[Bug tree-optimization/126669] New: use_in_zero_equality has a special case for COND_EXPR but that is dead

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126669

            Bug ID: 126669
           Summary: use_in_zero_equality has a special case for COND_EXPR
                    but that is dead
           Product: gcc
           Version: 17.0
            Status: UNCONFIRMED
          Keywords: internal-improvement
          Severity: enhancement
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---

```
          if (code == COND_EXPR)
            {
              tree cond_expr = gimple_assign_rhs1 (use_stmt);
              if ((TREE_CODE (cond_expr) != EQ_EXPR
                   && (TREE_CODE (cond_expr) != NE_EXPR))
                  || !integer_zerop (TREE_OPERAND (cond_expr, 1)))
                {
                  if (exclusive)
                    return NULL;
                  continue;
                }
            }
```

This dead, as COND_EXPR is always just a simple SSA_NAME or a constant.