-isPtrGlobalReg :: GlobalReg -> Bool
-isPtrGlobalReg (VanillaReg n) = True
-isPtrGlobalReg Sp = True
-isPtrGlobalReg Hp = True
-isPtrGlobalReg HpLim = True
-isPtrGlobalReg SpLim = True
-isPtrGlobalReg _ = False
+-- True if (pprAsPtrReg reg) will give an expression with type StgPtr
+isPtrReg :: CmmReg -> Bool
+isPtrReg (CmmLocal _) = False
+isPtrReg (CmmGlobal (VanillaReg n)) = True -- if we print via pprAsPtrReg
+isPtrReg (CmmGlobal reg) = isFixedPtrGlobalReg reg
+
+-- True if this global reg has type StgPtr
+isFixedPtrGlobalReg :: GlobalReg -> Bool
+isFixedPtrGlobalReg Sp = True
+isFixedPtrGlobalReg Hp = True
+isFixedPtrGlobalReg HpLim = True
+isFixedPtrGlobalReg SpLim = True
+isFixedPtrGlobalReg _ = False