--- /dev/null 2017-11-19 21:25:36.786560717 +0100 +++ new/test/hotspot/jtreg/compiler/unsafe/TestLoopUnswitching.java 2017-11-27 11:09:28.690648574 +0100 @@ -0,0 +1,102 @@ +/* + * Copyright (c) 2017, 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 8191887 + * @summary loop cloning misses support for Opaque4 node + * @modules java.base/jdk.internal.misc:+open + * + * @run main/othervm -XX:-BackgroundCompilation TestLoopUnswitching + * + */ + +import jdk.internal.misc.Unsafe; +import java.lang.reflect.Field; +import java.util.Arrays; + +public class TestLoopUnswitching { + + static final jdk.internal.misc.Unsafe UNSAFE = Unsafe.getUnsafe(); + static final long F_OFFSET; + + static class A { + int f; + A(int f) { + this.f = f; + } + } + + static { + try { + Field fField = A.class.getDeclaredField("f"); + F_OFFSET = UNSAFE.objectFieldOffset(fField); + } catch (Exception e) { + throw new RuntimeException(e); + } + } + + static int test1(A[] arr, boolean flag1, boolean flag2) { + int res = 0; + for (int i = 0; i < 10; i++) { + A a = arr[i]; + if (flag1) { // triggers unswitching + res += UNSAFE.getInt(a, F_OFFSET); + } + if (flag2) { + // Opaque4 node here is in the loop but If is out of the loop + res += UNSAFE.getInt(a, F_OFFSET); + break; + } + res += UNSAFE.getInt(a, F_OFFSET); + } + return res; + } + + static int test2(A[] arr, boolean flag1, boolean flag2) { + int res = 0; + for (int i = 0; i < 10; i++) { + A a = arr[i]; + if (flag1) { // triggers unswitching + res += UNSAFE.getInt(a, F_OFFSET); + } + if (flag2) { + // Opaque4 node here is out of the loop but Bool is in the the loop + res += UNSAFE.getInt(a, F_OFFSET); + break; + } + res += a.f; + } + return res; + } + + static public void main(String[] args) { + A[] arr = new A[1000]; + Arrays.fill(arr, new A(0x42)); + for (int i = 0; i < 20000; i++) { + test1(arr, (i%2) == 0, (i%2) == 0); + test2(arr, (i%2) == 0, (i%2) == 0); + } + } + +}