Convert this C macro kroundup32 to D mixin?

[Mike Parker via Digitalmars-d-learn]

On Saturday, 8 April 2017 at 10:02:01 UTC, Mike Parker wrote:

>
> I would expect if you implement it as a function the compiler 
> will inline it. You can always use the pragma(inline, true) [1] 
> with -inline to verify.
>
> [1] https://dlang.org/spec/pragma.html#inline

This gives me no error, so it does inline it.

T kroundup32(T)(T x) {
     pragma(inline, true);
     --(x);
     (x)|=(x)>>1;
     (x)|=(x)>>2;
     (x)|=(x)>>4;
     (x)|=(x)>>8;
     (x)|=(x)>>16;
     return ++(x);
}