mozilla/rust — pull request #7202 by pcwalton (2013-06-17 16:52:17+00:00)
Title: rustc: map node ids through a table that ensures bitset indexes in dataflow are dense

I'm pretty sure this got adequately reviewed by a combination of @nikomatsakis and @graydon so I'm rubber stamping it because I really want this in (it makes it much less likely for me to swap, allowing me to get more work done).