Hint Rewrite sem_cast_neutral_int using
(auto;
match goal with H: is_int ?i ?s ?v |- isVint ?v => apply (is_int_is_Vint i s v H) end) : norm.

Lemma sizeof_tuchar: forall {cs: compspecs}, sizeof tuchar = 1%Z.
Hint Rewrite @eval_expr_Etempvar : eval.