[clang] [llvm] [Clang][InstCombine] Recognise div/ldiv/lldiv libcalls (PR #215868)

[Matt Arsenault via cfe-commits]

https://github.com/arsenm commented:

This shouldn't mix the clang changes (which I also don't understand) and llvm pieces 

https://github.com/llvm/llvm-project/pull/215868