[clang] [Inliner] Improve propagation of return attributes. (PR #67756)

[Nikita Popov via cfe-commits]

nikic wrote:

It looks like x86-bswap.c still has the C++ guarded code in it.

Any thoughts on

> Though I think we might be better off passing `-no-enable-noundef-analysis` to these tests, as noundef is really not what they want to test.

to avoid the test duplication?

https://github.com/llvm/llvm-project/pull/67756