[PATCH] D92385: [ARM] Add a pass that re-arranges blocks when there is a backwards WLS branch

[Sam Tebbs via Phabricator via llvm-commits]

samtebbs added inline comments.


================
Comment at: llvm/lib/Target/ARM/ARMBlockPlacement.cpp:213
+  // Fix fall-through to the moved BB from the one that used to be before it
+  if (BBPrevious && BBPrevious->isSuccessor(BB))
+    FixFallthrough(BBPrevious, BB);
----------------
SjoerdMeijer wrote:
> I guess `BBPrevious` is a nullptr when the WLS is in the Entry block? Is this covered with a test? I guess that will never happen, so we will always fix this fall through, and never skip over which is then not covered by a test.
> I am not even sure that makes sense, i.e. the WLS in the entry block, because then we would move the entry block. So, does this need to be an assert that BBprevious is not a nullptr?
I could make it an assertion and make sure it isn't the entry block in the main loop.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D92385/new/

https://reviews.llvm.org/D92385