[llvm] Reapply [TLI] Fix replace-with-veclib crash with invalid arguments (PR #77945)

[Maciej Gabka via llvm-commits]

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

The change in the CMakeLists looks reasonable, and the rest of the patch has already been reviewed.

https://github.com/llvm/llvm-project/pull/77945