Method popN

chapter04/src/main/java/com/seaofnodes/simple/node/Node.java:183–190

(int n)

    // Shortcut for "popping" n nodes.  A "pop" is basically a
    // setDef(last,null) followed by lowering the nIns() count.
    void popN(int n) {
        for( int i=0; i<n; i++ ) {
            Node old_def = _inputs.removeLast();
            if( old_def != null &&     // If it exists and
                old_def.delUse(this) ) // If we removed the last use, the old def is now dead
                old_def.kill();        // Kill old def
        }
    }

    /**
     * Kill a Node with no <em>uses</em>, by setting all of its <em>defs</em>