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