[LLVMdev] Pluggable Register Coalescers

[Christopher Lamb]

On Jul 11, 2007, at 11:39 AM, David Greene wrote:

> On Wednesday 11 July 2007 12:41, Tanya M. Lattner wrote:
>
>> I think the coalescer should be flexible enough to be run  
>> independent of
>> the register allocator. For example, you may want to expose the  
>> copies
>> induced by transforming out of SSA to the scheduler. If the  
>> scheduler is
>> run before register allocation, then you would want the coalescing to
>> happen before as well.
>
> I agree that we want to allow for this possibility, but there are some
> coalescers that cannot run independent of the register allocator.
> So how do we handle both?  If I as a user ask for a regalloc-dependent
> coalescer, what should it do if someone tries to run it as an  
> independent
> pass?

Could it be possible for there to be a harness type interface that  
would allow coalescers that support both modes to be hooked into the  
pass registration, and those that depend on the allocator not be  
registered as passes?

--
Christopher Lamb



-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-dev/attachments/20070711/a431ebe3/attachment.html>