[LLVMdev] Register based vector insert/extract

Christopher Lamb christopher.lamb at gmail.com
Mon Apr 23 18:07:54 CDT 2007


Thanks for the detailed response.

On Apr 23, 2007, at 4:22 PM, Chris Lattner wrote:

> Right.  Evan is currently focusing on getting the late stages of  
> the code
> generator (e.g. livevars) to be able to understand arbitrary machine
> instrs in the face of physreg subregs.  This lays the groundwork for
> handling vreg subregs, but won't solve it directly.

Is the work Evan doing a prerequisite for supporting vreg subregs?
Is there a PR for the feature Evan is working on?

>> Is any of this kind of work planned? The addition of those
>> MRegisterInfo functions has me curious...
>
> This is on our mid-term plan, which means we'll probably tackle it  
> over
> the next year or so, but we don't have any concrete plans in the  
> immediate
> future.  If you are interested, this should be a pretty reasonable  
> project
> that will give you a chance to become more familiar with various  
> pieces of
> the early code generator. :)

I have other higher priority tasks right now, but I think we'll want  
to have this in sooner rather than later. If you have any pointers on  
a good starting point it'd be mighty helpful. If I can get a grasp on  
it I'll start incremental work in the background.

Probably the place to start would be opening a PR. Does "Support for  
vreg subregs" capture the essence of the enhancement?

--
Christopher Lamb




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