[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%

Top 5 improvements:
  postgres/unicode_norm_shlib.ll 363748825 350961218 -3.52%
  meshlab/MarchingCubes.cpp.ll 675246704 656351184 -2.80%
  tev/HelpWindow.cpp.ll 1029062714 1002529143 -2.58%
  faiss/AdditiveQuantizer.cpp.ll 1493267399 1458937166 -2.30%
  faiss/InvertedLists.cpp.ll 1529590909 1496064094 -2.19%
Top 5 regressions:
  eastl/TestBitset.cpp.ll 7404525337 7721492909 +4.28%
  hwloc/bitmap.ll 1254672490 1289997586 +2.82%
  libwebp/upsampling.c.ll 1495289974 1528316818 +2.21%
  faiss/IndexScalarQuantizer.cpp.ll 635573896 649291704 +2.16%
  meshlab/meshfilter.cpp.ll 77037371771 78638508357 +2.08%
Overall: 0.04310683%

It looks better now :)




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