>>> Now I'm running into "trap invalid opcode" errors on the older >>> systems. Can I disable some of the newer CPU instruction sets on the >>> master laptop when compiling to hopefully generate binaries that will >>> work on the older systems? >> >> Yes. You need to find out CPU_FLAGS_X86 and "-march=" values the >> machines have, and use that in make.conf. Run the commands... >> >> cpuinfo2cpuflags-x86 >> gcc -c -Q -march=native --help=target | grep march= >> >> ...on the target machines. This will tell you what "native" is and >> what CPU_FLAGS_X86 values to use. >> >> https://gcc.gnu.org/onlinedocs/gcc-6.3.0/gcc/x86-Options.html#x86-Options >> lists available "march=" options, and what instruction sets they support. >> E.g. my old core2 desktop shows... >> >> [d531][waltdnes][~] cpuinfo2cpuflags-x86 >> CPU_FLAGS_X86="mmx mmxext sse sse2 sse3 ssse3" >> >> [d531][waltdnes][~] gcc -c -Q -march=native --help=target | grep march= >> -march= core2 >> >> >> Unless the laptops are really old, you can probably get away with... >> CFLAGS="-O2 march=core2 -mfpmath=sse -fopenmp -fomit-frame-pointer -pipe >> -fno-unwind-tables -fno-asynchronous-unwind-tables" >> >> booby trap 1) Unless all machines are Intel "Atom" family, do *NOT* use >> a "march=" that implements the "movbe" instruction. >> >> booby trap 2) If you throw in any AMD-based machines proceed with care. >> >> Can you post the output of... >> gcc -c -Q -march=native --help=target | grep march= >> ...for all the target machines? > > > Let's see how -mtune=native goes and resort to the above if necessary. > It doesn't look too bad though.
emerge -e world has finished and pushed and -mtune=native seems to have solved the issue for now. - Grant
