https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88074
--- Comment #23 from joseph at codesourcery dot com <joseph at codesourcery dot com> --- And, yes, at least one extra bit in emin is needed for that sticky rounding code to work (because the user's source code may have a decimal constant that is slightly over half the least subnormal, and mpfr_strtofr needs to return a nonzero value for that code to work, meaning a value whose exponent is one smaller than the smallest exponent of any subnormal value that is actually representable in the floating-point format).
