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Re: Changing the default 32-bit x86 arch for Fedora 12 (#2)



On Wed, Jun 17, 2009 at 02:41:54PM -0400, Bill Nottingham wrote:
> Gregory Maxwell (gmaxwell 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


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