Use common code for both ARM and Thumb-2 instruction and register info.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@75067 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 4 insertions, 697 deletions

diff --git a/lib/Target/ARM/Thumb2RegisterInfo.cpp b/lib/Target/ARM/Thumb2RegisterInfo.cpp
index f5a8b82478..ebb8ce5f70 100644
--- a/lib/Target/ARM/Thumb2RegisterInfo.cpp
+++ b/lib/Target/ARM/Thumb2RegisterInfo.cpp
@@ -34,11 +34,6 @@
 #include "llvm/Support/ErrorHandling.h"
 using namespace llvm;
 
-static cl::opt<bool>
-Thumb2RegScavenging("enable-thumb2-reg-scavenging",
-                    cl::Hidden,
-                    cl::desc("Enable register scavenging on Thumb-2"));
-
 Thumb2RegisterInfo::Thumb2RegisterInfo(const ARMBaseInstrInfo &tii,
                                        const ARMSubtarget &sti)
   : ARMBaseRegisterInfo(tii, sti) {
@@ -58,699 +53,11 @@ void Thumb2RegisterInfo::emitLoadConstPool(MachineBasicBlock &MBB,
   unsigned Idx = ConstantPool->getConstantPoolIndex(C, 4);
 
   BuildMI(MBB, MBBI, dl, TII.get(ARM::t2LDRpci), DestReg)
-    .addConstantPoolIndex(Idx).addImm(Pred).addReg(PredReg);
-}
-
-const TargetRegisterClass*
-Thumb2RegisterInfo::getPhysicalRegisterRegClass(unsigned Reg, MVT VT) const {
-  if (isARMLowRegister(Reg))
-    return ARM::tGPRRegisterClass;
-  switch (Reg) {
-   default:
-    break;
-   case ARM::R8:  case ARM::R9:  case ARM::R10:  case ARM::R11:
-   case ARM::R12: case ARM::SP:  case ARM::LR:   case ARM::PC:
-    return ARM::GPRRegisterClass;
-  }
-
-  return TargetRegisterInfo::getPhysicalRegisterRegClass(Reg, VT);
-}
-
-bool
-Thumb2RegisterInfo::requiresRegisterScavenging(const MachineFunction &MF) const {
-  return Thumb2RegScavenging;
-}
-
-bool Thumb2RegisterInfo::hasReservedCallFrame(MachineFunction &MF) const {
-  const MachineFrameInfo *FFI = MF.getFrameInfo();
-  unsigned CFSize = FFI->getMaxCallFrameSize();
-  // It's not always a good idea to include the call frame as part of the
-  // stack frame. ARM (especially Thumb) has small immediate offset to
-  // address the stack frame. So a large call frame can cause poor codegen
-  // and may even makes it impossible to scavenge a register.
-  if (CFSize >= ((1 << 8) - 1) * 4 / 2) // Half of imm8 * 4
-    return false;
-
-  return !MF.getFrameInfo()->hasVarSizedObjects();
-}
-
-/// emitThumbRegPlusImmInReg - Emits a series of instructions to materialize
-/// a destreg = basereg + immediate in Thumb code. Materialize the immediate
-/// in a register using mov / mvn sequences or load the immediate from a
-/// constpool entry.
-static
-void emitThumbRegPlusImmInReg(MachineBasicBlock &MBB,
-                              MachineBasicBlock::iterator &MBBI,
-                              unsigned DestReg, unsigned BaseReg,
-                              int NumBytes, bool CanChangeCC,
-                              const TargetInstrInfo &TII,
-                              const Thumb2RegisterInfo& MRI,
-                              DebugLoc dl) {
-    bool isHigh = !isARMLowRegister(DestReg) ||
-                  (BaseReg != 0 && !isARMLowRegister(BaseReg));
-    bool isSub = false;
-    // Subtract doesn't have high register version. Load the negative value
-    // if either base or dest register is a high register. Also, if do not
-    // issue sub as part of the sequence if condition register is to be
-    // preserved.
