On Thu, 27 Jun 2024, Richard Biener wrote:
> The following makes sure that for a SLP reductions all lanes have
> the same STMT_VINFO_REDUC_IDX. Once we move that info and can adjust
> it we can implement swapping. It also makes the existing protection
> against operand swapping trigger for all stmts participating in a
> reduction, not just the final one marked as reduction-def.
This causes quite some fallout but the bugfix for the PR (1/2) regtests
OK so I have pushed only that for now.
Richard.
> * tree-vect-slp.cc (vect_build_slp_tree_1): Compare
> STMT_VINFO_REDUC_IDX.
> (vect_build_slp_tree_2): Prevent operand swapping for
> all stmts participating in a reduction.
> ---
> gcc/tree-vect-slp.cc | 18 ++++++++++++++++--
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
> index cb8604eb611..db006661296 100644
> --- a/gcc/tree-vect-slp.cc
> +++ b/gcc/tree-vect-slp.cc
> @@ -1072,6 +1072,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
> *swap,
> stmt_vec_info first_load = NULL, prev_first_load = NULL;
> bool first_stmt_ldst_p = false, ldst_p = false;
> bool first_stmt_phi_p = false, phi_p = false;
> + int first_reduc_idx = -1;
> bool maybe_soft_fail = false;
> tree soft_fail_nunits_vectype = NULL_TREE;
>
> @@ -1204,6 +1205,7 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
> *swap,
> first_stmt_code = rhs_code;
> first_stmt_ldst_p = ldst_p;
> first_stmt_phi_p = phi_p;
> + first_reduc_idx = STMT_VINFO_REDUC_IDX (stmt_info);
>
> /* Shift arguments should be equal in all the packed stmts for a
> vector shift with scalar shift operand. */
> @@ -1267,6 +1269,19 @@ vect_build_slp_tree_1 (vec_info *vinfo, unsigned char
> *swap,
> }
> else
> {
> + if (first_reduc_idx != STMT_VINFO_REDUC_IDX (stmt_info))
> + {
> + if (dump_enabled_p ())
> + {
> + dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
> + "Build SLP failed: different reduc_idx "
> + "%d instead of %d in %G",
> + STMT_VINFO_REDUC_IDX (stmt_info),
> + first_reduc_idx, stmt);
> + }
> + /* Mismatch. */
> + continue;
> + }
> if (first_stmt_code != rhs_code
> && alt_stmt_code == ERROR_MARK)
> alt_stmt_code = rhs_code;
> @@ -2535,8 +2550,7 @@ out:
> && oprnds_info[1]->first_dt == vect_internal_def
> && is_gimple_assign (stmt_info->stmt)
> /* Swapping operands for reductions breaks assumptions later on. */
> - && STMT_VINFO_DEF_TYPE (stmt_info) != vect_reduction_def
> - && STMT_VINFO_DEF_TYPE (stmt_info) != vect_double_reduction_def)
> + && STMT_VINFO_REDUC_IDX (stmt_info) != -1)
> {
> /* See whether we can swap the matching or the non-matching
> stmt operands. */
>
--
Richard Biener <rguent...@suse.de>
SUSE Software Solutions Germany GmbH,
Frankenstrasse 146, 90461 Nuernberg, Germany;
GF: Ivo Totev, Andrew McDonald, Werner Knoblich; (HRB 36809, AG Nuernberg)
