Consider an aliasing restriction to make mem2reg easier

[jfecher]

Problem

Mem2reg is now the most complex SSA pass and has a large surface area for miscompilation bugs.

Happy Case

Mem2reg could be simplified if we can assume that aliases to a reference cannot be used while another is "active" / borrowed. This would be similar to rust's aliasability xor mutability rule. We should consider this as an option since aliasing mutable references is rare in practice.

Workaround

None

Workaround Description

No response

Additional Context

No response

Project Impact

None

Blocker Context

No response

Would you like to submit a PR for this Issue?

None

Support Needs

No response

[jfecher]

The downside of this is that it'd require we implement a borrow checker

[sirasistant]

Would this be connected with having ownership semantics instead of immutability or is it a completely separate problem space?