Integrate LLVM at llvm/llvm-project@861dbe1a021e
Integrate LLVM at llvm/llvm-project@861dbe1a021e

Updates LLVM usage to match
[861dbe1a021e](https://github.com/llvm/llvm-project/commit/861dbe1a021e)

PiperOrigin-RevId: 359091800

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