[clang] [llvm] Allow Custom LTO Linking And Fix Warp Sizes (PR #224691)

[Teresa Johnson via llvm-commits]

teresajohnson wrote:

Sort of echoing some of the prior comments. There seem to be a bunch of disjointed changes in the PR, and not much in the way of tests. Also a ton of cl::opt added but some (most?) aren't used in the PR. Can you clean this up and send separate PRs for different types of changes with associated tests? I'm also unsure of why the new CustomLTO is needed - right now it seems to map to the default LTO backend. I think an RFC with what is planned there would be helpful.

https://github.com/llvm/llvm-project/pull/224691