Re: [PATCH 5/7] PHIOPT: Allow MIN/MAX to have up to 2 MIN/MAX expressions for early phiopt

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

On Mon, Apr 24, 2023 at 11:33 PM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> In the early PHIOPT mode, the original minmax_replacement, would
> replace a PHI node with up to 2 min/max expressions in some cases,
> this allows for that too.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

OK.

> gcc/ChangeLog:
>
>         * tree-ssa-phiopt.cc (phiopt_early_allow): Allow for
>         up to 2 min/max expressions in the sequence/match code.
> ---
>  gcc/tree-ssa-phiopt.cc | 16 +++++++++++++++-
>  1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
> index fb2d2c9fc1a..de1896aa91a 100644
> --- a/gcc/tree-ssa-phiopt.cc
> +++ b/gcc/tree-ssa-phiopt.cc
> @@ -542,9 +542,23 @@ phiopt_early_allow (gimple_seq &seq, gimple_match_op &op)
>      return false;
>    tree_code code = (tree_code)op.code;
>
> -  /* For non-empty sequence, only allow one statement.  */
> +  /* For non-empty sequence, only allow one statement
> +     except for MIN/MAX, allow max 2 statements,
> +     each with MIN/MAX.  */
>    if (!gimple_seq_empty_p (seq))
>      {
> +      if (code == MIN_EXPR || code == MAX_EXPR)
> +       {
> +         if (!gimple_seq_singleton_p (seq))
> +           return false;
> +
> +         gimple *stmt = gimple_seq_first_stmt (seq);
> +         /* Only allow assignments.  */
> +         if (!is_gimple_assign (stmt))
> +           return false;
> +         code = gimple_assign_rhs_code (stmt);
> +         return code == MIN_EXPR || code == MAX_EXPR;
> +       }
>        /* Check to make sure op was already a SSA_NAME.  */
>        if (code != SSA_NAME)
>         return false;
> --
> 2.39.1
>