Compile time regression with StrictData on GHC 8.10.2
Summary
Getting large compile times and memory consumption when using in StrictData
compared to GHC 8.8.3.
In the larger project the example comes from I can get beyond it with -fsimplifier-passes=1
but -fno-spec-constr
doesn't appear to have an effect as in other vaguely similar sounding issues.
Steps to reproduce
Attached file cabal and source code.
> time cabal v2-build -w ghc-8.10.2
...
real 0m37.562s
The issue is still present if I define f
(commented out code) in the Semigroup
definition explicitly rather than using coerce
but not as bad:
> time cabal v2-build -w ghc-8.10.2
...
real 0m10.887s
Expected behavior
> time cabal v2-build -w ghc-8.8.3
...
real 0m2.382s
Environment
- GHC version used: 8.10.2
Optional:
- Operating System: Linux
- System Architecture: x86_64