llvm dev - Sep 2010 - [LLVMdev] [LLVMDev] [Question] How do I get the number of machine registers.

Jacob, have you completed the topological sorting or the registers? It
seems I iterate through sub/alias-registers quite often, and I think a
performance gain might occur if the sub-registers were grouped better.

Thanks,
Jeff Kunkel

On Sep 29, 2010, at 8:11 AM, Jeff Kunkel wrote:
> Jacob, have you completed the topological sorting or the registers? It
> seems I iterate through sub/alias-registers quite often, and I think a
> performance gain might occur if the sub-registers were grouped better.
I abandoned the experiment because it didn't give a significant performance
gain.

Another problem is that aliases don't always form a nice tree, so sometimes
topological sorting is not possible.

The fast register allocator now avoids iterating over aliases by using a
working-set strategy instead.

/jakob

I am just going with a cache strategy where I just eager evaluate the
get alias function.

- Jeff

On Wed, Sep 29, 2010 at 12:17 PM, Jakob Stoklund Olesen <stoklund at
2pi.dk> wrote:
>
> On Sep 29, 2010, at 8:11 AM, Jeff Kunkel wrote:
>
>> Jacob, have you completed the topological sorting or the registers? It
>> seems I iterate through sub/alias-registers quite often, and I think a
>> performance gain might occur if the sub-registers were grouped better.
>
> I abandoned the experiment because it didn't give a significant
performance gain.
>
> Another problem is that aliases don't always form a nice tree, so
sometimes topological sorting is not possible.
>
> The fast register allocator now avoids iterating over aliases by using a
working-set strategy instead.
>
> /jakob
>
>