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

llvm-svn: 203220
diff --git a/llvm/lib/CodeGen/MachineSink.cpp b/llvm/lib/CodeGen/MachineSink.cpp
index df38dfc..0a74f11 100644
--- a/llvm/lib/CodeGen/MachineSink.cpp
+++ b/llvm/lib/CodeGen/MachineSink.cpp
@@ -60,9 +60,9 @@
       initializeMachineSinkingPass(*PassRegistry::getPassRegistry());
     }
 
-    virtual bool runOnMachineFunction(MachineFunction &MF);
+    bool runOnMachineFunction(MachineFunction &MF) override;
 
-    virtual void getAnalysisUsage(AnalysisUsage &AU) const {
+    void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.setPreservesCFG();
       MachineFunctionPass::getAnalysisUsage(AU);
       AU.addRequired<AliasAnalysis>();
@@ -72,7 +72,7 @@
       AU.addPreserved<MachineLoopInfo>();
     }
 
-    virtual void releaseMemory() {
+    void releaseMemory() override {
       CEBCandidates.clear();
     }