set(CUSTOM_FLAGS
  -mlow-precision-recip-sqrt
  -mlow-precision-sqrt
  -mlow-precision-div
)

string(JOIN " " CUSTOM_FLAGS_STR ${CUSTOM_FLAGS})
set(CMAKE_C_FLAGS_INIT   "${CMAKE_C_FLAGS} ${CUSTOM_FLAGS_STR}")
set(CMAKE_CXX_FLAGS_INIT "${CMAKE_CXX_FLAGS} ${CUSTOM_FLAGS_STR}")