#1969: enormous compile times
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Reporter: duncan | Owner:
Type: task | Status: new
Priority: low | Milestone:
Component: Compiler | Version: 6.8.1
Severity: normal | Keywords:
Difficulty: Difficult (1 week) | Testcase:
Architecture: Multiple | Os: Multiple
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Some modules cause ghc to take a very very long time (and a lot of memory)
to compile, even without optimisations.
Here is an example of a module that takes almost forever to compile. The
{{{WASH/HTML/HTMLMonad98.hs}}} module from WASH-2.12 http://www.informatik
.uni-freiburg.de/~thiemann/haskell/WASH/
It is a 185k, 5,800 line module consisting almost entirely of data, class
and instance declarations.
It might be interesting to use this module as a test case to profile ghc's
front end to see if there are any obvious inefficiencies or unecessary
non-linear algorithms.
{{{WASH/HTML/HTMLPrelude.hs}}} is almost as bad. Between the two of them
they push the overall compile time for WASH to several minutes with -O0
and nearly half an hour with -O1. GHC's memory use while compiling WASH
also grows to over 300Mb with -O0 and over 600Mb with -O1 (on a 64bit
box).
All in all, WASH is an excellent stress test for GHC.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1969>
GHC <http://www.haskell.org/ghc/>
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