[clang] [llvm] [ImmutableSet] Optimize add/remove operations to avoid redundant tree modifications (PR #159845)

[Arseniy Zaostrovnykh via llvm-commits]

necto wrote:

> cc., @steakhal , @necto , @NagyDonat , you might want to run some benchmarks with this patch applied to see if there is a measurable impact on the Clang Static Analyzer.

Thank you for the heads up, @Xazax-hun, I will run some benchmarking. I guess I don't need to block the PR on this. If I discover a regression, I'll raise a follow up issue.

https://github.com/llvm/llvm-project/pull/159845