https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67153
--- Comment #10 from ncm at cantrip dot org --- I found this, which at first blush seems like it might be relevant. The hardware complained about here is the same Haswell i7-4770. http://stackoverflow.com/questions/25078285/replacing-a-32-bit-loop-count-variable-with-64-bit-introduces-crazy-performance
