diff --git a/llvm/lib/IR/LegacyPassManager.cpp b/llvm/lib/IR/LegacyPassManager.cpp
index 8fd35ef975e2c1..544c56a789a3ac 100644
--- a/llvm/lib/IR/LegacyPassManager.cpp
+++ b/llvm/lib/IR/LegacyPassManager.cpp
@@ -685,16 +685,12 @@ PMTopLevelManager::setLastUser(ArrayRef<Pass*> AnalysisPasses, Pass *P) {
 /// Collect passes whose last user is P
 void PMTopLevelManager::collectLastUses(SmallVectorImpl<Pass *> &LastUses,
                                         Pass *P) {
-  DenseMap<Pass *, SmallPtrSet<Pass *, 8> >::iterator DMI =
-    InversedLastUser.find(P);
+  auto DMI = InversedLastUser.find(P);
   if (DMI == InversedLastUser.end())
     return;
 
-  SmallPtrSet<Pass *, 8> &LU = DMI->second;
-  for (Pass *LUP : LU) {
-    LastUses.push_back(LUP);
-  }
-
+  auto &LU = DMI->second;
+  LastUses.append(LU.begin(), LU.end());
 }
 
 AnalysisUsage *PMTopLevelManager::findAnalysisUsage(Pass *P) {