Re: Improve CRC32C performance on SSE4.2

Nathan Bossart <nathandbossart@gmail.com> writes:
> On Mon, Jun 23, 2025 at 10:51:21AM -0400, Tom Lane wrote:
>> This has broken the build completely on my RHEL8 x86_64 box,
>> with gcc 8.5.0:

> Unfortunately, this will probably require more than replacing
> _mm512_castsi512_si128 with _mm512_zextsi512_si128 because the latter
> doesn't exist.

I was imagining just including _mm512_zextsi128_si512() in the
code being tested during configure, so that we fall back to
the non-AVX-512 code if the compiler is too old to have it.
I don't really feel a need to work harder than that.

            regards, tom lane