Re: use ARM intrinsics in pg_lfind32() where available

On Sat, Aug 27, 2022 at 05:18:34PM -0400, Tom Lane wrote:
> In short, I think the critical part of 0002 needs to look more like
> this:
>
> +#elif defined(__aarch64__) && defined(__ARM_NEON)
> +/*
> + * We use the Neon instructions if the compiler provides access to them
> + * (as indicated by __ARM_NEON) and we are on aarch64. While Neon support is
> + * technically optional for aarch64, it appears that all available 64-bit
> + * hardware does have it. Neon exists in some 32-bit hardware too, but
> + * we could not realistically use it there without a run-time check,
> + * which seems not worth the trouble for now.
> + */
> +#include <arm_neon.h>
> +#define USE_NEON
> ...

Thank you for the analysis! I'll do it this way in the next patch set.

--
Nathan Bossart
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