https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67570
--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- If I understand what you are doing correctly, this is an unnormal representation (exponent not zero or maximal, explicit MSB of mantissa zero). Such representations, which cannot be produced by floating-point operations, are considered trap representations in C terms (undefined behavior if used, no consistency expected or required). Valid representations must have that MSB set for nonzero exponents and clear for zero exponents.
