Test6897150.java revision 11707:ad7af1afda7a 
1/*
2 * Copyright (c) 2011, 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 6897150
28 * @summary Hotspot optimises away a valid loop
29 *
30 * @run main compiler.c2.Test6897150
31 */
32
33package compiler.c2;
34
35// Should be compiled with javac from JDK1.3 to get bytecode which shows the problem.
36public class Test6897150 {
37    public static void main(String[] args) {
38        // This works
39        loopAndPrint(Integer.MAX_VALUE -1);
40        // This doesn't
41        loopAndPrint(Integer.MAX_VALUE);
42    }
43
44    static void verify(int max, int a) {
45        if ( a != (max - 1)) {
46            System.out.println("Expected: " + (max - 1));
47            System.out.println("Actual  : " + a);
48            System.exit(97);
49        }
50    }
51    static void loopAndPrint(int max) {
52        int a = -1;
53        int i = 1;
54        for (; i < max; i++) {
55            a = i;
56        }
57        verify(max, a);
58    }
59}
60
61