#5920: stack overflow in strict function depending on return type
---------------------------------+------------------------------------------
Reporter: ben0x539 | Owner:
Type: bug | Status: new
Priority: normal | Milestone: 7.6.1
Component: Compiler | Version: 7.4.1
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: Runtime crash
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: |
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Changes (by pcapriotti):
* difficulty: => Unknown
* milestone: => 7.6.1
Comment:
Thanks for the report.
This doesn't seem to be related to strictness, but rather the
boxing/unboxing of the `Int` result, which makes the function non-tail
recursive. Probably the same issue as #4301.
Here's the generated Core for the `goInt` function:
{{{
Rec {
Main.$wgoInt [Occ=LoopBreaker]
:: GHC.Integer.Type.Integer
-> GHC.Integer.Type.Integer -> GHC.Prim.Int#
[GblId, Arity=2, Str=DmdType SS]
Main.$wgoInt =
\ (w_s1Jb :: GHC.Integer.Type.Integer)
(w1_s1Jc :: GHC.Integer.Type.Integer) ->
let {
$wfail_s1Ji :: GHC.Types.Int
[LclId, Str=DmdType]
$wfail_s1Ji =
case GHC.Integer.Type.eqInteger w1_s1Jc lvl1_r1JJ of _ {
GHC.Types.False ->
case Main.$wgoInt
w_s1Jb (GHC.Integer.Type.plusInteger w1_s1Jc
Main.main3)
of ww_s1Jf { __DEFAULT ->
GHC.Types.I# ww_s1Jf
};
GHC.Types.True ->
case Main.$wgoInt
(GHC.Integer.Type.plusInteger w_s1Jb Main.main3)
Main.main3
of ww_s1Jf { __DEFAULT ->
GHC.Types.I# ww_s1Jf
}
} } in
case GHC.Integer.Type.eqInteger w_s1Jb lvl_r1JI of _ {
GHC.Types.False ->
case $wfail_s1Ji of _ { GHC.Types.I# ww1_s1Jf -> ww1_s1Jf };
GHC.Types.True ->
case GHC.Integer.Type.eqInteger w1_s1Jc lvl1_r1JJ of _ {
GHC.Types.False ->
case $wfail_s1Ji of _ { GHC.Types.I# ww1_s1Jf -> ww1_s1Jf };
GHC.Types.True -> 0
}
}
end Rec }
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5920#comment:1>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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