Proof (unop_long_sound Int64.neg).
Definition addl (x y: aval) :=
match x, y with
| L i, L j => L (Int64.add i j)
| Ptr p, L i | L i, Ptr p => Ptr (if Archi.ptr64 then padd p (Ptrofs.of_int64 i) else poffset p)
| Ptr p, _   | _, Ptr p   => Ptr (poffset p)
| Ifptr p, L i | L i, Ifptr p => Ifptr (if Archi.ptr64 then padd p (Ptrofs.of_int64 i) else poffset p)
| Ifptr p, Ifptr q => Ifptr (plub (poffset p) (poffset q))
| Ifptr p, _ | _, Ifptr p => Ifptr (poffset p)
| _, _ => ntop2 x y
end.

Lemma addl_sound:
forall v w x y, vmatch v x -> vmatch w y -> vmatch (Val.addl v w) (addl x y).