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/Target/Hexagon/HexagonOptAddrMode.cpp b/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp
index 547da9f..14f43e1 100644
--- a/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonOptAddrMode.cpp
@@ -162,7 +162,7 @@
   if (!OffsetOp.isImm() || OffsetOp.getImm() > 3)
     return false;
 
-  unsigned OffsetReg = MI.getOperand(2).getReg();
+  Register OffsetReg = MI.getOperand(2).getReg();
   RegisterRef OffsetRR;
   NodeId OffsetRegRD = 0;
   for (NodeAddr<UseNode *> UA : AddAslSN.Addr->members_if(DFG->IsUse, *DFG)) {
@@ -348,7 +348,7 @@
                                         MachineInstr *AddMI,
                                         const NodeList &UNodeList) {
 
-  unsigned AddDefR = AddMI->getOperand(0).getReg();
+  Register AddDefR = AddMI->getOperand(0).getReg();
   for (auto I = UNodeList.rbegin(), E = UNodeList.rend(); I != E; ++I) {
     NodeAddr<UseNode *> UN = *I;
     NodeAddr<StmtNode *> SN = UN.Addr->getOwner(*DFG);
@@ -381,7 +381,7 @@
     // Ex: Rx= add(Rt,#10)
     //     memw(Rx+#0) = Rs
     // will be replaced with =>  memw(Rt+#10) = Rs
-    unsigned BaseReg = AddMI->getOperand(1).getReg();
+    Register BaseReg = AddMI->getOperand(1).getReg();
     if (!isSafeToExtLR(AddSN, AddMI, BaseReg, UNodeList))
       return false;
   }
@@ -411,7 +411,7 @@
                                         MachineInstr *UseMI) {
   const MachineOperand ImmOp = AddMI->getOperand(2);
   const MachineOperand AddRegOp = AddMI->getOperand(1);
-  unsigned newReg = AddRegOp.getReg();
+  Register newReg = AddRegOp.getReg();
   const MCInstrDesc &MID = UseMI->getDesc();
 
   MachineOperand &BaseOp = MID.mayLoad() ? UseMI->getOperand(1)
@@ -724,7 +724,7 @@
     }
 
     short SizeInc = 0;
-    unsigned DefR = MI->getOperand(0).getReg();
+    Register DefR = MI->getOperand(0).getReg();
     InstrEvalMap InstrEvalResult;
 
     // Analyze all uses and calculate increase in size. Perform the optimization