http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55513
Jakub Jelinek <jakub at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |jason at gcc dot gnu.org --- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-28 15:15:11 UTC --- In cp_parser_constant_expression when we call cp_parser_assignment_expression on the initializer, it returns ((char *) __builtin_memcpy ((char *) &str, (const char *) "Hello", 6);, 5) As this is C++11, we call potential_rvalue_constant_expression which returns true (the call in the COMPOUND_EXPR is builtin, and all its arguments are pontential_rvalue_constant_expression arguments). I bet somewhere later on we see that it is const and ignore the TREE_SIDE_EFFECTS initializer.