LivePhysRegs/IfConversion: Change some types from unsigned to MCPhysReg; NFC

Change the type in a couple of lists and sets that only store physical
registers from unsigned to MCPhysRegs. The later is only 16bits and
saves us a bit of memory.

llvm-svn: 346254
diff --git a/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp b/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
index a259824..2f3e18c 100644
--- a/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
+++ b/llvm/lib/Target/Hexagon/HexagonFrameLowering.cpp
@@ -1708,7 +1708,7 @@
   // register that is entirely undefined.
   LivePhysRegs LPR(HRI);
   LPR.addLiveIns(B);
-  SmallVector<std::pair<unsigned, const MachineOperand*>,2> Clobbers;
+  SmallVector<std::pair<MCPhysReg, const MachineOperand*>,2> Clobbers;
   for (auto R = B.begin(); R != It; ++R) {
     Clobbers.clear();
     LPR.stepForward(*R, Clobbers);