[Bug tree-optimization/67323] Use non-unit stride loads by preference when applicable

["michael.collison at linaro dot org" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67323

--- Comment #2 from Michael Collison <michael.collison at linaro dot org> ---
Richard,

Should I create a test case that fails until you resolve this in GCC 6?

On 08/25/2015 02:14 AM, rguenth at gcc dot gnu.org wrote:
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67323
>
> Richard Biener <rguenth at gcc dot gnu.org> changed:
>
>             What    |Removed                     |Added
> ----------------------------------------------------------------------------
>               Status|UNCONFIRMED                 |ASSIGNED
>     Last reconfirmed|                            |2015-08-25
>                   CC|richard.guenther at gmail dot com  |rguenth at gcc dot gnu.org
>           Depends on|                            |66721
>             Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
>       Ever confirmed|0                           |1
>
> --- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
> Confirmed.  We go down the SLP path here because the vectorizer thinks that
> SLP is always cheaper than using interleaving (which generally is true
> if there were not targets which can do the load plus interleave with
> load-lanes ...).
>
> I think this may be a regression as well because I enhanced SLP to apply
> to way more cases.
>
> Note that my plan is to make the vectorizer consider both (well, not really,
> but this bug shows I maybe should try), SLP and non-SLP, and evaluate based
> on costs which route to go.
>
>
> Referenced Bugs:
>
> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66721
> [Bug 66721] [6 regression] gcc.target/i386/pr61403.c FAILs