[llvm] [SLSR] Adding a cost model considering register pressure (PR #213808)

[Justin Fargnoli via llvm-commits]

https://github.com/justinfargnoli commented:

I'm excited to see that other folks are interested in making more passes RP aware! However, this heuristic feels too naive/brittle to me. What alternative designs do you have in mind? 

https://github.com/llvm/llvm-project/pull/213808