We present the first thin-air free memory model that admits compiler optimisations that aggressively leverage knowledge from alias analysis, an assumption of freedom from undefined behaviour, and from the extrinsic choices of real implementations such as over-alignment. Our model has tooling support with state-of-the-art performance, executing a battery of tests orders of magnitude quicker than other executable thin-air free semantics. The model integrates with the C/C++ memory model through an exportable semantic dependency relation, it allows standard compilation mappings for atomics, and it matches all tests in the recently published desiderata for C/C++ from the ISO.

@article{paperbot3188,
  title = {Symbolic MRD: Dynamic Memory, Undefined Behaviour, and Extrinsic Choice},
  author = {Jay Richards and Daniel Wright and Simon Cooksey and Mark Batty},
  journal = {Proceedings of the ACM on Programming Languages},
  volume = {9},
  number = {OOPSLA1},
  year = {2025},
  doi = {10.1145/3721089}
}