1 /*
   2  * Copyright (c) 2015, 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 8080156 8060036
  27  * @summary Test correctness of type propagation to CmpUNodes.
  28  * @run main TestTypePropagationToCmpU
  29  */
  30 public class TestTypePropagationToCmpU {
  31     public static void main(String[] args) {
  32         try {
  33             // Trigger compilation
  34             for (int i = 0; i < 100_000; ++i) {
  35                 test();
  36             }
  37         } catch (NullPointerException e) {
  38             // Test should never throw a NullPointerException
  39             throw new RuntimeException("Test failed");
  40         }
  41     }
  42 
  43     static int global = 42;
  44 
  45     public static void test() {
  46         int a = Integer.MIN_VALUE;
  47         int b = global;
  48         char[] buf = { 0 };
  49         for (int i = 0; i <= b; ++i) {
  50             a = i - b;
  51         }
  52         // C2 adds a range check and an uncommon trap here to ensure that the array index
  53         // is in bounds. If type information is not propagated correctly to the corresponding
  54         // CmpUNode, this trap may be always taken. Because C2 also removes the unnecessary
  55         // allocation of 'buf', a NullPointerException is thrown in this case.
  56         char c = buf[(a * 11) / 2 - a]; // a is 0 here if global >= 0
  57         buf[0] = 0;
  58     }
  59 }