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From: David Laight <David.Laight@ACULAB.COM>
To: 'Alexey Dobriyan' <adobriyan@gmail.com>,
	"akpm@linux-foundation.org" <akpm@linux-foundation.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] Drop -Wdeclaration-after-statement
Date: Fri, 25 Feb 2022 10:01:23 +0000	[thread overview]
Message-ID: <59387c6677af43c18d434b4f3c1e5430@AcuMS.aculab.com> (raw)
In-Reply-To: <YhiQPhsoODiXRAPy@localhost.localdomain>

From: Alexey Dobriyan
> Sent: 25 February 2022 08:16
> 
> Putting declarations before statement is relict of single pass compiler
> era. It was necessary to allocate stack slots before generating code.
> 
> Recently added static_assert() is a declaration. -Wdeclaration-after-statement
> prevents its placement anywhere in the code for no reason.

That could enclose its declaration inside a block.
But then it wouldn't be usable at global scope (is it anyway?)

> Placing variable declarations in the beginning of the block increases
> variable "LOC lifetime" so to speak and chances that it will be misused.
> This is very low probability bug but still. Declaring variables right
> before first use will make "LOC lifetime" smaller.

NAK it makes it very hard for a human (some of us are) to find
the declaration.

Indeed putting them anywhere other that the top of a function
or the top of a very short code block makes them hard to find.

	David

-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)

  reply	other threads:[~2022-02-25 10:01 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-25  8:15 Alexey Dobriyan
2022-02-25 10:01 ` David Laight [this message]
2022-02-25 17:24   ` Alexey Dobriyan
2022-02-26  1:10 ` Andrew Morton
  -- strict thread matches above, loose matches on Subject: below --
2019-03-10 13:35 Alexey Dobriyan
2019-03-12  0:38 ` Andrew Morton
2019-03-12 17:24   ` Alexey Dobriyan
2019-03-12 19:50     ` Andrew Morton
2019-03-12 20:18       ` Alexey Dobriyan
2019-03-12 20:53         ` Andrew Morton
2019-03-12 20:24       ` Alexey Dobriyan

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