Silence gcc warning.

llvm-svn: 186879
diff --git a/llvm/lib/Option/Option.cpp b/llvm/lib/Option/Option.cpp
index bed779a..5b418e8 100644
--- a/llvm/lib/Option/Option.cpp
+++ b/llvm/lib/Option/Option.cpp
@@ -24,7 +24,7 @@
 
   // Multi-level aliases are not supported. This just simplifies option
   // tracking, it is not an inherent limitation.
-  assert(!Info || !getAlias().isValid() || !getAlias().getAlias().isValid() &&
+  assert((!Info || !getAlias().isValid() || !getAlias().getAlias().isValid()) &&
          "Multi-level aliases are not supported.");
 }