[clang] [lld] [llvm] [ThinLTO] Reduce the number of renaming due to promotions (PR #178587)

[via cfe-commits]

yonghong-song wrote:

Just uploaded another version to fix the test
   reduce-promotion-same-local-name-distributed.ll
by adding `-force-import-all` to llvm-lto2 command line.

So looks like for DTLTO and WriteIndexesOnly, ForceImportAll is needed. And for InProcess mode, ForceImportAll is not needed. Do we have a way to distinguish them in LTO.cpp? Or we have to use ForceImportAll for all of them? Or any other alternatives?

https://github.com/llvm/llvm-project/pull/178587