[Bug tree-optimization/103215] [12 regression] gcc generates unexpected warnings on libx11-1.7.2: error: array subscript -2 is outside array bounds of

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=103215

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Last reconfirmed|                            |2021-11-12
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, though I don't see anywhere in the IR &MEM <char> [(void
*)&name_and_type + -2B];
I do see:
type_9 = &MEM <char> [(void *)type_3 + -2B];

But type_3 cannot be &name_and_type there because of a check before hand.

This is definitely VRP/CCP related with maybe jump threading involved.