--- a/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/calc/AndNode.java	Thu Mar 13 15:41:24 2014 -0700
+++ b/graal/com.oracle.graal.nodes/src/com/oracle/graal/nodes/calc/AndNode.java	Tue Mar 18 09:48:59 2014 -0700
@@ -66,6 +66,14 @@
             if ((rawY & mask) == 0) {
                 return ConstantNode.forIntegerStamp(stamp(), 0, graph());
             }
+            if (x().stamp() instanceof IntegerStamp) {
+                IntegerStamp xStamp = (IntegerStamp) x().stamp();
+                if (((xStamp.upMask() | xStamp.downMask()) & ~rawY) == 0) {
+                    // No bits are set which are outside the mask, so the mask will have no effect.
+                    return x();
+                }
+            }
+
             return BinaryNode.reassociate(this, ValueNode.isConstantPredicate());
         }
         return this;