[Bug tree-optimization/85244] [6/7/8 Regression] Bad optimisation with flexible array member (may be related to -ftree-dominator-opts)

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85244

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
Author: rguenth
Date: Fri Apr  6 11:47:18 2018
New Revision: 259168

URL: https://gcc.gnu.org/viewcvs?rev=259168&root=gcc&view=rev
Log:
2018-04-06  Richard Biener  <rguent...@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.

Added:
    trunk/gcc/testsuite/gcc.dg/torture/pr85244-1.c
    trunk/gcc/testsuite/gcc.dg/torture/pr85244-2.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/tree-dfa.c