[PATCH] D46404: [DAG] Avoid using deleted node in rebuildSetCC

[Eli Friedman via Phabricator via llvm-commits]

efriedma added inline comments.


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Comment at: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:11511
+        N = Tmp;
+    }
 
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This needs a much better comment explaining what we're doing, and why; normally the DAGCombine visitors are not supposed to call each other (because it causes weird issues like this).

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And actually, I'm not sure why we're calling visitXOR here in the first place; if we're missing some important optimization on xors, we should probably fix the setcc optimizations to do the same thing rather than try to delay the xor->setcc transform.  But I won't ask you to change that here; I don't want to delay the bugfix.


Repository:
  rL LLVM

https://reviews.llvm.org/D46404