-plusInt, minusInt, timesInt, quotInt, remInt, gcdInt :: Int -> Int -> Int
-plusInt (I# x) (I# y) = I# (x +# y)
-minusInt(I# x) (I# y) = I# (x -# y)
-timesInt(I# x) (I# y) = I# (x *# y)
-quotInt (I# x) (I# y) = I# (quotInt# x y)
-remInt (I# x) (I# y) = I# (remInt# x y)
-gcdInt (I# a) (I# b) = I# (gcdInt# a b)
+plusInt, minusInt, timesInt, quotInt, remInt, divInt, modInt, gcdInt :: Int -> Int -> Int
+(I# x) `plusInt` (I# y) = I# (x +# y)
+(I# x) `minusInt` (I# y) = I# (x -# y)
+(I# x) `timesInt` (I# y) = I# (x *# y)
+(I# x) `quotInt` (I# y) = I# (x `quotInt#` y)
+(I# x) `remInt` (I# y) = I# (x `remInt#` y)
+(I# x) `divInt` (I# y) = I# (x `divInt#` y)
+(I# x) `modInt` (I# y) = I# (x `modInt#` y)
+
+{-# RULES
+"x# +# 0#" forall x#. x# +# 0# = x#
+"0# +# x#" forall x#. 0# +# x# = x#
+"x# -# 0#" forall x#. x# -# 0# = x#
+"x# -# x#" forall x#. x# -# x# = 0#
+"x# *# 0#" forall x#. x# *# 0# = 0#
+"0# *# x#" forall x#. 0# *# x# = 0#
+"x# *# 1#" forall x#. x# *# 1# = x#
+"1# *# x#" forall x#. 1# *# x# = x#
+ #-}
+
+gcdInt (I# a) (I# b) = g a b
+ where g 0# 0# = error "PrelBase.gcdInt: gcd 0 0 is undefined"
+ g 0# _ = I# absB
+ g _ 0# = I# absA
+ g _ _ = I# (gcdInt# absA absB)
+
+ absInt x = if x <# 0# then negateInt# x else x
+
+ absA = absInt a
+ absB = absInt b