[llvm] [InstCombine] Convert load from LUT into a select (PR #98339)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Compile-time impact: https://llvm-compile-time-tracker.com/compare.php?from=32cf91abb22bc0db5bb4f9c077d7564ded663e5a&to=2aeb3d25dd8543120f87e5869b4bea76fa7274b1&stat=instructions:u

https://github.com/llvm/llvm-project/pull/98339