[Bug tree-optimization/96691] New: Failure to optimize not+or+xor with constants to and+xor with bitwise not-ed constants

[gabravier at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96691

            Bug ID: 96691
           Summary: Failure to optimize not+or+xor with constants to
                    and+xor with bitwise not-ed constants
           Product: gcc
           Version: 11.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gabravier at gmail dot com
  Target Milestone: ---

int f(int x)
{
    return (~x | 123) ^ 321;
}

This can be optimized to `return (x & ~123) ^ ~321;` (and the same
transformation can be applied with any constants replacing 123 and 321). This
transformation is done by LLVM, but not by GCC.