Here are the pretty printed STG in GHC syntax:
WORKING (DoubleRep): prints 3.14
x0 :: Any
[GblId] =
    "Value: MyConA %d %d\n"#;

x1 :: Any
[GblId] =
    "Value: MyConB %lf\n"#;

main :: Any
[GblId] =
    [] \u [void_0E]
        case MyConB [3.14##] of x100 {
          __DEFAULT ->
              case x100 of x101 {
                MyConA x200 x202 -> __pkg_ccall [x0 x200 x202];
                MyConB x203 -> __pkg_ccall [x1 x203];
              };
        };

WRONG (FloatRep) : prints 0.00 instead of 3.14
x0 :: Any
[GblId] =
    "Value: MyConA %d %d\n"#;

x1 :: Any
[GblId] =
    "Value: MyConB %f\n"#;

main :: Any
[GblId] =
    [] \u [void_0E]
        case MyConB [3.14#] of x100 {
          __DEFAULT ->
              case x100 of x101 {
                MyConA x200 x202 -> __pkg_ccall [x0 x200 x202];
                MyConB x203 -> __pkg_ccall [x1 x203];
              };
        };

Thanks,
Csaba

On Wed, Jan 22, 2020 at 4:21 PM Csaba Hruska <csaba.hruska@gmail.com> wrote:
Sorry, I should have noted that the gist has a description comment at the bottom.


On Wed, Jan 22, 2020 at 3:21 PM Ömer Sinan Ağacan <omeragacan@gmail.com> wrote:
What is the problem you're having? What do you mean by "run into problems"?
What's going wrong?

It'd be helpful if you could show us your program in STG syntax.

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

It should be valid, yes.

I'd also try with `-dstg-lint -dcmm-lint`.

Ömer

Csaba Hruska <csaba.hruska@gmail.com>, 22 Oca 2020 Çar, 14:56
tarihinde şunu yazdı:
>
> 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.
>
> https://gist.github.com/csabahruska/e9e143390c863f7b10b0298a7ae80ac1
>
> Working program (DoubleRep):
> https://gist.github.com/csabahruska/e9e143390c863f7b10b0298a7ae80ac1#file-stgsample-hs-L134-L198
>
> Wrong program (FloatRep):
> https://gist.github.com/csabahruska/e9e143390c863f7b10b0298a7ae80ac1#file-stgsample-hs-L64-L132
>
> Thanks,
> Csaba
>
>
> _______________________________________________
> ghc-devs mailing list
> ghc-devs@haskell.org
> http://mail.haskell.org/cgi-bin/mailman/listinfo/ghc-devs