[NNC] API to reorder multiple loops (#55568)
Summary:
Fixes https://github.com/pytorch/pytorch/issues/52690
This PR adds the following APIs:
```
static bool areLoopsPerfectlyNested(const std::vector<For*>& loops);
static std::vector<For*> reorder(
const std::vector<For*>& loops,
const std::vector<size_t>& permutation);
```
The first API checks if the given list of loops are perfectly nested. The second API reorders the given list of loops according to the permutation specified.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/55568
Reviewed By: albanD
Differential Revision: D27689734
Pulled By: navahgar
fbshipit-source-id: dc1bffdbee068c3f401188035772b41847cbc7c6
