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

[Christophe Lyon <christophe dot lyon at linaro dot org>]

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.

Attachment: neon-vext-big-endian-tests.patch
Description: Binary data