1 /* 2 * Copyright (c) 2014, 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 8048170 27 * @summary Following range check smearing, range check cannot be replaced by dominating identical test. 28 * @run main/othervm -XX:-BackgroundCompilation -XX:-UseOnStackReplacement TestRangeCheckSmearingLoopOpts 29 * 30 */ 31 public class TestRangeCheckSmearingLoopOpts { 32 33 static int dummy; 34 35 static int m1(int[] array, int i) { 36 for (;;) { 37 for (;;) { 38 if (array[i] < 0) { // range check (i+0) dominates equivalent check below 39 break; 40 } 41 i++; 42 } 43 44 // A control flow that stops IfNode::up_one_dom() 45 if ((i % 2)== 0) { 46 if ((array[i] % 2) == 0) { 47 dummy = i; 48 } 49 } 50 51 // IfNode::Ideal will rewrite some range checks if Compile::allow_range_check_smearing 52 if (array[i-1] == 9) { // range check (i-1) unchanged 53 int res = array[i-3]; // range check (i-3) unchanged 54 res += array[i]; // range check (i+0) unchanged 55 res += array[i-2]; // removed redundant range check 56 // the previous access might be hoisted by 57 // PhaseIdealLoop::split_if_with_blocks_post because 58 // it appears to have the same guard, but it also 59 // depends on the previous guards 60 return res; 61 } 62 i++; 63 } 64 } 65 66 static public void main(String[] args) { 67 int[] array = { 0, 1, 2, -3, 4, 5, -2, 7, 8, 9, -1 }; 68 for (int i = 0; i < 20000; i++) { 69 m1(array, 0); 70 } 71 array[0] = -1; 72 try { 73 m1(array, 0); 74 } catch(ArrayIndexOutOfBoundsException aioobe) {} 75 } 76 }