https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90248
--- Comment #12 from rguenther at suse dot de <rguenther at suse dot de> --- On Tue, 14 May 2019, pinskia at gcc dot gnu.org wrote: > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90248 > > --- Comment #10 from Andrew Pinski <pinskia at gcc dot gnu.org> --- > So I am trying to understand, the semantics here. > HONOR_SIGNED_ZEROS says -0.0 won't exist or that the sign of -0.0 and 0.0 > don't > matter? and what are the semantics if -0.0 shows up? > > If we treat -0.0 as 0.0, then all of the optimizations here should be removed. > If we treat -0.0 as undefined behavior if it shows up, then only two of the > lines need to be removed. > > Which is correct semantics for HONOR_SIGNED_ZEROS? The sign of a zero _result_ is undetermined. It doesn't say anything about signs of zero input values. That's contrary to HONOR_NANS/INFS (and -ffinite-math-only).
