Re: [PATCH v2] tree-optimization/110279- Check for nested FMA chains in reassoc

[Philipp Tomsich <philipp.tomsich@vrull.eu>]

Jakub,

it looks like you did a lot of work on reassoc in the past — could you
have a quick look and comment?

Thanks,
Philipp.


On Tue, 11 Jul 2023 at 04:59, Di Zhao OS <dizhao@os.amperecomputing.com> wrote:
>
> Attached is an updated version of the patch.
>
> Based on Philipp's review, some changes:
>
> 1. Defined new enum fma_state to describe the state of FMA candidates
>    for a list of operands. (Since the tests seems simple after the
>    change, I didn't add predicates on it.)
> 2. Changed return type of convert_mult_to_fma_1 and convert_mult_to_fma
>    to tree, to remove the in/out parameter.
> 3. Added description of return value values of rank_ops_for_fma.
>
> ---
> gcc/ChangeLog:
>
>         * tree-ssa-math-opts.cc (convert_mult_to_fma_1): Added new parameter
>         check_only_p. Changed return type to tree.
>         (struct fma_transformation_info): Moved to header.
>         (class fma_deferring_state): Moved to header.
>         (convert_mult_to_fma): Added new parameter check_only_p. Changed
>         return type to tree.
>         * tree-ssa-math-opts.h (struct fma_transformation_info): Moved from .cc.
>         (class fma_deferring_state): Moved from .cc.
>         (convert_mult_to_fma): Add function decl.
>         * tree-ssa-reassoc.cc (enum fma_state): Defined new enum to describe
>         the state of FMA candidates for a list of operands.
>         (rewrite_expr_tree_parallel): Changed boolean parameter to enum type.
>         (rank_ops_for_fma): Return enum fma_state.
>         (reassociate_bb): Avoid rewriting to parallel if nested FMAs are found.
>
> Thanks,
> Di Zhao
>
>