The representation of types is still the same (except in a few rare corner cases, notably pointers outside the OCaml heap). The thing that changed was the introduction of domains, groups of threads which can now run in parallel.
Ok, I was under the impression that (to support true parallelism) they changed their garbage collector which could have affected the way they discern pointers and integers. I can understand if they kept int the same for compatibility reasons, but perhaps they now have a 64 bit unboxed type under a different name?
There's a true 64 bit boxed int (int64) and arrays of unboxed 64 bit ints (bigarray), same as before. Pointers vs integers are still distinguished using the bottom bit.
