diff --git a/CMakeLists.txt b/CMakeLists.txt
index 83c390b2c..36d750c19 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -69,12 +69,10 @@ cmake_dependent_option(ENABLE_ASSISTANT "Turn on assistant compiling." YES "ENAB
 
 set(CMAKE_CXX_STANDARD 11)
 
-if(NOT CMAKE_BUILD_TYPE)
-	set(CMAKE_BUILD_TYPE "Release")
-endif()
-
-set(CMAKE_CXX_FLAGS_RELEASE "-O2 -DNDEBUG")
-set(CMAKE_CXX_FLAGS_DEBUG "-g -DDEBUG")
+set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNDEBUG")
+set(CMAKE_CXX_FLAGS_MINSIZEREL "${CMAKE_CXX_FLAGS_MINSIZEREL} -DNDEBUG")
+set(CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELWITHDEBINFO} -DNDEBUG")
+set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DDEBUG")
 
 if(ENABLE_STATIC)
 	set(LINPHONE_LIBS_FOR_TOOLS linphone-static)