8351660: C2: SIGFPE in unsigned_mod_value

Co-authored-by: Emanuel Peter <[email protected]>
Reviewed-by: chagedorn, dfenacci, epeter

Author: 2 people

src/hotspot/share/opto/divnode.cpp

@@ -1319,6 +1319,11 @@ static const Type* unsigned_mod_value(PhaseGVN* phase, const Node* mod) {
     return TypeClass::ZERO;
   }
 
+  // Mod by zero?  Throw an exception at runtime!
+  if (type_divisor->is_con() && type_divisor->get_con() == 0) {
+    return TypeClass::POS;
+  }
+
   const TypeClass* type_dividend = t1->cast<TypeClass>();
   if (type_dividend->is_con() && type_divisor->is_con()) {
     Unsigned dividend = static_cast<Unsigned>(type_dividend->get_con());

test/hotspot/jtreg/compiler/integerArithmetic/TestUnsignedModByZero.java

@@ -0,0 +1,58 @@
+/*
+ * 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.
+ */
+
+/*
+ * @test
+ * @bug 8351660
+ * @summary Test that modulo by zero throws an exception at runtime in case of unsigned values.
+ * @library /test/lib
+ * @run main/othervm -Xbatch
+ *                   -XX:CompileCommand=compileonly,compiler.integerArithmetic.TestUnsignedModByZero::testInt
+ *                   -XX:CompileCommand=compileonly,compiler.integerArithmetic.TestUnsignedModByZero::testLong
+ *                   compiler.integerArithmetic.TestUnsignedModByZero
+ */
+
+ package compiler.integerArithmetic;
+
+ import jdk.test.lib.Asserts;
+
+
+ public class TestUnsignedModByZero {
+
+     public static Object testInt() {
+        double x = 1.0;
+        return Integer.remainderUnsigned(1, (int)(x % x));
+    }
+
+     public static Object testLong() {
+        double x = 1.0;
+        return Long.remainderUnsigned(1, (long)(x % x));
+    }
+
+     public static void main(String[] args) {
+        for (int i = 0; i < 10_000; i++) {
+             Asserts.assertThrows(ArithmeticException.class, TestUnsignedModByZero::testInt);
+             Asserts.assertThrows(ArithmeticException.class, TestUnsignedModByZero::testLong);
+        }
+     }
+ }