[vlovich123]

What you actually want is to enable some kind automatic trapping behavior when a section of code is entered so that you can say “this set of math operations shouldn’t overflow”. That’s cheaper than what overflow bits get you although entering/exiting such a mode may be equally or more expensive.

The existence of the overflow bits and that overflow continues to remain a common security flaw indicates that there’s a disconnect between the mental model users have when writing this kind of arithmetic (ie they don’t think about it generally and C integer promotion rules don’t do any favors) and how CPU designers imagine you write code.

[scoutt]

> you can say “this set of math operations shouldn’t overflow”

This is the same as putting an "if" statement to check for sizes (before or after the operation); the thing that other languages automatically do for you at runtime (with its performance implications).

> The existence of the overflow bits and that overflow continues to remain a common security flaw

What do you propose for a new CPU architecture/instruction set/register types?

How would you implement it? Signed registers?

> how CPU designers imagine you write code.

Write a program in assembler. You'll be checking carry/overflow bits in no-time.