In which case does automatic memory allocation occur for the root view of the controller?

Automatic memory management for the root view controller's view occurs when its view is loaded into memory, i.e., upon the first access to the controller's view property.

In iOS, view controllers use lazy loading of views: the view is not created immediately upon controller initialization but only when needed to display the interface.

For example, when setting the root view controller in the app window:

window.rootViewController = myViewController
window.makeKeyAndVisible()

When the system first accesses myViewController.view, the view is loaded and memory is allocated, calling loadView and then viewDidLoad.

Thus, memory is allocated automatically upon the first request to the root view, optimizing resource use.