Marc:
I've had a lot of experience now with the new compile options (and I'm not talking about --enable-gcc-opts) and I have to say that they just aren't worth it. You don't know which of them help the most in execution time, and you don't know which cost the most in compile time. (Hell, you don't even know which ones help *at all*; you could be running compiler passes that hurt run-time performance while eating up compile time.)
You ran a genetic algorithm to guess which optimizations to run. That's fine to get an idea of what to try, but it's not sufficient to foist this pain on your users. Even on my Opteron server development is painful.
So pull back to the old
-O1 -fno-math-errno -fschedule-insns2 -fno-trapping-math -fno-strict- aliasing -fwrapv -fomit-frame-pointer
by default; even offer a configure optimization to add - D___OPTIMIZE_SPACE to the compile line. You have a development model that does whole-program compilation by default; it just can't support the default compiler options chosen at configure time.
Brad