[PATCH] D58070: [DAGCombine] Prune unnused nodes.

[James Y Knight via Phabricator via llvm-commits]

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

It'd be nice if we knew why adding new nodes to the worklist seemed to cause an issue, but the reduced form as here seems okay as far as it goes.



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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:696-697
 
-  // This should eventually be pruning.
-  void NodeInserted(SDNode *N) override { }
+  // FIXME: Ideally we could add N to the worklist, but this causes exponential
+  //        compile time costs in large DAGs, e.g. Halide.
+  void NodeInserted(SDNode *N) override { DC.ConsiderForPruning(N); }
----------------
Might be infinite loop, not exponential time?


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