From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Laszlo Ersek <lersek@redhat.com>,
Markus Armbruster <armbru@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH v2 for 2.5] QEMU does not care about left shifts of signed negative values
Date: Tue, 17 Nov 2015 19:21:34 +0100 [thread overview]
Message-ID: <564B702E.4070806@redhat.com> (raw)
In-Reply-To: <CAFEAcA8S-DOnar-_-rVd4SehZ8bv0dqQ3MN_qgQGnyegezzghg@mail.gmail.com>
On 17/11/2015 19:19, Peter Maydell wrote:
> That doesn't seem like more than half-good news to me. In particular,
> if ubsan is still diagnosing these cases and they're still a
> problem in some constant expressions
Constant expressions are standardese for e.g.
static int x = 1 << 31;
It doesn't mean _all_ constants, and the warning only triggers with
-pedantic.
Regarding ubsan, give them some time to answer. :)
Paolo
> If the GCC folks don't want to go any further than that then
> I think we should prefer to avoid this UB. (And there's still
> the question of clang's position on this.)
next prev parent reply other threads:[~2015-11-17 18:21 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-17 14:09 [Qemu-devel] [PATCH v2 for 2.5] QEMU does not care about left shifts of signed negative values Paolo Bonzini
2015-11-17 14:47 ` Laszlo Ersek
2015-11-17 15:47 ` Markus Armbruster
2015-11-17 16:54 ` Laszlo Ersek
2015-11-17 17:06 ` Paolo Bonzini
2015-11-17 18:22 ` Markus Armbruster
2015-11-17 17:39 ` Markus Armbruster
2015-11-17 17:45 ` Paolo Bonzini
2015-11-17 18:19 ` Peter Maydell
2015-11-17 18:21 ` Paolo Bonzini [this message]
2015-11-17 18:24 ` Peter Maydell
2015-11-17 18:36 ` Paolo Bonzini
2015-11-17 18:40 ` Peter Maydell
2015-11-17 18:41 ` Markus Armbruster
2015-11-17 19:54 ` Paolo Bonzini
2015-11-17 18:24 ` Markus Armbruster
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