Fix incorect Register -> MCRegister conversion

getReg returns a Register which may represent a virtual register.

Author: MaskRay

llvm/lib/CodeGen/SelectionDAG/TargetLowering.cpp

@@ -93,7 +93,7 @@ bool TargetLowering::parametersInCSRMatch(const MachineRegisterInfo &MRI,
     SDValue Value = OutVals[I];
     if (Value->getOpcode() != ISD::CopyFromReg)
       return false;
-    MCRegister ArgReg = cast<RegisterSDNode>(Value->getOperand(1))->getReg();
+    Register ArgReg = cast<RegisterSDNode>(Value->getOperand(1))->getReg();
     if (MRI.getLiveInPhysReg(ArgReg) != Reg)
       return false;
   }