The Ord instance for unboxed arrays is very inefficient

The Ord instance for unboxed arrays defined in Data.Array.Base results in code that makes lots of heap allocations and is very slow.

For the record, the Ord instance is defined as so in Data.Array.Base:

instance (Ix ix, Ord e, IArray UArray e) => Ord (UArray ix e) where
    compare = cmpUArray

{-# INLINE cmpUArray #-}
cmpUArray :: (IArray UArray e, Ix i, Ord e) => UArray i e -> UArray i e -> Ordering
cmpUArray arr1 arr2 = compare (assocs arr1) (assocs arr2)

The assocs calls don't appear to be deforested away, and hence, when using the Ord functions on unboxed arrays, the performance is bad to the point of making them unusable.

It seems reasonable to me that compare for unboxed arrays could be implemented strictly, in a tight loop, without any heap allocations at all.