Apply llvm-prefer-register-over-unsigned from clang-tidy to LLVM

Summary:
This clang-tidy check is looking for unsigned integer variables whose initializer
starts with an implicit cast from llvm::Register and changes the type of the
variable to llvm::Register (dropping the llvm:: where possible).

Partial reverts in:
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
X86FixupLEAs.cpp - Some functions return unsigned and arguably should be MCRegister
X86FrameLowering.cpp - Some functions return unsigned and arguably should be MCRegister
HexagonBitSimplify.cpp - Function takes BitTracker::RegisterRef which appears to be unsigned&
MachineVerifier.cpp - Ambiguous operator==() given MCRegister and const Register
PPCFastISel.cpp - No Register::operator-=()
PeepholeOptimizer.cpp - TargetInstrInfo::optimizeLoadInstr() takes an unsigned&
MachineTraceMetrics.cpp - MachineTraceMetrics lacks a suitable constructor

Manual fixups in:
ARMFastISel.cpp - ARMEmitLoad() now takes a Register& instead of unsigned&
HexagonSplitDouble.cpp - Ternary operator was ambiguous between unsigned/Register
HexagonConstExtenders.cpp - Has a local class named Register, used llvm::Register instead of Register.
PPCFastISel.cpp - PPCEmitLoad() now takes a Register& instead of unsigned&

Depends on D65919

Reviewers: arsenm, bogner, craig.topper, RKSimon

Reviewed By: arsenm

Subscribers: RKSimon, craig.topper, lenary, aemerson, wuzish, jholewinski, MatzeB, qcolombet, dschuff, jyknight, dylanmckay, sdardis, nemanjai, jvesely, wdng, nhaehnle, sbc100, jgravelle-google, kristof.beyls, hiraditya, aheejin, kbarton, fedor.sergeev, javed.absar, asb, rbar, johnrusso, simoncook, apazos, sabuasal, niosHD, jrtc27, MaskRay, zzheng, edward-jones, atanasyan, rogfer01, MartinMosbeck, brucehoult, the_o, tpr, PkmX, jocewei, jsji, Petar.Avramovic, asbirlea, Jim, s.egerton, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D65962

llvm-svn: 369041
diff --git a/llvm/lib/CodeGen/GlobalISel/Utils.cpp b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
index 907cb67..be09db1 100644
--- a/llvm/lib/CodeGen/GlobalISel/Utils.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/Utils.cpp
@@ -43,7 +43,7 @@
     const RegisterBankInfo &RBI, MachineInstr &InsertPt,
     const TargetRegisterClass &RegClass, const MachineOperand &RegMO,
     unsigned OpIdx) {
-  unsigned Reg = RegMO.getReg();
+  Register Reg = RegMO.getReg();
   // Assume physical registers are properly constrained.
   assert(Register::isVirtualRegister(Reg) && "PhysReg not implemented");
 
@@ -72,7 +72,7 @@
     MachineRegisterInfo &MRI, const TargetInstrInfo &TII,
     const RegisterBankInfo &RBI, MachineInstr &InsertPt, const MCInstrDesc &II,
     const MachineOperand &RegMO, unsigned OpIdx) {
-  unsigned Reg = RegMO.getReg();
+  Register Reg = RegMO.getReg();
   // Assume physical registers are properly constrained.
   assert(Register::isVirtualRegister(Reg) && "PhysReg not implemented");
 
@@ -128,7 +128,7 @@
     LLVM_DEBUG(dbgs() << "Converting operand: " << MO << '\n');
     assert(MO.isReg() && "Unsupported non-reg operand");
 
-    unsigned Reg = MO.getReg();
+    Register Reg = MO.getReg();
     // Physical registers don't need to be constrained.
     if (Register::isPhysicalRegister(Reg))
       continue;
@@ -168,7 +168,7 @@
     if (!MO.isReg() || !MO.isDef())
       continue;
 
-    unsigned Reg = MO.getReg();
+    Register Reg = MO.getReg();
     if (Register::isPhysicalRegister(Reg) || !MRI.use_nodbg_empty(Reg))
       return false;
   }
@@ -288,7 +288,7 @@
   if (!DstTy.isValid())
     return nullptr;
   while (DefMI->getOpcode() == TargetOpcode::COPY) {
-    unsigned SrcReg = DefMI->getOperand(1).getReg();
+    Register SrcReg = DefMI->getOperand(1).getReg();
     auto SrcTy = MRI.getType(SrcReg);
     if (!SrcTy.isValid() || SrcTy != DstTy)
       break;