[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp

[Chris Lattner]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

SelectionDAGISel.cpp updated: 1.94 -> 1.95
---
Log message:

Avoid creating a token factor node in trivially redundant cases.  This
eliminates almost one node per block in common cases.


---
Diffs of the changes:  (+12 -1)

 SelectionDAGISel.cpp |   13 ++++++++++++-
 1 files changed, 12 insertions(+), 1 deletion(-)


Index: llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1.94 llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1.95
--- llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp:1.94	Tue Nov  8 22:45:33 2005
+++ llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp	Tue Nov  8 23:03:03 2005
@@ -1234,7 +1234,18 @@
 
   // Turn all of the unordered chains into one factored node.
   if (!UnorderedChains.empty()) {
-    UnorderedChains.push_back(SDL.getRoot());
+    SDOperand Root = SDL.getRoot();
+    if (Root.getOpcode() != ISD::EntryToken) {
+      unsigned i = 0, e = UnorderedChains.size();
+      for (; i != e; ++i) {
+        assert(UnorderedChains[i].Val->getNumOperands() > 1);
+        if (UnorderedChains[i].Val->getOperand(0) == Root)
+          break;  // Don't add the root if we already indirectly depend on it.
+      }
+        
+      if (i == e)
+        UnorderedChains.push_back(Root);
+    }
     DAG.setRoot(DAG.getNode(ISD::TokenFactor, MVT::Other, UnorderedChains));
   }