Use empty() instead of comparing size() with zero.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@46514 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
index 250298e..293d023 100644
--- a/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/ScheduleDAG.cpp
@@ -230,7 +230,7 @@
 void ScheduleDAG::CalculateDepths() {
   std::vector<std::pair<SUnit*, unsigned> > WorkList;
   for (unsigned i = 0, e = SUnits.size(); i != e; ++i)
-    if (SUnits[i].Preds.size() == 0)
+    if (SUnits[i].Preds.empty())
       WorkList.push_back(std::make_pair(&SUnits[i], 0U));
 
   while (!WorkList.empty()) {