Changes to LLVM infrastructure
------------------------------
-* The legacy optimization pipeline has been removed.
+* The legacy optimization pipeline (``PassManagerBuilder.h``) has been removed.
+ See the `new pass manager docs <https://llvm.org/docs/NewPassManager.html>`_
+ for how to use the new pass manager APIs.
* Alloca merging in the inliner has been removed, since it only worked with the
legacy inliner pass. Backend stack coloring should handle cases alloca