diff --git a/CMakeLists.txt b/CMakeLists.txt
index 05c1bf0b..8299964a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -37,11 +37,7 @@ if (USE_COV)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fprofile-arcs -ftest-coverage -fprofile-update=atomic")
 endif ()
 
-IF (WIN32)
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0")
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0")
-    # native IO 用 libevent（select），不再用 Boost.Asio。
-ELSEIF (APPLE)
+IF (APPLE)
     if (USE_COV)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0 -Wno-non-pod-varargs")
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0")
@@ -50,6 +46,7 @@ ELSEIF (APPLE)
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
     endif ()
 ELSE ()
+    # Windows (MinGW) and Linux share the same policy: -O0 only for coverage builds.
     if (USE_COV)
         set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O0")
         set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O0")