https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69564
--- Comment #15 from Artem S. Tashkinov <t.artem at mailcity dot com> --- Is this the same bug? https://www.phoronix.com/scan.php?page=article&item=ubuntu-1604-compilers&num=2 In Dense LU Matrix Factorization GCC 5.3.1/6.0 is more than 2 times slower than Clang. G++ options: -O3 -march=native CPU: Xeon E3-1280 v5
