I don't know. Unfortunately we don't have an Oberon compiler doing similar optimization as e.g. GCC, so we can only speculate. I did measurements some time ago to compare a typical Oberon compiler on x86 with GCC and the performance was roughly equivalent to that of GCC without optimizations (see https://github.com/rochus-keller/Are-we-fast-yet/tree/main/O...). The C++ type system is also pretty strict, and on the other hand it's possible and even unavoidable in the Oberon system 3 to do pointer arithmetics and other things common in C behind the compiler's back (via the SYSTEM module features which are not even type safe). So the original Oberon syntax and semantics is likely not on the sweet spot of systems programming. With my Micron (i.e. Micro Oberon, see https://github.com/rochus-keller/micron/) language currently in development I try for one part to get closer to C in terms of features and performance, but with stricter type safety, and on the other hand it also supports high-level applications e.g. with a garbage collector; the availabiltiy of features is controlled via language levels which are selected on module level. This design can be regarded as a consequence of many years of studying/working with Wirth languages and the Oberon system.

There was a couple of PhD theses at ETH Zurich in the 90s on optimizations for Oberon, as well as SSA support. I haven't looked at your language yet, but depending on how advanced your compiler is, and how similar to Oberon, they might be worth looking up.