--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/truffle/com.oracle.truffle.dsl.processor/src/com/oracle/truffle/dsl/processor/model/GuardExpression.java	Wed Jun 17 10:58:08 2015 +0200
@@ -0,0 +1,86 @@
+/*
+ * Copyright (c) 2012, 2012, 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.oracle.truffle.dsl.processor.model;
+
+import java.util.*;
+
+import javax.lang.model.element.*;
+
+import com.oracle.truffle.dsl.processor.expression.*;
+import com.oracle.truffle.dsl.processor.expression.DSLExpression.Negate;
+import com.oracle.truffle.dsl.processor.java.*;
+
+public final class GuardExpression extends MessageContainer {
+
+    private final TemplateMethod source;
+    private final DSLExpression expression;
+
+    public GuardExpression(TemplateMethod source, DSLExpression expression) {
+        this.source = source;
+        this.expression = expression;
+    }
+
+    @Override
+    public Element getMessageElement() {
+        return source.getMessageElement();
+    }
+
+    @Override
+    public AnnotationMirror getMessageAnnotation() {
+        return source.getMessageAnnotation();
+    }
+
+    @Override
+    public AnnotationValue getMessageAnnotationValue() {
+        return ElementUtils.getAnnotationValue(getMessageAnnotation(), "guards");
+    }
+
+    public DSLExpression getExpression() {
+        return expression;
+    }
+
+    public boolean equalsNegated(GuardExpression other) {
+        boolean negated = false;
+        DSLExpression thisExpression = expression;
+        if (thisExpression instanceof Negate) {
+            negated = true;
+            thisExpression = ((Negate) thisExpression).getReceiver();
+        }
+
+        boolean otherNegated = false;
+        DSLExpression otherExpression = other.expression;
+        if (otherExpression instanceof Negate) {
+            otherNegated = true;
+            otherExpression = ((Negate) otherExpression).getReceiver();
+        }
+        return Objects.equals(thisExpression, otherExpression) && negated != otherNegated;
+    }
+
+    public boolean implies(GuardExpression other) {
+        if (Objects.equals(expression, other.expression)) {
+            return true;
+        }
+        return false;
+    }
+
+}