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

[Simon Pilgrim via llvm-commits]

RKSimon wrote:

Can you give any more information on what nodes you are adding that causes such a problem? Are you adding a large number of TokenFactors or something?

I should also mention #83422 which will/would/maybe help with compile times in the DAG :)

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