diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2803f5c4be..bdb785de67 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -98,7 +98,7 @@ endif()
 # data into sections so they can be properly gc'd. -s: strip symbol.
 # -fno-exceptions -fno-rtti: disables exceptions and runtime type.
 set(CMAKE_CXX_FLAGS_RELEASE
-    "-O2 -ffunction-sections -fdata-sections -fno-exceptions -fno-rtti")
+    "-ffunction-sections -fdata-sections -fno-exceptions -fno-rtti")
 if(NOT APPLE)
   set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -s")
 endif()