[llvm-commits] [llvm] r46705 - /llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp

Duncan Sands baldrick at free.fr
Mon Feb 4 01:29:18 PST 2008

Author: baldrick
Date: Mon Feb  4 03:29:17 2008
New Revision: 46705

URL: http://llvm.org/viewvc/llvm-project?rev=46705&view=rev
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


Modified: llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp?rev=46705&r1=46704&r2=46705&view=diff

--- llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp (original)
+++ llvm/trunk/lib/CodeGen/SelectionDAG/LegalizeTypes.cpp Mon Feb  4 03:29:17 2008
@@ -220,22 +220,27 @@
 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;
     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);

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