On Thu, Nov 5, 2015 at 2:22 PM, Alan Lawrence <alan.lawre...@arm.com> wrote:
> On 30/10/15 10:54, Eric Botcazou wrote:
>> On 30/10/15 10:44, Richard Biener wrote:
>>>
>>> I think you want to use wide-ints here and
>>>
>>> wide_int idx = wi::from (minidx, TYPE_PRECISION (TYPE_DOMAIN
>>> (...)), TYPE_SIGN (TYPE_DOMAIN (..)));
>>> wide_int maxidx = ...
>>>
>>> you can then simply iterate minidx with ++ and do the final compare
>>> against maxidx
>>> with while (++idx <= maxidx). For the array ref index we want to use
>>> TYPE_DOMAIN
>>> as type as well, not size_int. Thus wide_int_to_tree (TYPE_DOMAIN
>>> (...)..idx).
> [...]
>> But using offset_int should be OK, see for example get_ref_base_and_extent.
>>
>
> Here's a patch using offset_int. (Not as easy to construct as wide_int::from,
> the sign-extend is what appeared to be done elsewhere that constructs
> offset_ints).
>
> Tested by bootstrap+check-{gcc,g++,ada,fortran} with the rest of the patchset
> (which causes an array[-1..1] to be completely scalarized, among others), on
> x86_64 and ARM.
>
> I don't have a test without all that (such would have to be in Ada, and
> trigger
> SRA of such an array but not involving the constant pool); is it OK without?
Ok.
Richard.
> gcc/ChangeLog:
>
> * tree-sra.c (completely_scalarize): Properly handle negative array
> indices using offset_int.
> ---
> gcc/tree-sra.c | 23 +++++++++++++++--------
> 1 file changed, 15 insertions(+), 8 deletions(-)
>
> diff --git a/gcc/tree-sra.c b/gcc/tree-sra.c
> index e15df1f..6168a7e 100644
> --- a/gcc/tree-sra.c
> +++ b/gcc/tree-sra.c
> @@ -1010,18 +1010,25 @@ completely_scalarize (tree base, tree decl_type,
> HOST_WIDE_INT offset, tree ref)
> if (maxidx)
> {
> gcc_assert (TREE_CODE (maxidx) == INTEGER_CST);
> - /* MINIDX and MAXIDX are inclusive. Try to avoid overflow. */
> - unsigned HOST_WIDE_INT lenp1 = tree_to_shwi (maxidx)
> - - tree_to_shwi (minidx);
> - unsigned HOST_WIDE_INT idx = 0;
> - do
> + tree domain = TYPE_DOMAIN (decl_type);
> + /* MINIDX and MAXIDX are inclusive, and must be interpreted in
> + DOMAIN (e.g. signed int, whereas min/max may be size_int). */
> + offset_int idx = wi::to_offset (minidx);
> + offset_int max = wi::to_offset (maxidx);
> + if (!TYPE_UNSIGNED (domain))
> {
> - tree nref = build4 (ARRAY_REF, elemtype, ref, size_int (idx),
> + idx = wi::sext (idx, TYPE_PRECISION (domain));
> + max = wi::sext (max, TYPE_PRECISION (domain));
> + }
> + for (int el_off = offset; wi::les_p (idx, max); ++idx)
> + {
> + tree nref = build4 (ARRAY_REF, elemtype,
> + ref,
> + wide_int_to_tree (domain, idx),
> NULL_TREE, NULL_TREE);
> - int el_off = offset + idx * el_size;
> scalarize_elem (base, el_off, el_size, nref, elemtype);
> + el_off += el_size;
> }
> - while (++idx <= lenp1);
> }
> }
> break;
> --
> 1.9.1
>
