Re: [PATCH 10/11] softfloat: Sink frac_cmp in parts_pick_nan until needed

[Peter Maydell]

On Tue, 3 Dec 2024 at 20:40, Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> Move the fractional comparison to the end of the
> float_2nan_prop_x87 case.  This is not required for
> any other 2nan propagation rule.  Reorganize the
> x87 case itself to break out of the switch when the
> fractional comparison is not required.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>

> @@ -89,20 +84,24 @@ static FloatPartsN *partsN(pick_nan)(FloatPartsN *a, 
> FloatPartsN *b,
>           * return the NaN with the positive sign bit (if any).
>           */
>          if (is_snan(a->cls)) {
> -            if (is_snan(b->cls)) {
> -                which = cmp > 0 ? 0 : 1;
> -            } else {
> +            if (!is_snan(b->cls)) {
>                  which = is_qnan(b->cls) ? 1 : 0;
> +                break;
>              }
>          } else if (is_qnan(a->cls)) {
>              if (is_snan(b->cls) || !is_qnan(b->cls)) {

Pre-existing code, but isn't
   is_snan(X) || !is_qnan(X)
the same as
   !is_qnan(X)
?

thanks
-- PMM