https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104686
--- Comment #13 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Biener <rgue...@gcc.gnu.org>: https://gcc.gnu.org/g:a8250bbaeb2e8250c20db477fe67fd085214be7c commit r12-7401-ga8250bbaeb2e8250c20db477fe67fd085214be7c Author: Richard Biener <rguent...@suse.de> Date: Fri Feb 25 14:19:44 2022 +0100 rtl-optimization/104686 - speed up conflict iteration The following replaces /* Skip bits that are zero. */ for (; (word & 1) == 0; word >>= 1) bit_num++; idioms in ira-int.h in the attempt to speedup update_conflict_hard_regno_costs which we're bound on in PR104686. The trick is to use ctz_hwi here which should pay off even with dense bitmaps on architectures that have HW support for this. For the PR in question this speeds up compile-time from 31s to 24s for me. 2022-02-25 Richard Biener <rguent...@suse.de> PR rtl-optimization/104686 * ira-int.h (minmax_set_iter_cond): Use ctz_hwi to elide loop skipping bits that are zero. (ira_object_conflict_iter_cond): Likewise.
