Integrate LLVM at llvm/llvm-project@156b1e6ba848
Integrate LLVM at llvm/llvm-project@156b1e6ba848

Updates LLVM usage to match
[156b1e6ba848](https://github.com/llvm/llvm-project/commit/156b1e6ba848)

PiperOrigin-RevId: 416545713

google-research/structured-additive-IR,google-research/structured-additive-IR