https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86677
--- Comment #11 from Martin Liška <marxin at gcc dot gnu.org> ---
(In reply to Wilco from comment #10)
> (In reply to Martin Liška from comment #9)
> > Taking look at
> > ../drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c file:
> >
> > The __builtin_popcount is generated from:
> >
> > static int brcmf_setup_wiphybands(struct brcmf_cfg80211_info *cfg)
> > {
> > ...
> > } else {
> > for (nchain = 0; rxchain; nchain++)
> > rxchain = rxchain & (rxchain - 1);
> > }
> > ...
> > }
> >
> > It started from r262486. I would that in this situation it's maybe
> > unexpected that a popcount call will be eventually generated. So I'm for an
> > option what will disable the pattern recognition.
>
> I'd say this is exactly a case where using a faster popcount instruction
> helps - if available of course.
Yes, but as seen in PR87528, using a libgcc can slow down a SPEC benchmark. But
it's related to generic tuning.
>
> Is there any reason -fno-builtin-popcount can't also block automatic
> generation of popcount?
Do we really have such option?
