Definition env_initial_value (e: env) (m: mem) :=
forall id b ty chunk,
e!id = Some(b, ty) -> access_mode ty = By_value chunk -> Mem.load chunk m b 0 = Some Vundef.

Lemma create_undef_temps_inv:
forall vars id v, (create_undef_temps vars)!id = Some v -> v = Vundef /\ In id (var_names vars).