assert -> llvm_unreachable

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@85125 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index ea84829..10f7d84 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -949,7 +949,7 @@
       return CodeGenModule::GVA_StrongExternal;
       
     case TSK_ExplicitInstantiationDeclaration:
-      assert(false && "Variable should not be instantiated");
+      llvm::llvm_unreachable("Variable should not be instantiated");
       // Fall through to treat this like any other instantiation.
         
     case TSK_ImplicitInstantiation: