isSpace is too slow

[igloo]

In the thread starting  http://www.haskell.org/pipermail/glasgow-haskell-users/2007-May/012608.html Neil Mitchell compares the speed is isSpace to C's functions:

C's isspace: 0.375
C's iswspace: 0.400
Char.isSpace: 0.672

The thread contains some discussions of possible solutions.

[guest]

Improving isSpace is going to be difficult. I've done some Criterion benchmarking of the suggested optimizations, and for most of them, the benefit is modest. This may reflect improved optimization in GHC 6.10.2.

However, there is a small improvement in gspace' and gspace''' as compared to gspace, so that might be worth doing?

[guest]

the criterion module with the variant implementations gspace', gspace, gspace

[guest]

first benchmark attempt; subsequent issues and incompleteness addressed in later runs

[guest]

(As with  http://hackage.haskell.org/trac/ghc/ticket/2143, the Shakespeare data file is downloaded from  http://www.gutenberg.org/etext/100 )

[morabbin]

Worth redoing the experiment for 7.6.1?