--- a/graal/com.oracle.graal.compiler.common/src/com/oracle/graal/compiler/common/type/StampFactory.java	Thu Mar 05 14:26:16 2015 +0100
+++ b/graal/com.oracle.graal.compiler.common/src/com/oracle/graal/compiler/common/type/StampFactory.java	Sun Mar 08 21:58:34 2015 +0100
@@ -37,6 +37,8 @@
     private static final Stamp objectAlwaysNullStamp = new ObjectStamp(null, false, false, true);
     private static final Stamp nodeIntrinsicStamp = new ObjectStamp(null, false, false, false);
     private static final Stamp positiveInt = forInteger(Kind.Int, 0, Integer.MAX_VALUE, 0, Integer.MAX_VALUE);
+    private static final Stamp booleanTrue = forInteger(Kind.Boolean, -1, -1, 1, 1);
+    private static final Stamp booleanFalse = forInteger(Kind.Boolean, 0, 0, 0, 0);
 
     private static void setCache(Kind kind, Stamp stamp) {
         stampCache[kind.ordinal()] = stamp;
@@ -80,6 +82,14 @@
         }
     }
 
+    public static Stamp tautology() {
+        return booleanTrue;
+    }
+
+    public static Stamp contradiction() {
+        return booleanFalse;
+    }
+
     /**
      * Return a stamp for a Java kind, as it would be represented on the bytecode stack.
      */