Re: [PATCH GCC]Pick up more address lowering cases for ivopt and tree-affine.c

[Richard Biener <richard dot guenther at gmail dot com>]

On Fri, Dec 6, 2013 at 11:40 AM, Bin.Cheng <amker.cheng@gmail.com> wrote:
> On Fri, Dec 6, 2013 at 6:19 PM, Richard Biener
> <richard.guenther@gmail.com> wrote:
>> On Mon, Nov 25, 2013 at 7:41 PM, Jeff Law <law@redhat.com> wrote:
>>> On 11/25/13 02:22, bin.cheng wrote:
>>>
>>> Unless there's a PR for this problem, I think this needs to wait.
>>
>> I agree.  Btw, please split the patch.
> Yes, I will get back to this after entering stage 1 again :)
>
> Hi Richard,
> I talked with you about clean strip_offset_1 up after this series of
> base simplification patches, but I realized it's not safe because
> affine facility has it's limit, like can only support 8 elements.
> Though the cleanup passes bootstrap and test on x86/x86_64 and most of
> codes in strip_offset_1 won't be executed usually, I guess we'd better
> to live with it, so what do you think?

Not sure - I'm lacking some context here ;)  If you have a cleanup patch
fine - WRT the affine limit of 8 elements, further elements will just
add to the rest tree.  This is to limit compile-time.

Richard.

> Thanks,
> bin
>
>>
>> Index: gcc/tree-affine.c
>> ===================================================================
>> --- gcc/tree-affine.c    (revision 205087)
>> +++ gcc/tree-affine.c    (working copy)
>> @@ -328,7 +328,19 @@ tree_to_aff_combination (tree expr, tree type, aff
>>                   double_int::from_uhwi (bitpos / BITS_PER_UNIT));
>>        core = build_fold_addr_expr (core);
>>        if (TREE_CODE (core) == ADDR_EXPR)
>> -    aff_combination_add_elt (comb, core, double_int_one);
>> +    {
>> +      /* Handle &MEM[ptr + CST] in core part of complex reference.  */
>> +      if (TREE_CODE (TREE_OPERAND (core, 0)) == MEM_REF)
>> +        {
>> +          core = TREE_OPERAND (core, 0);
>> +          tree_to_aff_combination (TREE_OPERAND (core, 0), type, &tmp);
>> +          aff_combination_add (comb, &tmp);
>> +          tree_to_aff_combination (TREE_OPERAND (core, 1), sizetype, &tmp);
>> +          aff_combination_add (comb, &tmp);
>> +        }
>> +      else
>> +        aff_combination_add_elt (comb, core, double_int_one);
>> +    }
>>        else
>>      {
>>        tree_to_aff_combination (core, type, &tmp)
>>
>> please handle the offset before taking the address, thus
>>
>>   if (TREE_CODE (core) == MEM_REF)
>>     {
>>        add constant offset;
>>        core = TREE_OPERAND (core, 0);
>>     }
>>   else
>>     core = build_fold_addr_expr (core);
>>
>> that simplifies things and avoids the address building.
>>
>> Richard.
>>
>>> jeff
>>>
>>>
>
>
>
> --
> Best Regards.