[PATCH] D156235: [MachineBlockPlacement] Remove the pad limit for no-fallthrough loops

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


================
Comment at: llvm/lib/CodeGen/MachineBlockPlacement.cpp:2954
+      if (MaxBytesForAlignmentOverride.getNumOccurrences() == 0
+        && (ChainBB == LoopHeader || MLI->getLoopFor(LayoutPred) != L))
+        ChainBB->setAlignment(Align, 0);
----------------
The `!LayoutPred->isSuccessor(ChainBB)` check already ensures the padding will never be executed.  Given that, I guess the remaining checks here are to try to maximize icache hits.  In that context, why are loop headers special?  Do we care if LayoutPred is part of a subloop of L?


CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D156235/new/

https://reviews.llvm.org/D156235