linux-kernel - Re: [PATCH] ALSA: hda: generic: Remove redundant assignment to dac and dacs[i]

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Date:   Mon, 10 May 2021 12:57:28 +0200
From:   Amadeusz Sławiński 
        <amadeuszx.slawinski@...ux.intel.com>
To:     Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>, perex@...ex.cz
Cc:     alsa-devel@...a-project.org, tiwai@...e.com,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ALSA: hda: generic: Remove redundant assignment to dac
 and dacs[i]

On 5/10/2021 12:41 PM, Jiapeng Chong wrote:
> Variable dac and dacs[i] is set to zero, but this value is never read as
> it is overwritten or not used later on, hence it is a redundant assignment
> and can be removed.
> 
> Clean up the following clang-analyzer warning:
> 
> sound/pci/hda/hda_generic.c:1436:4: warning: Value stored to 'dac' is
> never read [clang-analyzer-deadcode.DeadStores].
> 
> Reported-by: Abaci Robot <abaci@...ux.alibaba.com>
> Signed-off-by: Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>
> ---
>   sound/pci/hda/hda_generic.c | 1 -
>   1 file changed, 1 deletion(-)
> 
> diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
> index b638fc2..cce1bf7 100644
> --- a/sound/pci/hda/hda_generic.c
> +++ b/sound/pci/hda/hda_generic.c
> @@ -1433,7 +1433,6 @@ static int try_assign_dacs(struct hda_codec *codec, int num_outs,
>   			path = snd_hda_add_new_path(codec, dac, pin, 0);
>   		}
>   		if (!path) {
> -			dac = dacs[i] = 0;
>   			badness += bad->no_dac;
>   		} else {
>   			/* print_nid_path(codec, "output", path); */
> 

Not entirely true... dacs is passed by pointer, so value assigned to it 
can be used somewhere else.