[Patch,AVR]: Fix PR36467, PR49687 (better widening mul)

[Richard Henderson]

On 07/18/2011 11:05 AM, Georg-Johann Lay wrote:
> What's bad with pre-reload splits?
> The only weak point is in target-independent code because there
> is nothing like split1_completed and other missing information
> for better pass-awareness.

Nothing's wrong with pre-reload splits.

However, what you've done is try very hard to work around reload
doing the Right Thing with constant spilling, namely re-generate
the constant rather than spill and restore it.  I cannot believe
that's the right way to proceed.

>> Does anything break if we simply move pass_split_after_reload
>> earlier?  Right to the beginning of pass_postreload for instance.
>> Seems to me that every port would gain by optimizing the stuff
>> that comes out of the post-reload splitters.
> 
> I don't know the reason for that or if other machines rely on it.

And that is something we need to find out.


r~