[llvm] promote Pseduo Opcode from 32bit to 64bits after eliminating the `extsw` instruction in PPCMIPeepholes optimization (PR #85451)

[Kamau Bridgeman via llvm-commits]

https://github.com/kamaub commented:

Can we rename the PR to "Promote 32bit Pseduo Opcodes to 64bits when extsw is eliminated".


https://github.com/llvm/llvm-project/pull/85451