#5834: Allow both INLINE and INLINABLE for the same function -------------------------------------+------------------------------------- Reporter: rl | Owner: Type: feature request | Status: new Priority: normal | Milestone: 8.0.1 Component: Compiler | Version: 7.5 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Description changed by bgamari: Old description:

Sometimes you really want both. Here is a small example:

{{{ module T where

foo :: Num a => a -> a -> a foo x y = x+y+1 }}}

{{{ module U where

import T

appl :: (a -> b) -> a -> b {-# NOINLINE appl #-} appl f x = f x

bar :: Int -> Int -> Int bar x y = appl foo x y }}}

If I mark `foo` as `INLINE`, then GHC generates this code for `bar`:

{{{ bar1 :: Int -> Int -> Int bar1 = foo @ Int $fNumInt

bar :: Int -> Int -> Int bar = \ (x_aa0 :: Int) (y_aa1 :: Int) -> appl @ Int @ (Int -> Int) bar1 x_aa0 y_aa1 }}}

Whereas with `INLINABLE`, we get a nice specialisation but, of course, not guarantees with respect to inlining.

In general, it seems that requiring a function to inline when it is saturated and requiring it two specialise when it isn't are two different things and shouldn't be mutually exclusive.

New description: Sometimes you really want both. Here is a small example: {{{#!hs module T where foo :: Num a => a -> a -> a foo x y = x+y+1 }}} {{{#!hs module U where import T appl :: (a -> b) -> a -> b {-# NOINLINE appl #-} appl f x = f x bar :: Int -> Int -> Int bar x y = appl foo x y }}} If I mark `foo` as `INLINE`, then GHC generates this code for `bar`: {{{#!hs bar1 :: Int -> Int -> Int bar1 = foo @ Int $fNumInt bar :: Int -> Int -> Int bar = \ (x_aa0 :: Int) (y_aa1 :: Int) -> appl @ Int @ (Int -> Int) bar1 x_aa0 y_aa1 }}} Whereas with `INLINABLE`, we get a nice specialisation but, of course, not guarantees with respect to inlining. In general, it seems that requiring a function to inline when it is saturated and requiring it to specialise when it isn't are two different things and shouldn't be mutually exclusive. -- -- Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/5834#comment:7 GHC http://www.haskell.org/ghc/ The Glasgow Haskell Compiler