GHC formally discontinuing 32-bit Windows support?

Ben Gamari ben at
Thu Jul 16 03:14:12 UTC 2020

tl;dr. Unless someone speaks up, GHC will formally discontinue
       its (currently-broken) support for 32-bit Windows in 8.12.

Hi everyone,

As some have noticed, recent GHC releases' support for 32-bit Windows
support can be generously described as "unreliable". This has been due
to a combination of platform limitations, native toolchain bugs, and a
general lack of capacity within the GHC community focusing on Windows

I won't summarise the concrete issues here (see #17961, and #17700 for the
current state-of-play) but let it suffice to say that we are currently
stuck due to a bug in GNU binutils. However, I was recently informed
that Cygwin and msys have recently discontinued their support for 32-bit
Windows. While GHC uses a toolchain from the mingw32-w64 project, it
seems only a matter of time before 32-bit builds cease there as well
(see [1] for a summary of the relationships between these projects).

Furthermore, Microsoft itself has said that 32-bit Windows 10 releases
will cease later this year. All of this suggests to me that supporting
32-bit Windows in GHC will be, at best, an up-hill battle. Even worse,
it is a battle with little to gained: essentially all Intel-based Windows
systems today run on 64-bit-capable systems. I know of no compelling
reasons why users would opt to use 32-bit Windows in 2020.

Consequently, I suggest that we should formally discontinue 32-bit
Windows support in GHC 8.12. In my opinion, GHC's limited engineering
capacity on Windows is better spent elsewhere.

However, if there are compelling reasons why some users still rely on
32-bit Windows support (despite it being largely unusable for the last
two years), please do let me know. I have been consistently surprised by
the number of users who have noted the absence of 32-bit Windows builds;
I would love to know why they seem to be so popular.


- Ben

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