Hello,

I try to use GHC backend via STG. For that reason I build small STG program AST maually. So far the generated programs worked fine (compile/link/run).

However I run into problems when a lifted ADT has a FloatRep argument.

Interestingly it works for DoubleRep.

I'm using GHC 8.6.1 64 bit to generate the code for the constructed STG AST.

I wonder if I break an invariant or is this actually a bug?

Is it valid to use FloatRep argument in a boxed ADT on 64 bit?

I made a gist with the Haskell source and the generated Cmm code is also included.

Working program (DoubleRep):
https://gist.github.com/csabahruska/e9e143390c863f7b10b0298a7ae80ac1#file-stgsample-hs-L134-L198

Wrong program (FloatRep):

Thanks,

Csaba