https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109230
--- Comment #18 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:07fc3491260e6b5d261433c977a4e069f5ab40c1 commit r13-6866-g07fc3491260e6b5d261433c977a4e069f5ab40c1 Author: Jakub Jelinek <ja...@redhat.com> Date: Sun Mar 26 20:17:00 2023 +0200 match.pd: Fix up fneg/fadd simplification [PR109230] The following testcase is miscompiled on aarch64-linux. match.pd has a simplification for addsub, where it negates one of the vectors in twice as large floating point element vector (effectively negating every other element) and then doing addition. But a requirement for that is that the permutation picks the right elements, in particular 0, nelts+1, 2, nelts+3, 4, nelts+5, ... The pattern tests this with sel.series_p (0, 2, 0, 2) check, which as documented verifies that the even elements of the permutation mask are identity, but doesn't say anything about the others. The following patch fixes it by also checking that the odd elements start at nelts + 1 with the same step of 2. 2023-03-26 Jakub Jelinek <ja...@redhat.com> PR tree-optimization/109230 * match.pd (fneg/fadd simplify): Verify also odd permutation indexes. * gcc.dg/pr109230.c: New test.
