URGENT RFR: 8041141: JDK9 emb build failure on PPC platform

[David Holmes]

Hi Andrew,

On 12/06/2014 3:03 AM, Andrew Hughes wrote:
> ----- Original Message -----
>> http://cr.openjdk.java.net/~dholmes/8041141/webrev/
>>
>> The recent changes to convert warnings to errors didn't account for some
>> type-punning warnings in our Embedded PPC build due to the use of
>> strict-aliasing. Really we shouldn't be using strict-aliasing so this
>> change (which for some reason is in the open flags.m4 file) brings ppc
>> in-line with all other platforms and sets -fno-strict-aliasing
>>
>> I will be pushing this to jdk9/dev as we need this fixed immediately.
>>
>> Thanks,
>> David
>>
>
> Hi David,
>
> I just stumbled across this when trying to work out why we are seeing aliasing
> warnings in the demo code only on PPC builds. They get flagged by our build process.
> This exclusion of fno-strict-aliasing on PPC seems to date back to 7027910 in OpenJDK
> 7, where we are seeing the warnings, and there seems to be no explanation as to why
> it was added in either the code or reviews.

It was copied from our internal build instructions. The new build 
unfortunately required it to be exposed in flags.m4.

> Given -fno-strict-aliasing is now being used on all architectures in 9, do you think
> it's ok to do the same in 7? I could also turn it off on the individual files, but
> this would duplicate the flag on other architectures and we may then get more PPC-only
> warnings in future.

I think it should be fine in principle. I'm not sure what the actual 
change in 7 would be.

David
-----

> Thanks,
>