Add a test case for BuildInputOutputAliases

[alanwaketan]

Summary:
This patch tries to add a test case for BuildInputOutputAliases and fixes the corresponding metric which reports a bogus value that's the total number of outputs.

Test Plan:
PJRT_DEVICE=CPU python test/test_input_output_aliases.py

[alanwaketan]

This is still a WIP as I'm puzzled on the way how we trigger BuildInputOutputAliases and then I still need to add it to run_tests.sh. @JackCaoG Can you provide more insights?

[JackCaoG]

@alanwaketan do you still plan to merge this pr?

[alanwaketan]

@alanwaketan do you still plan to merge this pr?

Can we talk more about this tomorrow? I have some questions.

[JackCaoG]

Let me actually play with your code a bit, the way that BuildInputOutputAliases is written is confusing, I might need to add some comment to it or I will forget how it works very quickly.

[alanwaketan]

Let me actually play with your code a bit, the way that BuildInputOutputAliases is written is confusing, I might need to add some comment to it or I will forget how it works very quickly.

Sounds good. Feel free to develop on the branch.

[JackCaoG]

Ah I know what's going on, by

t2 = t2 + 2

you created an intermediate tensor with new tensor ID and assign it back to t2, if you do

t2 += 2

the alias count incremented as expected

[JackCaoG]

Let me rebase and add some comments to the code

[alanwaketan]

Ah I know what's going on, by

t2 = t2 + 2

you created an intermediate tensor with new tensor ID and assign it back to t2, if you do

t2 += 2

the alias count incremented as expected

This is tricky. Thanks for the investigation!

[JackCaoG]

This is a bit weird, but I am going to approve my own change lol

[alanwaketan]

I guess we can land this now, and later I can add more test cases for views. Thanks for helping this, Jack.

[JackCaoG]

@alanwaketan yea I will merge this once all test passed.