https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92046
--- Comment #2 from Richard Biener <rguenth at gcc dot gnu.org> --- Created attachment 47014 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=47014&action=edit prototype Something like this. Note the behavior changes if the user manually specifies any of the parameters. We'd need to add a maybe_get_and_adjust_param_value that gets the unaltered value if the user specified it. But for that we'd have to hard pass-in global_options and global_options_set (or hardcode it in params.c). But then the behavior between -O2 and -O2 --param max-stores-to-sink=2 would be different (even though that's the documented default of the --param) - which is btw the current behavior. We could check against the default value but that means the behavior is different if targets change the param and the behavior differs between --param X=default and X=default-1 (drastically in the case of dropping to zero). I think for the vectorizer the only problematic case is PARAM_VECT_MAX_VERSION_FOR_ALIAS_CHECKS, the others are documented to be turned off. Likewise max-stores-to-sink. So I made vect-maxversion-for-alias-checks adjusted relatively with -fvect-cost-model=cheap so a global changed --param still has an effect.
