1 /*

     2  * Copyright (c) 2018, 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

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    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

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    23 

    24 /**

    25  * @test

    26  * @bug 8214994

    27  * @summary The split-if optimization fails because an unexpected Opaque1 is encountered.

    28  * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:-UseOnStackReplacement -XX:-BackgroundCompilation

    29  *                   compiler.loopopts.TestSplitIfOpaque1

    30  */

    31 

    32 package compiler.loopopts;

    33 

    34 public class TestSplitIfOpaque1 {

    35 

    36     static class MyClass {

    37         int f;

    38         MyClass(int f) {

    39             this.f = f;

    40         }

    41     }

    42 

    43     // The inner loop is found to be a counted loop and a loop limit check

    44     // is added by updating the Opaque1 input of the predicate template.

    45     // This Opaque1 node is then pushed upwards to before the predicates of

    46     // the outer loop and ends up right after the second 'if (b)'.

    47     // The split-if optimization kicks in and splits the first predicate of

    48     // the outer loop (an "obj != NULL" check) through the 'if (b)' region.

    49     // We fail because the region contains an unexpected Opaque1 node.

    50     static int test1(boolean b, int limit, MyClass obj) {

    51         int res = 0;

    52         MyClass notNull = new MyClass(42);

    53         if (b) {

    54             limit = 100;

    55         }

    56         if (b) {

    57             obj = notNull;

    58         }

    59         for (int i = 0; i < 1000; ++i) {

    60             res += obj.f;

    61             for (int j = 0; j <= limit; ++j) {

    62                 // Empty

    63             }

    64         }

    65         return res;

    66     }

    67 

    68     // Same as test1 but triggers slightly different failure mode

    69     static int test2(boolean b, int limit, MyClass obj, int[] array) {

    70         int res = 0;

    71         MyClass notNull = new MyClass(12);

    72         if (b) {

    73             limit = 100;

    74         }

    75         if (b) {

    76             obj = notNull;

    77         }

    78         for (int i = 0; i < 1000; ++i) {

    79             res += obj.f;

    80             for (int j = 0; j <= limit; ++j) {

    81                 array[j] = j;

    82             }

    83         }

    84         return res;

    85     }

    86 

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

    88         MyClass obj = new MyClass(42);

    89         int[] array = new int[101];

    90         for (int i = 0; i < 20_000; i++) {

    91             test1(true, 50, obj);

    92             test1(false, 100, obj);

    93             test2(true, 50, obj, array);

    94             test2(false, 100, obj, array);

    95         }

    96     }

    97 }