1 /* 2 * Copyright (c) 2021, 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 package compiler.uncommontrap; 25 26 /** 27 * @test 28 * @bug 8261730 8265132 29 * @summary Test that no anti-dependence violation is reported between a store 30 * used as an implicit null check and a load placed in the null block. 31 * @run main/othervm -XX:-BackgroundCompilation 32 * compiler.uncommontrap.TestNullCheckAntiDependence 33 */ 34 35 public class TestNullCheckAntiDependence { 36 37 private static class MyInteger { 38 int val; 39 } 40 41 private static MyInteger foo = new MyInteger(); 42 private static MyInteger bar = new MyInteger(); 43 private static MyInteger[] global = {new MyInteger()}; 44 test1()45 static void test1() { 46 for (int i = 0; i < 1; i++) { 47 // This load is placed in the null block. 48 foo.val = -bar.val; 49 for (int k = 0; k < 10; k++) { 50 // This store is hoisted and used as an implicit null check. 51 foo.val = 0; 52 } 53 } 54 } 55 test2(MyInteger a, MyInteger b)56 static void test2(MyInteger a, MyInteger b) { 57 global[0].val = a.val + b.val * 31; 58 global[0].val = 0; 59 return; 60 } 61 main(String[] args)62 public static void main(String[] args) { 63 for (int i = 0; i < 10_000; i++) { 64 test1(); 65 } 66 67 for (int i = 0; i < 10_000; i++) { 68 test2(new MyInteger(), new MyInteger()); 69 } 70 71 } 72 73 } 74