Fix ScheduleDAGRRList::CopyAndMoveSuccessors' handling of nodes
with multiple chain operands. This can occur when the scheduler
has added chain operands to a node that already has a chain
operand, in order to handle physical register dependencies.

This fixes an llvm-gcc bootstrap failure on x86-64 introduced
in r66058.

llvm-svn: 66240
diff --git a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
index a89564b..e505b7b 100644
--- a/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/ScheduleDAGRRList.cpp
@@ -410,7 +410,7 @@
       NewSU->isCommutable = true;
     ComputeLatency(NewSU);
 
-    SDep ChainPred;
+    SmallVector<SDep, 4> ChainPreds;
     SmallVector<SDep, 4> ChainSuccs;
     SmallVector<SDep, 4> LoadPreds;
     SmallVector<SDep, 4> NodePreds;
@@ -418,7 +418,7 @@
     for (SUnit::pred_iterator I = SU->Preds.begin(), E = SU->Preds.end();
          I != E; ++I) {
       if (I->isCtrl())
-        ChainPred = *I;
+        ChainPreds.push_back(*I);
       else if (I->getSUnit()->getNode() &&
                I->getSUnit()->getNode()->isOperandOf(LoadNode))
         LoadPreds.push_back(*I);
@@ -433,17 +433,17 @@
         NodeSuccs.push_back(*I);
     }
 
-    if (ChainPred.getSUnit()) {
-      RemovePred(SU, ChainPred);
+    for (unsigned i = 0, e = ChainPreds.size(); i != e; ++i) {
+      const SDep &Pred = ChainPreds[i];
+      RemovePred(SU, Pred);
       if (isNewLoad)
-        AddPred(LoadSU, ChainPred);
+        AddPred(LoadSU, Pred);
     }
     for (unsigned i = 0, e = LoadPreds.size(); i != e; ++i) {
       const SDep &Pred = LoadPreds[i];
       RemovePred(SU, Pred);
-      if (isNewLoad) {
+      if (isNewLoad)
         AddPred(LoadSU, Pred);
-      }
     }
     for (unsigned i = 0, e = NodePreds.size(); i != e; ++i) {
       const SDep &Pred = NodePreds[i];