scala/scala — pull request #1157 by odersky (2012-08-17 17:17:22+00:00)
Title: Compile speed optimizations

Here's the combined effort of Greg and myself this week to make the compiler faster. Overall we seem to be getting between 10 and 15%. We still need to do analysis to find out what optimizations were most beneficial.

Some optimizations are beneficial for cold compilers and compilers warming up (this is what we see in the Scala build for instance). In particular method splitting seems to help. Other optimizations seem to mostly help in stable state when the compiler is fully jitted. These are harder to predict and often not intuitive at all. For instance method specialization might actually slow down the speed because it makes callsites polymorphic.

Review by @paulp @gkossakowski