[PATCH] D59153: [MBP] Make sure the exit BB is the most possible successor before rotating a loop

[Guozhi Wei via Phabricator via llvm-commits]

Carrot marked an inline comment as done.
Carrot added inline comments.


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Comment at: lib/CodeGen/MachineBlockPlacement.cpp:1871
+bool
+MachineBlockPlacement::isBestPred(const MachineBasicBlock *Succ,
+                                  const MachineBasicBlock *MBB) {
----------------
davidxl wrote:
> loop rotation can save one internal fall through, not just adding a loop exit fall through. Do you need to consider the overall cost/savings?
If MBB is not the best predecessor of Succ, then Succ will not be placed after MBB, the overall cost saving should not consider MBB -> Succ.


Repository:
  rL LLVM

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  https://reviews.llvm.org/D59153/new/

https://reviews.llvm.org/D59153