I don't see how NodeUpdated can be called with a

ReadyToProcess node - add an assertion to check
this.  Add an assertion to NodeDeleted that checks
that processed/ready nodes are indeed not deleted.
It is because they are never deleted that none of
the maps can have a deleted node as the source of
a mapping.  It does however seem to be possible in
theory to have a deleted value as the target of a
mapping, however this has not yet been spotted in
the wild.  Still mulling on what to do about this.
[The theoretical situation is this: a node A is
expanded/promoted/whatever to a newly created node
B.  Thus A->B is added to a map.  When the subtree
rooted at B is legalized it is conceivable that B
is deleted due to RAUW on a node somewhere above
it].

llvm-svn: 46705

1 files changed, 10 insertions, 5 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
index f09a311c064..3d419552826 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
@@ -220,22 +220,27 @@ void DAGTypeLegalizer::MarkNewNodes(SDNode *N) {
 namespace {
   /// NodeUpdateListener - This class is a DAGUpdateListener that listens for
   /// updates to nodes and recomputes their ready state.
-  class VISIBILITY_HIDDEN NodeUpdateListener : 
+  class VISIBILITY_HIDDEN NodeUpdateListener :
     public SelectionDAG::DAGUpdateListener {
     DAGTypeLegalizer &DTL;
   public:
     NodeUpdateListener(DAGTypeLegalizer &dtl) : DTL(dtl) {}
-    
+
     virtual void NodeDeleted(SDNode *N) {
       // Ignore deletes.
+      assert(N->getNodeId() != DAGTypeLegalizer::Processed &&
+             N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
+             "RAUW deleted processed node!");
     }
-    
+
     virtual void NodeUpdated(SDNode *N) {
       // Node updates can mean pretty much anything.  It is possible that an
       // operand was set to something already processed (f.e.) in which case
       // this node could become ready.  Recompute its flags.
-      if (N->getNodeId() != DAGTypeLegalizer::ReadyToProcess)
-        DTL.ReanalyzeNodeFlags(N);
+      assert(N->getNodeId() != DAGTypeLegalizer::Processed &&
+             N->getNodeId() != DAGTypeLegalizer::ReadyToProcess &&
+             "RAUW updated processed node!");
+      DTL.ReanalyzeNodeFlags(N);
     }
   };
 }