[llvm] [X86] Support EGPR (R16-R31) for APX (PR #67702)

[Craig Topper via llvm-commits]

topperc wrote:

> The return value of `TRI::getNumRegs()` is a constant generated by tablgen, which is same for all cpus for one target.

I assume getNumRegs is the total number of registers defined in the enum in X86GenRegisterInfo.inc and the new registers are not at the end of that enum?

https://github.com/llvm/llvm-project/pull/67702