6816548: Uninitialized register when performing casting + auto(un)boxing

Summary: Constant value of final variable is lost during lowering
Reviewed-by: jjg

src/share/classes/com/sun/tools/javac/comp/Lower.java

@@ -2631,8 +2631,8 @@ public class Lower extends TreeTranslator {
         if (havePrimitive) {
             Type unboxedTarget = types.unboxedType(type);
             if (unboxedTarget.tag != NONE) {
-                if (!types.isSubtype(tree.type, unboxedTarget))
-                    tree.type = unboxedTarget; // e.g. Character c = 89;
+                if (!types.isSubtype(tree.type, unboxedTarget)) //e.g. Character c = 89;
+                    tree.type = unboxedTarget.constType(tree.type.constValue());
                 return (T)boxPrimitive((JCExpression)tree, type);
             } else {
                 tree = (T)boxPrimitive((JCExpression)tree);

test/tools/javac/boxing/T6816548.java

+/*
+ * Copyright 2009 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+
+/*
+ * @test
+ * @bug     6816548
+ * @summary Uninitialized register when performing casting + auto(un)boxing
+ * @author  mcimadamore
+ */
+public class T6816548 {
+
+    public static void main(String[] args) {
+        testInt();
+        testShort();
+        testByte();
+        testChar();
+    }
+
+    public static void testInt() {
+        final int fi = 0;
+        Byte b = fi;
+        Short s = fi;
+        Character c = fi;
+    }
+
+    public static void testShort() {
+        final short fs = 0;
+        Byte b = fs;
+        Short s = fs;
+        Character c = fs;
+    }
+
+    public static void testByte() {
+        final byte fb = 0;
+        Byte b = fb;
+        Short s = fb;
+        Character c = fb;
+    }
+
+    public static void testChar() {
+        final char fc = '0';
+        Byte b = fc;
+        Short s = fc;
+        Character c = fc;
+    }
+}