[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 #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Author: jakub
Date: Thu Oct 11 17:39:46 2018
New Revision: 265047

URL: https://gcc.gnu.org/viewcvs?rev=265047&root=gcc&view=rev
Log:
        Backported from mainline
        2018-09-12  Jakub Jelinek  <jakub@redhat.com>
                    Andreas Krebbel  <krebbel@linux.ibm.com>

        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:
    branches/gcc-8-branch/gcc/testsuite/gcc.c-torture/execute/pr86844.c
    branches/gcc-8-branch/gcc/testsuite/gcc.dg/store_merging_22.c
    branches/gcc-8-branch/gcc/testsuite/gcc.dg/store_merging_23.c
Modified:
    branches/gcc-8-branch/gcc/ChangeLog
    branches/gcc-8-branch/gcc/gimple-ssa-store-merging.c
    branches/gcc-8-branch/gcc/testsuite/ChangeLog