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 alloc_variables_initial_value:
forall e m vars e' m',
alloc_variables ge e m vars e' m' ->
env_initial_value e m ->
env_initial_value e' m'.