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

[Nikita Popov via cfe-commits]

nikic wrote:

Okay, it looks like the mpeg2decode regression is indeed fixed. I think the only somewhat significant regression left is `Shootout-C++-ary2`, but in my IR diffs I don't see any regression there (only improvements with a bunch of conditions being optimized away).

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