Christophe LYON <christophe.l...@foss.st.com> writes: > On 15/10/2021 17:08, Richard Sandiford wrote: >> Christophe Lyon via Gcc-patches <gcc-patches@gcc.gnu.org> writes: >>> This patch covers a few builtins where we do not use the <mode> >>> iterator and thus we cannot use <MVE_vpred>. >>> >>> For v2di instructions, we use the V8BI mode for predicates. >> Why V8BI though, when VPRED uses HI? > > > Hmm.. I used your suggestion: > > https://gcc.gnu.org/pipermail/gcc-patches/2021-October/581362.html > > Maybe I misinterpreted it?
Gah! Sorry, that was a typo for V2BI :-( >> Would it make sense to define a V2BI? Or doesn't that work? > > I didn't try, I'll have a look. wrt the architecture, I'm not sure what > this would mean? Hmm, yeah, I guess V2BI is wrong because every 4th bit matters. It would need to be V4BI instead. I guess if the number of predicate elements doesn't match the number of data elements, there's probably not much point using a dedicated predicate mode. So yeah, maybe keeping HImode is better after all. Sorry for the misdirection. Richard
