[Development] QTBUG-30440: restricting the SIMD files

[Oswald Buddenhagen]

On Thu, Aug 15, 2013 at 05:01:49PM +0000, Knoll Lars wrote:
> On 8/15/13 5:07 PM, "Sune Vuorela" <nospam at vuorela.dk> wrote:
> >On 2013-08-15, Thiago Macieira <thiago.macieira at intel.com> wrote:
> >> Uh... no, I don't think we can assume that. I'm afraid of Sune and
> >>other 
> >> distro packagers! :-)
> >
> >*whistles innocently*
> 
> But honestly: What's the oldest CPU you still consider supported? It must
> be a bit newer then i386, which I think our default build flags currently
> are still compatible with...
> 
as a matter of fact, linux recently stopped supporting i386. it's
seriously about time to ignore it. :D
intel atoms are based on P5 (are they still?), so that might be a
reasonable minimum.
otoh, it doesn't actually buy much over i386. P6 is the next really
interesting instruction set.
P6+sse2 (over a decade old) is *probably* a good default for desktop
builds. ^^

it would probably make most sense to have configure set some
target-specific optimization defaults (for the embedded devices it would
be possible to put them directly into the qmake specs).