1 /*

     2  * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 /**

    26  * @test

    27  * @bug 8054478

    28  * @summary dead backbranch in main loop results in erroneous array access

    29  * @run main/othervm -XX:CompileOnly=TestDeadBackbranchArrayAccess -Xcomp TestDeadBackbranchArrayAccess

    30  *

    31  */

    32 

    33 public class TestDeadBackbranchArrayAccess {

    34     static char[] pattern0 = {0};

    35     static char[] pattern1 = {1};

    36 

    37     static void test(char[] array) {

    38         if (pattern1 == null) return;

    39 

    40         int i = 0;

    41         int pos = 0;

    42         char c = array[pos];

    43 

    44         while (i >= 0 && (c == pattern0[i] || c == pattern1[i])) {

    45             i--;

    46             pos--;

    47             if (pos != -1) {

    48                 c = array[pos];

    49             }

    50         }

    51     }

    52 

    53     public static void main(String[] args) {

    54         for (int i = 0; i < 1000000; i++) {

    55             test(new char[1]);

    56         }

    57     }

    58 }