[Bug rtl-optimization/69710] performance issue with SP Linpack with Autovectorization

[doug.gilmore at imgtec dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69710

--- Comment #12 from Doug Gilmore <doug.gilmore at imgtec dot com> ---
> Yes, I proposed some cleanup passess after vectorization but richi
> thinks it's genrally expensive.  So what's implmentation complexity
> of pass_dominator?
One thing we might consider is only enable it when vectorization is
run on architectures where cleanup is needed.

I plan to send an RFC comment for my patch to see what objections
there are to that approach, though beforehand I'd like to investigate
what could be done to the vectorizer so that it doesn't generate code
that contain false dependencies.