RFD, draft patch: IRA costs for reg_equiv_invariant regs

[Vladimir Makarov]

Jeff Law wrote:
> On 06/02/10 13:17, Vladimir Makarov wrote:
>> Bernd Schmidt wrote:
>>>
>>> On a not-quite-unrelated note, in the 2004 GCC summit proceedings you
>>> write that you had implemented rematerialization.  Do you still have 
>>> the
>>> patch?
>>>
>>>
>> Here some code I found.  It is very old I have no idea its state but 
>> it is enough to get an idea about rematerlization between RA and 
>> reload.  IMHO, that is where rematerialization should be implemented 
>> (reload is another place but it could make reload even more 
>> complicated).  We discussed it recently with Maxim and I am CCing him 
>> too.
> I would strongly discourage handling rematerialization in reload.  
> Ideally work on rematerialization would dovetail with my own to split 
> ranges.  ie, when an expression is rematerialized, do so into a new 
> pseudo/allocno which is then allocated by the existing ira allocation 
> callbacks.
>
Right.  It is really worth for Bernd and Maxim to look at your branch 
reload-v2.