[commit: ghc] master: Allow enumDeltaIntegerFB to be inlined (78053f4)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : master
Link       : http://ghc.haskell.org/trac/ghc/changeset/78053f449d47a90c977ec3a893524f2cdb5d33f9/ghc

>---------------------------------------------------------------

commit 78053f449d47a90c977ec3a893524f2cdb5d33f9
Author: Joachim Breitner <mail at joachim-breitner.de>
Date:   Mon Sep 28 13:48:40 2015 +0200

    Allow enumDeltaIntegerFB to be inlined
    
    The function is very small and the compiler should be at liberty to
    inline it. But it is recursive, so it did not do it before. By applying
    the usual transformation with a local recursive function, GHC can now
    inline it, producing the loop that one would expect.


>---------------------------------------------------------------

78053f449d47a90c977ec3a893524f2cdb5d33f9
 libraries/base/GHC/Enum.hs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/libraries/base/GHC/Enum.hs b/libraries/base/GHC/Enum.hs
index a11d4f8..0d91cc7 100644
--- a/libraries/base/GHC/Enum.hs
+++ b/libraries/base/GHC/Enum.hs
@@ -704,7 +704,8 @@ the special case varies more from the general case, due to the issue of overflow
 
 {-# NOINLINE [0] enumDeltaIntegerFB #-}
 enumDeltaIntegerFB :: (Integer -> b -> b) -> Integer -> Integer -> b
-enumDeltaIntegerFB c x d = x `seq` (x `c` enumDeltaIntegerFB c (x+d) d)
+enumDeltaIntegerFB c x d = go x
+  where go x = x `seq` (x `c` go (x+d))
 
 {-# NOINLINE [1] enumDeltaInteger #-}
 enumDeltaInteger :: Integer -> Integer -> [Integer]