[llvm] [InstCombineCompare] Use known bits to insert assume intrinsics. (PR #96017)

[Mikhail Gudim via llvm-commits]

mgudim wrote:

@nikic @goldsteinn @dtcxzyw 

I have put this under a flag and disabled it by default. Can we merge this now? As @goldsteinn suggested, I will look into discounting assume uses.

https://github.com/llvm/llvm-project/pull/96017