On Tue, Nov 5, 2013 at 1:18 PM, Yufeng Zhang <yufeng.zh...@arm.com> wrote:
> On 11/05/13 11:45, Bin.Cheng wrote:
>>
>> On Tue, Nov 5, 2013 at 7:19 PM, Yufeng Zhang<yufeng.zh...@arm.com> wrote:
>>>
>>> > On 11/05/13 10:13, bin.cheng wrote:
>>>>
>>>> >>
>>>> >> Index: gcc/tree-affine.c
>>>> >> ===================================================================
>>>> >> --- gcc/tree-affine.c (revision 204117)
>>>> >> +++ gcc/tree-affine.c (working copy)
>>>> >> @@ -874,10 +874,11 @@ debug_aff (aff_tree *val)
>>>> >> fprintf (stderr, "\n");
>>>> >> }
>>>> >>
>>>> >> -/* Returns address of the reference REF in ADDR. The size of the
>>>> >> accessed
>>>> >> - location is stored to SIZE. */
>>>> >> +/* Computes address of the reference REF in ADDR. The size of the
>>>> >> accessed
>>>> >> + location is stored to SIZE. Returns pointer to the ultimate
>>>> >> containing
>>>> >> + object to which REF refers. */
>>>> >>
>>>> >> -void
>>>> >> +tree
>>>> >> get_inner_reference_aff (tree ref, aff_tree *addr, double_int
>>>> >> *size)
>>>> >> {
>>>> >> HOST_WIDE_INT bitsize, bitpos;
>>>> >> @@ -904,6 +905,8 @@ get_inner_reference_aff (tree ref, aff_tree
>>>> >> *addr,
>>>> >> aff_combination_add (addr,&tmp);
>>>> >>
>>>> >> *size = double_int::from_shwi ((bitsize + BITS_PER_UNIT - 1) /
>>>> >> BITS_PER_UNIT);
>>>> >> +
>>>> >> + return base_addr;
>>>> >> }
>>>> >>
>>>
>>> >
>>> > I think what Richard suggests is to return the base object rather the
>>> > address of the base object, i.e.
>>
>> I am not sure about that. We have to pass pointer_type expression to
>> function determine_base_object for address expressions, because there
>> is no way to tell pointer from object once we are in
>> determine_base_object.
>
>
> I'm just concerned with the consistency in what is returned between
> get_inner_reference and get_inner_reference_aff. If determine_base_object
> expects reference only, you can probably work around it with something like:
>
> base_object = build_fold_addr_expr (base_object);
>
> after the get_inner_reference_aff call.
Note that get_inner_reference_aff is already different from get_inner_reference
in that it does not separate base object and offset but lumps them together
into an address represented as affine combination.
For this reason get_inner_reference_aff may not exactly be the best
name for the function ... it could be split to not do
aff_combination_add (addr, &tmp);
but instead return 'base'. The two existing users of the function could
be unified into aff_comb_cannot_overlap_p (giving that a better name
as well), even avoiding combining the base but instead handle
comparing the base itself.
Of course that's preexisting issues that I don't want to force Bin Cheng
to clean up and fix (given I've, too, just spent a minute thinking about it).
Thanks,
Richard.
> Yufeng
>
