[llvm] [GISel] Funnel shift combiner port from SelectionDAG ISel to GlobalISel (PR #135132)

[Min-Yih Hsu via llvm-commits]

mshockwave wrote:

> @mshockwave I have made a pre-commit test and a post-commit with the PR's title and description. Let me know if this is correct! And if so, then this can be merged :)

It's merged now. For future reference: you don't have to squash commits manually because Github would do that for you upon merging ("Squash and Merge" is the only option for LLVM at this moment). The pre-commit test system is also just for reviewing purposes (reviewers could navigate between different commits to see the difference), you don't really need to split it out for merging as they'll all gonna squashed into one at the end.

https://github.com/llvm/llvm-project/pull/135132