https://gcc.gnu.org/g:1e8bd720b1a618a39e2a41eec05e935c32d295f3
commit r16-473-g1e8bd720b1a618a39e2a41eec05e935c32d295f3
Author: Richard Biener <rguent...@suse.de>
Date: Thu May 8 10:56:16 2025 +0200
tree-optimization/116352 - amend previous fix
The previous fix restricted external vector builds to defs from
the same basic-block. That turns out too restrictive so we have
to mitigate the original issue in a different way which is
restricting it to the original case where all defs are in the
same basic-block.
PR tree-optimization/116352
* tree-vect-slp.cc (vect_build_slp_tree_2): When compressing
operands from a two-operator node make sure the resulting
operation does not mix defs from different basic-blocks.
Diff:
---
gcc/tree-vect-slp.cc | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 80e9c010b1a1..2774fd23dfa7 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -2617,13 +2617,14 @@ out:
if (oprnds_info[0]->def_stmts[0]
&& is_a<gassign *> (oprnds_info[0]->def_stmts[0]->stmt))
code = gimple_assign_rhs_code (oprnds_info[0]->def_stmts[0]->stmt);
+ basic_block bb = nullptr;
for (unsigned j = 0; j < group_size; ++j)
{
FOR_EACH_VEC_ELT (oprnds_info, i, oprnd_info)
{
stmt_vec_info stmt_info = oprnd_info->def_stmts[j];
- if (!stmt_info || !stmt_info->stmt
+ if (!stmt_info
|| !is_a<gassign *> (stmt_info->stmt)
|| gimple_assign_rhs_code (stmt_info->stmt) != code
|| skip_args[i])
@@ -2631,6 +2632,14 @@ out:
success = false;
break;
}
+ /* Avoid mixing lanes with defs in different basic-blocks. */
+ if (!bb)
+ bb = gimple_bb (vect_orig_stmt (stmt_info)->stmt);
+ else if (gimple_bb (vect_orig_stmt (stmt_info)->stmt) != bb)
+ {
+ success = false;
+ break;
+ }
bool exists;
unsigned &stmt_idx
