[PATCH] D46756: [AMDGPU] Reworked SIFixWWMLiveness

[Tim Renouf via Phabricator via llvm-commits]

tpr added a comment.

Hi Daniel

Thanks for the comments. The LCSSA thing sounds good, except it does not overcome Nicolai's objection to relying on LoopInfo for semantic correctness.

I guess it might be possible to find the loop-exiting values as a def that reaches itself and has at least one use that does not reach the def.

Remember that all of this still has the fatal flaw that the register allocator may split a register and completely negate our attempts to add artificial liveness.


Repository:
  rL LLVM

https://reviews.llvm.org/D46756