction!");

  if (Size)
    emitSAdjustment(MF, MBB, MBBI, Size);

  if (hasFP(MF)) {
    // Restore the frame pointer.
    if (FramePtr == C65::X || FramePtr == C65::XL)
      BuildMI(MBB, MBBI, DL, TII.get(Is16Bit ? C65::PLX16 : C65::PLX8));
    else
      llvm_unreachable("Only X may be a frame pointer.");
  }
}

void MipsSEFrameLowering::emitEpilogue(MachineFunction &MF,
                                       MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  const MipsSEInstrInfo &TII =
    *static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();
  unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
  unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
  unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
  unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;

  // if framepointer enabled, restore the stack pointer.
  if (hasFP(MF)) {
    // Find the first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;

    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    // Insert instruction "move $sp, $fp" at this location.
    BuildMI(MBB, I, dl, TII.get(ADDu), SP).addReg(FP).addReg(ZERO);
  }

  // Get the number of bytes from FrameInfo
  uint64_t StackSize = MFI->getStackSize();

  if (!StackSize)
    return;

  // Adjust stack.
  TII.adjustStackPtr(SP, StackSize, MBB, MBBI);
}

void NyuziFrameLowering::emitEpilogue(MachineFunction &MF,
                                      MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI = MF.getFrameInfo();
  const NyuziInstrInfo &TII =
      *static_cast<const NyuziInstrInfo *>(MF.getSubtarget().getInstrInfo());
  DebugLoc DL = MBBI->getDebugLoc();
  assert(MBBI->getOpcode() == Nyuzi::RET &&
         "Can only put epilog before 'retl' instruction!");

  // if framepointer enabled, restore the stack pointer.
  if (hasFP(MF)) {
    // Find the first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;
    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    BuildMI(MBB, I, DL, TII.get(Nyuzi::MOVESS))
        .addReg(Nyuzi::SP_REG)
        .addReg(Nyuzi::FP_REG);
  }

  uint64_t StackSize =
      RoundUpToAlignment(MFI->getStackSize(), getStackAlignment());
  if (!StackSize)
    return;

  TII.adjustStackPointer(MBB, MBBI, StackSize);
}

void MipsSEFrameLowering::emitInterruptEpilogueStub(
    MachineFunction &MF, MachineBasicBlock &MBB) const {

  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();
  DebugLoc DL = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();

  // Perform ISR handling like GCC
  const TargetRegisterClass *PtrRC = &Mips::GPR32RegClass;

  // Disable Interrupts.
  BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::DI), Mips::ZERO);
  BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::EHB));

  // Restore EPC
  STI.getInstrInfo()->loadRegFromStackSlot(MBB, MBBI, Mips::K1,
                                           MipsFI->getISRRegFI(0), PtrRC,
                                           STI.getRegisterInfo());
  BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MTC0), Mips::COP014)
      .addReg(Mips::K1)
      .addImm(0);

  // Restore Status
  STI.getInstrInfo()->loadRegFromStackSlot(MBB, MBBI, Mips::K1,
                                           MipsFI->getISRRegFI(1), PtrRC,
                                           STI.getRegisterInfo());
  BuildMI(MBB, MBBI, DL, STI.getInstrInfo()->get(Mips::MTC0), Mips::COP012)
      .addReg(Mips::K1)
      .addImm(0);
}

void LEGFrameLowering::emitEpilogue(MachineFunction &MF,
                                    MachineBasicBlock &MBB) const {
  // Compute the stack size, to determine if we need an epilogue at all.
  const TargetInstrInfo &TII = *MF.getSubtarget().getInstrInfo();
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  DebugLoc dl = MBBI->getDebugLoc();
  uint64_t StackSize = computeStackSize(MF);
  if (!StackSize) {
    return;
  }

  // Restore the stack pointer to what it was at the beginning of the function.
  unsigned StackReg = LEG::SP;
  unsigned OffsetReg = materializeOffset(MF, MBB, MBBI, (unsigned)StackSize);
  if (OffsetReg) {
    BuildMI(MBB, MBBI, dl, TII.get(LEG::ADDrr), StackReg)
        .addReg(StackReg)
        .addReg(OffsetReg)
        .setMIFlag(MachineInstr::FrameSetup);
  } else {
    BuildMI(MBB, MBBI, dl, TII.get(LEG::ADDri), StackReg)
        .addReg(StackReg)
        .addImm(StackSize)
        .setMIFlag(MachineInstr::FrameSetup);
  }
}

void VideoCore4FrameLowering::emitEpilogue(MachineFunction &MF,
                                         MachineBasicBlock &MBB) const {
	MachineFrameInfo* MFI = MF.getFrameInfo();

	const VideoCore4InstrInfo& TII = *static_cast<const VideoCore4InstrInfo*>(
				MF.getTarget().getInstrInfo());
	const VideoCore4RegisterInfo& RI = *static_cast<const VideoCore4RegisterInfo*>(
				MF.getTarget().getRegisterInfo());
	MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
	DebugLoc dl = MBBI != MBB.end() ? MBBI->getDebugLoc() : DebugLoc();

	/* Check the return opcode. */
	if (MBBI->getOpcode() != VideoCore4::RET)
		llvm_unreachable("can only insert epilog into returning blocks");

	if (hasFP(MF))
	{
		//BuildMI(MBB, MBBI, dl, TII.get(VideoCore4::MOV_R), VideoCore4::SP)
		//	.addReg(VideoCore4::R6);
	}

	int stacksize = (int) MFI->getStackSize();

	if (hasFP(MF))
		stacksize += 4;

	TII.adjustStackPtr(stacksize, MBB, MBBI);
}

unsigned ARCInstrInfo::removeBranch(MachineBasicBlock &MBB,
                                    int *BytesRemoved) const {
  assert(!BytesRemoved && "Code size not handled");
  MachineBasicBlock::iterator I = MBB.getLastNonDebugInstr();
  if (I == MBB.end())
    return 0;

  if (!isUncondBranchOpcode(I->getOpcode()) &&
      !isCondBranchOpcode(I->getOpcode()))
    return 0;

  // Remove the branch.
  I->eraseFromParent();

  I = MBB.end();

  if (I == MBB.begin())
    return 1;
  --I;
  if (!isCondBranchOpcode(I->getOpcode()))
    return 1;

  // Remove the branch.
  I->eraseFromParent();
  return 2;
}

void Cpu0FrameLowering::emitEpilogue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  Cpu0FunctionInfo *Cpu0FI = MF.getInfo<Cpu0FunctionInfo>();
  const Cpu0InstrInfo &TII =
    *static_cast<const Cpu0InstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();
  unsigned SP = Cpu0::SP;
  unsigned ADDiu = Cpu0::ADDiu;

  // Get the number of bytes from FrameInfo
  uint64_t StackSize = MFI->getStackSize();

  if (!StackSize)
    return;

  // Adjust stack.
  if (isInt<16>(StackSize)) // addiu sp, sp, (stacksize)
    BuildMI(MBB, MBBI, dl, TII.get(ADDiu), SP).addReg(SP).addImm(StackSize);
  else { // Expand immediate that doesn't fit in 16-bit.
    Cpu0FI->setEmitNOAT();
    expandLargeImm(SP, StackSize, TII, MBB, MBBI, dl);
  }
}

void XCoreFrameLowering::emitEpilogue(MachineFunction &MF,
                                     MachineBasicBlock &MBB) const {
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  const XCoreInstrInfo &TII =
    *static_cast<const XCoreInstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();

  bool FP = hasFP(MF);
  if (FP) {
    // Restore the stack pointer.
    unsigned FramePtr = XCore::R10;
    BuildMI(MBB, MBBI, dl, TII.get(XCore::SETSP_1r))
      .addReg(FramePtr);
  }

  // Work out frame sizes.
  int FrameSize = MFI->getStackSize();

  assert(FrameSize%4 == 0 && "Misaligned frame size");

