/* * Copyright (c) 2021, 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 * @key stress randomness * @bug 8274074 * @requires vm.compiler2.enabled * @summary Sinking a data node used as divisor of a DivI node into a zero check UCT loses its pin outside the loop due to * optimizing the CastII node away, resulting in a div by zero crash (SIGFPE) due to letting the DivI node floating * back inside the loop. * @run main/othervm -Xcomp -XX:CompileCommand=compileonly,compiler.loopopts.TestSinkingDivisorLostPin::* -XX:-TieredCompilation * -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM -XX:StressSeed=4177789702 compiler.loopopts.TestSinkingDivisorLostPin * @run main/othervm -Xcomp -XX:CompileCommand=compileonly,compiler.loopopts.TestSinkingDivisorLostPin::* -XX:-TieredCompilation * -XX:+UnlockDiagnosticVMOptions -XX:+StressGCM compiler.loopopts.TestSinkingDivisorLostPin */ package compiler.loopopts; public class TestSinkingDivisorLostPin { static int iFld = 1; static int x = 1; static int q = 0; static int iArrFld[] = new int[100]; public static void main(String[] strArr) { test(); } static void test() { int y = 1; int i = 1; do { int j; for (j = 1; j < 88; j++) { iArrFld[1] = x; } try { y = iFld - q; // y = 1 - 0 y = (iArrFld[2] / y); // y = iArrFld[2] / 1 // Zero check Z1 with UCT // DivI node D on IfTrue path of zero check y = (5 / iFld); // y = 5 / 1 // Zero check Z2 with UCT // DivI node D is only used on IfFalse path of zero check Z2 into UCT (on IfTrue path, the result is not used anywhere // because we directly overwrite it again with "y = (5 / iFld)). The IfFalse path of the zero check, however, is never // taken because iFld = 1. But before applying the sinking algorithm, the DivI node D could be executed during the // loop, as the zero check Z1 succeeds. Only after sinking the SubI node for "iFld - q" into the IfFalse path of Z2 // and optimizing it accordingly (iFld is found to be zero because the zero check Z2 failed, i.e. iFld is zero which is // propagated into the CastII node whose type is improved to [0,0] and the node is replaced by constant zero), the // DivI node must NOT be executed inside the loop anymore. But the DivI node is executed in the loop because of losing // the CastII pin. The fix is to update the control input of the DivI node to the get_ctrl() input outside the loop // (IfFalse of zero check Z2). } catch (ArithmeticException a_e) { } iFld -= 8; if (y == 3) { } i++; } while (i < 10); } }