1 /* 2 * Copyright (c) 2018, Red Hat, Inc. 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 * @test 26 * @bug 8214344 27 * @summary LoadVector from a known element of a stable array shouldn't attempt to constant fold 28 * @modules java.base/jdk.internal.vm.annotation 29 * 30 * @run main/bootclasspath/othervm -XX:-TieredCompilation -XX:-BackgroundCompilation -XX:-UseOnStackReplacement LoadVectorFromStableArray 31 * 32 */ 33 34 import jdk.internal.vm.annotation.Stable; 35 36 public class LoadVectorFromStableArray { 37 public static void main(String[] args) { 38 byte[] byte_array = new byte[100]; 39 for (int i = 0; i < 20_000; i++) { 40 test_helper(0, 0); 41 test_helper(42, 0); 42 test_helper2(0, 20, byte_array, byte_array); 43 } 44 for (int i = 0; i < 20_000; i++) { 45 test(20, true); 46 test(20, false); 47 } 48 } 49 50 static @Stable byte[] stable_array1 = new byte[100]; 51 static @Stable byte[] stable_array2 = new byte[100]; 52 53 private static void test(int stop, boolean flag) { 54 int start = 0; 55 byte[] byte_array1 = stable_array1; 56 byte[] byte_array2 = flag ? stable_array1 : stable_array2; 57 int k = 2; 58 for (; k < 4; k *= 2); 59 int i = test_helper(k, stop); 60 // Loop in this method is unrolled and vectorized, then, upper 61 // bound is found to be constant and small. A single iteration 62 // of the main loop is executed. That iteration attempts to 63 // load a vector element from the array at a constant offset. 64 test_helper2(start, i, byte_array1, byte_array2); 65 } 66 67 68 private static void test_helper2(int start, int stop, byte[] byte_array1, byte[] byte_array2) { 69 for (int j = start; j < stop; j++) { 70 byte b = byte_array1[j+3]; 71 byte_array2[j+3] = b; 72 } 73 } 74 75 private static int test_helper(int k, int stop) { 76 int i = 0; 77 if (k == 42) { 78 i = stop; 79 } else { 80 i = 5; 81 } 82 return i; 83 } 84 }