/* * Copyright (c) 2020, 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 8248552 * @summary A Division/modulo node whose zero check was removed is split through an induction variable phi and executed before * the loop limit check resulting in a SIGFPE because the divisor is zero. * * @run main/othervm -XX:CompileCommand=dontinline,compiler.c2.loopopts.TestSplitThruPhiDivMod::test* compiler.c2.loopopts.TestSplitThruPhiDivMod */ package compiler.c2.loopopts; public class TestSplitThruPhiDivMod { int x; public int testMod() { int i1 = 2; for (int i = 5; i < 25; i++) { for (int j = 50; j > 1; j -= 2) { /* * Zero check is removed based on the type of the induction variable phi (variable j) since its always between 1 and 50. * However, when splitting the modulo node through the phi, it can be executed right after the subtraction j-2 which can be * 0 before evaluation the loop limit condition in the last iteration when j is 2: j-2 = 2-2 = 0. This results in a SIGFPE. * The fix is to not split a division or modulo node 'n' through the induction variable phi if the zero check was removed * earlier and the new inputs of the clones of 'n' after the split could be zero (i.e. the type of the clones of 'n' include 0). */ x = (20 % j); // Problematic division as part of modulo. Results in a SIGFPE, even though j is always non-zero. i1 = (i1 / i); for (int k = 3; k > 1; k--) { switch ((i % 4) + 22) { case 22: switch (j % 10) { case 83: x += 5; break; } } } } } return i1; } public int testDiv() { int i1 = 2; for (int i = 5; i < 25; i++) { for (int j = 50; j > 1; j -= 2) { // Same issue as above but with a division node. See explanation above. x = (20 / j); // Problematic division. Results in a SIGFPE, even though j is always non-zero. i1 = (i1 / i); for (int k = 3; k > 1; k--) { switch ((i % 4) + 22) { case 22: switch (j % 10) { case 83: x += 5; break; } } } } } return i1; } public static void main(String[] strArr) { TestSplitThruPhiDivMod t = new TestSplitThruPhiDivMod(); for (int i = 0; i < 10000; i++) { t.testDiv(); t.testMod(); } } }