Open Radar

 
Summary:
Adding a failure dependency to a gesture recognizer is about 40x slower in iOS 9 than it was in iOS 8. This caused our app to freeze for 1.3 seconds on an iPad 4 running iOS 9.

Steps to Reproduce:
1) Create a number of gesture recognizers (our app has a dependency graph of 35 gesture recognizers).
2) Add failure dependencies between the gesture recognizers.
3) Run the code on older hardware running iOS 9.

The sample project has code in ViewController.m that prints the total time to set up the dependencies.

Expected Results:
The performance of iOS 8.

Actual Results:
The sample project takes 1.9 seconds to add the dependencies.

Version:
iOS 9.1 - iOS 9.3 Beta 1

Notes:
-[UIGestureRecognizer requireGestureRecognizerToFail:] should be fast given that N gesture recognizers may have up to N^2 dependencies in complex applications. Even better is if +[_UIGestureRecognizerFailureMap buildFailureMapForFailureRequirements:] was invoked lazily instead of during each new failure dependency.

Configuration:
iPad 4

Attachments:
'GestureLatency.zip' was successfully uploaded.