[astrange]

This is a typical whining about UB article, but removing it won't get what you want, in particular your program still won't behave correctly across architectures. Overflow on shift left may be undefined, but how do you want to define it? If you want a "high level assembler", well, the underlying instructions behave differently on ARM, x86 scalar, and x86 SIMD.

The reason they claim program optimizations aren't important is because you can do it by hand for a specific architecture pretty easily, but you'll still want them when porting to a new one, eg if it wants loop counters to go in the opposite direction.

[vyodaiken]

Nobody claims optimizations are not important.

[Asooka]

Yes, your program will have different semantics on different architectures. This is already the case with e.g. big vs little endian. But you will be able to reason about the program's semantics rather than going "I sure hope there's no UB in here" and throwing your hands up.