linux-kernel - Re: [PATCH][next] comedi: remove redundant assignment to variable range

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Message-ID: <f61a1401-bc7f-4b8c-90d3-8327b9692422@mev.co.uk>
Date: Tue, 6 Feb 2024 12:19:41 +0000
From: Ian Abbott <abbotti@....co.uk>
To: Colin Ian King <colin.i.king@...il.com>,
 H Hartley Sweeten <hsweeten@...ionengravers.com>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc: kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH][next] comedi: remove redundant assignment to variable
 range

On 05/02/2024 18:04, Colin Ian King wrote:
> The variable range is being initialized with a value that is never
> read, it is being re-assigned later on. The initialization is
> redundant and can be removed.
> 
> Cleans up clang scan build warning:
> drivers/comedi/drivers/das08.c:180:2: warning: Value stored
> to 'range' is never read [deadcode.DeadStores]
> 
> Signed-off-by: Colin Ian King <colin.i.king@...il.com>
> ---
>   drivers/comedi/drivers/das08.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/drivers/comedi/drivers/das08.c b/drivers/comedi/drivers/das08.c
> index 5d5b9174f88a..49944ce1f813 100644
> --- a/drivers/comedi/drivers/das08.c
> +++ b/drivers/comedi/drivers/das08.c
> @@ -177,7 +177,6 @@ static int das08_ai_insn_read(struct comedi_device *dev,
>   	int ret;
>   
>   	chan = CR_CHAN(insn->chanspec);
> -	range = CR_RANGE(insn->chanspec);
>   
>   	/* clear crap */
>   	inb(dev->iobase + DAS08_AI_LSB_REG);

Thanks.  It looks like it gets reassigned to the same value further 
down, closer to the point where the value is used (within an `if` 
block), and so it doesn't matter which of the assignments is removed.

Reviewed-by: Ian Abbott <abbotti@....co.uk>

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