The meat of this is in the second patch, which makes the AArch64 backend look
for shuffle masks that can be turned into REV instructions, and updates the VREV
Neon Intrinsics to use __builtin_shuffle rather than the current inline
assembler; this then produces the same instructions (unless the midend can do
better).
Before that, the first patch adds execution + assembler tests of the existing
intrinsics, which then serve as a testcase for the second patch.
Third patch reuses the test bodies from first patch in equivalent tests on the
ARM architecture.
Ok for trunk?
--Alan
