[clang] [llvm] [OpenMP] Preserve the original address when `use_device_ptr/addr` lookup fails. (PR #174659)

[Abhinav Gaba via cfe-commits]

abhinavgaba wrote:

@jhuber6, @shiltian, if you don't have the bandwidth to review this and https://github.com/llvm/llvm-project/pull/169603, @adurang can probably help review. The changes are fairly small/straight-forward.

https://github.com/llvm/llvm-project/pull/174659