Fix typos of occurred and occurrence

llvm-svn: 323316
diff --git a/clang/lib/Analysis/CloneDetection.cpp b/clang/lib/Analysis/CloneDetection.cpp
index 098803f..3c64f14 100644
--- a/clang/lib/Analysis/CloneDetection.cpp
+++ b/clang/lib/Analysis/CloneDetection.cpp
@@ -534,14 +534,14 @@
   // First check if we already reference this variable
   for (size_t KindIndex = 0; KindIndex < Variables.size(); ++KindIndex) {
     if (Variables[KindIndex] == VarDecl) {
-      // If yes, add a new occurence that points to the existing entry in
+      // If yes, add a new occurrence that points to the existing entry in
       // the Variables vector.
       Occurences.emplace_back(KindIndex, Mention);
       return;
     }
   }
   // If this variable wasn't already referenced, add it to the list of
-  // referenced variables and add a occurence that points to this new entry.
+  // referenced variables and add a occurrence that points to this new entry.
   Occurences.emplace_back(Variables.size(), Mention);
   Variables.push_back(VarDecl);
 }