From: Paolo Bonzini <pbonzini@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>,
Markus Armbruster <armbru@redhat.com>
Cc: Laszlo Ersek <lersek@redhat.com>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH for 2.5] QEMU does not care about left shifts of signed negative values
Date: Tue, 17 Nov 2015 14:48:49 +0100 [thread overview]
Message-ID: <564B3041.3060702@redhat.com> (raw)
In-Reply-To: <CAFEAcA-m6WmZzCh_3Ruzu=jzaNKhzTJJQWwY_E6hGyYH=orYSA@mail.gmail.com>
On 17/11/2015 13:04, Peter Maydell wrote:
> > Using -fwrapv means that integer signed overflow is fully defined:
> > it wraps. When -fwrapv is used, there is no difference between
> > -fstrict-overflow and -fno-strict-overflow for integers.
>
> I thought this too, but note that it says "for integers". As Laszlo
> says, the reason to provide both is to get the -fno-strict-overflow
> behaviour for pointer arithmetic, which is not affected by -fwrapv.
And ubsan is not affected by -fno-strict-overflow...
Paolo
next prev parent reply other threads:[~2015-11-17 13:48 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-17 9:59 [Qemu-devel] [PATCH for 2.5] QEMU does not care about left shifts of signed negative values Paolo Bonzini
2015-11-17 10:19 ` Peter Maydell
2015-11-17 10:28 ` Paolo Bonzini
2015-11-17 10:36 ` Peter Maydell
2015-11-17 10:37 ` Paolo Bonzini
2015-11-17 10:42 ` Peter Maydell
2015-11-17 10:55 ` Peter Maydell
2015-11-17 10:57 ` Paolo Bonzini
2015-11-17 11:22 ` Peter Maydell
2015-11-17 12:10 ` Paolo Bonzini
2015-11-17 12:22 ` Peter Maydell
2015-11-17 10:41 ` Laszlo Ersek
2015-11-17 10:43 ` Paolo Bonzini
2015-11-17 10:52 ` Laszlo Ersek
2015-11-17 11:59 ` Markus Armbruster
2015-11-17 12:04 ` Peter Maydell
2015-11-17 12:17 ` Laszlo Ersek
2015-11-17 13:48 ` Paolo Bonzini [this message]
2015-11-17 12:18 ` Laszlo Ersek
2015-11-17 10:26 ` Markus Armbruster
2015-11-17 10:36 ` Laszlo Ersek
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