/* * Copyright (c) 2018, Oracle and/or its affiliates. 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 8208275 * @summary Test removal of strip mined loop with only one iteration. * @run main/othervm -XX:-TieredCompilation -Xcomp * -XX:CompileCommand=compileonly,compiler.loopopts.TestOneIterationStripMined::test* * compiler.loopopts.TestOneIterationStripMined */ package compiler.loopopts; public class TestOneIterationStripMined { static int iField; static volatile Object oField; public static void test1(int val) { iField = 0; // Do something // This loop is strip mined and then removed because it has only one iteration. for (int i = 0; i < 1; ++i) { // Trigger split-if optimization if (val == 0) { break; } val = 0; } } // Same as test1 but with a volatile Object field // (will trigger a different failure mode) public static void test2(int val) { oField = null; for (int i = 0; i < 1; ++i) { if (val == 0) { break; } val = 0; } } // Same as test1 but without any code outside loop body // (will trigger a different failure mode) public static void test3(int val) { for (int i = 0; i < 1; ++i) { if (val == 0) { break; } val = 0; } } public static void main(String[] args) { test1(0); test2(0); test3(0); } }