Fix a bug Sabre was having where the DAG root was a group.  The group dominator
needed to be added to the ordering list, not the first member of the group.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@24816 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
index ef90fc0..03a0dd1 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
@@ -682,7 +682,12 @@
 /// Note that the ordering in the Nodes vector is reversed.
 void SimpleSched::VisitAll() {
   // Add first element to list
-  Ordering.push_back(getNI(DAG.getRoot().Val));
+  NodeInfo *NI = getNI(DAG.getRoot().Val);
+  if (NI->isInGroup()) {
+    Ordering.push_back(NI->Group->getDominator());
+  } else {
+    Ordering.push_back(NI);
+  }
   
   // Iterate through all nodes that have been added
   for (unsigned i = 0; i < Ordering.size(); i++) { // note: size() varies