[llvm] [InstCombine] Improve select simplification based on known bits (PR #97289)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Can we revert https://github.com/llvm/llvm-project/pull/66740 after landing this patch? @cyyself found that #66740 caused a significant compile-time regression in SLPVectorizer when building RTL simulator for https://github.com/OpenXiangShan/XiangShan. 


https://github.com/llvm/llvm-project/pull/97289