-    if (NumBytes < 0 && !isHigh && CanChangeCC) {
-      isSub = true;
-      NumBytes = -NumBytes;
-    }
-    unsigned LdReg = DestReg;
-    if (DestReg == ARM::SP) {
-      assert(BaseReg == ARM::SP && "Unexpected!");
-      LdReg = ARM::R3;
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
-        .addReg(ARM::R3, RegState::Kill);
-    }
-
-    if (NumBytes <= 255 && NumBytes >= 0)
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg).addImm(NumBytes);
-    else if (NumBytes < 0 && NumBytes >= -255) {
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), LdReg).addImm(NumBytes);
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tNEG), LdReg)
-        .addReg(LdReg, RegState::Kill);
-    } else
-      MRI.emitLoadConstPool(MBB, MBBI, dl, LdReg, NumBytes);
-
-    // Emit add / sub.
-    int Opc = (isSub) ? ARM::tSUBrr : (isHigh ? ARM::tADDhirr : ARM::tADDrr);
-    const MachineInstrBuilder MIB = BuildMI(MBB, MBBI, dl,
-                                            TII.get(Opc), DestReg);
-    if (DestReg == ARM::SP || isSub)
-      MIB.addReg(BaseReg).addReg(LdReg, RegState::Kill);
-    else
-      MIB.addReg(LdReg).addReg(BaseReg, RegState::Kill);
-    if (DestReg == ARM::SP)
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVhir2lor), ARM::R3)
-        .addReg(ARM::R12, RegState::Kill);
-}
-
-/// calcNumMI - Returns the number of instructions required to materialize
-/// the specific add / sub r, c instruction.
-static unsigned calcNumMI(int Opc, int ExtraOpc, unsigned Bytes,
-                          unsigned NumBits, unsigned Scale) {
-  unsigned NumMIs = 0;
-  unsigned Chunk = ((1 << NumBits) - 1) * Scale;
-
-  if (Opc == ARM::tADDrSPi) {
-    unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
-    Bytes -= ThisVal;
-    NumMIs++;
-    NumBits = 8;
-    Scale = 1;  // Followed by a number of tADDi8.
-    Chunk = ((1 << NumBits) - 1) * Scale;
-  }
-
-  NumMIs += Bytes / Chunk;
-  if ((Bytes % Chunk) != 0)
-    NumMIs++;
-  if (ExtraOpc)
-    NumMIs++;
-  return NumMIs;
-}
-
-/// emitThumbRegPlusImmediate - Emits a series of instructions to materialize
-/// a destreg = basereg + immediate in Thumb code.
-static
-void emitThumbRegPlusImmediate(MachineBasicBlock &MBB,
-                               MachineBasicBlock::iterator &MBBI,
-                               unsigned DestReg, unsigned BaseReg,
-                               int NumBytes, const TargetInstrInfo &TII,
-                               const Thumb2RegisterInfo& MRI,
-                               DebugLoc dl) {
-  bool isSub = NumBytes < 0;
-  unsigned Bytes = (unsigned)NumBytes;
-  if (isSub) Bytes = -NumBytes;
-  bool isMul4 = (Bytes & 3) == 0;
-  bool isTwoAddr = false;
-  bool DstNotEqBase = false;
-  unsigned NumBits = 1;
-  unsigned Scale = 1;
-  int Opc = 0;
-  int ExtraOpc = 0;
-
-  if (DestReg == BaseReg && BaseReg == ARM::SP) {
-    assert(isMul4 && "Thumb sp inc / dec size must be multiple of 4!");
-    NumBits = 7;
-    Scale = 4;
-    Opc = isSub ? ARM::tSUBspi : ARM::tADDspi;
-    isTwoAddr = true;
-  } else if (!isSub && BaseReg == ARM::SP) {
-    // r1 = add sp, 403
-    // =>
-    // r1 = add sp, 100 * 4
-    // r1 = add r1, 3
-    if (!isMul4) {
-      Bytes &= ~3;
-      ExtraOpc = ARM::tADDi3;
-    }
-    NumBits = 8;
-    Scale = 4;
-    Opc = ARM::tADDrSPi;
-  } else {
-    // sp = sub sp, c
-    // r1 = sub sp, c
-    // r8 = sub sp, c
-    if (DestReg != BaseReg)
-      DstNotEqBase = true;
-    NumBits = 8;
-    Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
-    isTwoAddr = true;
-  }
-
-  unsigned NumMIs = calcNumMI(Opc, ExtraOpc, Bytes, NumBits, Scale);
-  unsigned Threshold = (DestReg == ARM::SP) ? 3 : 2;
-  if (NumMIs > Threshold) {
-    // This will expand into too many instructions. Load the immediate from a
-    // constpool entry.
