Building generic libraries for SSE2 (P4 & later)

If all your target machines at least have SSE2, then you can use SSE for double precision computations as well. For intel, chips starting with the Pentium 4 had SSE2, and I believe AMD introduced SSE2 with the Opteron processor. Early P4's are 32-bit, and later are 64-bit, so you will need to decide yourself if you want -b 32 or -b 64 for your libraries. Right now, we have introduced architectural defaults only for 32-bits (meaning the 64-bit installs will take much longer). So, to limit the ISA to 32-bit, add these flags to your configure line:
    -b 32 -V 192 -A x86SSE2

R. Clint Whaley 2016-07-28