Re: [RFC] include/linux/make_type.h: Helpers for making u16/u32/u64 values

[Alexey Dobriyan]

On Wed, Feb 14, 2024 at 07:32:10PM +0200, Andy Shevchenko wrote:
> On Wed, Feb 14, 2024 at 08:20:55PM +0300, Alexey Dobriyan wrote:
> 
> ...
> 
> > Secondly,
> > 
> > 	#define make_u64(hi__, lo__)  ((u64)(hi__) << 32 | (u32)(lo__))
> > 
> > doesn't truncate hi, why?
> 
> Because it's not needed (the whole point AFAIU is to override promotion
> to a _signed_ type (int) and here it makes no difference)?

Well,

	make_u64((u64)-1, 0)

will return (u64)-1 unlike

	make_u16((u64)-1, 0)

which will return 0xff00.
BTW, I'm for truncation, but it should be done everywhere.

Thirdly, there were no users posted.