Re: [PATCH v2 8/9] bfs: remove multiple assignments

[Adrian Bunk <trivial@kernel.org>]

On Sat, Jan 26, 2008 at 06:35:41PM +0000, Tigran Aivazian wrote:
> On Sat, 26 Jan 2008, Dmitri Vorobiev wrote:
>> -	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME_SEC;
>> +	inode->i_mtime = CURRENT_TIME_SEC;
>> +	inode->i_atime = CURRENT_TIME_SEC;
>> +	inode->i_ctime = CURRENT_TIME_SEC;
>
> multiple assignments like "x = y = z = value;" can potentially (depending 
> on the compiler and arch) be faster than "x = value; y = value; z=value;"

Only depending on the compiler, and recent gcc versions are quite good 
at optimizing code.

> I am surprized that this script complains about them as it is a perfectly 
> valid thing to do in C.

Checkpatch warns about the something already documented in 
Documentation/CodingStyle:

<--  snip  -->

Don't put multiple assignments on a single line either.  Kernel coding style
is super simple.  Avoid tricky expressions.

<--  snip  -->

Nobody claims it wasn't perfectly valid C code, the point is that 
multiple assignments on a single line are harder to read.

> But this is not a "big deal", so I don't mind.
>
> Kind regards
> Tigran

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
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       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed