[zAy0LfpBZLC8mAC]

Why shouldn't the compiler be able to figure out that you sum a series of numbers that aren't used anywhere else, thus don't need to be spilled to RAM?

[xxs]

You write them to a global state volatile

[zAy0LfpBZLC8mAC]

How does that require writing the random data to RAM, apart from the volatile variable itself?