[PATCH] D35609: [LICM] Make sinkRegion and hoistRegion non-recursive

[Sanjoy Das via Phabricator via llvm-commits]

sanjoy added inline comments.


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Comment at: lib/Transforms/Scalar/LICM.cpp:348
+  SmallVector<BasicBlock *, 16> Worklist;
+  DT->getDescendants(N->getBlock(), Worklist);
 
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`getDescendants` seems to be doing a BFS.  Given that (and that DT is a tree), can you iterate `Worklist` in reverse to get a post order?  If you do this, we'd have to spec `getDescendants` as doing a BFS though (and not just have it be an implementation detail).

OTOH if you write the BFS by hand (instead of relying on `getDescendents`), you can add an early exit for `CurLoop->contains(BB)`.


https://reviews.llvm.org/D35609