[C++11] Add 'override' keyword to virtual methods that override their base class.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203220 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/Spiller.cpp

@@ -164,7 +164,7 @@ public:
                  VirtRegMap &vrm)
     : SpillerBase(pass, mf, vrm) {}
 
-  void spill(LiveRangeEdit &LRE) {
+  void spill(LiveRangeEdit &LRE) override {
     // Ignore spillIs - we don't use it.
     trivialSpillEverywhere(LRE);
   }