[PATCH] Simplify (view_convert ~a) < 0 to (view_convert a) >= 0 [PR middle-end/100738]

Andrew Pinski pinskia@gmail.com
Tue Jun 1 05:29:11 GMT 2021


On Mon, May 31, 2021 at 10:21 PM Hongtao Liu via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi:
>   This patch is about to simplify (view_convert:type ~a) < 0 to
> (view_convert:type a) >= 0 when type is signed integer. Similar for
> (view_convert:type ~a) >= 0.
>   Bootstrapped and regtested on x86_64-linux-gnu{-m32,}.
>   Ok for the trunk?

Why not just do instead:

/* ((view_convert)~a) is just ~(view_convert)a .  */
(simplify
  (view_convert (bit_not @0))
  (if ((VECTOR_TYPE_P (type) && INTEGRAL_TYPE_P (TREE_TYPE (type)))
        || INTEGRAL_TYPE_P (type))
   (bit_not (view_convert @0))))

And then the other patterns for converting ~a < 0 to a >= 0 should
happen (if they don't add a few) (for wrapping types).

Thanks,
Andrew Pinski

>
> gcc/ChangeLog:
>
>         PR middle-end/100738
>         * match.pd ((view_convert ~a) < 0 --> (view_convert a) >= 0,
>         (view_convert ~a) >= 0 --> (view_convert a) < 0): New GIMPLE
>         simplification.
>
> gcc/testsuite/ChangeLog:
>
>         PR middle-end/100738
>         * g++.target/i386/avx2-pr100738-1.C: New test.
>         * g++.target/i386/sse4_1-pr100738-1.C: New test.
>
> --
> BR,
> Hongtao


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