[llvm] [SROA] Use SmallPtrSet for PromotableAllocas (PR #105809)

[Sergei Barannikov via llvm-commits]

s-barannikov wrote:

> You'd need a set container with stable order like SetVector -- though I think that one doesn't actually have efficient erase.

Maybe `SetVector<T, std::deque<T>>` can be used?


https://github.com/llvm/llvm-project/pull/105809