Replace some explicit compare loops with std::equal.

No functionality change.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@160501 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/IPO/ArgumentPromotion.cpp b/lib/Transforms/IPO/ArgumentPromotion.cpp
index 95a3b3d..b94dd69 100644
--- a/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -245,10 +245,7 @@
                      const ArgPromotion::IndicesVector &Longer) {
   if (Prefix.size() > Longer.size())
     return false;
-  for (unsigned i = 0, e = Prefix.size(); i != e; ++i)
-    if (Prefix[i] != Longer[i])
-      return false;
-  return true;
+  return std::equal(Prefix.begin(), Prefix.end(), Longer.begin());
 }