On Tuesday, 4 March 2025 08:27:05 Pacific Standard Time Jarrad Waterloo via
Std-Proposals wrote:
> Reproducible functions should only be able to call other reproducible and
> unsequenced functions.
> Unsequenced functions should only be able to call other unsequenced
> functions.
>
> Compilers need to track these properties for functions similar to how it is
> done for constexpr and consteval functions.

As discussed, strlen() is pure, but what should I do if the C library vendor
did not mark it as such? Should I have to roll out my own, much less efficient
version?

What happens if the function reads from a non-const global variable? How is
the compiler to know if that variable has an unchangeable value after the
program start?

What should compilers do when seeing an asm block? The contents of that are
entirely implementation-defined, but the "asm" keyword is part of the language.

Is an unsequenced function allowed to change the floating point environment?
Before you answer "no", think about 1.0/3.0 setting the #I bit.

As others said, verification should be highly encouraged but not required,
which means it's at most a warning and it can be disabled with a pragma.

-- 
Thiago Macieira - thiago (AT) macieira.info - thiago (AT) kde.org
  Principal Engineer - Intel DCAI Platform & System Engineering