In practice I think it is hard to beat C in this regard. You can go pretty far if you are willing adapt to its quirks! And while C doesn't always allow for the

In practice I think it is hard to beat C in this regard. You can go pretty far if you are willing adapt to its quirks! And while C doesn't always allow for the best optimization (such as returning multiple values via registers), the workarounds often are still pretty fast. On a more theoretical level there has been some research on what a better intermediate language would look like. One project I found interesting was Mu VM, which offers some niceties for compiling languages with a garbage collector. https://microvm.github.io/ https://microvm.github.io/