[llvm] Reland "Redesign Straight-Line Strength Reduction (SLSR) (#162930)" (PR #169614)

[Artem Belevich via llvm-commits]

Artem-B wrote:

Considering that there appear to be nontrivial changes it's not exactly a re-land. It's more of a new iteration.

Would it be possible for you to re-stack you changes in a way that the original reverted patch is the starting point, so we can see what exactly has changed to fix the problem, so we do not have to go over complete patch of 2K lines of changes, again, and only deal with the incremental changes.

Including reviewers of the original patch would also be useful.

https://github.com/llvm/llvm-project/pull/169614