[Bug tree-optimization/95961] ICE: in exact_div, at poly-int.h:2182

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95961

--- Comment #1 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Richard Sandiford <rsandifo@gcc.gnu.org>:

https://gcc.gnu.org/g:5c9669a0e6cbf477a03024522943197bdb2682d4

commit r11-1781-g5c9669a0e6cbf477a03024522943197bdb2682d4
Author: Fei Yang <felix.yang@huawei.com>
Date:   Thu Jul 2 10:14:33 2020 +0100

    vect: Fix an ICE in exact_div [PR95961]

    In the test case for PR95961, vectorization factor computed
    by vect_determine_vectorization_factor is [8,8].  But this is
    updated to [1,1] later by vect_update_vf_for_slp.  When we call
    vect_get_num_vectors in vect_enhance_data_refs_alignment, the number
    of scalars which is based on the vectorization factor is not a multiple
    of the the number of elements in the vector type.  This leads to
    the ICE.  This isn't a simple stream of contiguous vector accesses.
    It's hard to predict from the available information how many vector
    accesses we'll actually need per iteration.  As discussed, here we
    should use the number of scalars instead of the number of vectors as
    an upper bound for the loop saving info about DR in the hash table.

    2020-07-02  Felix Yang  <felix.yang@huawei.com>

    gcc/
            PR tree-optimization/95961
            * tree-vect-data-refs.c (vect_enhance_data_refs_alignment): Use the
            number of scalars instead of the number of vectors as an upper
bound
            for the loop saving info about DR in the hash table.  Remove unused
            local variables.

    gcc/testsuite/
            PR tree-optimization/95961
            * gcc.target/aarch64/sve/pr95961.c: New test.