Summary:
Nvidia PTX does not allow `.` to appear in identifiers, so OpenMP variant mangling now uses `$` to separate segments of the mangled name for variants of functions declared via `declare variant`.
Reviewers: jdoerfert, Hahnfeld
Reviewed By: jdoerfert
Subscribers: yaxunl, guansong, sstefan1, cfe-commits
Tags: #openmp, #clang
Differential Revision: https://reviews.llvm.org/D80439
Lukas Sommer