[Bug tree-optimization/102844] [9/10/11/12 Regression] gcc-9.x miscompiles unsigned char expression in switch

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102844

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Target Milestone|---                         |9.5
   Last reconfirmed|                            |2021-10-19
            Summary|gcc-9.x miscompiles         |[9/10/11/12 Regression]
                   |unsigned char expression in |gcc-9.x miscompiles
                   |switch                      |unsigned char expression in
                   |                            |switch
     Ever confirmed|0                           |1

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
So the problem first shows up in .vrp2.
  nd.7_11 = _34(D);
  _12 = _33(D) + -128;
  _13 = (unsigned char) _12;

Before:
  <bb 13> [local count: 25265782]:
<L4>:
  nd.7_11 = _46;
  _12 = _46 + -128;
  _13 = (unsigned char) _12;
  dic = _13;

This happens during the insertation of the assert statements.
I don't think there has been any known issues like this before.