This adds an EVEX2VEXOverride string to the X86 instruction class in X86InstrFormats.td. If this field is set it will add manual entry in the EVEX->VEX tables that doesn't check the encoding information.
Then use this mechanism to map VMOVDU/A8/16, 128-bit VALIGN, and VPSHUFF/I instructions to VEX instructions.
Finally, remove the manual table from the emitter.
This has the bonus of fully sorting the autogenerated EVEX->VEX tables by their EVEX instruction enum value. We may be able to use this to do a binary search for the conversion and get rid of the need to create a DenseMap.
llvm-svn: 335018