Use SmallVectorImpl instead of SmallVector for iterators and references to avoid specifying the vector size unnecessarily.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185512 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/ScheduleDAG.cpp b/lib/CodeGen/ScheduleDAG.cpp
index 07e5b47..75e3790 100644
--- a/lib/CodeGen/ScheduleDAG.cpp
+++ b/lib/CodeGen/ScheduleDAG.cpp
@@ -64,8 +64,8 @@
 /// specified node.
 bool SUnit::addPred(const SDep &D, bool Required) {
   // If this node already has this depenence, don't add a redundant one.
-  for (SmallVector<SDep, 4>::iterator I = Preds.begin(), E = Preds.end();
-       I != E; ++I) {
+  for (SmallVectorImpl<SDep>::iterator I = Preds.begin(), E = Preds.end();
+         I != E; ++I) {
     // Zero-latency weak edges may be added purely for heuristic ordering. Don't
     // add them if another kind of edge already exists.
     if (!Required && I->getSUnit() == D.getSUnit())
@@ -77,7 +77,7 @@
         // Find the corresponding successor in N.
         SDep ForwardD = *I;
         ForwardD.setSUnit(this);
-        for (SmallVector<SDep, 4>::iterator II = PredSU->Succs.begin(),
+        for (SmallVectorImpl<SDep>::iterator II = PredSU->Succs.begin(),
                EE = PredSU->Succs.end(); II != EE; ++II) {
           if (*II == ForwardD) {
             II->setLatency(D.getLatency());
@@ -132,8 +132,8 @@
 /// the specified node.
 void SUnit::removePred(const SDep &D) {
   // Find the matching predecessor.
-  for (SmallVector<SDep, 4>::iterator I = Preds.begin(), E = Preds.end();
-       I != E; ++I)
+  for (SmallVectorImpl<SDep>::iterator I = Preds.begin(), E = Preds.end();
+         I != E; ++I)
     if (*I == D) {
       // Find the corresponding successor in N.
       SDep P = D;