https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99544
--- Comment #6 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:bbdf59fdbc2ce41ccfac807b15cf3fac7b465a56 commit r11-7656-gbbdf59fdbc2ce41ccfac807b15cf3fac7b465a56 Author: Jakub Jelinek <ja...@redhat.com> Date: Sat Mar 13 08:56:15 2021 +0100 match.pd: Don't optimize vector X + (X << C) -> X * (1 + (1 << C)) if there is no mult support [PR99544] E.g. on aarch64, the target has V2DImode addition and shift by scalar optabs, but doesn't have V2DImode multiply. The following testcase ICEs because this simplification is done after last lowering, but generally, even if it is done before that, turning it into a multiplication will not be an improvement because that means scalarization, while the former can be done in vectors. It would be nice if we added expansion support for vector multiplication by uniform constants using shifts and additions like we have for scalar multiplication, but that is something that can be done in stage1. 2021-03-13 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/99544 * match.pd (X + (X << C) -> X * (1 + (1 << C))): Don't simplify if for vector types multiplication can't be done in type's mode. * gcc.dg/gomp/pr99544.c: New test.
