1 /* 2 * Copyright (c) 2015, Oracle and/or its affiliates. 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 8078262 27 * @summary Tests correct dominator information after loop peeling. 28 * @run main/othervm -Xcomp -XX:CompileCommand=compileonly,TestLoopPeeling::test TestLoopPeeling 29 */ 30 public class TestLoopPeeling { 31 32 public int[] array = new int[100]; 33 34 public static void main(String args[]) { 35 new TestLoopPeeling().test(0, 1); 36 } 37 38 public void test(int index, int inc) { 39 int storeIndex = -1; 40 41 for (; index < 10; index += inc) { 42 // This loop invariant check triggers loop peeling because it can 43 // be moved out of the loop (see 'IdealLoopTree::policy_peeling'). 44 if (inc == 42) return; 45 46 // This loop variant usage of LShiftL( ConvI2L( Phi(storeIndex) ) ) 47 // prevents the split if optimization that would otherwise clone the 48 // LShiftL and ConvI2L nodes and assign them to their corresponding array 49 // address computation (see 'PhaseIdealLoop::split_if_with_blocks_post'). 50 if (storeIndex > 0 && array[storeIndex] == 42) return; 51 52 if (index == 42) { 53 // This store and the corresponding range check are moved out of the 54 // loop and both used after old loop and the peeled iteration exit. 55 // For the peeled iteration, storeIndex is always -1 and the ConvI2L 56 // is replaced by TOP. However, the range check is not folded because 57 // we don't do the split if optimization in PhaseIdealLoop2. 58 // As a result, we have a (dead) control path from the peeled iteration 59 // to the StoreI but the data path is removed. 60 array[storeIndex] = 1; 61 return; 62 } 63 64 storeIndex++; 65 } 66 67 // Second store to 'array' 68 //array[storeIndex] = 1; 69 } 70 }