Proof with eauto with wd.
intros.
destruct Hge_wd as (H1 & H2).
unfold symbol_address, Senv.symbol_address in *;
simpl in *.
specialize (H2 id i _ ltac:(reflexivity)).
destruct (find_symbol g id); auto.
eapply valid_val_incr; eauto.
Qed.
Hint Resolve valid_symb : wd.

(* Specifications: *)
Lemma valid_val_cmpu:
forall f ptr c v1 v2,
valid_val f (Val.cmpu ptr c v1 v2).