This one required quite a bit of assembly surgery.
The only sched models that for cpu's that support avx2
but not avx512 are: haswell, broadwell, skylake, zen1-3
For load we have:
https://godbolt.org/z/Tce3osvcz - for intels Block RThroughput: =5.0; for ryzens, Block RThroughput: <=4.0
So pick cost of 5.
For store we have:
https://godbolt.org/z/oc3arEcnE - for intels Block RThroughput: =6.0; for ryzens, Block RThroughput: <=4.0
So pick cost of 6.
I'm directly using the shuffling asm the llc produced,
without any manual fixups that may be needed
to ensure sequential execution.