diff --git a/src/hotspot/share/opto/divnode.cpp b/src/hotspot/share/opto/divnode.cpp index db4fedbba3b..ed72d8a11cf 100644 --- a/src/hotspot/share/opto/divnode.cpp +++ b/src/hotspot/share/opto/divnode.cpp @@ -1112,8 +1112,6 @@ Node *ModINode::Ideal(PhaseGVN *phase, bool can_reshape) { if( !ti->is_con() ) return nullptr; jint con = ti->get_con(); - Node *hook = new Node(1); - // First, special check for modulo 2^k-1 if( con >= 0 && con < max_jint && is_power_of_2(con+1) ) { uint k = exact_log2(con+1); // Extract k @@ -1129,7 +1127,9 @@ Node *ModINode::Ideal(PhaseGVN *phase, bool can_reshape) { Node *x = in(1); // Value being mod'd Node *divisor = in(2); // Also is mask - hook->init_req(0, x); // Add a use to x to prevent him from dying + // Add a use to x to prevent it from dying + Node* hook = new Node(1); + hook->init_req(0, x); // Generate code to reduce X rapidly to nearly 2^k-1. for( int i = 0; i < trip_count; i++ ) { Node *xl = phase->transform( new AndINode(x,divisor) ); @@ -1185,6 +1185,7 @@ Node *ModINode::Ideal(PhaseGVN *phase, bool can_reshape) { } // Save in(1) so that it cannot be changed or deleted + Node* hook = new Node(1); hook->init_req(0, in(1)); // Divide using the transform from DivI to MulL @@ -1407,8 +1408,6 @@ Node *ModLNode::Ideal(PhaseGVN *phase, bool can_reshape) { if( !tl->is_con() ) return nullptr; jlong con = tl->get_con(); - Node *hook = new Node(1); - // Expand mod if(con >= 0 && con < max_jlong && is_power_of_2(con + 1)) { uint k = log2i_exact(con + 1); // Extract k @@ -1426,13 +1425,15 @@ Node *ModLNode::Ideal(PhaseGVN *phase, bool can_reshape) { Node *x = in(1); // Value being mod'd Node *divisor = in(2); // Also is mask - hook->init_req(0, x); // Add a use to x to prevent him from dying + // Add a use to x to prevent it from dying + Node* hook = new Node(1); + hook->init_req(0, x); // Generate code to reduce X rapidly to nearly 2^k-1. for( int i = 0; i < trip_count; i++ ) { Node *xl = phase->transform( new AndLNode(x,divisor) ); Node *xh = phase->transform( new RShiftLNode(x,phase->intcon(k)) ); // Must be signed x = phase->transform( new AddLNode(xh,xl) ); - hook->set_req(0, x); // Add a use to x to prevent him from dying + hook->set_req(0, x); // Add a use to x to prevent it from dying } // Generate sign-fixup code. Was original value positive? @@ -1482,6 +1483,8 @@ Node *ModLNode::Ideal(PhaseGVN *phase, bool can_reshape) { } // Save in(1) so that it cannot be changed or deleted + // Add a use to x to prevent him from dying + Node* hook = new Node(1); hook->init_req(0, in(1)); // Divide using the transform from DivL to MulL diff --git a/test/hotspot/jtreg/compiler/c2/igvn/TestModIdealCreatesUselessNode.java b/test/hotspot/jtreg/compiler/c2/igvn/TestModIdealCreatesUselessNode.java new file mode 100644 index 00000000000..4d70ee92a92 --- /dev/null +++ b/test/hotspot/jtreg/compiler/c2/igvn/TestModIdealCreatesUselessNode.java @@ -0,0 +1,56 @@ +/* + * Copyright (c) 2025, 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. + */ + +package compiler.c2.igvn; + +/* + * @test + * @bug 8372302 + * @summary ModINode::Ideal and ModLNode::Ideal use an intermediate "hook" node + * to keep stuff alive between phase->transform(...) calls. In some cases, + * this node is not properly deleted before returning, causing failure + * in the verification because the node count has changed. This test + * ensures that the intermediate node gets destroyed before returning. + * @run main/othervm -XX:+IgnoreUnrecognizedVMOptions -XX:+UnlockDiagnosticVMOptions + * -Xcomp -XX:-TieredCompilation + * -XX:CompileCommand=compileonly,${test.main.class}::test* + * -XX:VerifyIterativeGVN=1110 + * ${test.main.class} + * @run main ${test.main.class} + * + */ + +public class TestModIdealCreatesUselessNode { + static int test0(int x) { + return x % Integer.MIN_VALUE; + } + + static long test1(long x) { + return x % Long.MIN_VALUE; + } + + public static void main(String[] args) { + test0(0); + test1(0L); + } +}