Re: [RFC PATCH] include/qemu/host-utils: Remove the *_overflow wrappers

[Thomas Huth]

On 23/06/2022 23.29, Richard Henderson wrote:
> On 6/23/22 12:30, Peter Maydell wrote:
> > > -static inline bool sadd32_overflow(int32_t x, int32_t y, int32_t *ret)
> > > -{
> > > -#if __has_builtin(__builtin_add_overflow) || __GNUC__ >= 5
> > > -    return __builtin_add_overflow(x, y, ret);
> > > -#else
> > > -    *ret = x + y;
> > > -    return ((*ret ^ x) & ~(x ^ y)) < 0;
> > > -#endif
> > > -}
> >
> > I think I'd prefer to keep the wrapper functions and just delete
> > the fallback ifdeffery, but I guess I don't feel really strongly
> > about it. Richard, do you have an opinion?
>
> Likewise I don't feel strongly, but lean toward keeping the names.  I will 
> point out that without these names, one has to track down the type of each 
> argument to figure out what is, or is not, overflowing.

Yes, I checked the calling sites, and some do use different types indeed, 
but as far as I understood the __builtin_add_overflow(), it should be ok in 
our cases. Anyway, it's maybe less error prone to keep the wrapper with the 
fixed parameter types, so I'll send a v2 that just removes the #ifs instead.

 Thomas