[llvm] [PowerPC] Remove carry register (PR #142420)

[via llvm-commits]

RolandF77 wrote:

Hmm. OK, I see what you mean - the compiler can't currently tell the difference internally because XER and Carry are set to the same value in PPCRegisterInfo.td.

However, in PPCInstrInfo.td care is taken to differentiate between them. Seems like it would be more accurate to make Carry a subregister, but OV references are just represented as XER currently so there might be no practical benefit. Looks like your change is fine, though it feels to me like a step backward.

https://github.com/llvm/llvm-project/pull/142420