diff --git a/clang/include/clang/Driver/Options.td b/clang/include/clang/Driver/Options.td --- a/clang/include/clang/Driver/Options.td +++ b/clang/include/clang/Driver/Options.td @@ -243,7 +243,10 @@ // A boolean option which is opt-in in CC1. The positive option exists in CC1 and // Args.hasArg(OPT_ffoo) is used to check that the flag is enabled. -// This is useful if the option is usually disabled. +// +// This is useful if the option has positive semantics (e.g. `FastMath`) that is by +// default disabled (FastMath == 0), can be reaffirmed by -fno-fast-math (FastMath == 0) +// and enabled by -ffast-math (FastMath == 1). multiclass OptInFFlag flags=[], code keypath="", list