[camel-cdr]

CNT and CNTP don't seem to be optional for SVE, from what I found. (unless you mean HISTCNT)

It seems to me like you want tp use CNTP on a bitset that tells you, which rows are relevant, skipping them if CNT is 0? Is that what you where describing?

[AlotOfReading]

I was confused and thinking that streaming mode and CNT were in separate extensions, but they're both in SME. My bad.

Anyway, essentially yes. My previous comment didn't mention all of the context. The join enforces that the result set is the intersection of the individual column sets, so it gets increasingly sparse as individual columns are computed. So I just maintain a bit tree that says which columns could populate the result set and skip computing the other lanes, which depends on the vector width and benefits from knowing it at compile time.