- -- If we're not doing iterative coalescing then just do a conservative
- -- coalescing stage at the front.
+ -- If we're not doing iterative coalescing then do an aggressive coalescing first time
+ -- around and then conservative coalescing for subsequent passes.
+ --
+ -- Aggressive coalescing is a quick way to get rid of many reg-reg moves. However, if
+ -- there is a lot of register pressure and we do it on every round then it can make the
+ -- graph less colorable and prevent the algorithm from converging in a sensible number
+ -- of cycles.
+ --