https://gcc.gnu.org/g:6ae711942f345e3b6e149431e5ce4eff9162835b
commit r17-2738-g6ae711942f345e3b6e149431e5ce4eff9162835b Author: Richard Biener <[email protected]> Date: Mon Jul 27 19:33:38 2026 +0200 tree-optimization/126417 - bogus fold-left reduction check I messed up and checked the vector type instead of the reduction number of lanes. PR tree-optimization/126417 * tree-vect-slp.cc (vectorizable_bb_reduc_epilogue): Check the total number of lanes instead of the vector type against the two-lane special case that doesn't need fold-left reduction handling. Diff: --- gcc/tree-vect-slp.cc | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc index e1112077c168..8057a10ff807 100644 --- a/gcc/tree-vect-slp.cc +++ b/gcc/tree-vect-slp.cc @@ -9212,7 +9212,7 @@ vectorizable_bb_reduc_epilogue (slp_instance instance, be included here. */ || (needs_fold_left_reduction_p (TREE_TYPE (vectype), reduc_code) && (!instance->remain_defs.is_empty () - || maybe_ne (TYPE_VECTOR_SUBPARTS (vectype), 2u)))) + || SLP_TREE_LANES (SLP_INSTANCE_TREE (instance)) != 2))) { if (dump_enabled_p ()) dump_printf_loc (MSG_MISSED_OPTIMIZATION, vect_location,
