PATCH: Check rex_ignored

[Jan Beulich]

>>> "H.J. Lu" <hongjiu.lu@intel.com> 14.11.09 00:14 >>>
>For VEX insn, REX prefix will be ignored. I checked in this patch to
>fix it.

Intel® Advanced Vector Extensions Programming Reference (rev 006)
section 4.1.3 says "Any VEX-encoded instruction with a REX prefix
proceeding VEX will #UD", and I'd think the disassembler should express
this.

(Btw., would it be possible for you doc folks to include revision histories
in documents like this? It's rather hard to see what changed from e.g.
the previous rev of that doc.)

Jan