Method addDep

chapter20/src/main/java/com/seaofnodes/simple/node/Node.java:549–560

Add a node to the list of dependencies. Only add it if its not an input or output of this node, that is, it is at least one step away. The node being added must benefit from this node being peepholed.

( Node dep )

    // If the _hash is set, then the Node is in the GVN table; remove it.
    void unlock() {
        if( _hash==0 ) return;
        Node old = CODE._gvn.remove(this); // Pull from table
        assert old==this;
        _hash=0;                // Out of table now
    }

    // Hash of opcode and inputs
    @Override public final int hashCode() {
        if( _hash != 0 ) return _hash;
        int hash = hash();
        for( Node n : _inputs )
            if( n != null )
                hash = hash ^ (hash<<17) ^ (hash>>13) ^ n._nid;
        if( hash==0 ) hash = 0xDEADBEEF; // Bad hash, so use some junky thing
        return (_hash=hash);