--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/hotspot/test/compiler/unsafe/TestMaybeNullUnsafeAccess.java	Mon May 29 18:17:49 2017 +0200
@@ -0,0 +1,97 @@
+/*
+ * Copyright (c) 2017, Red Hat, Inc. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+/**
+ * @test
+ * @bug 8176506
+ * @summary cast before unsafe access moved in dominating null check null path causes crash
+ * @modules java.base/jdk.internal.misc:+open
+ *
+ * @run main/othervm -Xbatch -XX:-UseOnStackReplacement TestMaybeNullUnsafeAccess
+ *
+ */
+
+import jdk.internal.misc.Unsafe;
+import java.lang.reflect.Field;
+
+public class TestMaybeNullUnsafeAccess {
+
+    static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe();
+    static final long F_OFFSET;
+
+    static class A {
+        int f;
+        A(int f) {
+            this.f = f;
+        }
+    }
+
+    static {
+        try {
+            Field fField = A.class.getDeclaredField("f");
+            F_OFFSET = UNSAFE.objectFieldOffset(fField);
+        } catch (Exception e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    static A test_helper(Object o) {
+        // this includes a check for null with both branches taken
+        return (A)o;
+    }
+
+
+    // Loop is unswitched because of the test for null from the
+    // checkcast above, unsafe access is copied in each branch, the
+    // compiler sees a memory access to a null object
+    static int test1(Object o, long offset) {
+        int f = 0;
+        for (int i = 0; i < 100; i++) {
+            A a = test_helper(o);
+            f = UNSAFE.getInt(a, offset);
+        }
+        return f;
+    }
+
+    // Same as above except because we know the offset of the access
+    // is small, we can deduce object a cannot be null
+    static int test2(Object o) {
+        int f = 0;
+        for (int i = 0; i < 100; i++) {
+            A a = test_helper(o);
+            f = UNSAFE.getInt(a, F_OFFSET);
+        }
+        return f;
+    }
+
+    static public void main(String[] args) {
+        A a = new A(0x42);
+        for (int i = 0; i < 20000; i++) {
+            test_helper(null);
+            test_helper(a);
+            test1(a, F_OFFSET);
+            test2(a);
+        }
+    }
+
+}