8373525: C2: assert(_base == Long) failed: Not a Long

Reviewed-by: chagedorn, mhaessig

src/hotspot/share/opto/addnode.cpp

@@ -1529,8 +1529,10 @@ static Node* fold_subI_no_underflow_pattern(Node* n, PhaseGVN* phase) {
         Node* x    = add2->in(1);
         Node* con2 = add2->in(2);
         if (is_sub_con(con2)) {
+          // The graph could be dying (i.e. x is top) in which case type(x) is not a long.
+          const TypeLong* x_long = phase->type(x)->isa_long();
           // Collapsed graph not equivalent if potential over/underflow -> bailing out (*)
-          if (can_overflow(phase->type(x)->is_long(), con1->get_long() + con2->get_long())) {
+          if (x_long == nullptr || can_overflow(x_long, con1->get_long() + con2->get_long())) {
             return nullptr;
           }
           Node* new_con = phase->transform(new AddLNode(con1, con2));

test/hotspot/jtreg/compiler/loopopts/TestValidTypeInOverflowProtection.java

@@ -0,0 +1,114 @@
+/*
+ * 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 8373525
+ * @summary Test for the check of a valid type (long) for the input variable of overflow protection
+ * @run main/othervm -Xbatch -XX:-TieredCompilation -XX:CompileCommand=compileonly,compiler.loopopts.TestValidTypeInOverflowProtection::test
+ *                   ${test.main.class}
+ * @run main ${test.main.class}
+ */
+
+package compiler.loopopts;
+
+import java.util.Vector;
+
+class TestVector extends Vector {
+    TestVector(int initialCapacity) {
+        super(initialCapacity);
+    }
+
+    Object getElementData() {
+        return elementData;
+    }
+}
+
+public class TestValidTypeInOverflowProtection {
+    int cntr;
+    int mode;
+    int value = 533;
+    int one = 1;
+
+    public static void main(String[] args) {
+        TestValidTypeInOverflowProtection test = new TestValidTypeInOverflowProtection();
+        for (int i = 0; i < 1000; i++) {
+            test.test();
+        }
+    }
+
+    TestVector nextVector() {
+        if (cntr == one) {
+            return null;
+        }
+        TestVector vect = new TestVector(value);
+        if (mode == 2) {
+            int cap = vect.capacity();
+            for (int i = 0; i < cap; i++) {
+                vect.addElement(new Object());
+            }
+        }
+        if (++mode == 3) {
+            mode = cntr++;
+        }
+        return vect;
+    }
+
+    String test() {
+        cntr = 0;
+        TestVector vect = nextVector();
+        while (vect != null) {
+            Object backup_array = new Object[vect.size()];
+            System.arraycopy(vect.getElementData(), 0, backup_array, 0, vect.size());
+            int old_size = vect.size();
+            int old_cap = vect.capacity();
+            vect.setSize(vect.capacity() + 1);
+            for (int i = old_size; i < old_cap; i++) {
+                if (vect.elementAt(i) != null) {
+                }
+            }
+            for (int i = 0; i < new MyInteger(old_size).v; i++) {
+            }
+            vect = nextVector();
+        }
+        return null;
+    }
+
+    class MyInteger {
+        int v;
+
+        MyInteger(int v) {
+            int M452 = 4;
+            int N452 = 8;
+            for (int i452 = 0; i452 < M452; i452++) {
+                for (int j452 = 0; j452 < N452; j452++) {
+                    switch (i452) {
+                        case -2:
+                        case 0:
+                            this.v = v;
+                    }
+                }
+            }
+        }
+    }
+}