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Re: Fix PR41879 (large mgrid regression)
On Mon, Jan 18, 2010 at 9:12 PM, Toon Moene <toon@moene.org> wrote:
> Richard Guenther wrote:
>
>> On Sat, Jan 16, 2010 at 11:24 PM, Michael Matz <matz@suse.de> wrote:
>
>>> Given the above, should I still do this?
>
>> I think you can end up with
>>
>> ?tmp_6 = ptr_7 + 8;
>> ?tmp_5 = (sizetype) tmp_6;
>> ?tmp_1 = (short) tmp_5;
>> ?tmp_2 = (sizetype) tmp_1;
>> ?ptr_4 = ptr_3 + tmp_2;
>>
>> where you'd drop the truncation when splitting ptr_3 + tmp_2.
>>
>> So I think yes, better play safe for now given that we're late for 4.5
>> already.
>
> Hmmm, does this mean this route won't be explored before 4.6 ? ?(this isn't
> exactly clear from the exchange above).
>
> I'm willing to test this on some real world Fortran code later this week, if
> you're interested (against the current 4.5).
We settled on allowing conversions from signed or pointer types
if that conversion is widening or doesn't change precision.
Unfortunately that isn't enough to fix mgrid - Micha is still trying
to fix that.
Richard.