Re: FloatRep and DoubleRep ADT Argument in STG

Hello, I have to apologize because I've fooled myself. Everything works fine in the Haskell side. The problem was that I tried to pass a float value to printf which is a variadic C function. According to the C standard / stack overflow:

* because printf and its friends are variadic functions, so a float parameter undergoes automatic conversion to double as part of the default argument promotions (see section 6.5.2.2 of the C99 standard).*

Sorry for the confusion. Thanks, Csaba On Wed, Jan 22, 2020 at 10:27 PM Csaba Hruska wrote:

I added Stg and Cmm linter to my custom pipeline and they report no errors.

On Wed, Jan 22, 2020 at 4:40 PM Csaba Hruska wrote:

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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 wrote:

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Sorry, I should have noted that the gist has a description comment at the bottom.

https://gist.github.com/csabahruska/e9e143390c863f7b10b0298a7ae80ac1#gistcom...

On Wed, Jan 22, 2020 at 3:21 PM Ömer Sinan Ağacan wrote:

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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.

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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 , 22 Oca 2020 Çar, 14:56 tarihinde şunu yazdı:

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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-st...

...

Wrong program (FloatRep):

https://gist.github.com/csabahruska/e9e143390c863f7b10b0298a7ae80ac1#file-st...

...

Thanks, Csaba

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