Integrate LLVM at llvm/llvm-project@6883042528d0
Integrate LLVM at llvm/llvm-project@6883042528d0

Updates LLVM usage to match
[6883042528d0](https://github.com/llvm/llvm-project/commit/6883042528d0)

PiperOrigin-RevId: 346606080

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