diff --git a/CMakeLists.txt b/CMakeLists.txt
index cfadbcb3..e10d0ace 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,9 +21,7 @@ if(NOT ${PREBUILD_RESULT} EQUAL 0)
     message(FATAL_ERROR "prebuild.py: ${PREBUILD_RESULT}")
 endif()
 
-if(EMSCRIPTEN)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fexceptions -O3")
-elseif(MSVC)
+if(MSVC)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /EHsc /utf-8 /O2")
 else()
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fexceptions -O2")