[PATCH] D65376: Randomly outline code for cold regions

[Aditya Kumar via Phabricator via llvm-commits]

hiraditya added a comment.

> As a future direction for code reordering in llvm, a pass that operates on the machine instruction level may have more promise. At that level, there's a reduced/eliminated code size penalty and landingpads can be moved easily. There's less pass ordering flexibility, but experiments seem to show that late splitting works better anyway.

Agree with the reasoning here, probably that's why all previous hot-cold splitting were done at the RTL level. The problem with having machine-level passes like these are related to porting the optimization to every backend and maintenance. In my experience, even when they don't give the optimal results IR level passes scale well.


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  https://reviews.llvm.org/D65376/new/

https://reviews.llvm.org/D65376