[llvm] [DAG] Add freeze(assertext(x)) -> assertext(x) folds (PR #94491)

[Nikita Popov via llvm-commits]

nikic wrote:

> So we need instant-UB specifically for calling-convention stuff? I guess that makes sense. Do we actually freeze operands to calls to ensure the bits are set correctly, though?

We don't, but I didn't think this would be necessary. Do you have a problematic example in mind?

https://github.com/llvm/llvm-project/pull/94491