tree-optimization/102801 - testcase for uninit diagnostic

The following testcase is fixed in GCC 12+

	PR tree-optimization/102801
gcc/testsuite/
	* g++.dg/warn/Wuninitialized-33.C: New testcase.

gcc/testsuite/g++.dg/warn/Wuninitialized-33.C

@@ -0,0 +1,55 @@
+// PR102801
+// { dg-do compile }
+// { dg-require-effective-target c++17 }
+// { dg-options "-O2 -Wall" }
+
+#include <algorithm>
+#include <memory>
+#include <optional>
+#include <string>
+#include <utility>
+#include <vector>
+
+class C {
+    bool b{}; // { dg-bogus "uninitialized" }
+
+    struct Shared {};
+    using SharedPtr = std::shared_ptr<const Shared>;
+
+    SharedPtr shared;
+
+public:
+    C() = delete;
+    C(bool bIn) : b(bIn) {}
+    ~C();
+    int someMethod() const;
+};
+
+using OptC = std::optional<C>;
+
+class C2 {
+    OptC c;
+public:
+    C2() = default;
+    C2(const C &cIn) : c(cIn) {}
+    ~C2();
+    void operator()() const;
+    void swap(C2 &o) { std::swap(c, o.c); }
+};
+
+
+template <typename T>
+class Q {
+    std::vector<T> queue;
+public:
+    void Add(std::vector<T> &items) {
+        for (T & item : items) {
+            queue.push_back(T());
+            item.swap(queue.back());
+        }
+    }
+    void Exec();
+};
+
+extern void foo(Q<C2> & q, std::vector<C2> &items);
+void foo(Q<C2> & q, std::vector<C2> &items) { q.Add(items); q.Exec(); }