--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/Compiler/src/com/sun/c1x/opt/UnsafeCastEliminator.java	Wed Apr 27 11:43:22 2011 +0200
@@ -0,0 +1,76 @@
+/*
+ * Copyright (c) 2010, 2011, 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.
+ */
+package com.sun.c1x.opt;
+
+import com.sun.c1x.graph.*;
+import com.sun.c1x.ir.*;
+import com.sun.c1x.value.*;
+
+/**
+ * A mechanism to remove {@linkplain UnsafeCast#redundant redundant} unsafe casts.
+ *
+ * @author Doug Simon
+ */
+public class UnsafeCastEliminator implements ValueClosure, BlockClosure {
+
+    final IR ir;
+
+    /**
+     * Eliminates redundant unsafe casts from a given IR.
+     */
+    public UnsafeCastEliminator(IR ir) {
+        this.ir = ir;
+        ir.startBlock.iterateAnyOrder(this, false);
+    }
+
+    public void apply(BlockBegin block) {
+        if (block.isExceptionEntry()) {
+            for (FrameState ehState : block.exceptionHandlerStates()) {
+                ehState.valuesDo(this);
+            }
+        }
+
+        Instruction i = block;
+        while (i != null) {
+            FrameState stateBefore = i.stateBefore();
+            if (stateBefore != null) {
+                stateBefore.valuesDo(this);
+            }
+            i.inputValuesDo(this);
+            FrameState stateAfter = i.stateAfter();
+            if (stateAfter != null) {
+                stateAfter.valuesDo(this);
+            }
+            i = i.next();
+        }
+    }
+
+    public Value apply(Value i) {
+        if (i instanceof UnsafeCast) {
+            Value y = ((UnsafeCast) i).nonRedundantReplacement();
+            assert y != null;
+            return y;
+        }
+        return i;
+    }
+}