We have a bunch of different primops to test pointer equality between various unlifted pointer types (MutableArray#, MutVar#, etc.). Now that we have the necessary type machinery, I believe we should be able to get away with just one:

unliftedPtrEquality#
  :: forall (a :: TYPE 'UnliftedRep).
     a -> a -> Int#

All the rest can then be defined as regular functions in GHC.Exts or some such.