Who's afraid of a big bad optimizing compiler?

Surely a simple way for the standards committee would simply be to define a bunch of pragmas that said "this implementation-defined feature is required", and say that the compiler must terminate with a fatal error if it's not supported.

Okay, that then means that the poor programmer needs to add a bunch of requirements at the start of his program, but it also means that if he attempts to port to a different architecture that doesn't support his assumptions, the compiler will refuse to compile. Much better than everything appearing to work and then falling over in a heap in production.

Cheers,
Wol