#5550: GHC infinite loop when compiling vector
---------------------------------+------------------------------------------
Reporter: simonpj | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.2.1
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: None/Unknown
---------------------------------+------------------------------------------
Bas reports: When benchmarking my new [https://github.com/basvandijk
/vector-bytestring vector-bytestring] package I discovered that building
the following program causes GHC to go into, what seems to be, an infinite
loop:
{{{
import Data.Vector (Vector)
import qualified Data.Vector.Generic as VG
main = print $ VG.foldl f z (VG.fromList [] :: Vector Int)
f = flip (:)
z = []
}}}
I build it with:
{{{
$ ghc --make vectorGHCloop.hs -O2
}}}
It compiles fine without the -O2 or if you specify `-fno-enable-rewrite-
rules`. So it's probably a loop in a rule somewhere.
Note that the program also builds fine when I change the 'f' and 'z' to:
{{{
f = (+)
z = 0
}}}
I use vector-0.9 and ghc-7.2.1.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5550>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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