alt Hacker News> Having an understanding of how the code gets transformed into machine code helps
I'm not sure about that. Knowing assembly is not a substitute for knowing how the language is defined. Sometimes C/C++ programmers with some assembly knowledge reason themselves into thinking that what they're asking of the language must have well-defined behaviour, when in fact it's undefined behaviour. It doesn't really matter whether interleaving order can change the output. (++i)++ is, apparently [0], undefined behaviour in C but has well defined behaviour in C++.
I don't mean assembly in this case, but something more like the compiler's view of the code. a++ can be broken down into more primitive operations, and might actually be, depending on how the compiler is implemented. The fact that the ordering of those more primitive operations with respect to other operations isn't very tightly constrained is something you'd just have to know about the language, I suppose.