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 /** 25 * @test 26 * @bug 8262739 27 * @summary Test correct insertion of anti-dependencies after String inflation. 28 * @run main/othervm -Xbatch 29 * compiler.controldependency.TestAntiDependencyAfterStringInflation 30 */ 31 32 package compiler.controldependency; 33 34 public class TestAntiDependencyAfterStringInflation { 35 36 static String reverseString(String str) { 37 int size = str.length(); 38 char[] buffer = new char[size]; 39 reverse(str, buffer, size); 40 return new String(buffer, 0, size); 41 } 42 43 static void reverse(String str, char[] buffer, int size) { 44 // Inflate String.value byte[] to char[] 45 str.getChars(0, size, buffer, 0); 46 // Reverse String by copying buffer elements. This will fail 47 // if C2 does not insert anti-dependencies between loads/stores. 48 int half = size / 2; 49 for (int l = 0, r = size - 1; l < half; l++, r--) { 50 char tmp = buffer[l]; 51 buffer[l] = buffer[r]; 52 buffer[r] = tmp; 53 } 54 } 55 56 public static void main(String[] args) throws Exception { 57 for (int i = 0; i < 50_000; i++) { 58 String res = reverseString("0123456789"); 59 if (!res.equals("9876543210")) { 60 throw new RuntimeException("Unexpected result: " + res); 61 } 62 } 63 } 64 }