Swizzling forces the Objective-C environment to clear its caches of its methods. If you do all your swizzling as early as possible in your program, it probably won't have a noticeable effect.
The compiler cannot do much to optimize method calls, because Objective-C allows you to override any method even at runtime (for example, when swizzling). Thus, you have already paid for performance, depending on whether you use it or not.
rob mayoff
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