https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82554
--- Comment #1 from Ben Longbons <b.r.longbons at gmail dot com> --- Ugh, part of my explanation was wrong: it's not the difference of exponents, it's the number of common bits between the min and the (inclusive) max. That just happens to both be 1 bit when the (exclusive) max is twice the min.
