Switch more loops to be range-based

This makes the code a little more concise, no functional change is
intended.

llvm-svn: 273644
diff --git a/llvm/lib/Transforms/Utils/MemorySSA.cpp b/llvm/lib/Transforms/Utils/MemorySSA.cpp
index a52ea34..7cff51e 100644
--- a/llvm/lib/Transforms/Utils/MemorySSA.cpp
+++ b/llvm/lib/Transforms/Utils/MemorySSA.cpp
@@ -469,10 +469,9 @@
     auto It = PerBlockAccesses.find(CurrNode->getBlock());
     if (It != PerBlockAccesses.end()) {
       auto &Accesses = It->second;
-      for (auto RAI = Accesses->rbegin(), RAE = Accesses->rend(); RAI != RAE;
-           ++RAI) {
-        if (isa<MemoryDef>(*RAI) || isa<MemoryPhi>(*RAI))
-          return &*RAI;
+      for (MemoryAccess &RA : reverse(*Accesses)) {
+        if (isa<MemoryDef>(RA) || isa<MemoryPhi>(RA))
+          return &RA;
       }
     }
     CurrNode = CurrNode->getIDom();