Use an emplace_back for consistency, NFC

llvm-svn: 269199
diff --git a/llvm/lib/ProfileData/InstrProf.cpp b/llvm/lib/ProfileData/InstrProf.cpp
index f459d2d..b6cc077 100644
--- a/llvm/lib/ProfileData/InstrProf.cpp
+++ b/llvm/lib/ProfileData/InstrProf.cpp
@@ -428,7 +428,7 @@
   std::vector<InstrProfValueSiteRecord> &ValueSites =
       getValueSitesForKind(ValueKind);
   if (N == 0)
-    ValueSites.push_back(InstrProfValueSiteRecord());
+    ValueSites.emplace_back();
   else
     ValueSites.emplace_back(VData, VData + N);
 }