4 ms·

It is completely useless to allow compilers to assume false things about the code they generate.

• fooker 5y ago
  It’s not useless. The assumption is not false if the program doesn’t have undefined behavior. The assumption allows the code to be a few times faster. To disallow this assumption would inhibit these optimizations.
  • vyodaiken 5y ago
    a) the assumption is not false if it is not false! b) the speedup is not shown anywhere
    • fooker 5y ago
      The speedup is more or less the difference between O1 and O3 optimization levels.