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/PowerPC/PPCVSXFMAMutate.cpp b/llvm/lib/Target/PowerPC/PPCVSXFMAMutate.cpp
index aedbf51..5e150be 100644
--- a/llvm/lib/Target/PowerPC/PPCVSXFMAMutate.cpp
+++ b/llvm/lib/Target/PowerPC/PPCVSXFMAMutate.cpp
@@ -126,7 +126,7 @@
         if (!AddendMI->isFullCopy())
           continue;
 
-        unsigned AddendSrcReg = AddendMI->getOperand(1).getReg();
+        Register AddendSrcReg = AddendMI->getOperand(1).getReg();
         if (Register::isVirtualRegister(AddendSrcReg)) {
           if (MRI.getRegClass(AddendMI->getOperand(0).getReg()) !=
               MRI.getRegClass(AddendSrcReg))
@@ -182,12 +182,12 @@
         //   %5 = A-form-op %5, %5, %11;
         // where %5 and %11 are both kills. This case would be skipped
         // otherwise.
-        unsigned OldFMAReg = MI.getOperand(0).getReg();
+        Register OldFMAReg = MI.getOperand(0).getReg();
 
         // Find one of the product operands that is killed by this instruction.
         unsigned KilledProdOp = 0, OtherProdOp = 0;
-        unsigned Reg2 = MI.getOperand(2).getReg();
-        unsigned Reg3 = MI.getOperand(3).getReg();
+        Register Reg2 = MI.getOperand(2).getReg();
+        Register Reg3 = MI.getOperand(3).getReg();
         if (LIS->getInterval(Reg2).Query(FMAIdx).isKill()
             && Reg2 != OldFMAReg) {
           KilledProdOp = 2;
@@ -214,8 +214,8 @@
 
         // Transform: (O2 * O3) + O1 -> (O2 * O1) + O3.
 
-        unsigned KilledProdReg = MI.getOperand(KilledProdOp).getReg();
-        unsigned OtherProdReg = MI.getOperand(OtherProdOp).getReg();
+        Register KilledProdReg = MI.getOperand(KilledProdOp).getReg();
+        Register OtherProdReg = MI.getOperand(OtherProdOp).getReg();
 
         unsigned AddSubReg = AddendMI->getOperand(1).getSubReg();
         unsigned KilledProdSubReg = MI.getOperand(KilledProdOp).getSubReg();