/* * Copyright (c) 2024, Red Hat, Inc. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ /* * @test * @bug 8323274 * @summary loop unswitching can cause an array load to become dependent on a test other than its range check * @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation -XX:CompileOnly=TestArrayAccessAboveRCAfterUnswitching::test * -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:StressSeed=148059521 TestArrayAccessAboveRCAfterUnswitching * @run main/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation -XX:CompileOnly=TestArrayAccessAboveRCAfterUnswitching::test * -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM TestArrayAccessAboveRCAfterUnswitching */ import java.util.Arrays; public class TestArrayAccessAboveRCAfterUnswitching { private static int field; public static void main(String[] args) { int[] array = new int[1000]; boolean[] allFalse = new boolean[1000]; boolean[] allTrue = new boolean[1000]; Arrays.fill(allTrue, true); for (int i = 0; i < 20_000; i++) { inlined(array, allFalse, 42, 2, 2, 0); inlined(array, allFalse, 2, 42, 2, 0); inlined(array, allFalse, 2, 2, 2, 0); inlined(array, allFalse, 2, 2, 42, 0); inlined(array, allTrue, 2, 2, 2, 0); test(array, allTrue, 0); } try { test(array, allTrue, -1); } catch (ArrayIndexOutOfBoundsException aioobe) { } } private static int test(int[] array, boolean[] flags, int start) { if (flags == null) { } if (array == null) { } int j = 1; for (; j < 2; j *= 2) { } int k = 1; for (; k < 2; k *= 2) { } int l = 1; for (; l < 2; l *= 2) { } int i; for (i = 0; i < 10; i += l) { } if (flags[i - 10]) { return inlined(array, flags, j, k, l, start); } return 0; } private static int inlined(int[] array, boolean[] flags, int j, int k, int l, int start) { for (int i = 0; i < 100; i++) { final boolean flag = flags[i & (j - 3)]; int v = array[(i + start) & (j - 3)]; if (flag) { return v; } if (j != 2) { field = v; } else { if (k != 2) { field = 42; } else { if (l == 2) { break; } } } } return 0; } }