diff --git a/llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp b/llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp
--- a/llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp
+++ b/llvm/lib/Target/AVR/AVRExpandPseudoInsts.cpp
@@ -51,9 +51,9 @@
   const TargetInstrInfo *TII;
 
   /// The register to be used for temporary storage.
-  const unsigned SCRATCH_REGISTER = AVR::R0;
+  const Register SCRATCH_REGISTER = AVR::R0;
   /// The register that will always contain zero.
-  const unsigned ZERO_REGISTER = AVR::R1;
+  const Register ZERO_REGISTER = AVR::R1;
   /// The IO address of the status register.
   const unsigned SREG_ADDR = 0x3f;
 
@@ -66,7 +66,7 @@
   }
 
   MachineInstrBuilder buildMI(Block &MBB, BlockIt MBBI, unsigned Opcode,
-                              unsigned DstReg) {
+                              Register DstReg) {
     return BuildMI(MBB, MBBI, MBBI->getDebugLoc(), TII->get(Opcode), DstReg);
   }
 
@@ -91,7 +91,7 @@
                                 BlockIt MBBI);
 
   /// Scavenges a free GPR8 register for use.
-  unsigned scavengeGPR8(MachineInstr &MI);
+  Register scavengeGPR8(MachineInstr &MI);
 };
 
 char AVRExpandPseudo::ID = 0;
@@ -141,7 +141,7 @@
 bool AVRExpandPseudo::
 expandArith(unsigned OpLo, unsigned OpHi, Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
+  Register SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
   Register DstReg = MI.getOperand(0).getReg();
   Register SrcReg = MI.getOperand(2).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
@@ -174,7 +174,7 @@
 bool AVRExpandPseudo::
 expandLogic(unsigned Op, Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
+  Register SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
   Register DstReg = MI.getOperand(0).getReg();
   Register SrcReg = MI.getOperand(2).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
@@ -221,7 +221,7 @@
 bool AVRExpandPseudo::
 expandLogicImm(unsigned Op, Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned DstLoReg, DstHiReg;
+  Register DstLoReg, DstHiReg;
   Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(1).isKill();
@@ -273,8 +273,8 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::SUBIWRdK>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(3).isDead();
@@ -325,16 +325,16 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::SBCIWRdK>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(3).isDead();
   unsigned Imm = MI.getOperand(2).getImm();
   unsigned Lo8 = Imm & 0xff;
   unsigned Hi8 = (Imm >> 8) & 0xff;
-  OpLo = AVR::SBCIRdK;
-  OpHi = AVR::SBCIRdK;
+  unsigned OpLo = AVR::SBCIRdK;
+  unsigned OpHi = AVR::SBCIRdK;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -388,13 +388,13 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::COMWRd>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool DstIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
-  OpLo = AVR::COMRd;
-  OpHi = AVR::COMRd;
+  unsigned OpLo = AVR::COMRd;
+  unsigned OpHi = AVR::COMRd;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -418,14 +418,14 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::CPWRdRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool DstIsKill = MI.getOperand(0).isKill();
   bool SrcIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
-  OpLo = AVR::CPRdRr;
-  OpHi = AVR::CPCRdRr;
+  unsigned OpLo = AVR::CPRdRr;
+  unsigned OpHi = AVR::CPCRdRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
@@ -451,14 +451,14 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::CPCWRdRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register SrcLoReg, SrcHiReg, DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool DstIsKill = MI.getOperand(0).isKill();
   bool SrcIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
-  OpLo = AVR::CPCRdRr;
-  OpHi = AVR::CPCRdRr;
+  unsigned OpLo = AVR::CPCRdRr;
+  unsigned OpHi = AVR::CPCRdRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
@@ -486,11 +486,11 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LDIWRdK>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
-  OpLo = AVR::LDIRdK;
-  OpHi = AVR::LDIRdK;
+  unsigned OpLo = AVR::LDIRdK;
+  unsigned OpHi = AVR::LDIRdK;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -535,11 +535,11 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LDSWRdK>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
-  OpLo = AVR::LDSRdK;
-  OpHi = AVR::LDSRdK;
+  unsigned OpLo = AVR::LDSRdK;
+  unsigned OpHi = AVR::LDSRdK;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -579,21 +579,21 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LDWRdPtr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned TmpReg = 0; // 0 for no temporary register
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register TmpReg = 0; // 0 for no temporary register
+  Register SrcReg = MI.getOperand(1).getReg();
   bool SrcIsKill = MI.getOperand(1).isKill();
-  OpLo = AVR::LDRdPtr;
-  OpHi = AVR::LDDRdPtrQ;
+  unsigned OpLo = AVR::LDRdPtr;
+  unsigned OpHi = AVR::LDDRdPtrQ;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // Use a temporary register if src and dst registers are the same.
   if (DstReg == SrcReg)
     TmpReg = scavengeGPR8(MI);
 
