--- /dev/null	2016-03-14 08:53:49.338291982 +0100
+++ new/test/compiler/types/TestPhiElimination.java	2016-03-14 13:15:27.031411260 +0100
@@ -0,0 +1,112 @@
+/*
+ * Copyright (c) 2016, Oracle and/or its affiliates. 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 8150804
+ * @summary Tests elimination of Phi nodes without losing type information.
+ * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestPhiElimination
+ */
+public class TestPhiElimination {
+    /*
+       A::get() is inlined into test(obj) producing the following graph:
+
+               Parm (obj)
+            TestPhiElimination
+                   |
+                 CastPP
+        TestPhiElimination:NotNull
+                   |
+              CheckCastPP
+               A:NotNull
+               /       \
+       CheckCastPP     |
+        A:NotNull      |
+                \     /
+                  Phi
+                   A
+                   |
+               Safepoint
+
+       PhiNode::ideal() then replaces the Phi by a CheckCastPP:
+
+               Parm (obj)
+            TestPhiElimination
+                   |
+              CheckCastPP
+                   A
+                   |
+               Safepoint
+
+       losing the :NotNull information. Therefore, we cannot prove that obj != null
+       when accessing a field and add an uncommon trap. Since obj is used as monitor, we
+       set it to TOP in the uncommon trap branch and later fail in Process_OopMap_Node
+       because the monitor object is TOP.
+    */
+    public Object test(TestPhiElimination obj) {
+        if (obj instanceof A) {
+            return ((A) obj).get();
+        }
+        return null;
+    }
+
+    static public void main(String[] args) {
+        TestPhiElimination t = new TestPhiElimination();
+
+        // Warmup
+        B b = new B();
+        for (int i = 0; i < 1_000; ++i) {
+            t.test(b);
+        }
+
+        // Compile
+        A a = new A();
+        for (int i = 0; i < 20_000; ++i) {
+            if (i % 2 == 0) {
+                a.f = null;
+            }
+            t.test(a);
+        }
+    }
+
+}
+
+class A extends TestPhiElimination {
+    public Object f;
+
+    public A create() {
+        return new A();
+    }
+
+    public synchronized Object get() {
+        if (f == null) {
+            f = create();
+        }
+        return f;
+    }
+}
+
+class B extends A {
+
+}