The JIT is still a bit of an experimental project, so don’t take the answers I will give here for granted as they can change before the release. I also don’t want to get in depth into the details, but the general idea is that the JIT itself will support all kinds of PyTorch operations, but will treat most of them as non-optimizable black-boxes. On the other hand the 20% of the ops that make up for 80% of the graphs will be well understood and those will be the ones that will be automatically specialized. The tracing mechanism is there to stay and will be developed.
Can you please provide us with a case that causes the constants to appear in backward? This sounds like a bug to me and should be fixed. NB if I recall correctly we’ve been handling this incorrectly for some time, but it should be ok in master.