Linux 5.12's very bad, double ungood day

P.S. I know that in general, it is impossible for a computer program to spot all possible cases where two programs have identical behaviour. I am not suggesting this assistant could have anything like 100% coverage, even for pure refactoring commits. But if it can tick off 80% of them that would still make a reviewer's life easier, and improve my peace of mind as a programmer. (Did that change from a for-loop to a while-loop affect the behaviour? Hmm, I'm not sure... instead of staring at it or working it through with pencil and paper, let's see if the bytecode has changed. If it has changed, the bytecode diff tool will usually point out what I've accidentally altered.)