[PATCH] D43620: [Pipeliner] Fixed node order issue related to zero latency edges

[Danila Malyutin via Phabricator via llvm-commits]

danilaml added a comment.
Herald added a project: LLVM.

Sorry for commenting on an old merge PR, but was looking through some asserts and stumbled on this code which raised some questions.



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Comment at: llvm/trunk/lib/CodeGen/MachinePipeliner.cpp:3908
+  typedef std::pair<SUnit *, unsigned> UnitIndex;
+  std::vector<UnitIndex> Indices(NodeOrder.size(), std::make_pair(nullptr, 0));
+
----------------
Why Indicies is initialized with NodeOrder.size() {nullptr, 0} pairs? Are they used anywhere?


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Comment at: llvm/trunk/lib/CodeGen/MachinePipeliner.cpp:3951
+      unsigned SuccIndex =
+          std::get<1>(*std::lower_bound(Indices.begin(), Indices.end(),
+                                        std::make_pair(SuccSU, 0), CompareKey));
----------------
Is this dereference always valid? Can SuccSU unit be exit su and not be part of the NodeOrder?


Repository:
  rL LLVM

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  https://reviews.llvm.org/D43620/new/

https://reviews.llvm.org/D43620