-ftree-vectorize can't vectorize plus?

[Dorit Nuzman]

"Devang Patel" <devang.patel@gmail.com> wrote on 11/09/2006 07:30:17 PM:

> > Can these type casts (from uchar to schar and back) be cleaned away
> > by some pass before vectorization, or do we need to teach the
vectorizer
> > to ignore such type casts?
>
> This was considered as tree-combiner's responsibility. However, I do not
> know what is the current state and plan of tree-combiner pass.
tree-combiner
> pass, along with other combining activites, will remove unnecessary
> cast (if possible).
>

so the stuff in tree-ssa-forwprop:eliminate_unnecessary_casts in
autovect-branch is supposed to go under this tree-combiner pass as well, or
do you plan to merge it to mainline some time?

I could add this pattern to the vectorizer's idiom-recognition pass - it's
like a tree-combiner I guess, except it's enabled from within the
vectorizer (and looks only for patterns that can help the vectorizer), and
doesn't change anything if the code doesn't end up getting vectorized. I
imagine this should be only a temporary solution, cause this cleanup is
potentially useful regardless of vectorization.

dorit

> -
> Devang