Emit an error when trying to form a pointer-to-member to a bitfield.

As a bonus, avoids a crash on the IRGen side due to accepting invalid code.

llvm-svn: 117842
diff --git a/clang/test/SemaCXX/ptrtomember.cpp b/clang/test/SemaCXX/ptrtomember.cpp
index fb774d8..e84e931 100644
--- a/clang/test/SemaCXX/ptrtomember.cpp
+++ b/clang/test/SemaCXX/ptrtomember.cpp
@@ -11,3 +11,8 @@
     return (s->*ps)(1); // expected-error {{called object type 'int' is not a function or function pointer}}
 }
 
+struct S2 {
+  int bitfield : 1;
+};
+
+int S2::*pf = &S2::bitfield; // expected-error {{address of bit-field requested}}