https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101223
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to rsand...@gcc.gnu.org from comment #8) > (In reply to Andrew Macleod from comment #7) > > wi::sub sets the overflow flag for 0 - 1 with 1 bit signed... so the > > comparison ends up being undefined, and we then make incorrect choices > > because we think we can. > Isn't that a bug in wi::sub though? I think we should fix it rather > than work around it in callers. How can one write 0 - 1 in 1-bit signed though? 1 isn't in the range... One can only do 0 + -1 which doesn't overflow, or 0 - -1 which does.