-  unsigned CurDstLoReg = (DstReg == SrcReg) ? TmpReg : DstLoReg;
-  unsigned CurDstHiReg = (DstReg == SrcReg) ? TmpReg : DstHiReg;
+  Register CurDstLoReg = (DstReg == SrcReg) ? TmpReg : DstLoReg;
+  Register CurDstHiReg = (DstReg == SrcReg) ? TmpReg : DstHiReg;
 
   // Load low byte.
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -628,13 +628,13 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LDWRdPtrPi>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsDead = MI.getOperand(1).isKill();
-  OpLo = AVR::LDRdPtrPi;
-  OpHi = AVR::LDRdPtrPi;
+  unsigned OpLo = AVR::LDRdPtrPi;
+  unsigned OpHi = AVR::LDRdPtrPi;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   assert(DstReg != SrcReg && "SrcReg and DstReg cannot be the same");
@@ -659,13 +659,13 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LDWRdPtrPd>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsDead = MI.getOperand(1).isKill();
-  OpLo = AVR::LDRdPtrPd;
-  OpHi = AVR::LDRdPtrPd;
+  unsigned OpLo = AVR::LDRdPtrPd;
+  unsigned OpHi = AVR::LDRdPtrPd;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   assert(DstReg != SrcReg && "SrcReg and DstReg cannot be the same");
@@ -690,14 +690,14 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LDDWRdPtrQ>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned TmpReg = 0; // 0 for no temporary register
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register TmpReg = 0; // 0 for no temporary register
+  Register SrcReg = MI.getOperand(1).getReg();
   unsigned Imm = MI.getOperand(2).getImm();
   bool SrcIsKill = MI.getOperand(1).isKill();
-  OpLo = AVR::LDDRdPtrQ;
-  OpHi = AVR::LDDRdPtrQ;
+  unsigned OpLo = AVR::LDDRdPtrQ;
+  unsigned OpHi = AVR::LDDRdPtrQ;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // Since we add 1 to the Imm value for the high byte below, and 63 is the highest Imm value
@@ -708,8 +708,8 @@
   if (DstReg == SrcReg)
     TmpReg = scavengeGPR8(MI);
 
-  unsigned CurDstLoReg = (DstReg == SrcReg) ? TmpReg : DstLoReg;
-  unsigned CurDstHiReg = (DstReg == SrcReg) ? TmpReg : DstHiReg;
+  Register CurDstLoReg = (DstReg == SrcReg) ? TmpReg : DstLoReg;
+  Register CurDstHiReg = (DstReg == SrcReg) ? TmpReg : DstHiReg;
 
   // Load low byte.
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -745,21 +745,21 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LPMWRdZ>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned TmpReg = 0; // 0 for no temporary register
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register TmpReg = 0; // 0 for no temporary register
+  Register SrcReg = MI.getOperand(1).getReg();
   bool SrcIsKill = MI.getOperand(1).isKill();
-  OpLo = AVR::LPMRdZPi;
-  OpHi = AVR::LPMRdZ;
+  unsigned OpLo = AVR::LPMRdZPi;
+  unsigned OpHi = AVR::LPMRdZ;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // Use a temporary register if src and dst registers are the same.
   if (DstReg == SrcReg)
     TmpReg = scavengeGPR8(MI);
 
