[llvm] [InstCombine] Simplify select using KnownBits of condition (PR #95923)

[Yingwei Zheng via llvm-commits]

dtcxzyw wrote:

Top 5 improvements:
  meshlab/MarchingCubes.cpp.ll 678109485 659907628 -2.68%
  c3c/tokens.c.ll 145223091 141469919 -2.58%
  tev/HelpWindow.cpp.ll 1039474883 1012684821 -2.58%
  faiss/HNSW.cpp.ll 3522270697 3438578766 -2.38%
  rust-analyzer-rs/4ifo5x52byu175vr.ll 302363407 296249464 -2.02%
Top 5 regressions:
  eastl/TestBitset.cpp.ll 7448097780 8128445212 +9.13%
  hwloc/bitmap.ll 1263490817 1334914518 +5.65%
  abc/rsbDec6.c.ll 1330779608 1379597304 +3.67%
  gromacs/lincs.cpp.ll 4224451840 4378129884 +3.64%
  z3/util.cpp.ll 141417444 146449050 +3.56%
Overall: 0.04440040%

https://github.com/llvm/llvm-project/pull/95923