https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93806
--- Comment #10 from Rich Felker <bugdal at aerifal dot cx> --- I don't think it's at all clear that -fno-signed-zeros is supposed to mean the programmer is promising that their code has behavior independent of the sign of zeros, and that any construct which would be influenced by the sign of a zero has undefined behavior. I've always read it as a license to optimize in ways that disregard the sign of a zero or change the sign of a zero, but with internal consistency of the program preserved. If -fno-signed-zeros is really supposed to be an option that vastly expands the scope of what's undefined behavior, rather than just removing part of Annex F and allowing the unspecified quality of floating point results that C otherwise allows in the absence of Annex F, it really needs a much much bigger warning in its documentation!
