Automatic Reference Counting.

Language-design credit goes to a lot of people, but I particularly want
to single out Blaine Garst and Patrick Beard for their contributions.

Compiler implementation credit goes to Argyrios, Doug, Fariborz, and myself,
in no particular order.

llvm-svn: 133103
diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index da37bd5..75e5661 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -570,6 +570,8 @@
     case CK_GetObjCProperty:
     case CK_ToVoid:
     case CK_Dynamic:
+    case CK_ObjCProduceObject:
+    case CK_ObjCConsumeObject:
       return 0;
 
     // These might need to be supported for constexpr.