  FrameSize/=4;

  bool isU6 = isImmU6(FrameSize);

  if (!isU6 && !isImmU16(FrameSize)) {
    // FIXME could emit multiple instructions.
    report_fatal_error("emitEpilogue Frame size too big: " + Twine(FrameSize));
  }

  if (FrameSize) {
    XCoreFunctionInfo *XFI = MF.getInfo<XCoreFunctionInfo>();

    if (FP) {
      // Restore R10
      int FPSpillOffset = MFI->getObjectOffset(XFI->getFPSpillSlot());
      FPSpillOffset += FrameSize*4;
      loadFromStack(MBB, MBBI, XCore::R10, FPSpillOffset, dl, TII);
    }
    bool restoreLR = XFI->getUsesLR();
    if (restoreLR && MFI->getObjectOffset(XFI->getLRSpillSlot()) != 0) {
      int LRSpillOffset = MFI->getObjectOffset(XFI->getLRSpillSlot());
      LRSpillOffset += FrameSize*4;
      loadFromStack(MBB, MBBI, XCore::LR, LRSpillOffset, dl, TII);
      restoreLR = false;
    }
    if (restoreLR) {
      // Fold prologue into return instruction
      assert(MBBI->getOpcode() == XCore::RETSP_u6
        || MBBI->getOpcode() == XCore::RETSP_lu6);
      int Opcode = (isU6) ? XCore::RETSP_u6 : XCore::RETSP_lu6;
      BuildMI(MBB, MBBI, dl, TII.get(Opcode)).addImm(FrameSize);
      MBB.erase(MBBI);
    } else {
      int Opcode = (isU6) ? XCore::LDAWSP_ru6_RRegs : XCore::LDAWSP_lru6_RRegs;
      BuildMI(MBB, MBBI, dl, TII.get(Opcode), XCore::SP).addImm(FrameSize);
    }
  }
}

void MipsSEFrameLowering::emitEpilogue(MachineFunction &MF,
                                       MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();

  const MipsSEInstrInfo &TII =
      *static_cast<const MipsSEInstrInfo *>(STI.getInstrInfo());
  const MipsRegisterInfo &RegInfo =
      *static_cast<const MipsRegisterInfo *>(STI.getRegisterInfo());

  DebugLoc DL = MBBI->getDebugLoc();
  MipsABIInfo ABI = STI.getABI();
  unsigned SP = ABI.GetStackPtr();
  unsigned FP = ABI.GetFramePtr();
  unsigned ZERO = ABI.GetNullPtr();
  unsigned MOVE = ABI.GetGPRMoveOp();

  // if framepointer enabled, restore the stack pointer.
  if (hasFP(MF)) {
    // Find the first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;

    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    // Insert instruction "move $sp, $fp" at this location.
    BuildMI(MBB, I, DL, TII.get(MOVE), SP).addReg(FP).addReg(ZERO);
  }

  if (MipsFI->callsEhReturn()) {
    const TargetRegisterClass *RC =
        ABI.ArePtrs64bit() ? &Mips::GPR64RegClass : &Mips::GPR32RegClass;

    // Find first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;
    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    // Insert instructions that restore eh data registers.
    for (int J = 0; J < 4; ++J) {
      TII.loadRegFromStackSlot(MBB, I, ABI.GetEhDataReg(J),
                               MipsFI->getEhDataRegFI(J), RC, &RegInfo);
    }
  }

  if (MF.getFunction()->hasFnAttribute("interrupt"))
    emitInterruptEpilogueStub(MF, MBB);

  // Get the number of bytes from FrameInfo
  uint64_t StackSize = MFI->getStackSize();

  if (!StackSize)
    return;

