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From: Olaf Hering <olaf@aepfle.de>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: xen-devel@lists.xensource.com, qemu-devel@nongnu.org
Subject: [Qemu-devel] qemu-upstream compile failure in intel_iommu.c:vtd_context_device_invalidate
Date: Wed, 27 Jan 2016 19:23:52 +0100	[thread overview]
Message-ID: <20160127182352.GA5526@aepfle.de> (raw)

Compiling qemu-xen at 2ce1d30 ("xenfb.c: avoid expensive loops when prod
<= out_cons") leads to this error with -O1:

xen.git/tools/qemu-xen-dir/hw/i386/intel_iommu.c: In function ‘vtd_context_device_invalidate’:
xen.git/tools/qemu-xen-dir/hw/i386/intel_iommu.c:911:46: error: ‘mask’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
             if (vtd_as && ((devfn_it & mask) == (devfn & mask))) {
                                              ^
It works with -O2. From the code flow its clear that mask is always
initialized. Looks like gcc 5.2.1 does no proper diagnostic at -O1.
What should be done with such issues, are they fixed in the code?

Olaf

WARNING: multiple messages have this Message-ID (diff)
From: Olaf Hering <olaf@aepfle.de>
To: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: xen-devel@lists.xensource.com, qemu-devel@nongnu.org
Subject: qemu-upstream compile failure in intel_iommu.c:vtd_context_device_invalidate
Date: Wed, 27 Jan 2016 19:23:52 +0100	[thread overview]
Message-ID: <20160127182352.GA5526@aepfle.de> (raw)

Compiling qemu-xen at 2ce1d30 ("xenfb.c: avoid expensive loops when prod
<= out_cons") leads to this error with -O1:

xen.git/tools/qemu-xen-dir/hw/i386/intel_iommu.c: In function ‘vtd_context_device_invalidate’:
xen.git/tools/qemu-xen-dir/hw/i386/intel_iommu.c:911:46: error: ‘mask’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
             if (vtd_as && ((devfn_it & mask) == (devfn & mask))) {
                                              ^
It works with -O2. From the code flow its clear that mask is always
initialized. Looks like gcc 5.2.1 does no proper diagnostic at -O1.
What should be done with such issues, are they fixed in the code?

Olaf

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             reply	other threads:[~2016-01-27 18:37 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-27 18:23 Olaf Hering [this message]
2016-01-27 18:23 ` qemu-upstream compile failure in intel_iommu.c:vtd_context_device_invalidate Olaf Hering
2016-01-28  8:45 ` [Qemu-devel] " Paolo Bonzini
2016-01-28  8:45   ` Paolo Bonzini
2016-01-28 10:07   ` [Qemu-devel] " Peter Maydell
2016-01-28 10:07     ` Peter Maydell

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