From: Antonio Quartulli <a@unstable.cc>
To: David Miller <davem@davemloft.net>
Cc: netdev@vger.kernel.org, cake@lists.bufferbloat.net, toke@toke.dk,
jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
stephen@networkplumber.org
Subject: Re: [PATCH] net/sch_generic.h: use sizeof_member() and get rid of unused variable
Date: Wed, 20 May 2020 23:25:38 +0200 [thread overview]
Message-ID: <6759d98f-03fd-672c-e1eb-22ccc37e2b5d@unstable.cc> (raw)
In-Reply-To: <20200520.111717.835995575109387492.davem@davemloft.net>
On 20/05/2020 20:17, David Miller wrote:
> From: Antonio Quartulli <a@unstable.cc>
> Date: Wed, 20 May 2020 10:39:33 +0200
>
>> I don't think it's BUILD_BUG_ON()'s fault, because qcb->data is passed
>> to sizeof() first.
>>
>> My best guess is that gcc is somewhat optimizing the sizeof(gcb->data)
>> and thus leaving the gcb variable unused.
>
> If you remove the argument from the function but leave the BUILD_BUG_ON()
> calls the same, the compilation will fail.
>
> Any such optimization is therefore unreasonable.
>
> The variable is used otherwise compilation would not fail when you
> remove it right?
You're correct.
I guess this should be reported to gcc then.
Regards,
--
Antonio Quartulli
prev parent reply other threads:[~2020-05-20 21:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-19 9:13 [PATCH] net/sch_generic.h: use sizeof_member() and get rid of unused variable Antonio Quartulli
2020-05-19 22:40 ` David Miller
2020-05-20 8:39 ` Antonio Quartulli
2020-05-20 18:17 ` David Miller
2020-05-20 21:25 ` Antonio Quartulli [this message]
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