Re: staging: ks7010: Delete unnecessary uses of the variable "retval"

From: Julia Lawall
Date: Thu Jul 21 2016 - 08:54:37 EST




On Thu, 21 Jul 2016, SF Markus Elfring wrote:

> > I think the original code was fine.
>
> I suggest to reconsider involved implementation details once more.
>
>
> > x = blah(); if (x) ... is a perfectly familiar kernel coding pattern.
>
> I can agree to such a general information.
>
>
> > There is no benefit in terms of performance
>
> It might be possible that a good compiler can also optimise
> some unnecessary variable accesses away.

A compiler written by an undergrad can optimize the variable away in this
case. That's what compilers do.

> Examples for further background information:
> * "Minimize local variables"
> https://eventhelix.com/realtimemantra/basics/optimizingcandcppcode.htm#Minimize%20Local%20Variables
>
> * "Temporary Objects" by Danny Kalev
> http://www.informit.com/guides/content.aspx?g=cplusplus&seqNum=198
>
>
> > or understandability in dropping the variable.
>
> I guess that we have got different opinions on such an aspect.
>
> * Do you really want to assign every return value from a function call
> to an extra variable before it is used again?

If it's a choice between 1) function call on many lines, 2) function call
over 80 characters, and 3) extra variable, I definitely prefer the extra
variable.

julia

>
> * How many reading and understanding capacity do you need for each
> extra variable?
>
> Regards,
> Markus
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