You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: analysis.go
    path of file: ./repos/gorgonia
    
    the code of the file until where you have to start completion: package gorgonia

import (
	"bytes"
	"fmt"
)

// dataflow analysis

type dataflow struct {
	uniques map[uint32]*Node

	replacements map[*Node]*Node
	intervals    map[*Node]*
    
func (df *dataflow) vn(n *Node) (retVal *Node, unique bool) {
	compileLogf("Value numbering")
	enterLogScope()
	defer leaveLogScope()

	node, ok := df.uniques[n.Hashcode()]

	if ok {
		return node, false
	}

	compileLogf("adding a new unique")
	// otherwise, add it to uniques, and then return itself
	df.uniques[n.Hashcode()] = n

	return n, true
}