https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81120
--- Comment #3 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- Of course, such a test is fairly meaningless without -fsignaling-nans. Then, where long double and double have the same format, "Whether C assignment (6.5.16) (and conversion as if by assignment) to the same format is an IEC 60559 convertFormat or copy operation is implementation-defined, even if <fenv.h> defines the macro FE_SNANS_ALWAYS_SIGNAL (F.2.1)." from TS 18661-1 applies. That is, a test should not be expecting a particular choice of the signaling NaN being quieted or not by a conversion to the same format, including when that's a conversion from long double to double (and GCC will generally not quiet the signaling NaN in such a conversion, unless on an excess-precision architecture where simple loads of the narrower type quiet it).
