CMake FindMPI CMAKE_PREFIX_PATH

April 1, 2022

We discovered a long-standing bug in CMake find_package(MPI) location hint via CMAKE_PREFIX_PATH variable or environment variable CMAKE_PREFIX_PATH. For an unknown number of releases, CMake FindMPI ignores CMAKE_PREFIX_PATH, which normally takes a high priority in the search order. To workaround this issue, use variable MPI_ROOT to tell FindMPI where to look for MPI.