[PATCH] D63972: [CodeGen] Do the Simple Early Return in block-placement pass to optimize the blocks

[Eli Friedman via Phabricator via llvm-commits]

efriedma added a comment.

Can you remove the dead `MachineDominatorTree *MDT;` declaration?

> the function MachineBlockPlacement::runOnMachineFunction will do some clean work and will never use the MachinePostDominatorTree info, and this pass don't preserve the MachinePostDominatorTree

Please add this explanation as an explicit comment in the code.


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D63972/new/

https://reviews.llvm.org/D63972