One word, portability. Since C is relatively low level, allows direct access to mem, primitive types correspond to actual machine types, etc. It can be crippli

One word, portability. Since C is relatively low level, allows direct access to mem, primitive types correspond to actual machine types, etc. It can be crippling for a low level language that targets many many architectures to define undefined behavior. For example, it is undefined behavior to overflow a signed integer. Now, I can't think of a modern processor that doesn't use two's complement so this behavior is relatively well defined, but theoretically if there was a processor that doesn't use two's complement and signed integer overflow was well defined in C, then the compiler would have to insert a workaround which could hinder performance, have unintended side effects, or just be impossible to workaround. One of the best features of C is how portable it is, it is the defacto standard for any risc architecture, be it a tiny microcontroller or a beefy modern processor, a C compiler targets it. The cost of this portability is undefined behavior.