Avoiding construction of dead dictionaries

[Simon Peyton Jones]

Hi Mike

Repro case is something like
* Here is a source or files
* Compile like this
* Look at the generated Core...observe silly thing happening

Evidence of importance could be as simple as "in my application I'm seeing a lot of these redundant dictionaries being built for no reason".  Or, stronger "this is slowing my application down by 5%".  TL;DR: is this just a curiosity that you noticed, or is it something that matters to you, and if so why?

|  Is there any way to see how far evaluates the dictionary construction to be
|  able to match on that unboxed tuple?

Not sure what you mean here, but once we have a repro case we can discuss.

Worth opening a ticket too -- email is easily lost.

Thanks

Simon

|  -----Original Message-----
|  From: Michael Sperber <sperber at deinprogramm.de>
|  Sent: 12 August 2021 10:15
|  To: Simon Peyton Jones <simonpj at microsoft.com>
|  Cc: Sebastian Graf <sgraf1337 at gmail.com>; glasgow-haskell-users at haskell.org
|  Subject: Re: Avoiding construction of dead dictionaries
|  
|  
|  On Mon, Aug 09 2021, Simon Peyton Jones <simonpj at microsoft.com> wrote:
|  
|  > Could you offer a small repro case, with a pointer to evidence that it
|  matters in practice, and open a ticket?
|  
|  I'll try my best, but I'm unsure how I would generate evidence.  Could you
|  give me a hint?
|  
|  Is there any way to see how far evaluates the dictionary construction to be
|  able to match on that unboxed tuple?
|  
|  --
|  Regards,
|  Mike