-    emitThumbRegPlusImmInReg(MBB, MBBI, DestReg, BaseReg, NumBytes, true, TII,
-                             MRI, dl);
-    return;
-  }
-
-  if (DstNotEqBase) {
-    if (isARMLowRegister(DestReg) && isARMLowRegister(BaseReg)) {
-      // If both are low registers, emit DestReg = add BaseReg, max(Imm, 7)
-      unsigned Chunk = (1 << 3) - 1;
-      unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
-      Bytes -= ThisVal;
-      BuildMI(MBB, MBBI, dl,TII.get(isSub ? ARM::tSUBi3 : ARM::tADDi3), DestReg)
-        .addReg(BaseReg, RegState::Kill).addImm(ThisVal);
-    } else {
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVr), DestReg)
-        .addReg(BaseReg, RegState::Kill);
-    }
-    BaseReg = DestReg;
-  }
-
-  unsigned Chunk = ((1 << NumBits) - 1) * Scale;
-  while (Bytes) {
-    unsigned ThisVal = (Bytes > Chunk) ? Chunk : Bytes;
-    Bytes -= ThisVal;
-    ThisVal /= Scale;
-    // Build the new tADD / tSUB.
-    if (isTwoAddr)
-      BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
-        .addReg(DestReg).addImm(ThisVal);
-    else {
-      bool isKill = BaseReg != ARM::SP;
-      BuildMI(MBB, MBBI, dl, TII.get(Opc), DestReg)
-        .addReg(BaseReg, getKillRegState(isKill)).addImm(ThisVal);
-      BaseReg = DestReg;
-
-      if (Opc == ARM::tADDrSPi) {
-        // r4 = add sp, imm
-        // r4 = add r4, imm
-        // ...
-        NumBits = 8;
-        Scale = 1;
-        Chunk = ((1 << NumBits) - 1) * Scale;
-        Opc = isSub ? ARM::tSUBi8 : ARM::tADDi8;
-        isTwoAddr = true;
-      }
-    }
-  }
-
-  if (ExtraOpc)
-    BuildMI(MBB, MBBI, dl, TII.get(ExtraOpc), DestReg)
-      .addReg(DestReg, RegState::Kill)
-      .addImm(((unsigned)NumBytes) & 3);
-}
-
-static void emitSPUpdate(MachineBasicBlock &MBB,
-                         MachineBasicBlock::iterator &MBBI,
-                         const TargetInstrInfo &TII, DebugLoc dl,
-                         const Thumb2RegisterInfo &MRI,
-                         int NumBytes) {
-  emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, ARM::SP, NumBytes, TII,
-                            MRI, dl);
-}
-
-void Thumb2RegisterInfo::
-eliminateCallFramePseudoInstr(MachineFunction &MF, MachineBasicBlock &MBB,
-                              MachineBasicBlock::iterator I) const {
-  if (!hasReservedCallFrame(MF)) {
-    // If we have alloca, convert as follows:
-    // ADJCALLSTACKDOWN -> sub, sp, sp, amount
-    // ADJCALLSTACKUP   -> add, sp, sp, amount
-    MachineInstr *Old = I;
-    DebugLoc dl = Old->getDebugLoc();
-    unsigned Amount = Old->getOperand(0).getImm();
-    if (Amount != 0) {
-      // We need to keep the stack aligned properly.  To do this, we round the
-      // amount of space needed for the outgoing arguments up to the next
-      // alignment boundary.
-      unsigned Align = MF.getTarget().getFrameInfo()->getStackAlignment();
-      Amount = (Amount+Align-1)/Align*Align;
-
-      // Replace the pseudo instruction with a new instruction...