-  unsigned CurDstLoReg = (DstReg == SrcReg) ? TmpReg : DstLoReg;
-  unsigned CurDstHiReg = (DstReg == SrcReg) ? TmpReg : DstHiReg;
+  Register CurDstLoReg = (DstReg == SrcReg) ? TmpReg : DstLoReg;
+  Register CurDstHiReg = (DstReg == SrcReg) ? TmpReg : DstHiReg;
 
   // Load low byte.
   auto MIBLO = buildMI(MBB, MBBI, OpLo)
@@ -862,7 +862,7 @@
   });
 }
 
-unsigned AVRExpandPseudo::scavengeGPR8(MachineInstr &MI) {
+Register AVRExpandPseudo::scavengeGPR8(MachineInstr &MI) {
   MachineBasicBlock &MBB = *MI.getParent();
   RegScavenger RS;
 
@@ -968,11 +968,11 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::STSWKRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register SrcReg = MI.getOperand(1).getReg();
   bool SrcIsKill = MI.getOperand(1).isKill();
-  OpLo = AVR::STSKRr;
-  OpHi = AVR::STSKRr;
+  unsigned OpLo = AVR::STSKRr;
+  unsigned OpHi = AVR::STSKRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   // Write the high byte first in case this address belongs to a special
@@ -1014,12 +1014,12 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::STWPtrRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool SrcIsKill = MI.getOperand(1).isKill();
-  OpLo = AVR::STPtrRr;
-  OpHi = AVR::STDPtrQRr;
+  unsigned OpLo = AVR::STPtrRr;
+  unsigned OpHi = AVR::STDPtrQRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   //:TODO: need to reverse this order like inw and stsw?
@@ -1042,14 +1042,14 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::STWPtrPiRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(2).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(2).getReg();
   unsigned Imm = MI.getOperand(3).getImm();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(2).isKill();
-  OpLo = AVR::STPtrPiRr;
-  OpHi = AVR::STPtrPiRr;
+  unsigned OpLo = AVR::STPtrPiRr;
+  unsigned OpHi = AVR::STPtrPiRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   assert(DstReg != SrcReg && "SrcReg and DstReg cannot be the same");
@@ -1076,14 +1076,14 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::STWPtrPdRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(2).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(2).getReg();
   unsigned Imm = MI.getOperand(3).getImm();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(2).isKill();
-  OpLo = AVR::STPtrPdRr;
-  OpHi = AVR::STPtrPdRr;
+  unsigned OpLo = AVR::STPtrPdRr;
+  unsigned OpHi = AVR::STPtrPdRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   assert(DstReg != SrcReg && "SrcReg and DstReg cannot be the same");
@@ -1110,14 +1110,14 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::STDWPtrQRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(2).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(2).getReg();
   unsigned Imm = MI.getOperand(1).getImm();
   bool DstIsKill = MI.getOperand(0).isKill();
   bool SrcIsKill = MI.getOperand(2).isKill();
-  OpLo = AVR::STDPtrQRr;
-  OpHi = AVR::STDPtrQRr;
+  unsigned OpLo = AVR::STDPtrQRr;
+  unsigned OpHi = AVR::STDPtrQRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   // Since we add 1 to the Imm value for the high byte below, and 63 is the highest Imm value
@@ -1144,12 +1144,12 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::INWRdA>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
+  Register DstLoReg, DstHiReg;
   unsigned Imm = MI.getOperand(1).getImm();
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
-  OpLo = AVR::INRdA;
-  OpHi = AVR::INRdA;
+  unsigned OpLo = AVR::INRdA;
+  unsigned OpHi = AVR::INRdA;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // Since we add 1 to the Imm value for the high byte below, and 63 is the highest Imm value
@@ -1174,12 +1174,12 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::OUTWARr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
+  Register SrcLoReg, SrcHiReg;
   unsigned Imm = MI.getOperand(0).getImm();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool SrcIsKill = MI.getOperand(1).isKill();
-  OpLo = AVR::OUTARr;
-  OpHi = AVR::OUTARr;
+  unsigned OpLo = AVR::OUTARr;
+  unsigned OpHi = AVR::OUTARr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   // Since we add 1 to the Imm value for the high byte below, and 63 is the highest Imm value
@@ -1205,12 +1205,12 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::PUSHWRr>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, SrcLoReg, SrcHiReg;
-  unsigned SrcReg = MI.getOperand(0).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register SrcReg = MI.getOperand(0).getReg();
   bool SrcIsKill = MI.getOperand(0).isKill();
   unsigned Flags = MI.getFlags();
-  OpLo = AVR::PUSHRr;
-  OpHi = AVR::PUSHRr;
+  unsigned OpLo = AVR::PUSHRr;
+  unsigned OpHi = AVR::PUSHRr;
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
 
