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Re: [wg14/wg21 liaison] Rebasing C++ to C23

From: aaron_ng#inode.at aaron_ng#inode.at <aaron_ng_at_[hidden]>
Date: Fri, 3 May 2024 17:59:27 +0200 (CEST)
Ville Voutilainen via Liaison <liaison_at_[hidden]> hat am 02.05.2024 20:47 EEST geschrieben:
On Thu, 2 May 2024 at 20:44, Martin Uecker via Liaison
<liaison_at_[hidden]> wrote:
The two problems we discussed for C were
1. even when we require those stores (I see no problem there),
it is difficult to make sure that the information does not
leak in a different way, e.g. because registers or other
stack area are not cleared. WG14 was content with making the
intent clear.
We have Recommended Practice that we can use for the intent.
2. if there is UB afterwards then the extreme interpretation
of UB (which WG14 later rejected) makes the complete program have
no meaning.
That's a separable problem (because we have a separate proposal for an
optimization barrier),
but if it's a volatile write, it's an optimization barrier because the
volatile write is an observable effect.
So I don't think this is a problem.
At least in C volatile accesses are only ordered in respect to other volatile accesses.
Regards, Aaron Peter Bachmann

Received on 2024-05-03 15:59:29