/*

 * Copyright (c) 2014, 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.

 *

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 */

/*

 * @test

 * @bug 8015499

 * @summary javac, Gen is generating extra checkcast instructions in some corner cases

 *          jdk.compiler/com.sun.tools.javac.util

 * @run main DoubleCastTest

 */

import java.util.List;

import java.util.ArrayList;

import com.sun.tools.classfile.*;

import com.sun.tools.javac.util.Assert;

public class DoubleCastTest {

    class C {

        Object x;

        Object m() { return null; }

        void m1(byte[] b) {}

        void m2() {

            Object o;

            Object[] os = null;

            m1((byte[])(o = null));

            m1((byte[])o);

            m1((byte[])(o == null ? o : o));

            m1((byte[])m());

            m1((byte[])os[0]);

            m1((byte[])this.x);

            m1((byte[])((byte []) (o = null)));

        }

    }

    public static void main(String... cmdline) throws Exception {

        ClassFile cls = ClassFile.read(DoubleCastTest.class.getResourceAsStream("DoubleCastTest$C.class"));

        for (Method m: cls.methods)

            check(m);

    }

    static void check(Method m) throws Exception {

        boolean last_is_cast = false;

        int last_ref = 0;

        Code_attribute ea = (Code_attribute)m.attributes.get(Attribute.Code);

        for (Instruction i : ea.getInstructions()) {

            if (i.getOpcode() == Opcode.CHECKCAST) {

                Assert.check

                    (!(last_is_cast && last_ref == i.getUnsignedShort(1)),

                     "Double cast found - Test failed");

                last_is_cast = true;

                last_ref = i.getUnsignedShort(1);

            } else {

                last_is_cast = false;

            }

        }

    }

}