# why
- not having a heuristic is an error but should not crash, just provide 0 configs
- some heuristics are cross device type
- cleaner to be explicit about being cross device type than having to
enumerate every possible device type
# what
- on registration, supply device_type=None (explicitly) to say this
heuristic is cross device
- test to guard the heuristics hierarchies
# testing
```
python3 -bb -m pytest test/inductor/test_template_heuristics_registry.py
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/161767
Approved by: https://github.com/PaulZhang12
