--- /dev/null	2018-04-03 12:55:20.301839954 +0200
+++ new/test/hotspot/gtest/gc/z/test_zUtils.cpp	2018-06-01 22:31:26.121845373 +0200
@@ -0,0 +1,56 @@
+/*
+ * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
+ * ORACLE PROPRIETARY/CONFIDENTIAL.  Use is subject to license terms.
+ */
+
+#include "precompiled.hpp"
+#include "gc/z/zUtils.inline.hpp"
+#include "unittest.hpp"
+
+#include <limits>
+
+template <typename T>
+static T max_alignment() {
+  T max = std::numeric_limits<T>::max();
+  return max ^ (max >> 1);
+}
+
+TEST(ZUtilsTest, round_up_power_of_2) {
+  EXPECT_EQ(ZUtils::round_up_power_of_2(1u), 1u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(2u), 2u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(3u), 4u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(4u), 4u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(5u), 8u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(6u), 8u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(7u), 8u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(8u), 8u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(9u), 16u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(10u), 16u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(1023u), 1024u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(1024u), 1024u);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(1025u), 2048u);
+
+  const size_t max = max_alignment<size_t>();
+  EXPECT_EQ(ZUtils::round_up_power_of_2(max - 1), max);
+  EXPECT_EQ(ZUtils::round_up_power_of_2(max), max);
+}
+
+TEST(ZUtilsTest, round_down_power_of_2) {
+  EXPECT_EQ(ZUtils::round_down_power_of_2(1u), 1u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(2u), 2u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(3u), 2u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(4u), 4u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(5u), 4u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(6u), 4u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(7u), 4u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(8u), 8u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(9u), 8u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(10u), 8u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(1023u), 512u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(1024u), 1024u);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(1025u), 1024u);
+
+  const size_t max = max_alignment<size_t>();
+  EXPECT_EQ(ZUtils::round_down_power_of_2(max), max);
+  EXPECT_EQ(ZUtils::round_down_power_of_2(max - 1), max / 2);
+}