Add test for self-referencing emplace test.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@159921 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp b/test/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp
new file mode 100644
index 0000000..26a394f
--- /dev/null
+++ b/test/containers/sequences/vector/vector.modifiers/emplace_extra.pass.cpp
@@ -0,0 +1,34 @@
+//===----------------------------------------------------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is dual licensed under the MIT and the University of Illinois Open
+// Source Licenses. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+// <vector>
+
+// template <class... Args> iterator emplace(const_iterator pos, Args&&... args);
+
+#include <vector>
+#include <cassert>
+int main()
+{
+#ifndef _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+    {
+        std::vector<int> v;
+        v.reserve(3);
+        v = { 1, 2, 3 };
+        v.emplace(v.begin(), v.back());
+        assert(v[0] == 3);
+    }
+    {
+        std::vector<int> v;
+        v.reserve(4);
+        v = { 1, 2, 3 };
+        v.emplace(v.begin(), v.back());
+        assert(v[0] == 3);
+    }
+#endif  // _LIBCPP_HAS_NO_GENERALIZED_INITIALIZERS
+}