  // Adjust stack.
  TII.adjustStackPtr(SP, StackSize, MBB, MBBI);
}

void SparcFrameLowering::emitEpilogue(MachineFunction &MF,
                                  MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  const SparcInstrInfo &TII =
    *static_cast<const SparcInstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();
  assert(MBBI->getOpcode() == SP::RETL &&
         "Can only put epilog before 'retl' instruction!");
  BuildMI(MBB, MBBI, dl, TII.get(SP::RESTORErr), SP::G0).addReg(SP::G0)
    .addReg(SP::G0);
}

void MipsSEFrameLowering::emitEpilogue(MachineFunction &MF,
                                       MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  MipsFunctionInfo *MipsFI = MF.getInfo<MipsFunctionInfo>();

  const MipsSEInstrInfo &TII =
    *static_cast<const MipsSEInstrInfo*>(MF.getTarget().getInstrInfo());
  const MipsRegisterInfo &RegInfo =
    *static_cast<const MipsRegisterInfo*>(MF.getTarget().getRegisterInfo());

  DebugLoc dl = MBBI->getDebugLoc();
  unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
  unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
  unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
  unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;

  // if framepointer enabled, restore the stack pointer.
  if (hasFP(MF)) {
    // Find the first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;

    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    // Insert instruction "move $sp, $fp" at this location.
    BuildMI(MBB, I, dl, TII.get(ADDu), SP).addReg(FP).addReg(ZERO);
  }

  if (MipsFI->callsEhReturn()) {
    const TargetRegisterClass *RC = STI.isABI_N64() ?
        &Mips::GPR64RegClass : &Mips::GPR32RegClass;

    // Find first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;
    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    // Insert instructions that restore eh data registers.
    for (int J = 0; J < 4; ++J) {
      TII.loadRegFromStackSlot(MBB, I, ehDataReg(J), MipsFI->getEhDataRegFI(J),
                               RC, &RegInfo);
    }
  }

  // Get the number of bytes from FrameInfo
  uint64_t StackSize = MFI->getStackSize();

  if (!StackSize)
    return;

  // Adjust stack.
  TII.adjustStackPtr(SP, StackSize, MBB, MBBI);
}

void XTCFrameLowering::emitEpilogue(MachineFunction &MF,
                                   MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  XTCFunctionInfo *XTCFI     = MF.getInfo<XTCFunctionInfo>();
  const XTCInstrInfo &TII =
    *static_cast<const XTCInstrInfo*>(MF.getTarget().getInstrInfo());

  DebugLoc dl = MBBI->getDebugLoc();

  CallingConv::ID CallConv = MF.getFunction()->getCallingConv();

  // Get the FI's where RA and FP are saved.
  int FPOffset = XTCFI->getFPStackOffset();
  int RAOffset = XTCFI->getRAStackOffset();

  if (hasFP(MF)) {
      /* Save current FP into stack */

    //  BuildMI(MBB, MBBI, dl, TII.get(XTC::STWPREI)).addReg(XTC::r14, RegState::Kill).addReg(XTC::r15).addImm(-4);

      /* Copy from current SP */

      BuildMI(MBB, MBBI, dl, TII.get(XTC::COPY), XTC::r15).addReg(XTC::r14);

      // Mark the FramePtr as live-in in every block except the entry.
      for (MachineFunction::iterator I = llvm::next(MF.begin()), E = MF.end();
           I != E; ++I)
          I->addLiveIn(XTC::r14);
  }
  /*
  // lwi R15, R1, stack_loc
  if (MFI->adjustsStack() || requiresRA) {
    BuildMI(MBB, MBBI, dl, TII.get(XTC::LWI), XTC::R15)
    .addReg(XTC::R1).addImm(RAOffset);
    */


  // Get the number of bytes from FrameInfo
  int StackSize = (int) MFI->getStackSize();
  if (StackSize) {
    BuildMI(MBB, MBBI, dl, TII.get(XTC::ADDI), XTC::r15)
      .addReg(XTC::r15).addImm(StackSize);
  }
}

