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Re: Patch fixing 3.3 bug PR 9745 and PR 10021
- From: Mark Mitchell <mark at codesourcery dot com>
- To: Michael Matz <matz at suse dot de>
- Cc: Franz Sirl <Franz dot Sirl-kernel at lauterbach dot com>, David Edelsohn <dje at watson dot ibm dot com>, Marcus Meissner <meissner at suse dot de>, gcc at gcc dot gnu dot org, wilson at tuliptree dot org, Olaf Hering <olh at suse dot de>
- Date: 02 Jul 2003 11:49:11 -0700
- Subject: Re: Patch fixing 3.3 bug PR 9745 and PR 10021
- References: <Pine.LNX.firstname.lastname@example.org>
On Wed, 2003-07-02 at 11:17, Michael Matz wrote:
> On Wed, 2 Jul 2003, Franz Sirl wrote:
> > compiled correctly, he has to compile with -O1 (this is what Suse does for
> > their _whole_ build system now) or -O2 -fno-strict-aliasing anyway.
> No, in the packages which bite us we used -fno-strict-aliasing or similar.
> And now we have this patch applied to our gcc. If it creates performance
> problems, well, so be it for now. It's really sad, but broken code is
> > And certainly this is slower than half-working aliasing, or? BTW, do you
> > have any hard numbers on how badly performance is affected (compared to
> > 3.2.3 and 3.3)?
> This would be interesting indeed, yes.
I agree with the fact that data would be helpful; benchmarks with and
without Jim's patch would be nice.
Jim's patch is logical, and seems to be driven from a correct reading of
the interfaces in our aliasing code. I am leaning towards installing
that patch for 3.3.1 at this point. Dale's alternative is another
possibility -- as it pushes the failing cases further into the dark
corners, while preserving the current performance.