在swift中比较两个日期时出现问题

let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let date = dateFormatter.date(from: dateString)

let calendar = Calendar.current
let gmtTimeZone = TimeZone(identifier: "GMT")
let gmtDate = calendar.date(bySettingHour: 0, minute: 0, second: 0, of: date, matchingPolicy: .nextTime, repeatedTimePolicy: .first, direction: .backward)

if date1 < date2 {
    print("date1 is earlier than date2")
} else if date1 > date2 {
    print("date1 is later than date2")
} else {
    print("date1 and date2 are the same")
}