8075587: Compilation of constant array containing different sub classes crashes the JVM

Summary: meet of 2 constant arrays result in bottom
Reviewed-by: kvn

src/share/vm/opto/type.cpp

@@ -3950,7 +3950,9 @@ const Type *TypeAryPtr::xmeet_helper(const Type *t) const {
            (tap->_klass_is_exact && !tap->klass()->is_subtype_of(klass())) ||
            // 'this' is exact and super or unrelated:
            (this->_klass_is_exact && !klass()->is_subtype_of(tap->klass())))) {
-      tary = TypeAry::make(Type::BOTTOM, tary->_size, tary->_stable);
+      if (above_centerline(ptr)) {
+        tary = TypeAry::make(Type::BOTTOM, tary->_size, tary->_stable);
+      }
       return make(NotNull, NULL, tary, lazy_klass, false, off, InstanceBot);
     }
 

test/compiler/types/TestMeetExactConstantArrays.java

+/*
+ * Copyright (c) 2015, 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 8075587
+ * @summary meet of 2 constant arrays result in bottom
+ * @run main/othervm TestMeetExactConstantArrays
+ *
+ */
+
+public class TestMeetExactConstantArrays {
+    public abstract static class NumbersHolder {
+        public Number[] getNumbers() {
+            return null;
+        }
+    }
+
+    public static class IntegersHolder extends NumbersHolder {
+        private final static Integer integers[] = { new Integer(1) };
+
+        public Number[] getNumbers() {
+            return integers;
+        }
+    }
+
+    public static class LongsHolder extends NumbersHolder {
+        private final static Long longs[] = { new Long(1) };
+
+        public Number[] getNumbers() {
+            return longs;
+        }
+    }
+
+    public static final void loopNumbers(NumbersHolder numbersHolder) {
+        Number[] numbers = numbersHolder.getNumbers();
+        for (int i = 0; i < numbers.length; i++) {
+            numbers[i].longValue();
+        }
+    }
+
+    public static void main(String[] args) throws Exception {
+        for (int i = 0; i < 10000; i++) {
+            IntegersHolder integersHolder = new IntegersHolder();
+            LongsHolder longsHolder = new LongsHolder();
+            loopNumbers(integersHolder);
+            loopNumbers(longsHolder);
+        }
+    }
+}