Performance is of course lower. But it's impossible to put a number on it. Certainly native calls (printf, scanf, fopen, fread) add a lot of overhead. Also when

Performance is of course lower. But it's impossible to put a number on it. Certainly native calls (printf, scanf, fopen, fread) add a lot of overhead. Also whenever the C memory layout has to be used, performance suffers (e.g. complex pointer arithmetic). But the approach is to get the correct translation first, and then - if needed - bottlenecks can be removed manually. This should lead to a better migration/upgrading experience.