[PATCH] D29376: LTO: align the Monolithic LTO optimization pipeline on the ThinLTO and O2/O3 one

[Davide Italiano via Phabricator via llvm-commits]

davide added a comment.

I took some time to run on some games internally. The change is mostly performance neutral, some titles are 1% faster, some 1% slower, but nothing glamorous. 
(Please note these are "real-world" programs, not synthetic benchmarks). 
What worries me about this change is the increase in compile time. I was able to notice 30%-50% increase in compile time (for some of these, the LTO time was already 10 minutes so 50% more is not acceptable). 
The time is spent in the usual suspects: GVN, InstCombine, Inlining etc... I'd love to hear others' thoughts, but I'm inclined to hold on this until we have a better story for our compile time.


https://reviews.llvm.org/D29376