Re: [PATCH] MATCH: Remove redundant pattern for `(x | y) & ~x`

[Richard Biener <richard.guenther@gmail.com>]

On Mon, Aug 28, 2023 at 5:54 AM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> After r14-2885-gb9237226fdc938, this pattern becomes
> redundant as we match it using bitwise_inverted_equal_p.
>
> There is already a testcase (gcc.dg/nand.c) for this pattern
> and it still passes after the removal.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

OK.

> gcc/ChangeLog:
>
>         PR tree-optimization/111146
>         * match.pd (`(x | y) & ~x`, `(x & y) | ~x`): Remove
>         redundant pattern.
> ---
>  gcc/match.pd | 8 --------
>  1 file changed, 8 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index fa598d5ca2e..0076392c522 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -1556,14 +1556,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>   (bit_ior:c (bit_xor:s @0 @1) (bit_not:s (bit_ior:s @0 @1)))
>   (bit_not (bit_and @0 @1)))
>
> -/* (x | y) & ~x -> y & ~x */
> -/* (x & y) | ~x -> y | ~x */
> -(for bitop (bit_and bit_ior)
> -     rbitop (bit_ior bit_and)
> - (simplify
> -  (bitop:c (rbitop:c @0 @1) (bit_not@2 @0))
> -  (bitop @1 @2)))
> -
>  /* (x & y) ^ (x | y) -> x ^ y */
>  (simplify
>   (bit_xor:c (bit_and @0 @1) (bit_ior @0 @1))
> --
> 2.31.1
>