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 * @test
26 * @bug 8054478
27 * @summary dead backbranch in main loop results in erroneous array access
28 *
29 * @run main/othervm -Xcomp
30 *      -XX:CompileCommand=compileonly,compiler.loopopts.TestDeadBackbranchArrayAccess::*
31 *      compiler.loopopts.TestDeadBackbranchArrayAccess
32 */
33
34package compiler.loopopts;
35
36public class TestDeadBackbranchArrayAccess {
37    static char[] pattern0 = {0};
38    static char[] pattern1 = {1};
39
40    static void test(char[] array) {
41        if (pattern1 == null) return;
42
43        int i = 0;
44        int pos = 0;
45        char c = array[pos];
46
47        while (i >= 0 && (c == pattern0[i] || c == pattern1[i])) {
48            i--;
49            pos--;
50            if (pos != -1) {
51                c = array[pos];
52            }
53        }
54    }
55
56    public static void main(String[] args) {
57        for (int i = 0; i < 1000000; i++) {
58            test(new char[1]);
59        }
60    }
61}
62