https://gcc.gnu.org/bugzilla/show_bug.cgi?id=121652
--- Comment #10 from Joseph S. Myers <jsm28 at gcc dot gnu.org> --- FE_SNANS_ALWAYS_SIGNAL is, as quoted, about operations *with floating-point results*. The classification macros are bound to IEEE operations that must not raise "invalid" for any inputs. isnan wrongly raising exceptions is bug 66462. (Comparison macros, however, unlike classification ones, should raise "invalid" for signaling NaNs.)
