why the values in ssa block can be unordered?

[xie cui]

https://github.com/golang/go/blob/master/src/cmd/compile/internal/ssa/block.go#L60

in my opinion, the values are like instructions, why can it be unordered?

[Keith Randall]

All the ordering required is explicit in the representation. If x is an argument of y, then x must come before y (in the eventual assembly output).

There is no other need for ordering within a basic block. Any order consistent with the argument ordering I mentioned above is ok.