new file mode 100644
@@ -0,0 +1,48 @@
+// { dg-do compile }
+// { dg-require-effective-target c++17 }
+// { dg-additional-options "-Wall" }
+// -O1 doesn't iterate VN and thus has bogus uninit diagnostics
+// { dg-skip-if "" { *-*-* } { "-O1" } { "" } }
+
+#include <vector>
+
+#include <optional>
+template <class T>
+using Optional = std::optional<T>;
+
+#include <sstream>
+
+struct MyOptionalStructWithInt {
+ int myint; /* works without this */
+ Optional<std::vector<std::string>> myoptional;
+};
+
+struct MyOptionalsStruct {
+ MyOptionalStructWithInt external1;
+ MyOptionalStructWithInt external2;
+};
+
+struct MyStruct { };
+std::ostream &operator << (std::ostream &os, const MyStruct &myStruct);
+
+std::vector<MyStruct> getMyStructs();
+
+void test()
+{
+ MyOptionalsStruct externals;
+ MyOptionalStructWithInt internal1;
+ MyOptionalStructWithInt internal2;
+
+ std::vector<MyStruct> myStructs;
+ myStructs = getMyStructs();
+
+ for (const auto& myStruct : myStructs)
+ {
+ std::stringstream address_stream;
+ address_stream << myStruct;
+ internal1.myint = internal2.myint = 0;
+ externals.external1 = internal1;
+ externals.external2 = internal2;
+ externals.external2 = internal2;
+ }
+}
@@ -2680,7 +2680,6 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
if (is_gimple_reg_type (TREE_TYPE (lhs))
&& types_compatible_p (TREE_TYPE (lhs), vr->type)
&& (ref->ref || data->orig_ref.ref)
- && !data->same_val
&& !data->mask
&& data->partial_defs.is_empty ()
&& multiple_p (get_object_alignment
@@ -2693,8 +2692,13 @@ vn_reference_lookup_3 (ao_ref *ref, tree vuse, void *data_,
a different loop iteration but only to loop invariants. Use
CONSTANT_CLASS_P (unvalueized!) as conservative approximation.
The one-hop lookup below doesn't have this issue since there's
- a virtual PHI before we ever reach a backedge to cross. */
- if (CONSTANT_CLASS_P (rhs))
+ a virtual PHI before we ever reach a backedge to cross.
+ We can skip multiple defs as long as they are from the same
+ value though. */
+ if (data->same_val
+ && !operand_equal_p (data->same_val, rhs))
+ ;
+ else if (CONSTANT_CLASS_P (rhs))
{
if (dump_file && (dump_flags & TDF_DETAILS))
{