[llvm] [X86] Reduce znver3/4 LoopMicroOpBufferSize to practical loop unrolling values (PR #91340)

[Nikita Popov via llvm-commits]

nikic wrote:

I didn't really get why it makes sense to multiply the uop fetch rate with the mispredict penalty.

Also, while znver4 might in theory support 9 uops per cycle, isn't it limited by the 6 wide renamer in practice?

https://github.com/llvm/llvm-project/pull/91340