dph and new code generator don't play nicely with each other

I'm looking at the current failure of DPH with the new code generator, which is a bit different from what I've dealt with before. The bug appears to be in the compiled libraries code, and I can tickle it with the following minimized example:

    {-# LANGUAGE ParallelArrays #-}
    {-# OPTIONS -fvectorise #-}
    module PrimesVect where

    import Data.Array.Parallel.Prelude
    import qualified Prelude          
                            
    f :: PArray Bool        
    f = toPArrayP f'

    f' :: [:Bool:]
    f' = [: True | _ <- singletonP True, g emptyP:]

    g :: [:Bool:] -> Bool
    g ps = andP [: True | _ <- ps:]

and a runner:

    import qualified Data.Array.Parallel.PArray as P
    import PrimesVect

    main = print (P.toList f)

I expect to get [True], but instead I get:

    dph-primespj-fast: libraries/vector/Data/Vector/Generic.hs:369 (slice): invalid slice (0,1,0)
    dph-primespj-fast: thread blocked indefinitely in an MVar operation

Now, in the situation that the library code is broken, I'd usually try to inline all of the library code and then pare that down into something manageable. Unfortunately, DPH is pretty closely tied to the compiler, so I don't see an easy way to do that. So I'm not really sure how to go about debugging this.

Note that we can't work on this bug until #5065 (closed) is resolved, since these tests are currently failing for unrelated reasons.

Trac metadata

Trac field	Value
Version	7.0.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Data Parallel Haskell
Test case
Differential revisions
BlockedBy	#5065 (closed)
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