Model __builtin_assume. The motivation behind using __builtin_assume from the analyzers point of view is to add assumptions. The conventional way to express invariants is to use asserts (with correct annotations for noreturn functions). However on some platform the users do not want to pay the price of an assert, even in the debug build (especially in a hot code). This way we can express these invariants to the analyzer without runtime overhead. Also it is good to use these constraints even if they are only there to aid the optimizer.
What do you think?