[PATCH] D18065: Fix bugs in the MemorySSA walker

[Daniel Berlin via llvm-commits]

dberlin added inline comments.

================
Comment at: lib/Transforms/Utils/MemorySSA.cpp:930
@@ +929,3 @@
+            break;
+
+          bool Backedge =
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I'm unclear why this makes sense. It tracks whether you've ever seen a backedge before hitting this phi.

If you see a backedge and move past that cycle, it will still trigger on the next cycle.

Honestly, this is also moving a bit far away from normal usage of the DFI iterator.
I am kinda wondering if we should not just turn this into the traditional SCC finding algorithm (treating the tuple of <thing, memorylocation> as the node we are visiting), and then we will know exactly which stuff is a cycle and which is not.



http://reviews.llvm.org/D18065