https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105253
Hongtao.liu <crazylht at gmail dot com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |crazylht at gmail dot com --- Comment #16 from Hongtao.liu <crazylht at gmail dot com> --- (In reply to Jakub Jelinek from comment #11) > This is a regression (as in we don't want such a call in that case for > performance reasons and in the past we didn't emit it). Yes, just note it regresses 531.deepsjeng_r by 2% for -O2 -march=x86-64 since below function. typedef unsigned long long BITBOARD; int PopCount (BITBOARD b) { int c = 0; while (b) { b &= b - 1; c++; } return c; } popcnt is supported by x86-64_v2.