> -----Original Message-----
> From: Richard Biener <[email protected]>
> Sent: 08 July 2026 13:33
> To: [email protected]
> Cc: Tamar Christina <[email protected]>
> Subject: [PATCH] Remove group_size argument from vect_built_slp_tree* APIs
>
> The group_size argument is redundant with the stmt vector length.
>
> Bootstrap and regtest running on x86_64-unknown-linux-gnu.
>
> This is because there's confusion about what group_size is,
> the number of scalar lanes or the number of statements. With
> statements becoming possibly vector stmts how did you handle
> group_size? If the argument becomes useful there we should
> probably rename it?
>
Thanks I think it's better to indeed remove it, since I was trying to figure out
how to deal with SLP build for VLA vector statements and group_size was
definitely an issue.
So LGTM!
Thanks,
Tamar
> * tree-vect-slp.cc (vect_build_slp_tree_1): Remove group_size
> argument and adjust.
> (vect_build_slp_tree_2): Likewise.
> (vect_build_slp_tree): Likewise.
> (optimize_load_redistribution_1): Likewise.
> (vect_build_slp_instance): Likewise.
> (vect_analyze_slp_reduc_chain): Likewise.
> (vect_analyze_slp_reduction): Likewise.
> (vect_analyze_slp_reduction_group): Likewise.
> (vect_analyze_slp_instance): Likewise.
> (vect_lower_load_permutations): Likewise.
> ---
> gcc/tree-vect-slp.cc | 41 +++++++++++++++++++++--------------------
> 1 file changed, 21 insertions(+), 20 deletions(-)
>
> diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
> index 0266e75888c..ff11b392305 100644
> --- a/gcc/tree-vect-slp.cc
> +++ b/gcc/tree-vect-slp.cc
> @@ -1147,10 +1147,11 @@ vect_record_max_nunits (vec_info *vinfo,
> stmt_vec_info stmt_info,
>
> static bool
> vect_build_slp_tree_1 (vec_info *vinfo, unsigned char *swap,
> - vec<stmt_vec_info> stmts, unsigned int group_size,
> + vec<stmt_vec_info> stmts,
> poly_uint64 *max_nunits, bool *matches,
> bool *two_operators, tree *node_vectype)
> {
> + unsigned int group_size = stmts.length ();
> unsigned int i;
> stmt_vec_info first_stmt_info = stmts[0];
> code_helper first_stmt_code = ERROR_MARK;
> @@ -1881,18 +1882,19 @@ static unsigned
> least_upthread_swappable_op_distance = -1U;
>
> static slp_tree
> vect_build_slp_tree_2 (vec_info *vinfo, slp_tree node,
> - vec<stmt_vec_info> stmts, unsigned int group_size,
> + vec<stmt_vec_info> stmts,
> poly_uint64 *max_nunits,
> bool *matches, unsigned *limit, unsigned *tree_size,
> scalar_stmts_to_slp_tree_map_t *bst_map);
>
> static slp_tree
> vect_build_slp_tree (vec_info *vinfo,
> - vec<stmt_vec_info> stmts, unsigned int group_size,
> + vec<stmt_vec_info> stmts,
> poly_uint64 *max_nunits,
> bool *matches, unsigned *limit, unsigned *tree_size,
> scalar_stmts_to_slp_tree_map_t *bst_map)
> {
> + unsigned int group_size = stmts.length ();
> if (slp_tree *leader = bst_map->get (stmts))
> {
> if (dump_enabled_p ())
> @@ -1937,7 +1939,7 @@ vect_build_slp_tree (vec_info *vinfo,
> "starting SLP discovery for node %p\n", (void *) res);
>
> poly_uint64 this_max_nunits = 1;
> - slp_tree res_ = vect_build_slp_tree_2 (vinfo, res, stmts, group_size,
> + slp_tree res_ = vect_build_slp_tree_2 (vinfo, res, stmts,
> &this_max_nunits,
> matches, limit, tree_size, bst_map);
> if (!res_)
> @@ -2025,11 +2027,12 @@ vect_slp_build_two_operator_nodes (slp_tree
> perm, tree vectype,
>
> static slp_tree
> vect_build_slp_tree_2 (vec_info *vinfo, slp_tree node,
> - vec<stmt_vec_info> stmts, unsigned int group_size,
> + vec<stmt_vec_info> stmts,
> poly_uint64 *max_nunits,
> bool *matches, unsigned *limit, unsigned *tree_size,
> scalar_stmts_to_slp_tree_map_t *bst_map)
> {
> + unsigned int group_size = stmts.length ();
> unsigned nops, i, this_tree_size = 0;
> poly_uint64 this_max_nunits = *max_nunits;
>
> @@ -2108,7 +2111,7 @@ vect_build_slp_tree_2 (vec_info *vinfo, slp_tree
> node,
> bool two_operators = false;
> unsigned char *swap = XALLOCAVEC (unsigned char, group_size);
> tree vectype = NULL_TREE;
> - if (!vect_build_slp_tree_1 (vinfo, swap, stmts, group_size,
> + if (!vect_build_slp_tree_1 (vinfo, swap, stmts,
> &this_max_nunits, matches, &two_operators,
> &vectype))
> return NULL;
> @@ -2205,7 +2208,7 @@ vect_build_slp_tree_2 (vec_info *vinfo, slp_tree
> node,
> }
> bool *matches2 = XALLOCAVEC (bool, dr_group_size);
> slp_tree unperm_load
> - = vect_build_slp_tree (vinfo, stmts2, dr_group_size,
> + = vect_build_slp_tree (vinfo, stmts2,
> &this_max_nunits, matches2, limit,
