[llvm] [ADT] Add DenseSet(llvm::from_t, Range) (PR #131832)

[Nikita Popov via llvm-commits]

nikic wrote:

> Hi @kazutakahirata,
> 
> I thought about this over the week and I think this proposal is the most reasonable one after all. The issue with adding a range constructor is that it may lead to unintentional copies like with `DesneSet<int64_t> foo = bar();` where `bar()` returns `DenseSet<int>` or some other compatible type.

Wouldn't using an explicit ctor avoid that? That's what SmallVector does.

https://github.com/llvm/llvm-project/pull/131832