https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85957
Andrew Pinski <pinskia at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|UNCONFIRMED |RESOLVED Resolution|--- |DUPLICATE --- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> --- >(calculated from float types) Which is exactly just that. 64bit float point does not have 64bit of precision but rather 53bits. On x86, since it uses 80bit fpu internally and does not round between the intermediate steps which is why you are getting two different answers. *** This bug has been marked as a duplicate of bug 323 ***