As a first step towards fixing PR9641, add a CK_DynamicToNull cast kind which

represents a dynamic cast where we know that the result is always null.

For example:

struct A {
  virtual ~A();
};
struct B final : A { };
struct C { };

bool f(B* b) {
  return dynamic_cast<C*>(b);
}

llvm-svn: 129256

1 files changed, 1 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CGExprConstant.cpp b/clang/lib/CodeGen/CGExprConstant.cpp
index 822a999b963..578a37f0fcf 100644
--- a/clang/lib/CodeGen/CGExprConstant.cpp
+++ b/clang/lib/CodeGen/CGExprConstant.cpp
@@ -552,6 +552,7 @@ public:
     case CK_GetObjCProperty:
     case CK_ToVoid:
     case CK_Dynamic:
+    case CK_DynamicToNull:
     case CK_ResolveUnknownAnyType:
       return 0;