checking only constexpr

Author: DiamonDinoia

CMakeLists.txt

@@ -20,31 +20,13 @@ if (CMAKE_CXX_COMPILER_ID IN_LIST GNU_LIKE_FRONTENDS)
             -freciprocal-math
             -fmerge-all-constants
             -ftree-vectorize
-            -fimplicit-constexpr
-    )
 
-    # Create a temporary list to hold the valid flags
-    set(FINUFFT_CXX_FLAGS_RELEASE_VALID)
-
-    # Check each flag
-    foreach(flag ${FINUFFT_CXX_FLAGS_RELEASE})
-        string(FIND "${flag}" "=" EQUAL_SIGN_POS)
-        if (EQUAL_SIGN_POS GREATER 0)
-            string(SUBSTRING "${flag}" 0 ${EQUAL_SIGN_POS} BASE_FLAG)
-        else()
-            set(BASE_FLAG ${flag})
-        endif()
-
-        check_cxx_compiler_flag("${BASE_FLAG}" flag_supported)
-        if(flag_supported)
-            list(APPEND FINUFFT_CXX_FLAGS_RELEASE_VALID "${flag}")
-        else()
-            message(STATUS "Flag ${flag} is not supported by the compiler and will be removed.")
-        endif()
-    endforeach()
-
-    # Replace the original list with the valid flags list
-    set(FINUFFT_CXX_FLAGS_RELEASE ${FINUFFT_CXX_FLAGS_RELEASE_VALID})
+    )
+    # if -fimplicit-constexpr is supported, add it to the list of flags
+    check_cxx_compiler_flag("-fimplicit-constexpr" COMPILER_SUPPORTS_FIMPLICIT_CONSTEXPR)
+    if (COMPILER_SUPPORTS_FIMPLICIT_CONSTEXPR)
+        list(APPEND FINUFFT_CXX_FLAGS_RELEASE -fimplicit-constexpr)
+    endif ()
     set(FINUFFT_CXX_FLAGS_RELWITHDEBINFO -g ${FINUFFT_CXX_FLAGS_RELEASE})
 endif ()