[llvm] [InstCombine] SimplifyDemandedBits: add basic bitcast handling, Fixes #173780 (PR #173865)

[Ayush Pareek via llvm-commits]

ayushpareek2003 wrote:

Now the function can peek through bitcasts of the same size and know which bits are 0 or 1, which helps simplify code correctly

https://github.com/llvm/llvm-project/pull/173865