Method kill

chapter06/src/main/java/com/seaofnodes/simple/node/Node.java:218–223

Kill a Node with no uses , by setting all of its defs to null. This may recursively kill more Nodes and is basically dead code elimination. This function is co-recursive with #popN.

( )

     * code elimination.  This function is co-recursive with {@link #popN}.
     */
    public void kill( ) {
        assert isUnused();      // Has no uses, so it is dead
        popN(nIns());          // Set all inputs to null, recursively killing unused Nodes
        _type=null;             // Flag as dead
        assert isDead();        // Really dead now
    }

    // Mostly used for asserts and printing.
    boolean isDead() { return isUnused() && nIns()==0 && _type==null; }