<div dir="ltr"><div dir="ltr">I am in the middle of a refactor. I will file a ticket once I am done.<br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Mon, 6 Sept 2021 at 20:17, Simon Peyton Jones <<a href="mailto:simonpj@microsoft.com">simonpj@microsoft.com</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
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<p class="MsoNormal"><span>Harendra<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span>That comes as a surprise to me. Could you possibly make a repo case, and say what version of the compiler does, and does not, specialise the function?<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span>File it as a ticket … to me it looks like a bug.<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span>Thanks<u></u><u></u></span></p>
<p class="MsoNormal"><span><u></u> <u></u></span></p>
<p class="MsoNormal"><span>Simon<u></u><u></u></span></p>
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<p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> ghc-devs <<a href="mailto:ghc-devs-bounces@haskell.org" target="_blank">ghc-devs-bounces@haskell.org</a>>
<b>On Behalf Of </b>Harendra Kumar<br>
<b>Sent:</b> 06 September 2021 14:11<br>
<b>To:</b> <a href="mailto:ghc-devs@haskell.org" target="_blank">ghc-devs@haskell.org</a><br>
<b>Subject:</b> Question about specialization<u></u><u></u></span></p>
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Hi GHC devs,<u></u><u></u></p>
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<u></u> <u></u></p>
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I have a simple program using the streamly library, as follows, the whole code is in the same module:<u></u><u></u></p>
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{-# INLINE iterateState #-}<br>
{-# SPECIALIZE iterateState :: Int -> SerialT (StateT Int IO) Int #-}<br>
iterateState :: MonadState Int m => Int -> SerialT m Int<br>
iterateState n = do<br>
x <- get<br>
if x > n<br>
then do<br>
put (x - 1)<br>
iterateState n<br>
else return x<u></u><u></u></p>
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main :: IO ()<br>
main = do<br>
State.evalStateT (S.drain (iterateState 0)) 100000<u></u><u></u></p>
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Earlier the SPECIALIZE pragma was not required on iterateState, but after some refactoring in the library (the monad bind of SerialT changed a bit), this program now requires a SPECIALIZE on iterateState to trigger specialization, just INLINE also does not
help.<u></u><u></u></p>
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My question is whether this may be expected in some conditions or is this something which can be considered a bug in the compiler? I am also curious what specifically could have made the compiler not specialize this anymore, is it the size of the function or
some other threshold?<u></u><u></u></p>
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<u></u> <u></u></p>
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Thanks,<u></u><u></u></p>
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Harendra<u></u><u></u></p>
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