On Fri, Jun 18, 2021 at 4:24 PM Richard Biener
<richard.guent...@gmail.com> wrote:
>
> On Fri, Jun 18, 2021 at 2:23 PM Richard Biener <rguent...@suse.de> wrote:
> >
> > This places two hacks to avoid an old compile-time issue when
> > vectorizing large permuted SLP groups with gaps where we end up
> > emitting loads and IV adjustments for the gap as well and those
> > have quite a high cost until they are eventually cleaned up.
> >
> > The first hack is to fold the auto-inc style IV updates early
> > in the vectorizer rather than in the next forwprop pass which
> > shortens the SSA use-def chains of the used IV.
> >
> > The second hack is to remove the unused loads after we've picked
> > all that we possibly use.
> >
> > Bootstrap / regtest running on x86_64-unknown-linux-gnu.
> >
> > I wonder if this is too gross (and I have to check the one or two
> > bug duplicates), but it should be at least easy to backport ...
>
> Was apparently too simple - the following passes bootstrap and
> regtest.

I've pushed this now after thinking about better solutions.

Richard.

>
> Richard.

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