On Tue, May 30, 2017 at 12:27 PM, Richard Biener
<richard.guenther@gmail.com> wrote:
> On Thu, May 25, 2017 at 5:16 PM, Bin.Cheng <amker.cheng@gmail.com> wrote:
>> On Tue, May 23, 2017 at 5:23 PM, Bin Cheng <Bin.Cheng@arm.com> wrote:
>>> Hi,
>>> As commented in https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80815#c1,
>>> We can relax minimal segment length of DR_B for merging.  With this change,
>>> the new test can be improved to only one alias check.  Note the
>>> condition is still accurate after this patch, it won't introduce false
>>> alias.
>>> Bootstrap and test on x86_64 and AArch64, is it OK?
>> Updated patch wrto change of previous patch.
>>
>> Bootstrap and test on x86_64 and AArch64.
>
> Please omit unnecessary braces.  Ok with that change.
>
> Note that
>
>           if (tree_fits_uhwi_p (dr_b1->seg_len))
>             {
>               min_seg_len_b = dr_b1->seg_len;
>               if (tree_int_cst_sign_bit (dr_b1->seg_len))
>                 min_seg_len_b = wi::neg (min_seg_len_b);
>
> the tree_fits_uhwi_p check is somewhat bogus now that min_seg_len_b is
> a wide-int.
> It should probably be changed to TREE_CODE (dr_b1->seg_len) == INTEGER_CST
> which also means  that
>
>               min_seg_len_b = wi::abs (dr_b1->seg_len);
>
> should work.
Thanks for reviewing.  Here is updated patch.  Bootstrap and test on
x86_64.  Is it OK?

Thanks,
bin
>
> Richard.
>
>
>> Thanks,
>> bin
>>>
>>> 2017-05-22  Bin Cheng  <bin.cheng@arm.com>
>>>
>>>         * tree-data-ref.c (prune_runtime_alias_test_list): Relax minimal
>>>         segment length for dr_b.
>>>
>>> gcc/testsuite/ChangeLog
>>> 2017-05-22  Bin Cheng  <bin.cheng@arm.com>
>>>
>>>         * gcc.dg/vect/pr80815-3.c: New test.