-interesting (VirtualRegI _) = True
-interesting (VirtualRegHi _) = True
-interesting (VirtualRegF _) = True
-interesting (VirtualRegD _) = True
-interesting (RealReg i) = isFastTrue (freeReg i)
+interesting (RegVirtual _) = True
+interesting (RegReal (RealRegSingle i))
+ = isFastTrue (freeReg i)