>> Actually, I tried with march and got the same, dropping march (the default is native) also results the same. I will try with mtune. > > The default should not be native, that compiles code that can only run > on a particular machine (or identical ones). That's a very bad > default. > > Using a more generic instruction set would produce binaries that run > on all hardware, e.g. -march=x86-64 Forgive my ignorance.... That switch caught my eye because its the opposite of -mach=native, and I thought I would add a compile test using it. The problem is, I can't find its documentation. Confer, https://gcc.gnu.org/onlinedocs/gcc/x86-Options.html. I also tried the usual variants like x86_64-Options.html and x86-64-Options.html. Do you know if the option is documented, and what versions of GCC support it? Jeff
