dmd 2.029 release

[bearophile]

Don:
> I really don't understand the backend. It's quite cryptic. Key acronyms 
> are AE, CP and VBE. Then there's Bin, Bgen, Bkill, etc.
> AE *might* be Available Expression (but what does that mean?)
> CP might be Copy Propagation info
> I've found that VBE = "Very Busy Expression"! (what does that mean?)

I suggest to add comments to the DMD source code every time a small mystery is revealed, to rename the files once a much better name is found, to improve and refactor the code every time it a good thing to do it. Every time you put your hand in the code you can improve the code locally and leave it better then before (this is the Scout principle in programming).
Then such patches/changes can be slowly folded back into DMD and with time the sources will improve and will become more readable. Once they can be understood better, further changes become faster and simpler.

Bye,
bearophile