On: 1BRC merykitty's magic SWAR: 8 lines of code expla...

[gfody]

I imagine code like this gets auto-vectorized either right from the start or after Hotspot detects a hotspot

[haxen → gfody]

I wonder what you mean here. What code exactly would get auto-vectorized? Parsing the temperature surely not, since it's not in an array of fixed-size fields.

[gfody → haxen]

once you've done the work to implement parsing as branchless bitwise operations on integers I think that code can be extended automatically to operate on larger registers

[haxen → gfody]

I think it would work if that was the only code in the loop. But the loop spans several more nontrivial operations, including hashtable insertion.