- ``externally_initialized`` variables would be initialized or modified
elsewhere. Particularly, CUDA or HIP may have host code to initialize
or modify ``externally_initialized`` device variables, which may not
be explicitly referenced on the device side but may still be used
through the host side interfaces. Not preserving them triggers the
elimination of them in the GlobalDCE and breaks the user code.
Reviewed By: yaxunl
Differential Revision: https://reviews.llvm.org/D105135