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

[Ken Dyck]

On Wednesday, December 02, 2009 7:09 PM, Chris Lattner wrote:
> 
> On Dec 2, 2009, at 12:32 PM, Ken Dyck wrote:
> 
> > Would there be any interest/opposition to extending the set 
> of simple 
> > integer types in MVT to include the missing multiples of 8 
> (up to 64 
> > bits)? That is: i24, i40, i48, i56?
> >
> > Adding the types to MVT (and ValueTypes.td) would allow LLVM to be 
> > targeted to architectures that have registers and 
> operations of these 
> > sizes (for example, a 24-bit DSP that I'd like to develop a 
> back end 
> > for has 24-, 48- and 56-bit native integer types). Back ends are 
> > currently limited to using power-of-2 types in their TableGen 
> > descriptions.
> 
> I'm fine with doing this, but please only add the MVT types 
> you actually need.  Don't bother adding i40 unless you 
> support i40.  If someone needs it in the future, we can add 
> it at that point.

Judging from a comment near the end of BlackfinRegisterInfo.td, it looks
like the Blackfin back end could make use i40. Would you still like it
left out?

-Ken