1 /* 2 * Copyright (c) 2014, 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 8054478 28 * @summary dead backbranch in main loop results in erroneous array access 29 * 30 * @run main/othervm -Xcomp 31 * -XX:CompileCommand=compileonly,compiler.loopopts.TestDeadBackbranchArrayAccess::* 32 * compiler.loopopts.TestDeadBackbranchArrayAccess 33 */ 34 35 package compiler.loopopts; 36 37 public class TestDeadBackbranchArrayAccess { 38 static char[] pattern0 = {0}; 39 static char[] pattern1 = {1}; 40 41 static void test(char[] array) { 42 if (pattern1 == null) return; 43 44 int i = 0; 45 int pos = 0; 46 char c = array[pos]; 47 48 while (i >= 0 && (c == pattern0[i] || c == pattern1[i])) { 49 i--; 50 pos--; 51 if (pos != -1) { 52 c = array[pos]; 53 } 54 } 55 } 56 57 public static void main(String[] args) { 58 for (int i = 0; i < 1000000; i++) { 59 test(new char[1]); 60 } 61 } 62 }