Integrate LLVM at llvm/llvm-project@c6ad6901734f
Integrate LLVM at llvm/llvm-project@c6ad6901734f

Updates LLVM usage to match
[c6ad6901734f](https://github.com/llvm/llvm-project/commit/c6ad6901734f)

PiperOrigin-RevId: 452507624

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