`isclose` gives false positives for large integers.

[pmeier]

🐛 Bug

isclose gives false positives for large integers.

To Reproduce

>>> a = torch.tensor(140499600015872)
>>> b = torch.tensor(140499600015360)
>>> a == b
tensor(False)
>>> abs(a - b) <= 0
tensor(False)
>>> torch.isclose(a, b, atol=0, rtol=0)
tensor(True)

Expected behavior

a and b should not be considered close.

cc @ezyang @gchanan @zou3519 @bdhirsh @jbschlosser @anjali411

[mruberry]

Great catch, @pmeier. We would accept a fix for this. I think the current algorithm can bias towards correctness over performance more with a little extra casting logic and possibly an atol=rtol=0 special case.

Note this issue is limited to integer values not representable as fp32 values.