https://gcc.gnu.org/bugzilla/show_bug.cgi?id=113578
--- Comment #2 from Joseph S. Myers <jsm28 at gcc dot gnu.org> --- If a conversion from float to double (for passing in variable arguments) occurs at runtime on RISC-V, that will produce a positive-signed NaN (that's what the RISC-V floating-point instructions do). Cf. https://sourceware.org/bugzilla/show_bug.cgi?id=29501 (for strfrom functions).
