Fix SelectionDAG compile time issue with alias analysis.
Add new token factor node and its users to worklist if alias analysis is
turned on, in DAGCombiner::visitTokenFactor(). Alias analysis may cause
a lot of new token factors to be inserted into the DAG, and they need to
be optimized to avoid significant slow-downs.
Reviewed by Hal Finkel.
llvm-svn: 228841
diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index cc7388b..c8b723a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -1540,8 +1540,11 @@
Result = DAG.getNode(ISD::TokenFactor, SDLoc(N), MVT::Other, Ops);
}
- // Don't add users to work list.
- return CombineTo(N, Result, false);
+ // Add users to worklist if AA is enabled, since it may introduce
+ // a lot of new chained token factors while removing memory deps.
+ bool UseAA = CombinerAA.getNumOccurrences() > 0 ? CombinerAA
+ : DAG.getSubtarget().useAA();
+ return CombineTo(N, Result, UseAA /*add to worklist*/);
}
return Result;