When we split an irreducible region for BB vectorization analysis
the defensive handling of external backedge defs in
vect_get_and_check_slp_defs doesn't work since that relies on
dominance info to identify a backedge. The testcase also shows
we are iterating over the function in a sub-optimal way which is
why we split the irreducible region in the first place. The fix
is to mark backedges and use EDGE_DFS_BACK to identify them and
to use the region RPO compute which can produce a RPO order keeping
cycles in a better order (and as side effect marks backedges).
Bootstrapped and tested on x86_64-unknown-linux-gnu, pushed.
PR tree-optimization/111387
* tree-vect-slp.cc (vect_get_and_check_slp_defs): Check
EDGE_DFS_BACK when doing BB vectorization.
(vect_slp_function): Use rev_post_order_and_mark_dfs_back_seme
to compute RPO and mark backedges.
* gcc.dg/torture/pr111387.c: New testcase.
---
gcc/testsuite/gcc.dg/torture/pr111387.c | 34 +++++++++++++++++++++++++
gcc/tree-vect-slp.cc | 16 +++++++++---
2 files changed, 46 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/torture/pr111387.c
diff --git a/gcc/testsuite/gcc.dg/torture/pr111387.c
b/gcc/testsuite/gcc.dg/torture/pr111387.c
new file mode 100644
index 00000000000..e14eeef6e4a
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/torture/pr111387.c
@@ -0,0 +1,34 @@
+/* { dg-do compile } */
+/* { dg-additional-options "-ftree-vectorize -fno-vect-cost-model" } */
+
+struct {
+ unsigned a;
+ unsigned b;
+} c;
+int d, e, f, g, h;
+int main()
+{
+ if (c.b && g && g > 7)
+ goto i;
+ j:
+ if (c.a) {
+ int k = 0;
+ unsigned l = c.b;
+ if (0) {
+ m:
+ k = l = c.b;
+ }
+ c.a = k;
+ c.b = l;
+ }
+ if (0) {
+ i:
+ goto m;
+ }
+ if (d)
+ goto j;
+ for (f = 5; f; f--)
+ if (h)
+ e = 0;
+ return 0;
+}
diff --git a/gcc/tree-vect-slp.cc b/gcc/tree-vect-slp.cc
index 0cf6e02285e..a3e54ebf62a 100644
--- a/gcc/tree-vect-slp.cc
+++ b/gcc/tree-vect-slp.cc
@@ -628,9 +628,13 @@ vect_get_and_check_slp_defs (vec_info *vinfo, unsigned
char swap,
{
oprnd = gimple_arg (stmt_info->stmt, opno);
if (gphi *stmt = dyn_cast <gphi *> (stmt_info->stmt))
- backedge = dominated_by_p (CDI_DOMINATORS,
- gimple_phi_arg_edge (stmt, opno)->src,
- gimple_bb (stmt_info->stmt));
+ {
+ edge e = gimple_phi_arg_edge (stmt, opno);
+ backedge = (is_a <bb_vec_info> (vinfo)
+ ? e->flags & EDGE_DFS_BACK
+ : dominated_by_p (CDI_DOMINATORS, e->src,
+ gimple_bb (stmt_info->stmt)));
+ }
}
if (TREE_CODE (oprnd) == VIEW_CONVERT_EXPR)
oprnd = TREE_OPERAND (oprnd, 0);
@@ -7771,7 +7775,11 @@ vect_slp_function (function *fun)
{
bool r = false;
int *rpo = XNEWVEC (int, n_basic_blocks_for_fn (fun));
- unsigned n = pre_and_rev_post_order_compute_fn (fun, NULL, rpo, false);
+ auto_bitmap exit_bbs;
+ bitmap_set_bit (exit_bbs, EXIT_BLOCK);
+ edge entry = single_succ_edge (ENTRY_BLOCK_PTR_FOR_FN (fun));
+ unsigned n = rev_post_order_and_mark_dfs_back_seme (fun, entry, exit_bbs,
+ true, rpo, NULL);
/* For the moment split the function into pieces to avoid making
the iteration on the vector mode moot. Split at points we know
--
2.35.3
