Hint Rewrite offset_val_sizeof_hack3 : norm.
Ltac make_Vptr c :=
let H := fresh in assert (isptr c) by auto;
destruct c; try (contradiction H); clear H.

Lemma Zmax0r: forall n, 0 <= n -> Z.max 0 n = n.
Hint Rewrite Zmax0r using (try computable; rep_omega (*Omega0*)) : norm.