https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100182
--- Comment #17 from Uroš Bizjak <ubizjak at gmail dot com> --- (In reply to Uroš Bizjak from comment #16) > (In reply to Jakub Jelinek from comment #15) > > Yes, but do they preserve all the bits and never modify any bit patterns, > > including qNaNs and sNaNs? I thought the point of using the fistp was that > > it preserves everything. > > Hm, they don't... This probably means we have to remove x87 peepholes, where an atomic store is followed by a DFmode read. x87 can't load and store DFmode untouched without fild/fistp pair.
