[PATCH] D48102: Improve handling of COPY instructions with identical value numbers

[Tim Renouf via Phabricator via llvm-commits]

tpr added a comment.

This "in the way" def at 816r is an implicit_def that is also being erased. I think this has to be the case, otherwise the main range would not have set our def as CR_Erase Identical, and/or the main range would not have allowed coalescing at all.

Therefore I now think the fix for this problem is to do all the prunes first, remembering the end points, and then do the extend afterwards.

I have a local fix for that which I will now start testing.


Repository:
  rL LLVM

https://reviews.llvm.org/D48102