Integrate LLVM at llvm/llvm-project@178c2b4c1eb1
Integrate LLVM at llvm/llvm-project@178c2b4c1eb1

Updates LLVM usage to match
[178c2b4c1eb1](https://github.com/llvm/llvm-project/commit/178c2b4c1eb1)

PiperOrigin-RevId: 386323643

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