--- a/c++lib/CMakeLists.txt
+++ b/c++lib/CMakeLists.txt
@@ -55,11 +55,9 @@ if(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX)
     message(STATUS "This version of g++ (${CMAKE_CXX_COMPILER_VERSION}) incorrectly warns about possibly uninitialised memory when using std::variant containing a std::shared_ptr. Disabling this warning.")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-maybe-uninitialized")
   endif()
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2")
 endif()
 
 if("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
-   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O2")
 endif()
 
 if(MSVC)