-      unsigned Opc = Old->getOpcode();
-      if (Opc == ARM::ADJCALLSTACKDOWN || Opc == ARM::tADJCALLSTACKDOWN) {
-        emitSPUpdate(MBB, I, TII, dl, *this, -Amount);
-      } else {
-        assert(Opc == ARM::ADJCALLSTACKUP || Opc == ARM::tADJCALLSTACKUP);
-        emitSPUpdate(MBB, I, TII, dl, *this, Amount);
-      }
-    }
-  }
-  MBB.erase(I);
-}
-
-/// emitThumbConstant - Emit a series of instructions to materialize a
-/// constant.
-static void emitThumbConstant(MachineBasicBlock &MBB,
-                              MachineBasicBlock::iterator &MBBI,
-                              unsigned DestReg, int Imm,
-                              const TargetInstrInfo &TII,
-                              const Thumb2RegisterInfo& MRI,
-                              DebugLoc dl) {
-  bool isSub = Imm < 0;
-  if (isSub) Imm = -Imm;
-
-  int Chunk = (1 << 8) - 1;
-  int ThisVal = (Imm > Chunk) ? Chunk : Imm;
-  Imm -= ThisVal;
-  BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVi8), DestReg).addImm(ThisVal);
-  if (Imm > 0)
-    emitThumbRegPlusImmediate(MBB, MBBI, DestReg, DestReg, Imm, TII, MRI, dl);
-  if (isSub)
-    BuildMI(MBB, MBBI, dl, TII.get(ARM::tNEG), DestReg)
-      .addReg(DestReg, RegState::Kill);
-}
-
-void Thumb2RegisterInfo::eliminateFrameIndex(MachineBasicBlock::iterator II,
-                                             int SPAdj, RegScavenger *RS) const{
-  unsigned i = 0;
-  MachineInstr &MI = *II;
-  MachineBasicBlock &MBB = *MI.getParent();
-  MachineFunction &MF = *MBB.getParent();
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  DebugLoc dl = MI.getDebugLoc();
-
-  while (!MI.getOperand(i).isFI()) {
-    ++i;
-    assert(i < MI.getNumOperands() && "Instr doesn't have FrameIndex operand!");
-  }
-
-  unsigned FrameReg = ARM::SP;
-  int FrameIndex = MI.getOperand(i).getIndex();
-  int Offset = MF.getFrameInfo()->getObjectOffset(FrameIndex) +
-               MF.getFrameInfo()->getStackSize() + SPAdj;
-
-  if (AFI->isGPRCalleeSavedArea1Frame(FrameIndex))
-    Offset -= AFI->getGPRCalleeSavedArea1Offset();
-  else if (AFI->isGPRCalleeSavedArea2Frame(FrameIndex))
-    Offset -= AFI->getGPRCalleeSavedArea2Offset();
-  else if (hasFP(MF)) {
-    assert(SPAdj == 0 && "Unexpected");
-    // There is alloca()'s in this function, must reference off the frame
-    // pointer instead.
-    FrameReg = getFrameRegister(MF);
-    Offset -= AFI->getFramePtrSpillOffset();
-  }
-
-  unsigned Opcode = MI.getOpcode();
-  const TargetInstrDesc &Desc = MI.getDesc();
-  unsigned AddrMode = (Desc.TSFlags & ARMII::AddrModeMask);
-
-  if (Opcode == ARM::tADDrSPi) {
-    Offset += MI.getOperand(i+1).getImm();
-
-    // Can't use tADDrSPi if it's based off the frame pointer.
-    unsigned NumBits = 0;
-    unsigned Scale = 1;
-    if (FrameReg != ARM::SP) {
-      Opcode = ARM::tADDi3;
-      MI.setDesc(TII.get(ARM::tADDi3));
-      NumBits = 3;
-    } else {
-      NumBits = 8;
-      Scale = 4;
-      assert((Offset & 3) == 0 &&
-             "Thumb add/sub sp, #imm immediate must be multiple of 4!");
-    }
-
-    if (Offset == 0) {
-      // Turn it into a move.
-      MI.setDesc(TII.get(ARM::tMOVhir2lor));
-      MI.getOperand(i).ChangeToRegister(FrameReg, false);
-      MI.RemoveOperand(i+1);
-      return;
-    }
-
-    // Common case: small offset, fits into instruction.
