On Mon, Oct 28, 2024 at 12:42 AM Andrew Pinski <quic_apin...@quicinc.com> wrote:
>
> This moves the check for maybe_undef_p in match_simplify_replacement
> slightly earlier before figuring out the true/false arg using arg0/arg1
> instead.
> In most cases this is no difference in compile time; just in the case
> there is an undef in the args there would be a slight compile time
> improvement as there is no reason to figure out which arg corresponds
> to the true/false side of the conditional.
OK.
> Bootstrapped and tested on x86_64-linux-gnu.
>
> gcc/ChangeLog:
>
> * tree-ssa-phiopt.cc (match_simplify_replacement): Move
> check for maybe_undef_p earlier.
>
> Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
> ---
> gcc/tree-ssa-phiopt.cc | 14 +++++++-------
> 1 file changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
> index f8b119ea836..cffafe101a4 100644
> --- a/gcc/tree-ssa-phiopt.cc
> +++ b/gcc/tree-ssa-phiopt.cc
> @@ -943,6 +943,13 @@ match_simplify_replacement (basic_block cond_bb,
> basic_block middle_bb,
> stmt_to_move_alt))
> return false;
>
> + /* Do not make conditional undefs unconditional. */
> + if ((TREE_CODE (arg0) == SSA_NAME
> + && ssa_name_maybe_undef_p (arg0))
> + || (TREE_CODE (arg1) == SSA_NAME
> + && ssa_name_maybe_undef_p (arg1)))
> + return false;
> +
> /* At this point we know we have a GIMPLE_COND with two successors.
> One successor is BB, the other successor is an empty block which
> falls through into BB.
> @@ -982,13 +989,6 @@ match_simplify_replacement (basic_block cond_bb,
> basic_block middle_bb,
> arg_false = arg0;
> }
>
> - /* Do not make conditional undefs unconditional. */
> - if ((TREE_CODE (arg_true) == SSA_NAME
> - && ssa_name_maybe_undef_p (arg_true))
> - || (TREE_CODE (arg_false) == SSA_NAME
> - && ssa_name_maybe_undef_p (arg_false)))
> - return false;
> -
> tree type = TREE_TYPE (gimple_phi_result (phi));
> {
> auto_flow_sensitive s1(stmt_to_move);
> --
> 2.43.0
>
