let is_rw_zone (rd_zone_opt, wr_zone_opt) ki =
let rd_zone, wr_zone = get_rw_zone ki in
let inter_zone zone_opt zone =
match zone_opt with
| None -> zone_opt
| Some zone_requested ->
if Locations.Zone.intersects zone_requested zone
then let inter = Locations.Zone.narrow zone_requested zone
in Some inter
else None
in inter_zone rd_zone_opt rd_zone, inter_zone wr_zone_opt wr_zone