[PATCH] D48278: [SelectionDAG] Fold redundant masking operations of shifted value

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: lib/CodeGen/SelectionDAG/DAGCombiner.cpp:5986
+  const auto &MaskedValue = dyn_cast<SDNode>(MASKED);
+  for (SDNode *OtherUser : MaskedValue->uses()) {
+    if ((&(*OtherUser) == ShiftAmount) || (OtherUser->getOpcode() != ISD::AND))
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Walking the uses of an SDNode can get expensive... is this O(N^2) in the number of uses of MaskedValue?  If not, please add a comment explaining why it isn't.


https://reviews.llvm.org/D48278