Re: [fix] PR39300: make PRE not disturb vectorizer

[Sebastian Pop <sebpop at gmail dot com>]

Hi,

On Tue, Jul 21, 2009 at 04:20, Richard
Guenther<richard.guenther@gmail.com> wrote:
> IMHO the performance numbers speak for themselves. ÂCan you
> re-check with the above change (and also throw it onto the C++
> tester once) and add a vectorization testcase as HJ suggests?
>
> Ok with that changes.

Michael, could you also check whether your patch fixes or not the
following PR: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31756
This PR has a reduced Fortran testcase.

Could you also please look at
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=33244
that has again a PRE vs. vectorization problem and some performance
bonus linked to it ;-)

Now a question to Richi:
could you look again to the solution that I proposed for
"DOM and VRP creating harder to optimize code"
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=23821
that looks similar to the approach that Michael took to prevent PRE
to mess up with simple_iv's?
See the patch and your review:
http://gcc.gnu.org/ml/gcc-patches/2008-01/msg00518.html
http://gcc.gnu.org/ml/gcc-patches/2008-01/msg00534.html

Thanks,
Sebastian