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/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index 804f7ba..4bae160 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -417,7 +417,7 @@
       if (VA.needsCustom()) {
         assert(VA.getLocVT() == MVT::f64 || VA.getLocVT() == MVT::v2i32);
 
-        unsigned VRegHi = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);
+        Register VRegHi = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);
         MF.getRegInfo().addLiveIn(VA.getLocReg(), VRegHi);
         SDValue HiVal = DAG.getCopyFromReg(Chain, dl, VRegHi, MVT::i32);
 
@@ -445,7 +445,7 @@
         InVals.push_back(WholeValue);
         continue;
       }
-      unsigned VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);
+      Register VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);
       MF.getRegInfo().addLiveIn(VA.getLocReg(), VReg);
       SDValue Arg = DAG.getCopyFromReg(Chain, dl, VReg, MVT::i32);
       if (VA.getLocVT() == MVT::f32)
@@ -552,7 +552,7 @@
     std::vector<SDValue> OutChains;
 
     for (; CurArgReg != ArgRegEnd; ++CurArgReg) {
-      unsigned VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);
+      Register VReg = RegInfo.createVirtualRegister(&SP::IntRegsRegClass);
       MF.getRegInfo().addLiveIn(*CurArgReg, VReg);
       SDValue Arg = DAG.getCopyFromReg(DAG.getRoot(), dl, VReg, MVT::i32);