[llvm] r352784 - [DAG] Aggressively cleanup dangling node in CombineZExtLogicopShiftLoad.

[Nirav Dave via llvm-commits]

Author: niravd
Date: Thu Jan 31 11:35:14 2019
New Revision: 352784

URL: http://llvm.org/viewvc/llvm-project?rev=352784&view=rev
Log:
[DAG] Aggressively cleanup dangling node in CombineZExtLogicopShiftLoad.

While dangling nodes will eventually be pruned when they are
considered, leaving them disables combines requiring single-use.

Reviewers: Carrot, spatel, craig.topper, RKSimon, efriedma

Subscribers: hiraditya, llvm-commits

Differential Revision: https://reviews.llvm.org/D57520

Modified:
    llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

Modified: llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp?rev=352784&r1=352783&r2=352784&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/DAGCombiner.cpp Thu Jan 31 11:35:14 2019
@@ -8465,6 +8465,10 @@ SDValue DAGCombiner::CombineZExtLogicopS
                                 Load->getValueType(0), ExtLoad);
     CombineTo(Load, Trunc, ExtLoad.getValue(1));
   }
+
+  // N0 is dead at this point.
+  recursivelyDeleteUnusedNodes(N0.getNode());
+
   return SDValue(N,0); // Return N so it doesn't get rechecked!
 }