Memory usage exploding for complex pattern matching

Victor Miraldo (UU) v.cacciarimiraldo at
Fri Mar 30 15:06:26 UTC 2018


>>>> I have just tried compiling my code with 8.4.2 and using
>>>> -fmax-pmcheck-iterations=0,
>>>> I gave GHC 12GB of ram and it still ran out (through `ulimit
>>>> -v$((1024*1024*12))`).
>>> Hmmm, I'm a bit confused. Why are our results so different? How
>>> precisely are you invoking GHC?
>> Here I meant my whole code, not just the repro. I could have been more clear.
>> Nevertheless, I'm calling it through stack:
> I'll admit that I am a bit lost; Minimal.hs compiles for me with a
> maximum residency of ~3.5 GBytes with both -O1 and the PM check enabled
> using GHC 8.4.1. Is this not the repro you are referring to?

I get the same behavior as you for Minimal.hs.

The "my code" above referred to the whole library that I'm developping.
In fact, the Minimal.hs file contains a distilled version of that library with
a template haskell splice that we are trying to use in one of our
fully fledged examples.

Do you want me to produce a larger "NotSoMinimal.hs" closer to the real thing?


More information about the ghc-devs mailing list