On Wed, Jun 17, 2009 at 02:41:54PM -0400, Bill Nottingham wrote:
Gregory Maxwell (gmaxwell(a)gmail.com) said:
> Consider:
>
> -Os on the x86 build?
Back when I tested before, -Os unilaterally made things worse across
Athlon64/C2D/Atom.
Note that GCC 4.4 switches -Os on for unlikely executed basic blocks and/or
unlikely executed functions (of course profile feedback helps here a lot,
but even without it the heuristics gets it right in many cases), so forcing
-Os for all code, even hot, is not a good idea.
On the other side, compiling everything with -O3 is going to bloat code a
lot, just compile with -O3 the hot compilation units or even better just
hot functions.
Jakub