[RISCV] Convert registers from unsigned to Register

Only in public interfaces that have not yet been converted should there remain
registers with unsigned type.

Differential Revision: https://reviews.llvm.org/D66252

llvm-svn: 369114
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp
index bc45262..082bd33 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.cpp
@@ -17,6 +17,7 @@
 #include "RISCVTargetStreamer.h"
 #include "TargetInfo/RISCVTargetInfo.h"
 #include "llvm/ADT/STLExtras.h"
+#include "llvm/CodeGen/Register.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
@@ -52,7 +53,7 @@
                                        const Triple &TT) {
   MCAsmInfo *MAI = new RISCVMCAsmInfo(TT);
 
-  unsigned SP = MRI.getDwarfRegNum(RISCV::X2, true);
+  Register SP = MRI.getDwarfRegNum(RISCV::X2, true);
   MCCFIInstruction Inst = MCCFIInstruction::createDefCfa(nullptr, SP, 0);
   MAI->addInitialFrameState(Inst);