I am the author of the cl3 library on Hackage. I have noticed a huge increase of compile time and memory use when testing 8.2.2 and 8.4.2. ghc-8.0.2 compiled in 4:17.33 using 3.5 GB. ghc-8.2.2 compiled in 26:40.15 using 32.8 GB. This is an increase of 6x in time and 9x in memory. This is not all bad, my nbody benchmark has improved about 35% between ghc-8.0.2 and ghc-8.4.2 so the increased compilation time and memory usage are producing much better runtime performance. I am interested if you could suggest some workarounds to help others compile on systems with less resources. I have 64GB memory in my system and would like to test out some -fno-* GHC Options. Could you point me in the right direction? The library is almost entirely pure functions. I am also interested in other options, like if there are ways to rewrite things to make it easier on the compiler or using NOINLINE on a trouble spot and how to find that trouble spot.