Propagate DAG node ordering during type legalization and instruction selection

A node's ordering is only propagated during legalization if (a) the new node does
not have an ordering (is not a CSE'd node), or (b) the new node has an ordering
that is higher than the node being legalized.

llvm-svn: 177465

1 files changed, 3 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
index c3b6276a8dc..15001f506b0 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGISel.cpp
@@ -785,8 +785,10 @@ void SelectionDAGISel::DoInstructionSelection() {
       if (ResNode == Node || Node->getOpcode() == ISD::DELETED_NODE)
         continue;
       // Replace node.
-      if (ResNode)
+      if (ResNode) {
+        CurDAG->AssignOrdering(ResNode, CurDAG->GetOrdering(Node));
         ReplaceUses(Node, ResNode);
+      }
 
       // If after the replacement this node is not used any more,
       // remove this dead node.