Add rounded corners to any view using layer mask.

UIView+RoundedCorners.h

#import <UIKit/UIKit.h>

@interface UIView (RoundedCorners)

- (void)setRoundedCorners:(UIRectCorner)corners radius:(CGSize)size;

@end

UIView+RoundedCorners.m

#import "UIView+RoundedCorners.h"
#import <QuartzCore/QuartzCore.h>

@implementation UIView (RoundedCorners)

- (void)setRoundedCorners:(UIRectCorner)corners radius:(CGSize)size {
    UIBezierPath* maskPath = [UIBezierPath bezierPathWithRoundedRect:self.bounds byRoundingCorners:corners cornerRadii:size];
    
    CAShapeLayer* maskLayer = [CAShapeLayer new];
    maskLayer.frame = self.bounds;
    maskLayer.path = maskPath.CGPath;
    
    self.layer.mask = maskLayer;

}

@end