[llvm] [NVPTX] Improve copy avoidance during lowering. (PR #106423)

[Artem Belevich via llvm-commits]

Artem-B wrote:

> I'll test the changes on a large set of compilations. If nothing interesting pops up, I can trim down collection of data that's not strictly necessary. Or put it under LLVM_DEBUG.

The patch appears to work fine on our tests. So, unless there are no further comments/objections, I'll land it tomorrow.

https://github.com/llvm/llvm-project/pull/106423