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



On Wed, Jun 17, 2009 at 08:56:58PM +0200, drago01 wrote:
> > 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.
> 
> Is this (bloated code) really a problem if the code runs faster?

Of course it is.  You trash caches by rarely used functions.  You don't want
to optimize rarely used code at the expense of code size, only the often used.

	Jakub


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