Re: defunctionalization

So the idea here to make it possible to have a function that can be specialized at certain types, and explicitly inlined at specific use sites, but ghc otherwise will not inline it? Cool! one thought: might it be simpler to instead have something like EXPLICIT-INLINABLE, rather that requiring the juxtaposition of two pragmas which "seem" contradictory? On Thu, Jul 18, 2013 at 3:30 PM, Nicolas Frisby wrote:

This table outlines my plan for the compatibility of the pragmas.

Each cell is formatted as "x/y", where "x" answers "Is the original RHS in the interface file?" and "y" answers "Will GHC try to inline it?".

NOINLINE INLINABLE INLINE <none> no/no yes/yes yes/enthusiastically

NOINLINE error yes/no error INLINABLE - error error INLINE - - error

The proposed new "yes/no" option gives the GHC user more control. It prevents GHC from inlining a function while still supporting the ability to use the annotated function's RHS in another module, via SPECIALISE or the special "inline" function. Moreover, the presence of the RHS in the .hi file could be used by tools other than GHC like plugins or a super-compiler.

On Thu, Jul 18, 2013 at 4:20 AM, Simon Peyton-Jones

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wrote:

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It seems a little weird, but the internal data types can express it, so if you can make the front end do the right thing I’d be happy to take it. (Don’t forget the manual.)****

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SImon****

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*From:* ghc-devs [mailto:ghc-devs-bounces@haskell.org] *On Behalf Of *Nicolas Frisby *Sent:* 16 July 2013 21:29 *To:* ghc-devs@haskell.org *Subject:* Re: defunctionalization****

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Ah, I misread that TidyPgm function.It looks like if I build the CoreUnfolding, GHC will respect it. It's just rejecting the pragma combination in HsSyn.****

On Jul 16, 2013 3:22 PM, "Nicolas Frisby" wrote:

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I'd like to put a NOINLINE and an INLINABLE pragma on a binding.

(I'm sketching a defunctionalization pass. I'd like the 'apply` routine

RHS to make it into the interface file, but I do not want it to be inlined, since that'd undo the defunctionalization.)

...

In other words, I'd like a CoreUnfolding value with the uf_guidance =

UnfNever.

...

It seems TidyPgm.addExternal ignores such a core unfolding.

Would GHC consider a patch to make this work?

Thanks.****

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