| /* |
| * Copyright (c) 2016, 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 8159016 8202949 8203915 |
| * @summary Tests correct dominator information after over-unrolling a loop. |
| * @requires vm.gc == "Parallel" | vm.gc == "null" |
| * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions |
| * -Xcomp -XX:-TieredCompilation -XX:-UseSwitchProfiling |
| * -XX:-UseCountedLoopSafepoints -XX:LoopUnrollLimit=250 |
| * -XX:-UseG1GC -XX:+UseParallelGC compiler.loopopts.TestOverunrolling |
| */ |
| |
| package compiler.loopopts; |
| |
| public class TestOverunrolling { |
| |
| public static Object test1(int arg) { |
| Object arr[] = new Object[3]; |
| int lim = (arg & 3); |
| // The pre loop is executed for one iteration, initializing p[0]. |
| // The main loop is unrolled twice, initializing p[1], p[2], p[3] and p[4]. |
| // The p[3] and p[4] stores are always out of bounds and removed. However, |
| // C2 is unable to remove the "over-unrolled", dead main loop. As a result, |
| // there is a control path from the main loop to the post loop without a |
| // memory path (because the last store was replaced by TOP). We crash |
| // because we use a memory edge from a non-dominating region. |
| for (int i = 0; i < lim; ++i) { |
| arr[i] = new Object(); |
| } |
| // Avoid EA |
| return arr; |
| } |
| |
| public static long lFld = 0; |
| public static volatile double dFld = 0; |
| |
| public static void test2() { |
| int iArr[] = new int[10]; |
| // The inner for-loop is overunrolled because we fail to determine |
| // the constant lower and upper bound (6,8]. After unrolling multiple times, |
| // the range check dependent CastII/ConvI2L emitted for the iArr access become |
| // TOP because index 'j' is out of bounds. As a result, the memory graph is |
| // corrupted with memory consuming nodes still being reachable because the dead |
| // loop is not (yet) removed (Opaque1 nodes are still guarding the bounds). |
| for (int i = 6; i < 10; i++) { |
| for (int j = 8; j > i; j--) { |
| int k = 1; |
| do { |
| iArr[j] = 0; |
| switch (k) { |
| case 1: |
| lFld = 0; |
| break; |
| case 10: |
| dFld = 0; |
| break; |
| } |
| } while (++k < 1); |
| } |
| } |
| } |
| |
| // Similar to test2 but we cannot statically determine the upper bound of |
| // the inner for loop and can therefore not prevent over-unrolling. |
| public static void test3(int[] array) { |
| int[] iArr = new int[8]; |
| for (int i = 0; i < array.length; i++) { |
| for (int j = 5; j < i; j++) { |
| int k = 1; |
| do { |
| iArr[j] = 0; |
| switch (k) { |
| case 1: |
| lFld = 0; |
| break; |
| case 10: |
| dFld = 0; |
| break; |
| } |
| } while (++k < 1); |
| } |
| } |
| } |
| |
| // Similar to test3 but with negative stride and constant outer loop limit |
| public static void test4(int[] array, boolean store) { |
| int[] iArr = new int[8]; |
| for (int i = -8; i < 8; i++) { |
| for (int j = 5; j > i; j--) { |
| int k = 1; |
| do { |
| if (store) { |
| iArr[j] = 0; |
| } |
| switch (k) { |
| case 1: |
| lFld = 0; |
| break; |
| case 10: |
| dFld = 0; |
| break; |
| } |
| } while (++k < 1); |
| } |
| } |
| } |
| |
| // The inner for-loop is over-unrolled and vectorized resulting in |
| // a crash in the matcher because the memory input to a vector is top. |
| public static int test5(int[] array) { |
| int result = 0; |
| int[] iArr = new int[8]; |
| for (int i = 0; i < array.length; i++) { |
| for (int j = 5; j < i; j++) { |
| iArr[j] += array[j]; |
| result += array[j]; |
| } |
| } |
| return result; |
| } |
| |
| public static void main(String args[]) { |
| for (int i = 0; i < 42; ++i) { |
| test1(i); |
| } |
| test2(); |
| int[] array = new int[8]; |
| test3(array); |
| test4(array, false); |
| test5(array); |
| } |
| } |
| |