https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67153
--- Comment #4 from ncm at cantrip dot org --- Also fails 5.2.1 (Debian 5.2.1--15) 5.2.1 20150808 As noted, the third version of the program, using bitset but not using lambdas, is as slow as the version using unsigned int -- even when built using gcc-4.9. (Recall the int version and the first bitset version run fast when built with gcc-4.9.) Confirmed that on Westmere, compiled -march=native, all versions run about the same speed with all versions of the compiler reported, and this runtime is about the same as the slow Haswell speed despite the very different clock rate.
