Re: refactor architecture-specific popcount code

On Fri, Jan 30, 2026 at 12:06 AM Nathan Bossart
<nathandbossart(at)gmail(dot)com> wrote:
> [v5]

0001 - I'm pretty sure this is comparable to HEAD if the optimized
function is pg_popcount_sse42(). Has the AVX512 version been tested
with 8-byte inputs? That seems to have a lot of pre- and
post-processing involved. The inline wrapper only bypasses for 7 or
less bytes.

0002
- I tried running this on x86-64 with alignment sanitizer and no
alarms went off during "make check", but adding
pg_attribute_no_sanitize_alignment() would prevent surprises in the
future.
- I imagine that the old SIZEOF_VOID_P check is superfluous now, since
the whole file is gated by HAVE_X86_64_POPCNTQ.
- Maybe we can remove the aligned 32-bit path in
pg_popcount_(masked_)portable(), since that's on-topic for this patch
and would simplify things further.

--
John Naylor
Amazon Web Services