diff --git a/src/constraint_solver/expr_array.cc b/src/constraint_solver/expr_array.cc
index b98595f386..c6255da081 100644
--- a/src/constraint_solver/expr_array.cc
+++ b/src/constraint_solver/expr_array.cc
@@ -2320,10 +2320,14 @@ IntExpr* Solver::MakeSum(const std::vector<IntVar*>& vars) {
           new_max = CapAdd(vars[i]->Max(), new_max);
         }
       }
-      const string name =
+      const bool all_booleans = AreAllBooleans(vars.data(), vars.size());
+
+      const string name = all_booleans ?
+          StringPrintf("BooleanSum([%s])",
+                       DebugStringVector(vars, ", ").c_str()) :
           StringPrintf("Sum([%s])", DebugStringVector(vars, ", ").c_str());
       IntVar* const sum_var = MakeIntVar(new_min, new_max, name);
-      if (AreAllBooleans(vars.data(), vars.size())) {
+      if (all_booleans) {
         AddConstraint(RevAlloc(
             new SumBooleanEqualToVar(this, vars.data(), vars.size(), sum_var)));
       } else  if (new_min != kint64min && new_max != kint64max) {
diff --git a/src/constraint_solver/range_cst.cc b/src/constraint_solver/range_cst.cc
index 9c3ef9404e..dc5e7a80ff 100644
--- a/src/constraint_solver/range_cst.cc
+++ b/src/constraint_solver/range_cst.cc
@@ -1002,7 +1002,7 @@ Constraint* Solver::MakeIsLessOrEqualCt(
   } else if (right->Bound()) {
     return MakeIsLessOrEqualCstCt(left->Var(), right->Min(), b);
   }
-  return MakeIsLessOrEqualCstCt(MakeDifference(left, right)->Var(), 0, b);
+  return RevAlloc(new IsLessOrEqualCt(this, left->Var(), right->Var(), b));
 }
 
 IntVar* Solver::MakeIsLessVar(
@@ -1054,7 +1054,7 @@ Constraint* Solver::MakeIsLessCt(
   } else if (right->Bound()) {
     return MakeIsLessCstCt(left->Var(), right->Min(), b);
   }
-  return MakeIsLessCstCt(MakeDifference(left, right)->Var(), 0, b);
+  return RevAlloc(new IsLessCt(this, left->Var(), right->Var(), b));
 }
 
 IntVar* Solver::MakeIsGreaterOrEqualVar(