Re: wineport: Add fast builtin & asm versions of ffs() + ctz() where supported.

[Alexandre Julliard]

Adam Martinson  writes:
> @@ -236,7 +241,40 @@ extern int getopt_long_only (int ___argc, char *const *___argv,
>  #endif  /* HAVE_GETOPT_LONG */
>
> #ifndef HAVE_FFS
> -int ffs( int x );
> - #if defined(__i386__) || defined(__x86_64__)
> -
>    #define HAVE_FFS
> -
>    static inline int ffs( int x )
> -
>    {
> -
>        if (!x)
> -
>        {
> -
>            return 0;
> -
>        }
> -
>        else
> -
>        {
> -
>            int ret;
> -
>            __asm__("bsfl %1, %0; incl %0" : "=r" (ret) : "r" (x));
> -
>            return ret;
> -
>        }
> -
>    }
> - #elif defined(__GNUC__) && GCC_VERSION >= 29503
> -
>    #define HAVE_FFS
> -
>    #define ffs(x) __builtin_ffs(x)
> - #else
> -
>    int ffs( int x );
> - #endif
>
> +#endif

You'd have to show benchmarks to prove that this complexity is
necessary. Given that ffs() should already be inlined on all decent
platforms, I doubt you'd be able to demonstrate a difference (if
anything, your version would be slower because of the extra increment).