[clang] [llvm] [ThinLTO][Split] Split module for parallel compilation in backend (1/N) (PR #198702)

[Teresa Johnson via cfe-commits]

https://github.com/teresajohnson commented:

I started reviewing and have some high level questions and comments, and a number of other initial comments sprinkled throughout. Can you split this PR into 2? The first being the Utils support, llvm-split changes, and the associated llvm-split based tests; the second being the LTO support with some added LTO tests?

I know the callgraph based splitting is to avoid performance overhead from loss of IPO, but have you evaluated this?

https://github.com/llvm/llvm-project/pull/198702