>> 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. Thanks, Grant
