[LLVMdev] Adding multiples-of-8 integer types to MVT

Duncan Sands baldrick at free.fr
Thu Dec 3 04:43:57 PST 2009

>> Instead of putting the burden on the back-ends to implement 
>> special lowering code, why not implement code in the 
>> legalizer that would automatically sign extend them to the 
>> next largest power of 2 integer if the specific integer types 
>> were not supported. This would then remove the need of the 
>> back-ends to implement anything as LLVM would just generate 
>> extend the values to i32/i64 silently.
> I agree. It would be ideal to limit the changes to the legalizer. I've
> been working on this in a private branch for a little while and so far I
> haven't figured out a way to make it work. I'm fairly new to LLVM,
> though, so there's a good chance my failure is due to a personal lack of
> understanding rather than some fundamental technical issue. I'll keep
> working on it.  

I also agree that the type legalizer is the place to take care of it.
This would be straightforward for someone who has experience with the
type legalizer - the problem is finding someone with some spare time!



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