[Bug tree-optimization/124061] New: niter analysis doesn't handle enum or _BitInt iterators

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124061

            Bug ID: 124061
           Summary: niter analysis doesn't handle enum or _BitInt
                    iterators
           Product: gcc
           Version: 16.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
          Assignee: unassigned at gcc dot gnu.org
          Reporter: rguenth at gcc dot gnu.org
  Target Milestone: ---

bool
number_of_iterations_exit_assumptions (class loop *loop, edge exit,
                                       class tree_niter_desc *niter,
                                       gcond **at_stmt, bool every_iteration,
                                       basic_block *body)
{
...
  if (TREE_CODE (type) != INTEGER_TYPE
      && !POINTER_TYPE_P (type))
    return false;


enum testcase (C++):
```
enum a : unsigned {};

int f(a limit)
{
  a i;
  for(i = (a)0; i < limit; i = a(i + 1))
   ;
  return i;
}
```

_BitInt testcase (C):
```
int f(_BitInt(64) limit)
{
  _BitInt(64) i;
  for(i = 0; i < limit; i++)
   ;
  return i;
}