[commit: packages/bytestring] master, revert-46-patch-1, wip/nix-local-build: Tiny performance tweak. (7fda8bd)

[git at git.haskell.org]

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

On branches: master,revert-46-patch-1,wip/nix-local-build
Link       : http://git.haskell.org/packages/bytestring.git/commitdiff/7fda8bd8f5e13a1dddbe8baf16ac5f96b2586125

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

commit 7fda8bd8f5e13a1dddbe8baf16ac5f96b2586125
Author: Sean <burton.seanr at gmail.com>
Date:   Mon Sep 28 16:10:51 2015 +0100

    Tiny performance tweak.


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

7fda8bd8f5e13a1dddbe8baf16ac5f96b2586125
 Data/ByteString.hs | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/Data/ByteString.hs b/Data/ByteString.hs
index 2737549..970693c 100644
--- a/Data/ByteString.hs
+++ b/Data/ByteString.hs
@@ -322,6 +322,7 @@ unsafeDupablePerformIO = unsafePerformIO
 #endif
 
 #if !MIN_VERSION_base(4,7,0)
+finiteBitSize :: Word -> Int
 finiteBitSize = bitSize
 #endif
 
@@ -1364,9 +1365,9 @@ breakSubstring pat =
         m           = k ^ lp
         get = fromIntegral . unsafeIndex src
         search !hs !i
-            | hp == hs && pat `isPrefixOf` b = u
-            | length src <= i                = (src,empty) -- not found
-            | otherwise                      = search hs' (i + 1)
+            | hp == hs && pat == unsafeTake lp b = u
+            | length src <= i                    = (src,empty) -- not found
+            | otherwise                          = search hs' (i + 1)
           where
             u@(_, b) = unsafeSplitAt (i - lp) src
             hs' = hs * k +