From f251bf5827aa565f7c21e1833832fa4a1150ef41 Mon Sep 17 00:00:00 2001
From: Simon Peyton Jones
Date: Mon, 24 Dec 2012 14:44:31 +0000
Subject: [PATCH] Make sum and product INLINABLE
This was causing the bad behaviour in Trac #7507,
because 'sum' wasn't getting specialised to Int64.
It also deals with Trac #4321, which had the same cause.
This has a big effect on some nofib programs too:
--------------------------------------------------------------------------------
Program Allocs Runtime Elapsed TotalMem
------------------------------------------------------------------------
bernouilli -2.6% -2.0% -2.0% +0.0%
fft2 -23.8% 0.09 0.09 -16.7%
fluid -4.4% 0.01 0.01 +0.0%
hidden -3.2% +2.1% +1.8% +0.0%
integrate -38.0% -47.7% -47.7% -1.0%
x2n1 -30.2% 0.01 0.01 -50.0%
------------------------------------------------------------------------
Min -38.0% -47.7% -47.7% -50.0%
Max +0.4% +11.2% +11.8% +6.9%
Geometric Mean -1.3% +0.2% +0.2% -0.8%
---
libraries/base/Data/List.hs | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/libraries/base/Data/List.hs b/libraries/base/Data/List.hs
index 9d09c0a475..efd0fd105e 100644
--- a/libraries/base/Data/List.hs
+++ b/libraries/base/Data/List.hs
@@ -1033,8 +1033,13 @@ foldl1' _ [] = errorEmptyList "foldl1'"
{-# SPECIALISE sum :: [Int] -> Int #-}
{-# SPECIALISE sum :: [Integer] -> Integer #-}
+{-# INLINABLE sum #-}
{-# SPECIALISE product :: [Int] -> Int #-}
{-# SPECIALISE product :: [Integer] -> Integer #-}
+{-# INLINABLE product #-}
+-- We make 'sum' and 'product' inlinable so that we get specialisations
+-- at other types. See, for example, Trac #7507.
+
-- | The 'sum' function computes the sum of a finite list of numbers.
sum :: (Num a) => [a] -> a
-- | The 'product' function computes the product of a finite list of numbers.
--
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