Update clang to r339409.

Change-Id: I800772d2d838223be1f6b40d490c4591b937fca2
diff --git a/linux-x64/clang/include/llvm/Support/KnownBits.h b/linux-x64/clang/include/llvm/Support/KnownBits.h
index 97e73b1..259df95 100644
--- a/linux-x64/clang/include/llvm/Support/KnownBits.h
+++ b/linux-x64/clang/include/llvm/Support/KnownBits.h
@@ -103,7 +103,7 @@
     One.setSignBit();
   }
 
-  /// Make this value negative.
+  /// Make this value non-negative.
   void makeNonNegative() {
     Zero.setSignBit();
   }