Some gcc flags aren't supported by clang as far as I know it's only optimization flags which aren't important to compile commands. There is an option to include extra flags but not to exclude flags.
He @ofir753 , thanks for your report. Not sure if I understand correctly, but in the latest version there is way to filter out specific compiler flags. (Read the man page of citnames command for the configuration file.)
Some gcc flags aren't supported by clang as far as I know it's only optimization flags which aren't important to compile commands. There is an option to include extra flags but not to exclude flags.