Avoid referring to edge D after the Succs or Preds arrays have
been modified, to avoid trouble in the (unlikely) scenario that
D is a reference to an element in one of those arrays.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62173 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAG.cpp b/lib/CodeGen/ScheduleDAG.cpp
index 730080d..62b816c 100644
--- a/lib/CodeGen/ScheduleDAG.cpp
+++ b/lib/CodeGen/ScheduleDAG.cpp
@@ -75,8 +75,8 @@
     ++NumPredsLeft;
   if (!isScheduled)
     ++N->NumSuccsLeft;
-  N->Succs.push_back(P);
   Preds.push_back(D);
+  N->Succs.push_back(P);
   if (P.getLatency() != 0) {
     this->setDepthDirty();
     N->setHeightDirty();
@@ -105,8 +105,8 @@
         }
       assert(FoundSucc && "Mismatching preds / succs lists!");
       Preds.erase(I);
-      // Update the bookkeeping;
-      if (D.getKind() == SDep::Data) {
+      // Update the bookkeeping.
+      if (P.getKind() == SDep::Data) {
         --NumPreds;
         --N->NumSuccs;
       }