https://gcc.gnu.org/g:5e45cc08f3bbbfa77b6e6524127f7acbec1d2c83
commit r17-2817-g5e45cc08f3bbbfa77b6e6524127f7acbec1d2c83 Author: Richard Biener <[email protected]> Date: Wed Jul 29 14:26:42 2026 +0200 Avoid SSA copies from vect_add_slp_permutation In the past we needed a stmt_vec_info for all vector defs. Not anymore. * tree-vect-slp.cc (vect_add_slp_permutation): We no longer need a copy when the extraction is readily available. (vect_schedule_slp_node): Handle default defs or constants in vector defs. Diff: --- gcc/tree-vect-slp.cc | 31 +++++++++++++++++-------------- 1 file changed, 17 insertions(+), 14 deletions(-) diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc index 8057a10ff807..e350d8040f5e 100644 --- a/gcc/tree-vect-slp.cc +++ b/gcc/tree-vect-slp.cc @@ -11365,7 +11365,6 @@ vect_add_slp_permutation (vec_info *vinfo, gimple_stmt_iterator *gsi, first_def = gimple_assign_lhs (conv_stmt); } gassign *perm_stmt; - tree perm_dest = make_ssa_name (vectype); if (mask_vec) { if (operand_equal_p (TYPE_SIZE (TREE_TYPE (first_def)), @@ -11379,6 +11378,7 @@ vect_add_slp_permutation (vec_info *vinfo, gimple_stmt_iterator *gsi, vect_finish_stmt_generation (vinfo, NULL, conv_stmt, gsi); second_def = gimple_assign_lhs (conv_stmt); } + tree perm_dest = make_ssa_name (vectype); perm_stmt = gimple_build_assign (perm_dest, VEC_PERM_EXPR, first_def, second_def, mask_vec); @@ -11396,6 +11396,7 @@ vect_add_slp_permutation (vec_info *vinfo, gimple_stmt_iterator *gsi, { /* For identity permutes we still need to handle the case of offsetted extracts or concats. */ + tree perm_dest = make_ssa_name (vectype); unsigned HOST_WIDE_INT c; if (known_le (TYPE_VECTOR_SUBPARTS (vectype), def_nunits)) { @@ -11420,9 +11421,9 @@ vect_add_slp_permutation (vec_info *vinfo, gimple_stmt_iterator *gsi, } else { - /* We need a copy here in case the def was external. */ gcc_assert (known_eq (eltno, 0U)); - perm_stmt = gimple_build_assign (perm_dest, def); + node->push_vec_def (def); + return; } } vect_finish_stmt_generation (vinfo, NULL, perm_stmt, gsi); @@ -11929,17 +11930,19 @@ vect_schedule_slp_node (vec_info *vinfo, unsigned j; tree vdef; FOR_EACH_VEC_ELT (SLP_TREE_VEC_DEFS (child), j, vdef) - { - gimple *vstmt = SSA_NAME_DEF_STMT (vdef); - if (!last_stmt) - last_stmt = vstmt; - else if (vect_stmt_dominates_stmt_p (last_stmt, vstmt)) - last_stmt = vstmt; - else if (vect_stmt_dominates_stmt_p (vstmt, last_stmt)) - ; - else - gcc_unreachable (); - } + if (TREE_CODE (vdef) == SSA_NAME + && !SSA_NAME_IS_DEFAULT_DEF (vdef)) + { + gimple *vstmt = SSA_NAME_DEF_STMT (vdef); + if (!last_stmt) + last_stmt = vstmt; + else if (vect_stmt_dominates_stmt_p (last_stmt, vstmt)) + last_stmt = vstmt; + else if (vect_stmt_dominates_stmt_p (vstmt, last_stmt)) + ; + else + gcc_unreachable (); + } } else if (!SLP_TREE_VECTYPE (child)) {
