patch applied (ghc): Small optimisation for comparisons

[Simon Marlow]

Fri Jan 19 07:04:33 PST 2007  mrchebas at gmail.com
  * Small optimisation for comparisons
  Comparison of literal with narrowed/widened operand: perform
  the comparison at a different width, as long as the literal is
  within range.  We only do this on x86/x86_64 at the moment, where
  we have comparisons at different sizes available.

    M ./compiler/cmm/CmmOpt.hs +32