[llvm-branch-commits] [llvm] [CGData] Refactor Global Merge Functions (PR #115750)

[Zhaoxuan Jiang via llvm-branch-commits]

nocchijiang wrote:

> I suspect that the no-LTO case might still encounter some slowdown, as each CU needs to read the entire CGData regardless.

I can confirm that the performance have been improved significantly from my testing on no-LTO projects that the slowdown is acceptable now. Before applying the PR it was about 50% slowdown, now it is ~5%.

> Alternatively, we could restructure the indexed CGData to allow for reading only the relevant hash entries on demand.

Besides only consuming the matched stable entries like what this PR does, this is exactly what I planned to do to reduce the memory footprint of the deserialized CGData. I would like to discuss the detail in the RFC thread with you to make sure that we are on the same page before coding it.


https://github.com/llvm/llvm-project/pull/115750