gcc is used to build the Sage maths software
http://www.sagemath.org/
There is one fairly large part (Pari)
http://pari.math.u-bordeaux.fr/
where it has been proposed to compile Pari with -O3, rather than the -O1 it is
the case.
It was changed to -O1 after there were issues on a year-old version of Fedora
with one particular gcc version, but the feeling is that one should not use -O1
for everyone.
How safe is it to distribute code for others to build, where you have selected
-O3 for them? I'm a bit concerned that might be a bit aggressive to use as a
default, given it will potentially be compiled by different gcc versions on
different platforms.
I believe -O2 might be a more sensible default, but would welcome the opinions
of others on the matter.
One thing to bear in mind, is that there is a fairly extensive test suite with
the software (Sage has a lot of checks of Pari).
Dave
