[llvm] [DAGCombiner] Option --combiner-select-seq (PR #134813)

[Anmol P. Paralkar via llvm-commits]

anmolparalkar-nxp wrote:

@ppetrovic98 In combiner-select-seq.ll, the '-stop-after=amdgpu-isel' crashes llc:
LLVM ERROR: "amdgpu-isel" pass is not registered.
That would change to: -stop-after=aarch64-isel
Here is the re-spin: [combiner-select-seq.txt](https://github.com/user-attachments/files/19766869/combiner-select-seq.txt)
PS: It would not accept the .ll format (hence used .txt); kindly rename, thanks. This test now passes. Please feel free to incorporate the respun combiner-select-seq.ll into your patch, thanks.
I also verified that the llvm-lit run has no regressions. 
My llvm sources are at today's f1dd6b3cf8d957f28e06f475c8a652f201fc830b and configured aarch64-none-elf
Thank you for reviving this work, lgtm.

https://github.com/llvm/llvm-project/pull/134813