diff --git a/src/util.cpp b/src/util.cpp
index 25f07f08e3..31de5bfac0 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -41,7 +41,7 @@ setTreeNodeValue(Thread* t, object n, object value)
 inline bool
 treeNodeRed(Thread*, object n)
 {
-  return (cast<intptr_t>(n, TreeNodeValue) & (~PointerMask)) != 1;
+  return (cast<intptr_t>(n, TreeNodeValue) & (~PointerMask)) == 1;
 }
 
 inline void