diff test/compiler/loopopts/TestDeadBackbranchArrayAccess.java @ 20680:5b8e0f84f00f

8054478: C2: Incorrectly compiled char[] array access crashes JVM Summary: dead backbranch in main loop results in erroneous array access Reviewed-by: kvn, iveresov
author roland
date Mon, 01 Dec 2014 22:27:00 +0100
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/compiler/loopopts/TestDeadBackbranchArrayAccess.java	Mon Dec 01 22:27:00 2014 +0100
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+/*
+ * Copyright (c) 2014, 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 8054478
+ * @summary dead backbranch in main loop results in erroneous array access
+ * @run main/othervm -XX:CompileOnly=TestDeadBackbranchArrayAccess -Xcomp TestDeadBackbranchArrayAccess
+ *
+ */
+
+public class TestDeadBackbranchArrayAccess {
+    static char[] pattern0 = {0};
+    static char[] pattern1 = {1};
+
+    static void test(char[] array) {
+        if (pattern1 == null) return;
+
+        int i = 0;
+        int pos = 0;
+        char c = array[pos];
+
+        while (i >= 0 && (c == pattern0[i] || c == pattern1[i])) {
+            i--;
+            pos--;
+            if (pos != -1) {
+                c = array[pos];
+            }
+        }
+    }
+
+    public static void main(String[] args) {
+        for (int i = 0; i < 1000000; i++) {
+            test(new char[1]);
+        }
+    }
+}