I agree, and I put some effort into this, managing to get something that starts up at -O1 (I think) but not at -O2 (or at -O0 but not at -O1).  I *think* this might be a bug in llvm, because the Cogit is pretty aggressive in its use of alloca.  I should try and make a report for the llvm maintainers.  Either I'll find out I've made a mistake or they'll fix the bug ;)  Biut finding the time is as always the issue :)