Re: refactor architecture-specific popcount code

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От Nathan Bossart
Тема Re: refactor architecture-specific popcount code
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Msg-id aZjTLiA9xFjQpJ7G@nathan
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Ответ на Re: refactor architecture-specific popcount code  (Nathan Bossart <nathandbossart@gmail.com>)
Ответы Re: refactor architecture-specific popcount code
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On Fri, Feb 20, 2026 at 09:39:38AM -0600, Nathan Bossart wrote:
> I spent some time looking at how clang/gcc compiled the plain-C version on
> various architectures [0], and I was pleasantly surprised to discover that
> at some point in recent history they started automatically converting it to
> special popcount instructions.  I suspect that you'd see better results on
> ppc64le if you upgraded the compiler...

If we're willing to rely on this behavior, we could even remove
pg_popcount64_neon() and pg_popcount64_sse42().  We still need to add
"pg_attribute_target("popcnt")" and a corresponding configure check for the
x86 stuff, so it's not as impressive from a code-removal standpoint, but it
at least allows us to remove some uses of intrinsics and inline assembly.

-- 
nathan

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