https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94589
--- Comment #24 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Jakub Jelinek <ja...@gcc.gnu.org>: https://gcc.gnu.org/g:2b536797f7e43c55072a3215735f5833f1d6d218 commit r12-935-g2b536797f7e43c55072a3215735f5833f1d6d218 Author: Jakub Jelinek <ja...@redhat.com> Date: Thu May 20 09:10:38 2021 +0200 phiopt: Simplify (X & Y) == X -> (X & ~Y) == 0 even in presence of integral conversions [PR94589] On Wed, May 19, 2021 at 10:15:53AM +0200, Christophe Lyon via Gcc-patches wrote: > After this update, the test fails on arm and aarch64: according to the > logs, the optimization is still performed 14 times. Seems this is because if (change && !flag_syntax_only && (load_extend_op (TYPE_MODE (TREE_TYPE (and0))) == ZERO_EXTEND)) { tree uns = unsigned_type_for (TREE_TYPE (and0)); and0 = fold_convert_loc (loc, uns, and0); and1 = fold_convert_loc (loc, uns, and1); } in fold-const.c adds on these targets extra casts that prevent the optimizations. 2021-05-20 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/94589 * match.pd ((X & Y) == X -> (X & ~Y) == 0): Simplify even in presence of integral conversions.