-    unsigned Mask = (1 << NumBits) - 1;
-    if (((Offset / Scale) & ~Mask) == 0) {
-      // Replace the FrameIndex with sp / fp
-      MI.getOperand(i).ChangeToRegister(FrameReg, false);
-      MI.getOperand(i+1).ChangeToImmediate(Offset / Scale);
-      return;
-    }
-
-    unsigned DestReg = MI.getOperand(0).getReg();
-    unsigned Bytes = (Offset > 0) ? Offset : -Offset;
-    unsigned NumMIs = calcNumMI(Opcode, 0, Bytes, NumBits, Scale);
-    // MI would expand into a large number of instructions. Don't try to
-    // simplify the immediate.
-    if (NumMIs > 2) {
-      emitThumbRegPlusImmediate(MBB, II, DestReg, FrameReg, Offset, TII,
-                                *this, dl);
-      MBB.erase(II);
-      return;
-    }
-
-    if (Offset > 0) {
-      // Translate r0 = add sp, imm to
-      // r0 = add sp, 255*4
-      // r0 = add r0, (imm - 255*4)
-      MI.getOperand(i).ChangeToRegister(FrameReg, false);
-      MI.getOperand(i+1).ChangeToImmediate(Mask);
-      Offset = (Offset - Mask * Scale);
-      MachineBasicBlock::iterator NII = next(II);
-      emitThumbRegPlusImmediate(MBB, NII, DestReg, DestReg, Offset, TII,
-                                *this, dl);
-    } else {
-      // Translate r0 = add sp, -imm to
-      // r0 = -imm (this is then translated into a series of instructons)
-      // r0 = add r0, sp
-      emitThumbConstant(MBB, II, DestReg, Offset, TII, *this, dl);
-      MI.setDesc(TII.get(ARM::tADDhirr));
-      MI.getOperand(i).ChangeToRegister(DestReg, false, false, true);
-      MI.getOperand(i+1).ChangeToRegister(FrameReg, false);
-    }
-    return;
-  } else {
-    unsigned ImmIdx = 0;
-    int InstrOffs = 0;
-    unsigned NumBits = 0;
-    unsigned Scale = 1;
-    switch (AddrMode) {
-    case ARMII::AddrModeT1_s: {
-      ImmIdx = i+1;
-      InstrOffs = MI.getOperand(ImmIdx).getImm();
-      NumBits = (FrameReg == ARM::SP) ? 8 : 5;
-      Scale = 4;
-      break;
-    }
-    default:
-      LLVM_UNREACHABLE("Unsupported addressing mode!");
-    }
-
-    Offset += InstrOffs * Scale;
-    assert((Offset & (Scale-1)) == 0 && "Can't encode this offset!");
-
-    // Common case: small offset, fits into instruction.
-    MachineOperand &ImmOp = MI.getOperand(ImmIdx);
-    int ImmedOffset = Offset / Scale;
-    unsigned Mask = (1 << NumBits) - 1;
-    if ((unsigned)Offset <= Mask * Scale) {
-      // Replace the FrameIndex with sp
-      MI.getOperand(i).ChangeToRegister(FrameReg, false);
-      ImmOp.ChangeToImmediate(ImmedOffset);
-      return;
-    }
-
-    bool isThumSpillRestore = Opcode == ARM::tRestore || Opcode == ARM::tSpill;
-    if (AddrMode == ARMII::AddrModeT1_s) {
-      // Thumb tLDRspi, tSTRspi. These will change to instructions that use
-      // a different base register.
-      NumBits = 5;
-      Mask = (1 << NumBits) - 1;
-    }
-    // If this is a thumb spill / restore, we will be using a constpool load to
-    // materialize the offset.
-    if (AddrMode == ARMII::AddrModeT1_s && isThumSpillRestore)
-      ImmOp.ChangeToImmediate(0);
-    else {
-      // Otherwise, it didn't fit. Pull in what we can to simplify the immed.
-      ImmedOffset = ImmedOffset & Mask;
-      ImmOp.ChangeToImmediate(ImmedOffset);
-      Offset &= ~(Mask*Scale);
-    }
-  }
-
-  // If we get here, the immediate doesn't fit into the instruction.  We folded
-  // as much as possible above, handle the rest, providing a register that is
-  // SP+LargeImm.
