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RE: Popcount optimization using AVX512 - Mailing list pgsql-hackers

From Amonson, Paul D
Subject RE: Popcount optimization using AVX512
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Msg-id BL1PR11MB5304D41D49B56986097713AFDC3A2@BL1PR11MB5304.namprd11.prod.outlook.com
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In response to Re: Popcount optimization using AVX512  (Nathan Bossart <nathandbossart@gmail.com>)
Responses Re: Popcount optimization using AVX512
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> A counterexample is the CRC32C code.  AFAICT we assume the presence of
> CPUID in that code (and #error otherwise).  I imagine its probably safe to
> assume the compiler understands CPUID if it understands AVX512 intrinsics,
> but that is still mostly a guess.

If AVX-512 intrinsics are available, then yes you will have CPUID. CPUID is much older in the hardware/software
timelinethan AVX-512. 

Thanks,
Paul

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