[PATCH] D96780: [NPM][LTO] Update buildLTODefaultPipeline to be more in-line with the old pass manager

[Dave Green via Phabricator via llvm-commits]

dmgreen added a comment.

In D96780#2566399 <https://reviews.llvm.org/D96780#2566399>, @ychen wrote:

> It would be great to have some compile-time impact data before landing (https://llvm-compile-time-tracker.com/, clang self-host, etc.). This also depends on the potential performance gain on average. Just want to make sure we make the appropriate tradeoff.

"1350%" :)

This is only trying to get us back to where we were before, before all the regressions from the new pass manager. Whilst I can agree that compile time is important, this was a pretty significant set of regressions for us. Even if it is a compile time increase, the results I'm seeing would easily make it worth-while! The only real alternative is that we revert c70737b <https://reviews.llvm.org/rGc70737ba1dea947350879a4f53a4a5513d6c9252> again until this can be fixed (which I was hoping not to have to do).


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