Thanks to your help, i could find the problem. And you're absolutely right, > Who knows if not you? That depends on your backend: Maybe absXX2, maybe > movXXcc, maybe jumping around and movXX and negXX2, ... It was absXX2. > Look at .expand dump and track until where it gets wrong. Presumably a > wrong expander, wrong constraints (missing early clobber), wrong peephole, > whatever. wrong expander. Many thanks again. Andreas