[Bug tree-optimization/86844] [8/9 regression] wrong code caused by store merging pass

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86844

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Wed Sep 12 09:25:07 2018
New Revision: 264232

URL: https://gcc.gnu.org/viewcvs?rev=264232&root=gcc&view=rev
Log:
        PR tree-optimization/86844
        * gimple-ssa-store-merging.c
        (imm_store_chain_info::coalesce_immediate): For overlapping stores, if
        there are any overlapping stores in between them, make sure they are
        also coalesced or we give up completely.

        * gcc.c-torture/execute/pr86844.c: New test.
        * gcc.dg/store_merging_22.c: New test.
        * gcc.dg/store_merging_23.c: New test.

Added:
    trunk/gcc/testsuite/gcc.c-torture/execute/pr86844.c
    trunk/gcc/testsuite/gcc.dg/store_merging_22.c
    trunk/gcc/testsuite/gcc.dg/store_merging_23.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/gimple-ssa-store-merging.c
    trunk/gcc/testsuite/ChangeLog