[PATCH] D47816: [InstCombine] Don't sink instructions across inlined function call.

[Renlin Li via Phabricator via llvm-commits]

renlin added a comment.

I agree that, generally it is not a good idea to sink across function call. I am a little bit consecutive on this change.

Thank you for your suggestion. I checked the document about TTI::isLoweredToCall. 
IIUIC, it seems to me this backend information is still not strong enough.

- If the backend returns false for a function, it will get expanded by some passes somewhere in the optimization pipeline. This might complicated the CFG, similar as the inlined function cases.
- If the backend returns true for a function, it is an real function call. This will extend the live-range of related variables.

Should we just stop sinking instructions across any type of function call?
Normally, InstCombine will be called multiple time, if a function got expanded, we still have opportunities to sink instructions when it is beneficial.


Repository:
  rL LLVM

https://reviews.llvm.org/D47816