[llvm] [LLVM] Refactor Autoupgrade function attributes from Module attributes. (PR #84494)

[Daniel Kiss via llvm-commits]

DanielKristofKiss wrote:

> So I think @dhoekwater and @pranavk have pointed out where the suspected reported regression may have come from in the base commit.

If you have something that I can reproduce I'd try to debug it too.
 
> What happens when a module never had these module level metadata set? There's a difference between `"sign-return-address"=0` and `<nothing>`. They suspect what's happening is that modules with are being linked against other modules, which is then setting `sign-return-address="false"` on the second module, which is now no longer being inlined.

All module goes thru here so we should not have mix of `"sign-return-address"=0` and `<nothing>` in the merged module.



https://github.com/llvm/llvm-project/pull/84494