On Wed, Nov 09, 2022 at 10:02:46AM +0100, Aldy Hernandez wrote:
> We can implement the op[12]_range entries for plus and minus in terms
> of each other. These are adapted from the integer versions.
I think for NANs the op[12]_range shouldn't act this way.
For the forward binary operations, we have the (maybe/known) NAN handling
of one or both NAN operands resulting in VARYING sign (maybe/known) NAN
result, that is the somehow the case for the reverse binary operations too,
if result is (maybe/known) NAN and the other op is not NAN, op is
VARYING sign (maybe/known) NAN, if other op is (maybe/known) NAN,
then op is VARYING sign maybe NAN (always maybe, never known).
But then for + we have the -INF + INF or vice versa into NAN, and that
is something that shouldn't be considered. If result isn't NAN, then
neither operand can be NAN, regardless of whether result can be
+/- INF and the other op -/+ INF.
Jakub
