[ssaupdate] SSA form updating rewrite

[Daniel Berlin]

>>
>> This was done to avoid the phi result name being released as we redirect
>> an edge and then move phi nodes from one block to another (if you mark
>> them for rewrite, it won't release the name), as the comment says.
>>
>> I don't see anything i nwhat you've done that would change this being
>> necessary.
>
> I did not quite understand what it was supposed to do.  But I hope you
> agree that it is an ugly hack (the functions were never supposed to
> be used this way), so I would recommend you to fix this somehow in
> mainline.

Yes, i have plans to fix this in 4.1.
--Dan