What happens when we write delay instruction twice continuously in an MSP430?
__delay_cycles(const int) is an intrinsic function. That means the compiler substitutes predesigned assembly for the function, and it is not optimized in any way by the optimizer in the compiler. Inserting it twice means that the delay is doubled, and code wise, two sets of the same code run back to back. It is not optimized to be a longer delay. A subtle but key difference.

Keep in mind, this is the same reason __delay_cycles only takes a constant, and not a variable. It is analyzed at compile time and cannot function as a run time function.