8308504: C2: "malformed control flow" after JDK-8303466

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

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+/*
+ * Copyright (c) 2023, 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 8308504
+ * @summary With JDK-8303466 the unroll-limit became more precise, and does not overflow.
+ *          We must ensure that the type of the loop incr also does not overflow.
+ * @run main/othervm -Xcomp -XX:-TieredCompilation
+ *                   -XX:+UnlockDiagnosticVMOptions -XX:RepeatCompilation=100
+ *                   -XX:+StressIGVN
+ *                   -XX:CompileOnly=compiler.loopopts.TestLoopIncrNoOverflow::test
+ *                   compiler.loopopts.TestLoopIncrNoOverflow
+ */
+
+package compiler.loopopts;
+
+public class TestLoopIncrNoOverflow {
+    static int N;
+
+    static void test() {
+        int arr[] = new int[N];
+        short s = 1;
+        double d = 1.0;
+        for (int i = 49; i > 8; i--) {
+            for (int j = 7; j > i; j -= 3) {
+                if (i == 8) {
+                    s *= arr[1];
+                }
+                d = arr[j];
+            }
+        }
+        Double.doubleToLongBits(d);
+    }
+
+    public static void main(String[] strArr) {
+        for (int i = 0; i < 10_000; i++) {
+            test();
+        }
+    }
+}