LHC@Home had big issues[1] with AMD and Intel machines giving very different results to the same work unit. They traced it down to the exp() function behaving different, and ended up using a library[2] for anything more fancy than basic arithmetic.
[1] https://lhcathome.web.cern.ch/sites/default/files/OPENshort....
[2]: https://github.com/SixTrack/crlibm