[OpenJDK 2D-Dev] RFR: JDK-8160294: Some client libraries cannot be bult with GCC 6

[Jim Graham]

I agree, it looks more like an overflow error, but the new code is technically more correct so this is more of a comment 
on their error reporting than on the resulting fix.  If you ignore the "Werror=" part of the comment, it is true that 
val overflows a signed int on the 127th iteration, which means they've done some sort of deep dive on analyzing the 
activity of the loop.  Perhaps "aggressive-loop-optimizion" is more of a comment on the fact that they aggressively 
computed what the loop was doing in all 256 iterations when they discovered the overflow?

In any case, the AlphaMath fix looks fine...

			...jim

On 6/27/16 3:44 PM, Phil Race wrote:
> I think these are all OK.
> Regarding the AlphaMath change, I get that we may have
> the use of signed int means the undefined result would
> be for that .. but it doesn't seem to impact the loop
> conditions so I don't understand why that causes a problem
> for loop optimisation. Still, the change is fine.
>
> -phil.
>
> On 06/27/2016 08:59 AM, Erik Joelsson wrote:
>> Build changes look ok.
>>
>> /Erik
>>
>> On 2016-06-27 15:55, Yasumasa Suenaga wrote:
>>> Hi,
>>>
>>> Erik commented that the changes in Awt2dLibraries.gmk should use DISABLED_WARNINGS_gcc
>>> parameter.
>>>
>>> So I use it in new webrev.
>>> Could you review it?
>>>
>>>   http://cr.openjdk.java.net/~ysuenaga/JDK-8160294/webrev.01/
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> On 2016/06/26 11:14, Yasumasa Suenaga wrote:
>>>> Hi Phil,
>>>>
>>>> I've added all warning (error) messages to JIRA.
>>>> Could you review them?
>>>>
>>>>   https://bugs.openjdk.java.net/browse/JDK-8160294
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>> On 2016/06/26 0:40, Philip Race wrote:
>>>>>
>>>>> Could you share all warning messages that you received ?
>>>>> Adding them to the bug report is probably best.
>>>>> I feel much better reviewing these kinds of changes when
>>>>> I can see for myself what the issue is.
>>>>>
>>>>> -phil.
>>>>>
>>>>> On 6/25/16, 6:40 AM, Yasumasa Suenaga wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> This review request relates to [1].
>>>>>>
>>>>>> Some client libraries could not be built with misleading-indentation
>>>>>> and shift-negative-value warning (error) on GCC 6.1.1 .
>>>>>>
>>>>>> So I think we have to fix new warnings.
>>>>>>
>>>>>> However, some libraries (LCMS, JPEG library) are imported from another
>>>>>> open source project. So we should avoid compile error with suppressing
>>>>>> them.
>>>>>>
>>>>>> I uploaded a webrev.
>>>>>> Could you review it?
>>>>>>
>>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8160294/webrev.00/
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>>>
>>>>>> [1] http://mail.openjdk.java.net/pipermail/jdk9-dev/2016-June/004494.html
>>
>