[PATCH] D62079: [MBP] Rotate should bring more fallthrough

[David Li via Phabricator via llvm-commits]

davidxl added a comment.

Loop rotation not only affects fall through placement of incoming and exit edges, but internal fall through as well -- it converts the original backedge into a new fallthrough while converts an original internal fallthrough into the backedge.   In other words, the overall cost/benefit needs to consider all changes. Doing pattern matching like this can lead to wrong decisions.

I assume this case can be handled by your next complete patch, so we should try to go that direction directly.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D62079/new/

https://reviews.llvm.org/D62079