[commit: containers] master: On 32-bit architectures, improve highestBitMask. (dbc5fb6)

[Paolo Capriotti]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/containers

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/dbc5fb6be82398e391f40f31bbea81b859ceda9a

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

commit dbc5fb6be82398e391f40f31bbea81b859ceda9a
Author: Milan Straka <fox at ucw.cz>
Date:   Tue Apr 24 16:20:29 2012 +0200

    On 32-bit architectures, improve highestBitMask.
    
    Even on 32-bit architectures, bit shift of size 32 was performed.

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

 Data/IntMap/Base.hs |    7 +++++++
 Data/IntSet.hs      |   11 +++++++----
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/Data/IntMap/Base.hs b/Data/IntMap/Base.hs
index c10a5b3..b733475 100644
--- a/Data/IntMap/Base.hs
+++ b/Data/IntMap/Base.hs
@@ -227,6 +227,11 @@ import GHC.Exts ( Word(..), Int(..), shiftRL#, build )
 import Data.Word
 #endif
 
+-- On GHC, include MachDeps.h to get WORD_SIZE_IN_BITS macro.
+#if defined(__GLASGOW_HASKELL__)
+#include "MachDeps.h"
+#endif
+
 -- Use macros to define strictness of functions.
 -- STRICT_x_OF_y denotes an y-ary function strict in the x-th parameter.
 -- We do not use BangPatterns, because they are not in any standard and we
@@ -1943,7 +1948,9 @@ highestBitMask x0
       x2 -> case (x2 .|. shiftRL x2 4) of
        x3 -> case (x3 .|. shiftRL x3 8) of
         x4 -> case (x4 .|. shiftRL x4 16) of
+#if !(defined(__GLASGOW_HASKELL__) && WORD_SIZE_IN_BITS==32)
          x5 -> case (x5 .|. shiftRL x5 32) of   -- for 64 bit platforms
+#endif
           x6 -> (x6 `xor` (shiftRL x6 1))
 {-# INLINE highestBitMask #-}
 
diff --git a/Data/IntSet.hs b/Data/IntSet.hs
index 1316a39..ec0162e 100644
--- a/Data/IntSet.hs
+++ b/Data/IntSet.hs
@@ -182,6 +182,11 @@ import GHC.Prim ( uncheckedShiftL#, uncheckedShiftRL#, indexInt8OffAddr# )
 import Data.Word
 #endif
 
+-- On GHC, include MachDeps.h to get WORD_SIZE_IN_BITS macro.
+#if defined(__GLASGOW_HASKELL__)
+#include "MachDeps.h"
+#endif
+
 -- Use macros to define strictness of functions.
 -- STRICT_x_OF_y denotes an y-ary function strict in the x-th parameter.
 -- We do not use BangPatterns, because they are not in any standard and we
@@ -1188,7 +1193,9 @@ highestBitMask x0
       x2 -> case (x2 .|. shiftRL x2 4) of
        x3 -> case (x3 .|. shiftRL x3 8) of
         x4 -> case (x4 .|. shiftRL x4 16) of
+#if !(defined(__GLASGOW_HASKELL__) && WORD_SIZE_IN_BITS==32)
          x5 -> case (x5 .|. shiftRL x5 32) of   -- for 64 bit platforms
+#endif
           x6 -> (x6 `xor` (shiftRL x6 1))
 {-# INLINE highestBitMask #-}
 
@@ -1217,10 +1224,6 @@ foldr'Bits :: Int -> (Int -> a -> a) -> a -> Nat -> a
 {-# INLINE foldrBits #-}
 {-# INLINE foldr'Bits #-}
 
-#if defined(__GLASGOW_HASKELL__)
-#include "MachDeps.h"
-#endif
-
 #if defined(__GLASGOW_HASKELL__) && (WORD_SIZE_IN_BITS==32 || WORD_SIZE_IN_BITS==64)
 {----------------------------------------------------------------------
   For lowestBitSet we use wordsize-dependant implementation based on