Re: [RFC PATCH 1/2] audio/mixeng: Fix Clang 'int-conversion' warning

["Volker Rümelin" <vr_qemu@t-online.de>]

> Fix by using a 64-bit float for the conversion, before casting
> back to 32-bit float.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  audio/mixeng.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/audio/mixeng.c b/audio/mixeng.c
> index 739a500449..9946bfeaec 100644
> --- a/audio/mixeng.c
> +++ b/audio/mixeng.c
> @@ -271,7 +271,7 @@ f_sample *mixeng_clip[2][2][2][3] = {
>  #define CONV_NATURAL_FLOAT(x) (x)
>  #define CLIP_NATURAL_FLOAT(x) (x)
>  #else
> -static const float float_scale = UINT_MAX / 2.f;
> +static const float float_scale = UINT_MAX / 2.;

I would prefer an explicit cast of UINT_MAX to float. This is what we already have in audio/mixeng_template.h in the conf_* and clip_* functions with FLOAT_MIXENG defined. I think similar functions should look similar.

>  #define CONV_NATURAL_FLOAT(x) ((x) * float_scale)
>  
>  #ifdef RECIPROCAL

Please don't forget to fix the RECIPROCAL case.


Btw. the problem was reported here:
https://lists.nongnu.org/archive/html/qemu-devel/2020-03/msg02270.html

With best regards,
Volker