Unnecessary store/load

[nsc-de]

This is posted as an issue because it needs further thinking.

If we have a function like:

fun add(a: int, b: int): int {
    return a + b;
}

The compiler will output the following instructions:

istore 0
istore 4
iload 4
iload 0
iadd
iret
ret

More efficient way would be:

iadd
iret
ret

Should such edge cases be addressed? For some operators (-, /) this optimization would just work when the arguments have the correct order (for others we need swapping)