I showed this to you earlier, but just a note for the future. Compiling some simple example code (http://www.scala-lang.org/old/node/60.html): 

$ time scalac -optimise vectors.scala
real	0m5.577s
user	0m12.004s
sys	0m0.268s

$ time scalac  vectors.scala
real	0m4.084s
user	0m8.363s
sys	0m0.202s

$ time scalac   -Yskip:inliner,specialize,selectivecps,closelim,dce,selectiveanf vectors.scala
real	0m3.405s
user	0m6.878s
sys	0m0.166s