[llvm] [PowerPC] Add flag to DAG combiner to improve compile time. (PR #86884)

[Stefan Pintilie via llvm-commits]

stefanp-ibm wrote:

> I think we should close this now?

It's not worth adding the extra flag considering that this is very much a special case. 
Closing this issue now. 

https://github.com/llvm/llvm-project/pull/86884