[llvm] [RFC] [IR] Modules can make filtered range to iterate function definitions only (PR #167972)

[Nikita Popov via llvm-commits]

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

LGTM. I think `function_defs()` instead of `getFunctionDefs()` would be more in line with the naming convention of range iterators in LLVM, but I don't feel strongly about it.

https://github.com/llvm/llvm-project/pull/167972