   // Low part
@@ -1230,11 +1230,11 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::POPWRd>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   unsigned Flags = MI.getFlags();
-  OpLo = AVR::POPRd;
-  OpHi = AVR::POPRd;
+  unsigned OpLo = AVR::POPRd;
+  unsigned OpHi = AVR::POPRd;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   buildMI(MBB, MBBI, OpHi, DstHiReg).setMIFlags(Flags); // High
@@ -1254,7 +1254,7 @@
 
   MachineInstr &MI = *MBBI;
   unsigned OpShift, OpCarry;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   OpShift = AVR::ADDRdRr;
   OpCarry = AVR::ADCRdRr;
@@ -1291,7 +1291,7 @@
 
   MachineInstr &MI = *MBBI;
   unsigned OpShiftOut, OpLoad, OpShiftIn, OpAdd;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   OpShiftOut = AVR::LSRRd;
   OpLoad = AVR::LDIRdK;
@@ -1334,13 +1334,13 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LSLWRd>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool DstIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
-  OpLo = AVR::ADDRdRr; // ADD Rd, Rd <==> LSL Rd
-  OpHi = AVR::ADCRdRr; // ADC Rd, Rd <==> ROL Rd
+  unsigned OpLo = AVR::ADDRdRr; // ADD Rd, Rd <==> LSL Rd
+  unsigned OpHi = AVR::ADCRdRr; // ADC Rd, Rd <==> ROL Rd
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // Low part
@@ -1367,13 +1367,13 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::LSRWRd>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool DstIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
-  OpLo = AVR::RORRd;
-  OpHi = AVR::LSRRd;
+  unsigned OpLo = AVR::RORRd;
+  unsigned OpHi = AVR::LSRRd;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // High part
@@ -1410,13 +1410,13 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::ASRWRd>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool DstIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
-  OpLo = AVR::RORRd;
-  OpHi = AVR::ASRRd;
+  unsigned OpLo = AVR::RORRd;
+  unsigned OpHi = AVR::ASRRd;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // High part
@@ -1440,7 +1440,7 @@
 
 template <> bool AVRExpandPseudo::expand<AVR::SEXT>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned DstLoReg, DstHiReg;
+  Register DstLoReg, DstHiReg;
   // sext R17:R16, R17
   // mov     r16, r17
   // lsl     r17
@@ -1454,8 +1454,8 @@
   // mov     r17, r16
   // lsl     r17
   // sbc     r17, r17
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
@@ -1499,7 +1499,7 @@
 
