Could you least give some timestamps? It's nearly two hours. Anyway, while it is possible that some attributes can cause UB if misused, I very much doubt that'

Could you least give some timestamps? It's nearly two hours. Anyway, while it is possible that some attributes can cause UB if misused, I very much doubt that's possible with [[likely]] and [[unlikely]], as they are just hints for the optimizer, and the optimizer is supposed to preserve semantical guarantees.