SDAG: Remove OPC_MarkGlueResults and associated logic. NFC

This opcode never happens in practice, and yet the logic we have in
place to handle it would be undefined behaviour if we ever executed
it. Remove it rather than trying to refactor code that's never
reached.

llvm-svn: 268692

1 files changed, 19 insertions, 60 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index d6b737dce9f..f37cc6f519a 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -2162,14 +2162,11 @@ GetVBR(uint64_t Val, const unsigned char *MatcherTable, unsigned &Idx) {
   return Val;
 }
 
-/// UpdateChainsAndGlue - When a match is complete, this method updates uses of
-/// interior glue and chain results to use the new glue and chain results.
-void SelectionDAGISel::
-UpdateChainsAndGlue(SDNode *NodeToMatch, SDValue InputChain,
-                    const SmallVectorImpl<SDNode*> &ChainNodesMatched,
-                    SDValue InputGlue,
-                    const SmallVectorImpl<SDNode*> &GlueResultNodesMatched,
-                    bool isMorphNodeTo) {
+/// When a match is complete, this method updates uses of interior chain results
+/// to use the new results.
+void SelectionDAGISel::UpdateChains(
+    SDNode *NodeToMatch, SDValue InputChain,
+    const SmallVectorImpl<SDNode *> &ChainNodesMatched, bool isMorphNodeTo) {
   SmallVector<SDNode*, 4> NowDeadNodes;
 
   // Now that all the normal results are replaced, we replace the chain and
@@ -2204,29 +2201,6 @@ UpdateChainsAndGlue(SDNode *NodeToMatch, SDValue InputChain,
     }
   }
 
-  // If the result produces glue, update any glue results in the matched
-  // pattern with the glue result.
-  if (InputGlue.getNode()) {
-    // Handle any interior nodes explicitly marked.
-    for (unsigned i = 0, e = GlueResultNodesMatched.size(); i != e; ++i) {
-      SDNode *FRN = GlueResultNodesMatched[i];
-
-      // If this node was already deleted, don't look at it.
-      if (FRN->getOpcode() == ISD::DELETED_NODE)
-        continue;
-
-      assert(FRN->getValueType(FRN->getNumValues()-1) == MVT::Glue &&
-             "Doesn't have a glue result");
-      CurDAG->ReplaceAllUsesOfValueWith(SDValue(FRN, FRN->getNumValues()-1),
-                                        InputGlue);
-
-      // If the node became dead and we haven't already seen it, delete it.
-      if (FRN->use_empty() &&
-          !std::count(NowDeadNodes.begin(), NowDeadNodes.end(), FRN))
-        NowDeadNodes.push_back(FRN);
-    }
-  }
-
   if (!NowDeadNodes.empty())
     CurDAG->RemoveDeadNodes(NowDeadNodes);
 
@@ -2707,7 +2681,7 @@ struct MatchScope {
   SDValue InputChain, InputGlue;
 
   /// HasChainNodesMatched - True if the ChainNodesMatched list is non-empty.
-  bool HasChainNodesMatched, HasGlueResultNodesMatched;
+  bool HasChainNodesMatched;
 };
 
 /// \\brief A DAG update listener to keep the matching state
@@ -2820,7 +2794,6 @@ SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
   // which ones they are.  The result is captured into this list so that we can
   // update the chain results when the pattern is complete.
   SmallVector<SDNode*, 3> ChainNodesMatched;
-  SmallVector<SDNode*, 3> GlueResultNodesMatched;
 
   DEBUG(dbgs() << "ISEL: Starting pattern match on root node: ";
         NodeToMatch->dump(CurDAG);
@@ -2926,7 +2899,6 @@ SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
       NewEntry.InputChain = InputChain;
       NewEntry.InputGlue = InputGlue;
       NewEntry.HasChainNodesMatched = !ChainNodesMatched.empty();
-      NewEntry.HasGlueResultNodesMatched = !GlueResultNodesMatched.empty();
       MatchScopes.push_back(NewEntry);
       continue;
     }
@@ -3469,29 +3441,13 @@ SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
 
       // If this was a MorphNodeTo then we're completely done!
       if (IsMorphNodeTo) {
-        // Update chain and glue uses.
-        UpdateChainsAndGlue(NodeToMatch, InputChain, ChainNodesMatched,
-                            InputGlue, GlueResultNodesMatched, true);
+        // Update chain uses.
+        UpdateChains(NodeToMatch, InputChain, ChainNodesMatched, true);
         return Res;
       }
       continue;
     }
 
-    case OPC_MarkGlueResults: {
-      unsigned NumNodes = MatcherTable[MatcherIndex++];
-
-      // Read and remember all the glue-result nodes.
-      for (unsigned i = 0; i != NumNodes; ++i) {
-        unsigned RecNo = MatcherTable[MatcherIndex++];
-        if (RecNo & 128)
-          RecNo = GetVBR(RecNo, MatcherTable, MatcherIndex);
-
-        assert(RecNo < RecordedNodes.size() && "Invalid MarkGlueResults");
-        GlueResultNodesMatched.push_back(RecordedNodes[RecNo].first.getNode());
-      }
-      continue;
-    }
-
     case OPC_CompleteMatch: {
       // The match has been completed, and any new nodes (if any) have been
       // created.  Patch up references to the matched dag to use the newly
@@ -3519,13 +3475,18 @@ SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
         CurDAG->ReplaceAllUsesOfValueWith(SDValue(NodeToMatch, i), Res);
       }
 
-      // If the root node defines glue, add it to the glue nodes to update list.
-      if (NodeToMatch->getValueType(NodeToMatch->getNumValues()-1) == MVT::Glue)
-        GlueResultNodesMatched.push_back(NodeToMatch);
+      // Update chain uses.
+      UpdateChains(NodeToMatch, InputChain, ChainNodesMatched, false);
 
-      // Update chain and glue uses.
-      UpdateChainsAndGlue(NodeToMatch, InputChain, ChainNodesMatched,
-                          InputGlue, GlueResultNodesMatched, false);
+      // If the root node defines glue, we need to update it to the glue result.
+      // TODO: This never happens in our tests and I think it can be removed /
+      // replaced with an assert, but if we do it this the way the change is
+      // NFC.
+      if (NodeToMatch->getValueType(NodeToMatch->getNumValues() - 1) ==
+              MVT::Glue &&
+          InputGlue.getNode())
+        CurDAG->ReplaceAllUsesOfValueWith(
+            SDValue(NodeToMatch, NodeToMatch->getNumValues() - 1), InputGlue);
 
       assert(NodeToMatch->use_empty() &&
              "Didn't replace all uses of the node?");
@@ -3565,8 +3526,6 @@ SelectCodeCommon(SDNode *NodeToMatch, const unsigned char *MatcherTable,
       InputGlue = LastScope.InputGlue;
       if (!LastScope.HasChainNodesMatched)
         ChainNodesMatched.clear();
-      if (!LastScope.HasGlueResultNodesMatched)
-        GlueResultNodesMatched.clear();
 
       // Check to see what the offset is at the new MatcherIndex.  If it is zero
       // we have reached the end of this scope, otherwise we have another child