[llvm] LCA: migrate from DA to LAA; fix cost computation (PR #107691)

[Nikita Popov via llvm-commits]

nikic wrote:

> [Actual results](http://llvm-compile-time-tracker.com/compare.php?from=ec3e5c9e73d2d356ffa09a5f9075eba7e09040a8&to=28daa444b957bdf97707a489e3eb6b4c111ce264&stat=instructions:u).

A possible reason for this could be that we now have to compute *both* LAA and DA. Do you think it will be possible to change LoopInterchange to use LAA as well in the future, so only one will have to be computed?

https://github.com/llvm/llvm-project/pull/107691