-  assert(Offset && "This code isn't needed if offset already handled!");
-
-  if (Desc.mayLoad()) {
-    // Use the destination register to materialize sp + offset.
-    unsigned TmpReg = MI.getOperand(0).getReg();
-    bool UseRR = false;
-    if (Opcode == ARM::tRestore) {
-      if (FrameReg == ARM::SP)
-        emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
-                                 Offset, false, TII, *this, dl);
-      else {
-        emitLoadConstPool(MBB, II, dl, TmpReg, Offset);
-        UseRR = true;
-      }
-    } else
-      emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
-                                *this, dl);
-    MI.setDesc(TII.get(ARM::tLDR));
-    MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
-    if (UseRR)
-      // Use [reg, reg] addrmode.
-      MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
-    else  // tLDR has an extra register operand.
-      MI.addOperand(MachineOperand::CreateReg(0, false));
-  } else if (Desc.mayStore()) {
-    // FIXME! This is horrific!!! We need register scavenging.
-    // Our temporary workaround has marked r3 unavailable. Of course, r3 is
-    // also a ABI register so it's possible that is is the register that is
-    // being storing here. If that's the case, we do the following:
-    // r12 = r2
-    // Use r2 to materialize sp + offset
-    // str r3, r2
-    // r2 = r12
-    unsigned ValReg = MI.getOperand(0).getReg();
-    unsigned TmpReg = ARM::R3;
-    bool UseRR = false;
-    if (ValReg == ARM::R3) {
-      BuildMI(MBB, II, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
-        .addReg(ARM::R2, RegState::Kill);
-      TmpReg = ARM::R2;
-    }
-    if (TmpReg == ARM::R3 && AFI->isR3LiveIn())
-      BuildMI(MBB, II, dl, TII.get(ARM::tMOVlor2hir), ARM::R12)
-        .addReg(ARM::R3, RegState::Kill);
-    if (Opcode == ARM::tSpill) {
-      if (FrameReg == ARM::SP)
-        emitThumbRegPlusImmInReg(MBB, II, TmpReg, FrameReg,
-                                 Offset, false, TII, *this, dl);
-      else {
-        emitLoadConstPool(MBB, II, dl, TmpReg, Offset);
-        UseRR = true;
-      }
-    } else
-      emitThumbRegPlusImmediate(MBB, II, TmpReg, FrameReg, Offset, TII,
-                                *this, dl);
-    MI.setDesc(TII.get(ARM::tSTR));
-    MI.getOperand(i).ChangeToRegister(TmpReg, false, false, true);
-    if (UseRR)  // Use [reg, reg] addrmode.
-      MI.addOperand(MachineOperand::CreateReg(FrameReg, false));
-    else // tSTR has an extra register operand.
-      MI.addOperand(MachineOperand::CreateReg(0, false));
-
-    MachineBasicBlock::iterator NII = next(II);
-    if (ValReg == ARM::R3)
-      BuildMI(MBB, NII, dl, TII.get(ARM::tMOVhir2lor), ARM::R2)
-        .addReg(ARM::R12, RegState::Kill);
-    if (TmpReg == ARM::R3 && AFI->isR3LiveIn())
-      BuildMI(MBB, NII, dl, TII.get(ARM::tMOVhir2lor), ARM::R3)
-        .addReg(ARM::R12, RegState::Kill);
-  } else
-    assert(false && "Unexpected opcode!");
-}
-
-void Thumb2RegisterInfo::emitPrologue(MachineFunction &MF) const {
-  MachineBasicBlock &MBB = MF.front();
-  MachineBasicBlock::iterator MBBI = MBB.begin();
-  MachineFrameInfo  *MFI = MF.getFrameInfo();
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
-  unsigned NumBytes = MFI->getStackSize();
-  const std::vector<CalleeSavedInfo> &CSI = MFI->getCalleeSavedInfo();
-  DebugLoc dl = (MBBI != MBB.end() ?
-                 MBBI->getDebugLoc() : DebugLoc::getUnknownLoc());
-
-  // Check if R3 is live in. It might have to be used as a scratch register.
