https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98544
--- Comment #22 from Martin Reinecke <mar...@mpa-garching.mpg.de> --- Brilliant, thank you very much for tracking this one down! My FFT library now works correctly again with all optimizations enabled, which is a great relief. The scipy maintainers will be happy that they won't need to fiddle with flags depending on gcc versions :)