Since D76871 it is sufficient to run `opt -atributor` or `-attributor-cgscc`.
This patch is based on D63312 and D63319. For now we create shallow wrappers for all functions that are IPO amendable. See also [this github issue](https://github.com/llvm/llvm-project/issues/172). Reviewed By: jdoerfert Differential Revision: https://reviews.llvm.org/D76404