In mixing bowl stir half of the ice cream until of spreading consistency; spread evenly in pie crust. Top with half of the cherry pie filling. Freeze until filling is partially frozen, about 45 minutes. Stir remaining ice cream to spreading consistency; spread over partially frozen pie filling in crust. Freeze until firm, at least 3 hours. Just before serving, top with remaining pie filling. Garnish with whipped topping if desired.