On Mon, 28 Aug 2017, Jon Beniston wrote: > Hi Richard, > > >- if (nunits < 1) /* Support V1SI. */ > >+ if (nunits < 1 || (nunits == 1 && !reduct_p)) > > return NULL_TREE; > > > >doesn't seem to be against trunk which has > > > > if (nunits <= 1) > > return NULL_TREE; > > > >so what happens if you just change that to > > > > if (nunits < 1) > > return NULL_TREE; > > Ah, that's what I first tried, and mistakenly sent the patch against that. > > That did help the initial problem, but then I needed to add a lot of support > for the V1SI type in the backend (which just duplicated SI patterns) and > there are a few places where GCC seems to have sanity checks against vectors > that are only one element wide. A dot product producing a scalar result > seems natural.
Where do you need V1SI types? The vectorizer should perform a SI extract from V1SI here. You need to elaborate a bit here. > > Also, as well as ARC benefitting from this, I think the TI c6x port would > too. That currently has a sdot_prodv2hi pattern that uses SI and V2HI types. The vectorizer doesn't really support vector->scalar ops so V1SI feels more natural here. That is, your patch looks a bit ugly -- there's nothing wrong with V1SI vector types. So maybe instead of adjusting that function the respective caller when facing a lane-reducing op such as DOT_PROD needs to consider scalar result types. Richard. > Cheers, > Jon > > > -- Richard Biener <rguent...@suse.de> SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
