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From: Richard Biener <richard.guenther@gmail.com>
Date: Thu, 2 Apr 2020 11:21:33 +0200
Message-ID: <CAFiYyc1sx-fYORymvYEhg+T1LKiqg2JKS4AmvzMi8TCLSshzyg@mail.gmail.com>
Subject: Re: [PATCH] Fix PR94401 by considering reverse overrun
To: "Kewen.Lin" <linkw@linux.ibm.com>
Cc: GCC Patches <gcc-patches@gcc.gnu.org>, 
 Segher Boessenkool <segher@kernel.crashing.org>,
 Bill Schmidt <wschmidt@linux.ibm.com>
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On Thu, Apr 2, 2020 at 9:15 AM Kewen.Lin <linkw@linux.ibm.com> wrote:
>
> Hi,
>
> The commit r10-7415 brings scalar type consideration
> to eliminate epilogue peeling for gaps, but it exposed
> one problem that the current handling doesn't consider
> the memory access type VMAT_CONTIGUOUS_REVERSE, for
> which the overrun happens on low address side.  This
> patch is to make the code take care of it by updating
> the offset and construction element order accordingly.
>
> Bootstrapped/regtested on powerpc64le-linux-gnu P8
> and aarch64-linux-gnu.

OK with the formatting changes suggested by Jakub.

Richard.

> BR,
> Kewen
> -----------
> gcc/ChangeLog
>
> 2020-04-02  Kewen Lin  <linkw@gcc.gnu.org>
>
>         PR tree-optimization/94401
>         * tree-vect-loop.c (vectorizable_load): Handle VMAT_CONTIGUOUS_REVERSE
>         access type when loading halves of vector to avoid peeling for gaps.