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From: Peter Maydell <peter.maydell@linaro.org>
Date: Tue, 8 Dec 2015 12:54:09 +0000
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Subject: Re: [Qemu-devel] [v3 3/3] configure: add options to config avx2
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To: Liang Li <liang.z.li@intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>, Juan Quintela <quintela@redhat.com>, QEMU Developers <qemu-devel@nongnu.org>, "Dr. David Alan Gilbert" <dgilbert@redhat.com>, Stefan Hajnoczi <stefanha@redhat.com>, Amit Shah <amit.shah@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>, Richard Henderson <rth@twiddle.net>

On 8 December 2015 at 12:08, Liang Li <liang.z.li@intel.com> wrote:
> Add the '--enable-avx2' & '--disable-avx2' option so as to config
> the AVX2 instruction optimization.
>
> If '--disable-avx2' is not set, configure will detect if the compiler
> can support AVX2 option, if yes, AVX2 optimization is eabled, else
> disabled.

Is the configure option necessary? For other things like
this (eg our use of SSE2 or Altivec) we just go ahead and
use the feature if the compiler supports it.

When would somebody building QEMU want to disable this option?

thanks
-- PMM