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 Test6897150
  31  */
  32 
  33 // Should be compiled with javac from JDK1.3 to get bytecode which shows the problem.
  34 public class Test6897150 {
  35     public static void main(String[] args) {
  36         // This works
  37         loopAndPrint(Integer.MAX_VALUE -1);
  38         // This doesn't
  39         loopAndPrint(Integer.MAX_VALUE);
  40     }
  41 
  42     static void verify(int max, int a) {
  43         if ( a != (max - 1)) {
  44             System.out.println("Expected: " + (max - 1));
  45             System.out.println("Actual  : " + a);
  46             System.exit(97);
  47         }
  48     }
  49     static void loopAndPrint(int max) {
  50         int a = -1;
  51         int i = 1;
  52         for (; i < max; i++) {
  53             a = i;
  54         }
  55         verify(max, a);
  56     }
  57 }
  58