Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/CodeGen/LiveIntervalUnion.h b/linux-x64/clang/include/llvm/CodeGen/LiveIntervalUnion.h
index b922e54..9e2799b 100644
--- a/linux-x64/clang/include/llvm/CodeGen/LiveIntervalUnion.h
+++ b/linux-x64/clang/include/llvm/CodeGen/LiveIntervalUnion.h
@@ -154,7 +154,7 @@
         unsigned MaxInterferingRegs = std::numeric_limits<unsigned>::max());
 
     // Was this virtual register visited during collectInterferingVRegs?
-    bool isSeenInterference(LiveInterval *VReg) const;
+    bool isSeenInterference(LiveInterval *VirtReg) const;
 
     // Did collectInterferingVRegs collect all interferences?
     bool seenAllInterferences() const { return SeenAllInterferences; }