[PATCH] D90115: [LoopDeletion] Remove dead loops with no exit blocks

[Johannes Doerfert via Phabricator via llvm-commits]

jdoerfert accepted this revision.
jdoerfert added a comment.
This revision is now accepted and ready to land.

LGTM, a few nits to be addressed prior to the merge.



================
Comment at: llvm/include/llvm/Analysis/LoopInfoImpl.h:75
+  getExitBlocks(UniqueExitBlocks);
+  return UniqueExitBlocks.empty();
+}
----------------
-Unique


================
Comment at: llvm/lib/Transforms/Scalar/LoopDeletion.cpp:200
+    LLVM_DEBUG(
+        dbgs() << "Deletion requires single exit block or no exit blocks\n");
     return LoopDeletionResult::Unmodified;
----------------
Nit: aka, at most one exit block ;)


================
Comment at: llvm/lib/Transforms/Utils/LoopUtils.cpp:685
       DeadDebugInst.push_back(DVI);
     }
 
----------------
Assuming the only use of the DeadDebugInst vector is the code blow that we don't execute (no point to "move" the stuff to), this entire loop is useless for the no-exit case.

Line 668 is trivially true for the no-exit case and 677-684 not needed as described above.

Thus, move the if(ExitBlock) to 648.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D90115/new/

https://reviews.llvm.org/D90115