On Tue, 11 Aug 2020, Qing Zhao wrote: > Hi, Alexandre, > > CC’ing Richard for his comments on this. > > > > On Aug 10, 2020, at 9:39 PM, Alexandre Oliva <ol...@adacore.com> wrote: > >> I think that moving how to zeroing the registers part to each target > >> will be a better solution since each target has > >> Better idea on how to use the most efficient insns to do the work. > > > > It's certainly good to allow machine-specific optimized code sequences, > > but it would certainly be desirable to have a machine-independent > > fallback. It doesn't seem exceedingly hard to loop over the registers > > and emit a (set (reg:M N) (const_int 0)) for each one that is to be > > zeroed out. > > The current implementation already includes such machine-independent code, it > should be very easy to add this. > > Richard, what’s your opinion on this? > Do we need a machine-independent implementation to zeroing the registers for > the default when the target does not provide a optimized > Implementation?
Well, at least silently doing nothing when the option is used would be bad. So at least a diagnostic would be required. Note since the option is quite elaborate on what (sub-)set of regs is supposed to be cleared I'm not sure an implementation not involving any target hook is possible? Richard. > Thanks. > > Qing > > > > > > > -- Richard Biener <rguent...@suse.de> SUSE Software Solutions Germany GmbH, Maxfeldstrasse 5, 90409 Nuernberg, Germany; GF: Felix Imendörffer; HRB 36809 (AG Nuernberg)
