Runtime performance regression in 8.4
varosi reports that the code for his project is slower in 8.4.1 than 8.2.2:
Yesterday I successfully compiled it with GHC 8.4.1-rc1. I got compiled it with 8.2.2 and 8.0.2 as well and ran tests for about a minute each on my Intel Core i7 machine on Windows 10 x64.
I got this results:
GHC 8.4.1-rc1 Average time: 61.87s
GHC 8.2.2 Average time: 60.09s
GHC 8.0.2 Average time: 67.07s
We should look into why.