[llvm] [llvm] Add NCD search on Array of basic blocks (PR #119355)

[Philip Reames via llvm-commits]

https://github.com/preames requested changes to this pull request.

Can you find a spot in existing code to use this factored out routine?  A few ideas:
FindIDom in ShrinkWrap
DeleteUnreachable in GenericDomConstruction.
SILowerI1Copies.cpp
HexagonFrameLowering.cpp

Basically, there's a whole bunch of these.  Please common a few so that we're not adding untested code. 

This appears to be identical code to findNearestCommonDominator.  Can we sink this into the GenericIDom layer instead?



https://github.com/llvm/llvm-project/pull/119355