--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/graal/com.oracle.truffle.ruby.nodes/src/com/oracle/truffle/ruby/nodes/methods/arguments/ReadPreArgumentNode.java	Mon Jan 06 17:12:09 2014 +0000
@@ -0,0 +1,52 @@
+/*
+ * Copyright (c) 2013 Oracle and/or its affiliates. All rights reserved. This
+ * code is released under a tri EPL/GPL/LGPL license. You can use it,
+ * redistribute it and/or modify it under the terms of the:
+ *
+ * Eclipse Public License version 1.0
+ * GNU General Public License version 2
+ * GNU Lesser General Public License version 2.1
+ */
+package com.oracle.truffle.ruby.nodes.methods.arguments;
+
+import com.oracle.truffle.api.*;
+import com.oracle.truffle.api.frame.*;
+import com.oracle.truffle.api.nodes.*;
+import com.oracle.truffle.api.utilities.*;
+import com.oracle.truffle.ruby.nodes.*;
+import com.oracle.truffle.ruby.runtime.*;
+
+/**
+ * Read pre-optional argument.
+ */
+@NodeInfo(shortName = "read-pre-optional-argument")
+public class ReadPreArgumentNode extends RubyNode {
+
+    private final int index;
+    private final boolean undefinedIfNotPresent;
+
+    private final BranchProfile notPresentProfile = new BranchProfile();
+
+    public ReadPreArgumentNode(RubyContext context, SourceSection sourceSection, int index, boolean undefinedIfNotPresent) {
+        super(context, sourceSection);
+        this.index = index;
+        this.undefinedIfNotPresent = undefinedIfNotPresent;
+    }
+
+    @Override
+    public Object execute(VirtualFrame frame) {
+        final Object[] arguments = frame.getArguments(RubyArguments.class).getArguments();
+
+        if (undefinedIfNotPresent) {
+            if (index >= arguments.length) {
+                notPresentProfile.enter();
+                return UndefinedPlaceholder.INSTANCE;
+            }
+        } else {
+            assert index < arguments.length;
+        }
+
+        return arguments[index];
+    }
+
+}