[GHC] #8731: long compilation time for module with large data type and partial record selectors
GHC
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Sun Nov 16 20:39:45 UTC 2014
#8731: long compilation time for module with large data type and partial record
selectors
-------------------------------------+-------------------------------------
Reporter: carter | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 7.10.1
Component: Compiler | Version: 7.8.1-rc1
Resolution: | Keywords:
Operating System: | Architecture: Unknown/Multiple
Unknown/Multiple | Difficulty: Unknown
Type of failure: Compile- | Blocked By:
time performance bug | Related Tickets:
Test Case: |
Blocking: |
Differential Revisions: |
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Comment (by thomie):
Timing results for the example from comment:1.
||= GHC || -O1 || -O2 ||
||= 7.4.2 || 4.9s || 16s ||
||= 7.6.3 || 5.0s || 15s ||
||= 7.8.3 || 4.4s || 12s ||
||= 7.9.20141113 || 4.4s || 14s ||
Command: `time ghc -fforce-recomp -O<n> Constant.hs`
Compilation takes only about 1 second, with either `-O1` or `-O2`, when I
remove the `deriving (Eq, Ord, Read, Show)` clause from `data Constant`.
The resulting object file also reduces in size from 1mb to 100kb.
--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8731#comment:7>
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