diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index acf46afe7..445967a88 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -39,14 +39,7 @@ endif()
 
 execute_process(COMMAND git rev-parse --short HEAD OUTPUT_VARIABLE GIT_VERSION ERROR_QUIET)
 
-set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -g -O0 -Wall -DSLIC3R_DEBUG")
-set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -O3 -Wall")
 
-if(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.7.0)
-    if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7.3)
-       set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-inline-small-functions")
-    endif(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7.3)
-endif(CMAKE_CXX_COMPILER_VERSION VERSION_GREATER 4.7.0)
 
 set(CMAKE_INCLUDE_CURRENT_DIR ON)