Re: Using POPCNT and other advanced bit manipulation instructions

On 14/02/2019 11:17, Alvaro Herrera wrote:
> On 2019-Feb-13, Alvaro Herrera wrote:
>
>> It definitely is ... plans have changed from using IndexOnly scans to
>> Seqscans, which is likely fallout from the visibilitymap_count() change.
> I think the problem here is that "unsigned long" is 32 bits in this
> machine:

[...]

 From my memory of reading of K&R many moons ago, it said that C only 
guarantees that the lengths are such that

byte <= half word <= word <= long

But I don't recall ever seeing a long less than 32 bits!


Cheers,
Gavin