diff --git a/src/libslic3r/TreeSupport.hpp b/src/libslic3r/TreeSupport.hpp
index b5f25a507..e799fba67 100644
--- a/src/libslic3r/TreeSupport.hpp
+++ b/src/libslic3r/TreeSupport.hpp
@@ -170,7 +170,7 @@ public:
 struct LineHash {
     size_t operator()(const Line& line) const {
         return (std::hash<coord_t>()(line.a(0)) ^ std::hash<coord_t>()(line.b(1))) * 102 +
-            (std::hash<coord_t>()(line.a(0)) ^ std::hash<coord_t>()(line.b(1))) * 10222;
+            (std::hash<coord_t>()(line.a(1)) ^ std::hash<coord_t>()(line.b(0))) * 10222;
     }
 };