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/DetectDeadLanes.cpp b/llvm/lib/CodeGen/DetectDeadLanes.cpp
index 31dea09..6d5306c 100644
--- a/llvm/lib/CodeGen/DetectDeadLanes.cpp
+++ b/llvm/lib/CodeGen/DetectDeadLanes.cpp
@@ -154,7 +154,7 @@
                         const TargetRegisterClass *DstRC,
                         const MachineOperand &MO) {
   assert(lowersToCopies(MI));
-  unsigned SrcReg = MO.getReg();
+  Register SrcReg = MO.getReg();
   const TargetRegisterClass *SrcRC = MRI.getRegClass(SrcReg);
   if (DstRC == SrcRC)
     return false;
@@ -194,7 +194,7 @@
                                             LaneBitmask UsedLanes) {
   if (!MO.readsReg())
     return;
-  unsigned MOReg = MO.getReg();
+  Register MOReg = MO.getReg();
   if (!Register::isVirtualRegister(MOReg))
     return;
 
@@ -250,7 +250,7 @@
       return MO2UsedLanes;
 
     const MachineOperand &Def = MI.getOperand(0);
-    unsigned DefReg = Def.getReg();
+    Register DefReg = Def.getReg();
     const TargetRegisterClass *RC = MRI->getRegClass(DefReg);
     LaneBitmask MO1UsedLanes;
     if (RC->CoveredBySubRegs)
@@ -285,7 +285,7 @@
   if (MI.getOpcode() == TargetOpcode::PATCHPOINT)
     return;
   const MachineOperand &Def = *MI.defs().begin();
-  unsigned DefReg = Def.getReg();
+  Register DefReg = Def.getReg();
   if (!Register::isVirtualRegister(DefReg))
     return;
   unsigned DefRegIdx = Register::virtReg2Index(DefReg);
@@ -377,7 +377,7 @@
     for (const MachineOperand &MO : DefMI.uses()) {
       if (!MO.isReg() || !MO.readsReg())
         continue;
-      unsigned MOReg = MO.getReg();
+      Register MOReg = MO.getReg();
       if (!MOReg)
         continue;
 
@@ -428,7 +428,7 @@
     if (lowersToCopies(UseMI)) {
       assert(UseMI.getDesc().getNumDefs() == 1);
       const MachineOperand &Def = *UseMI.defs().begin();
-      unsigned DefReg = Def.getReg();
+      Register DefReg = Def.getReg();
       // The used lanes of COPY-like instruction operands are determined by the
       // following dataflow analysis.
       if (Register::isVirtualRegister(DefReg)) {
@@ -470,7 +470,7 @@
   if (!lowersToCopies(MI))
     return false;
   const MachineOperand &Def = MI.getOperand(0);
-  unsigned DefReg = Def.getReg();
+  Register DefReg = Def.getReg();
   if (!Register::isVirtualRegister(DefReg))
     return false;
   unsigned DefRegIdx = Register::virtReg2Index(DefReg);
@@ -482,7 +482,7 @@
   if (UsedLanes.any())
     return false;
 
-  unsigned MOReg = MO.getReg();
+  Register MOReg = MO.getReg();
   if (Register::isVirtualRegister(MOReg)) {
     const TargetRegisterClass *DstRC = MRI->getRegClass(DefReg);
     *CrossCopy = isCrossCopy(*MRI, MI, DstRC, MO);
@@ -536,7 +536,7 @@
       for (MachineOperand &MO : MI.operands()) {
         if (!MO.isReg())
           continue;
-        unsigned Reg = MO.getReg();
+        Register Reg = MO.getReg();
         if (!Register::isVirtualRegister(Reg))
           continue;
         unsigned RegIdx = Register::virtReg2Index(Reg);