[GHC] #14962: "ghc: Out of memory" upon compiling combination of map/foldl/setBit

[GHC]

#14962: "ghc: Out of memory" upon compiling combination of map/foldl/setBit
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        Reporter:  martijnbastiaan   |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Description changed by martijnbastiaan:

Old description:

> The following code snippet:
>
> {{{#!hs
> module Test where
>
> import Data.Bits (setBit)
> import Data.List
>
> f :: Integer
> f = foldl setBit 0 toSet
>   where
>     toSet = [n | (n, _) <- zip [0..] [1]]
> }}}
>
> Fails to compile, yielding:
>
> {{{
> martijn at qbltop:~/code/scratch$ ghc Test.hs -O1
> [1 of 1] Compiling Test             ( Test.hs, Test.o )
> ghc: Out of memory
> }}}
>
> A few observations:
>
> - Compiling with no optimizations (-O0) works fine
> - I have not found a function other than setBit which triggers this
> behavior
> - Changing foldl to its strict brother foldl' does not help
> - Changing the type signature of "f" from "Integer" to "Int" causes the
> code to compile just fine
>
> I have been unable to reduce this example any further. I am using GHC
> 8.2.1.

New description:

 The following code snippet:

 {{{#!hs
 module Test where

 import Data.Bits (setBit)

 f :: Integer
 f = foldl setBit 0 toSet
   where
     toSet = [n | (n, _) <- zip [0..] [1]]
 }}}

 Fails to compile, yielding:

 {{{
 martijn at qbltop:~/code/scratch$ ghc Test.hs -O1
 [1 of 1] Compiling Test             ( Test.hs, Test.o )
 ghc: Out of memory
 }}}

 A few observations:

 - Compiling with no optimizations (-O0) works fine
 - I have not found a function other than setBit which triggers this
 behavior
 - Changing foldl to its strict brother foldl' does not help
 - Changing the type signature of "f" from "Integer" to "Int" causes the
 code to compile just fine
 - Changing [0..] to something silly like [0..2^1024] does not trigger the
 bug

 I have been unable to reduce this example any further. I am using GHC
 8.2.1.

--

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14962#comment:1>
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