Re: GCC 4.2.0 Status Report (2007-05-11)

["Richard Guenther" <richard dot guenther at gmail dot com>]

On 5/14/07, Serge Belyshev <belyshev@depni.sinp.msu.ru> wrote:
> "Richard Guenther" <richard.guenther@gmail.com> writes:
>
> > It was a patch to enable more optimization.  Reverting it should be as safe
> > or unsafe as exchanging forwprop and dce passes.  And I have no idea
> > as how to quantify safeness of either ;)
> >
> > I'd say we better analyze what goes wrong (as the problem is possibly
> > latent on the mainline) and fix it properly.  If we paper over it we will not
> > fix it at all.
> >
>
> I vote for reverting that change (r111639) on the branch before release.
> We would gain nothing by having bug 30252, however latent,
> uncovered in a released compiler.

The patch only changes the heuristic where we create SFTs for.  The bug is in
handling aliasing with SFTs.  So you'll fix this particluar case --
but I have no idea
on what other testcases you re-expose the bug.  So I'd rather stay with a few
now known cases than shipping with other unknown ones (it maybe glibc which
we miscompile after reverting the change).

Richard.