Update Eq IntSet and Eq (IntMap a) (#1028)

* Add benchmarks
* Mark the function INLINABLE for IntMap. On benchmarks for IntMap Int
  this reduces the run time by ~22%.
* Remove definitions for (/=). There is no good reason to implement this
  manually.

Author: meooow25

containers-tests/benchmarks/IntMap.hs

@@ -53,6 +53,7 @@ main = do
         , bench "spanAntitone" $ whnf (M.spanAntitone (<key_mid)) m
         , bench "split" $ whnf (M.split key_mid) m
         , bench "splitLookup" $ whnf (M.splitLookup key_mid) m
+        , bench "eq" $ whnf (\m' -> m' == m') m -- worst case, compares everything
         ]
   where
     elems = elems_hits

containers-tests/benchmarks/IntSet.hs

@@ -56,6 +56,7 @@ main = do
         , bench "split:sparse" $ whnf (IS.split elem_sparse_mid) s_sparse
         , bench "splitMember:dense" $ whnf (IS.splitMember elem_mid) s
         , bench "splitMember:sparse" $ whnf (IS.splitMember elem_sparse_mid) s_sparse
+        , bench "eq" $ whnf (\s' -> s' == s') s -- worst case, compares everything
         ]
   where
     bound = 2^12

containers/src/Data/IntMap/Internal.hs

@@ -3433,8 +3433,7 @@ data Distinct = Distinct | Nondistinct
   Eq
 --------------------------------------------------------------------}
 instance Eq a => Eq (IntMap a) where
-  t1 == t2  = equal t1 t2
-  t1 /= t2  = nequal t1 t2
+  (==) = equal
 
 equal :: Eq a => IntMap a -> IntMap a -> Bool
 equal (Bin p1 l1 r1) (Bin p2 l2 r2)
@@ -3443,14 +3442,7 @@ equal (Tip kx x) (Tip ky y)
   = (kx == ky) && (x==y)
 equal Nil Nil = True
 equal _   _   = False
-
-nequal :: Eq a => IntMap a -> IntMap a -> Bool
-nequal (Bin p1 l1 r1) (Bin p2 l2 r2)
-  = (p1 /= p2) || (nequal l1 l2) || (nequal r1 r2)
-nequal (Tip kx x) (Tip ky y)
-  = (kx /= ky) || (x/=y)
-nequal Nil Nil = False
-nequal _   _   = True
+{-# INLINABLE equal #-}
 
 -- | @since 0.5.9
 instance Eq1 IntMap where

containers/src/Data/IntSet/Internal.hs

@@ -1410,8 +1410,7 @@ data Inserted = Inserted !IntSet ![Key]
   Eq
 --------------------------------------------------------------------}
 instance Eq IntSet where
-  t1 == t2  = equal t1 t2
-  t1 /= t2  = nequal t1 t2
+  (==) = equal
 
 equal :: IntSet -> IntSet -> Bool
 equal (Bin p1 l1 r1) (Bin p2 l2 r2)
@@ -1421,14 +1420,6 @@ equal (Tip kx1 bm1) (Tip kx2 bm2)
 equal Nil Nil = True
 equal _   _   = False
 
-nequal :: IntSet -> IntSet -> Bool
-nequal (Bin p1 l1 r1) (Bin p2 l2 r2)
-  = (p1 /= p2) || (nequal l1 l2) || (nequal r1 r2)
-nequal (Tip kx1 bm1) (Tip kx2 bm2)
-  = kx1 /= kx2 || bm1 /= bm2
-nequal Nil Nil = False
-nequal _   _   = True
-
 {--------------------------------------------------------------------
   Ord
 --------------------------------------------------------------------}