From 21edcb95340424efe2e66831f3b32cbab9cc6d31 Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Thu, 9 Jan 2025 11:51:19 +0100 Subject: Fix SLP scalar costing with stmts also used in externals When we have the situation of an external SLP node that is permuted the scalar stmts recorded in the permute node do not mean the scalar computation can be removed. We are removing those stmts from the vectorized_scalar_stmts for this reason but we fail to check this set when we cost scalar stmts. Note vectorized_scalar_stmts isn't a complete set so also pass scalar_stmts_in_externs and check that. The following fixes this. This shows in PR115777 when we avoid vectorizing the load, but on it's own doesn't help the PR yet. PR tree-optimization/115777 * tree-vect-slp.cc (vect_bb_slp_scalar_cost): Do not cost a scalar stmt that needs to be preserved. --- gcc/tree-vect-slp.cc | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'gcc') diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc index 02e7f5c..1d8e62e 100644 --- a/gcc/tree-vect-slp.cc +++ b/gcc/tree-vect-slp.cc @@ -8676,6 +8676,7 @@ vect_bb_slp_scalar_cost (vec_info *vinfo, slp_tree node, vec *life, stmt_vector_for_cost *cost_vec, hash_set &vectorized_scalar_stmts, + hash_set &scalar_stmts_in_externs, hash_set &visited) { unsigned i; @@ -8690,7 +8691,12 @@ vect_bb_slp_scalar_cost (vec_info *vinfo, ssa_op_iter op_iter; def_operand_p def_p; - if (!stmt_info || (*life)[i]) + if (!stmt_info + || (*life)[i] + /* Defs also used in external nodes are not in the + vectorized_scalar_stmts set as they need to be preserved. + Honor that. */ + || scalar_stmts_in_externs.contains (stmt_info)) continue; stmt_vec_info orig_stmt_info = vect_orig_stmt (stmt_info); @@ -8809,7 +8815,8 @@ next_lane: subtree_life.safe_splice (*life); } vect_bb_slp_scalar_cost (vinfo, child, &subtree_life, cost_vec, - vectorized_scalar_stmts, visited); + vectorized_scalar_stmts, + scalar_stmts_in_externs, visited); subtree_life.truncate (0); } } @@ -8891,7 +8898,7 @@ vect_bb_vectorization_profitable_p (bb_vec_info bb_vinfo, vect_bb_slp_scalar_cost (bb_vinfo, SLP_INSTANCE_TREE (instance), &life, &scalar_costs, vectorized_scalar_stmts, - visited); + scalar_stmts_in_externs, visited); vector_costs.safe_splice (instance->cost_vec); instance->cost_vec.release (); } -- cgit v1.1