Re: [PATCH 1/2] Move `~X & X` and `~X | X` over to use bitwise_inverted_equal_p

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

On Mon, Jul 31, 2023 at 7:47 PM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> This is a simple patch to move these 2 patterns over to use
> bitwise_inverted_equal_p. It also allows us to remove 2 other patterns
> which were used on comparisons as they are now handled by
> the original pattern.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

OK.

> gcc/ChangeLog:
>
>         * match.pd (`~X & X`, `~X | X`): Move over to
>         use bitwise_inverted_equal_p, removing :c as bitwise_inverted_equal_p
>         handles that already.
>         Remove range test simplifications to true/false as they
>         are now handled by these patterns.
> ---
>  gcc/match.pd | 28 ++++++----------------------
>  1 file changed, 6 insertions(+), 22 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index 74f0a84f31d..7d030262698 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -1157,8 +1157,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>
>  /* Simplify ~X & X as zero.  */
>  (simplify
> - (bit_and:c (convert? @0) (convert? (bit_not @0)))
> -  { build_zero_cst (type); })
> + (bit_and (convert? @0) (convert? @1))
> + (if (bitwise_inverted_equal_p (@0, @1))
> +  { build_zero_cst (type); }))
>
>  /* PR71636: Transform x & ((1U << b) - 1) -> x & ~(~0U << b);  */
>  (simplify
> @@ -1395,8 +1396,9 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>  /* ~x ^ x -> -1 */
>  (for op (bit_ior bit_xor)
>   (simplify
> -  (op:c (convert? @0) (convert? (bit_not @0)))
> -  (convert { build_all_ones_cst (TREE_TYPE (@0)); })))
> +  (op (convert? @0) (convert? @1))
> +  (if (bitwise_inverted_equal_p (@0, @1))
> +   (convert { build_all_ones_cst (TREE_TYPE (@0)); }))))
>
>  /* x ^ x -> 0 */
>  (simplify
> @@ -5994,24 +5996,6 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>   (bit_and:c (ordered @0 @0) (ordered:c@2 @0 @1))
>   @2)
>
> -/* Simple range test simplifications.  */
> -/* A < B || A >= B -> true.  */
> -(for test1 (lt le le le ne ge)
> -     test2 (ge gt ge ne eq ne)
> - (simplify
> -  (bit_ior:c (test1 @0 @1) (test2 @0 @1))
> -  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
> -       || VECTOR_INTEGER_TYPE_P (TREE_TYPE (@0)))
> -   { constant_boolean_node (true, type); })))
> -/* A < B && A >= B -> false.  */
> -(for test1 (lt lt lt le ne eq)
> -     test2 (ge gt eq gt eq gt)
> - (simplify
> -  (bit_and:c (test1 @0 @1) (test2 @0 @1))
> -  (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
> -       || VECTOR_INTEGER_TYPE_P (TREE_TYPE (@0)))
> -   { constant_boolean_node (false, type); })))
> -
>  /* A & (2**N - 1) <= 2**K - 1 -> A & (2**N - 2**K) == 0
>     A & (2**N - 1) >  2**K - 1 -> A & (2**N - 2**K) != 0
>
> --
> 2.31.1
>