Re: [PATCH 5/8] softfloat: Inline pick_nan_muladd into its caller

[David Hildenbrand <david@redhat.com>]

On 24.09.20 03:24, Richard Henderson wrote:
> Because of FloatParts, there will only ever be one caller.
> Inlining allows us to re-use abc_mask for the snan test.
> 
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
>  fpu/softfloat.c | 75 +++++++++++++++++++++++--------------------------
>  1 file changed, 35 insertions(+), 40 deletions(-)
> 
> diff --git a/fpu/softfloat.c b/fpu/softfloat.c
> index 3e625c47cd..e038434a07 100644
> --- a/fpu/softfloat.c
> +++ b/fpu/softfloat.c
> @@ -929,45 +929,6 @@ static FloatParts pick_nan(FloatParts a, FloatParts b, float_status *s)
>      return a;
>  }
>  
> -static FloatParts pick_nan_muladd(FloatParts a, FloatParts b, FloatParts c,
> -                                  bool inf_zero, float_status *s)
> -{
> -    int which;
> -
> -    if (is_snan(a.cls) || is_snan(b.cls) || is_snan(c.cls)) {
> -        s->float_exception_flags |= float_flag_invalid;
> -    }
> -
> -    which = pickNaNMulAdd(a.cls, b.cls, c.cls, inf_zero, s);
> -
> -    if (s->default_nan_mode) {
> -        /* Note that this check is after pickNaNMulAdd so that function
> -         * has an opportunity to set the Invalid flag.
> -         */
> -        which = 3;
> -    }
> -
> -    switch (which) {
> -    case 0:
> -        break;
> -    case 1:
> -        a = b;
> -        break;
> -    case 2:
> -        a = c;
> -        break;
> -    case 3:
> -        return parts_default_nan(s);
> -    default:
> -        g_assert_not_reached();
> -    }
> -
> -    if (is_snan(a.cls)) {
> -        return parts_silence_nan(a, s);
> -    }
> -    return a;
> -}
> -
>  /*
>   * Returns the result of adding or subtracting the values of the
>   * floating-point values `a' and `b'. The operation is performed
> @@ -1366,7 +1327,41 @@ static FloatParts muladd_floats(FloatParts a, FloatParts b, FloatParts c,
>       * off to the target-specific pick-a-NaN routine.
>       */
>      if (unlikely(abc_mask & float_cmask_anynan)) {
> -        return pick_nan_muladd(a, b, c, inf_zero, s);
> +        int which;
> +
> +        if (unlikely(abc_mask & float_cmask_snan)) {
> +            float_raise(float_flag_invalid, s);
> +        }
> +
> +        which = pickNaNMulAdd(a.cls, b.cls, c.cls, inf_zero, s);
> +
> +        if (s->default_nan_mode) {
> +            /*
> +             * Note that this check is after pickNaNMulAdd so that function
> +             * has an opportunity to set the Invalid flag for inf_zero.
> +             */
> +            which = 3;
> +        }
> +
> +        switch (which) {
> +        case 0:
> +            break;
> +        case 1:
> +            a = b;
> +            break;
> +        case 2:
> +            a = c;
> +            break;
> +        case 3:
> +            return parts_default_nan(s);
> +        default:
> +            g_assert_not_reached();
> +        }
> +
> +        if (is_snan(a.cls)) {
> +            return parts_silence_nan(a, s);
> +        }
> +        return a;
>      }
>  
>      if (unlikely(inf_zero)) {
> 

Not sure if that increases readability of muladd_floats() ... sometimes
there is good reason to factor out stuff into subfunctions to improve
readability.

But the change itself looks good to me

Reviewed-by: David Hildenbrand <david@redhat.com>

-- 
Thanks,

David / dhildenb