[Bug tree-optimization/81884] [6 Regression] Invalid code generation with zero size arrays or flexible array members

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81884

--- Comment #13 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Thu Jun 21 07:24:06 2018
New Revision: 261833

URL: https://gcc.gnu.org/viewcvs?rev=261833&root=gcc&view=rev
Log:
2018-06-21  Richard Biener  <rguenther@suse.de>

        Backport from mainline
        2017-08-21  Richard Biener  <rguenther@suse.de>

        PR middle-end/81884
        * tree-ssa-alias.c (stmt_kills_ref_p): Handle array accesses
        at struct end conservatively when comparing common bases.

        * g++.dg/torture/pr81884.C: New testcase.

        2017-05-04  Richard Biener  <rguenther@suse.de>

        * tree.c (array_at_struct_end_p): Handle arrays at struct
        end with flexarrays more conservatively.  Refactor and treat
        arrays of arrays or aggregates more strict.  Fix
        VIEW_CONVERT_EXPR handling.

        2018-04-06  Richard Biener  <rguenther@suse.de>

        PR middle-end/85244
        * tree-dfa.c (get_ref_base_and_extent): Reset seen_variable_array_ref
        after seeing a component reference with an adjacent field.  Treat
        refs to arrays at struct end of external decls similar to
        refs to unconstrained commons.

        * gcc.dg/torture/pr85244-1.c: New testcase.
        * gcc.dg/torture/pr85244-2.c: Likewise.

        * gcc.dg/tree-prof/pr66295.c: Remove unsupported dg-error scanning.

Added:
    branches/gcc-6-branch/gcc/testsuite/g++.dg/torture/pr81884.C
    branches/gcc-6-branch/gcc/testsuite/gcc.dg/torture/pr85244-1.c
    branches/gcc-6-branch/gcc/testsuite/gcc.dg/torture/pr85244-2.c
Modified:
    branches/gcc-6-branch/gcc/ChangeLog
    branches/gcc-6-branch/gcc/testsuite/ChangeLog
    branches/gcc-6-branch/gcc/testsuite/gcc.dg/tree-prof/pr66295.c
    branches/gcc-6-branch/gcc/tree-dfa.c
    branches/gcc-6-branch/gcc/tree-ssa-alias.c
    branches/gcc-6-branch/gcc/tree.c