Merge to upstream r225300.

Change-Id: I2b23715db9ac129ff80aa78ad5824db0a4d6fbb3

test/std/numerics/rand/rand.eng/rand.eng.lcong/io.pass.cpp

@@ -0,0 +1,44 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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.
+//
+//===----------------------------------------------------------------------===//
+
+// <random>
+
+// template <class UIntType, UIntType a, UIntType c, UIntType m>
+//   class linear_congruential_engine;
+
+// template <class charT, class traits,
+//           class UIntType, UIntType a, UIntType c, UIntType m>
+// basic_ostream<charT, traits>&
+// operator<<(basic_ostream<charT, traits>& os,
+//            const linear_congruential_engine<UIntType, a, c, m>& x);
+//
+// template <class charT, class traits,
+//           class UIntType, UIntType a, UIntType c, UIntType m>
+// basic_istream<charT, traits>&
+// operator>>(basic_istream<charT, traits>& is,
+//            linear_congruential_engine<UIntType, a, c, m>& x);
+
+#include <random>
+#include <sstream>
+#include <cassert>
+
+int main()
+{
+    {
+        typedef std::linear_congruential_engine<unsigned, 48271, 0, 2147483647> E;
+        E e1;
+        e1.discard(100);
+        std::ostringstream os;
+        os << e1;
+        std::istringstream is(os.str());
+        E e2;
+        is >> e2;
+        assert(e1 == e2);
+    }
+}