--- a/python/src/llvm.cc
+++ b/python/src/llvm.cc
@@ -629,11 +629,12 @@ void init_triton_llvm(py::module_ &m) {
       });
 
   // optimization levels
-  py::class_<llvm::OptimizationLevel>(m, "optimization_level");
-  m.attr("OPTIMIZE_O0") = llvm::OptimizationLevel::O0;
-  m.attr("OPTIMIZE_O1") = llvm::OptimizationLevel::O1;
-  m.attr("OPTIMIZE_O2") = llvm::OptimizationLevel::O2;
-  m.attr("OPTIMIZE_O3") = llvm::OptimizationLevel::O3;
+  py::enum_<llvm::OptimizationLevel>(m, "optimization_level")
+      .value("OPTIMIZE_O0", llvm::OptimizationLevel::O0)
+      .value("OPTIMIZE_O1", llvm::OptimizationLevel::O1)
+      .value("OPTIMIZE_O2", llvm::OptimizationLevel::O2)
+      .value("OPTIMIZE_O3", llvm::OptimizationLevel::O3)
+      .export_values();
 
   m.def(
       "to_module",