[clang] [llvm] [ValueTracking] Add dominating condition support in computeKnownBits() (PR #73662)

[Nikita Popov via cfe-commits]

nikic wrote:

@bjope It looks like the InstCombine changes enable IndVars to perform LFTR, which is unprofitable in this case. Though the `umax(1)` call is actually completely unnecessary here, but SCEV doesn't realize it. I've put up https://github.com/llvm/llvm-project/pull/75039 to fix that. Does that improve things for you?

https://github.com/llvm/llvm-project/pull/73662