[PATCH] D148010: [Pipelines] Don't run module optimization in full LTO pre-link

[Nikita Popov via Phabricator via llvm-commits]

nikic added a comment.

In D148010#4258487 <https://reviews.llvm.org/D148010#4258487>, @dmgreen wrote:

> I would be very surprised if this didn't cause some large regressions.

In theory this should be an improvement on both compile-time and performance. In practice, theory and practice probably don't match and this will be a mixed bag in terms of performance.

> I've always thought that one of the benefits for LTO is not just that it combines all function into a single module, but that it runs the pass pipeline twice.

This is not an intended benefit of LTO, but it's indeed pretty plausible that LTO can paper over phase ordering issues.

I'd appreciate any help in evaluating performance for this change.


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https://reviews.llvm.org/D148010