Re: [PATCH] MATCH: add abs support for half float

[Andrew Pinski]

On Sun, Jul 14, 2024 at 1:12 AM Kugan Vivekanandarajah
<kvivekana...@nvidia.com> wrote:
>
> This patch extends abs detection in matched for half float.
>
> Bootstrapped and regression test on aarch64-linux-gnu. Is this OK for trunk?

This is basically this pattern:
```
 /* A >=/> 0 ? A : -A    same as abs (A) */
 (for cmp (ge gt)
  (simplify
   (cnd (cmp @0 zerop) @1 (negate @1))
    (if (!HONOR_SIGNED_ZEROS (TREE_TYPE(@0))
         && !TYPE_UNSIGNED (TREE_TYPE(@0))
         && bitwise_equal_p (@0, @1))
     (if (TYPE_UNSIGNED (type))
      (absu:type @0)
      (abs @0)))))
```

except extended to handle an optional convert. Why didn't you just
extend the above pattern to handle the convert instead? Also I think
you have an issue with unsigned types with the comparison.
Also you should extend the -abs(A) pattern right below it in a similar fashion.

Thanks,
Andrew Pinski


>
> gcc/ChangeLog:
>
> * match.pd: Add pattern to convert (type)A >=/> 0 ? A : -A into abs (A) for 
> half float.
>
> gcc/testsuite/ChangeLog:
>
> * gcc.dg/tree-ssa/absfloat16.c: New test.
>
> Signed-off-by: Kugan Vivekanandarajah <kvivekana...@nvidia.com>
>