`reallyUnsafePtrEquality#` should be levity polymorphic
I don't see why we couldn't use reallyUnsafePtrEquality# on types of kind UnliftedRep. Currently, we have to throw in an additional unsafeCoerce to achieve equality comparison of unlifted pointers.
This would allow to subsume sameMutableByteArray# and the requested sameByteArray# (#9192 (closed)) primitives. They are already lowered by the same Cmm MachOp, which is MO_Eq.
Edited by Sebastian Graf