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

[Philippe Mathieu-Daudé]

On 5/4/20 7:49 AM, Volker Rümelin wrote:
> > Fix by using a 64-bit float for the conversion, before casting
> > back to 32-bit float.
> >
> > Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> > ---
> >   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

Ah I missed that, I now feel safer knowing developers who understand 
this code are already trying to fix it, thanks Volker!

> With best regards,
> Volker