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Re: sse{2,3,4.2}, altivec, neon, ...

On Wed, Aug 09, 2017 at 11:56:32PM +0200, Adam Borowski wrote:
> Thus, it'd be nice to have a way to automatically detect such cases, but I
> don't know of a anything better than testing manually.  Which is extra unfun
> as any pre-sse2 (or pre-sse3) machine is crummy to the extreme, making
> unaccelerated qemu significantly faster than real silicon.  And neither is
> fast enough to not make such testing a pain in the posterior.

You cannot reliably do this, e.g. the bad instructions might be used 
only in some part of the program/library that the testing doesn't hit.

One nice part about including it in lintian is that this gives the 
maintainer a standard way to indicate that the package had been
confirmed to only select such instructions after autodetection of
the cpu features by adding a lintian override.



       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

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