https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92420
--- Comment #2 from rsandifo at gcc dot gnu.org <rsandifo at gcc dot gnu.org> --- Author: rsandifo Date: Mon Nov 11 19:43:52 2019 New Revision: 278064 URL: https://gcc.gnu.org/viewcvs?rev=278064&root=gcc&view=rev Log: Fix SLP downward group access classification (PR92420) This PR was caused by the SLP handling in get_group_load_store_type returning VMAT_CONTIGUOUS rather than VMAT_CONTIGUOUS_REVERSE for downward groups. A more elaborate fix would be to try to combine the reverse permutation into SLP_TREE_LOAD_PERMUTATION for loads, but that's really a follow-on optimisation and not backport material. It might also not necessarily be a win, if the target supports (say) reversing and odd/even swaps as independent permutes but doesn't recognise the combined form. 2019-11-11 Richard Sandiford <richard.sandif...@arm.com> gcc/ PR tree-optimization/92420 * tree-vect-stmts.c (get_negative_load_store_type): Move further up file. (get_group_load_store_type): Use it for reversed SLP accesses. gcc/testsuite/ * gcc.dg/vect/pr92420.c: New test. Added: trunk/gcc/testsuite/gcc.dg/vect/pr92420.c Modified: trunk/gcc/ChangeLog trunk/gcc/testsuite/ChangeLog trunk/gcc/tree-vect-stmts.c
