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Re: [PATCH, IRA] Fix ALLOCNO_MODE in the case of paradoxical subreg.

>  To define for what occurrence of the pseudo we should do the
> transformation, we need to create allocnos and calculate reg classes to
> know what paradoxical subreg needs more hard regs (the transformations
> can not be done for all paradoxical subregs as my experience shows many
> RTL changes result in worse RA even if we have heuristics to remove the
> generated changes as in this case would be trying to assign the same
> hard reg for the original and the new pseudo).
>   After doing the transformations, we need to recalculate reg classes
> and rebuild allocnos (both are expensive).  To speed up the process it
> could be implemented as some kind of update of already existing data but
> it will complicate code much.

I see, thanks!

> So right now I think implementing this in LRA would be easier  Still LRA
> has a pretty good register (re-)allocation (although it is worse than in
> IRA).

When you get an idea how to fix it in LRA, if you are still busy, I
would be happy to do the implementation if you could brief your idea.

Wei Mi.

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