[Bug tree-optimization/120944] [12/13/14/15/16 Regression] Incorrect optimization with accessing a volatile structure member

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120944

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |10.1.0
   Last reconfirmed|                            |2025-07-03
      Known to work|                            |9.1.0, 9.5.0
           Keywords|                            |wrong-code
     Ever confirmed|0                           |1
            Summary|Incorrect optimization with |[12/13/14/15/16 Regression]
                   |accessing a volatile        |Incorrect optimization with
                   |structure member            |accessing a volatile
                   |                            |structure member
             Status|UNCONFIRMED                 |NEW
   Target Milestone|---                         |12.5

--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Confirmed, fre looks to prop through volatile accesses:

Processing block 0: BB2
Value numbering stmt = d_3(D)->D.3475.a.u32 ={v} -1;
Setting value number of .MEM_4 to .MEM_4 (changed)
Value numbering stmt = u ={v} d_3(D)->D.3475.a;
Setting value number of .MEM_5 to .MEM_5 (changed)
Value numbering stmt = _1 = u.D.3467.A;
Setting value number of _1 to -1 (changed)

Started in GCC 10.