NSCalendar has a method that does exactly what you want actually!
/*
This API compares the Days of the given dates, reporting them equal if they are in the same Day.
*/
- (BOOL)isDate:(NSDate *)date1 inSameDayAsDate:(NSDate *)date2 NS_AVAILABLE(10_9, 8_0);
So you'd use it like this:
[[NSCalendar currentCalendar] isDate:date1 inSameDayAsDate:date2];
Or in Swift
Calendar.current.isDate(date1, inSameDayAs:date2)