Comment by benj111

>No, that's wrong. Implementation-Defined Behavior is supposed to allow C to be implemented on different architectures.

Is it? We're talking about integer overflow here.

I wasn't in the meetings when writing all the c standards. I'm not convinced this is purely an optimisation thing though.

I would guess the story is more.

Interested party X: "can integer overflow do X?"

Party Y: "no because our processor doesn't work like that.

Party Z: "and it breaks K and R"

Party X: "how about implementation defined?"

Party A: "but our compiler targets 5 different processors"

Party B: "plus that precludes certain optimisations"