[attribs.cc] ICE with 4x underscores

[Marek Polacek]

On Tue, Jan 30, 2024 at 12:25:24PM +0000, Jonathan Wakely via Gcc wrote:
> On Tue, 30 Jan 2024, 10:35 Amol Surati via Gcc, <gcc@gcc.gnu.org> wrote:
> 
> > Hello,
> >
> > If a std attribute name is squeezed between 4x underscores,
> >
> 
> Which is undefined behaviour, but shouldn't crash.
> 
> the compiler (both 13.2 [1] and trunk [2]) experiences an ICE.
> >
> 
> Bug reports belong in bugzilla, not on the mailing list please.
> 
> https://gcc.gnu.org/bugs/

I've created <https://gcc.gnu.org/PR113674>:
[[____attr____]] causes internal compiler error: in decl_attributes, at attribs.cc:776

which crashes with both cc1{,plus}.  The problem happens when the attribute
is both in std_attributes and c_common_gnu_attributes, it seems.

Marek