#14614: Compile time regression when compiling alex generated files -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: closed Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Resolution: invalid | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: None/Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #11380 | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Changes (by AndreasK): * status: new => closed * resolution: => invalid Old description:
Compile time increased slightly from 7.10.3 to 8.0.2 and significantly when going to 8.2.2
{{{ compiler=ghc-7.10.3
/c/test/happy-example $ time ghc Tokens.hs -fforce-recomp -fno-code [1 of 1] Compiling Tokens ( Tokens.hs, nothing )
real 0m0.243s
compiler=ghc-8.0.2
/c/test/happy-example $ time ghc Tokens.hs -fforce-recomp -fno-code [1 of 1] Compiling Tokens ( Tokens.hs, nothing )
real 0m0.286s
compiler=ghc-8.2.2
$ time ghc Tokens.hs -fforce-recomp -fno-code [1 of 1] Compiling Tokens ( Tokens.hs, nothing )
real 0m0.721s }}}
New description: This seems to be caused by the difference in package dbs resulting in a constant time difference. -- Comment: This takes 0.8 seconds to just typecheck and desugar on GHC-8.2.2: {{{ module Tokens where import GHC.Exts data AlexAddr = AlexA# Addr# }}} 8.0.2: {{{ $ time ghc T.hs -fforce-recomp -fno-code [1 of 1] Compiling Tokens ( T.hs, nothing ) real 0m0.354s user 0m0.000s sys 0m0.000s }}} 8.2.2: {{{ time ghc T.hs -fforce-recomp -fno-code [1 of 1] Compiling Tokens ( T.hs, nothing ) real 0m0.866s user 0m0.015s sys 0m0.000s }}} T -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/14614#comment:1 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler