https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97965
--- Comment #2 from Jason Merrill <jason at gcc dot gnu.org> ---
See also PR88683 and PR88173.
I notice that the match.pd REAL_CST patterns starting around line 4045 only
look at the RHS of the comparison, so that nan > inf is handled very
differently from inf < nan. And tree_swap_operands_p doesn't swap them around
to make it work properly.
#define inf __builtin_huge_val()
#define nan __builtin_nan("")
constexpr bool b1 = inf > nan;
constexpr bool b2 = nan < inf;
