On Fri, 12 Nov 2021, Andre Simoes Dias Vieira wrote: > > On 12/11/2021 10:56, Richard Biener wrote: > > On Thu, 11 Nov 2021, Andre Vieira (lists) wrote: > > > >> Hi, > >> > >> This patch introduces two IFN's FTRUNC32 and FTRUNC64, the corresponding > >> optabs and mappings. It also creates a backend pattern to implement them > >> for > >> aarch64 and a match.pd pattern to idiom recognize these. > >> These IFN's (and optabs) represent a truncation towards zero, as if > >> performed > >> by first casting it to a signed integer of 32 or 64 bits and then back to > >> the > >> same floating point type/mode. > >> > >> The match.pd pattern choses to use these, when supported, regardless of > >> trapping math, since these new patterns mimic the original behavior of > >> truncating through an integer. > >> > >> I didn't think any of the existing IFN's represented these. I know it's a > >> bit > >> late in stage 1, but I thought this might be OK given it's only used by a > >> single target and should have very little impact on anything else. > >> > >> Bootstrapped on aarch64-none-linux. > >> > >> OK for trunk? > > On the RTL side ftrunc32/ftrunc64 would probably be better a conversion > > optab (with two modes), so not > > > > +OPTAB_D (ftrunc32_optab, "ftrunc$asi2") > > +OPTAB_D (ftrunc64_optab, "ftrunc$adi2") > > > > but > > > > OPTAB_CD (ftrunc_shrt_optab, "ftrunc$a$I$b2") > > > > or so? I know that gets somewhat awkward for the internal function, > > but IMHO we shouldn't tie our hands because of that? > I tried doing this originally, but indeed I couldn't find a way to correctly > tie the internal function to it. > > direct_optab_supported_p with multiple types expect those to be of the same > mode. I see convert_optab_supported_p does but I don't know how that is > used... > > Any ideas?
No "nice" ones. The "usual" way is to provide fake arguments that specify the type/mode. We could use an integer argument directly secifying the mode (then the IL would look host dependent - ugh), or specify a constant zero in the intended mode (less visibly obvious - but at least with -gimple dumping you'd see the type...). In any case if people think going with two optabs is OK then please consider using ftruncsi and ftruncdi instead of 32/64. Richard.
