https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105414
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- (In reply to HaoChen Gui from comment #8) > (In reply to Jakub Jelinek from comment #7) > > Sure, but you don't want to do that at least if flag_trapping_math. > > Otherwise, the predicate would be tree_expr_signaling_nan_p and real_nan > > function with "", 1 as the middle 2 arguments can create it. But note that > > nothing in match.pd does that right now, so I don't think we should do it in > > this case either. > > If either of arguments is sNaN, fmin/max should return a qNaN. So I really > want to create a pattern in match.pd to do this. It needs to create a qNaN A sNaN should primarily raise an exception or raise a signal when used. So better not to fold it. Given that we don't fold anything else with sNaN, starting from sNaN + whatever etc., just folding it for something so rare as fmin/fmax would be weird.
