[Bug] LSTM duplicates parameters for each step in the timeseries

[SebastianBoblest]

It seems that TVM duplicates parameters in LSTMs and GRUs for each step in the input series.
This behavior has occurred before in the past but was fixed.
Maybe this issue is related to the refactoring done in #12213 but I could not really locate the source of the error.
I use TVM on commit ecbe4ca

I attached a zip file containing

1. a toy lstm model that takes an input with two steps.
2. a sample script to generate C code for it with TVM
3. the generated code.

If you look into module_0.txt you can clearly see that identical parameters are in there twice.

@zhang-yi-chi @mbrookhart @AndrewZhaoLuo @vdkhoi @UlrikHjort @MichaelJKlaiber
lstm_bug.zip
r

[zhang-yi-chi]

This behavior seems to occur before #12213 refactoring. I tried your script on commit 359a642 (one commit before #12213 merged cfa5525) and still got identical parameters in module_0.txt.

[SebastianBoblest]

Ok, I will try to figure out the commit that caused this then, thanks for looking into it!