https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92038
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Author: jakub Date: Fri Nov 8 10:53:50 2019 New Revision: 277963 URL: https://gcc.gnu.org/viewcvs?rev=277963&root=gcc&view=rev Log: PR target/92038 * gimple-ssa-store-merging.c (find_constituent_stores): For return value only, return non-NULL if there is a single non-clobber constituent store even if there are constituent clobbers and return one of clobber constituent stores if all constituent stores are clobbers. (split_group): Handle clobbers. (imm_store_chain_info::output_merged_store): When computing bzero_first, look after all clobbers at the start. Don't count clobber stmts in orig_num_stmts, except if the first orig store is a clobber covering the whole area and split_stores cover the whole area, consider equal number of stmts ok. Punt if split_stores contains only ->orig stores and their number plus number of original clobbers is equal to original number of stmts. For ->orig, look past clobbers in the constituent stores. (imm_store_chain_info::output_merged_stores): Don't remove clobber stmts. (rhs_valid_for_store_merging_p): Don't return false for clobber stmt rhs. (store_valid_for_store_merging_p): Allow clobber stmts. (verify_clear_bit_region_be): Fix up a thinko in function comment. * g++.dg/opt/store-merging-1.C: New test. * g++.dg/opt/store-merging-2.C: New test. * g++.dg/opt/store-merging-3.C: New test. Added: trunk/gcc/testsuite/g++.dg/opt/store-merging-1.C trunk/gcc/testsuite/g++.dg/opt/store-merging-2.C trunk/gcc/testsuite/g++.dg/opt/store-merging-3.C Modified: trunk/gcc/ChangeLog trunk/gcc/gimple-ssa-store-merging.c trunk/gcc/testsuite/ChangeLog
