8260608: add a regression test for 8260370

Reviewed-by: kvn

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

@@ -0,0 +1,75 @@
+/*
+ * 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
+ * @bug 8260370
+ * @summary C2: LoopLimit node is not eliminated
+ *
+ * @run main/othervm
+ *      -Xcomp
+ *      -XX:CompileOnly=compiler/loopopts/TestLoopLimitNodeElimination
+ *      compiler.loopopts.TestLoopLimitNodeElimination
+ */
+
+package compiler.loopopts;
+
+// the test code is derived from a randomly generated test
+public class TestLoopLimitNodeElimination {
+    private static class MyException extends RuntimeException { }
+    private static final int ITERATIONS = 100000;
+    private static final int SIZE = 400;
+
+    private static int counter = 0;
+
+    int[] array1 = new int[SIZE];
+
+    void test() {
+        int[] array2 = new int[SIZE];
+        array1[2] = 0;
+        array1 = array1;
+        for (long i = 301; i > 2; i -= 2) {
+            int j = 1;
+            do {
+               for (int k = (int) i; k < 1; k++) { }
+            } while (++j < 4);
+        }
+
+        counter++;
+        if (counter == ITERATIONS) {
+            throw new MyException();
+        }
+    }
+
+    public static void main(String[] args) {
+        try {
+            var test = new TestLoopLimitNodeElimination();
+            while (true) {
+                test.test();
+            }
+        } catch (MyException e) {
+            // expected
+        }
+    }
+}
+