diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 14bfe0d..10b5c74 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6402,9 +6402,8 @@
   BasicBlock *Header = L->getHeader();
 
   // Push all Loop-header PHIs onto the Worklist stack.
-  for (BasicBlock::iterator I = Header->begin();
-       PHINode *PN = dyn_cast<PHINode>(I); ++I)
-    Worklist.push_back(PN);
+  for (PHINode &PN : Header->phis())
+    Worklist.push_back(&PN);
 }
 
 const ScalarEvolution::BackedgeTakenInfo &
@@ -7638,12 +7637,9 @@
   if (!Latch)
     return nullptr;
 
-  for (auto &I : *Header) {
-    PHINode *PHI = dyn_cast<PHINode>(&I);
-    if (!PHI) break;
-    auto *StartCST = getOtherIncomingValue(PHI, Latch);
-    if (!StartCST) continue;
-    CurrentIterVals[PHI] = StartCST;
+  for (PHINode &PHI : Header->phis()) {
+    if (auto *StartCST = getOtherIncomingValue(&PHI, Latch))
+      CurrentIterVals[&PHI] = StartCST;
   }
   if (!CurrentIterVals.count(PN))
     return RetVal = nullptr;
@@ -7720,13 +7716,9 @@
   BasicBlock *Latch = L->getLoopLatch();
   assert(Latch && "Should follow from NumIncomingValues == 2!");
 
-  for (auto &I : *Header) {
-    PHINode *PHI = dyn_cast<PHINode>(&I);
-    if (!PHI)
-      break;
-    auto *StartCST = getOtherIncomingValue(PHI, Latch);
-    if (!StartCST) continue;
-    CurrentIterVals[PHI] = StartCST;
+  for (PHINode &PHI : Header->phis()) {
+    if (auto *StartCST = getOtherIncomingValue(&PHI, Latch))
+      CurrentIterVals[&PHI] = StartCST;
   }
   if (!CurrentIterVals.count(PN))
     return getCouldNotCompute();