As we discussed in D138639, we usually omit In64BitMode on instructions that
have a GR64 operand b/c
- Assembler would never parse a GR64 register name outside of 64-bit mode
- GR64/i64 is not legal during ISEL outside of 64-bit mode
- Adding them might increase the size of the table in X86GenDAGISel.inc
For instructions that do not have an explicit GR64 operand, they're assumed to have an implicit In64BitMode predicate when W bit is set in AsmParser.
Since no test fails w/o the change in AsmParser, I add a test in this patch.
I will do similar clean in other files if this patch is accepted.
The issue also appears on the VEX and EVEX encoded memory form of vextractps.