[Patch ARM] big-endian support for Neon vext tests

[Christophe Lyon]

On 17 September 2012 14:56, Richard Earnshaw <rearnsha@arm.com> wrote:
> On 05/09/12 23:14, Christophe Lyon wrote:
>> Hello,
>>
>> Although the recent optimization I have committed to use Neon vext
>> instruction for suitable builtin_shuffle calls does not support
>> big-endian yet, I have written a patch to the existing testcases such
>> they now support big-endian mode.
>>
>> I think it's worth improving these tests since writing the right masks
>> for big-endian (such that the program computes the same results as in
>> little-endian) is not always straightforward.
>>
>> In particular:
>> * I have added some comments in a few tests were it took me a while to
>> find the right mask.
>> * In the case of the test which is executed, I had to force the
>> noinline attribute on the helper functions, otherwise the computed
>> results are wrong in big-endian. It is probably an overkill workaround
>> but it works :-)
>>   I am going to file a bugzilla for this problem.
>>
>> I have checked that replacing calls to builtin_shuffle by the expected
>> Neon vext variant produces the expected results in big-endian mode,
>> and I arranged the big-endian masks to get the same results.
>>
>> Christophe.=
>>
>>
>> neon-vext-big-endian-tests.patch
>>
>>
>> N ¬n‡r¥ªíÂ)emçhÂyhi× ¢w^™©Ý
>>
>
>
> I'm not sure about this.  Looking at the documentation in the manual for
> builtin_suffle makes no mention of the results/behaviour being endian
> dependent, which makes me wonder why this test needs to be.
>
> R.


Indeed, but I had to modify the mask value in order to get the same
results in big and little-endian.

If the mask should be the same (it would be much more confortable for
the developers indeed), then GCC needs to be changed/fixed.

Christophe.