set_optimization_flags: look specifically for optimization flags

Author: alandefreitas

cmake/functions/project_flags.cmake

@@ -50,27 +50,35 @@ endmacro()
 # @brief Set the default optimization flags in case the user didn't
 #        explicitly choose it with -DCMAKE_CXX_FLAGS
 macro(set_optimization_flags)
-    if (NOT CMAKE_CXX_FLAGS)
+    set(OPT_FLAGS /O1 /O2 /Ob /Od /Og /Oi /Os /Ot /Ox /Oy /favor -O0 -O1 -O -O2 -O3 -Os -Ofast -Og)
+    set(OPTIMIZATION_FLAG_IS_SET OFF)
+    string(REPLACE " " ";" CMAKE_CXX_FLAGS_LIST ${CMAKE_CXX_FLAGS})
+    foreach(FLAG ${CMAKE_CXX_FLAGS_LIST})
+        if (${FLAG} IN_LIST OPT_FLAGS)
+            message("CXX optimization flag is already set to ${FLAG}")
+            set(OPTIMIZATION_FLAG_IS_SET ON)
+        endif()
+    endforeach()
+
+    if (NOT OPTIMIZATION_FLAG_IS_SET)
         if (CMAKE_BUILD_TYPE STREQUAL "Debug")
             if (EMSCRIPTEN)
-                list(APPEND CMAKE_CXX_FLAGS "-O0 -g4")
+                list(APPEND CMAKE_CXX_FLAGS " -O0 -g4")
             elseif (MSVC)
-                list(APPEND CMAKE_CXX_FLAGS "/O0")
+                list(APPEND CMAKE_CXX_FLAGS " /O0")
             elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Clang" OR CMAKE_CXX_COMPILER_ID STREQUAL "AppleClang")
-                list(APPEND CMAKE_CXX_FLAGS "-O0")
+                list(APPEND CMAKE_CXX_FLAGS " -O0")
             else()
                 # https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html
-                list(APPEND CMAKE_CXX_FLAGS "-Og")
+                list(APPEND CMAKE_CXX_FLAGS " -Og")
             endif()
         else()
             if (MSVC)
-                list(APPEND CMAKE_CXX_FLAGS "/O2")
+                list(APPEND CMAKE_CXX_FLAGS " /O2")
             else()
-                list(APPEND CMAKE_CXX_FLAGS "-O2")
+                list(APPEND CMAKE_CXX_FLAGS " -O2")
             endif()
         endif()
         message("Setting CXX flags to default for ${CMAKE_BUILD_TYPE} mode (${CMAKE_CXX_FLAGS})")
-    else()
-        message("CXX flags are already set to ${CMAKE_CXX_FLAGS}")
     endif()
 endmacro()