-  for (MachineRegisterInfo::livein_iterator I =MF.getRegInfo().livein_begin(),
-         E = MF.getRegInfo().livein_end(); I != E; ++I) {
-    if (I->first == ARM::R3) {
-      AFI->setR3IsLiveIn(true);
-      break;
-    }
-  }
-
-  // Thumb add/sub sp, imm8 instructions implicitly multiply the offset by 4.
-  NumBytes = (NumBytes + 3) & ~3;
-  MFI->setStackSize(NumBytes);
-
-  // Determine the sizes of each callee-save spill areas and record which frame
-  // belongs to which callee-save spill areas.
-  unsigned GPRCS1Size = 0, GPRCS2Size = 0, DPRCSSize = 0;
-  int FramePtrSpillFI = 0;
-
-  if (VARegSaveSize)
-    emitSPUpdate(MBB, MBBI, TII, dl, *this, -VARegSaveSize);
-
-  if (!AFI->hasStackFrame()) {
-    if (NumBytes != 0)
-      emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
-    return;
-  }
-
-  for (unsigned i = 0, e = CSI.size(); i != e; ++i) {
-    unsigned Reg = CSI[i].getReg();
-    int FI = CSI[i].getFrameIdx();
-    switch (Reg) {
-    case ARM::R4:
-    case ARM::R5:
-    case ARM::R6:
-    case ARM::R7:
-    case ARM::LR:
-      if (Reg == FramePtr)
-        FramePtrSpillFI = FI;
-      AFI->addGPRCalleeSavedArea1Frame(FI);
-      GPRCS1Size += 4;
-      break;
-    case ARM::R8:
-    case ARM::R9:
-    case ARM::R10:
-    case ARM::R11:
-      if (Reg == FramePtr)
-        FramePtrSpillFI = FI;
-      if (STI.isTargetDarwin()) {
-        AFI->addGPRCalleeSavedArea2Frame(FI);
-        GPRCS2Size += 4;
-      } else {
-        AFI->addGPRCalleeSavedArea1Frame(FI);
-        GPRCS1Size += 4;
-      }
-      break;
-    default:
-      AFI->addDPRCalleeSavedAreaFrame(FI);
-      DPRCSSize += 8;
-    }
-  }
-
-  if (MBBI != MBB.end() && MBBI->getOpcode() == ARM::tPUSH) {
-    ++MBBI;
-    if (MBBI != MBB.end())
-      dl = MBBI->getDebugLoc();
-  }
-
-  // Darwin ABI requires FP to point to the stack slot that contains the
-  // previous FP.
-  if (STI.isTargetDarwin() || hasFP(MF)) {
-    MachineInstrBuilder MIB =
-      BuildMI(MBB, MBBI, dl, TII.get(ARM::tADDrSPi), FramePtr)
-      .addFrameIndex(FramePtrSpillFI).addImm(0);
-  }
-
-  // Determine starting offsets of spill areas.
-  unsigned DPRCSOffset  = NumBytes - (GPRCS1Size + GPRCS2Size + DPRCSSize);
-  unsigned GPRCS2Offset = DPRCSOffset + DPRCSSize;
-  unsigned GPRCS1Offset = GPRCS2Offset + GPRCS2Size;
-  AFI->setFramePtrSpillOffset(MFI->getObjectOffset(FramePtrSpillFI) + NumBytes);
-  AFI->setGPRCalleeSavedArea1Offset(GPRCS1Offset);
-  AFI->setGPRCalleeSavedArea2Offset(GPRCS2Offset);
-  AFI->setDPRCalleeSavedAreaOffset(DPRCSOffset);
-
-  NumBytes = DPRCSOffset;
-  if (NumBytes) {
-    // Insert it after all the callee-save spills.
