Mpi bcast (rust-lang#224)

* Merging of old MPI changes into the modern main branch.

* Merging in old MPI work.

Co-authored-by: William Moses <[email protected]>

* Combating the errors.

* Correct call to getOrInsertGlobal, returning a global pointer.

* Add much finer scaffold for the broadcast operation.

* Add functionality to complete the MPI_Bcast primitive.

* First draft of test for MPI_Bcast.

* Fix test case

* Fix emission

* lazy init

* Correct MPI bcast

* Correct clang formatting and correct mpi bcast test.

* Correct clang formatting errors.

* Fix LLVM 7 error.

* Fix mpi_bcast to work with LLVM 7/8.

Co-authored-by: Ludger Paehler <[email protected]>

Author: wsmoses

enzyme/Enzyme/ActivityAnalysis.cpp

@@ -89,6 +89,7 @@ std::set<std::string> KnownInactiveFunctions = {
     "printf",
     "vprintf",
     "puts",
+    "fflush",
     "__enzyme_float",
     "__enzyme_double",
     "__enzyme_integer",