Switch assert(0/false) llvm_unreachable.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140367 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Sema/SemaAttr.cpp b/lib/Sema/SemaAttr.cpp
index 1c49892..cd03069 100644
--- a/lib/Sema/SemaAttr.cpp
+++ b/lib/Sema/SemaAttr.cpp
@@ -265,7 +265,7 @@
     break;
 
   default:
-    assert(0 && "Invalid #pragma pack kind.");
+    llvm_unreachable("Invalid #pragma pack kind.");
   }
 }