-    emitSPUpdate(MBB, MBBI, TII, dl, *this, -NumBytes);
-  }
-
-  if (STI.isTargetELF() && hasFP(MF)) {
-    MFI->setOffsetAdjustment(MFI->getOffsetAdjustment() -
-                             AFI->getFramePtrSpillOffset());
-  }
-
-  AFI->setGPRCalleeSavedArea1Size(GPRCS1Size);
-  AFI->setGPRCalleeSavedArea2Size(GPRCS2Size);
-  AFI->setDPRCalleeSavedAreaSize(DPRCSSize);
+    .addConstantPoolIndex(Idx).addImm((int64_t)ARMCC::AL).addReg(0);
 }
 
-static bool isCalleeSavedRegister(unsigned Reg, const unsigned *CSRegs) {
-  for (unsigned i = 0; CSRegs[i]; ++i)
-    if (Reg == CSRegs[i])
-      return true;
+bool Thumb2RegisterInfo::
+requiresRegisterScavenging(const MachineFunction &MF) const {
+  // FIXME
   return false;
 }
-
-static bool isCSRestore(MachineInstr *MI, const unsigned *CSRegs) {
-  return (MI->getOpcode() == ARM::tRestore &&
-          MI->getOperand(1).isFI() &&
-          isCalleeSavedRegister(MI->getOperand(0).getReg(), CSRegs));
-}
-
-void Thumb2RegisterInfo::emitEpilogue(MachineFunction &MF,
-                                      MachineBasicBlock &MBB) const {
-  MachineBasicBlock::iterator MBBI = prior(MBB.end());
-  assert((MBBI->getOpcode() == ARM::tBX_RET ||
-          MBBI->getOpcode() == ARM::tPOP_RET) &&
-         "Can only insert epilog into returning blocks");
-  DebugLoc dl = MBBI->getDebugLoc();
-  MachineFrameInfo *MFI = MF.getFrameInfo();
-  ARMFunctionInfo *AFI = MF.getInfo<ARMFunctionInfo>();
-  unsigned VARegSaveSize = AFI->getVarArgsRegSaveSize();
-  int NumBytes = (int)MFI->getStackSize();
-
-  if (!AFI->hasStackFrame()) {
-    if (NumBytes != 0)
-      emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
-  } else {
-    // Unwind MBBI to point to first LDR / FLDD.
-    const unsigned *CSRegs = getCalleeSavedRegs();
-    if (MBBI != MBB.begin()) {
-      do
-        --MBBI;
-      while (MBBI != MBB.begin() && isCSRestore(MBBI, CSRegs));
-      if (!isCSRestore(MBBI, CSRegs))
-        ++MBBI;
-    }
-
-    // Move SP to start of FP callee save spill area.
-    NumBytes -= (AFI->getGPRCalleeSavedArea1Size() +
-                 AFI->getGPRCalleeSavedArea2Size() +
-                 AFI->getDPRCalleeSavedAreaSize());
-
-    if (hasFP(MF)) {
-      NumBytes = AFI->getFramePtrSpillOffset() - NumBytes;
-      // Reset SP based on frame pointer only if the stack frame extends beyond
-      // frame pointer stack slot or target is ELF and the function has FP.
-      if (NumBytes)
-        emitThumbRegPlusImmediate(MBB, MBBI, ARM::SP, FramePtr, -NumBytes,
-                                  TII, *this, dl);
-      else
-        BuildMI(MBB, MBBI, dl, TII.get(ARM::tMOVlor2hir), ARM::SP)
-          .addReg(FramePtr);
-    } else {
-      if (MBBI->getOpcode() == ARM::tBX_RET &&
-          &MBB.front() != MBBI &&
-          prior(MBBI)->getOpcode() == ARM::tPOP) {
-        MachineBasicBlock::iterator PMBBI = prior(MBBI);
-        emitSPUpdate(MBB, PMBBI, TII, dl, *this, NumBytes);
-      } else
-        emitSPUpdate(MBB, MBBI, TII, dl, *this, NumBytes);
-    }
-  }
-
-  if (VARegSaveSize) {
-    // Epilogue for vararg functions: pop LR to R3 and branch off it.
-    // FIXME: Verify this is still ok when R3 is no longer being reserved.
-    BuildMI(MBB, MBBI, dl, TII.get(ARM::tPOP)).addReg(ARM::R3);
-
-    emitSPUpdate(MBB, MBBI, TII, dl, *this, VARegSaveSize);
-
-    BuildMI(MBB, MBBI, dl, TII.get(ARM::tBX_RET_vararg)).addReg(ARM::R3);
-    MBB.erase(MBBI);
-  }
-}