Re: Compiling source code with my own flags
On 2010-06-28 21:32 +0200, Sven Joachim wrote:
> On 2010-06-28 21:07 +0200, Tomasz Maluszycki wrote:
> > (for me -O3 is stable... I didn't had any problem with it)
>
> Depends on the program, I think. In general, -O3 produces bigger
> binaries (than -O2) that may or may not run faster. Mozilla even
> builds with -Os by default.
You'd be surprised at the optimisations that GCC misses on i386.
I've seen it needlessly reload registers on every iteration on a
tight loop. Neither -O2 nor -O3 changed that. The only way to make
it generate sane code was -Os.
These days, it's not safe to assume that -O3 produces the fastest
binaries. Always benchmark it against -Os.
--
André Majorel <http://www.teaser.fr/~amajorel/>
bugs.debian.org, your one-stop shop for email addresses.
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