It has been observed that the issue width for neoverse-n2 CPUs is set
too high, and does not properly reflect the dispatch constraints.
I tested various values of IssueWidth (10, 8, 6, 5, 4) with runs of
various workloads on a neoverse-n2 machine and I got the highest overall
geomean score with an issue width of 5.
If this patch were to cause any major regression post-commit, it could
be easily reverted, but it is likely to show an overall improvement.
Related Neoverse-V2 PR: https://github.com/llvm/llvm-project/pull/142565
a1d83311c8