#14974: 2-fold memory usage regression GHC 8.2.2 -> GHC 8.4.1 compiling `mmark` package -------------------------------------+------------------------------------- Reporter: hvr | Owner: davide Type: bug | Status: new Priority: high | Milestone: 8.8.1 Component: Compiler | Version: 8.4.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by davide): The 2 peaks of the terms_per_pass.png​ plot are the core size after 3 consecutive 3 passes (for both the GHC 8.2.2 and GHC 8.4.1 peak): SpecConstr, SpecConstr, Simplifier. Note there are no other SpecConstr passes. The core size between GHC 8.2.2 and GHC 8.4.1 track very closely until immediately before the SpecConstr pass. Perhaps a small change in core (before SpecConstr) is allowing for more specialization to happen, or SpecConstr is needlessly creating more core. -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14974#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler