--- /dev/null	2015-09-18 08:01:11.771996015 +0200
+++ new/test/compiler/stringopts/TestPresizedStringBuilder.java	2015-09-18 12:58:32.293469248 +0200
@@ -0,0 +1,47 @@
+/*
+ * Copyright (c) 2015, 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 8136469
+ * @summary C2's string concatenation optimization fails with pre-sized StringBuilder
+ * @run main/othervm -XX:CompileCommand=dontinline,TestPresizedStringBuilder::test TestPresizedStringBuilder
+ */
+public class TestPresizedStringBuilder {
+
+  static final boolean count;
+  static {
+    count = true;
+  }
+
+  public static void main(String[] args) {
+    for (int i = 0; i < 100_000; ++i) {
+      test();
+    }
+  }
+
+  public static String test() {
+    return new StringBuilder(count ? 1 : 2).toString();
+  }
+}
+