Summary:
This does a bunch of things at once (sorry):
- Refactor atom/term normalisation so that terms that are really just
atoms become atoms.
- Use this to not bother adding special cases in the functions exported
in the .mli: `and_less_than`, `and_equal_binop`, `prune_binop`, etc.
all had special cases to avoid introducing terms that could be atoms.
That's not great because the same smarts wasn't applied to terms that
would only become atom-like after some normalisation, and led to weird
and duplicated code. Now it's much cleaner: just add the most
straighforward fact and normalise!
- Fix a bug: adding a new equality `x = linear` should *not* be done
using `Normalizer.merge_var_linarith` as this is an internal function
that assumes that `x` is the right representative in `x - linear`.
Instead, for abitrary equations of that form, `solve_eq` should be used.
- When `normalize_linear_eqs` discovers new linear equalities, normalize
again. Add fuel there too to avoid spending too much time doing that.
It could be that we don't need/want fuel there but then we'd need to
think very hard about why there's no infinite recursion possible and
that seems harder.
Reviewed By: skcho
Differential Revision: D23241282
fbshipit-source-id: e5b8c4759