[clang] [Clang] Generate the GEP instead of adding AST nodes (PR #73730)

[Eli Friedman via cfe-commits]

efriedma-quic wrote:

I don't like the "ExprLValueMap" approach for array bounds checking; it's fragile and doesn't handle cases we should be able to handle.  In particular, we should be able to handle arbitrary base expressions for array bounds checking, I think; there should be a constant offset between a member and its corresponding count.  I'd strongly prefer the approach I outlined earlier (https://github.com/llvm/llvm-project/pull/73730#discussion_r1410000039).

https://github.com/llvm/llvm-project/pull/73730