Merge to upstream r225300.

Change-Id: I2b23715db9ac129ff80aa78ad5824db0a4d6fbb3

test/std/numerics/rand/rand.eng/rand.eng.mers/discard.pass.cpp

@@ -0,0 +1,55 @@
+//===----------------------------------------------------------------------===//
+//
+//                     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, size_t w, size_t n, size_t m, size_t r,
+//           UIntType a, size_t u, UIntType d, size_t s,
+//           UIntType b, size_t t, UIntType c, size_t l, UIntType f>
+// class mersenne_twister_engine;
+
+// void discard(unsigned long long z);
+
+#include <random>
+#include <sstream>
+#include <cassert>
+
+void
+test1()
+{
+    std::mt19937 e1;
+    std::mt19937 e2 = e1;
+    assert(e1 == e2);
+    e1.discard(3);
+    assert(e1 != e2);
+    e2();
+    e2();
+    e2();
+    assert(e1 == e2);
+}
+
+void
+test2()
+{
+    std::mt19937_64 e1;
+    std::mt19937_64 e2 = e1;
+    assert(e1 == e2);
+    e1.discard(3);
+    assert(e1 != e2);
+    e2();
+    e2();
+    e2();
+    assert(e1 == e2);
+}
+
+int main()
+{
+    test1();
+    test2();
+}