> &this_tree_size, bst_map);
> /* When we are able to do the full masked load emit that
> @@ -2509,7 +2512,7 @@ vect_build_slp_tree_2 (vec_info *vinfo, slp_tree
> node,
> else
> op_stmts.quick_push (NULL);
> child = vect_build_slp_tree (vinfo, op_stmts,
> - group_size,
> &this_max_nunits,
> + &this_max_nunits,
> matches, limit,
> &this_tree_size, bst_map);
> /* ??? We're likely getting too many fatal mismatches
> @@ -2947,7 +2950,7 @@ out:
> vec<stmt_vec_info> def_stmts2;
> def_stmts2.create (1);
> def_stmts2.quick_push (oprnd_info->def_stmts[0]);
> - child = vect_build_slp_tree (vinfo, def_stmts2, 1,
> + child = vect_build_slp_tree (vinfo, def_stmts2,
> &this_max_nunits,
> matches, limit,
> &this_tree_size, bst_map);
> @@ -3021,7 +3024,7 @@ out:
> else if (least_upthread_swappable_op_distance != -1U)
> least_upthread_swappable_op_distance++;
> child = vect_build_slp_tree (vinfo, oprnd_info->def_stmts,
> - group_size, &this_max_nunits,
> + &this_max_nunits,
> matches, limit,
> &this_tree_size, bst_map);
> least_upthread_swappable_op_distance = old_swap_distance;
> @@ -3083,7 +3086,7 @@ out:
> /* And try again with scratch 'matches' ... */
> bool *tem = XALLOCAVEC (bool, group_size);
> if ((child = vect_build_slp_tree (vinfo, oprnd_info->def_stmts,
> - group_size, &this_max_nunits,
> + &this_max_nunits,
> tem, limit,
> &this_tree_size, bst_map)) != NULL)
> {
> @@ -3807,7 +3810,7 @@ optimize_load_redistribution_1
> (scalar_stmts_to_slp_tree_map_t *bst_map,
> bool *matches = XALLOCAVEC (bool, group_size);
> poly_uint64 max_nunits = 1;
> unsigned tree_size = 0, limit = 1;
> - node = vect_build_slp_tree (vinfo, stmts, group_size, &max_nunits,
> + node = vect_build_slp_tree (vinfo, stmts, &max_nunits,
> matches, &limit, &tree_size, bst_map);
> if (!node)
> stmts.release ();
> @@ -4236,7 +4239,7 @@ vect_build_slp_instance (vec_info *vinfo,
> matches[1] = false;
> }
> else
> - node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
> + node = vect_build_slp_tree (vinfo, scalar_stmts,
> &max_nunits, matches, limit,
> &tree_size, bst_map);
> if (node != NULL)
> @@ -4498,7 +4501,7 @@ vect_analyze_slp_reduc_chain (loop_vec_info
> vinfo,
> bool *matches = XALLOCAVEC (bool, group_size);
> poly_uint64 max_nunits = 1;
> unsigned tree_size = 0;
> - slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
> + slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts,
> &max_nunits, matches, limit,
> &tree_size, bst_map);
> if (!node)
> @@ -4646,7 +4649,7 @@ vect_analyze_slp_reduc_chain (loop_vec_info
> vinfo,
> for (unsigned i = 0; i < scalar_stmts.length (); ++i)
> REDUC_GROUP_FIRST_ELEMENT (scalar_stmts[i]) = scalar_stmts[0];
>
> - slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
> + slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts,
> &max_nunits, matches, limit,
> &tree_size, bst_map);
>
> @@ -4790,7 +4793,7 @@ vect_analyze_slp_reduction (loop_vec_info vinfo,
> poly_uint64 max_nunits = 1;
> unsigned tree_size = 0;
>
> - slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
> + slp_tree node = vect_build_slp_tree (vinfo, scalar_stmts,
> &max_nunits, matches, limit,
> &tree_size, bst_map);
> if (node != NULL)
> @@ -4862,7 +4865,6 @@ vect_analyze_slp_reduction_group (loop_vec_info
> loop_vinfo,
> poly_uint64 max_nunits = 1;
> unsigned tree_size = 0;
> slp_tree node = vect_build_slp_tree (loop_vinfo, scalar_stmts,
> - group_size,
> &max_nunits, matches, limit,
> &tree_size, bst_map);
> if (!node)
> @@ -5089,7 +5091,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
> matches[1] = false;
> }
> else
> - node = vect_build_slp_tree (vinfo, scalar_stmts, group_size,
> + node = vect_build_slp_tree (vinfo, scalar_stmts,
> &max_nunits, matches, limit,
> &tree_size, bst_map);
> if (node != NULL)
> @@ -5278,7 +5280,7 @@ vect_analyze_slp_instance (vec_info *vinfo,
> for (unsigned j = start; j < end; ++j)
> substmts.quick_push (scalar_stmts[j]);
> max_nunits = 1;
> - node = vect_build_slp_tree (vinfo, substmts, end - start,
> + node = vect_build_slp_tree (vinfo, substmts,
> &max_nunits,
> matches, limit, &tree_size, bst_map);
> if (node)
> @@ -5651,7 +5653,6 @@ vect_lower_load_permutations (loop_vec_info
> loop_vinfo,
> unsigned limit = 1;
> unsigned tree_size = 0;
> slp_tree l0 = vect_build_slp_tree (loop_vinfo, stmts,
> - group_lanes,
> &max_nunits, matches, &limit,
> &tree_size, bst_map);
> gcc_assert (!SLP_TREE_LOAD_PERMUTATION (l0).exists ());
> --
> 2.51.0
