Add a bitmask for NoBuiltin. This should *not* be used.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@175843 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/IR/Attributes.cpp b/lib/IR/Attributes.cpp
index 96b17c3..84d14b4 100644
--- a/lib/IR/Attributes.cpp
+++ b/lib/IR/Attributes.cpp
@@ -394,7 +394,8 @@
   case Attribute::StackProtectStrong: return 1ULL << 35;
   case Attribute::ThreadSafety:    return 1ULL << 36;
   case Attribute::UninitializedChecks: return 1ULL << 37;
-  }
+  case Attribute::NoBuiltin:       return 1ULL << 38;
+ }
 }
 
 //===----------------------------------------------------------------------===//