Exactly. Yes you can use restrict. And, you probably will when writing benchmarks. But, this isn't about speeding up benchmarks. This is about speeding up real

Exactly. Yes you can use restrict. And, you probably will when writing benchmarks. But, this isn't about speeding up benchmarks. This is about speeding up real world production code with real world production deadlines. Are you really going to intelligently and correctly apply restrict to every function you write where it could help in your next commercial product? Do you really expect everyone on your team to do the same and never screw up? Then there's the teeming masses of app developers who aren't quite as awesome as you. You don't care about them, but Apple does. Apple knows most of them couldn't restrict their way into a box ;) But, they still churned out a billion apps that are used by billions of users. Doing whatever we can to trick them into speeding up their code will literally save untold lifetimes of cumulative lag for the users.