Re: [PATCH] coccinelle: improve array.cocci

> The current version checks if source and destination are of the same type,
> and whether the sizeof operand is either said type or an element of source
> or destination.  The new one does not.  So I don't see claim 4 ("Increase
> the precision") fulfilled, quite the opposite rather.  It can produce e.g.
> a transformation like this:
>
>  void f(int *dst, char *src, size_t n)
>  {
> -	memcpy(dst, src, n * sizeof(short));
> +	COPY_ARRAY(dst, src, n);
>  }
>
> The COPY_ARRAY there effectively expands to:
>
> 	memcpy(dst, src, n * sizeof(*dst));
>
> ... which is quite different -- if short is 2 bytes wide and int 4 bytes
> then we copy twice as many bytes as before.
>
> I think an automatic transformation should only be generated if it is
> safe.  It's hard to spot a weird case in a generated patch amid ten
> well-behaving ones.