[jhc] Performance of lazy-lists

Hi folks! I try to use this awesome compiler and have several questions. 1. I have this program (see atachement): Now, the first solution is faster with both ghc and jhc, but with jhc it runs in something like O(n) instead of the second, which runs in O(1). Why? 2. Are there any special CPP-flags to find out, whether my program is compiled with jhc, if CPP is enabled? I'm using the latest stable version. Thank you very much for this nice compiler!