https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90693
--- Comment #15 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Andrew Pinski <pins...@gcc.gnu.org>: https://gcc.gnu.org/g:75a4143d69a842d691c14a477b0ba277d8708fc7 commit r15-3550-g75a4143d69a842d691c14a477b0ba277d8708fc7 Author: Andrew Pinski <quic_apin...@quicinc.com> Date: Thu Aug 29 12:10:44 2024 -0700 middle-end: also optimized `popcount(a) <= 1` [PR90693] This expands on optimizing `popcount(a) == 1` to also handle `popcount(a) <= 1`. `<= 1` can be expanded as `(a & -a) == 0` like what is done for `== 1` if we know that a was nonzero. We have to do the optimization in 2 places due to if we have an optab entry for popcount or not. Built and tested for aarch64-linux-gnu. PR middle-end/90693 gcc/ChangeLog: * internal-fn.cc (expand_POPCOUNT): Handle the second argument being `-1` for `<= 1`. * tree-ssa-math-opts.cc (match_single_bit_test): Handle LE/GT cases. (math_opts_dom_walker::after_dom_children): Call match_single_bit_test for LE_EXPR/GT_EXPR also. gcc/testsuite/ChangeLog: * gcc.target/aarch64/popcnt-le-1.c: New test. * gcc.target/aarch64/popcnt-le-2.c: New test. * gcc.target/aarch64/popcnt-le-3.c: New test. Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
