--- a/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/calc/NarrowNode.java	Fri Feb 02 10:37:48 2018 -0500
+++ b/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.nodes/src/org/graalvm/compiler/nodes/calc/NarrowNode.java	Fri Feb 02 17:28:17 2018 -0800
@@ -112,9 +112,9 @@
                     // ==> sxxx -(sign-extend)-> sssssxxx
                     return SignExtendNode.create(other.getValue(), other.getInputBits(), getResultBits(), view);
                 } else if (other instanceof ZeroExtendNode) {
-                    // xxxx -(zero-extend)-> 00000000 00000xxx -(narrow)-> 0000xxxx
+                    // xxxx -(zero-extend)-> 00000000 0000xxxx -(narrow)-> 0000xxxx
                     // ==> xxxx -(zero-extend)-> 0000xxxx
-                    return new ZeroExtendNode(other.getValue(), other.getInputBits(), getResultBits());
+                    return new ZeroExtendNode(other.getValue(), other.getInputBits(), getResultBits(), ((ZeroExtendNode) other).isInputAlwaysPositive());
                 }
             }
         } else if (forValue instanceof AndNode) {