[llvm-branch-commits] [llvm] release/20.x: [IR] Fix assertion error in User new/delete edge case (#129914) (PR #130580)

[Nikita Popov via llvm-branch-commits]

https://github.com/nikic approved this pull request.

I think this is okay to backport. We should do this properly on main, but this is probably the more conservative fix.

https://github.com/llvm/llvm-project/pull/130580