We can use TBAA even when we have a DR, do so. For the testcase
that means fully vectorizing it instead of only vectorizing
the first store group resulting in suboptimal code.
Bootstrapped and tested on x86_64-unknown-linux-gnu, queued for stage1.
2021-04-09 Richard Biener <rguent...@suse.de>
PR tree-optimization/99971
* tree-vect-data-refs.c (vect_slp_analyze_node_dependences):
Always use TBAA for loads.
* g++.dg/vect/slp-pr99971.cc: New testcase.
---
gcc/testsuite/g++.dg/vect/slp-pr99971.cc | 36 ++++++++++++++++++++++++
gcc/tree-vect-data-refs.c | 18 +++++++-----
2 files changed, 47 insertions(+), 7 deletions(-)
create mode 100644 gcc/testsuite/g++.dg/vect/slp-pr99971.cc
diff --git a/gcc/testsuite/g++.dg/vect/slp-pr99971.cc
b/gcc/testsuite/g++.dg/vect/slp-pr99971.cc
new file mode 100644
index 00000000000..bec6418d4e8
--- /dev/null
+++ b/gcc/testsuite/g++.dg/vect/slp-pr99971.cc
@@ -0,0 +1,36 @@
+// { dg-do compile }
+// { dg-require-effective-target vect_int }
+
+struct A
+{
+ unsigned int a, b, c, d;
+
+ A& operator+= (A const& that)
+ {
+ a += that.a;
+ b += that.b;
+ c += that.c;
+ d += that.d;
+ return *this;
+ }
+
+ A& operator-= (A const& that)
+ {
+ a -= that.a;
+ b -= that.b;
+ c -= that.c;
+ d -= that.d;
+ return *this;
+ }
+};
+
+void test(A& x, A const& y1, A const& y2)
+{
+ x += y1;
+ x -= y2;
+}
+
+// We want to SLP vectorize a single connected SLP subgraph with two instances
+// { dg-final { scan-tree-dump-not "removing SLP instance" "slp2" } }
+// { dg-final { scan-tree-dump-times "SLPing BB part" 1 "slp2" } }
+// { dg-final { scan-tree-dump-times "Vectorizing SLP" 2 "slp2" } }
diff --git a/gcc/tree-vect-data-refs.c b/gcc/tree-vect-data-refs.c
index ee266ba62a8..6ea5e3a3eda 100644
--- a/gcc/tree-vect-data-refs.c
+++ b/gcc/tree-vect-data-refs.c
@@ -780,16 +780,20 @@ vect_slp_analyze_node_dependences (vec_info *vinfo,
slp_tree node,
stmt we have to resort to the alias oracle. */
stmt_vec_info stmt_info = vinfo->lookup_stmt (stmt);
data_reference *dr_b = STMT_VINFO_DATA_REF (stmt_info);
- if (!dr_b)
+
+ /* We are hoisting a load - this means we can use
+ TBAA for disambiguation. */
+ if (!ref_initialized_p)
+ ao_ref_init (&ref, DR_REF (dr_a));
+ if (stmt_may_clobber_ref_p_1 (stmt, &ref, true))
{
- /* We are hoisting a load - this means we can use
- TBAA for disambiguation. */
- if (!ref_initialized_p)
- ao_ref_init (&ref, DR_REF (dr_a));
- if (stmt_may_clobber_ref_p_1 (stmt, &ref, true))
+ if (!dr_b)
return false;
- continue;
+ /* Resort to dependence checking below. */
}
+ else
+ /* No dependence. */
+ continue;
bool dependent = false;
/* If we run into a store of this same instance (we've just
--
2.26.2
