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Re: [PATCH RFC] add generic expansion for MULT_HIGHPART_EXP


> > > So - how difficult is it to fix BRIG to not use MULT_HIGHPART_EXPR if
> > > not supported?

Richard, how should we proceed from here?  Do you like the solution in the
initial mail, or would you prefer something else?  FWIW I agree with Pekka,
no need to burden BRIG FE with expanding mul-highpart.

> > Pekka, can you comment? I think you have fallback paths for vector types
> > only at the moment?
> 
> I think it involves pretty much moving the code of your patch to the
> BRIG frontend.
> To me it'd look a bit wrong in terms of "division of responsibilities"
> as this is not really
> frontend-specific as far as I understand (even if BRIG/HSAIL happened
> to be the only language
> supporting them currently).
> 
> > Does BRIG have mult-highpart for 64-bit integers? On 32-bit targets we
> > won't be able to easily expand them (but on 64-bit targets it is fine).
> 
> Yes it does. 32b targets are not high priority for BRIG FE at this
> point, so I wouldn't
> worry about this as we assume HSA's "large" model is used, so this is likely not
> the only problem when trying to generate for 32b machines.
> 
> > For scalar types I think we should prefer to implement a generic expansion
> > rather than have the frontend query the backend. For vector types I am not
> > sure.
> 
> In my relatively gcc-uneducated humble opinion these both belong more
> naturally to a
> target-specific expansion or "legalization" pass, which tries to
> convert tree nodes to what the target
> can support.
> 
> BR,
> Pekka
> 


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