This patch improves SLP reduction handling by ensuring proper processing even for a single reduction statement.Vectorization instances are now built only when there are multiple scalar statements to combine into an SLP reduction.
An example see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110632, this patch fix this problem,handling SLP reduction as expected. gcc/ChangeLog: * tree-vect-slp.cc (vect_analyze_slp): Improved handling of SLP reductions for single reduction statements. --- gcc/tree-vect-slp.cc | 49 +++++++++++++++++++++----------------------- 1 file changed, 23 insertions(+), 26 deletions(-) diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc index 55ae496cbb2..b6dfd9fd32f 100644 --- a/gcc/tree-vect-slp.cc +++ b/gcc/tree-vect-slp.cc @@ -4054,34 +4054,31 @@ vect_analyze_slp (vec_info *vinfo, unsigned max_tree_size) } } /* Save for re-processing on failure. */ - vec<stmt_vec_info> saved_stmts = scalar_stmts.copy (); - vec<stmt_vec_info> roots = vNULL; - vec<tree> remain = vNULL; - if (scalar_stmts.length () <= 1 - || !vect_build_slp_instance (loop_vinfo, - slp_inst_kind_reduc_group, - scalar_stmts, roots, remain, - max_tree_size, &limit, bst_map, - NULL)) - { - if (scalar_stmts.length () <= 1) - scalar_stmts.release (); - /* Do SLP discovery for single-lane reductions. */ - for (auto stmt_info : saved_stmts) - { - vec<stmt_vec_info> stmts; - vec<stmt_vec_info> roots = vNULL; - vec<tree> remain = vNULL; - stmts.create (1); - stmts.quick_push (vect_stmt_to_vectorize (stmt_info)); - vect_build_slp_instance (vinfo, - slp_inst_kind_reduc_group, - stmts, roots, remain, - max_tree_size, &limit, - bst_map, NULL); + if (loop_vinfo->reductions.length() > 0) { + vec<stmt_vec_info> scalar_stmts; + scalar_stmts.create(loop_vinfo->reductions.length()); + + for (auto next_info : loop_vinfo->reductions) { + if (STMT_VINFO_DEF_TYPE(next_info) == vect_reduction_def) { + gassign *g = dyn_cast<gassign*>(STMT_VINFO_STMT(next_info)); + if (!g || !lane_reducing_op_p(gimple_assign_rhs_code(g))) { + scalar_stmts.quick_push(next_info); } - saved_stmts.release (); + } } + + if (scalar_stmts.length() > 1) { + vec<stmt_vec_info> roots = vNULL; + vec<tree> remain = vNULL; + if (!vect_build_slp_instance(loop_vinfo, slp_inst_kind_reduc_group, scalar_stmts, roots, remain, max_tree_size, &limit, bst_map, NULL)) { + scalar_stmts.release(); + } + } + else { + scalar_stmts.release(); + } + } + } } -- 2.25.1
