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From: Paolo Bonzini <pbonzini@redhat.com>
To: Markus Armbruster <armbru@redhat.com>,
	Peter Maydell <peter.maydell@linaro.org>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Frank Blaschka <frank.blaschka@de.ibm.com>,
	Frank Blaschka <blaschka@linux.vnet.ibm.com>,
	QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [PATCH 2/3 V3] s390: implement pci instructions
Date: Wed, 21 Jan 2015 16:32:30 +0100	[thread overview]
Message-ID: <54BFC68E.20105@redhat.com> (raw)
In-Reply-To: <87mw5cfdyy.fsf@blackfin.pond.sub.org>



On 21/01/2015 14:41, Markus Armbruster wrote:
> I suspect we shift signed values all over the place, without regard for
> signed overflow.  Machines are fine with that, but some day some
> compiler wiseguy may find a way to save a femtosecond or two for some
> program that never does that, breaking programs that do it, and then
> we'll be in trouble.

As I said before, if there was a way to save those femtoseconds, they
would have already tried.

More likely, the compiler people know they would become the main
attractions at pitch and feather spectacles, so they're not going to
treat that as undefined behavior.

Paolo

  parent reply	other threads:[~2015-01-21 15:32 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-01-09  8:04 [Qemu-devel] [PATCH 0/3 V3] add PCI support for the s390 platform Frank Blaschka
2015-01-09  8:04 ` [Qemu-devel] [PATCH 1/3 V3] s390: Add PCI bus support Frank Blaschka
2015-01-09 11:54   ` Cornelia Huck
2015-01-09  8:04 ` [Qemu-devel] [PATCH 2/3 V3] s390: implement pci instructions Frank Blaschka
2015-01-20  9:45   ` Markus Armbruster
2015-01-20 10:03     ` Cornelia Huck
2015-01-20 12:33       ` Markus Armbruster
2015-01-20 12:56         ` Markus Armbruster
2015-01-20 14:20           ` Frank Blaschka
2015-01-20 20:24             ` Markus Armbruster
2015-01-21 11:54               ` Markus Armbruster
2015-01-21 13:12                 ` Peter Maydell
2015-01-21 13:41                   ` Markus Armbruster
2015-01-21 14:41                     ` Peter Maydell
2015-01-21 15:32                     ` Paolo Bonzini [this message]
2015-01-21  9:49         ` Cornelia Huck
2015-01-09  8:04 ` [Qemu-devel] [PATCH 3/3 V3] kvm: extend kvm_irqchip_add_msi_route to work on s390 Frank Blaschka
2015-01-09 11:59 ` [Qemu-devel] [PATCH 0/3 V3] add PCI support for the s390 platform Cornelia Huck

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