linux-kernel - RE: [PATCH 01/10] compiler.h: add statically

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Message-ID: <b48e2f5dd8d64cbab471629ae03c7511@AcuMS.aculab.com>
Date: Fri, 6 Dec 2024 03:39:59 +0000
From: David Laight <David.Laight@...LAB.COM>
To: 'Vincent Mailhol' <mailhol.vincent@...adoo.fr>
CC: Linus Torvalds <torvalds@...ux-foundation.org>, Luc Van Oostenryck
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Subject: RE: [PATCH 01/10] compiler.h: add statically_false()

From: Vincent Mailhol
> Sent: 05 December 2024 15:26
> 
> On Thu. 5 Dec 2024 at 03:30, David Laight <David.Laight@...lab.com> wrote:
> > From: Vincent Mailhol
> > > Sent: 02 December 2024 17:33
> > >
> > > From: Vincent Mailhol <mailhol.vincent@...adoo.fr>
> > >
> > > For completion, add statically_false() which is the equivalent of
> > > statically_true() except that it will return true only if the input is
> > > known to be false at compile time.
> >
> > This is pretty much pointless.
> > It is just as easy to invert the condition at the call site.
> 
> To start with, I will argue that:
> 
>   statically_false(foo)
> 
> is more pretty than
> 
>   statically_true(!(foo))

Except that the test is more likely to be:
	statically_false(x > y)
and the invert is then
	statically_true(x <= y)

No different from C itself, there is no 'ifnot (condition) {...}'
(don't talk to me about perl...)

I suspect you need to pretty much remove all the comments that
cross-refer to statically_true() from the other patches.

So is_const_true() is just 'return true if the expression
is a 'non-zero constant integer expression'.

	David

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