Hello,
> That is necessary because most people consume PostgreSQL through
> packages from distributions that have to work on an Athlon II or
> whatever, so we can't just use -msse4.2 for every translation unit.
> So it becomes our job to isolate small bits of code that use newer
> instructions, if it's really worth the effort to do that, and supply
> our own runtime checks and provide a fallback.
Ok. That was my understanding so as to improve the portability/performance
compromise. I do not think that pgbench is worth the effort on this
particular point.
> [...] None of that seems worth it for something like this.
Indeed.
So, am I right to deducing that you are satisfied with the current status
of the patch, with the nbits implementation either based on popcount (v4)
or clz (v5) compiler intrinsics? I think that the clz option is better.
--
Fabien.