[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 #40 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:fe19699ae2883b252d30f98481d32dabff00744b

commit r10-7035-gfe19699ae2883b252d30f98481d32dabff00744b
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Thu Mar 5 08:00:04 2020 +0100

    sccvn: Fix handling of POINTER_PLUS_EXPR in memset offset [PR93582]

    > > where POINTER_PLUS_EXPR last operand has sizetype type, thus unsigned,
    > > and in the testcase gimple_assign_rhs2 (def) is thus
0xf000000000000001ULL
    > > which multiplied by 8 doesn't fit into signed HWI.  If it would be
treated
    > > as signed offset instead, it would fit (-0xfffffffffffffffLL,
multiplied
    > > by 8 is -0x7ffffffffffffff8LL).  Unfortunately with the poly_int
obfuscation
    > > I'm not sure how to convert it from unsigned to signed poly_int.
    >
    > mem_ref_offset provides a boiler-plate for this:
    >
    > poly_offset_int::from (wi::to_poly_wide (TREE_OPERAND (t, 1)), SIGNED);

    Thanks, that seems to work.
    The test now works on both big-endian and little-endian.

    2020-03-05  Richard Biener  <rguenther@suse.de>
            Jakub Jelinek  <jakub@redhat.com>

        PR tree-optimization/93582
        * tree-ssa-sccvn.c (vn_reference_lookup_3): Treat POINTER_PLUS_EXPR
        last operand as signed when looking for memset offset.  Formatting
        fix.

        * gcc.dg/tree-ssa/pr93582-11.c: New test.

    Co-authored-by: Richard Biener <rguenther@suse.de>