[AArch64] Let aliased instructions be their preferred form.

[Nick Clifton]

Hi Matthew,

> I don't there's any test that could be done using the existing
> instructions. The aliasing change is needed for the REV64 alias of the
> REV instruction
> (https://sourceware.org/ml/binutils/2015-11/msg00222.html) patch. That
> includes tests that check that the instruction REV is preferred over its
> aliases so are also  a test of this patch (which should probably have
> been sent as part of the BFM, REV patch set).

Ah - that explains it.  In which case please consider the patch to be 
approved.

Cheers
   Nick