https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61447
--- Comment #4 from Rich Felker <bugdal at aerifal dot cx> --- Indeed, I can't reproduce that aspect of the problem now. My best guess is that I accidentally used "gcc" rather than "gcc-4.9" for the test without -std=c11. I'll post a follow-up comment if I do find such a problem again. Back to the issue of _Alignof(object) however, I'm not so sure that your interpretation of the standard is correct anymore. At the very least the standard is ambiguous. 6.3.2.1 Lvalues, arrays, and function designators, paragraph 2, reads: "Except when it is the operand of the sizeof operator, the _Alignof operator, the unary & operator, the ++ operator, the -- operator, or the left operand of the . operator or an assignment operator, an lvalue that does not have array type is converted to the value stored in the designated object (and is no longer an lvalue); this is called lvalue conversion." This text does not make sense if an expression cannot be the operand of _Alignof. It's very possible that this is just residual cruft that should have been removed, but it would be nice to get some clarification on whether, from the committee's standpoint, the error is the presence of the above text or the omission of text about how _Alignof handles an argument that's not a type.
