[Bug middle-end/93582] [10 Regression] -Warray-bounds gives error: array subscript 0 is outside array bounds of struct E[1]

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93582

--- Comment #25 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:8aba425f4ebc5e2c054776d3cdddf13f7c1918f8

commit r10-6614-g8aba425f4ebc5e2c054776d3cdddf13f7c1918f8
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Feb 13 10:04:11 2020 +0100

    sccvn: Handle bitfields in vn_reference_lookup_3 [PR93582]

    The following patch is first step towards fixing PR93582.
    vn_reference_lookup_3 right now punts on anything that isn't byte aligned,
    so to be able to lookup a constant bitfield store, one needs to use
    the exact same COMPONENT_REF, otherwise it isn't found.

    This patch lifts up that that restriction if the bits to be loaded are
    covered by a single store of a constant (keeps the restriction so far
    for the multiple store case, can tweak that incrementally, but I think
    for bisection etc. it is worth to do it one step at a time).

    2020-02-13  Jakub Jelinek  <jakub@redhat.com>

        PR tree-optimization/93582
        * fold-const.h (shift_bytes_in_array_left,
        shift_bytes_in_array_right): Declare.
        * fold-const.c (shift_bytes_in_array_left,
        shift_bytes_in_array_right): New function, moved from
        gimple-ssa-store-merging.c, no longer static.
        * gimple-ssa-store-merging.c (shift_bytes_in_array): Move
        to gimple-ssa-store-merging.c and rename to shift_bytes_in_array_left.
        (shift_bytes_in_array_right): Move to gimple-ssa-store-merging.c.
        (encode_tree_to_bitpos): Use shift_bytes_in_array_left instead of
        shift_bytes_in_array.
        (verify_shift_bytes_in_array): Rename to ...
        (verify_shift_bytes_in_array_left): ... this.  Use
        shift_bytes_in_array_left instead of shift_bytes_in_array.
        (store_merging_c_tests): Call verify_shift_bytes_in_array_left
        instead of verify_shift_bytes_in_array.
        * tree-ssa-sccvn.c (vn_reference_lookup_3): For native_encode_expr
        / native_interpret_expr where the store covers all needed bits,
        punt on PDP-endian, otherwise allow all involved offsets and sizes
        not to be byte-aligned.

        * gcc.dg/tree-ssa/pr93582-1.c: New test.
        * gcc.dg/tree-ssa/pr93582-2.c: New test.
        * gcc.dg/tree-ssa/pr93582-3.c: New test.