Is there something that can complete this analogy:
(=) is to (==) as Pervasives.compare is to ___?

That is, is there a polymorphic total ordering with respect to *physical*
entities, rather than to their structure?

I'm afraid of getting into trouble with Obj.magic, but what would this do:
let f (x:'a) (y:'a) = compare (Obj.magic x) (Obj.magic y)
? Or would annotations make any difference:
let f (x:'a) (y:'a) = compare (Obj.magic x : int) (Obj.magic y : int)

-Elnatan