(** Builtin arguments and results *)

Lemma can_eval_builtin_arg:
forall sp e m e' m' P,
magree m m' P ->
forall a v,
eval_builtin_arg ge (fun r => e#r) (Vptr sp Ptrofs.zero) m a v ->
exists v', eval_builtin_arg tge (fun r => e'#r) (Vptr sp Ptrofs.zero) m' a v'.