// The function epilogue should not depend on the current stack pointer!
// It should use the frame pointer only.  This is mandatory because
// of alloca; we also take advantage of it to omit stack adjustments
// before returning.
//
// Note that when we go to restore the preserved register values we must
// not try to address their slots by using offsets from the stack pointer.
// That's because the stack pointer may have been moved during the function
// execution due to a call to alloca().  Rather, we must restore all
// preserved registers via offsets from the frame pointer value.
//
// Note also that when the current frame is being "popped" (by adjusting
// the value of the stack pointer) on function exit, we must (for the
// sake of alloca) set the new value of the stack pointer based upon
// the current value of the frame pointer.  We can't just add what we
// believe to be the (static) frame size to the stack pointer because
// if we did that, and alloca() had been called during this function,
// we would end up returning *without* having fully deallocated all of
// the space grabbed by alloca.  If that happened, and a function
// containing one or more alloca() calls was called over and over again,
// then the stack would grow without limit!
//
// RET is lowered to
//      ld -4[%fp],%pc  # modify %pc (two delay slots)
// as the return address is in the stack frame and mov to pc is allowed.
// emitEpilogue emits
//      mov %fp,%sp     # restore the stack pointer
//      ld -8[%fp],%fp  # restore the caller's frame pointer
// before RET and the delay slot filler will move RET such that these
// instructions execute in the delay slots of the load to PC.
void LanaiFrameLowering::emitEpilogue(MachineFunction &MF,
                                      MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  const LanaiInstrInfo &LII =
      *static_cast<const LanaiInstrInfo *>(STI.getInstrInfo());
  DebugLoc DL = MBBI->getDebugLoc();

  // Restore the stack pointer using the callee's frame pointer value.
  BuildMI(MBB, MBBI, DL, LII.get(Lanai::ADD_I_LO), Lanai::SP)
      .addReg(Lanai::FP)
      .addImm(0);

  // Restore the frame pointer from the stack.
  BuildMI(MBB, MBBI, DL, LII.get(Lanai::LDW_RI), Lanai::FP)
      .addReg(Lanai::FP)
      .addImm(-8)
      .addImm(LPAC::ADD);
}

void MipsFrameLowering::emitEpilogue(MachineFunction &MF,
                                 MachineBasicBlock &MBB) const {
  MachineBasicBlock::iterator MBBI = MBB.getLastNonDebugInstr();
  MachineFrameInfo *MFI            = MF.getFrameInfo();
  const MipsInstrInfo &TII =
    *static_cast<const MipsInstrInfo*>(MF.getTarget().getInstrInfo());
  DebugLoc dl = MBBI->getDebugLoc();
  unsigned SP = STI.isABI_N64() ? Mips::SP_64 : Mips::SP;
  unsigned FP = STI.isABI_N64() ? Mips::FP_64 : Mips::FP;
  unsigned ZERO = STI.isABI_N64() ? Mips::ZERO_64 : Mips::ZERO;
  unsigned ADDu = STI.isABI_N64() ? Mips::DADDu : Mips::ADDu;
  unsigned ADDiu = STI.isABI_N64() ? Mips::DADDiu : Mips::ADDiu;

  // if framepointer enabled, restore the stack pointer.
  if (hasFP(MF)) {
    // Find the first instruction that restores a callee-saved register.
    MachineBasicBlock::iterator I = MBBI;

    for (unsigned i = 0; i < MFI->getCalleeSavedInfo().size(); ++i)
      --I;

    // Insert instruction "move $sp, $fp" at this location.
    BuildMI(MBB, I, dl, TII.get(ADDu), SP).addReg(FP).addReg(ZERO);
  }

  // Get the number of bytes from FrameInfo
  uint64_t StackSize = MFI->getStackSize();

  if (!StackSize)
    return;

  // Adjust stack.
  if (isInt<16>(StackSize)) // addi sp, sp, (-stacksize)
    BuildMI(MBB, MBBI, dl, TII.get(ADDiu), SP).addReg(SP).addImm(StackSize);
  else { // Expand immediate that doesn't fit in 16-bit.
    unsigned ATReg = STI.isABI_N64() ? Mips::AT_64 : Mips::AT;

    MF.getInfo<MipsFunctionInfo>()->setEmitNOAT();
    Mips::loadImmediate(StackSize, STI.isABI_N64(), TII, MBB, MBBI, dl, false,
                        0);
    BuildMI(MBB, MBBI, dl, TII.get(ADDu), SP).addReg(SP).addReg(ATReg);
  }
}