https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87528
--- Comment #5 from Martin Jambor <jamborm at gcc dot gnu.org> ---
(In reply to Richard Biener from comment #3)
> Can you point me to the source for which we generate the popcount call(s)?
> It might be not final value replacement but instead code-generating a niter
> analysis result.
It turns out it is as simple as:
----------------------------------------
typedef unsigned long long BITBOARD;
int PopCount (BITBOARD b) {
int c = 0;
while (b) {
b &= b - 1;
c++;
}
return c;
}
----------------------------------------
with -O3. Trunk generates a call to __popcountdi2 when GCC 7 (or
trunk with -march=skylake) does not.
