Computing imp_finst can take up significant amount of time
I profiled a build of a production code base with thousands of modules and merging imp_finsts
[1] from different imports came up on top taking up 9% of total compile time.
I made a synthetic test case to reproduce the issue (see attached generateModules
).
The test case is basically multiple layers of modules where each module defines a type family instance through deriving Generic.
The problem is quite obvious, unionLists
is quadratic and imp_finsts
just keeps growing with the size of the code base.
Trac metadata
Trac field | Value |
---|---|
Version | |
Type | Bug |
TypeOfFailure | OtherFailure |
Priority | normal |
Resolution | Unresolved |
Component | Compiler (Type checker) |
Test case | |
Differential revisions | |
BlockedBy | |
Related | |
Blocking | |
CC | |
Operating system | |
Architecture |