[Bug c++/96184] [9/10 Regression] GCC treats "use of local variable with automatic storage from containing function" differently in versions

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96184

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
           Keywords|                            |rejects-valid
     Ever confirmed|0                           |1
            Summary|GCC treats "use of local    |[9/10 Regression] GCC
                   |variable with automatic     |treats "use of local
                   |storage from containing     |variable with automatic
                   |function" differently in    |storage from containing
                   |versions                    |function" differently in
                   |                            |versions
   Target Milestone|---                         |9.5
   Last reconfirmed|                            |2021-09-10

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So I think it is legal because if we have:


int main(){
    int a  = 10;
    int const b = 10;
    static constexpr int d = b ? 0 : a = b;
    auto p1 = [ ] () noexcept ( d) { return d;};
    return d;
}

the d is a constexpr at this point and a valid one and was even accepted before
in GCC 8.5.0.

So this is only a regression in GCC 9 and GCC 10.