/* * Copyright (c) 2025 IBM Corporation. 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 8373524 * @summary C2: no reachable node should have no use * @run main/othervm -Xbatch ${test.main.class} * @run main ${test.main.class} */ package compiler.igvn; public class TestNodeWithNoUseAfterPhiIdeal { volatile boolean _mutatorToggle; boolean _mutatorFlip() { synchronized (TestNodeWithNoUseAfterPhiIdeal.class) { _mutatorToggle = new MyBoolean(!_mutatorToggle).v; return _mutatorToggle; } } class MyBoolean { boolean v; MyBoolean(boolean v) { int N = 32; for (int i = 0; i < N; i++) { this.v = v; } } } int[] arr; void test() { int limit = 2; boolean flag1 = _mutatorFlip(); for (; limit < 4; limit *= 2) { if (flag1) { break; } } int zero = 34; for (int peel = 2; peel < limit; peel++) { synchronized (TestNodeWithNoUseAfterPhiIdeal.class) { zero = 0; } } if (zero == 0) { arr = new int[8]; } else { int M = 4; for (int i = 0; i < M; i++) { boolean flag2 = _mutatorFlip(); boolean flag3 = _mutatorFlip(); if (flag2) { break; } } } } public static void main(String[] args) { TestNodeWithNoUseAfterPhiIdeal t = new TestNodeWithNoUseAfterPhiIdeal(); for (int i = 0; i < 10_000; i++) { t.test(); } } }