Switch assert(0/false) llvm_unreachable.

llvm-svn: 140367
diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index 1943a74..e4633f9 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -850,7 +850,7 @@
   if (const VarDecl *VD = dyn_cast<VarDecl>(D))
     return EmitGlobalVarDefinition(VD);
   
-  assert(0 && "Invalid argument to EmitGlobalDefinition()");
+  llvm_unreachable("Invalid argument to EmitGlobalDefinition()");
 }
 
 /// GetOrCreateLLVMFunction - If the specified mangled name is not in the