 template <> bool AVRExpandPseudo::expand<AVR::ZEXT>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned DstLoReg, DstHiReg;
+  Register DstLoReg, DstHiReg;
   // zext R25:R24, R20
   // mov      R24, R20
   // eor      R25, R25
@@ -1508,8 +1508,8 @@
   // zext R25:R24, R25
   // mov      R24, R25
   // eor      R25, R25
-  unsigned DstReg = MI.getOperand(0).getReg();
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register DstReg = MI.getOperand(0).getReg();
+  Register SrcReg = MI.getOperand(1).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   bool SrcIsKill = MI.getOperand(1).isKill();
   bool ImpIsDead = MI.getOperand(2).isDead();
@@ -1536,12 +1536,12 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::SPREAD>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned OpLo, OpHi, DstLoReg, DstHiReg;
-  unsigned DstReg = MI.getOperand(0).getReg();
+  Register DstLoReg, DstHiReg;
+  Register DstReg = MI.getOperand(0).getReg();
   bool DstIsDead = MI.getOperand(0).isDead();
   unsigned Flags = MI.getFlags();
-  OpLo = AVR::INRdA;
-  OpHi = AVR::INRdA;
+  unsigned OpLo = AVR::INRdA;
+  unsigned OpHi = AVR::INRdA;
   TRI->splitReg(DstReg, DstLoReg, DstHiReg);
 
   // Low part
@@ -1563,8 +1563,8 @@
 template <>
 bool AVRExpandPseudo::expand<AVR::SPWRITE>(Block &MBB, BlockIt MBBI) {
   MachineInstr &MI = *MBBI;
-  unsigned SrcLoReg, SrcHiReg;
-  unsigned SrcReg = MI.getOperand(1).getReg();
+  Register SrcLoReg, SrcHiReg;
+  Register SrcReg = MI.getOperand(1).getReg();
   bool SrcIsKill = MI.getOperand(1).isKill();
   unsigned Flags = MI.getFlags();
   TRI->splitReg(SrcReg, SrcLoReg, SrcHiReg);
diff --git a/llvm/lib/Target/AVR/AVRFrameLowering.cpp b/llvm/lib/Target/AVR/AVRFrameLowering.cpp
--- a/llvm/lib/Target/AVR/AVRFrameLowering.cpp
+++ b/llvm/lib/Target/AVR/AVRFrameLowering.cpp
@@ -507,7 +507,7 @@
     MachineBasicBlock::iterator MBBI = EntryMBB.begin();
     DebugLoc DL = EntryMBB.findDebugLoc(MBBI);
 
-    unsigned SPCopy =
+    Register SPCopy =
         MF.getRegInfo().createVirtualRegister(&AVR::DREGSRegClass);
 
     // Create a copy of SP in function entry before any dynallocas are
diff --git a/llvm/lib/Target/AVR/AVRISelDAGToDAG.cpp b/llvm/lib/Target/AVR/AVRISelDAGToDAG.cpp
--- a/llvm/lib/Target/AVR/AVRISelDAGToDAG.cpp
+++ b/llvm/lib/Target/AVR/AVRISelDAGToDAG.cpp
@@ -265,7 +265,7 @@
       if (RI.getRegClass(Reg) != &AVR::PTRDISPREGSRegClass) {
         SDLoc dl(CopyFromRegOp);
 
-        unsigned VReg = RI.createVirtualRegister(&AVR::PTRDISPREGSRegClass);
+        Register VReg = RI.createVirtualRegister(&AVR::PTRDISPREGSRegClass);
 
         SDValue CopyToReg =
             CurDAG->getCopyToReg(CopyFromRegOp, dl, VReg, CopyFromRegOp);
@@ -294,7 +294,7 @@
   // More generic case.
   // Create chain that puts Op into pointer register
   // and return that register.
-  unsigned VReg = RI.createVirtualRegister(&AVR::PTRDISPREGSRegClass);
+  Register VReg = RI.createVirtualRegister(&AVR::PTRDISPREGSRegClass);
 
   SDValue CopyToReg = CurDAG->getCopyToReg(Op, dl, VReg, Op);
   SDValue CopyFromReg =
diff --git a/llvm/lib/Target/AVR/AVRISelLowering.cpp b/llvm/lib/Target/AVR/AVRISelLowering.cpp
--- a/llvm/lib/Target/AVR/AVRISelLowering.cpp
+++ b/llvm/lib/Target/AVR/AVRISelLowering.cpp
@@ -1516,8 +1516,8 @@
   LoopBB->addSuccessor(RemBB);
   LoopBB->addSuccessor(LoopBB);
 
-  unsigned ShiftAmtReg = RI.createVirtualRegister(&AVR::LD8RegClass);
-  unsigned ShiftAmtReg2 = RI.createVirtualRegister(&AVR::LD8RegClass);
+  Register ShiftAmtReg = RI.createVirtualRegister(&AVR::LD8RegClass);
+  Register ShiftAmtReg2 = RI.createVirtualRegister(&AVR::LD8RegClass);
   Register ShiftReg = RI.createVirtualRegister(RC);
   Register ShiftReg2 = RI.createVirtualRegister(RC);
   Register ShiftAmtSrcReg = MI.getOperand(2).getReg();
diff --git a/llvm/lib/Target/AVR/AVRInstrInfo.cpp b/llvm/lib/Target/AVR/AVRInstrInfo.cpp
--- a/llvm/lib/Target/AVR/AVRInstrInfo.cpp
+++ b/llvm/lib/Target/AVR/AVRInstrInfo.cpp
@@ -52,7 +52,7 @@
       BuildMI(MBB, MI, DL, get(AVR::MOVWRdRr), DestReg)
           .addReg(SrcReg, getKillRegState(KillSrc));
     } else {
-      unsigned DestLo, DestHi, SrcLo, SrcHi;
+      Register DestLo, DestHi, SrcLo, SrcHi;
 
       TRI.splitReg(DestReg, DestLo, DestHi);
       TRI.splitReg(SrcReg,  SrcLo,  SrcHi);
diff --git a/llvm/lib/Target/AVR/AVRRegisterInfo.h b/llvm/lib/Target/AVR/AVRRegisterInfo.h
--- a/llvm/lib/Target/AVR/AVRRegisterInfo.h
+++ b/llvm/lib/Target/AVR/AVRRegisterInfo.h
@@ -49,7 +49,7 @@
 
   /// Splits a 16-bit `DREGS` register into the lo/hi register pair.
   /// \param Reg A 16-bit register to split.
-  void splitReg(unsigned Reg, unsigned &LoReg, unsigned &HiReg) const;
+  void splitReg(Register Reg, Register &LoReg, Register &HiReg) const;
 
   bool shouldCoalesce(MachineInstr *MI,
                       const TargetRegisterClass *SrcRC,
diff --git a/llvm/lib/Target/AVR/AVRRegisterInfo.cpp b/llvm/lib/Target/AVR/AVRRegisterInfo.cpp
--- a/llvm/lib/Target/AVR/AVRRegisterInfo.cpp
+++ b/llvm/lib/Target/AVR/AVRRegisterInfo.cpp
@@ -95,7 +95,8 @@
 }
 
 /// Fold a frame offset shared between two add instructions into a single one.
-static void foldFrameOffset(MachineBasicBlock::iterator &II, int &Offset, unsigned DstReg) {
+static void foldFrameOffset(MachineBasicBlock::iterator &II, int &Offset,
+                            Register DstReg) {
   MachineInstr &MI = *II;
   int Opcode = MI.getOpcode();
 
@@ -264,13 +265,12 @@
   return &AVR::PTRDISPREGSRegClass;
 }
 
-void AVRRegisterInfo::splitReg(unsigned Reg,
-                               unsigned &LoReg,
-                               unsigned &HiReg) const {
-    assert(AVR::DREGSRegClass.contains(Reg) && "can only split 16-bit registers");
+void AVRRegisterInfo::splitReg(Register Reg, Register &LoReg,
+                               Register &HiReg) const {
+  assert(AVR::DREGSRegClass.contains(Reg) && "can only split 16-bit registers");
 
-    LoReg = getSubReg(Reg, AVR::sub_lo);
-    HiReg = getSubReg(Reg, AVR::sub_hi);
+  LoReg = getSubReg(Reg, AVR::sub_lo);
+  HiReg = getSubReg(Reg, AVR::sub_hi);
 }
 
 bool AVRRegisterInfo::shouldCoalesce(MachineInstr *MI,