Integrate LLVM at llvm/llvm-project@6f4d46076200
Integrate LLVM at llvm/llvm-project@6f4d46076200

Updates LLVM usage to match
[6f4d46076200](https://github.com/llvm/llvm-project/commit/6f4d46076200)

PiperOrigin-RevId: 351474229

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