Add exhaustive testing to ValueRanges, fix bugs (#94939)
Since I didn't want to deal with nondeterministic tests, I went the exhaustive testing route for a fixed list of constants to look at. The tests generate random ranges, propagate the range through the function, and then pick elements in the range and check that the result on the operation is in the resulting range. This caught bugs in log, sqrt and pow.
My resolution for pow was a little special, because I had trouble figuring out the correct semantics under all inputs domains. Instead, I picked two input domains (pow on two point ranges, and pow where exponent is known) and only implemented those. Everything else we give up. I think this is unlikely to affect perf.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/94939
Approved by: https://github.com/lezcano, https://github.com/eellison, https://github.com/nunoplopes
