-msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mavx -march=native causes the compiler to emit instructions that are not supported on older CPUs. Omitting these entirely and relying only on x86_64's required SSE support slows down 4D muktiple gradient evaluations by a factor 2. Figure out which of these are critical, and decide how much we need to support older CPUs.
-msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mavx -march=nativecauses the compiler to emit instructions that are not supported on older CPUs. Omitting these entirely and relying only on x86_64's required SSE support slows down 4D muktiple gradient evaluations by a factor 2. Figure out which of these are critical, and decide how much we need to support older CPUs.