Integrate LLVM at llvm/llvm-project@2dfb66833fd2
Integrate LLVM at llvm/llvm-project@2dfb66833fd2

Updates LLVM usage to match
[2dfb66833fd2](https://github.com/llvm/llvm-project/commit/2dfb66833fd2)

PiperOrigin-RevId: 394116837

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