diff --git a/src/sat/sat_aig_finder.cpp b/src/sat/sat_aig_finder.cpp
index 6318d18c0..2d1904857 100644
--- a/src/sat/sat_aig_finder.cpp
+++ b/src/sat/sat_aig_finder.cpp
@@ -112,7 +112,7 @@ namespace sat {
             }
             binary():x(null_literal), y(null_literal), use_list(nullptr) {}
             struct hash {
-                unsigned operator()(binary const& t) const { return t.x.hash() + 2* t.y.hash(); }
+                unsigned operator()(binary const& t) const { return mk_mix(t.x.index(), t.y.index(), 3); }
             };
             struct eq {
                 bool operator()(binary const& a, binary const& b) const {