[llvm] [X86] Support peephole optimization with CCMP instruction (PR #129994)

[Feng Zou via llvm-commits]

fzou1 wrote:

> I think https://github.com/llvm/llvm-project/blob/main/llvm/test/CodeGen/X86/apx/ccmp.ll should reflect your change?

For now, there is no such pattern in that LIT test. I'll add some sub-tests to validate this optimization.

https://github.com/llvm/llvm-project/pull/129994